Practical Recording Techniques Fourth Edition

Practical Recording Techniques Fourth Edition
Practical Recording Techniques, Fourth Edition
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Practical
Recording
Techniques
Fourth Edition
Bruce Bartlett
Jenny Bartlett
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TABLE OF CONTENTS
Preface
xxv
Acknowledgments xxvii
1
Music: Why You Record 1
Increasing Your Involvement in Music 2
Different Ways of Listening 2
Why Record? 3
2
The Recording Chain 5
Types of Recording 6
Live Stereo Recording 7
Live-Mix Recording 8
Separate Multitrack Recorder and Mixer 9
Stand-Alone DAW (Recorder-Mixer) 11
Computer DAW 11
MIDI Sequencing 13
Pros and Cons of Each Method 14
Editing/Mastering 16
Quality Levels of Recording Formats 16
3
Sound, Signals, and Studio Acoustics 19
Sound Wave Creation 19
Characteristics of Sound Waves 21
Amplitude 21
Frequency 21
Wavelength 22
Phase and Phase Shift 22
Phase Interference 23
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Practical Recording Techniques
Harmonics 24
Envelope 25
Behavior of Sound in Rooms 26
Echoes 26
Reverberation 27
Diffusion 29
Leakage 29
How to Tame Echoes, Reverb, and Leakage 30
Controlling Room Problems with Recording Techniques 30
Controlling Room Problems with Acoustic Treatments 30
Controlling Standing Waves 33
Making a Quieter Studio 33
Signal Characteristics of Audio Devices 35
Frequency Response 36
Noise 38
Distortion 38
Optimum Signal Level 38
Signal-to-Noise Ratio 38
Headroom 39
4
Equipping Your Studio 41
Low-Cost Recording Equipment 42
Microphone 42
Monitor System 43
Recording Device 43
Higher-Cost Recording Equipment 48
Mixer 49
Hard-Disk Recorder (HD Recorder) 49
Processors 50
HD Recorder-Mixer with 16 to 32 Tracks 50
High-End Recording Software and Hardware 50
Equipment Details 51
Recorder 51
Mixer 52
Effects 53
Microphones 54
Phantom-Power Supply 54
Mic Preamp 54
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Table of Contents
Direct Box 55
Monitor System 55
Rack and Patch Bay 56
Miscellaneous Equipment 56
Blank Recording Media 56
MIDI Studio Equipment 57
Setting Up Your Studio 59
Cables 59
Equipment Connectors 60
Cable Connectors 61
Cable Types 63
Rack/Patch Bay 65
Equipment Connections 66
Acoustic Treatment 69
Hum Prevention 70
Reducing Radio Frequency Interference 72
5
Monitoring 73
Speaker Requirements 74
NearfieldTM Monitors 75
Powered (Active) Monitors 77
The Power Amplifier 77
Speaker Cables and Polarity 78
Control-Room Acoustics 78
Speaker Placement 80
Using the Monitors 81
Headphones 82
The Cue System 83
Conclusion 85
6
Microphones 87
Transducer Types 87
General Traits of Each Transducer Type 90
Polar Pattern 91
Traits of Various Polar Patterns 93
Frequency Response 94
Impedance (Z) 97
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Practical Recording Techniques
Maximum SPL 97
Sensitivity 97
Self-Noise 98
Signal-to-Noise Ratio 98
Polarity 99
Microphone Types 99
Large-Diaphragm Condenser Microphone 99
Small-Diaphragm Condenser Microphone 99
Dynamic Instrument Microphone 100
Live-Vocal Microphone 100
Ribbon Microphone 100
Boundary Microphone 100
Miniature Microphone 101
Stereo Microphone 102
Digital Microphone 103
Headworn Microphone 103
Microphone Selection 103
Mic Accessories 105
Pop Filter 105
Stands and Booms 105
Shock Mount 106
Cables and Connectors 106
Snake 107
Splitter 107
Summary 108
7
Microphone Technique Basics 109
Which Mic Should I Use? 109
How Many Mics? 111
How Close Should I Place the Mic? 113
Leakage 114
Don’t Mike Too Close 115
Where Should I Place the Mic? 116
On-Surface Techniques 117
The Three-to-One Rule 119
Off-Axis Coloration 120
Stereo Mic Techniques 120
Goals of Stereo Miking 120
Types of Stereo Mic Techniques 121
x
Table of Contents
Comparing the Four Techniques 128
Hardware 129
How to Test Imaging 129
8
Microphone Techniques 131
Electric Guitar 131
Miking the Amp 132
Recording Direct 133
Electric Guitar Effects 134
Electric Bass 135
Synthesizer, Drum Machine, and Electric Piano 137
Leslie Organ Speaker 137
Drum Set 138
Tuning 139
Damping and Noise Control 140
Drum Miking 140
Snare 140
Hi-Hat 142
Tom-Toms 142
Kick Drum 143
Cymbals 144
Room Mics 145
Boundary Mic Techniques 145
Recording with Two to Four Mics 145
Drum Recording Tips 147
Percussion 149
Acoustic Guitar 149
Singer/Guitarist 151
Grand Piano 151
Upright Piano 154
Acoustic Bass 155
Banjo 156
Mandolin, Dobro, Bouzouki, and Lap Dulcimer 157
Hammered Dulcimer 157
Fiddle (Violin) 157
String Section 159
String Quartet 160
Bluegrass Band and Old-Time String Band 160
Harp 160
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Practical Recording Techniques
Horns 161
Saxophone 161
Woodwinds 162
Harmonica, Accordion, and Bagpipe 164
Lead Vocal 164
Miking Distance 165
Breath Pops 166
Wide Dynamic Range 166
Sibilance 167
Reflections from the Music Stand and Ceiling 167
Vocal Effects 168
Background Vocals 168
Spoken Word 169
Choir and Orchestra 169
Summary 170
9
Digital Recording 171
Analog versus Digital 171
Digital Recording 172
Bit Depth 174
Sampling Rate 174
Data Rate and Storage Requirements 175
Digital Recording Level 175
The Clock 176
Digital Audio Signal Formats 176
Converting Signal Formats 177
Dither 177
Jitter 179
Digital Transfers or Copies 180
2-Track Digital Recorders 181
Portable Hard-Drive Recorder 182
The Digital Audio Workstation 183
CD Recordable 183
MiniDisc Recorder 187
Memory Recorder 188
Multitrack Digital Recorders 190
Modular Digital Multitrack 191
Hard-Disk (HD) Recorder 192
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Table of Contents
HD Recorder-Mixer 192
MiniDisc Recorder-Mixer 195
Pros and Cons of Four Multitrack Recording Systems 196
Backup 198
10
Effects and Signal Processors 201
Software Effects (Plug-Ins) 201
Equalizer 202
Types of EQ 203
How to Use EQ 206
When to Use EQ 208
Uses of EQ 209
Compressor 211
Using a Compressor 212
Compression Ratio or Slope 213
Threshold 213
Gain Reduction 213
Attack Time 214
Release Time 214
Output-Level Control 214
Connecting a Compressor 215
Suggested “Ballpark” Compressor Settings 215
Limiter 216
Noise Gate 217
Delay: Echo, Doubling, Chorus, and Flanging 218
Echo 218
Slap Echo 220
Repeating Echo 220
Doubling 220
Chorus 221
Stereo Chorus 221
Bass Chorus 221
Flanging 221
Reverberation 222
Preverb 225
Enhancer 226
Octave Divider 226
Harmonizer 226
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Practical Recording Techniques
Vocal Processor 226
Automatic Pitch Correction 227
Tube Processor 227
Rotary Speaker Simulator 227
Analog Tape Simulator 227
Spatial Processor 227
Microphone Modeler 228
Guitar Amplifier Modeler 228
De-Click, and De-Noise 228
Surround Sound 228
Multieffects Processor 228
Looking Back 229
Sound-Quality Glossary 230
11
Mixers and Mixing Consoles 237
Stages of Recording 237
Mixer Functions and Formats 238
Analog Mixer 239
Input Section 240
Output Section 247
Monitor Section 250
Monitor Select Buttons 250
Monitor Mix Controls and Connectors 250
SOLO 251
Additional Features in Large Mixing Consoles 251
Digital Mixer 253
Digital Mixer Features 254
Software Mixer 254
Controller Surface 255
12
Operating the Multitrack Recorder and
Mixer 257
Session Preparation 258
Recording 258
Assign Inputs to Tracks 259
Set Recording Levels 259
Set EQ 261
Recording 261
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Table of Contents
Playback 261
Overdubbing 262
Punching-In 263
Composite Tracks 264
Getting More Tracks 265
Flying In 265
Drum Replacement 266
Mixdown 267
Set Up the Mixer and Recorders 267
Erase Unwanted Material 268
Panning 269
Compression 270
Set a Balance 270
Set EQ 271
Add Effects 272
Set Levels 272
Judging the Mix 273
Changes During the Mix 274
Record the Mix 275
Summary 276
Recording 277
Overdubbing 277
Mixdown 277
Automated Mixing 278
Types of Automation Systems 279
Snapshot versus Continuous Automation 280
Automated Mixing Procedure 280
13
Computer Recording 283
Basic Operation 284
Recording and Playback 284
Editing 286
Mixdown 288
The Computer 288
Audio Interfaces 289
Sound Card 290
I/O Breakout Box 292
Control Surface 297
Alesis FirePort 299
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Practical Recording Techniques
DSP Card 299
Analog Summing Amplifier 299
Recording Software 300
Features 301
Plug-Ins 302
Examples of DAW Software 303
Optimizing Your Computer for Digital Audio 312
Using a DAW 313
Connections 313
Maintaining Quality 314
14
Judging Sound Quality 317
Classical versus Popular Recording 317
Good Sound in a Pop-Music Recording 318
A Good Mix 319
Wide Range 320
Good Tonal Balance 320
Clean Sound 321
Clarity 321
Smoothness 322
Presence 322
Spaciousness 322
Sharp Transients 322
Tight Bass and Drums 322
Wide and Detailed Stereo Imaging 323
Wide but Controlled Dynamic Range 324
Interesting Sounds 324
Suitable Production 325
Good Sound in a Classical-Music Recording 325
Good Acoustics 325
A Natural Balance 326
Tonal Accuracy 326
Suitable Perspective 326
Accurate Imaging 326
Training Your Hearing 328
Troubleshooting Bad Sound 329
Bad Sound on All Recordings 330
Bad Sound on Playback Only 330
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Table of Contents
Bad Sound in a Pop-Music Recording Session 331
Bad Sound in a Classical-Music Recording 338
15
Session Procedures, Editing, Mastering,
and CD Burning 343
Preproduction 344
Instrumentation 344
Recording Order 344
Track Assignments 345
Session Sheet 345
Production Schedule 346
Track Sheet 346
Microphone Input List 346
Instrument Layout Chart 349
Setting Up the Studio 349
Setting Up the Control Room 350
Session Overview 350
Recording 351
Overdubbing 352
Composite Tracks 352
Drum Overdubs 353
Overdubbing the Control Room 353
Breaking Down 353
Mixdown 354
Mastering 354
Burning a Reference CD 354
Sending Out Your CD for Mastering 356
Mastering Your Own Album 356
Transferring the Mastered Program to CD-R 360
Master Log 362
16
The MIDI Studio: Equipment and Recording
Procedures 365
MIDI-Studio Components 366
MIDI Recording Procedures 372
2-Track Recording of a Synthesizer Performance 372
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Practical Recording Techniques
Multitrack Recording of a Synthesizer Performance 377
Recording with a Keyboard Workstation 380
Recording with a Drum Machine and Synth 383
Recording with MIDI/Audio Recording Software 387
Loop-based Recording 391
“No Sound” MIDI Troubleshooting 394
Summary 395
17
On-Location Recording of Popular Music 397
Two Mics Out Front 398
Equipment 398
Mic Placement 398
Recording 399
Recording from the Sound-Reinforcement Mixer 400
Drawbacks 400
Recording with a 4-tracker 401
Recording Off the FOH Mixer Aux Output 402
Feeding the FOH Mixer Insert Sends to a Multitrack Recorder 404
Connections 404
Monitor Mix 405
Setting Levels 405
Mixdown 405
Feeding the FOH Mixer’s Insert Sends to a Recording Mixer 406
Splitting the Microphones 406
Multitrack Recording in a Van 407
Preparing for the Session 408
Preproduction Meeting 408
Site Survey 409
Mic List 410
Track Sheet 410
Block Diagram 412
Equipment List 412
Preparing for Easier Setup 413
Protective Cases 413
Mic Mounts 414
Snakes and Cables 415
Rack Wiring 415
Other Tips 416
At the Session: Setup 417
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Table of Contents
Power Distribution System 417
Power Source 418
Interconnecting Multiple Sound Systems 419
Connections 421
Running Cables 421
Recording-Console Setup 421
Mic Techniques 422
Electric Guitar Grounding 423
Audience Microphones 424
Setting Levels and Submixes 425
Recording 426
Teardown 427
18
On-Location Recording of Classical
Music 429
Equipment 429
The 2-Track Recorder 430
Microphones 430
Monitors 431
Mic Cables 432
Mic Preamp or Mixer 432
Stereo Microphone Techniques 432
Preparing for the Session 433
Session Setup 434
Microphone Placement 435
Distance 435
Stereo-Spread Control 436
Soloist Pickup and Spot Microphones 437
Recording 437
Editing 438
19
Surround Sound: Techniques and Media 439
Surround Speaker Arrangement 440
Setting Up a Surround Monitoring System 442
Bass Management 443
Surround Mixing Equipment 444
Connections 445
Calibration 447
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Practical Recording Techniques
Recording and Mixing Pop Music for Surround 449
Panning 449
Using the Center Speaker 450
Using the LFE Channel 450
Downmixing 451
Surround Mix Delivery Format 451
Surround-Sound Mic Techniques 451
Soundfield 5.1 Microphone System 452
Delos VR2 Surround Miking Method 452
NHK Method 453
The KFM 360 Surround System 454
Five-Channel Microphone Array with Binaural Head 455
DMP Method 457
Woszcyk Technique (PZM Wedge plus Opposite-Polarity,
180-Degree Coincident-Cardioid Surround Mics) 458
Williams Five Cardioid Mic Array 459
Double MS Technique 459
Surround Ambience Microphone Array 460
Spider Microphone Array 460
The Holophone H2-PRO Surround Mic 461
Mike Sokol’s FLuRB Array 461
Stereo Pair plus Surround Pair 461
Surround Media 462
Compact Disc 462
DVD 463
Super Audio CD 466
Encoding Surround for Release on Various Formats 467
Surround Encoding for CD 467
Surround Encoding for DVD-Video 468
Surround Encoding for DVD-Audio 468
Summary of Media Formats 469
Encoding Hardware and Software for CD and
DVD-Video 469
DVD Pre-Mastering Formats 471
Dolby Units for DVD Mastering 472
20
Putting Your Music on the Web 473
Streaming versus Downloading 473
Data Compression 474
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Table of Contents
Web-Related Audio Files 475
What You Need 476
How to Upload Compressed Audio Files 478
Putting Your Music on Your Web Site 480
Putting MP3 or WMA Files on Your Site 480
Putting RealAudio Files on Your Site 482
Examples of Web-page Song Links 484
Streaming Audio from a RealServer Site 484
Liquid Audio 488
A
db or not dB 489
Definitions 489
Sound Pressure Level 490
Signal Level 490
dBm 491
dBv or dBu 492
dBV 492
Change in Signal Level 493
The VU Meter, Zero VU, and Peak Indicators 494
Balanced versus Unbalanced Equipment Levels 495
Interfacing Balanced and Unbalanced Equipment 496
Microphone Sensitivity 496
B
Optimizing Your Computer for Digital
Audio 499
Speeding Up Your Hard Drive 500
Increasing Processing Speed 502
Preventing Interruptions 504
Setting the Buffer Size 506
Other Tips 506
Optimizing MacIntosh for Audio 508
C
Introduction to SMPTE Time Code 509
How the Time Code Works 509
Time-Code Signal Details 510
Drop-Frame Mode 510
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Practical Recording Techniques
Setting Up a Time-Code System 512
How to Use SMPTE Time Code 514
Restriping Defective Code 515
Audio-for-Video SMPTE Applications 515
Synchronizing to Video 516
The Audio-Tape Synchronization Procedure 516
Using SMPTE with a Digital Audio Workstation 517
Other Time-Code Applications 519
D
Further Education 521
Books and Videos 521
The Library 521
Pro Audio Books 521
Music Books Plus 521
Focal Press 522
Amazon.com 522
Recording Magazines 522
Pro Audio Magazines 522
Consumer Audio Magazines 523
Guides, Brochures, and Other Literature 523
Guides to Recording Schools 523
The Internet 524
Recording Equipment Catalogs 525
Experience 525
E
Impedance 527
What Is Impedance? 527
I’m Connecting Two Audio Devices. Is It Important to Match Their
Impedances? What If I Don’t? 527
What About Microphone Impedance? 529
I’m Connecting a Mic to a Mixer. Is Impedance a Consideration? 529
Should I Consider Impedance When I Connect Two Line-Level
Devices? 530
Can I Connect One Source to Two or More Loads? 530
Can I Connect Two or More Sources to One Input? 530
Summary 531
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Table of Contents
Glossary 533
Index
583
CD Liner Notes
xxiii
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PREFACE
Recording is a highly skilled craft combining art and science. It requires
technical knowledge as well as musical understanding and critical listening ability. By learning these skills, you can capture a musical performance and reproduce it with quality sound for the enjoyment and
inspiration of others.
Your recordings will become carefully tailored creations of which
you can be proud. They will be a legacy that can bring pleasure to many
people for years to come.
This book is intended as a hands-on, practical guide for beginning
and intermediate recording engineers, producers, musicians—anyone
who wants to make better recordings by understanding recording equipment and techniques. I hope to prepare the reader for work in a home
studio, a small professional studio, or an on-location recording session.
Practical Recording Techniques offers up-to-date information on the
latest recording technology, such as hard-disk and memory recorders,
computer recording, keyboard and digital workstations, SMPTE and
MIDI, surround sound, and audio for the Internet. But it also guides the
beginner through the basics, showing how to make quality recordings
with the new breed of inexpensive home-studio equipment.
The first chapter answers the question, “Why do we record?” Next,
the book overviews the recording-and-reproduction chain to instill a
system concept. The basics of sound and signals are explained so that
you’ll know what you’re controlling when you adjust the controls on a
piece of recording equipment. Then advice is given on equipping a home
studio, from low budget to advanced.
Studio setup is covered next, including suggestions for improving
your studio acoustics, choosing monitor speakers, and preventing hum.
Each piece of recording equipment is explained in detail, as well as
the control-room techniques you’ll use during actual sessions. Two chapters are devoted to the technology of digital recording and MIDI sequencing. A major chapter on computer recording covers the latest ways of
creating and recording music. Two sections on remote recording cover
techniques for both popular and classical music.
xxv
Practical Recording Techniques
A special chapter explains how to judge recordings and improve
them. The engineer must know not only how to use the equipment, but
also how to tell good sound from bad.
The latest developments in recording are surround sound and audio
for the Internet. Both these topics are covered in detail in their own
chapters.
Finally five appendices explain the decibel, suggest how to optimize
your computer for digital audio, introduce SMPTE time code, suggest
further education, and explain impedance.
The CD included with this book demonstrates various topics
explained in the book. Throughout the text, references to specific CD
tracks guide the reader to relevant audio demonstrations.
Based on my work as a professional recording engineer, the book is
full of tips and shortcuts for making great-sounding recordings, whether
in a professional studio, project studio, on-location, or at home. You’ll find
many topics not covered in similar texts:
Loop-based recording
Hum prevention tips
The latest monitoring methods
Examples of mic models by type
Microphone selection guide
Tonal effects of microphone placement
Glossary of sound-quality descriptions
The latest types of digital recorders
Up-to-date coverage of computer recording
Optimizing your computer for digital audio
Documenting the recording session
Audio-for-video techniques
On-location recording
Troubleshooting bad sound; guidelines for good sound
Audio on the Web
Surround sound and DVD
xxvi
ACKNOWLEDGMENTS
Thank you to Nick Batzdorf of Recording magazine for giving me permission to draw from my “Take One” series. For my education, thank
you to the College of Wooster, Crown International, Shure Brothers Inc.,
Astatic Corporation, and all the studios I’ve worked for.
Thank you to Beth Howard, Emma Baxter, Becky Golden-Harrow,
Paul Gottehrer, and Joanne Tracy at Focal Press/Elsevier for their fine
work and support.
My deepest thanks to Jenny Bartlett for her many helpful suggestions as a layperson consultant and editor. She made sure the book could
be understood by beginners.
A note of appreciation goes to the Pat Metheny Group and Samuel
“Adagio for Strings” Barber, among many others, whose music inspired
the chapter “Music: Why You Record.”
Finally, to the musicians I’ve recorded and played with, a special
thanks for teaching me indirectly about recording.
xxvii
1
MUSIC: WHY YOU RECORD
As you learn about recording techniques for music, it’s wise to remember that music is a wonderful reason for recording.
Music can be exalting, exciting, soothing, sensuous, and fulfilling.
It’s marvelous that recordings can preserve it. As a recording engineer or
recording musician, it’s to your advantage to better understand what
music is all about.
Music starts as musical ideas or feelings in the mind and heart of its
composer. Musical instruments are used to translate these ideas and feelings into sound waves. Somehow, the emotion contained in the music—
the message—is coded in the vibrations of air molecules. Those sounds
are converted to electricity and stored magnetically or optically. The composer’s message manages to survive the trip through the mixing console
and recorders; the signal is transferred to disc or computer files. Finally,
the original sound waves are reproduced in the listening room, and
miraculously the original emotion is reproduced in the listener as well.
Of course, not everyone reacts to a piece of music the same way, so
the listener may not perceive the composer’s intent. Still, it’s amazing that
anything as intangible as a thought or feeling can be conveyed by tiny
magnetic patterns on a hard disk or by pits on a compact disc.
The point of music lies in what it’s doing now, in the present. In
other words, the meaning of “Doo wop she bop” is “Doo wop she bop.”
The meaning of an Am7 chord followed by a Fmaj7 chord is the experience of Am7 followed by Fmaj7.
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Practical Recording Techniques
Increasing Your Involvement in Music
Sometimes, to get involved in music, you must relax enough to lie back
and listen. You have to feel unhurried, to be content to sit between your
stereo speakers or wear headphones, and listen with undivided attention.
Actively analyze or feel what the musicians are playing.
Music affects people much more when they are already feeling the
emotion expressed in the song. For example, hearing a fast Irish reel when
you’re in a party mood, or hearing a piece by Debussy when you’re
feeling sensuous, is more moving because your feelings resonate with
those in the music. When you’re falling in love, any music that is meaningful to you is enhanced.
If you identify strongly with a particular song, that tells you something about yourself and your current mood. And the songs that other
people identify with tell you something about them. You can understand
individuals better by listening to their favorite music.
Different Ways of Listening
There are so many levels on which to listen to music—so many ways to
focus attention. Try this. Play one of your favorite records several times
while listening for these different aspects:
•
•
•
•
•
•
•
•
•
•
Overall mood and rhythm
Lyrics
Vocal technique
Bass line
Drum fills
Sound quality
Technical proficiency of musicians
Musical arrangement or structure
Reaction of one musician to another musician’s playing
Surprises versus predictable patterns
By listening to a piece of music from several perspectives, you’ll get
much more out of it than if you just hear it as background. There’s a lot
going on in any song that usually goes unnoticed. Sometimes when you
play an old familiar record and listen to the lyrics for the first time, the
whole meaning of the song changes for you.
2
Music: Why You Record
1
Most people react to music on the basic level of mood and rhythmic
motivation. But as a recording enthusiast, you hear much more detail
because your focus demands sustained critical listening. The same
is true of trained musicians focusing on the musical aspects of a
performance.
It’s all there for anyone to hear, but you must train yourself to hear
selectively and to focus attention on a particular level of the multidimensional musical event. For example, instead of just feeling excited
while listening to an impressive lead-guitar solo, listen to what the guitarist is actually playing. You may hear some amazing things.
Here’s one secret of really involving yourself in recorded music:
Imagine yourself playing it! For example, if you’re a bass player, listen to
the bass line in a particular record, and imagine that you’re playing the
bass line. You’ll hear the part as never before. Or respond to the music
visually—see it as you do in the movie Fantasia.
Follow the melody line and see its shape. Hear where it reaches up,
strains, and then relaxes. Hear how one note leads into the next. How
does the musical expression change from moment to moment?
There are times when you can almost touch music: some music
has a prickly texture (many transients, emphasized high frequencies); some music is soft and sinuous (sine-wave synthesizer notes,
soaring vocal harmonies); and some music is airy and spacious (lots of
reverberation).
Why Record?
Recording is a real service. Without it, people would be exposed to much
less music. They would be limited to the occasional live concert or to their
own live music, played once and forever gone.
With recordings, you can preserve a performance for thousands of
listeners. You can hear an enormous variety of musical expressions whenever you want. Unlike a live concert, a record can be played over and
over for analysis. Tapes or discs are also a way to achieve a sort of immortality. The Beatles may be gone, but their music lives on.
Records can even reveal your evolving consciousness as you grow
and change. A tape or disc stays the same physically, but you hear it differently over the years as your perception changes. Recordings are a constant against which you can measure change in yourself.
Be proud that you are contributing to the recording art—it is done
in the service of music.
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2
THE RECORDING CHAIN
Welcome to the brave new world of 21st-century recording! The digital
technologies of the past few years have given us possibilities undreamed
of just 15 years ago. This book will show you an overview of current
recording technology, help you choose the equipment that best suits your
needs, and guide you in using it to create great recordings. And it will
explain the technical jargon in plain English.
Thanks to the shift from analog to digital technology, the excitement
and satisfaction of recording are accessible to more people than ever
before. It used to take a whole roomful—or truckful—of expensive equipment to produce a good recording. But the new generation of smaller,
cheaper gear means you may be able to tuck your studio into a corner of
your bedroom or the back seat of your Toyota. As a result, many more
people are involved in the process of recording—as musicians recording
their own albums, or as engineers offering services to others.
As a recording engineer, you are a key player. Your skills help artists
realize their visions in sound. Your miking techniques capture the
vibrancy of the performance, whether it’s the shimmering overtones of a
string quartet or the sonic assault of an electric blues band. Your “post”
work in the studio—adding effects, tweaking levels, etc.—will take the
raw material of the performance and shape and blend it into a polished
musical statement. Mastering the technology by becoming fluent with the
audio tools at hand, you will produce exciting recordings that will delight
your clients and give you a real sense of pride and achievement.
5
Practical Recording Techniques
Be sure to practice what you learn in this book. There’s no substitute for hands-on experience. You might offer to record a band’s rehearsal
for free while you experiment and master the gear. Be patient, let yourself make mistakes, and above all, listen to how the sound changes when
you move a mic or tweak a knob.
Types of Recording
Let’s get started. Currently there are six main ways to record music:
1. Live stereo recording: Record with a stereo microphone or two
microphones into a recorder.
2. Live-mix recording: Pick up the musicians with several mics
plugged into a mixer. Adjust the mic levels and record the mix into
a recorder.
3. Separate multitrack recorder and mixer: Record with several mics
into a mixer, which is connected to a multitrack recorder. Each track
on the recorder contains the sound of a different instrument. After
the recording is done, you mix or combine the tracks to stereo or
surround.
4. Stand-alone Digital Audio Workstation (DAW, recorder-mixer): This
is a multitrack recorder and a mixer combined in one portable
chassis. The multitrack recording is done on a hard drive or
MiniDisc.
5. Computer DAW: This system includes a computer, recording
software, and an audio interface that gets audio into and out of
your computer. You record on the computer’s hard drive.
6. MIDI sequencing: A musician performs on a MIDI controller, such
as a piano-style keyboard or drum pads. The controller puts out a
MIDI signal, a series of numbers that indicates which keys were
pressed and when they were pressed. The MIDI signal is recorded
into computer memory by a sequencer. When you play back the
sequence, it plays the tone generators in a synthesizer or plays
samples: digital recordings of musical notes. Some recording software includes a sequencer application.
Let’s look at each type of recording in more detail.
6
The Recording Chain
2
Live Stereo Recording
This method is most commonly used to record an orchestra, symphonic
band, pipe organ, small ensemble, quartet, or soloist. The microphones
pick up the overall sound of the instruments and the concert-hall
acoustics. You might use this minimalist technique to record a folk group,
acoustic jazz group, or classical-music ensemble in a good-sounding
room.
Figure 2.1 shows the stages of this method—the links in the recording chain. Let’s look at each stage from left to right (beginning to end).
1. The musical instruments or voices make sound waves.
2. The sound waves travel through the air and bounce or reflect off the
walls, ceiling, and floor of the concert hall. These reflections add a
pleasing sense of spaciousness.
3. The sound waves from the instruments and the room reach the
microphones, which convert the sound into electrical signals.
4. The sound quality is greatly affected by mic technique. Microphone
choice and placement are critical in this method because you have
no way to adjust the sound later.
5. The signals from the microphones go to a 2-track recorder. It may be
a hard-drive recorder, CD-R burner, DVD-R burner, Flash memory
recorder, or computer hard drive. The signal changes to a pattern
stored on a medium, such as magnetic patterns on a hard disk.
During playback, the patterns on the medium are converted back
into a signal.
As the medium moves during recording, signals are stored along a
track—a path or channel on the medium containing a recorded signal.
Figure 2.1
The recording chain for live stereo recording.
7
Practical Recording Techniques
One or more tracks can be recorded on a single medium. For example, a
2-track hard-disk recording stores two tracks on hard disk, such as the
two different audio signals required for stereo recording.
6. To hear the signal you’re recording, you need a monitor system:
headphones or a stereo power amplifier and loudspeakers. You use
the monitors to judge how well your mic technique is working.
The speakers or headphones convert the signal back into sound. This
sound resembles that of the original instruments. Also, the acoustics of
the listening room affect the sound reaching the listener.
Live-Mix Recording
Now let’s look at a more complex way to record (Figure 2.2). This one is
seldom used except for live broadcasts or recordings of PA mixes.
1. You use several microphones. Each one is placed close to each instrument or singer. As a result, each mic picks up very little room
acoustics. This gives a close, clear sound that’s desirable in recorded
pop music or narration. For more clarity, you might add some
sound-absorbent material on the floor, walls, and ceiling.
2. All the mics plug into a mixer, which blends all the microphone
signals into one signal, stereo or mono. The mixer also has a volume
control for each microphone. While listening to the mixer’s signal,
you adjust the volume of each instrument to make a pleasing loudness balance.
For example, if the guitar is too quiet relative to the voice, simply
turn up the volume control for the guitar microphone until it blends well
Figure 2.2
8
The recording chain for a live-mix recording.
The Recording Chain
2
with the voice. That’s a lot easier than grouping the musicians around a
single microphone and moving the musicians until you hear a good
balance.
Many mixers let you control other aspects of sound besides volume.
You can control tone quality (bass and treble), stereo position (left, right,
or center), and effects (such as artificial reverberation, which sounds like
room acoustics). You monitor the mixer’s signal with headphones or
speakers.
3. When the mix sounds okay, you record the mixer’s output signal
with a 2-track recorder.
Separate Multitrack Recorder and Mixer
One problem with the previous setup is that you have to mix while the
musicians are playing. If you make a mistake while mixing—say, one
instrument is too quiet—the musicians have to play the song again until
you get the balance right. And if you’re recording a live gig, there’s only
one chance to perfect the mix.
The solution is to use a multitrack recorder, which records four or
more tracks. It’s as if several 2-track recorders were locked together. You
record the signal of each microphone on its own track, then mix these
recorded signals after the performance is done. You can either record a
different instrument on each track or record different groups of instruments on each track. Figure 2.3 shows the stages in this method.
1. Place microphones near the instruments.
2. Plug the mics into a mixing console: a big, sophisticated mixer.
During multitrack recording, the mixing console amplifies the weak
Figure 2.3
The recording chain for multitrack recording.
9
Practical Recording Techniques
microphone signals up to the level needed by the recorder. This
console is also used to send each microphone signal to the desired
track.
3. Record the amplified mic signals on the multitrack recorder.
You can record more instruments later on unused tracks—a process
called overdubbing. Wearing headphones, the performer listens to the
recorded tracks and plays or sings along with them. You record the performance on an unused track.
After the recording is done, you will play all the tracks through the
mixing console to mix them with a pleasing balance (Figure 2.4). Here are
the steps:
1. Play back the multitrack recording of the song several times, adjusting the track volumes and tone controls until the mix is just the way
you want it. You can add effects to enhance the sound quality. Some
examples are echo, reverberation, and compression (explained in
Chapter 10). Effects are made by signal processors that connect to
your mixer, or by software applications that are part of a recording
program.
2. Record or export your final mix on a 2-track stereo recorder (harddisk recorder, memory recorder, CD-R, DVD-R, or computer hard
drive).
Three types of a multitrack recorder are a Modular Digital Multitrack (MDM), a hard-disk recorder, and a Flash memory recorder. MDM
recording, which is done on a videocassette, can be slow: you must fastforward or rewind to the part you want to hear. In contrast, a hard drive
Figure 2.4
10
The recording chain for a multitrack mixdown.
The Recording Chain
2
and Flash memory have random access: you can instantly go to any part
of the recorded program.
Stand-Alone DAW (Recorder-Mixer)
A recorder-mixer (Figure 2.5) combines a multitrack recorder and mixer
in a single chassis. It’s relatively easy to use. Other names for a recordermixer are “stand-alone Digital Audio Workstation,” “digital multitracker,” or “portable studio.” The recorder is a hard drive, a MiniDisc
recorder, or a Flash memory card.
Most recorder-mixers have built-in effects, or they can be used with
outboard effects units. Figure 2.6 shows a small home studio setup using
a recorder-mixer and outboard effects.
Computer DAW
This low-cost system includes a computer, recording software, and an
audio interface that gets audio into and out of your computer (Figure 2.7).
Four types of audio interface are
• A sound card that plugs into a slot in the computer.
• An I/O interface (sometimes called a breakout box): a chassis with
input/output connectors, wired to your computer via a USB or
FireWire port.
• A controller or control surface: a device resembling a mixer that controls the virtual controls you see on screen. Some controllers have
input and output connectors built in.
JOG WHEEL
EDITING SCREEN
CONTROLS
FADERS
Figure 2.5
A recorder-mixer.
11
Practical Recording Techniques
Figure 2.6
A small home studio with a recorder-mixer and outboard effects.
MONITOR
HARD
DRIVE
PCI SLOT, USB PORT,
OR FIREWIRE PORT
COMPUTER
KEYBOARD
ALESIS
FIREPORT
I/O INTERFACE
(BREAKOUT BOX)
SOUND CARD
MOUSE
CONTROLLER WITH I/O
AUDIO INTERFACES (CHOOSE ONE)
Figure 2.7
software.
12
Computer with a choice of audio interface and recording/editing
The Recording Chain
2
• A FirePort, a device by Alesis that accepts an Alesis-formatted hard
drive with audio recordings on it, and converts the audio files to a
signal sent via a FireWire connection to your computer.
Using the recording software, you perform these operations:
1. Record music on the computer’s hard drive.
2. Edit the tracks to fix mistakes or to copy/move song sections.
3. Mix the tracks with a mouse or controller by adjusting virtual controls that appear on your computer screen.
You might also assemble a song from samples or from loops.
Samples are recordings of single notes of various instruments. Loops are
repeating musical patterns.
MIDI Sequencing
Like a player piano, MIDI sequencing records your performance gestures
rather than audio. Figure 2.8 shows the process.
1. Play music on a MIDI controller, such as a piano-style keyboard,
drum machine pads, or breath controller.
2. As you play the controller, it sends a MIDI signal from its MIDI OUT
connector. This signal is a string of numbers—computer code—that
tells which keys you pressed, when you pressed them, how fast you
pressed them, and so on. In other words, the MIDI signal represents
your performance gestures. It’s not an audio signal.
3. The MIDI signal goes to a synthesizer or sound module, which
might be part of a computer sound card. In these devices are tone
Figure 2.8
MIDI sequencing system.
13
Practical Recording Techniques
generators that create musical sounds, such as a bass, piano, or
drums. The MIDI signal plays the tone generators. You hear them
with speakers or headphones.
The MIDI signal could also drive a drum machine or sampler. They
contain samples, which are recordings in computer memory of single
notes played by real musical instruments. The MIDI signal plays the
samples—a process called wavetable synthesis. Samples are actually
small wav files or aiff files.
4. The MIDI signal of the notes you play also goes to a sequencer—a
device that records the MIDI signal. Sequencers come in three forms:
a circuit built into a stand-alone synthesizer, a stand-alone sequencer
device, or a computer sequencer program that records MIDI
sequences on a hard drive.
5. When you play the sequencer recording, it activates the sound generators or samples to play the same notes you played. You can edit
the sequencer recording; for example, fix wrong notes, change the
instrument sounds without having to redo the performance, or
change the tempo without changing the pitch.
MIDI/digital-audio software lets you record MIDI sequences and
digital audio on hard disk. First record a few tracks of MIDI sequences
onto hard disk, then add audio tracks (lead vocal, sax solo, or whatever).
All these elements will stay synchronized.
Pros and Cons of Each Method
Live stereo recording is simple, cheap, and fast. But it usually sounds too
muddy with rock music, and you must adjust balances by moving musicians. It can work well with classical music, and sometimes with folk or
acoustic jazz music.
Live-mix recording is fairly simple and quick. However, loud instruments might sound distant in the recording because their sound “leaks”
into distant mics. And if the mix or performance has mistakes, the band
has to re-record the entire song. Also, the live sound of the band can make
it hard to hear the monitored sound clearly.
Multitrack recording has many advantages. You can punch-in—fix
a musical mistake by recording a new, correct part over the mistake.
You can overdub—record one instrument at a time. This reduces leakage
14
The Recording Chain
2
and gives a tighter sound. Also, you can postpone mixing decisions
until after the performance. Then you can monitor the mix in quiet surroundings. This method is more complex and expensive than live-mix
recording.
If you use a separate multitrack recorder and mixer, each component can be used independently. For example, you might do an onlocation live recording with just the recorder, or do a PA job with just
the mixer. Or, if you already have a mixer, all you need to buy is a
recorder. This system is a little difficult to set up because you need to
connect cables between the mixer and recorder and between the mixer
and outboard effects units.
A stand-alone DAW (recorder-mixer) is easy to use because it is a
single portable chassis that includes most of your studio equipment:
recorder, mixer, effects, and often a CD burner. It doesn’t require cables
except for mics, instruments, and monitor speakers. High-end units let
you edit the music. They also have automated mixing—memory chips in
the mixer remember your mixdown settings—and reset the mixer accordingly the next time you play back the recording.
A computer DAW is inexpensive, powerful, and flexible. It lets you
do sophisticated editing and automated mixing. Several plug-in (software) effects are included, and you can purchase and install other plugins. Recording software can be updated at little cost. As for drawbacks,
computers can crash and can be difficult to set up and optimize for audio
work.
MIDI sequencing lets you record musical parts by entering
notes slowly or one at a time if necessary, then play the performance
at a regular tempo. You can edit notes to correct mistakes and change
the instrument sounds after recording the performance. However, you
are limited to the sounds of samples and sound modules unless you use
MIDI/digital-audio software, which lets you add miked instruments to
the mix.
The enclosed CD contains samples of several types of recordings.
Play CD tracks 1 and 2. Track 2 demonstrates:
•
•
•
•
•
Live stereo recording—orchestra
Live stereo recording—rock group
Live mix recording—jazz group
Multitrack recording—pop group
MIDI sequencing—synthesizer funk
15
Practical Recording Techniques
Editing/Mastering
No matter which recording method you use, eventually you’ll mix all
your songs to a 2-track recorder. Then you may want to edit those
recorded mixes. Editing is the process where you remove noises and
count-offs between songs, put the songs in the desired order, and put a
few seconds of silence between songs. This is done with a computer and
editing software (a DAW, Figure 2.7).
The last step is to copy the edited program to CD-R or DVD-R.
There’s your final product, ready to duplicate.
Quality Levels of Recording Formats
Here is a list of various recording formats from lowest sound quality to
highest:
1. Cassette (becoming obsolete): Has some hiss, distortion, and wow
and flutter that can make wobbly pitch.
2. Analog tape recorded at 7–1/2 ips or with narrow width tape (1/4
inch, 1/2-inch): This medium is becoming obsolete. Analog tape
recordings can sound very good but have some tape hiss.
3. MiniDisc: This format uses data compression that degrades the
sound quality slightly. Details are in Chapter 9.
4. Digital recording at 16 bits, 44.1 kHz: This is CD quality. Media that
offer 16-bit recording are DAT, CD, MDM, hard disk, and Flash
memory.
5. Digital recording at 24 bits, 44.1 kHz: Media that offer 24-bit recording are DVD, some MDM models, hard disk, and Flash memory.
6. Digital recording at 24 bits, 96 kHz, or 192 kHz: Media that offer this
format are DVD, hard disk, and Flash memory. Another option is
high-speed analog tape recording, perhaps with noise reduction.
Another choice is Super Audio CD (SACD). It is considered by many
to be state-of-the-art, as is 24-bit/192 kHz recording.
7. MIDI: If the sequencer recording is played by the same sound
modules or samplers that were used during recording, it sounds
exactly like the original performance. MIDI sequencer recordings
reach the public on CD, DVD, or SACD media.
No matter what type of recording you do, each stage contributes to
the sound quality of the finished recording. A bad-sounding master CD
16
The Recording Chain
2
can be caused by any weak link: low-quality microphones, bad mic placement, improperly set mixer controls, and so on. A great-sounding recording results when you get every stage right. This book will help you reach
that goal.
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3
SOUND, SIGNALS, AND
STUDIO ACOUSTICS
When you make a recording, you deal with at least two kinds of invisible energy: sound waves and electrical signals. For example, a microphone converts sound into a signal. A signal is a varying voltage that
carries information. In our case, it’s musical information.
This chapter covers some characteristics of sound and audio signals.
These facts will help you work with room acoustics, and will help you
know what’s going on inside your mixer as you adjust the controls. With
this knowledge you can make better recordings.
Sound Wave Creation
To produce sound, most musical instruments vibrate against air molecules, which pick up the vibration and pass it along as sound waves.
When these vibrations strike your ears, you hear sound.
To illustrate how sound waves are created, imagine a vibrating
speaker cone in a guitar amp. When the cone moves out, it pushes the
adjacent air molecules closer together. This forms a compression. When
the cone moves in, it pulls the molecules farther apart, forming a
rarefaction. As shown in Figure 3.1, the compressions have a higher
19
Practical Recording Techniques
Figure 3.1
A sound wave.
pressure than normal atmospheric pressure; the rarefactions have a
lower pressure than normal.
These disturbances pass from one molecule to the next in a springlike motion—each molecule vibrates back and forth to pass the wave
along. The sound waves travel outward from the sound source at 1130
feet per second (344 meters per second), which is the speed of sound in
air at room temperature.
At some receiving point, such as an ear or a microphone, the air pressure varies up and down as the disturbances pass by. Figure 3.2 is a graph
showing how sound pressure varies with time, like a wave. The high
point of the graph is called a peak; the low point is called a trough. The
horizontal center line of the graph is normal atmospheric pressure.
Sound waves tend to spread out as they travel away from the source.
The compressions and rarefactions move out as expanding spheres. As
the spherical waves expand, the sound pressure spreads over a larger
area, so the pressure becomes weaker with distance from the source. This
means that the farther you are from a sound source, the quieter the sound.
Specifically, the sound pressure halves (drops 6 decibels; dB) each time
the distance from the source doubles. This phenomenon is called the
inverse square law.
20
Sound, Signals, and Studio Acoustics
3
Figure 3.2
Caption: Sound pressure vs. time of one cycle of a sound wave.
Figure 3.3
Three cycles of a wave.
Characteristics of Sound Waves
Figure 3.3 shows three waves in succession. One complete vibration from
normal to high to low pressure and back to the starting point is called
one cycle. The time it takes to complete one cycle—from the peak of one
wave to the next—is called the period of the wave. One cycle is one period
long.
Amplitude
The height of the wave is its amplitude. Loud sounds have high amplitudes (big pressure changes); quiet sounds have low amplitudes (small
pressure changes). Play track 3 on the enclosed CD to hear an example.
Frequency
The sound source (in this case, the guitar-amp loudspeaker) vibrates back
and forth many times a second. The number of cycles completed in one
second is called frequency. The faster the speaker vibrates, the higher the
frequency of the sound. Frequency is measured in hertz (Hz), which
21
Practical Recording Techniques
stands for cycles per second. One thousand hertz is called one kilohertz,
abbreviated kHz.
The higher the frequency, the higher the perceived pitch of the
sound. Low-frequency tones have a low pitch (like low E on a bass, which
is 41 Hz). High-frequency tones have a high pitch (like four octaves above
middle C, or 4186 Hz). Track 4 on the enclosed CD illustrates this. Doubling
the frequency raises the pitch one octave.
Children can hear frequencies from 20 Hz to 20 kHz, and most adults
with good hearing can hear up to 15 kHz or higher. Each musical instrument produces a range of frequencies, say, 41 Hz to 9 kHz for a string bass,
or 196 Hz to 15 kHz for a violin.
Wavelength
When a sound wave travels through the air, the physical distance from
one peak (compression) to the next is called a wavelength (refer to Figure
3.1). Low-pitched sounds have long wavelengths (several feet); highpitched sounds have short wavelengths (a few inches or less). Wavelength is the speed of sound divided by frequency. So the wavelength of
a 1000-Hz wave is 1.13 feet (0.344 m); 100 Hz is 11.3 feet (3.44 m), and
10 kHz is 1.35 inches (3.45 cm).
Phase and Phase Shift
The phase of any point on the wave is its degree of progression in the
cycle—the beginning, the peak, the trough, or anywhere between. Phase
is measured in degrees, with 360 degrees as one complete cycle. The
beginning of a wave is 0 degrees; the peak is 90 degrees (one-quarter
cycle), and the end is 360 degrees. Figure 3.4 shows the phases of various
points on the wave.
Figure 3.4
22
The phases of various points on a wave.
Sound, Signals, and Studio Acoustics
3
If there are two identical waves traveling together, but one is
delayed with respect to the other, there is a phase shift between the two
waves. The more delay, the more phase shift. Phase shift is measured in
degrees. Figure 3.5 shows two waves separated by 90 degrees (onequarter of a cycle) of phase shift. The dashed wave lags the solid wave
by 90 degrees.
If you combine two identical sound waves, such as a sound and its
reflection off a wall, the peaks of the two waves add together at certain
points in the room. This doubles the sound pressure or amplitude, creating areas of louder sound at certain frequencies.
Phase Interference
When there is a 180-degree phase shift between two identical waves, the
peak of one wave coincides with the trough of another (Figure 3.6). If
these two waves are combined, they cancel out. This phenomenon is
called phase cancellation or interference.
Suppose you have a signal with a wide range of frequencies, such
as the singing voice. If you delay this signal and combine it with the
original undelayed signal, some frequencies will be 180 degrees out of
phase and will cancel. This makes a hollow, filtered tone quality.
Here’s an example of how this can happen. Suppose you’re recording a singer/guitarist with one mic near the singer and another mic near
the guitar. Both mics pick up the singer. The singer’s mic is close to the
mouth, and you hear it with no delay in the signal. The guitar mic is
farther from the mouth, so its voice signal is delayed. When you mix the
two mics, you often hear a colored tone quality caused by phase cancellations between the two mics.
Suppose you’re recording a stage play with a mic on a short stand
on the floor. The mic picks up the direct sound from the actors, but it also
Figure 3.5
Two waves that are 90 degrees out of phase.
23
Practical Recording Techniques
AMPLITUDE
TIME
AMPLITUDE
DELAY CAUSING
A 180-DEGREE
PHASE SHIFT
TIME
AMPLITUDE
SUM OF BOTH WAVES ABOVE
TIME
Figure 3.6 Phase interference: Adding two waves that are out of phase cancels
the sound at that frequency.
picks up delayed reflections off the floor. Direct and delayed sounds
combine at the mic, causing phase cancellations. You hear it as a hollow,
filtered sound that changes when the actor walks while talking.
Harmonics
The type of wave shown in Figure 3.2 is called a sine wave. It is a pure
tone of a single frequency, like a signal from a tone generator. In contrast,
most musical tones have a complex waveform, which has more than one
frequency component. All sounds are combinations of sine waves of different frequencies and amplitudes. Figure 3.7 shows sine waves of three
frequencies combined to form a complex wave.
The lowest frequency in a complex wave is called the fundamental
frequency. It determines the pitch of the sound. Higher frequencies in the
complex wave are called overtones or upper partials. If the overtones are
multiples of the fundamental frequency, they are called harmonics. For
example, if the fundamental frequency is 200 Hz, the second harmonic is
400 Hz, and the third harmonic is 600 Hz.
The harmonics and their amplitudes help determine the tone quality
or timbre of a sound, and help to identify the sound as a trumpet, piano,
organ, voice, etc. Play CD track 5.
24
Sound, Signals, and Studio Acoustics
Figure 3.7
waveform.
3
Adding fundamental and harmonic waveforms to form a complex
Noise (such as tape hiss) contains a wide band of frequencies and
has an irregular, nonrepeating waveform.
Envelope
Another characteristic that identifies a sound is its envelope. When a note
sounds, it doesn’t last forever—it rises in volume, lasts a short time, then
falls back to silence. This rise and fall in volume of one note is called the
note’s envelope. The envelope connects the peaks of successive waves
that make up a note. Each musical instrument has a different envelope.
Most envelopes have four sections: attack, decay, sustain, and
release (see Figure 3.8). During the attack, a note rises from silence to its
maximum volume. Then it decays from maximum to some midrange
level. This middle level is the sustain portion. During release, the note
falls from its sustain level back to silence.
Percussive sounds, such as drum hits, are so short that they have
only a rapid attack and decay. Other sounds, such as organ or violin
25
Practical Recording Techniques
Figure 3.8
The four sections of the envelope of a note.
notes, last longer. They have slower attacks and longer sustains. Guitar
plucks and cymbal crashes have quick attacks and slow releases. They hit
hard then fade out slowly. Play CD track 6.
You can shorten a guitar string’s decay or ringing by damping the
string with the side of your hand. You can press a blanket against a kick
drum head to damp the decay and get a tighter sound.
Behavior of Sound in Rooms
Because most music is recorded in rooms, you need to understand how
room surfaces affect sound.
Echoes
Musical instruments make sound waves that travel outward in all directions. Some of the sound travels directly to your ears (or to a microphone)
and is called direct sound. The rest strikes the walls, ceiling, floor, and
furnishings of the recording room. At those surfaces, some of the sound
is absorbed, some is transmitted through the surface, and the rest is
reflected back into the room.
Because sound waves take time to travel (moving at about 1 foot per
millisecond), the reflected sound reaches you after the direct sound. The
reflection repeats the original sound after a short delay. If the sound is
delayed about 50 msec or more, we call it an echo (Figure 3.9). In some
concert halls we hear single echoes; in small rooms we often hear a short,
rapid succession of echoes called flutter echoes. You can detect them by
clapping your hand next to a wall. Flutter echoes happen when sound
bounces back and forth between two parallel walls.
26
Sound, Signals, and Studio Acoustics
3
Figure 3.9 Echoes. (A) Echo formation. (B) Intensity vs. time of direct sound
and its echoes.
Reverberation
Sound reflects many times from all the surfaces in the room. These reflections sustain the sound of each note the musician plays. This persistence
of sound in a room after the original sound has stopped is called reverberation (reverb). For example, reverberation is the sound you hear just
after you shout in an empty gymnasium. The sound of your shout stays
in the room and gradually dies away (decays). Play CD track 10 to hear
echoes and reverberation.
Reverb is hundreds of echoes that gradually get quieter. The echoes
follow each other so rapidly that they merge into a single continuous
sound. Eventually, the room surfaces completely absorb the echoes. The
timing of the echoes is random, and the echoes increase in number as
they decay. Figure 3.10 shows how reverberation develops in a recording
room.
Reverberation is a continuous fade-out of sound (HELLO-O-O-o-o),
while an echo is a discrete repetition of a sound (HELLO hello hello
hello).
27
Practical Recording Techniques
Figure 3.10 Reverberation. (A) Multiple sound reflections create reverberation.
(B) Intensity vs. time of direct sound, early reflections, and reverberation.
Reverberation time (RT60) is the time it takes for reverb to decay
60 dB. Too long a reverb time makes a recording sound distant, muddy,
and washed-out. That’s why pop-music recordings are usually made in
a fairly “dead” or nonreverberant studio, which has an RT60 of about 0.4
second or less. In contrast, classical music is recorded in “live,” reverberant concert halls (RT60 about 1 to 3 seconds) because we want to hear
reverb with classical music—it’s part of the sound.
Reverberation comes to you from every direction because it is a
pattern of many sound reflections off the walls, ceiling, and floor. Because
we can tell where sounds come from, we can distinguish between the
direct sound of an instrument coming to us from a single location and
the reverberation coming to us from everywhere else. So we can ignore
the reverb and concentrate on the sound source. In fact, we normally are
not aware of reverberation.
But suppose you put a mic next to your ears, record an instrument
in that room, and play back the recording. You’ll hear a lot more reverb
than what you heard live. What’s going on? The reverb you recorded is
28
Sound, Signals, and Studio Acoustics
3
not all around you. Instead, it’s all up front between the speakers. So it’s
more audible; you can’t discriminate against the reverb spatially. To
reduce the amount of reverb in your recordings, you need to place mics
close to instruments, and maybe add some sound-absorbing materials to
the room.
Diffusion
When sound waves strike and reflect off a very bumpy or convex surface,
they spread out or diffuse. This diffusion can be used to weaken sound
reflections. Sound waves also spread out when they travel through a
small opening.
Leakage
Sound from an instrument travels to the nearest mic, and also “leaks”
into the mics intended for other instruments (Figure 3.11). This overlap
of an instrument’s sound into the mic of another instrument is called
leakage (or bleed or spill).
It’s very important to minimize leakage—to ensure that each mic
picks up only its intended instrument. Suppose that you’re miking a
drum set and an acoustic piano. As the musicians play, you monitor
what the mics pick up. When you turn up just the drum mics, the drums
sound close-up or “tight.” But when you also turn up the piano mic, the
drum sound becomes distant or muddy. That’s because the piano mic
picks up drum leakage at a distance. Play CD track 11 to hear an example
of leakage.
Figure 3.11 Example of leakage. The piano mic picks up leakage from the
drums, changing the close drum sound to distant.
29
Practical Recording Techniques
How to Tame Echoes, Reverb, and Leakage
Echoes, reverb, and leakage can make your recordings sound mushy and
distant. There are two ways to prevent these problems: with recording
techniques and with acoustic treatment.
Controlling Room Problems with Recording
Techniques
Sometimes you can make clean recordings in an ordinary room—such as
a club, living room, or basement—if you follow these suggestions:
• Mike close. Place each mic 1 to 6 inches from each instrument or
voice. Then the mics will hear more of the instruments and less of
the room reflections. You might want to use mini mics, which attach
directly to instruments.
• Use directional mics—cardioid, supercardioid, or hypercardioid—
which reject room acoustics.
• Record bass guitar and synth directly with a guitar cord or a direct
box. Because you omit the microphone, you pick up no room
acoustics. To get a good sound when recording electric guitar direct,
record off the effects boxes or use a guitar-amp simulator.
• Overdub instruments one at a time rather than recording them all
at once. You’ll pick up a much cleaner sound. However, this loses
the emotional interaction that occurs when all the musicians play
together. You might record all the loud instruments at once: drums,
bass, and electric guitar. Then overdub the quiet instruments:
acoustic guitars, sax, piano, vocals.
• Record in a large room. This lets you spread the musicians farther
apart, and weakens the sound reflections from the walls into the
mics.
Controlling Room Problems with Acoustic Treatments
When should you apply acoustic treatment to a room or build a studio?
• You clap your hands next to a wall and you hear flutter echoes (a
fluttering sound). These are caused by sounds bouncing back and
forth between hard parallel walls.
30
Sound, Signals, and Studio Acoustics
3
• Your studio is a very live environment, such as a garage or concreteblock basement, so you hear too much room reverberation.
• Your studio is very small.
• You hear outside noises in your recordings.
• Bass-guitar amps and monitor speakers sound boomy.
• You want the freedom to mike several feet away without picking up
noise or excess room reverb.
• You hear a lot of leakage in the mic signals.
If these conditions apply, check out the following suggestions on
upgrading the acoustics of your studio.
Reverb and echoes are caused by sound reflections off room surfaces. So any surface that is highly sound-absorbent helps to reduce those
problems.
To absorb high frequencies, use porous materials such as convoluted
(bumpy) foam mattresses. They can be highly flammable, so cover them
with flame-retardant treatment (such as at www.rosebrand.com). Nail or
glue them to the walls, or mount them on frames. Thick foam works
better than thin. Four-inch foam on the wall absorbs frequencies from
about 200 to 800 Hz and up, depending on the angle at which sound
strikes the foam. Leave some space between the foam panels. This helps
to diffuse or spread out the sound in the room (Figure 3.12). Don’t overdo
the foam padding. A stuffed, dead room is uncomfortable to play in. Keep
some reflections because they add “air” and liveliness to the sound.
Other high-frequency absorbers are sleeping bags, moving blankets,
carpeting, curtains, and fiberglass insulation covered with muslin or
burlap. If possible, space these materials several inches from the wall. The
spacing helps them absorb mid-bass frequencies. A wide-range absorber
is 4-inch pressed fiberglass board (Owens-Corning Type 703, 3 lb/ft3)
covered in muslin or burlap.
Start with just a little absorption behind or above the musician
you’re recording. Add more absorbers, a few at a time, until your recordings sound as dead as you wish.
To absorb low frequencies, you can make bass traps. Here are four
types:
1. Resonant tube trap: Take a 35- to 55-gallon rubber trashcan, stuff it
with fiberglass insulation (wear a dust mask and gloves), and cover
the open end with muslin or canvas. This tube trap absorbs frequencies near 1130/2H, where H is the height of the trashcan in feet.
31
Practical Recording Techniques
MONITORS
MIXER
WEDGE-SHAPED
FOAM REDUCES
REVERB AND
FLUTTER ECHOES
TUBULAR BASS TRAPS
REDUCE STANDING WAVES,
ABSORB LOWS
PLACE THEM
1/4 WAVELENGTH
FROM WALL
UNEQUAL ROOM DIMENSIONS
REDUCE STANDING WAVES
PRESSED FIBERGLASS
INSULATION BOARDS
ACROSS CORNERS
REDUCE STANDING WAVES
Figure 3.12
DIFFUSORS REDUCE
FLUTTER ECHOES
INSULATION-FILLED
CORNER BEHIND AN
OPEN LATTICE IS
ANOTHER TYPE OF
BASS TRAP
Acoustic treatments.
For example, a 3-foot-high trashcan absorbs 188 Hz. Placement is not
critical.
2. Frictional tube trap: Make a 2-foot-diameter canvas bag, 8 feet tall,
and fill it with fiberglass insulation. Hang one bag a few feet out
from each room corner (Figure 3.12). The distance should be
1130/4F, where F is the frequency in hertz that you want to absorb.
For example, to absorb 80 Hz, hang the bag 3.5 feet out from a room
corner. (Thanks to David Moulton for those ideas.)
3. Lattice: Build a 3-foot-wide flat lattice frame of wood slats, the same
height as the ceiling (Figure 3.12). Cover the frame with muslin or
burlap. Put the frame diagonally across a room corner and fill the
corner with R-30 insulation. Leave the foil on, foil side out toward
the room. Put one assembly in each corner. (Thanks to Chips Davis
for this idea.)
4. Insulation panel: Get 8 pieces of 2-foot ¥ 4-foot ¥ 4-inch rigid fiberglass insulation, type 705, from an insulation supplier. Cover each
piece with muslin or burlap to contain the fibers. Place a piece across
each room corner with the 2-foot edge touching the floor. Stack two
32
Sound, Signals, and Studio Acoustics
3
panels to make them 8 feet high. (Thanks to Ethan Winer for this
idea.)
There are other ways to absorb bass. Wood paneling works well. It
also helps to open closet doors and place couches and books a few inches
from the walls. In a basement studio, nail acoustic tile to the ceiling joists
with fiberglass insulation in the air space between tiles and ceiling.
You may not need any bass traps if you don’t put any bass into the
room. For example, don’t turn up the bass-guitar amp—just record the
bass direct and have the musicians wear headphones to hear the bass.
Controlling Standing Waves
Let’s look at another acoustic problem: standing waves. If you play an
amplified bass guitar through a speaker in a room, and do a bass run up
the scale, you may hear some notes that boom out in the room. The room
is resonating at those frequencies. These resonance frequencies, which are
strongest below 300 Hz, occur in patterns called “standing waves.” They
can give a tubby or boomy coloration to musical instruments and monitor
speakers.
Room resonances are worst in a cubical room. They are less of a
problem if the room’s length, width, and height are not multiples of each
other. Table 3.1 shows several room dimensions in feet that reduce
boomy-sounding standing waves.
For example, if the room width is 9.1 feet, and the ceiling is 8 feet
high, the length should be 11.1 feet for best reduction of boominess.
Try to record in a large room because the room resonance frequencies are likely to be below the musical range. Use bass traps to absorb
room resonances. Contrary to popular opinion, nonparallel walls don’t
prevent standing waves.
Making a Quieter Studio
The following tips will keep noises out of your recordings:
• Consider having the studio in a basement, because the earth blocks
noises from the outside. The furnace or air-conditioning might be a
problem, however.
• Turn off appliances and telephones while recording.
• Pause for ambulances and airplanes to pass.
33
Practical Recording Techniques
Table 3.1 Room dimensions in feet to reduce
standing waves
Height
8
8
8
8
8
8
8
8
10
10
10
10
10
10
10
10
•
•
•
•
•
•
•
•
Width
Length
9.1
9.4
10.1
10.2
11.6
11.8
12.8
13.0
11.4
11.7
12.6
12.8
14.5
14.7
16.0
16.2
11.1
11.8
11.3
12.3
16.8
13.6
18.6
21.0
13.9
14.7
14.1
15.4
21.0
17.0
23.3
26.2
Close windows. Consider covering them with thick plywood.
Close doors and seal with towels.
Remove small objects that can rattle or buzz.
Weather-strip doors all around, including underneath. (Leave the
doors open for ventilation when not recording.)
Replace hollow doors with solid doors.
Block openings in the room with thick plywood and caulking.
Put several layers of plywood and carpet on the floor above the
studio, and put insulation in the air space between the studio ceiling
and the floor above.
Place microphones close to instruments and use directional microphones. This won’t reduce noise in the studio, but it will reduce
noise picked up by the microphones.
When building a new studio, you might want to make the walls of
plastered concrete block because massive walls reduce sound transmission, or make the walls of gypsum board and staggered studs. Nail
34
Sound, Signals, and Studio Acoustics
Figure 3.13
3
Staggered-stud construction to reduce noise transmission.
gypsum board to 2 ¥ 4 staggered studs on 2 ¥ 6 footers as shown in Figure
3.13. Staggering the studs prevents sound transmission through the
studs. Fill the air space between walls with insulation.
The ideal home-recording room for pop music is a large, well-sealed
room with optimum dimensions. This room is in a quiet neighborhood.
It should have some soft surfaces (carpet, acoustic-tile ceiling, drapes,
couches), and some hard vibrating surfaces (wood paneling or gypsum
board walls on studs).
Your home studio may not need acoustic treatment. Do some trial
recordings to find out. But if your room could stand some improvement,
the suggestions above should point you in the right direction.
For better results and a more professional appearance, consider
buying some acoustic treatments from the following companies. Their
Web sites are tubetrap.com, realtraps.com, acousticalsolutions.com, primacoustic.com, auralex.com, acousticsfirst.com, wallmate.net, illbrucksonex.com, rpginc.com, and fstechnologies.com. Flame-retardant
treatment for blankets and curtains is at www.rosebrand.com.
Signal Characteristics of Audio Devices
When a microphone converts sound to electricity, this electricity is called
the signal. It has the same frequency and the same amplitude changes as
the incoming sound wave.
When this signal passes through an audio device, the device may
alter the signal. It might change the level of some frequencies or add
unwanted sounds that are not in the original signal. Let’s look at some
of these effects.
35
Practical Recording Techniques
Frequency Response
Suppose you have an audio device—a mic, mixer, effects unit, recorder,
or speaker. You send a musical signal through the device. Usually the
music contains some high and some low frequencies.
The device might respond differently to different frequencies. It
might amplify the low notes and weaken the high notes. You can graph
how the device responds to different frequencies by plotting its output
level versus frequency. This graph is called a frequency response (Figure
3.14). The level in the graph is measured in dB, while frequency is
measured in Hz. Generally, 1 dB is the smallest change in loudness
that we can hear.
Suppose the level is the same at all frequencies. Then the graph
forms a horizontal straight line and is called a “flat frequency response”
(Figure 3.15). All the frequencies are reproduced at an equal level. In other
words, the device passes all the frequencies without changing their relative levels. You get out the same amount of bass and treble that went in.
A flat response does not affect the tonal balance of the incoming sound.
Many audio devices do not have a flat response across the audio
band from 20 to 20,000 Hz. They have a limited range of frequencies that
can be reproduced at an equal level (within a tolerance, such as ± 3 dB).
In Figure 3.14, the frequency response shown by the solid line is 50 to
12,000 Hz ± 3 dB. That means the audio device passes all frequencies from
50 to 12,000 Hz at a nearly equal level—within 3 dB. It reproduces low
sounds and high sounds equally well. The response is down 3 dB at 50
and 12,000 Hz, and is up 3 dB at 5000 Hz.
Figure 3.14
36
An example of a frequency response.
Sound, Signals, and Studio Acoustics
Figure 3.15
3
A flat frequency response.
Usually, the more extended or “wide” the frequency range is, the
more natural and real the recording sounds. A wide, flat response gives
accurate reproduction. A frequency response of 200 to 8000 Hz (± 3 dB) is
narrow (poor fidelity); 80 to 12,000 Hz is wider (better fidelity), and 20 to
20,000 Hz is widest (best fidelity). Play CD track 7.
Also, the flatter the frequency response, the greater the fidelity or
accuracy. A response deviation of ± 3 dB is good, ± 2 dB is better, and ± 1
dB is excellent. There are exceptions to this statement, which we’ll look
at in Chapter 10 in the section on equilizers.
When you turn a bass or treble knob on your guitar amp, mixer EQ,
or stereo, you’re changing the frequency response. If you turn up the bass,
the low frequencies rise in level. If you turn up the treble, the high frequencies are emphasized. The ear interprets these effects as changes in
tone quality—warmer, brighter, thinner, duller, and so on.
Figure 3.14 shows a non-flat frequency response. Toward the right
side of this line, the response at high frequencies “rolls off” or declines.
This shows that the upper harmonics are weak. The result is a dull sound.
Toward the left side, the response at low frequencies rolls off. This means
the fundamentals are weakened and the result is a thin sound.
The frequency response of an audio device might be made non-flat
on purpose. For example, you might cut low frequencies with an
equalizer to reduce breath pops from a microphone. Also, a microphone
may sound best with a non-flat response, such as boosted high frequencies that add presence and sizzle.
37
Practical Recording Techniques
Noise
Noise is another characteristic of audio signals. Every audio component
produces a little noise—a rushing sound like wind in trees. Noise in a
recording is undesirable unless it’s part of the music.
You can make noise less audible by keeping the signal level in a
device relatively high. If the level is low, you have to turn up the listening volume in order to hear the signal well. Turning up the volume of the
signal also turns up the volume of the noise, so you hear noise along with
the signal. But if the signal level is high, you don’t have to turn up the
listening level as much. Then the noise remains in the background.
Distortion
If you turn up the signal level too high, the signal distorts and you hear
a gritty, grainy sound or clicks. This type of distortion is sometimes called
“clipping,” because the peaks of the signal are clipped off so they are flattened. To hear distortion, simply record a signal at a very high recording
level (with the meters going well into the red area) and play it back. Play
CD track 9. Digital recorders also produce quantization distortion at very
low signal levels.
Optimum Signal Level
You want the signal level high enough to cover up the noise, but low
enough to avoid distortion. Every audio component works best at a
certain optimum signal level, and this is usually indicated by a 0 on a
meter or lights that show the signal level.
Figure 3.16 shows the range of signal levels in an audio device. At
the bottom is the noise floor of the device—the level of noise it produces
with no signal. At the top is the distortion level—the point at which the
signal distorts and sounds grungy. In between is a range in which the
signal sounds clean. The idea is to maintain the signal around the 0 point
on the average. With digital recorders, however, “0” is the maximum
undistorted level.
Signal-to-Noise Ratio
The level difference in decibels between the signal level and the noise
floor is called the “signal-to-noise ratio” or S/N (see Figure 3.16). The
38
Sound, Signals, and Studio Acoustics
Figure 3.16
3
The range of signal levels in an audio device.
higher the S/N, the cleaner the sound. An S/N of 60 dB is fair, 70 dB is
good, and 80 dB or greater is excellent. Play CD track 8.
To illustrate S/N, imagine a person yelling a message over the sound
of a train. The message yelled is the signal; the noise is the train. The
louder the message, or the quieter the train, the greater the S/N. And the
greater the S/N, the clearer the message.
Headroom
The level difference in decibels between the normal signal level and the
distortion level is called “headroom” (see Figure 3.16). The greater the
headroom, the greater the signal level the device can pass without
running into distortion. If an audio device has a lot of headroom, it can
pass high-level peaks without clipping them.
You want to set your mixer controls so that the signal has some headroom, is well above the noise floor, and is below distortion. Here’s how.
During recording:
1. Set master faders and group faders to 0 (the shaded portion of fader
travel).
2. Set one musician’s mixer fader to 0.
3. Have the musician play the loudest part of the song.
4. Adjust the input trim to set the recording level to peak at about
-3 dBFS maximum.
5. Repeat for the other faders and instruments.
39
Practical Recording Techniques
During mixdown:
1. Set master faders and group faders to 0 (about three-quarters up).
2. Set up a mix with the channel faders.
3. Keeping the master and group faders near 0, adjust the channel
faders’ levels so that the mixer’s stereo meters peak around 0. (The
more faders in use, the lower the fader levels should be.)
At these settings, the signal levels in the mixer should be just about right.
The signal should have no audible noise or distortion, and the mixer
should have enough headroom so that loud peaks won’t distort.
40
4
EQUIPPING YOUR STUDIO
You want to set up a recording system that’s affordable, easy to use, and
sonically excellent. With today’s wide array of user-friendly sound tools,
you can do just that. This chapter is a guide to equipment for a recording studio: what it does, what it costs, and how to set it up.
In this chapter we’ll examine:
•
•
•
•
•
•
Equipment and costs for budget studios
Equipment for higher-end studios
Details of each piece of equipment
Cables and connectors
Simple acoustic treatments
Preventing hum and radio frequency interference
What is the bare-bones equipment you need to crank out a decent
demo CD? How much does it cost? Thanks to the new breed of affordable equipment, you can put together a complete home recording studio
for under $1200. That includes powered speakers, mics, recording software, and a sound card.
First you should know the general process for recording popular
music:
41
Practical Recording Techniques
1. Plug a mic or an instrument into a mic preamp. Connect the preamp
into a track of a multitrack recorder. The preamp might be built into
a mixer.
2. Record the instrument or vocal on one track.
3. Repeat this process with another instrument on another track, and
so on—up to several tracks. Or record a group of instruments at once
on multiple tracks.
4. Mix all these tracks with a mixer, combining them to 2 tracks of
stereo music.
5. Record the stereo mix on a 2-track recorder. Repeat these steps for
several songs.
6. Edit the mixes to put a few seconds of silence between the songs,
and to put the songs in the desired order.
7. Copy the edited mixes onto a CD-R.
This process can be done in several ways; there are many equipment
options. For example, you could record with a mini studio, MiniDisc
recorder, hard-disk recorder, computer recording software, or a MIDI
sequencer. I’ll briefly explain what this equipment does.
Low-Cost Recording Equipment
A low-cost system includes microphones, powered monitor speakers, and
a recording device.
Microphone
This device converts the sound of your voice (or any instrument) into an
electrical signal that can be recorded. Microphone sound quality varies
widely, so be sure to get one or more good mics costing at least $100 each.
Condenser mics require phantom power, which is provided either by a
phantom power supply or by XLR mic inputs in some mixers. Some condenser mics work on batteries. You’ll also need a mic cable and at least
one mic stand and boom costing about $35. If you want to record classical music in stereo, you’ll need either a stereo mic, or a matched pair of
high-quality condenser or ribbon mics of the same model number, plus
a stereo mic-stand adapter.
42
Equipping Your Studio
4
Monitor System
Another important part of your studio is the monitor system—a pair of
quality headphones or loudspeakers. You can use powered speakers, or
use nonpowered speakers with a separate power amplifier. An essential
tool, the monitor system tells you what you’re doing to the recorded
sound. The sound you hear over the monitors is approximately what the
final listener will hear. Very good headphones are available for $100 and
up, and good speakers cost about $400 a pair and up.
Recording Device
Four types of low-cost recording devices to choose from are a 2-track
recorder, mini studio, 8-track recorder-mixer, and a computer with an
audio interface and recording software. We’ll look at each one.
2-Track Recorder
This device is suitable for on-location recording of classical music: an
orchestra, symphonic band, string quartet, pipe organ, or soloist. Sometimes it can be used to record folk music or jazz. Some types of 2-track
recorder are a hard-drive recorder, MiniDisc recorder, CD recorder,
memory recorder, DAT, or laptop computer with recording software. Cost
is $400 and up.
Mini Studio (4-Track Recorder/Mixer)
Also called a portable studio or pocket studio, this unit combines a 4track recorder with a mixer—all in one portable chassis (Figure 4.1). It
records in MP3 format to a memory card. A mini studio lets you record
several instruments and vocals, then mix them to stereo or send them to
your computer via USB. (A USB is a type of cable and ports for highspeed data transfer.) The sound quality is good enough to make demos,
or to use as a musical scratchpad for ideas, but it is not quite good enough
to release commercial albums. Costing about $300 and up, a mini studio
can be a good choice for beginning recordists. Some manufacturers are
Tascam, Boss, Digitech, Fostex, Korg, and Zoom (Samson).
Mini Studio features:
• Records on a memory card such as Compact Flash or SmartMedia.
• Sends the mix to your computer via a USB port for editing or CD
burning.
43
Practical Recording Techniques
Figure 4.1
Mini studio.
• Its internal MIDI sound module (synthesizer) plays back MIDI
sequences. Includes MIDI files or rhythm patterns to jam with.
• Built-in effects.
• Built-in mic (in some models).
• Autopunch in/out.
• Battery or AC-adapter powered.
• Virtual tracks let you record multiple takes of a single performance,
then select your favorite during mixdown.
• Guitar-amp modeling simulates various guitar amps; mic modeling
simulates mic models.
• 2 mic inputs; records up to 2 tracks at a time. Plays back 4 tracks at
once.
Digital Multitracker (8-Track Recorder-Mixer)
A step up from a mini studio, the digital multitracker combines a digital
8-track recorder with a mixer in a single chassis (Figure 4.2). It’s convenient and portable. Plus, it offers CD sound quality and more tracks than
the 4-track mini studios. The 8-track recording medium is a hard drive,
Zip drive, MiniDisc, or Flash memory card. Other names for this device
are stand-alone Digital Audio Workstation (DAW), portable digital
studio, or recorder-mixer. The price is $400 to $1200.
Some features to look for:
44
Equipping Your Studio
4
JOG WHEEL
LCD SCREEN
FADERS
Figure 4.2
CONTROLS
Digital multitracker.
• Type of analog inputs: balanced or unbalanced. XLR and 1/4-inch TRS
(Tip-Ring-Sleeve) are balanced. RCA or 1/4-inch TS (Tip-Sleeve) are
unbalanced. Balanced inputs allow longer cable runs without
picking up hum.
• Number of mic inputs: 2 to 8.
• Number of mixer channels: 8 and up.
• Number of simultaneous recording tracks: Two may be enough if
you’re recording only a track or two at a time, but a band may need
to record all 8 tracks at once.
• Number of virtual tracks (recordings of separate takes of the same
instrument): 8 and up.
• Automation (the mixer stores and resets your mixes).
• Phantom power for condenser mics.
• Number of effects processors (1 to 3).
• Midi Time Code (MTC) and Midi Machine Control (MMC), tempo
map, and tap tempo.
• Backlit LCD display (bigger is better) with a waveform display.
• Built-in CD burner.
• A/D/A conversion: 16-bit is CD quality; 20- or 24-bit is better.
• Data compression (no data compression is preferred for higher
sound quality).
Computer DAW
Another low-cost recording setup has three parts: a personal computer,
an audio interface, and a digital-audio recording software (Figure 4.3).
45
Practical Recording Techniques
MONITOR
HARD
DRIVE
PCI SLOT, USB PORT,
OR FIREWIRE PORT
COMPUTER
KEYBOARD
ALESIS
FIREPORT
I/O INTERFACE
(BREAKOUT BOX)
SOUND CARD
MOUSE
CONTROLLER WITH I/O
AUDIO INTERFACES (CHOOSE ONE)
Figure 4.3
Computer with a choice of audio interface and recording software.
MIDI/Digital-Audio software is the same, but also records MIDI
sequences (explained later). The audio interface (such as a sound card)
converts audio from your mic preamp or mixer into a signal that is
recorded on the computer’s hard disk as a magnetic pattern. Eight tracks
or more can be recorded. The interface costs as little as $80 for a good
sound card; pro-quality sound cards cost $200 or more. Low-cost recording software runs about $30 to $200. It’s possible to make commercialquality recordings with a computer recording system. Details are in
Chapter 13, Computer Recording.
You mix the tracks with a mouse by adjusting the “virtual” controls
that appear on your computer screen. Then you record the mix on your
computer’s hard drive.
Using a mouse can be fatiguing and can lead to repetitive stress syndrome. As an alternative to the mouse, you might buy a control surface
($400 and up). It looks like a mixer with faders, but it adjusts the virtual
controls you see on the computer screen. That way you can use your computer for recording, and control the software with knobs and faders
instead of a mouse.
After all your songs are mixed to two stereo tracks, you can use the
software to edit the recording: remove noises and count-offs between
songs, put the songs in order with a few seconds of silence between them,
46
Equipping Your Studio
4
and match their perceived loudness. Then you use a CD-R burner to copy
the edited program to a CD-R. There’s your final product—ready to
duplicate.
A computer studio costs about the same as a mini studio and is more
powerful. It’s a bargain. But because software requires computer skills,
it’s a little harder to learn and use than a hardware multitracker. Software
recordings are at least CD quality—better than the MP3 recordings you
get with a mini studio.
A computer studio can record MIDI (Musical Instrument Digital
Interface) tracks as well as audio tracks. Using a piano-style keyboard or
drum-machine pads, you play synthesized musical instruments—bass,
drums, piano, etc. (Figure 4.4). Part of the recording software, called a
MIDI sequencer, records the keystrokes that you play on the piano-style
keyboard. When you play back the sequencer recording, it plays synthesized instruments from a sound card, sound module, synthesizer, or software synth.
As an alternative, use a keyboard workstation. This is a keyboard
synth with a built-in sequencer and effects. The workstation lets you
SEQUENCER PROGRAM
MIDI
INTERFACE
COMPUTER
MIDI
IN
MIDI OUT
MIDI IN AND OUT
SYNTH OR KEYBOARD MIDI CONTROLLER
Figure 4.4
MIDI sequencer recording with a computer.
47
Practical Recording Techniques
create the entire musical backup on a stereo pair of channels, all in the
keyboard. Then you record the audio from the keyboard into a computer.
If you want to add a vocal, use MIDI/digital-audio software. Mix the
tracks and burn a CD-R.
We’ve looked at several types of bare-bones recording setups. All
can help you create quality demos. You can go much higher in price to
get more features and better sound. For example, if you want to record
an entire band playing all at once, with each instrument having its own
mic, you’ll need a system with more microphones, more tracks, and more
headphones.
As we’ve seen, putting together a home studio or project studio
doesn’t have to cost much. As technology develops, better equipment is
available at lower prices. That dream of owning your own studio is
within reach.
Higher-Cost Recording Equipment
So far we’ve talked about devices that record 2 to 8 tracks. The next step
up in price, quality, and flexibility are these:
• A hard-disk multitrack recorder, a separate mixer, and signal processors (Figure 4.5)
• A 16-, 24-, or 32-track recorder-mixer
• A high-end computer recording system
This equipment is good enough to record albums for commercial
release. Let’s look at the mixer first.
Figure 4.5
48
A studio using a separate multitrack recorder and mixer.
Equipping Your Studio
4
Mixer
A mixer (Figure 4.6) is an electronic device with an elaborate control
panel. The mixer is connected to your multitrack recorder. You plug mics
and electric instruments into the mixer, which amplifies their signals.
While recording, you use the mixer to send those signals to the desired
recorder tracks and to set recording levels. During mixdown, the mixer
combines (mixes) the tracks to stereo. It also lets you adjust the sound
quality of each track. The price is about $500 and up. A large, complex
mixer is called a mixing console or board. Mixing consoles are explained
in more detail in Chapter 11.
Hard-Disk Recorder (HD Recorder)
This device records up to 24 tracks on a built-in hard drive (Figure 4.7).
Multiple recorders can be linked to get more tracks. Some examples are
the Alesis ADAT HD24XR, Tascam MX-2424, Otari DR-100, iZ Technology RADAR, Fostex D-2424LV, and Mackie HDR 24/96.
Figure 4.6
A mixer.
49
Practical Recording Techniques
Figure 4.7
A multitrack hard-disk recorder.
Figure 4.8
An effects unit.
Processors
Signal processors (Figure 4.8) are electronic devices (or software programs) that add special sonic effects such as reverberation, echo, chorus,
and flanging. A compressor is a processor that acts like an automatic
volume control. It turns down the vocal (or an instrument) when it is too
loud—making it much easier to listen to.
HD Recorder-Mixer with 16 to 32 Tracks
As we said before, a multitrack HD recorder can be combined with a
mixer in a single chassis, forming an HD recorder-mixer (Figure 4.9). It’s
also called a stand-alone DAW, portable digital studio, or digital multitracker. Effects and a CD burner are built in. Easy to use and connect,
the recorder-mixer is a good tool for recording bands in the studio and
in concert. Features to look for were given earlier in the above section
Digital Multitracker (8-Track Recorder-Mixer). Some manufacturers are
TASCAM, Akai, Korg, Fostex, Roland, Boss, and Yamaha.
High-End Recording Software and Hardware
The top DAW systems include elaborate recording software, and sometimes control surfaces and computer cards with DSP (Digital Signal
Processing).
50
Equipping Your Studio
4
JOG WHEEL
LCD SCREEN
FADERS
Figure 4.9
CONTROLS
HD recorder-mixer.
Equipment Details
Now let’s look more closely at each component of the recording studio.
Recorder
Here are some features found in all types of multitrack recorder.
Overdubbing
The musician plays along while listening to tracks already recorded and
records a new part on an unused track. For example, suppose you’ve
already recorded bass and drums and you want to add a guitar track. The
performer listens to a headphone mix of the bass track, drum track, and
his or her guitar signal. The musician plays the guitar while the bass and
drum tracks play, and you record the guitar on an unused track.
Recording Two or More Tracks at Once
Recording several tracks simultaneously is useful for recording a live performance or an entire band at once. When you record in a studio, you often
can record one or two tracks at a time. But when you record a live performance, you need to record all the tracks at once. Not all recorder-mixers
let you do this.
Punch-In/Out
Use the punch-in and punch-out functions to fix mistakes. As the
recorded track is playing, punch into record mode just before the mistake,
play a new correct part that is recorded, and punch out of record mode
51
Practical Recording Techniques
when you’re finished. Most recorders accept a footswitch so you can
punch-in with your foot while playing your instrument.
Bouncing Tracks
When you bounce (or ping-pong) tracks, you mix two or three tracks
together and record the result on an unused track. Then you can erase
the original tracks, freeing them for recording more instruments. This
way you can record up to nine tracks with a 4-track machine. All recordermixers permit bouncing.
Pitch Control
Pitch control lets you adjust the recording speed up or down so you can
match the pitch of recorded tracks to the pitch of new instruments to be
recorded.
Locate
With this feature, certain locations in the recording can be stored in
memory, such as the beginning of a verse or chorus. When you press
“locate,” the recorder goes to that location. You could use this feature to
record repeatedly between two preset points, such as the beginning and
end of a punch-in. A similar feature is return-to-zero, also called locate to
zero, where the recorder goes to the beginning of the song. This feature
makes it easy to practice a mix repeatedly.
Mixer
Described below are some of the features in mixers.
Mic Inputs
How many mics and mic inputs do you need? It depends on the
instruments you want to record. If you want to mic a drum set, you
might need 8 mics and 8 mic inputs, mixing those to 1 or 2 tracks. On
the other hand, if you use MIDI instruments, you might need only one
good mic for vocals and acoustic instruments. You can use one mic on
several different instruments and vocals if you overdub them one at a
time.
Mic input connectors are XLR or a 1/4-inch phone jack. An XLR connector looks like three small holes arranged in a triangle. If your mixer
has such inputs, you can run long mic cables without picking up hum.
(Hum is an unwanted low-pitched tone at 50 or 60 Hz caused by power
52
Equipping Your Studio
4
wiring.) XLRs are found only in high-end units. Lower-cost recordermixers use 1/4-inch phone jacks (receptacles) for mic inputs, which are
adequate for small studios. But to use them, you may need some female
XLR-to-1/4-inch impedance-matching adapters. These are available at
Radio Shack.
Insert Jacks
Insert jack connectors let you plug in a compressor in line with an input
signal to reduce the dynamic range of that signal. A compressor is most
often used on lead vocals.
Equalization
Equalization (EQ) means tone control. The simplest units have no EQ;
you’re stuck with the sound you get from your microphones. Most inexpensive units include a bass and treble control, one set per input. Fancier
recorder-mixers have sweepable or semi-parametric EQ, which lets you
continuously vary the frequency you want to adjust. This type of EQ
offers the most control over the tone quality of each instrument you’re
recording.
Effects
A recording without effects sounds rather dead and plain. Effects such as
reverberation, echo, and chorus can add sonic excitement to a recording.
They are produced by devices called signal processors (see Figure 4.8) or
by plug-ins, which are software effects used in a computer recording
program.
The most essential effect is reverberation, a slow decay of sound
such as you hear just after you shout in an empty gymnasium (HELLOO-O-o-o-o . . .). Reverberation adds a sense of space; it can put your music
in a concert hall, a small club, or a cathedral. This effect is usually produced by a digital reverb unit, available for $200 and up, or as a software
plug-in.
Another popular effect is echo, a repetition of a sound (HELLO hello
hello). It’s made by a delay unit or delay plug-in, which also provides
other effects such as chorus, doubling, and flanging.
A multieffects processor combines several effects in a single box.
These effects can be heard one at a time or several at once. You can customize the sounds by pushing buttons to change the presets. (See Chapter
10 for more information on effects.)
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Practical Recording Techniques
Although effects are built into most recording software and recordermixers, an analog mixer needs to be used with external effects units. On
the mixer is a set of connectors (labeled send and return) for hooking up
an external effects unit, such as a reverb or delay device. A unit with one
effects send lets you add one type of effect; a unit with two effects sends
lets you add two different effects to create more sonic interest.
Microphones
Another essential item for the studio is a microphone. Good mics are
needed for quality sound—and you get what you pay for. If you experiment with various types of microphones, you find big differences in
fidelity. One or more microphones costing at least $100 each are recommended. It’s false economy to use a cheap mic. You can’t skimp here and
expect to get quality sound. Any distortion or weird tone quality in the
microphone may be difficult or impossible to remove later.
You may be able to borrow some good microphones, or use the ones
you normally use for PA. Your ears should tell you if the fidelity is
adequate for your purpose. Some people are happy to get any sound
recorded; others settle for nothing less than professional sound quality.
Probably the most useful mic types for home recording are the cardioid condenser mic and cardioid dynamic mic. The cardioid pickup
pattern helps reject room acoustics for a tighter sound. The condenser
type is commonly used on cymbals, acoustic instruments, and studio
vocals; dynamics are used typically on drums and guitar amps. (For more
information on microphones, see Chapter 6.)
If you plan to record solo instruments or musical ensembles in stereo
with two mics at a distance, you need two condenser mics of the same
model number, or a stereo microphone. See Chapter 18 for details.
Phantom-Power Supply
A phantom-power supply powers the circuits in condenser mics. It uses
the same cable that carries the mic’s audio signal. You can omit the supply
if your condenser mic has a battery, or if your mixer supplies phantom
power.
Mic Preamp
This device amplifies a mic signal up to a higher voltage, called line level,
which is needed by mixers and recorders. A stand-alone mic preamp pro-
54
Equipping Your Studio
4
vides a little cleaner sound than a mic preamp built into a mixer, but costs
much more. Studios on a budget can do without it.
Direct Box
A direct box is a useful accessory for recorder-mixers with balanced XLRtype mic inputs. A direct box is a small device that connects an electric
instrument (guitar, bass, synth) to a mixer’s XLR-type mic input. It lets
you record electric instruments directly into your mixer without a microphone. You can buy a direct box for as little as $50.
A direct box picks up a very clean sound, which may be undesirable
for electric guitar. If you want to pick up the distortion of the guitar amp,
use a microphone instead. Or use a guitar-amp modeling device or modeling plug-in.
Some recorder-mixers have “high-impedance” inputs meant for
electric guitars. In this case, simply use a short guitar cord between your
instrument and the mixer high-impedance input.
Monitor System
The monitor system lets you hear what you’re recording and mixing. You
can use a pair of high-quality headphones and a pair of loudspeakers and
a power amplifier. The power amplifier strengthens the mixer’s signal so
it can drive loudspeakers. An alternative is a pair of powered monitors
with built-in amplifiers.
The speakers should be accurate, high-fidelity types costing at least
$200 each. Your home stereo might be good enough to serve, but skimping on a monitor system is not a smart move.
Nearfield studio monitor speakers (described in Chapter 5) are
small, bookshelf-type speakers that are placed about 3 feet apart and 3
feet from you as you sit at your mixer.
If your monitor speakers are in the same room as your microphones,
the mics pick up the sound of the speakers. This causes feedback or a
muddy sound. In this case, it’s better to monitor with headphones while
recording.
If you’re recording only yourself, one set of headphones is enough.
But if you’re recording another musician, you both need headphones.
Many recorder-mixers have two headphone jacks for this purpose.
If you want to record or overdub several people at once, you need
headphones for all of them. For example, if you’re overdubbing three
55
Practical Recording Techniques
harmony vocalists, each one needs headphones to hear previously
recorded tracks to sing with. To connect all these headphones, you could
build a headphone junction box—an aluminum or plastic box that contains several headphone jacks. These are wired to a cable coming from
your mixer’s headphone jack. Or you could use a splitter cable, which
makes two jacks out of one.
Rack and Patch Bay
A rack is an enclosure in which signal processors and other equipment
are mounted. A patch bay or patch panel in a rack is a group of connectors that are wired to equipment inputs and outputs. Neither one is essential, but they are convenient. If you have a computer studio in which all
the processing is done by software plug-ins, you may not need a patch
bay.
Miscellaneous Equipment
Other equipment for your home studio includes mic cables, audio cables,
USB or FireWire cables, power outlet strips, lighting, tables or studio furniture, mic pop filters, masking tape and a pen to label inputs and cables,
contact cleaning fluid, DAT and MDM cleaning tapes, MIDI equipment
stands, music stands, session forms, connector adapters, pen and paper,
a flashlight, and so on.
Blank Recording Media
For your recorder you need some blank media to record on. Use the brand
suggested by the recorder manufacturer. Listed below are the media used
by various recorders:
Computer: Hard drive, CD-R, or CD-RW
HD recorder: A hard drive, which is built-in or removable
Digital multitracker (8-track recorder-mixer): A hard drive, MiniDisc data disc, or a Flash memory card
Mini studio (4-track recorder-mixer): Flash memory card
Modular digital multitrack: S-VHS cassette (Alesis) or Hi-8 video
cassette (Tascam).
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Equipping Your Studio
4
MIDI Studio Equipment
MIDI studio equipment is covered in detail in Chapter 16. Here are some
components in a typical MIDI studio that uses a piano-style synthesizer
and a drum machine to make sounds (Figure 4.10).
MIDI Controller
A MIDI controller is a musical-performance device, such as a piano-style
keyboard or drum pads, that puts out a MIDI signal when you play it. A
MIDI signal is a string of numbers that tells which notes you played,
when you played them, and so on.
Synthesizer
A synthesizer (synth) is a device or software that simulates the sound of
real musical instruments or generates original sounds. There are several
types. A stand-alone or hardware synthesizer has a piano-style keyboard
and sound generators. When you play this instrument, it produces both
a MIDI and an audio signal. Other types of synthesizers are a synth chip
on a sound card, a stand-alone sound module, or a software synth.
SEQUENCER PROGRAM
MIDI
INTERFACE
COMPUTER
MIDI
IN
LINE
MIXER
MIDI OUT
AUDIO
MIDI IN
MIDI
OUT
MIDI
IN
MIDI THRU
OUT
IN
DRUM MACHINE
OUT TO POWERED
SPEAKERS
AUDIO
OUT
IN
MIDI CONTROLLER / SYNTHESIZER
Figure 4.10
One type of MIDI studio.
57
Practical Recording Techniques
Sequencer
A sequencer is a device, or a computer program, that records the MIDI
signal of your performance into computer memory for later editing and
playback. It also records notes that you enter on a musical scale. The notes
can be edited. A sequence is a computer .mid file of the notes you played,
their timing, their volume, etc.
Sampler
A sampler is a device or a software plug-in that records and plays single
notes, or short musical phrases, of real musical instruments. The sampler
stores the samples in computer memory or on CD-Rs and floppy disks.
To play the recorded samples, you trigger them with a MIDI controller
or sequencer.
Sound Module
A sound module is a device that plays prerecorded samples or synthesized sounds when triggered by a MIDI controller or sequencer. It does
not record samples.
Drum Machine
A drum machine is a device that simulates a drummer. It’s a sequencer
that records a drum performance done on its built-in pads. Each pad
plays a different drum sound. When you play back your recorded performance, the samples play. This simulates a drum set and percussion.
Many recorder-mixers have a drum machine built in.
Line Mixer
A line mixer is a small mixer that combines the signals of synths, sound
modules, samplers, and drum machines. A line mixer has no mic
preamps. If you want to use a mic with your MIDI studio, you also need
a mic preamp or a mixer with mic preamps. If all your synthesizers are
inside your computer, you don’t need a line mixer.
MIDI Interface
A MIDI interface is a circuit card or device that connects to a computer,
and has a MIDI IN connector and MIDI OUT connector. It converts a
MIDI signal into computer data, and vice versa, so that you can record,
edit, and play back a performance done on a MIDI controller. There are
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Equipping Your Studio
4
four types of MIDI interface: a MIDI card, a sound card with MIDI connectors, an I/O interface, and a control surface.
MIDI Software
Listed below are some types of MIDI software.
• Sequencer software ($30 to $1500): Records a performance done on
a MIDI controller, or records notes that you enter on a musical scale.
The notes can be edited.
• MIDI/digital-audio software ($30 to $1500): Also called digitalaudio sequencer software. This software lets you record MIDI
sequences (from a MIDI controller) and digital audio tracks (from
mics) on a hard disk. The sequences and digital audio play at the
same time in sync. Both can be edited.
• Notation software ($80 to $600): Displays your performance as a
score on screen. You can edit the notes, type in lyrics and chords,
and print out the score. Some recording software has notation
included.
• Editor/librarian software ($200): Edits synth patches and stores
them on disk.
Setting Up Your Studio
Once you have your equipment, you need to connect it together with
cables, and possibly install equipment racks and acoustic treatment. Let’s
consider each step.
Cables
Cables carry electric signals from one audio component to another. They
are usually made of one or two insulated conductors (wires) surrounded
by a fine-wire mesh shield that reduces hum. Outside the shield is a
plastic or rubber insulating jacket. On both ends of each cable is a connector (which comes in various types).
Cables are either balanced or unbalanced. A balanced line is a cable
that uses two wires (conductors) to carry the signal surrounded by a
shield (see Figure 4.11). Each wire has equal impedance to ground. An
unbalanced line has a single conductor surrounded by a shield (see
Figure 4.12). The balanced line rejects hum better than an unbalanced line,
59
Practical Recording Techniques
CABLE JACKET
INSULATION
HOT CONDUCTOR
COLD CONDUCTOR
SHIELD
Figure 4.11
A 2-conductor shielded, balanced line.
CABLE JACKET
CONDUCTOR
SHIELD
Figure 4.12
A 1-conductor shielded, unbalanced line.
but an unbalanced line less than 10 feet long usually provides adequate
hum rejection and costs less.
A cable carries one of these four signal levels or voltages:
• Mic level (about 2 millivolts, or 0.002 volt)
• Electric guitar or keyboard level (about 0.1 volt)
• Line level (0.316 volt for unbalanced equipment, 1.23 volts for
balanced equipment)
• Speaker level (about 20 volts)
The term “0.316 volt” also is known as “-10 dBV”; the term “1.23
volts” also is known as +4 dBu (see Appendix A).
Equipment Connectors
Recording equipment also has balanced or unbalanced connectors built
into the chassis. Be sure your cable connectors match your equipment
connectors.
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Equipping Your Studio
4
Balanced equipment connectors include:
• 3-pin (XLR-type) connector (Figure 4.13)
• 1/4-inch TRS phone jack (Figure 4.14)
Unbalanced equipment connectors:
• 1/4-inch TS (Tip-Sleeve) phone jack (Figure 4.14)
• Phono jack (RCA connector) (Figure 4.15)
A jack is a receptacle; a plug inserts into a jack.
Cable Connectors
There are several types of cable connectors used in audio. Figure 4.16
shows a 1/4-inch mono phone plug (or TS phone plug) used with cables
for unbalanced microphones, synthesizers, and electric instruments. The
Figure 4.13
Figure 4.14
equipment.
Figure 4.15
A 3-pin XLR-type connector used in balanced equipment.
A 1/4-inch phone jack used in balanced and unbalanced
A phono (RCA) jack used in unbalanced equipment.
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Practical Recording Techniques
Figure 4.16
A mono (TS) 1/4-inch phone plug.
Figure 4.17
An RCA (phono) plug.
tip terminal is soldered to the cable’s center conductor; the sleeve terminal is soldered to the cable shield.
Figure 4.17 shows an RCA or phono plug, used to connect unbalanced line-level signals. The center pin is soldered to the cable’s center
conductor; the cup terminal is soldered to the cable shield.
Figure 4.18 shows a 3-pin pro audio connector (XLR type). It is used
with cables for balanced mics and balanced recording equipment. The
female connector (with holes; Figure 4.18A) plugs into equipment
outputs. The male connector (with pins; Figure 4.18B) plugs into equipment inputs. Pin 1 is soldered to the cable shield, pin 2 is soldered to the
“hot” red or white lead, and pin 3 is soldered to the remaining lead. This
wiring applies to both female and male connectors.
Figure 4.19 shows a stereo (TRS) phone plug used with stereo headphones and with some balanced line-level cables. For headphones, the
tip terminal is soldered to the left-channel lead; the ring terminal is
soldered to the right-channel lead; and the sleeve terminal is soldered to
the common lead. For balanced line-level cables, the sleeve terminal
is soldered to the shield; the tip terminal is soldered to the hot red or
white lead; and the ring terminal is soldered to the remaining lead.
Some mixers have insert jacks that are stereo phone jacks; each jack
accepts a stereo phone plug. Tip is the send signal to an audio device
input, ring is the return signal from the device output, and sleeve is
ground.
62
4
Equipping Your Studio
Figure 4.18
A 3-pin pro audio connector (XLR-type). (A) female. (B) male.
Figure 4.19
A stereo (TRS) phone plug.
If you have unbalanced microphone inputs (1/4-inch diameter
holes) on your recorder or mixer, use a balanced cable (with XLRs on both
ends) from mic to input. This reduces hum. At the mixer input, plug an
impedance-matching adapter into the mic cable and into the mixer input.
Sold at Radio Shack, the adapter has a female XLR connector on one end
and a 1/4-inch phone plug on the other (see Figure 4.20).
Cable Types
Cables are also classified according to their function. In a studio, you’ll
use several types of cables: power, mic, MIDI, speaker, USB, FireWire,
S/PDIF, Tascam TDIF, and Alesis Lightpipe cables. You’ll also use guitar
cords and patch cords, which are also cables.
A power cable (an AC extension cord or a power cord on a device)
is made of three heavy-gauge wires surrounded by an insulating jacket.
The wires are thick to handle lots of current.
A mic cable is usually 2-conductor shielded. It has two wires to carry
the signal, surrounded by a fine-wire cylinder or shield that reduces hum
63
Practical Recording Techniques
Figure 4.20
An impedance-matching adapter.
STAGE BOX
CONNECTORS TO
MIC CABLES
SNAKE
CONNECTORS TO MIXER
Figure 4.21
A stage box and snake.
pickup. On one end of the cable is a connector that plugs into the microphone, usually a female XLR-type. On the other end is either a 1/4-inch
phone plug or a male XLR-type connector that plugs into your mixer.
Rather than running several mic cables to your recorder-mixer, you
might consider using a snake—a box with multiple mic connectors—all
wired to a thick multiconductor cable (Figure 4.21). A snake is especially
convenient if you’re running long cables to recording equipment. It’s
essential for most on-location recording.
Professional balanced equipment is interconnected with mic cable:
2-conductor shielded cable having a female XLR on one end and a male
XLR on the other. Professional patch bays use balanced cables with TRS
phone plugs.
64
Equipping Your Studio
4
A MIDI cable uses a 5-pin DIN connector on each end of a 2conductor shielded cable. The cable connects MIDI OUT to MIDI IN or
MIDI THRU to MIDI IN.
A speaker cable connects the power amp to each loudspeaker.
Speaker cables are normally made of lamp cord (zip cord). To avoid
wasting power, speaker cables should be as short as possible and should
be heavy gauge (between 12- and 16-gauge). Number 12 gauge is thicker
than 14; 14 is thicker than 16.
A USB cable or a FireWire cable connects a peripheral device (like
an audio interface) to a computer. USB and FireWire are covered in detail
in Chapter 13.
An S/PDIF cable transfers a digital signal from one device’s S/PDIF
output to another device’s S/PDIF input. It uses a shielded unbalanced
cable (ideally a 75-ohm RG59 video cable) with an RCA plug on each end.
A Tascam TDIF cable is a multiconductor cable with a 25-pin D-sub
connector on both ends. It’s used to connect multiple digital-audio signals
from Tascam multitrack recorders to digital mixers or computer TDIF
interfaces.
An Alesis Lightpipe cable is an optical cable with a Toslink connector on both ends. This cable is used to connect 8 channels of digital-audio
signals from an Alesis multitrack recorder to a digital mixer or computer
Lightpipe interface.
A guitar cord is made of 1-conductor shielded cable with a 1/4-inch
phone plug on each end. It connects between a direct box and an electric
musical instrument: guitar, bass, synthesizer, or drum machine.
Patch cords connect your recorder-mixer to external devices: an
effects unit, a 2-track recorder, and a power amplifier. They also connect
an analog mixer to the analog inputs and outputs of a multitrack recorder,
usually as a snake that combines several cables. An unbalanced patch
cord is made of 1-conductor shielded cable with either a 1/4-inch phone
plug or a phono (RCA) connector on each end. A stereo patch cord is two
patch cords joined side by side.
Rack/Patch Bay
You might want to mount your signal processors in a rack—a wooden or
metal enclosure with mounting holes for equipment (Figure 4.22). You
also might want to install a patch panel or patch bay: a group of connectors that are wired to equipment inputs and outputs. Using a patch
bay and patch cords, you can change equipment connections easily. You
65
Practical Recording Techniques
Figure 4.22
A rack and patch panel.
also can bypass or patch around defective equipment. Note that patch
bays increase the chance of hum pickup slightly because of the additional
cables and connectors.
Figure 4.23 shows some typical patch-panel assignments.
Equipment Connections
The instruction manuals of your equipment tell how to connect each component to the others. In general, use cables that are as short as possible
to reduce hum, but that are long enough to let you make changes.
Be sure to label all your cables on both ends according to what they
plug into; for example, TRACK 6 OUT or REVERB IN. If you label your
cables, when you change connections temporarily, or the cable becomes
unplugged, you’ll know where to plug it back in. A piece of masking tape
folded over the end of the cable makes a stay-put label.
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Equipping Your Studio
Figure 4.23
4
Some typical patch-bay assignments.
POWER AMPLIFIER
AND MONITOR SPEAKERS,
OR POWERED MONITORS
MICS / DI
MICS
IN
SNAKE
MONITOR
OUT
L
R
MIXER
HEADPHONES
L
R
INSERT
SEND/RETURNS
IN / OUT
TAPE/LINE
LINE
OUT
IN
LINE
OUT
TAPE/LINE
IN
COMPUTER
WITH AUDIO
INTERFACE
MULTITRACK
RECORDER
(OPTIONAL)
Figure 4.24
Typical connections for recording-studio equipment.
Typically, you follow this procedure to connect equipment (see
Figure 4.24):
1. Plug the AC power cords of audio equipment and electric musical
instruments into AC outlet strips fed from the same circuit breaker.
Plug the power amplifier into its own outlet on the same breaker so
that it receives plenty of current.
2. Connect mics and direct boxes to mic cables.
3. Connect mic cables either to the snake junction box or directly into
mixer mic inputs. Connect the snake connectors into mixer mic
67
Practical Recording Techniques
4.
5.
6.
7.
8.
9.
10.
inputs. If your mixer has phone-jack mic inputs, you may need to
use an impedance-matching adapter (female XLR to phone) between
the mic cable and the mic input jack (Figure 4.20).
Set the output volume of synthesizers and drum machines about
three-quarters up. Connect the synthesizer’s and drum machine’s
audio outputs to mixer line inputs. If this causes hum, use a direct
box.
If the mixer is a stand-alone unit (not part of a recorder-mixer),
connect the mixer 2-track or tape outputs to the inputs of a 2-track
recorder (DAT, computer audio interface, or MiniDisc recorder).
Connect the 2-track recorder outputs to the mixer’s 2-track or tape
inputs.
Connect the mixer’s monitor outputs to the power-amp inputs.
Connect the power-amp outputs to loudspeakers. Or if you are using
powered (active) monitors, connect the mixer monitor outputs to the
monitor-speaker inputs.
If the mixer does not have internal effects, connect the mixer auxsend connectors to effects inputs (not shown). Connect the effects
outputs to the mixer aux-return or bus-in connectors.
If you’re using a separate mixer and multitrack recorder, connect
mixer bus 1 to recorder track 1 IN; connect bus 2 to track 2, and
so on. Also connect the recorder’s track 1 OUT to the mixer’s line
input 1; connect the track 2 OUT to the mixer’s line input 2, and so
on. As an alternative, connect insert jacks to multitrack inputs and
outputs. At each insert plug, connect the tip (send) terminal to a
track input and connect the ring (return) terminal to the same track’s
output.
If you have several headphones for musicians, connect the cue
output to a small amplifier to drive their headphones. Or if the
mixer’s headphone signal is powerful enough, connect it to a box
with several headphone jacks wired in parallel.
Semi-pro studio equipment with unbalanced connectors (usually
phone or RCA) operates at a level called -10 or -10 dBV. Pro studio equipment with balanced connectors (XLR or TRS) works at +4 or +4 dBu.
Check your equipment manuals to determine their input and output
levels. When you connect devices that run at different levels, set the +4/
-10 switch on each unit to match the levels. If there is no such switch
on either device, connect between them a +4/-10 converter box such as
68
Equipping Your Studio
4
the Ebtech Line Level Shifter (www.ebtechaudio.com). Or try the cables
shown in Appendix A, Figures A.3 and A.4.
Figure 4.25 shows a typical layout for a DAW recording studio that
uses the same equipment just described.
A recorder-mixer studio can be quite simple. It omits the external
multitrack recorder, computer, computer monitor and keyboard, audio
interface, and outboard effects.
Acoustic Treatment
Along with the recording equipment, you need a quiet room to record
in—the larger the better. A basement, living room, or bedroom can work.
Many garages have been turned into studios.
If the room has a lot of hard surfaces, you might need to place some
material in the studio to absorb sound reflections. This treatment reduces
the reverberation in the room and gives a clearer recorded sound. For
budget or improvised studios, the acoustic treatment has to be limited.
Try surrounding the instrument and its mic with thick blankets or sleeping bags hung a few feet away. Maybe hang them on ropes tied between
room fixtures. Carpet the floor and nail some convoluted (bumpy) mattress foam to wood-paneled walls (make sure it is fire-proofed). Put
muslin-covered 2-ft ¥ 4-ft pieces of 705 fiberglass insulation across each
COMPUTER
MONITOR
LEFT
SPEAKER
HEADPHONES
TO MIXER
MIC INPUTS
SNAKE
MICS
Figure 4.25
RIGHT
SPEAKER
MIXER
COMPUTER
KEYBOARD
COMPUTER
WITH AUDIO
INTERFACE
MULTITRACK
RECORDER
(OPTIONAL)
Typical layout of a DAW recording studio.
69
Practical Recording Techniques
corner to absorb bass. You might prefer to use some commercially made
sound absorbers.
Add absorbers spaced evenly around the walls until your recordings sound reasonably dry (free of audible room reverberation). There’s
more on acoustic treatments in Chapter 3.
Note: By using close miking, direct boxes, and overdubs, you might
be able to make good recordings in a room without any acoustic
treatment.
Hum Prevention
You patch in a piece of audio equipment, and there it is—HUM! It’s a
low-pitched tone or buzz. This annoying sound is a tone at 60 Hz (50 Hz
in Europe) and multiples of that frequency.
Hum is caused mainly by
• Cables picking up magnetic and electrostatic hum fields radiated by
power wiring—especially if the cable shield connection is broken.
• Ground loops. A ground loop is a circuit made of ground wires. It
can occur when two pieces of equipment are connected to ground
through a power cord, and also are connected to each other through
a cable shield. The ground voltage may be slightly different at each
piece of equipment, so a 50- or 60-Hz hum signal flows between the
components along the cable shield.
These are the most important points to remember about hum
prevention:
• To prevent ground loops, plug all equipment into outlet strips
powered by the same breaker.
• Some power amps create hum if they don’t get enough AC current.
So connect the power amp (or powered speakers) AC plug to its own
wall outlet socket—the same outlet that feeds the outlet strips for
the recording equipment.
• If possible, use balanced cables going into balanced equipment.
Balanced cables have XLR or TRS connectors and two conductors
surrounded by a shield. Ideally, the shield should be connected to
the chassis ground (not the signal ground) at both ends of the cable.
• Transformer-isolate unbalanced connections. If that is not an option,
use the cable assemblies shown in Figures 3 and 4 in Appendix A.
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Equipping Your Studio
4
• Don’t use dimmers to change the studio lighting levels. Use multiway incandescent bulbs instead.
Even if your system is wired properly, a hum or buzz may appear
when you make a connection. Follow these tips to stop the hum:
• If the hum is coming from a direct box, flip its ground-lift switch.
• Check cables and connectors for broken leads and shields.
• Unplug all equipment from each other. Start by listening just to the
powered monitor speakers. Connect a component to the system one
at a time, and see when the hum starts.
• Remove audio cables from your devices and monitor each device by
itself. It may be defective.
• Turn down the volume on your power amp (or powered speakers),
and feed them a higher-level signal.
• Use a direct box instead of a guitar cord between instrument and
mixer.
• To stop a ground loop when connecting two devices, connect
between them a 1 : 1 isolation transformer or hum eliminator (such
as Jensen or Ebtech). See Figures 3 and 4 in Appendix A.
• Add ground-lift adapters to line-level balanced cables at the male
XLR end. Caution: a lifted (disconnected or “telescoping”) shield
can act as an RF antenna. To prevent RFI pickup, solder a 0.001microfarad (mF) capacitor between the lifted shield and XLR pin 1.
• Make sure that the snake box is not touching metal.
• Do not connect XLR pin 1 to the connector shell. Tighten the
mic-connector screws.
• Try another mic.
• If you hear a hum or buzz from an electric guitar, have the player
move to a different location or aim in a different direction. You might
also attach a wire between the player’s body and the guitar strings
near the tailpiece to ground the player’s body.
• Turn down the high-frequency EQ on a buzzing bass guitar track.
• To reduce buzzing between notes on an electric-guitar track, apply
a noise gate.
• Route mic cables and patch cords away from power cords; separate
them vertically where they cross. Also keep recording equipment
71
Practical Recording Techniques
and cables away from computer monitors, power amplifiers, and
power transformers.
• See Rane’s excellent article on sound system interconnections at
www.rane.com.
By following all these tips, you should be able to connect audio
equipment without introducing any hum. Good luck!
Reducing Radio Frequency Interference
Radio frequency interference (RFI) is heard as buzzing, clicks, radio
programs, or “hash” in the audio signal. It’s caused by CB transmitters,
computers, lightning, radar, radio and TV transmitters, industrial
machines, auto ignitions, stage lighting, and other sources. Many of the
following techniques are the same used to reduce hum from other
sources. To reduce RFI:
• If you think that a speaker cable, mic cable, or patch cord is picking
up RFI, wrap the cable several times around an RFI choke (available
at Radio Shack). Put the choke near the device that is receiving
audio.
• Install high-quality RFI filters in the AC power outlets. The cheap
types available from local electronics shops are generally ineffective.
• If a cable shield is floating (disconnected) at one end, solder a 0.001mF capacitor between XLR pin 1 and the shield.
• If a MIC is picking up RFI, solder a 0.047 mF capacitor between pin
1 and 2, and between pin 1 and 3, in the female XLR connector of
the MIC cable.
• Periodically clean connector contacts with Caig Labs De-Oxit, or at
least unplug and plug them in several times.
This chapter briefly covered the equipment and connectors for a
recording studio. The rest of this book explains each piece of equipment
in detail and tells how to use it for best results.
72
5
MONITORING
One of the most exciting moments in recording comes when the finished
mix is played over the studio monitor speakers. The sound is so clear
you can hear every detail, and so powerful you can feel the deep bass
throbbing in your chest.
You use the monitor system to listen to the output signals of the
console or the recorders. It consists of the console monitor mixer, the
power amplifiers, loudspeakers, and the listening room. The power
amplifier boosts the electrical power of the console signal to a sufficient
level to drive a loudspeaker. The speaker converts the electrical signal
into sound, and the listening-room acoustics affect the sound from the
speaker.
A quality monitor system is a must if you want your mixes to sound
good. The power amp and speakers tell you what you’re doing to the
recorded sound. According to what you hear, you adjust the mix and
judge your mic techniques. Clearly, the monitor system affects the settings of many controls on your mixer, as well as your mic selection and
placement. And all those settings affect the sound you’re recording. So,
using inadequate monitors can result in a poor-sounding product coming
out of your studio.
It’s important to use accurate speakers that have a flat frequency
response. If your monitors are weak in the bass, you will tend to boost
the bass in the mix until it sounds right over those monitors. But when
that mix is played over speakers with a flatter response, it will sound too
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Practical Recording Techniques
bassy because you boosted the bass on your mixer. So, using monitors
with weak bass results in bassy recordings; using monitors with exaggerated treble results in dull recordings, and so on. In general, colorations
in the monitors will be inverted in your mixdown recording.
That’s why it’s so important to use an accurate monitor system—
one with a wide, smooth frequency response. Such a system lets you hear
exactly what you recorded.
Speaker Requirements
The requirements for an accurate studio monitor are these:
• Wide, smooth frequency response. To ensure accurate tonal reproduction, the on-axis response of the direct sound should be ±4 dB or
less from 40 Hz to 15 kHz. The low-frequency response of a small
monitor speaker should extend to at least 70 Hz.
• Uniform off-axis response. The high-frequency output of a speaker
tends to diminish off-axis. Ideally the response at 30 degrees off-axis
should be only a few decibels down from the response on-axis. That
way, a producer and engineer sitting side-by-side will hear the same
tonal balance. Also, the tonal balance will not change as the engineer moves around at the console.
• Good transient response. This is the ability of the speaker to accurately follow the attack and decay of musical sounds. If a speaker
has good transient response, the bass guitar sounds tight, not boomy
and drum hits have sharp impact. Some speakers are designed so
that the woofer and tweeter signals are aligned in time. This aids
transient response.
• Clarity and detail. You should be able to hear small differences in
the sonic character of instruments, and to sort them out in a complex
musical passage.
• Low distortion. Low distortion is necessary because it lets you listen
to the speaker for a long time without your ears hurting. A good
spec might be: Total harmonic distortion under 3% from 40 Hz to
20 kHz at 90 dBSPL (sound pressure level).
• Sensitivity. Sensitivity is the sound pressure level a speaker produces at 1 meter (m) when driven with 1 watt (W) of pink noise.
Pink noise is random noise with equal energy per octave. This noise
is either band-limited to the range of the speaker or is a one-third-
74
Monitoring
5
octave band centered at 1 kHz. Sensitivity is measured in dB/W/m
(dB sound pressure level per 1 W at 1 m). A spec of 93 dB/W/m is
considered high; 85 dB/W/m is low. The higher the sensitivity, the
less amplifier power you need to get adequate loudness.
• High output capability. This is the ability of a speaker to play loudly
without burning out. You often need to monitor at high levels to hear
quiet details in the music. Plus, when you record musicians who
play loudly in the studio, it can be a letdown for them to hear a quiet
playback. So you may need a maximum output of 110 dBSPL.
This formula calculates the maximum output of a speaker (how loud it
can play):
dBSPL = 10 log (P) + S
where dBSPL is the sound pressure level at 1 m, P is the continuous power
rating of the speaker in watts, and S is the sensitivity rating in dB/W/m.
For example, if a speaker is rated at 100 W maximum continuous
power, and its sensitivity is 94 dBSPL/W/m, its maximum output SPL is
10 log(100) + 94 = 114 dBSPL (at 1 m from the speaker). The level at 2 m
will be about 4 to 6 dB less.
NearfieldTM Monitors
Many professional recording studios use large monitor speakers that
have deep bass. However, they are expensive, heavy, and difficult to
install, and they are affected by the acoustics of the control room. If you
want to avoid this hassle and expense, consider using a pair of Nearfield
monitor speakers (Figure 5.1). A Nearfield monitor is a small, wide-range
speaker typically using a cone woofer and dome-shaped tweeter. You
place a pair of them about 3 or 4 feet apart, on stands just behind the
console, about 3 or 4 feet from you. Nearfields are far more popular than
large wall-mounted speakers.
This technique, developed by audio consultant Ed Long, is called
Nearfield monitoring. Because the speakers are close to your ears,
you hear mainly the direct sound of the speakers and tend to ignore
the room acoustics. Plus, Nearfield monitors sound very clear and
provide sharp stereo imaging. Some units have bass or treble tone controls built in to compensate for the effects of speaker placement and room
surfaces.
75
Practical Recording Techniques
Figure 5.1
A Nearfield monitor speaker.
Nearfield monitors have enough bass to sound full when placed far
from walls. Although most Nearfields lack deep bass, they can be supplemented with a subwoofer to reproduce the complete audio spectrum.
Or you can check the mix occasionally with headphones that have deep
bass.
Some Nearfields are in a satellite-subwoofer format. The two satellite speakers are small units, typically including a 4-inch woofer and
3/4-inch dome tweeter. The satellites are too small to produce deep bass,
but that is handled by the subwoofer—a single cabinet with one or two
large woofer cones. Typically, the subwoofer (sub) produces frequencies
from 100 Hz down to 40 Hz or below. Because we do not localize sounds
below about 100 Hz, all the sound seems to come from the satellite speakers. The sub-satellite system is more complicated to set up than two larger
speakers, but offers deeper bass.
76
Monitoring
5
Powered (Active) Monitors
Some monitors have a power amplifier built in. You feed them a line-level
signal (labeled MONITOR OUT) from your mixing console. Most
powered monitors are bi-amplified: they have one amplifier for the
woofer and another for the tweeter. The advantages of bi-amplification
include:
• Distortion frequencies caused by clipping the woofer power amplifier will not reach the tweeter, so there is less likelihood of tweeter
burnout if the amplifier clips. In addition, clipping distortion in the
woofer amplifier is made less audible.
• Intermodulation distortion is reduced.
• Peak power output is greater than that of a single amplifier of equivalent power.
• Direct coupling of amplifiers to speakers improves transient
response—especially at low frequencies.
• Bi-amping reduces the inductive and capacitive loading of the
power amplifier.
• The full power of the tweeter amp is available regardless of the
power required by the woofer amp.
The Power Amplifier
If your monitor speakers are not powered, you need a power amplifier
(Figure 5.2). It boosts your mixer’s line-level signal to a higher power in
order to drive the speakers.
How many watts of power do you need? The monitor speaker’s data
sheet gives this information. Look for the specification called “Recommended amplifier power.” A power amp of 50 W per channel continuous
is about the minimum for Nearfield monitors; 150 W is better. Too much
power is better than too little, because an underpowered system is likely
to clip or distort. This creates high frequencies that can damage tweeters.
A good monitor power amp has distortion under 0.05% at full
power. It should have a high damping factor—at least 100—to keep the
bass tight. The amp should be reliable. Look for separate level controls
for left and right channels. The amplifier should have a clip or peak light
that flashes when the amp is distorting.
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Practical Recording Techniques
Figure 5.2
A power amplifier.
Speaker Cables and Polarity
When you connect the power amp to the speakers, use good wiring
practice. Long or thin cables waste amplifier power by heating. So put
the power amp(s) close to the speakers and use short cables with thick
conductors—at least 16 gauge. The low resistance of these cables helps
the power amplifier to damp the speaker motion and tighten the bass.
If you wire the two speakers in opposite polarity, one speaker’s cone
moves out while the other speaker’s cone moves in. This causes vague
stereo imaging, weak bass, and a strange sense of pressure on your ears.
Be sure to wire the speakers in the same polarity as follows: In both channels, connect the amplifier positive (+ or red) terminal to the speaker
positive (+ or red) terminal. Setting the correct polarity is also called
“speaker phasing.”
Control-Room Acoustics
The acoustics of the control room affect the sound of the speakers. Sound
waves leaving each speaker strike the room surfaces. At those surfaces,
some frequencies are absorbed, while other frequencies are reflected. At
your ears, the sound waves reflected from the room surfaces combine
with the direct sound from the speakers. Reflections that arrive within 20
to 65 milliseconds (msec) after the direct sound blend with the direct
sound and affect the tonal balance you hear.
Suppose the walls are covered with carpet or blankets so that they
absorb only the high frequencies. Then the walls will reflect mainly the
low frequencies. When you listen to a speaker playing in such a room,
78
Monitoring
5
you hear the direct sound from the speaker plus the bassy wall reflections. The combined sound will be bass-heavy. Now suppose the walls
are made of wood paneling mounted on studs. Such a vibrating surface
absorbs lows and reflects highs. The sound you hear probably will be thin
and overly bright.
Clearly, the room surfaces should reflect (or absorb) all frequencies
about equally to avoid coloring the sound of the speakers. Equal absorption (±25%) from about 250 to 4000 Hz is usually adequate. As described
in Chapter 3, you can use flexible panels or bass traps to absorb lows, in
combination with fibrous materials or foam to absorb highs, or use thick
fibrous material spaced from the wall and ceiling.
Room resonances or standing waves can cause some bass notes to
blare out and cause other notes to disappear. Be sure to control these
resonances as suggested in Chapter 3.
Room acoustics also affect the decay-in-time of the sound coming
from the speakers. Whenever the speakers play a note that ends suddenly,
the sound of that note continues to bounce around the room. This causes
echoes and reverberation that prolong the sound. This long decay of
sound is not part of the recording. So the control room should be relatively dead; that is, it should have a short reverberation time. A typical
living room has a reverb time of about 0.4 seconds; the control room
should, too, so the engineer will hear about the same amount of room
reverb that a home listener will hear. A totally dead room is uncomfortable to listen in.
Using Nearfield monitors makes the room acoustics less important,
but it still helps to treat the room acoustics. To prevent sound reflections
from the wall behind the speakers, apply muslin-covered fiberglass insulation or acoustic foam. This treatment improves the monitors’ sound.
Stereo imaging and depth are greatly improved, the sound is clearer, and
the frequency response is flatter. The treatment will reduce boominess
and ringing, and make transients sharper. Also, your recordings will
translate better to other speakers.
If your control room is separate from the studio, the control room
should be built to keep out sound from the studio. You want to hear only
the sound from the monitors, not the live sound from the musicians. In
a home studio, you can achieve isolation simply by putting the controlroom equipment in a room far removed from the studio, with the doors
closed.
A control room built next to the studio needs good isolation. Use
double-wall construction with staggered studs (see Figure 5.3). Put
79
Practical Recording Techniques
Figure 5.3
Staggered-stud construction to reduce noise transmission.
fiberglass insulation between the two walls. The door between the two
rooms should be solid wood and should be weatherstripped all around—
including underneath. Use a double-pane window (mounted in rubber)
between the control room and studio.
In some home or project studios, the control room is the same room
as the studio. Because no isolation is used, the cost of building the studio
is much less. The engineer records while listening with headphones, and
does the critical monitoring during playback and mixdown.
Speaker Placement
Once you have acquired the speakers and worked on the room acoustics,
you can install the speakers. Mount them at ear height so the mixer
doesn’t block their sound. To prevent sound reflections off the mixing
console, place the speakers on stands behind the console’s meter bridge,
rather than putting them on top. For best stereo imaging, align
the speaker drivers vertically and mount the speakers symmetrically
with respect to the side walls. Place the two speakers as far apart as
you’re sitting from them; aim them toward you, and sit exactly between
them (Figure 5.4). To get the smoothest low-frequency response, put the
speakers near the shorter wall, and sit forward of the halfway point in
the room.
Try to position the monitors several feet from the nearest wall. Wall
reflections can degrade the frequency response and stereo imaging. The
closer to the wall the monitors are, the more bass you hear. In small rooms
you might have to place the monitors against the wall, which will exaggerate the bass. But some monitors have a low-frequency attenuation
switch to compensate.
80
Monitoring
SPKR
5
SPKR
D
D
D
LISTENER
Figure 5.4
imaging.
The recommended speaker/listener relationship for best stereo
Using the Monitors
You’ve treated the room acoustics, and you’ve connected and placed the
speakers as described earlier. Now it’s time to adjust the stereo balance.
1. Play a mono musical signal into an input channel on your mixer, and
assign it to the stereo output channels 1 and 2.
2. Adjust the input channel pan pot so that the signal reads the same
on the stereo output channel 1 and 2 meters.
3. Place the two speakers the same distance from you.
4. Sit at the mixer exactly midway between the speakers. If you sit offcenter, you will hear the image shifted toward one side. Listen to the
image of the sound between the speaker pair. You should localize it
midway between the monitors; that is, straight ahead.
5. If necessary, center the image by adjusting the left or right volume
control on your power amp.
When you do a mixdown, try to keep the listening level around 85
dBSPL—a fairly loud home listening level. As discovered by Fletcher and
Munson, we hear less bass in a program that is played quietly than in the
same program played loudly. If you mix a program while monitoring at,
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Practical Recording Techniques
say, 100 dBSPL, the same program will sound weak in the bass when
heard at a lower listening level—which is likely in the home. So, programs meant to be heard at 85 dBSPL should be mixed and monitored at
that level.
Loud monitoring also exaggerates the frequencies around 4 kHz.
A recording mixed loud may sound punchy, but the same recording
heard at a low volume will sound dull and lifeless.
Here’s another reason to avoid extreme monitor levels: Loud sustained sound can damage your hearing or cause temporary hearing loss
at certain frequencies. If you must do a loud playback for the musicians
(who are used to high SPLs in the studio), protect your ears by wearing
earplugs or leaving the room.
You can get a low-cost sound level meter from Radio Shack. Play a
musical program at 0 VU or 0 dB on the mixer meters and adjust the
monitor level to obtain an average reading of 85 dBSPL on the sound level
meter. Mark the monitor-level setting.
Before doing a mix, you may want to play some familiar commercial CDs over your monitors to remind yourself what a good tonal
balance sounds like. Listen to the amount of bass, midrange, and treble,
and try to match those in your mixes. But listen to several CDs, because
they vary.
While mixing, monitor the program alternately in stereo and mono
to make sure there are no out-of-phase signals that cancel certain frequencies in mono. Also beware of center-channel buildup: Instruments
or vocals that are panned to center in the stereo mix sound 3 dB louder
when monitored in mono than they do in stereo. That is, the balance
changes in mono—the center instruments are a little too loud. To prevent
this, don’t pan tracks hard left and hard right. Bring in the side images a
little so they will be louder in mono.
You’ll mix the tracks to sound good on your accurate monitors. But
also check the mix on small inexpensive speakers to see whether anything is missing or whether the mix changes drastically. Make sure that
bass instruments are recorded with enough edge or harmonics to be
audible on the smaller speakers. It’s a good idea to make a cassette or CD
copy of the mix for listening in a car, boom box, or compact stereo.
Headphones
Many home studios have the mixer and monitors in the same room as
the musicians. In this case, you monitor with quality headphones while
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Monitoring
5
recording and overdubbing, then monitor with speakers when you
mix. If you’re monitoring as the musicians are playing, block out
their sound by using closed-cup headphones or in-the-ear earphones.
You may find that headphones provide adequate isolation if the
music you’re recording is quiet. Some popular headphones for studio
monitoring are the Sony MDR-7506, AKG K240, and Sennheiser HD
280 Pro.
Compared to speakers, headphones have several advantages:
•
•
•
•
•
•
They cost much less.
There is no coloration from room acoustics.
The tone quality is the same in different environments.
They are convenient for on-location monitoring.
It’s easy to hear small changes in the mix.
Transients are sharper due to the absence of room reflections.
Headphones have several disadvantages:
•
•
•
•
•
•
They become uncomfortable after long listening sessions.
Cheap headphones have inaccurate tone quality.
Headphones don’t project bass notes through your body.
The bass response varies due to changing headphone pressure.
The sound is in your head rather than out front.
You hear no room reverberation, so you may add in too much or too
little artificial reverb.
• It’s difficult to judge the stereo spread. Over headphones, panned
signals tend not to sound as far off center as the same signals heard
over speakers. The same is true of stereo recordings made with a
coincident pair of mics.
Because speakers sound different from headphones, it’s best to do mixes
over speakers.
The Cue System
The cue system is a monitor system for musicians to use as they’re recording. It includes some of the aux knobs in your mixer, a small power amplifier, a headphone connector box, and headphones. Musicians often can’t
hear each other well in the studio, but they can listen over headphones
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Practical Recording Techniques
to hear each other in a good balance. Also, they can listen to previously
recorded tracks while overdubbing.
Headphones for a cue system should be durable and comfortable.
They should be closed-cup to avoid leakage into microphones. This is an
ideal situation; open-air phones may work well enough. Also, the cue
“phones” should have a smooth response to reduce listening fatigue, and
should play loud without burning out. Make sure they are all the same
model so each musician hears the same thing. A built-in volume control
is convenient.
A suggested cue system is shown in Figure 5.5. Connect a power
amp to an aux-send or monitor output of your mixer. The amp drives
several resistor-isolated headphones, which are in parallel.
If your mixer has a strong signal at its headphone jack, you can get
by with four headphone jacks in a small metal box wired in parallel and
connected to the mixer’s headphone jack.
Although some consoles can provide several independent cue
mixes, the ideal situation is to set up individual cue mixers near each
musician. Then they can set their own cue mix and listening level. The
inputs of these mixers are fed from the console output buses.
Suppose a vocalist sings into a microphone and hears that mic’s
signal over the cue headphones. If the singer’s voice and the headphone’s
sound are opposite in polarity, the voice partially cancels or sounds funny
in the headphones. Make sure that the voice and headphones are the
same polarity.
Here’s how. While talking into a mic and listening to it on headphones, reverse the ground and signal leads to the headphones connec-
Figure 5.5
84
A cue system.
Monitoring
5
tor. The position that gives the fullest, most solid sound in the headphones is correct.
All the headphones in your studio should be the same model, so that
everyone will hear with correct polarity.
Conclusion
Ultimately, what you hear from the monitors influences your recording
techniques and affects the quality of your recordings. So take the time to
plan and adjust the control-room acoustics. Choose and place the speakers carefully. Monitor at proper levels and listen on several systems. You’ll
be rewarded with a monitor system you can trust.
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6
MICROPHONES
What microphone is best for recording an orchestra? What’s a good snare
mic? Should the microphone be a condenser or dynamic, omni or
cardioid?
You can answer these questions more easily once you know the
types of microphones and understand their specs. First, it always pays to
get a high-quality microphone—which costs at least $100. The mic is a
source of your recorded signal. If that signal is noisy, distorted, or tonally
colored, you’ll be stuck with those flaws through the whole recording
process. Better get it right up front.
Even if you have a MIDI studio and get all your sounds from
samples or synthesizers, you still might need a good microphone for sampling, or to record vocals, sax, acoustic guitar, and so on.
A microphone is a transducer—a device that changes one form of
energy into another. Specifically, a mic changes sound into an electrical
signal. Your mixer amplifies and modifies this signal.
Transducer Types
Mics for recording can be grouped into three types depending on how
they convert sound to electricity: dynamic, ribbon, or condenser.
A dynamic mic capsule, or transducer, is shown in Figure 6.1. A coil
of wire attached to a diaphragm is suspended in a magnetic field. When
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Practical Recording Techniques
VOICE
COIL
DIAPHRAGM
+
– +
MAGNET
DIAPHRAGM
MOVEMENT
–
MAGNET
Figure 6.1
A dynamic transducer.
POLE PIECE
MAGNET
SIGNAL
RIBBON
FRONT
REAR
SIGNAL
Figure 6.2
A ribbon transducer.
sound waves vibrate the diaphragm, the coil vibrates in the magnetic
field and generates an electrical signal similar to the incoming sound
wave. Another name for a dynamic mic is moving-coil mic, but this term
is seldom used.
In a ribbon mic capsule, a thin metal foil or ribbon is suspended in
a magnetic field (Figure 6.2). Sound waves vibrate the ribbon in the field
and generate an electrical signal.
A condenser or capacitor mic capsule has a conductive diaphragm
and a metal backplate placed very close together (Figure 6.3). They are
charged with static electricity to form two plates of a capacitor. When
sound waves strike the diaphragm, it vibrates. This varies the spacing
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Microphones
6
+
–
DIAPHRAGM
DIAPHRAGM
MOVEMENT
– +
BACKPLATE
INSULATING
SPACER
Figure 6.3
A condenser transducer.
between the plates. In turn, this varies the capacitance and generates a
signal similar to the incoming sound wave. Because of its lower
diaphragm mass and higher damping, a condenser mic responds faster
than a dynamic mic to rapidly changing sound waves (transients).
Two types of condenser mic are true condenser and electret
condenser. In a true condenser mic (externally biased mic), the
diaphragm and backplate are charged with a voltage from a circuit
built into the mic. In an electret condenser mic, the diaphragm and
backplate are charged by an electret material, which is in the diaphragm
or on the backplate. Electrets and true condensers can sound equally
good, although some engineers prefer true condensers, which tend to cost
more.
A condenser mic needs a power supply to operate, such as a battery
or phantom power supply. Phantom power is 12 to 48 volts DC applied
to pins 2 and 3 of the mic connector through two equal resistors. The
microphone receives phantom power and sends audio signals on the
same two conductors. Many mixing consoles supply phantom power at
their mic input connectors. You simply plug the mic into the mixer to
power it. Dynamics and ribbons need no power supply. You can plug
these types of mics into a phantom supply without damage, unless either
signal conductor is accidentally shorted to the mic housing. Figure 6.4
shows a cutaway view of a typical dynamic vocal mic and condenser
instrument mic.
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Practical Recording Techniques
TYPICAL DYNAMIC VOCAL MIC
GRILLE
WIRES
MIC CAPSULE
CONNECTOR
SHOCK MOUNT
DIAPHRAGM
DIAPHRAGM
GRILLE
HOUSING
MAGNET
HOUSING
REAR PORT
CONNECTOR
CIRCUIT BOARD
TYPICAL CONDENSER INSTRUMENT MIC
Figure 6.4
Inside a typical dynamic vocal mic and condenser instrument mic.
General Traits of Each Transducer Type
Condenser
•
•
•
•
•
•
Wide, smooth frequency response
Detailed sound, extended highs
Omni type has excellent low-frequency response
Transient attacks sound sharp and clear
Preferred for acoustic instruments, cymbals, studio vocals
Can be miniaturized
Dynamic
•
•
•
•
•
•
90
Tends to have rougher response, but still quite usable
Rugged and reliable
Handles heat, cold, and high humidity
Handles high volume without distortion
Preferred for guitar amps and drums
If flat response, can take the “edge” off woodwinds and brass
Microphones
6
Ribbon
• Prized for its warm, smooth tone quality
• Delicate
• Complements digital recording
There are exceptions to the tendencies listed above. Some dynamics have
a smooth, wide-range frequency response. Some condensers are rugged
and handle high SPLs. It depends on the specs of the particular mic.
Track 13 on the enclosed CD demonstrates the sound of each transducer type.
Polar Pattern
Microphones also differ in the way they respond to sounds coming from
different directions. An omnidirectional microphone is equally sensitive
to sounds arriving from all directions. A unidirectional mic is most sensitive to sound arriving from one direction—in front of the mic—but
softens sounds entering the sides or rear of the mic. A bidirectional mic
is most sensitive to sounds arriving from two directions—in front of and
behind the mic—but rejects sounds entering the sides.
There are three types of unidirectional patterns: cardioid, supercardioid, and hypercardioid. A mic with a cardioid pattern is sensitive to
sounds arriving from a broad angle in front of the mic. It is about 6 dB
less sensitive at the sides, and about 15 to 25 dB less sensitive in the rear.
The supercardioid pattern is 8.7 dB less sensitive at the sides and has two
areas of least pickup at 125 degrees away from the front. The hypercardioid pattern is 12 dB less sensitive at the sides and has two areas of
least pickup at 110 degrees away from the front.
To hear how a cardioid pickup pattern works, talk into a cardioid
mic from all sides while listening to its output. Your reproduced voice is
loudest when you talk into the front of the mic, and softest when you talk
into the rear. Play CD track 14.
The super- and hypercardioid reject sound from the sides more than
the cardioid. They are more directional, but they pick up more sound
from the rear than the cardioid does.
A microphone’s polar pattern is a graph of its sensitivity versus the
angle at which sound comes into it. The polar pattern is plotted on polar
graph paper. Sensitivity is plotted as distance from the origin. Figure 6.5
shows various polar patterns.
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Practical Recording Techniques
Figure 6.5
incidence.
92
Various polar patterns. Sensitivity is plotted vs. angle of sound
Microphones
6
Traits of Various Polar Patterns
Omnidirectional
•
•
•
•
•
•
•
All-around pickup
Most pickup of room reverberation (play CD track 14)
Not much isolation unless you mike close
Low sensitivity to pops (explosive breath sounds)
Low handling noise
No up-close bass boost (proximity effect)
Extended low-frequency response in condenser mics—great for pipe
organ or bass drum in an orchestra or symphonic band
• Lower cost in general
Unidirectional (cardioid, supercardioid, hypercardioid)
•
•
•
•
•
•
Selective pickup
Rejection of room acoustics, background noise, and leakage
Good isolation—good separation between tracks
Up-close bass boost (except in mics that have holes in the handle)
Better gain-before-feedback in a sound-reinforcement system
Coincident or near-coincident stereo miking (explained in
Chapter 7)
Cardioid
• Broad-angle pickup of sources in front of the mic
• Maximum rejection of sound approaching the rear of the mic
Supercardioid
• Maximum difference between front hemisphere and rear hemisphere pickup (good for stage-floor miking)
• More isolation than a cardioid
• Less reverb pickup than a cardioid
Hypercardioid
• Maximum side rejection in a unidirectional mic
• Maximum isolation—maximum rejection of reverberation, leakage,
feedback, and background noise
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Practical Recording Techniques
Bidirectional
• Front and rear pickup, with side sounds rejected (for across-table
interviews or two-part vocal groups, for example)
• Maximum isolation of an orchestral section when miked overhead
• Blumlein stereo miking (two bidirectional mics crossed at 90
degrees)
In a good mic, the polar pattern should be about the same from 200 Hz
to 10 kHz. If not, you’ll hear off-axis coloration: the mic will have a different tone quality on and off axis. Small-diaphragm mics tend to have
less off-axis coloration than large-diaphragm mics.
You can get either the condenser or dynamic type with any kind of
polar pattern (except bidirectional dynamic). Ribbon mics are either bidirectional or hypercardioid. Some condenser mics come with switchable
patterns. Note that the shape of a mic does not indicate its polar pattern.
If a mic is end-addressed, you aim the end of the mic at the sound
source. If a mic is side-addressed, you aim the side of the mic at the sound
source. Figure 6.6 shows a typical side-addressed condenser mic with
switchable polar patterns.
Boundary mics that mount on a surface have a pattern that is halfomni (hemispherical), half-supercardioid, or half-cardioid (like an apple
sliced in half through its stem). The boundary mounting makes the mic
more directional so it picks up less room acoustics.
Frequency Response
As with other audio components, a microphone’s frequency response is
the range of frequencies that it will reproduce at an equal level (within a
tolerance, such as ±3 dB).
The following is a list of sound sources and the microphone frequency response that is adequate to record the source with high fidelity.
A wider range response works, too.
•
•
•
•
•
•
94
Most instruments: 80 Hz to 15 kHz
Bass instruments: 40 Hz to 9 kHz
Brass and voice: 80 Hz to 12 kHz
Piano: 40 Hz to 12 kHz
Cymbals and some percussion: 300 Hz to 15 or 20 kHz
Orchestra or symphonic band: 40 Hz to 15 kHz
Microphones
6
DIAPHRAGM
GRILLE
ELECTRONICS
Figure 6.6
A typical multi-pattern mic that is side-addressed.
If possible, use a mic with a response that rolls off below the lowest fundamental frequency of the instrument you’re recording. For example, the
frequency of the low-E string on an acoustic guitar is about 82 Hz. A mic
used on the acoustic guitar should roll off below that frequency to avoid
picking up low-frequency noise such as rumble from trucks and air conditioning. Some mics have a built-in low-cut switch for this purpose. Or
you can filter out the unneeded lows at your mixer.
A frequency-response curve is a graph of the mic’s output level in
dB at various frequencies. The output level at 1 kHz is placed at the
0 dB line on the graph, and the levels at other frequencies are so many
decibels above or below that reference level.
The shape of the response curve suggests how the mic sounds at a
certain distance from the sound source. (If the distance is not specified,
it’s probably 2 to 3 feet.) For example, a mic with a wide, flat response
reproduces the fundamental frequencies and harmonics in the same
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Practical Recording Techniques
proportion as the sound source. So a flat-response mic tends to provide
accurate, natural reproduction at that distance.
A rising high end or a “presence peak” around 5 to 10 kHz sounds
more crisp and articulate because it emphasizes the higher harmonics
(Figure 6.7). Play CD track 15. Sometimes this type of response is called
tailored or contoured. It’s popular for guitar amps and drums because it
adds punch and emphasizes attack. Some microphones have switches
that alter the frequency response.
Most uni- and bidirectional mics boost the bass when used within a
few inches of a sound source. You’ve heard how the sound gets bassy
when a vocalist sings right into the mic. This low-frequency boost related
to close mic placement is called the proximity effect, and it’s often plotted
on the frequency-response graph. Omni mics have no proximity effect;
they sound tonally the same at any distance.
The warmth created by proximity effect adds a pleasing fullness to
drums. In most recording situations, though, the proximity effect lends
an unnatural boomy or bassy sound to the instrument or voice picked up
by the mic. Some mics—multiple-D or variable-D types—are designed to
reduce it. These types have holes or slots in the mic handle. Some mics
have a bass-rolloff switch to compensate for the bass boost. Or you can
roll off the excess bass with your mixer’s equalizer until the sound is
natural. By doing so, you also reduce low-frequency leakage picked up
by the microphone.
Note that mic placement can greatly affect the recorded tone quality.
A flat-response mic does not always guarantee a natural sound because
mic placement has such a strong influence. Tonal effects of mic placement
are covered in Chapter 7.
Figure 6.7 An example of the frequency response of a microphone with proximity effect and a presence peak around 5 kHz.
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Microphones
6
Impedance (Z)
This spec is the mic’s effective output resistance at 1 kHz. A mic impedance between 150 and 600 ohms is low; 1000 to 4000 ohms is medium; and
above 25 kilohms is high.
Always use low-impedance mics. If you do, you can run long mic
cables without picking up hum or losing high frequencies. The input
impedance of a mixer mic input is about 1500 ohms. If it were the same
impedance as the mic, about 250 ohms, the mic would “load down” when
you plug it in. Loading down a mic makes it lose level, distort, or sound
thin. To prevent this, a mic input has an impedance much higher than
that of the microphone. But it’s still called a low-Z input.
More information on impedance is in Appendix E.
Maximum SPL
To understand this spec, first we need to understand sound pressure level
(SPL). It is a measure of the intensity of a sound. The quietest sound we
can hear, the threshold of hearing, is 0 dBSPL. Normal conversation at 1
foot measures about 70 dBSPL; painfully loud sound is above 120 dBSPL.
If the maximum SPL spec is 125 dBSPL, the mic starts to distort
when the instrument being miked is putting out 125 dBSPL at the mic.
A maximum SPL spec of 120 dB is good, 135 dB is very good, and 150 dB
is excellent.
Dynamic mics tend not to distort, even with very loud sounds. Some
condensers are just as good. Some have a pad you can switch in to
prevent distortion in the mic circuitry. Because a mic pad reduces signalto-noise ratio (S/N), use it only if the mic distorts.
Sensitivity
This spec tells how much output voltage a mic produces when driven by
a certain SPL. A high-sensitivity mic puts out a stronger signal (higher
voltage) than a low-sensitivity mic when both are exposed to an equally
loud sound.
A low-sensitivity mic needs more mixer gain than a high-sensitivity
mic. More gain usually results in more noise. When you record quiet
music at a distance (classical guitar, string quartet), use a mic of high sensitivity to override mixer noise. When you record loud music or mike
close, sensitivity matters little because the mic signal level is well above
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Practical Recording Techniques
the mixer noise floor. That is, the S/N is high. Listed below are typical
sensitivity specs for three transducer types:
• Condenser: 5.6 mV/Pa (high sensitivity)
• Dynamic: 1.8 mV/Pa (medium sensitivity)
• Ribbon or small dynamic: 1.1 mV/Pa (low sensitivity)
The louder the sound source, the higher the signal voltage the mic puts
out. A very loud instrument, such as a kick drum or guitar amp, can cause
a microphone to generate a signal strong enough to overload the mic
preamp in your mixer. That’s why most mixers have pads or input-gain
controls—to prevent preamp overload from hot mic signals.
Self-Noise
Self-noise or equivalent noise level is the electrical noise or hiss a mic produces. It’s the dBSPL of a sound source that would produce the same
output voltage that the noise does.
Usually the self-noise spec is A-weighted. That means the noise was
measured through a filter that makes the measurement correlate more
closely with the annoyance value. The filter rolls off low and high frequencies to simulate the frequency response of the ear.
An A-weighted self-noise spec of 14 dBSPL or less is excellent (quiet);
21 dB is very good, 28 dB is good; and 35 dB is fair—not good enough for
quality recording.
Because a dynamic mic has no active electronics to generate noise,
it has very low self-noise (hiss) compared to a condenser mic. So most
spec sheets for dynamic mics do not specify self-noise.
Signal-to-Noise Ratio
This is the difference in decibels between the mic’s sensitivity and its
self-noise. The higher the SPL of the sound source at the mic, the higher
the S/N. Given an SPL of 94 dB, an S/N spec of 74 dB is excellent; 64 dB
is good. The higher the S/N ratio, the cleaner (more noise-free) the signal,
and the greater the “reach” of the microphone.
Reach is the clear pickup of quiet, distant sounds due to high S/N.
Reach is not specified in data sheets because any mic can pick up a source
at any distance if the source is loud enough. For example, even a cheap
mic can reach several miles if the sound source is a thunderclap.
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Microphones
6
Polarity
The polarity spec relates the polarity of the electrical output signal to the
acoustic input signal. The standard is “pin 2 hot.” That is, the mic produces a positive voltage at pin 2 with respect to pin 3 when the sound
pressure pushes the diaphragm in (positive pressure).
Be sure that your mic cables do not reverse polarity. On both ends
of each cable, the wiring should be pin 1 shield, pin 2 red, pin 3 white or
black. Or the wiring on both ends should be pin 1 shield, pin 2 white, pin
3 black.
If some mic cables are correct polarity and some are reversed, and
you mix their mics to mono, the bass may cancel.
Microphone Types
The following sections describe several types of recording mics.
Large-Diaphragm Condenser Microphone
This is a condenser microphone, usually side-addressed, with a
diaphragm 1 inch or larger in diameter (Figure 6.6). It generally has
very good low-frequency response and low self-noise. Common uses are
studio vocals and acoustic instruments. Examples: AKG C12 VR, C414,
C2000B and C3000B; Audio-Technica AT2020/3035/4040, Audix SCX25,
Blue Blueberry, M-Audio Luna, CAD Equitek Series and M177, DPA 4041,
Lawson L47MP MKII and L251, Manley Gold Reference, Neumann U87,
U47 and TLM 103; Soundelux Elux 251, Shure KSM Series, MXL V67G,
V69, 900, 2001 and 2003; Rode NT1A, Studio Projects B and C Series,
Samson CL7 and C01, Nady SCM 950 and 100, M-Audio Luna and Nova,
and Behringer B1 and B2.
Small-Diaphragm Condenser Microphone
This is a stick-shaped or “pencil” cardioid condenser microphone, usually
end-addressed, with a diaphragm under 1 inch in diameter (Figure 6.4).
It generally has very good transient response and detail, making it a fine
choice for close miking acoustic instruments—especially cymbals,
acoustic guitar, and piano. Examples: AKG C 451 B; Audio-Technica AT
3031 and AT 4051a; Audix SCX1, ADX50, and ADX51; CAD Equitek e60;
M-Audio Pulsar; Samson C02; Crown CM-700; DPA 4006; Neumann KM
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Practical Recording Techniques
184; Sennheiser e614 and MKH50; Shure KSM109/SL, KSM137/Sl and
SM81; MXL 600 and 603S; Behringer B5 with cardioid capsule; and Studio
Projects C4.
Dynamic Instrument Microphone
This is a stick-shaped dynamic microphone, end-addressed (Figure 6.4).
Although it may have a flat response, it generally has a presence peak
and some low-frequency rolloff to prevent boominess when used up
close. It’s often used on drums and guitar amps. Examples: Shure SM57,
AKG D112 (kick drum), Audio-Technica AT AE2500 (kick), Electro-Voice
N/D868 (kick), Audix D1 through D6 and I-5, and Sennheiser MD421,
e604 and e602 (kick).
Live-Vocal Microphone
This unidirectional mic is shaped like an ice-cream cone because of its
large grille used to reduce breath pops. It can be a condenser, dynamic,
or ribbon type, and it usually has a presence peak and some lowfrequency rolloff. Examples: Shure SM58 and Beta 58, Shure SM85 and
SM87, AKG D3800, Audix OM5, Beyerdynamic M88 TG, Crown CM200A, EV N-Dym Series, and Neumann KMS 105.
Ribbon Microphone
This mic can be side- or end-addressed. It generally is used wherever you
want a warm, smooth tone quality (sometimes with reduced highs).
Examples: models by Beyerdynamic, Coles, Royer, and AEA.
Boundary Microphone
Boundary mics are designed to be used on surfaces. Tape them to the
underside of a piano lid, or tape them to the wall for pickup of room
ambience. They can be used on hard baffles between instruments, or on
panels to make the mics directional. A boundary mic uses a mini condenser mic capsule mounted very near a sound-reflecting plate or boundary (Figure 6.8). Because of this construction, the mic picks up direct
sound and reflected sound at the same time, in-phase at all frequencies.
So you get a smooth response free of phase cancellations. A conventional
mic near a surface sounds colored; a boundary mic on a surface sounds
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Microphones
Figure 6.8
6
Typical PZM construction.
natural. Examples: AKG C 562 BL, Audio-Technica AT 841a, Beyerdynamic MPC 22, Crown PZM-30D and PZM-6D, and Shure Beta 91.
Other benefits are a wide, smooth frequency response free of phase
cancellations, excellent clarity and reach, and the same tone quality anywhere around the mic. The polar pattern is half-omni or hemispherical.
Some boundary mics have a half-cardioid or half-supercardioid polar
pattern. They work great on a conference table, or near the front edge of
a stage floor to pick up drama or musicals.
Miniature Microphone
Mini condenser mics can be attached to drum rims, flutes, horns, acoustic
guitars, fiddles, and so on. Their tone quality is about as good as larger
studio microphones and the price is relatively low. With these tiny units
you can mike a band in concert without cluttering the stage with boom
stands (Figure 6.9), or you can mike a whole drum set with two or three
of these. Although you lose individual control of each drum in the mix,
the cost is low and the sound is quite good with some bass and treble
boost. Compared to large mics, mini mics tend to have more noise (hiss)
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Practical Recording Techniques
Figure 6.9
A mini mic is the size of a penny.
in distant-miking applications. A lavalier mic is a mini mic worn on the
chest to pick up speech from a newscaster or a wandering lecturer. Examples: AKG Micro Mic Series, Shure Beta 98S, Audix M1245 and Micro-D,
Countryman Isomax B6, Crown GLM-100, DPA 4060, and Sennheiser
e608.
Stereo Microphone
A stereo microphone combines two directional mic capsules in a single
housing for convenient stereo recording (Figure 6.10). Simply place the
mic a suitable distance and height from the sound source, and you’ll get
a stereo recording with little fuss. Examples: AKG C426 B Comb, AudioTechnica AT825 and AT822, Crown SASS-P MKII, Neumann SM69, Shure
VP88, Nady RSM-2, AEA R88, and Royer SF-12.
Because there is no spacing between the mic capsules, there also is
no delay or phase shift between their signals. Coincident stereo microphones are mono-compatible—the frequency response is the same in
mono and stereo—because there are no phase cancellations if the two
channels are combined.
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Microphones
Figure 6.10
6
A stereo microphone.
Digital Microphone
This condenser microphone has a built-in analog-to-digital converter. It
is usually side-addressed, has a large diaphragm, has a flat response, and
very low self-noise. Its output is a digital signal, which is immune to
picking up hum. Examples: Beyerdynamic MCD 100, and Neumann
Solution-D.
Headworn Microphone
This microphone is used for a live performance which might be recorded.
It is a small condenser mic worn on the head, either omni- or unidirectional. The headworn mic allows the performer freedom of movement on
stage. Some models provide excellent gain before feedback and isolation.
Examples: AKG C 420, Audio-Technica ATM73, Countryman Isomax E6,
and Crown CM-311A.
Microphone Selection
Table 6.1 is a guide to choosing a mic based on your requirements.
Suppose you want to record a grand piano playing with several
other instruments. You need the microphone to reduce leakage. Table 6.1
recommends a unidirectional mic or an omni mic up close. For this particular piano, you also want a natural sound, for which the table suggests
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Practical Recording Techniques
Table 6.1
Mic Application Guide
Requirement
Characteristic
Natural, smooth tone quality
Bright, present tone quality
Extended lows
Flat frequency response
Bright, present tone quality
Omni condenser or dynamic with good
low-frequency response
Condenser
Dynamic
Directional mic
Omni mic, or directional mic with sound
holes in the handle
Directional mics
Extended highs (detailed sound)
Reduced “edge” or detail
Boosted bass up close
Flat bass response up close
Reduced pickup of leakage, feedback,
and room acoustics
Enhanced pickup of room acoustics
Miking close to a surface, even
coverage of moving sources or
large sources, inconspicuous mic
Coincident or near-coincident stereo
(see Chapter 18)
Extra ruggedness
Reduced handling noise
Reduced breath popping
Distortion-free pickup of very loud
sounds
Low self-noise, high sensitivity,
noise-free pickup of quiet sounds
Omni mics
Boundary mic
Stereo mic
Dynamic mic
Omni mic, or unidirectional with shock mount
Omni mic, or unidirectional with pop filter
Condenser with high maximum SPL spec,
or dynamic
Large-diaphragm condenser mic
a mic with a flat response. You want a detailed sound, so a condenser mic
is the choice. A microphone with all these characteristics is a flat-response,
unidirectional condenser mic. If you’re miking close to a surface (the
piano lid), a boundary mic is recommended.
Now suppose you’re recording an acoustic guitar on stage, and the
guitarist roams around. This is a moving sound source, for which the
table recommends a mini mic attached to the guitar. Feedback and
leakage are not a problem because you’re miking close, so you can use
an omni mic. Thus, an omni condenser mic is a good choice for this
application.
For a home studio, a suggested first choice is a cardioid condenser
mic with a flat frequency response. This type of mic is especially good
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Microphones
6
for studio vocals, cymbals, percussion, and acoustic instruments. Remember that the mic needs a power supply to operate, such as a battery or
phantom power supply.
Your second choice of microphone for a home studio is a cardioid
dynamic microphone with a presence peak in the frequency response.
This type is good for drums and guitar amps. I recommend cardioid over
omni for a home studio. The cardioid pattern rejects the leakage, background noise, and room reverb often found in home studios. An omni
mic, however, can do that, too, if you mike close enough. Also, omni mics
tend to provide a more natural sound at lower cost, and they have no
proximity effect.
Mic Accessories
There are many devices used with microphones to route their signals or
to make them more useful. These include pop filters, stands and booms,
shock mounts, cables and connectors, stage boxes and snakes, and
splitters.
Pop Filter
A much needed accessory for a vocalist’s microphone is a pop filter or
windscreen. It usually is a foam “sock” that you put over the mic. Some
microphones have pop filters or ball-shaped grilles built in.
Why is it needed? When a vocalist sings a word starting with “p,”
“b,” or “t” sounds, a turbulent puff of air is forced from the mouth. A
microphone placed close to the mouth is hit by this air puff, resulting in
a thump or little explosion called a pop. The windscreen reduces this
problem.
The best type of pop filter is a nylon screen in a hoop, or a
perforated-metal disk, placed a few inches from the mic.
You can also reduce pop by placing the mic above or to the side of
the mouth, or by using an omni mic. CD track 16 demonstrates how a pop
filter or mic placement can prevent breath pops.
Stands and Booms
Stands and booms hold the microphones and let you position them as
desired. A mic stand has a heavy metal base that supports a vertical pipe.
At the top of the pipe is a rotating clutch that lets you adjust the height
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Practical Recording Techniques
of a smaller telescoping pipe inside the large one. The top of the small
pipe has a standard 5/8-inch 27 thread, which screws into a mic stand
adapter.
A boom is a long horizontal pipe that attaches to the vertical pipe.
The angle and length of the boom are adjustable. The end of the boom is
threaded to accept a mic stand adapter, and the opposite end is weighted
to balance the weight of the microphone.
Shock Mount
A shock mount holds a mic in a resilient suspension to isolate the mic
from mechanical vibrations, such as floor thumps and mic-stand bumps.
Many mics have an internal shock mount which isolates the mic
capsule from its housing; this reduces handling noise as well as stand
thumps.
Cables and Connectors
Mic cables carry the electrical signal from the mic to the mixing console,
mic preamp, or recorder. With low-impedance mics, you can use hundreds of feet of cable without hum pickup or high-frequency loss. Some
mics have a permanently attached cable for convenience and low cost;
others have a connector in the handle to accept a separate mic cable. The
second method is preferred for serious recording because if the cable
breaks, you have to repair or replace only the cable, not the whole microphone.
Mic cables are made of one or two insulated conductors surrounded
by a fine-wire mesh shield to keep out electrostatic hum. If you hear a
loud buzz when you plug in a microphone, check that the shield is
securely soldered in place.
After acquiring a microphone, you may need to wire its 2-conductor shielded cable to a 3-pin XLR audio connector. Here are the solder
connections:
1. Pin 1: Shield
2. Pin 2: “Hot” or “in-polarity” lead (usually red or white)
3. Pin 3: “Cold” or “out-of-polarity” lead (usually black)
If the mic output is a 3-pin XLR, but your recorder or mixer mic input is
an unbalanced phone jack, a different wiring is needed:
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Microphones
6
1. Phone-plug tip (the short terminal): Hot lead
2. Phone-plug sleeve (the long terminal): Shield and cold lead
Wind your mic cables onto a large spool, which can be found in the electrical section of hardware stores. Plug the cables together as you wind
them.
Snake
It is messy and time-consuming to run mic cables from several mics
all the way to a mixer. Instead, you can plug all your mics into a stage
box with several connectors (Figure 6.11). The snake—a thick multiconductor cable—carries the signals to the mixer. At the mixer end, the
cable divides into several mic connectors that plug into the mixer.
Splitter
When you record a band in concert, you might want to feed each mic’s
signal to your recording mixer and to the band’s PA and monitor mixers.
A mic splitter does the job. For each microphone channel, it has one XLR
input for a microphone, a “direct” XLR output wired to the input, and
STAGE BOX
CONNECTORS TO
MIC CABLES
SNAKE
CONNECTORS TO MIXER
Figure 6.11
A stage box and snake.
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Practical Recording Techniques
one or more transformer-isolated XLR outputs with a ground-lift switch.
The mixer that provides phantom power must be connected to the direct
XLR output.
Summary
We talked about some mic types, specs, and accessories. You should have
a better idea about what kind of microphone to choose for your own
applications.
Mic manufacturers are happy to send you free catalogs and application notes, which are also available on mic company Web sites. Mic
dealers also may have this literature.
Remember, you can use any microphone on any instrument if it
sounds good to you. Just try it and see if you like it. To make high-quality
recordings, though, you need good mics with a smooth, wide-range frequency response, low noise, and low distortion.
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7
MICROPHONE TECHNIQUE
BASICS
Suppose you’re going to mike a singer, a sax, or a guitar. Which mic
should you choose? Where should you place it?
Your mic technique has a powerful effect on the sound of your
recordings. In this chapter we’ll look at some general principles of miking
that apply to all situations. Chapter 8 covers common mic techniques for
specific instruments.
Which Mic Should I Use?
Is there a “right” mic to use on a piano, a kick drum, or a guitar amp?
No. Every microphone sounds different, and you choose the one that
gives you the sound you want. Still, it helps to know about two main
characteristics of mics that affect the sound: frequency response and polar
pattern.
Most condenser mics have an extended high-frequency response—
they reproduce sounds up to 15 or 20 kHz. This makes them great for
cymbals or other instruments that need a detailed sound, such as acoustic
guitar, strings, piano, and voice. Dynamic moving-coil microphones have
a response good enough for drums, guitar amps, horns, and woodwinds.
Loud drums and guitar amps sound dull if recorded with a flat-response
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Practical Recording Techniques
mic; a mic with a presence peak (a boost around 5 kHz) gives more edge
or punch.
Suppose you are choosing a microphone for a particular instrument.
In general, the frequency response of the mic should cover at least the
frequencies produced by that instrument. For example, an acoustic guitar
produces fundamental frequencies from 82 Hz to about 1 kHz, and produces harmonics from about 1 to 15 kHz. So a mic used on an acoustic
guitar should have a frequency response of at least 82 Hz to 15 kHz if you
want to record the guitar accurately. Table 7.1 shows the frequency ranges
of various instruments.
The polar pattern of a mic affects how much leakage and ambience
it picks up. Leakage is unwanted sound from instruments other than the
one at which the mic is aimed. Ambience is the acoustics of the record-
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Table 7.1
Frequency Ranges of Various Musical Instruments
Instrument
Fundamentals (Hz)
Harmonics (kHz)
Flute
Oboe
Clarinet
Bassoon
Trumpet
French horn
Trombone
Tuba
Snare drum
Kick drum
Cymbals
Violin
Viola
Cello
Acoustic bass
Electric bass
Acoustic guitar
Electric guitar
Electric guitar
Piano
Bass (voice)
Tenor (voice)
Alto (voice)
Soprano (voice)
261–2349
261–1568
165–1568
62–587
165–988
87–880
73–587
49–587
100–200
30–147
300–587
196–3136
131–1175
65–698
41–294
41–300
82–988
82–1319
82–1319
28–4196
87–392
131–494
175–698
247–1175
3–8
2–12
2–10
1–7
1–7.5
1–6
1–7.5
1–4
1–20
1–6
1–15
4–15
2–8.5
1–6.5
1–5
1–7
1–15
1–3.5 (through amp)
1–15 (direct)
5–8
1–12
1–12
2–12
2–12
Microphone Technique Basics
7
ing room—its early reflections and reverb. The more leakage and ambience you pick up, the more distant the instrument sounds.
An omni mic picks up more ambience and leakage than a directional
mic when both are the same distance from an instrument. So an omni
tends to sound more distant. To compensate, you have to mike closer with
an omni.
How Many Mics?
The number of mics you need varies with what you’re recording. If you
want to record an overall acoustic blend of the instruments and room
ambience, use just two microphones or a stereo mic (Figure 7.1). This
method works great on an orchestra, symphonic band, choir, string
quartet, pipe organ, small folk group, or a piano/voice recital. Stereo
miking is covered in detail later in this chapter.
To record a pop-music group, you mike each instrument or instrumental section. Then you adjust the mixer volume control for each mic
to control the balance between instruments (Figure 7.2).
To get the clearest sound, don’t use two mics when one will do the
job. Sometimes you can pick up two or more sound sources with one mic
(Figure 7.3). You could mike a brass section of four players with one mic
on four players, or with two mics on every two players. Or mike a choir
Figure 7.1
Overall miking of a musical ensemble with two distant microphones.
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Practical Recording Techniques
Figure 7.2
Individual miking with multiple close mics and a mixer.
Figure 7.3
Multiple miking with several sound sources on each microphone.
in a studio in four groups: put one mic on the basses, one on the sopranos, and so on.
Picking up more than one instrument with one mic has a problem:
during mixdown, you can’t adjust the balance among instruments
recorded on the same track. You have to balance the instruments before
recording them. Monitor the mic, and listen to see if any instrument is
too quiet. If so, move it closer to the mic.
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Microphone Technique Basics
7
How Close Should I Place the Mic?
Once you’ve chosen a mic for an instrument, how close should the mic
be? Mike a few inches away to get a tight, present sound; mike farther
away for a distant, spacious sound. (Try it to hear the effect.) Play CD
track 17. The farther a mic is from the instrument, the more ambience,
leakage, and background noise it picks up. So mike close to reject these
unwanted sounds. Mike farther away to add a live, loose, airy feel to
overdubs of drums, lead-guitar solos, horns, etc.
Close miking sounds close; distant miking sounds distant. Here’s
why. If you put a mic close to an instrument, the sound at the mic is loud.
So you need to turn up the mic gain on your mixer only a little to get a
full recording level. And because the gain is low, you pick up very little
reverb, leakage, and background noise (Figure 7.4A).
If you put a mic far from an instrument, the sound at the mic is quiet.
You’ll need to turn up the mic gain a lot to get a full recording level. And
because the gain is high, you pick up a lot of reverb, leakage, and background noise (Figure 7.4B).
If the mic is very far away—maybe 10 feet—it’s called an ambience
mic or room mic. It picks up mostly room reverb. A popular mic for ambience is a boundary microphone taped to the wall. You mix it with the
Figure 7.4 (A) A close microphone picks up mainly direct sound, which results
in a close sound quality. (B) A distant microphone picks up mainly reflected sound,
which results in a distant sound quality.
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Practical Recording Techniques
usual close mics to add a sense of space. Use two for stereo. When you
record a live concert, you might want to place ambience mics over the
audience, aiming at them from the front of the hall, to pick up the crowd
reaction and the hall acoustics.
Classical music is always recorded at a distance (about 4 to 20 feet
away) so that the mics will pick up reverb from the concert hall. It’s a
desirable part of the sound.
Leakage
Suppose you’re close-miking a drum set and a piano at the same time
(Figure 7.5). When you listen to the drum mics alone, you hear a close,
clear sound. But when you mix in the piano mic, that nice, tight drum
sound degrades into a distant, muddy sound. That’s because the drum
sound leaked into the piano mic, which picked up a distant drum sound
from across the room. CD track 11 is an example of leakage.
There are many ways to reduce leakage:
• Mike each instrument closely. That way the sound level at each mic
is high. Then you can turn down the mixer gain of each mic, which
reduces leakage at the same time.
• Overdub each instrument one at a time.
• Record direct.
• Filter out frequencies above and below the range of each instrument.
• Use directional mics (cardioid, etc.) instead of omni mics.
Figure 7.5 Example of leakage. The piano mic picks up leakage from the
drums, which changes the close drum sound to distant.
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Microphone Technique Basics
7
• Record in a large, fairly dead studio. In such a room, leakage
reflected from the walls is weak.
• Put portable walls (goboes) between instruments.
Don’t Mike Too Close
Miking too close can color the recorded tone quality of an instrument. If
you mike very close, you might hear a bassy or honky tone instead of a
natural sound.
Why? Most musical instruments are designed to sound best at a distance, at least 1-1/2 feet away. The sound of an instrument needs some
space to develop. A mic placed a foot or two away tends to pick up a
well-balanced, natural sound. That is, it picks up a blend of all the parts
of the instrument that contribute to its character or timbre.
Think of a musical instrument as a loudspeaker with a woofer,
midrange, and tweeter. If you place a mic a few feet away, it will pick up
the sound of the loudspeaker accurately. But if you place the mic close to
the woofer, the sound will be bassy. Similarly, if you mike close to an
instrument, you emphasize the part of the instrument that the microphone is near. The tone quality picked up very close may not reflect the
tone quality of the entire instrument.
Suppose you place a mic next to the sound hole of an acoustic
guitar, which resonates around 80 to 100 Hz. A microphone placed there
hears this bassy resonance, giving a boomy recorded timbre that does
not exist at a greater miking distance. To make the guitar sound more
natural when miked close to the sound hole, you need to roll off the
excess bass on your mixer, or use a mic with a bass rolloff in its frequency
response.
The sax projects highs from the bell, but projects mids and lows from
the tone holes. So if you mike close to the bell, you miss the warmth and
body from the tone holes. All that’s left at the bell is a harsh tone quality.
You might like that sound, but if not, move the mic out and up to pick
up the entire instrument. If leakage forces you to mike close, change the
mic or use equalization (EQ).
Usually, you get a natural sound if you put the mic as far from the
source as the source is big. That way, the mic picks up all the soundradiating parts of the instrument about equally. For example, if the body
of an acoustic guitar is 18 inches long, place the mic 18 inches away to
get a natural tonal balance. If this sounds too distant or hollow, move in
a little closer.
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Practical Recording Techniques
Where Should I Place the Mic?
Suppose you have a mic placed a certain distance from an instrument. If
you move the mic left, right, up, or down, you change the recorded tone
quality. In one spot, the instrument might sound bassy; in another spot,
it might sound natural, and so on. So, to find a good mic position, simply
place the mic in different locations—and monitor the results—until you
find one that sounds good to you.
Here’s another way to do the same thing. Close one ear with your
finger, listen to the instrument with the other ear, and move around until
you find a spot that sounds good. Put the mic there. Then make a recording and see if it sounds the same as what you heard live. Don’t try this
with kick drums or screaming guitar amps!
Why does moving the mic change the tone quality? A musical instrument radiates a different tone quality in each direction. Also, each part of
the instrument produces a different tone quality. For example, Figure 7.6
shows the tonal balances picked up at various spots near a guitar. CD
track 18 illustrates the effect of mic placement on guitar tonal balance. CD track
19 demonstrates close and distant stereo miking of the acoustic guitar.
NATURAL
NATURAL
BASSY
MELLOW
Figure 7.6
116
Microphone placement affects the recorded tonal balance.
Microphone Technique Basics
7
Other instruments work the same way. A trumpet radiates strong
highs directly out of the bell, but does not project them to the sides. So a
trumpet sounds bright when miked on-axis to the bell and sounds more
natural or mellow when miked off to one side. A grand piano miked one
foot over the middle strings sounds fairly natural, under the soundboard
sounds bassy and dull, and in a sound hole it sounds mid-rangey.
It pays to experiment with all sorts of mic positions until you find a
sound you like. There is no one right way to place the mics because you
place them to get the tonal balance you want.
On-Surface Techniques
Sometimes you’re forced to place a mic near a hard reflecting surface.
Examples:
• Recording drama or opera with the mics near the stage floor.
• Recording an instrument that has hard surfaces around it.
• Recording a piano with the mic close to the lid.
In these cases, you’ll often pick up an unnatural, filtered tone quality.
Here’s why. Sound travels to the microphone via two paths: directly from
the sound source, and reflected off the nearby surface (Figure 7.7).
SOUND
SOURCE
DIRECT
MICROPHONE
REFLECTED
SURFACE
dB
FREQUENCY
Figure 7.7 A mic placed near a surface picks up direct sound and a delayed
reflection, which gives a comb-filter frequency response.
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Practical Recording Techniques
Because of its longer travel path, the reflected sound is delayed compared
to the direct sound. The direct and delayed sound waves combine at the
mic, which causes phase cancellations of various frequencies. The series
of peaks and dips in the response is called a comb-filter effect, and it
sounds like mild flanging.
Boundary mics solve the problem. In a boundary mic, the
diaphragm is very close to the reflecting surface so that there is no delay
in the reflected sound. Direct and reflected sounds add in-phase over the
audible range of frequencies, resulting in a flat response (Figure 7.8). Play
CD track 20.
You might tape an omni boundary mic to the underside of a piano
lid, to a hard-surfaced panel, or to a wall for ambience pickup. A unidirectional boundary mic works great on a stage floor to pick up drama.
A group of these mics will clearly pick up people at a conference table.
CLOSE-UP
VIEW
SOUND
SOURCE
MIC CAPSULE
REFLECTED
SOUND
BOUNDARY MICROPHONE
dB
FREQUENCY
Figure 7.8
in phase.
118
A boundary mic on the surface picks up direct and reflected sounds
Microphone Technique Basics
7
The Three-to-One Rule
Let’s say you’re miking several instruments, each with its own mic. If you
place the musicians too close together, the sound will be blurred. But if
you spread out the musicians and mike them close, the sound will be
clearer.
Specifically, try to space the mics at least three times the mic-tosource distance (as in Figure 7.9). This is called the 3:1 rule. For example,
if two mics are each placed 1 foot from their sound sources, the mics
should be at least 3 feet apart. This will prevent the blurred, colored
sound caused by phase cancellations between mics. Play CD track 21.
The mics can be closer together than 3:1 if you use two cardioid mics
aiming in opposite directions.
Suppose you’re recording a singer/guitarist. There’s a mic on the
singer and a mic on the acoustic guitar. The vocal picked up by the guitar
mic is delayed because the vocal sound travels a longer path to that mic.
The two vocal signals in the mix—direct and delayed—interfere with
each other and make a hollow sound.
Try these solutions:
• Mike the voice and guitar very close. Roll off the excess bass with
your mixer’s EQ. Maybe use a pickup on the guitar instead of a mic.
• Place two bidirectional mics so the tops of their grilles touch. This
gets rid of any delay between their signals. Aim the “dead” side of
3D OR GREATER
D
D
Figure 7.9 The 3:1 rule of microphone placement avoids phase interference
between microphone signals.
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Practical Recording Techniques
the vocal mic at the guitar; aim the dead side of the guitar mic at the
mouth.
• Use just one mic midway between the mouth and guitar. Adjust the
balance by changing the mic’s height.
• Delay the vocal mic signal by about 1 msec. Then the signals of the
two mics will be more in-phase, preventing phase cancellations
when they are mixed to the same channel.
Off-Axis Coloration
Some mics have off-axis coloration—a dull or colored effect on sound
sources that are not directly in front of the mic. Try to aim the mic at
sound sources that put out high frequencies, such as cymbals. When you
pick up a large source such as an orchestra, use a mic that has the same
response over a wide angle. Such a mic has similar polar patterns at
middle and high frequencies. Most large-diaphragm mics have more offaxis coloration than smaller mics (under 1 inch).
Stereo Mic Techniques
Stereo mic techniques capture the sound of a musical group as a whole,
using only two or three microphones. When you play back a stereo
recording, you hear phantom images of the instruments in various spots
between the speakers. These image locations—left to right, front to
back—correspond to the instrument locations during the recording
session.
Stereo miking is the preferred way to record classical-music ensembles and soloists. In the studio, you can stereo-mike a piano, drum set
cymbals, vibraphone, harmony singers, or other large sound sources.
Goals of Stereo Miking
One goal is accurate localization. That is, instruments in the center of the
group are reproduced midway between the two speakers. Instruments at
the sides of the group are heard from the left or right speaker. Instruments halfway to one side are heard halfway to one side, and so on.
Figure 7.10 shows three stereo localization effects. Figure 7.10A
shows some instrument positions in an orchestra: left, left-center, center,
right-center, right. In Figure 7.10B, the reproduced images of these instru-
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Microphone Technique Basics
7
Figure 7.10 Stereo localization effects. (A) Orchestra instrument locations (top
view). (B) Images localized accurately between speakers (the listener’s perception). (C) Narrow stage effect. (D) Exaggerated separation effect.
ments are accurately localized between the speakers. The stereo spread,
or stage width, extends from speaker to speaker. (You might want to
record a string quartet with a narrower spread.)
If you space or angle the mics too close together, you get a narrow
stage effect (Figure 7.10C). If you space or angle the mics too far apart,
you hear exaggerated separation (Figure 7.10D). That is, instruments
halfway to one side are heard near the left or right speaker.
To judge stereo effects, you have to sit exactly between your monitor
speakers (the same distance from each). Sit as far from the speakers as
the spacing between them. Then the speakers appear to be 60 degrees
apart. This is about the same angle an orchestra fills when viewed from
a typical ideal seat in the audience (say, tenth row center). If you sit offcenter, the images shift toward the side on which you’re sitting and are
less sharp.
Types of Stereo Mic Techniques
To make a stereo recording, you use one of these basic techniques:
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Practical Recording Techniques
•
•
•
•
Coincident pair (XY or MS)
Spaced pair (AB)
Near-coincident pair (ORTF, etc.)
Baffled pair (sphere, OSS, SASS, PZM wedge, etc.)
Let’s look at each technique.
Coincident Pair
With this method, you mount two directional mics with grilles touching,
diaphragms one above the other, and angled apart (Figure 7.11). For
example, mount two cardioid mics with one grille above the other, and
angle them 120 degrees apart. You can use other patterns too: supercardioid, hypercardioid, or bidirectional. The wider the angle between mics,
the wider the stereo spread.
How does this technique make images you can localize? A directional mic is most sensitive to sounds in front of the mic (on-axis) and
progressively less sensitive to sounds arriving off-axis. That is, a directional mic puts out a high-level signal from the sound source it’s aimed
at, and produces lower-level signals from other sound sources.
The coincident pair uses two directional mics that are angled symmetrically from the center line (Figure 7.11). Instruments in the center of
the group make the same signal from each mic. During playback, you
hear a phantom image of the center instruments midway between your
Figure 7.11
122
Coincident-pair technique.
Microphone Technique Basics
7
speakers. That’s because identical signals in each channel produce an
image in the center.
If an instrument is off-center to the right, it is more on-axis to the
right-aiming mic than to the left-aiming mic. So the right mic will produce
a higher level signal than the left mic. During playback of this recording,
the right speaker will play at a higher level than the left speaker. This
reproduces the image off-center to the right—where the instrument was
during recording.
The coincident pair codes instrument positions into level differences
between channels. During playback, the brain decodes these level differences back into corresponding image locations. A pan pot in a mixing
console works on the same principle. If one channel is 15 to 20 dB louder
than the other, the image shifts all the way to the louder speaker.
Suppose we want the right side of the orchestra to be reproduced at
the right speaker. That means the far-right musicians must produce a
signal level 20 dB higher from the right mic than from the left mic. This
happens when the mics are angled far enough apart. The correct angle
depends on the polar pattern.
Instruments partway off center produce interchannel level differences less than 20 dB, so you hear them partway off center.
Listening tests have shown that coincident cardioid mics tend to
reproduce the musical group with a narrow stereo spread. That is, the
group does not spread all the way between speakers.
A coincident-pair method with excellent localization is the Blumlein
array. It uses two bidirectional mics angled 90 degrees apart and facing
the left and right sides of the group.
A special form of the coincident-pair technique is Mid-Side or MS
(Figure 7.12). In this method, a cardioid or omni mic faces the middle of
the orchestra. A matrix circuit sums and differences the cardioid mic with
a bidirectional mic aiming to the sides. This produces left- and rightchannel signals. You can remotely control the stereo spread by changing
the ratio of the mid signal to the side signal. This remote control is useful
at live concerts, where you can’t physically adjust the mics during the
concert. MS localization can be accurate.
To make coincident recordings sound more spacious, boost the bass
4 dB (+2 dB at 600 Hz) in the L–R or side signal.
A recording made with coincident mics is mono-compatible. That is,
the frequency response is the same in mono or stereo. Because the mics
occupy almost the same point in space, there is no time or phase difference between their signals. And when you combine them to mono, there
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Practical Recording Techniques
Figure 7.12
Mid-side (MS) technique.
Figure 7.13
Spaced-pair technique.
are no phase cancellations to degrade the frequency response. If you
expect that your recordings will be heard in mono (say, on TV), then
you’ll probably want to use coincident methods.
Spaced Pair
Here, you mount two identical mics several feet apart and aim them
straight ahead (Figure 7.13). The mics can have any polar pattern, but
omni is most popular for this method. The greater the spacing between
mics, the greater the stereo spread.
How does this method work? Instruments in the center of the group
make the same signal from each mic. When you play back this recording,
you hear a phantom image of the center instruments midway between
your speakers.
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Microphone Technique Basics
7
If an instrument is off-center, it is closer to one mic than the other,
so its sound reaches the closer microphone before it reaches the other one.
Both mics make about the same signal, except that one mic signal is
delayed compared with the other.
If you send a signal to two speakers with one channel delayed, the
sound image shifts off center. With a spaced-pair recording, off-center
instruments produce a delay in one mic channel, so they are reproduced
off center.
The spaced pair codes instrument positions into time differences
between channels. During playback, the brain decodes these time differences back into corresponding image locations.
A delay of 1.2 msec is enough to shift an image all the way to one
speaker. You can use this fact when you set up the mics. Suppose you
want to hear the right side of the orchestra from the right speaker. The
sound from the right-side musicians must reach the right mic about
1.2 msec before it reaches the left mic. To make this happen, space
the mics about 2 to 3 feet apart. This spacing makes the correct delay to
place right-side instruments at the right speaker. Instruments partway off
center make interchannel delays less than 1.2 msec, so they are reproduced partway off center.
If the spacing between mics is, say, 12 feet, then instruments that are
slightly off center produce delays between channels that are greater than
1.2 msec. This places their images at the left or right speaker. I call this
“exaggerated separation” or a “ping-pong” effect (Figure 7.10D).
On the other hand, if the mics are too close together, the delays produced will be too small to provide much stereo spread. Also, the mics
will tend to emphasize instruments in the center because the mics are
closest to them.
To record a good musical balance of an orchestra, you need to space
the mics about 10 or 12 feet apart. But then you get too much separation.
You could place a third mic midway between the outer pair and mix its
output to both channels. That way, you pick up a good balance, and you
hear an accurate stereo spread.
The spaced-pair method tends to make off-center images unfocused
or hard to localize. Why? Spaced-pair recordings have time differences
between channels. Stereo images produced solely by time differences are
unfocused. You still hear the center instruments clearly in the center, but
off-center instruments are hard to pinpoint. Spaced-pair miking is a good
choice if you want the sonic images to be diffuse or blended, instead of
sharply focused.
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Practical Recording Techniques
Another flaw of spaced mics: If you mix both mics to mono, you
may get phase cancellations of various frequencies. This may or may not
be audible.
Spaced mics, however, give a “warm” sense of ambience, in which
the concert-hall reverb seems to surround the instruments and, sometimes, the listener. Here’s why: The two channels of recorded reverb are
incoherent; that is, they have random phase relationships. Incoherent
signals from stereo speakers sound diffuse and spacious. Because spaced
mics pick up reverb incoherently, it sounds diffuse and spacious. The simulated spaciousness caused by this phasiness is not necessarily realistic,
but it is pleasant to many listeners.
Another advantage of the spaced pair is that you can use omni mics.
An omni condenser mic has deeper bass than a uni condenser mic.
Near-Coincident Pair
In this method, you angle apart two directional mics, and space their
grilles a few inches apart horizontally (Figure 7.14). Even a few inches of
spacing increases the stereo spread and adds a sense of ambient warmth
or air to the recording. The greater the angle or spacing between mics,
the greater the stereo spread.
How does this method work? Angling directional mics produces
level differences between channels. Spacing mics produces time differences. The level differences and time differences combine to create the
stereo effect.
Figure 7.14
126
Near-coincident pair technique.
Microphone Technique Basics
7
If the angling or spacing is too great, you get exaggerated separation. If the angling or spacing is too small, you’ll hear a narrow stereo
spread.
A common near-coincident method is the ORTF system, which uses
two cardioids angled 110 degrees apart and spaced 7 inches (17 cm) horizontally. Usually this method gives accurate localization. That is, instruments at the sides of the orchestra are reproduced at or very near the
speakers, and instruments halfway to one side are reproduced about
halfway to one side.
Baffled Omni Pair
This method uses two omni mics, usually ear-spaced, and separated by
either a hard or soft baffle (Figure 7.15). To create stereo, it uses time differences at low frequencies and level differences at high frequencies. The
spacing between mics creates time differences. The baffle creates a sound
shadow (reduced high frequencies) at the mic farthest from the source.
Between the two channels, there are spectral differences—differences in
frequency response.
Some examples of baffled-omni pairs are the Schoeps or Neumann
sphere microphones, the Jecklin Disk, and the Crown SASS-P MKII stereo
microphone.
Figure 7.15
Baffled-omni technique.
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Practical Recording Techniques
Comparing the Four Techniques
1. Coincident pair:
• Uses two directional mics angled apart with grilles touching.
• Level differences between channels produce the stereo effect.
• Images are sharp.
• Stereo spread ranges from narrow to accurate.
• Signals are mono compatible.
2. Spaced pair:
• Uses two mics spaced several feet apart, aiming straight
ahead.
• Time differences between channels produce the stereo effect.
• Off-center images are diffuse.
• Stereo spread tends to be exaggerated unless a third center mic is
used, or unless spacing is under 2 to 3 feet.
• Provides a warm sense of ambience.
• Tends not to be mono compatible, but there are exceptions.
• Good low-frequency response if you use omni condensers.
3. Near-coincident pair:
• Uses two directional mics angled apart and spaced a few inches
apart horizontally.
• Level and time differences between channels produce the stereo
effect.
• Images are sharp.
• Stereo spread tends to be accurate. Provides a greater sense of air
than coincident methods.
• Tends not to be mono compatible.
Play CD track 22 to hear a comparison of the coincident, near-coincident
and spaced-pair techniques.
4. Baffled omni pair:
• Uses two omni mics, usually ear-spaced, with a baffle between
them.
• Level, time, and spectral differences produce the stereo effect.
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Microphone Technique Basics
•
•
•
•
•
•
7
Images are sharp.
Stereo spread tends to be accurate.
Good low-frequency response.
Good imaging with headphones.
Provides more air than coincident methods.
Tends not to be mono compatible, but there are exceptions.
Hardware
A handy device is a stereo mic adapter or stereo bar. It mounts two mics
on a single stand, and lets you adjust the angle and spacing. You might
prefer to use a stereo mic instead of two mics. It has two mic capsules in
a single housing for convenience.
How to Test Imaging
Here’s a way to check the stereo imaging of a mic technique.
1. Set up the stereo mic array in front of a stage.
2. Record yourself speaking from various locations on stage where the
instruments will be—center, half-right, far right, half-left, far left.
Announce your position.
3. Play back the recording over speakers.
You’ll hear how accurately the technique translated your positions,
and you’ll hear how sharp the images are.
We looked at several mic arrays to record in stereo. Each has its pros
and cons. Which method you choose depends on the sonic compromises
you’re willing to make.
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8
MICROPHONE TECHNIQUES
This chapter describes some ways to select and place mics for musical
instruments and vocals. These techniques are popular, but they’re just
suggested starting points. Feel free to experiment.
Before you mike an instrument, listen to it live in the studio, so you
know what sound you’re starting with. You might want to duplicate that
sound through your monitor speakers.
Electric Guitar
Let’s start by looking at the chain of guitar, effects, amplifier, and speaker.
At each point in the chain where you record, you’ll get a different sound
(Figure 8.1).
1. The electric guitar puts out an electrical signal that sounds clean and
clear.
2. This signal might go through some effects boxes, such as distortion,
wah wah, compression, chorus, or stereo effects.
3. Then the signal goes through a guitar amp, which boosts the signal
and adds distortion. At the amplifier output (preamp out or external speaker jack), the sound is very bright and edgy.
4. The distorted amp signal is played by the speaker in the amp.
Because the speaker rolls off above 4 kHz, it takes the edge off the
distortion and makes it more pleasant.
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Practical Recording Techniques
RECORD
HERE
RECORD
HERE
RECORD
HERE
Figure 8.1
Three places to record the electric guitar.
You can record the electric guitar in many ways (Figure 8.1):
•
•
•
•
With a mic in front of the guitar amp
With a direct box
Both miked and direct
Through a signal processor or stomp box
The song you’re recording will tell you what method it wants. Just
mike the amp when you want a rough, raw sound with tube distortion
and speaker coloration. Rock ‘n’ roll or heavy metal usually sounds best
with a miked amp. If you record through a direct box, the sound is clean
and clear, with crisp highs and deep lows. That might work for quiet
jazz or R&B. Use whatever sounds right for the particular song you’re
recording.
First, try to kill any hum you hear from the guitar amp. Turn up the
guitar’s volume and treble controls so that the guitar signal overrides
hum and noise picked up by the guitar cable. Ask the guitarist to move
around, or rotate, to find a spot in the room where hum disappears. Flip
the polarity switch on the amp to the lowest-hum position. To remove
buzzes between guitar notes, try a noise gate, or ask the player to keep
his or her hands on the strings.
Miking the Amp
Small practice amplifiers tend to be better for recording than large, noisy
stage amps. If you use a small one, place it on a chair to avoid picking
up sound reflections from the floor (unless you like that effect).
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8
A common mic for the guitar amp is a cardioid dynamic type with
a “presence peak” in its frequency response (a boost around 5 kHz). The
cardioid pattern reduces leakage (off-mic sounds from other instruments). The dynamic type handles loud sounds without distorting, and
the presence peak adds “bite.” Of course, you can use any mic that
sounds good to you.
As a starting point, try miking the amp about an inch from the grille
near a speaker cone, slightly off-center—where the cone meets the dome.
The closer you mike the amp, the bassier the tone. The farther offcenter the mic is, the duller the tone. Often, distant miking sounds great
when you overdub a lead guitar solo played through a stack of speakers
in a live room. Try a boundary mic on the floor or on the wall, several
feet away.
Recording Direct
Now let’s look at recording direct (also known as direct injection or DI).
The electric guitar produces an electrical signal that you can plug into
your mixer. You bypass the mic and guitar amp, so the sound is clean
and clear. Just remember that amp distortion is desirable in some songs.
Mixer mic inputs tend to have an impedance (Z) around 1500 ohms.
But a guitar pickup is several thousand ohms. So if you plug a high-Z
electric guitar directly into a mic input, the input will load down the
pickup and give a thin or dull sound.
To get around this loading problem, use a direct box between the
guitar and your mixer (Figure 8.2). The DI box has a high-Z input and
low-Z output, thanks to a built-in transformer or circuit. Some mixers
INSTRUMENT
AMP
Figure 8.2
GND
LIFT
MIC-LEVEL
OUTPUT
Typical direct box.
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Practical Recording Techniques
have a high-Z input jack built in, so you can plug the electric guitar or
bass directly into this jack.
The direct box should have a ground-lift switch to prevent ground
loops and hum. Set it to the position where you monitor the least hum.
You might try a mix of direct sound and miked sound. Play track 23 on
the enclosed CD to hear demonstrations of electric-guitar recording methods.
Electric Guitar Effects
If you want to record the guitarist’s effects, connect the output of the
effects boxes into the direct-box input. Many players have a rack of signal
processors that creates their unique sound, and they just give you their
direct feed. Be open to their suggestions, and be diplomatic about changing the sound. If they are studio players, they often have a better handle
on effects than you might as the engineer.
You might want a “fat” or spacious lead-guitar sound. Here are some
ways to get it:
• Send the guitar signal through a digital delay set to 20 to 30 msec.
Pan guitar left, delay right. Adjust levels for nearly equal loudness
from each speaker. (Watch out for phase cancellations in mono.)
• Send the guitar signal through a pitch-shifter, set for about 10 cents
of pitch bending. Pan guitar left, pitch-shifted guitar right. (A cent
is 1/100 of an equal-temperament semitone. There are 100 cents in
a half-tone or semitone interval of pitch).
• Record two guitarists playing identical parts, and pan them left and
right. This works great for rhythm-guitar parts in heavy metal.
• Double the guitar. Have the player re-record the same part on an
unused track while listening to the original part. Pan the original
part left and pan the new part right.
• Add stereo reverb or stereo chorus.
Some guitar processors add many effects to an electric guitar, such
as distortion, EQ, chorus, and compression. An example is the Line 6 Pod.
You simply plug the electric guitar into the processor, adjust it for the
desired sound, and record the signal direct. You wind up with a fully produced sound with a minimum of effort.
Re-amping is a technique that lets you work on the amp’s sound
during mixdown rather than during recording. Record the guitar direct,
then feed that track’s signal into a guitar processor or miked guitar amp
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8
during mixdown. Use a low- to high-Z transformer between the track
output and the processor or amp input. Record the processor or amp on
an open track. In a digital audio workstation (DAW), you can start with
a track of a direct-recorded guitar, then insert a guitar-amp modeling
plug-in.
Electric Bass
BWAM, dik diddy bum. Do your bass tracks sound that clear? Or are they
more muddy, like, “Bwuh, dip dubba duh”? Here’s how to record the
electric bass so it’s clean and easy to hear in a mix.
As always, first you work on the sound of the instrument itself. Put
on new strings if the old ones sound dull. Adjust the pickup screws (if
any) for equal output from each string. Also adjust the intonation and
tuning.
Usually, you record the electric bass direct for the cleanest possible
sound. A direct pickup gives deeper lows than a miked amp, but the amp
gives more midrange punch. You might want to mix the direct and miked
sound. Use a condenser or dynamic mic with a good low-frequency
response, placed 1 to 6 inches from the speaker.
When mixing a direct signal and a mic signal, make sure they are
in-phase with each other. To do this, set them to equal levels and reverse
the polarity of the direct signal or the mic signal. The polarity that gives
the most bass is correct.
Have the musician play some scales to see if any notes are louder
than the rest. You might set a parametric equalizer to soften these notes,
or use a compressor.
The bass guitar should be fairly constant in level (a dynamic range
of about 6 dB) to be audible throughout the song, and to avoid clipping
the recording on loud peaks. To do this, run the bass guitar through a
compressor. Set the compression ratio to about 4 : 1; set the attack time
fairly slow (8 to 20 msec) to preserve the attack transient; and set the
release time fairly fast (1/4 to 1/2 second). If the release time is too fast,
you get harmonic distortion.
EQ can make the bass guitar clearer. Try cutting around 60 to 80 Hz,
or at 400 Hz. A boost at 2 to 2.5 kHz adds edge or slap, and a boost at 700
to 900 Hz adds “growl” and harmonic clarity. If you boost the lows
around 100 Hz, try boosting at a lower frequency in the kick drum’s EQ
to keep their sounds distinct. A fretless bass will probably need different
EQ or less EQ than a fretted bass.
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Practical Recording Techniques
Here are some ways to make the bass sound clean and well defined:
• Record the bass direct.
• Use no reverb or echo on the bass.
• Have the bass player turn down the bass amp in the studio, just loud
enough to play adequately. This reduces muddy-sounding bass
leakage into other mics.
• Better yet, don’t use the amp. Instead, have the musicians monitor
the bass (and each other) with headphones.
• Have the bass player try new strings or a different guitar. Some
guitars are better for recording than others. Use roundwound strings
for a bright tone or flatwounds for a rounder tone.
• Ask the bass player to use the treble pickup near the bridge.
• Be sure to record the bass with enough edge or harmonics so the
bass will be audible on small, cheap speakers.
• Try a bass-guitar signal processor such as the Bass Rockman (discontinued), Zoom, or DigiTech.
If the bass part is full and sustained, it’s probably best to go
for a mellow sound without much pluck. Let the kick drum define the
rhythmic pattern. But if both the bass and kick are rhythmic and work
independently, then you should hear the plucks. Listen to the song first,
then get a bass sound appropriate for the music. A sharp, twangy timbre
is not always right for a ballad; a full, round tone will get lost in a fusion
piece.
Often, a musician plays bass lines on a synth or sound module. The
module is triggered from a keyboard, a sequencer, or a bass guitar
plugged into a pitch-to-MIDI converter. Connect the module output to
your mixer line in.
Two effects boxes for the electric bass are the octave box and the bass
chorus. The octave box takes the bass signal and drops it an octave in
pitch. That is, it divides the bass signal’s fundamental frequency in two.
You put 82 Hz in; you get 41 Hz out. This gives an extra deep, growly
sound. So does a 5-string bass.
A bass chorus gives a wavy, shimmering effect. Like a conventional
chorus box, it detunes the signal and combines the detuned signal with
the direct signal. Also, it removes the lowest frequencies from the detuned
signal, so that the chorus effect doesn’t thin out the sound.
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Microphone Techniques
8
Synthesizer, Drum Machine, and Electric Piano
For the most clarity, you usually DI a synth, MIDI sound module, drum
machine, or electric piano. Set the volume on the instrument about threequarters up to get a strong signal. Try to get the sound you want from
patch settings rather than EQ.
Plug the instrument into a phone jack input on your mixer, or use a
direct box. If you connect to a phone jack and hear hum, you probably
have a ground loop. Here are some fixes:
• Power your mixer and the instrument from the same outlet strip. If
necessary, use a thick extension cord between the outlet strip and
the instrument.
• Use a direct box instead of a guitar cord, and set the ground-lift
switch to the position where you monitor the least hum.
• To reduce hum from a low-cost synth, use battery power instead of
an AC adapter.
A synth can sound dry and sterile. To get a livelier, funkier sound,
you might run the synth signal into a power amp and speakers, and mike
the speakers a few feet away.
If the keyboard player has several keyboards plugged into a keyboard mixer, you may want to record a premixed signal from that mixer’s
output. Record both outputs of stereo keyboards.
Leslie Organ Speaker
This glorious device has a rotating dual-horn on top for highs and a
woofer on the bottom for lows. Only one horn of the two makes sound;
the other is for weight balance. The swirling, grungy sound comes from
the phasiness and Doppler effect of the rotating horn, and from the distorted tube electronics that drive the speaker. Here are a few ways to
record it (Figure 8.3):
• In mono: Mike the top and bottom separately, 3 inches to 1 foot
away. Aim the mics into the louvers. In the top mic’s signal, roll off
the lows below 150 Hz.
• In stereo: Record the rotating horn in stereo with a mic on either side.
Problem: The horn will sound like it’s rotating twice as fast, because
the mics will pick up the horn twice per rotation.
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Practical Recording Techniques
Figure 8.3
Miking a Leslie organ speaker.
• In stereo: Record the top horn with a stereo mic or a pair of mics out
front. Put a mic with a good low end on the bottom speaker, and
pan it to center.
When you record the Leslie, watch out for wind noise from the rotating horn and buzz from the motor. Mike farther away if you monitor
these noises.
Rather than recording an actual Leslie speaker and Hammond B3
organ, you might prefer to use a software emulation of those instruments.
CDs and soft synths are available that simulate great sound with samples,
which can be triggered by MIDI sequencers or MIDI controllers (covered
in Chapter 16 on MIDI).
Drum Set
The first step is to make the drums sound good live in the studio. If the
set sounds poor, you’ll have a hard time making it sound great in the
control room! You might put the drum set on a riser 1–1/2 feet high to
reduce bass leakage and to provide better eye contact between the
drummer and the rest of the band. To reduce drum leakage into other
mics, you could surround the set with goboes—padded thick-wood
panels about 4 feet tall. For more isolation, place the set in a drum booth,
a small padded room with windows. It’s also common to overdub the set
in a live room.
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Microphone Techniques
8
Tuning
One secret to creating a good drum sound lies in careful tuning. It’s easier
to record a killer sound if you tune the set to sound right in the studio
before miking it.
First let’s consider drum heads. Plain heads have the most ring or
sustain, while heads with sound dots or hydraulic heads dampen the
ring. Thin heads are best for recording because they have crisp attack and
long sustain. Old heads become dull, so use new heads.
When you tune the toms, first take off the heads and remove the
damping mechanism, which can rattle. Put just the top head on and handtighten the lugs. Then, using a drum key, tighten opposite pairs of lugs
one at a time, one full turn. After you tighten all the lugs, repeat the
process, tightening one-half turn. Then press on the head to stretch it.
Continue tightening a half-turn at a time until you reach the pitch you
want. You’ll get the most pleasing tone when the heads are tuned within
the range of the shell resonance.
To reduce ugly overtones, try to keep the tension the same around
the head. While touching the center of the head, tap with a drumstick on
the head near each lug. Adjust tension for equal pitch around the drum.
If you want a downward pitch bend after the head is struck, loosen
one lug.
Keep the bottom head off the drum for the most projection and the
broadest range of tuning. In this case, pack the bottom lugs with felt to
prevent rattles. But you may want to add the bottom head for extra
control of the sound. Projection is best if the bottom head is tighter than
the top head—say, tuned a fourth above the top head. There will be a
muted attack, an “open” tone, and some note bending. If you tune the
bottom head looser than the top, the tone will be more “closed,” with
good attack.
With the kick drum (bass drum), a loose head gives lots of slap and
attack, and almost no tone. The opposite is true for a tight head. Tune the
head to complement the style of music. For more attack or click, use a
hard beater.
Tune the snare drum with the snares off. A loose batter head or top
head gives a deep, fat sound. A tight batter head sounds bright and crisp.
With the snare head or bottom head loose, the tone is deep with little
snare buzz, while a tight snare head yields a crisp snare response. Set the
snare tension just to the point where the snare wires begin to “choke” the
sound, then back off a little.
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Practical Recording Techniques
Damping and Noise Control
Usually the heads should ring without any damping. But if the toms or
snare drum rings too much, put some plastic damping rings on them. Or
tape some gauze pads, tissues, or folded handkerchiefs to the edge of the
heads. Put masking tape on three sides of the pad so that the untaped
edge is free to vibrate and dampen the head motion. Don’t overdo the
damping, or the drum set will sound like cardboard boxes.
Oil the kick drum pedal to prevent squeaks. Tape rattling hardware
in place.
Sometimes a snare drum buzzes in sympathetic vibration with a
bass-guitar passage or a tom-tom fill. Try to control the buzz by wedging
a thick cotton wad between the snares and the drum stand. Or tune the
snare to a different pitch than the toms.
Drum Miking
Now you’re ready to mike the set. For a tight sound, place a mic near
each drum head. For a more open, airy sound, use fewer mics or mix in
some room mics placed several feet away. Typical room mics are omni
condensers or boundary mics. Figure 8.4 shows typical mic placements
for a rock drum set. Let’s look at each part of the kit.
Snare
The most popular type of mic for the snare is a cardioid dynamic with a
presence peak. The cardioid pattern reduces leakage; its proximity effect
boosts the bass for a fatter sound. The presence peak adds attack. You
might prefer a cardioid condenser for its sharp transient response.
Bring the mic in from the front of the set on a boom. Place the mic
even with the rim, 1 or 2 inches above the head (Figure 8.5). Angle the
mic down to aim where the drummer hits, or attach a mini condenser
mic to the side of the snare drum so it “looks at” the top head over
the rim.
Some engineers mike both the top and bottom heads of the snare
drum, with the microphones in opposite polarity. A mic under the snare
drum gives a zippy sound; a mic over the snare drum gives a fuller
sound. You might prefer to use just a top mic, and move it around until
it picks up both the top head and snares. The sound is full with the mic
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Microphone Techniques
OVERHEAD
MIC
ALTERNATE MIKING
WITH A STEREO PAIR
8
OVERHEAD
MIC
RACK TOM MICS
SNARE
MIC
FLOOR TOM
MIC
KICK
MIC
Figure 8.4
Typical mic placements for a rock drum set.
Figure 8.5
Snare-drum miking.
near the top head, and thins out and becomes brighter as you move the
mic toward the rim and down the side of the drum.
Whenever the hi-hat closes, it makes a puff of air that can “pop” the
snare-drum mic. Place the snare mic so the air puff doesn’t hit it. To
prevent hi-hat leakage into the snare mic:
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Practical Recording Techniques
• Mike the snare closely.
• Bring the snare boom in under the hi-hat, and aim the snare mic
away from the hi-hat.
• Use a piece of foam or pillow to block sound from the hi-hat.
• Use a de-esser on the snare.
• Overdub the hi-hat.
Hi-Hat
Try a cardioid condenser mic about 6 inches over the cymbal edge that’s
farthest from the drummer (Figure 8.6). To avoid the air puff just mentioned, don’t mike the hi-hat off its side; mike it from above aiming down.
This also reduces snare leakage. You may not need a hi-hat microphone,
especially if you use room mics. Usually the overhead mics pick up
enough hi-hat.
Tom-Toms
You can mike the toms individually, or put a mic between each pair of
toms. The first option sounds more bassy. Place a cardioid dynamic about
Figure 8.6
142
Hi-hat miking.
Microphone Techniques
Figure 8.7
8
Tom-tom miking.
1 inch over the drumhead and 1 inch in from the rim, angled down about
45 degrees toward the head (Figure 8.7). Again, the cardioid’s proximity
effect gives a full sound. Another way is to clip mini condenser mics to
the toms, peeking over the top rim of each drum.
If the tom mics pick up too much of the cymbals, aim the “dead”
rear of the tom mics at the cymbals. If you use a supercardioid or hypercardioid mic, aim the null of best rejection at the cymbals.
Another way to reduce cymbal leakage is to remove the bottom
heads from the toms and mike them inside a few inches from the head,
off-center. This also keeps the mics out of the drummer’s way. The sound
picked up inside the tom-tom has less attack and more tone than the
sound picked up outside.
Kick Drum
Place a blanket or folded towel inside the drum, pressing against the
beater head to dampen the vibration and tighten the beat. The blanket
shortens the decay portion of the kick-drum envelope. To emphasize the
attack, use a wood or plastic beater—not felt—and tune the drum low.
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Practical Recording Techniques
A popular mic for kick drum is a large-diameter, cardioid dynamic
type with an extended low-frequency response. Some mics are designed
specifically for the kick drum, such as the AKG D112, Audio-Technica AT
AE2500, Electro-Voice N/D868, and Shure Beta 52A.
For starters, place the kick mic inside on a boom, a few inches from
where the beater hits (Figure 8.8). Mic placement close to the beater picks
up a hard beater sound; off-center placement picks up more skin tone,
and farther away picks up a boomier shell sound.
Other miking tips: Hang a mini omni condenser mic inside near the
beater, or place an omni condenser a few inches from the beater. These
mics respond to very deep frequencies and have sharp transient response,
which helps the attack.
How should the recorded kick drum sound? Well, they don’t call it
kick drum for nothing. THUNK! You should hear a powerful low-end
thump plus an attack transient.
Kick drum often needs a fair amount of EQ to sound good. Typically
you cut several decibels around 400 Hz to remove the “papery” sound,
boost 60 to 80 Hz if the kick sounds thin, and boost around 3 to 5 kHz to
add click or snap. Don’t overdo the high-frequency boost; usually you
don’t want too much “point” on the kick sound.
Cymbals
To capture all the crisp “ping” of the cymbals, a good mic choice is a cardioid condenser with an extended high-frequency response, flat or rising.
Place the overhead mics about 2 to 3 feet above the cymbal edges; closer
miking picks up a low-frequency ring. The cymbal edges radiate the most
highs. Place the cymbal mics to pick up all the cymbals equally. If your
recording will be heard in mono, or for sharper imaging, you might want
to mount the mic grilles together and angle the mics apart (Figure 8.4).
Figure 8.8
144
Kick-drum miking.
Microphone Techniques
8
Or use a stereo mic. Also try a near-coincident pair aimed at the high-hat
and floor tom.
Recorded cymbals should sound crisp and smooth, not muffled or
harsh.
Room Mics
Besides the close-up drum mics, you might want to use a distant pair of
room mics when you record drum overdubs. Place the mics about 10 or
20 feet from the set to pick up room reverb. When mixed with the closeup mics, the room mics give an open, airy sound to the drums. Popular
room mics are omni condensers or boundary mics taped to the controlroom window. You might compress the room mics for special effect. If
you don’t have enough tracks for room microphones, try raising the overhead mics.
Boundary Mic Techniques
Boundary mics let you pick up the set in unusual ways. You can strap
one on the drummer’s chest to pick up the set as the drummer hears it.
Tape them to hard-surfaced goboes surrounding the drummer. Put them
on the floor under the toms and near the kick drum, or hang a pair over
the cymbals. Try a supercardioid boundary mic in the kick drum.
Recording with Two to Four Mics
Sometimes you can mike the set simply. Place a stereo mic (or two mics)
overhead and put another mic in the kick. If necessary, add a snare-drum
mic (Figure 8.9). This method works well for acoustic jazz, and often for
rock. If you want the toms to sound fuller, boost the lows in the overhead
mics. Also try two mics about 18 inches apart angled down at the set from
just over the drummer’s head.
Another setup is shown in Figure 8.10. It uses only one mini omni
condenser mic and one kick-drum mic. This method sometimes works
well on small drum sets. Clip a mini omni condenser mic to the snaredrum rim about 4 inches above the rim, in the center of the set, aiming
at the hi-hat. Also mike the kick drum.
The mini mic will pick up the snare, hi-hat, and toms all around it,
and will pick up the cymbals from underneath. Move the mic closer or
farther from the toms, and raise or lower the cymbals, until you hear a
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Practical Recording Techniques
OVERHEAD
MIC
ALTERNATE MIKING
WITH A STEREO PAIR
OVERHEAD
MIC
SNARE
MIC
KICK
MIC
Figure 8.9
Miking a drum set with four mics.
MINI OMNI
MIC
KICK
MIC
Figure 8.10
146
Miking a drum set with a mini omni mic.
Microphone Techniques
8
pleasing balance. Add a little bass and treble. You’ll be surprised at the
good sound and even coverage you can get with this simple setup.
Want a stereo effect? Mount one mic 4 inches above the snare drum
rim between the hi hat, snare drum, and rack tom. Adjust position for
best balance. Mount another mic four inches above the floor-tom rim, on
the side farthest from the drummer (Figure 8.11). Pan the mini mics left
and right.
Track 24 on the enclosed CD demonstrates several methods of miking a
drum set.
Drum Recording Tips
After you set up all the mics, ask the drummer to play. Listen for rattles
and leakage by soloing each microphone. Try not to spend much time
getting a sound; otherwise you waste the other musicians’ time and wear
out the drummer.
To keep the drum sound tight, turn off mics not in use in a particular tune, use a noise gate on each drum mic, or overdub the drums.
One effect for the snare drum is gated reverb. It’s a short splash of
bright-sounding reverberation, which is rapidly cut off by a noise gate or
expander. Many effects units have a gated-reverb program.
Another trick is recording “hot.” Using an analog multitrack (or its
plug-in equivalent), record the drums at a high level so they distort just
a little. It’s also common to compress the kick.
MINI OMNI
MIC
MINI OMNI
MIC
KICK
MIC
Figure 8.11
Miking a drum set with two mini omni mics.
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Practical Recording Techniques
A drummer might use drum pads, or drum triggers, fed into a sound
module. Record directly off the module. You might want to mike the
cymbals anyway for best sound.
If you’re recording a drum machine and it sounds too mechanical,
add some real drums. The machine can play a steady background while
the drummer plays fills.
When miking drums on stage for PA, you don’t need a forest of
unsightly mic stands and booms. Instead, you can use short mic holders
that clip onto drum rims and cymbal stands, or use mini condenser mics.
In a typical rock mix, the drums either are the loudest element, or
are slightly quieter than the lead vocal. The kick drum is almost as loud
as the snare. If you don’t want a wimpy mix, keep those drums up front!
Try these EQ settings to enhance the recorded sound of the drums:
• Snare and rack toms: Fat at 200Hz, crack at 5kHz. Cut around 400Hz
on toms for clarity. If the sound is too tubby, cut around 200Hz.
• Floor toms: Fullness at 80 to 100 Hz.
• Cymbals: Sizzle at 10 kHz or higher. Roll off the lows below 500 Hz
to reduce low-frequency leakage.
• Kick drum: Boost at 3 to 5 kHz for click. Filter out highs above 9 kHz
to reduce leakage from cymbals. To remove the “cardboard” sound,
cut at 300 to 600 Hz.
A typical track assignment for drums might be
1. Kick
2. Snare
3 & 4. Toms in stereo
5 & 6. Overheads in stereo
Try these tricks to come up with unusual drum sounds:
• Record with a cheap dynamic or crystal mic, maybe in a can.
• Run the drums through extreme processing: compression, gating,
distortion, pitch shifting, tremolo, and so on.
• Substitute other objects for drums, cymbals, drumsticks, and
brushes.
• Move a mic around a cymbal or drumhead while recording it.
• Put the drums in a reverberant room or hallway.
• Try the preverb effect described in Chapter 10.
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8
Instead of recording an acoustic drum set, you might use an electronic drum set or CDs of drum samples. Copy the samples into a sampler
or sampling software, then trigger them with a MIDI sequencer or MIDI
controller.
Percussion
Let’s move on to percussion, such as the cowbell, triangle, tambourine,
or bell tree. A good mic for metal percussion is a condenser type because
it has sharp transient response. Mike at least 1 foot away so the mic
doesn’t distort.
You can pick up congas, bongos, and timbales with a single mic
between the pair, a few inches over the top rim, aimed at the heads. Or
put a mic on each drum. It often helps to mike these drums top and
bottom, with the bottom mic in opposite polarity. A cardioid dynamic
with a presence peak gives a full sound with a clear attack.
For xylophones and vibraphones, place two cardioid mics 1–1/2 feet
above the instrument, aiming down. Cross the mics 135 degrees apart or
place them about 2 feet apart. You’ll get a balanced pickup of the whole
instrument.
Acoustic Guitar
The acoustic guitar has a delicate timbre that you can capture through
careful mic selection and placement. First prepare the acoustic guitar for
recording. To reduce finger squeaks, try commercial string lubricant, a
household cleaner/waxer, talcum powder on fingers, or smooth-wound
strings. Ask the guitarist to play louder; this increases the “music-tosqueak” ratio!
Replace old strings with new ones a few days before the session.
Experiment with different kinds of guitars, picks, and finger picking to
get a sound that’s right for the song.
For acoustic guitar, a popular mic is a condenser with a smooth,
extended frequency response from 80 Hz up. This kind of mic has a
clear, detailed sound. You can hear each string being plucked in a
strummed chord. Usually the sound picked up is as crisp as the real
thing.
Now let’s look at some mic positions. To record a classical guitar solo
in a recital hall, mike about 3 to 6 feet away to pick up room reverb. Try
a stereo pair (Figure 8.12A), such as XY, ORTF, MS, or spaced pair
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Practical Recording Techniques
NATURAL
STEREO MIKING
A CLASSICAL SOLO
B
A
STEREO
D
F
Figure 8.12
BASSY BUT
GOOD ISOLATION
E
C
MINI MIC
Some mic techniques for acoustic guitar.
(described in Chapter 7). If you record a classical guitar solo in a dead
studio, mike about 1.5 to 2 feet away and add artificial reverb.
When you record pop, folk, or rock music, try a spot about 6 to 12
inches from where the fingerboard joins the guitar body—at about the
12th fret (Figure 8.12B). That’s a good starting point for capturing the
acoustic guitar accurately. Still, you need to experiment and use your
ears. Close to the bridge, the sound is woody and mellow.
In general, close miking gives more isolation, but tends to sound
harsh and aggressive. Distant miking lets the instrument “breathe”; you
hear a gentler, more open sound.
Another spot to try: Tape a mini omni mic onto the body near the
bottom of the sound hole, and roll off the excess bass. This spot gives
good isolation (Figure 8.12C).
The guitar will sound more real if you record in stereo. Try one mic
near the bridge, and another near the 12th fret (Figures 8.12D and E). Pan
part-way left right. Another way to record stereo is with an XY pair of
cardioid mics about 6 inches from the end of the fingerboard, mixed with
a 3-foot-spaced pair of omni mics about 3 feet away.
Is feedback or leakage a problem? Mike close to the sound hole
(Figure 8.12F). The tone there is very bassy, so turn down the lowfrequency EQ on your mixer until the sound is natural. Also cut a few
decibels around 3 kHz to reduce harshness.
You get the most isolation with a contact pickup. It attaches to the
guitar, usually under the bridge. The sound of a pickup is something like
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Microphone Techniques
8
an electric guitar. You can mix a mic with a pickup to add air and string
noise to the sound of the pickup. That way, you get good isolation and
good tone quality.
Singer/Guitarist
Normally you overdub the guitar and vocal separately. But if you have
to record both at once, the vocal might sound filtered or hollow because
of phase cancellations between the vocal mic and guitar mic. This can
happen whenever two mics pick up the same source at approximately
equal levels, at different distances, and both mixed to the same channel.
Try one of these methods to solve the problem:
• Angle the vocal mic up and angle the guitar mic down to isolate the
two sources. Follow the 3 : 1 rule described in Chapter 7.
• Use a pickup or mini mic on the guitar.
• Delay the vocal mic about 1 msec. This keeps the two mic signals in
phase, preventing phase cancellations. Some multitrack recorders
have a track-delay feature for this purpose.
• Use a coincident pair of figure-eight (bidirectional) mics crossed at
90 degrees. Aim the front of one mic at the voice; aim the front of
the other mic at the guitar.
• Use a stereo mic or stereo pair about 1 foot out front; raise or lower
the mics to adjust the voice/guitar balance.
Grand Piano
This magnificent instrument is a challenge to record well. First have the
piano tuned, and oil the pedals to reduce squeaks. You can prevent
thumps by stuffing some foam or cloth under the pedal mechanism.
For a classical-music solo, record in a reverberant room such as a
recital hall or concert hall. Reverb is part of the sound. Set the piano lid
on the long stick. Use condenser mics with a flat response. Place a stereo
mic, or a stereo pair of cardioid mics, about 7 feet away and 7 feet high,
up to 9 feet away and 9 feet high (Figure 8.13). Move the mics closer to
reduce reverb, farther to increase it. When using a pair of omni mics, place
them 1.3 to 2 feet apart, 3 to 6.5 feet from the piano, and 4 to 5 feet high
(Figure 8.14). You might need to mix in a pair of hall mics: Try cardioids
aiming away from the piano about 25 feet away.
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Practical Recording Techniques
Figure 8.13
mics).
Suggested grand-piano miking for classical music (using cardioid
Omni mics
3 ft. - 6.5 ft.
4 ft. - 5 ft.
Omni mics
1.3 ft. - 2 ft.
Figure 8.14 Suggested grand-piano miking for classical music (using omnidirectional mics).
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Microphone Techniques
8
When recording a piano concerto, give the piano a spot mic about 3
feet away. Put the mic in a shock mount.
Pop music demands close miking. Close mics pick up less room
acoustics and leakage, and give a clear sound that cuts through the mix.
Try not to mike the strings closer than 8 inches, or else you’ll emphasize
the strings closest to the mics. You want equal coverage of all the notes
the pianist plays.
One popular method uses two spaced mics inside the piano. Use
omni or cardioid condensers, ideally in shock mounts. Put the lid on the
long stick. If you can, remove the lid to reduce boominess. Center one
mic over the treble strings and one over the bass strings. Typically, both
mics are 8 to 12 inches over the strings and 8 inches horizontally from
the hammers (Figure 8.15, top, bass and treble mics). Aim the mics
straight down or angle them to aim at the hammers. Pan the mics partly
BASS MIC
BASS MIC
STEREO PAIR
(ALTERNATIVE)
TREBLE MIC
TREBLE MIC
HAMMERS
MICS angled or
straight down
HAMMERS
8 TO 12 IN.
8 TO 12 IN.
BASS MIC
TREBLE MIC
Boundary mics gaffer-taped
to underside of raised lid
Figure 8.15
Suggested grand-piano miking for popular music.
153
Practical Recording Techniques
left and right for stereo. As an alternative, try two ear-spaced omni condensers or an ORTF pair about 12 to 18 inches above the strings. Track 25
on the enclosed CD demonstrates some mic techniques for grand piano.
The spaced mics might have phase cancellations when mixed to
mono, so you might want to try coincident miking (Figure 8.15, top,
stereo pair). Boom-mount a stereo mic, or an XY pair of cardioids crossed
at 120 degrees. Miking close to the hammers sounds percussive; toward
the tail has more tone.
For more clarity and attack, boost EQ around 10 kHz or use a mic
with a rising high-frequency response.
Boundary mics work well, too. If you want to pick up the piano
in mono, tape a boundary mic to the underside of the raised lid, in
the center of the strings, near the hammers. Use two for stereo over
the bass and treble strings. Put the bass mic near the tail of the piano to
equalize the mic distances to the hammers (Figure 8.15, bottom). If
leakage is a problem, close the lid and cut EQ around 250 Hz to reduce
boominess.
If your studio lacks a piano, consider using a software emulation of
a piano. Some programs provide high-quality samples of piano notes that
can be played with a sequencer or a MIDI controller. Examples: Steinberg
Grand VST 2.0 ($199 at www.steinberg.net) and Maxim Digital Audio
Piano (freeware at www.mda-vst.com).
Upright Piano
Here are some ways to mike an upright piano (Figure 8.16):
(A) Remove the panel in front of the piano to expose the strings over
the keyboard. Place one mic near the bass strings and one near the treble
strings about 8 inches away. Record in stereo and pan the signals left and
right for the desired piano width. If you can spare only one mic for the
piano, just cover the treble strings.
(B) Remove the top lid and upper panel. Put a stereo pair of
mics about 1 foot in front and 1 foot over the top. If the piano is against
a wall, angle the piano about 17 degrees from the wall to reduce tubby
resonances.
(C) Aim the soundboard into the room. Mike the bass and treble
sides of the soundboard a few inches away. In this spot, the mics pick up
less pedal thumps and other noises. Try cardioid dynamic mics with a
presence peak.
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Microphone Techniques
Figure 8.16
8
Some mic techniques for upright piano.
Acoustic Bass
The acoustic bass (string bass, double bass) puts out frequencies as low
as 41 Hz, so use a mic with an extended low-frequency response. As
always, closer miking improves isolation, while distant miking tends to
sound more natural. Try these techniques (Figure 8.17):
• 4 to 18 inches in front of the bridge, on the side toward the G string
(top string), a few inches above the bridge.
• For more fullness, move the mic toward the f-hole. Move the mic
upward for more definition.
• 18 to 24 inches above the treble f-hole.
• Mix a pickup with a mic, or use a pickup alone and EQ it to sound
good.
If you need more isolation, place a cardioid dynamic mic near the
treble f-hole and roll off the excess bass on your mixer. Or try a cardioid
dynamic mic 6 inches from the strings, 4 inches below the bridge, pointing at the base of the bridge (Figure 8.17). Mix with a pickup.
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Practical Recording Techniques
ACOUSTIC BASS
SIDE VIEW
18-24 IN. ABOVE
TREBLE F-HOLE
MIC OUT FRONT
4-18 IN.
MIC IN FOAM
BEHIND BRIDGE
Figure 8.17
CARDIOID DYNAMIC
Some mic techniques for the acoustic bass.
Here are some methods that isolate the bass and let the player move
around. They work well for PA:
• Wrap a mini omni condenser mic in foam rubber (or in a foam windscreen) and mount it in the bridge aiming up (Figure 8.17).
• Tape a mini omni mic to the bridge.
• Wrap a regular cardioid mic in foam padding (except the front grille)
and squeeze it behind the bridge (Figure 8.17) or tailpiece.
• For best isolation, try a direct feed from a pickup. This method adds
clarity and deep bass, but probably will need some EQ. You might
mix the pickup with a microphone.
Banjo
Try a flat-response mic about 1 foot away (Figure 8.18). If you need more
isolation, mike closer and roll off some bass. The banjo sounds pleasantly
mellow when miked toward the edge of the head, near the resonator
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Microphone Techniques
8
BANJO
MINI OMNI
ON BRIDGE
MIC 1 FOOT
OUT FRONT
MINI OMNI
ON HEAD
Figure 8.18
MIC NEAR
EDGE
Four methods for miking a banjo.
holes (if the banjo has them). Cloth stuffed inside will reduce feedback in
PA situations.
For the most isolation, tape a mini omni condenser mic to the head
about 1 inch in from the bottom edge, or on the tailpiece, or on the bridge.
You can wedge a pickup between the strings below the bridge and the
banjo head. Put the pickup flat against the head surface.
Mandolin, Dobro, Bouzouki, and Lap Dulcimer
Mike these about 8 to 12 inches away with a condenser mic. If you need
more lows and more isolation, mike close to an f-hole. You can tape a
mini omni condenser mic near an f-hole and tweak EQ for the best sound.
Hammered Dulcimer
Place a flat-response condenser mic about 2 feet over the center of the
soundboard (Figure 8.19A). On stage, place a cardioid dynamic or condenser 6 to 12 inches over the middle of the top end (Figure 8.19B). For
the best gain-before-feedback in a PA system, mix in a mini omni condenser mic (or a cardioid with bass rolloff) very near the sound hole
(Figure 8.19C).
Fiddle (Violin)
Listen to the fiddle itself to make sure it sounds good. Correct any instrument problems before miking.
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Practical Recording Techniques
Figure 8.19
Some mic techniques for hammered dulcimer.
OVERHEAD
FOR SINGING
FIDDLER
SIDE
Figure 8.20
Three fiddle-miking methods.
First try a flat-response condenser mic (omni or cardioid) about 2
feet over the bridge. This distant miking gives an airy, silky sound. Close
miking (about 1 foot, Figure 8.20) sounds more aggressive, which is
desirable in old-time or bluegrass music. Aim the mic toward the f-holes
for warmth or toward the fingerboard for clarity. Try miking the fiddle
from the side if you want to reduce the midrange (around 1 to 2 kHz). If
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Microphone Techniques
8
the ceiling is low, nail a square yard of acoustic foam up there to prevent
reflections.
If you have to mike close—say, for a singing fiddler—aim the mic
horizontally at the mouth about 6 inches away (Figure 8.20), or aim the
mic at the player’s chin from 1 foot above the fiddle. The mic will pick
up both the singer and the fiddle.
If you need more isolation, try a mini omni mic. Wrap its cable in
foam rubber (or a windscreen) 1–1/2 inches from the capsule. Wedge the
foam under the tailpiece, and position the mic capsule halfway between
the tailpiece and bridge, a half inch over the body (Figure 8.21). If necessary, cut a little at 3 kHz to reduce harshness and boost around 200 Hz for
warmth. Another option is to clip the mic to the tailpiece and mount it
over an f-hole.
A good spot for a pickup is on the left side of the top (player’s view),
on the player’s side of the bridge.
To record a classical violin solo, try a stereo mic (or a stereo pair) 5
to 15 feet away in a reverberant room.
String Section
Place the strings in a large, live room and mike them at distance to pick
up a natural acoustic sound. A common mic choice is a condenser with
a flat response. First try a stereo mic or stereo pair of mics about 4 to 20
feet behind the conductor, raised about 15 feet.
MINI OMNI
MIC PLACEMENTS
ON THE FIDDLE
OVER
F-HOLE,
CLIPPED TO
TAILPIECE
BETWEEN
TAILPIECE
AND BRIDGE
Figure 8.21
Two ways to close-mike a fiddle for isolation.
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Practical Recording Techniques
If the room is noisy or too dead, or the balance is poor, you’ll need
to mike close and add digital reverb. Try one mic on every two to four
violins, 6 feet off the floor, aiming down. Same for the violas. Mike the
cello about 1 to 2 feet from the bridge, to the right side between the bridge
and f-hole. When you mix the strings to stereo, pan them evenly between
the monitor speakers. Spread them left, center, and right to make a
“curtain of sound.” If you can spare only one track for the strings, use a
stereoizer effect during mixdown.
String Quartet
Record a quartet in stereo using a stereo mic or a pair of mics. Place
them about 6 to 10 feet away to capture the room ambience. The monitored instruments should not spread all the way between speakers. If
you want to narrow the stereo stage, angle or space the mics closer
together.
Bluegrass Band and Old-Time String Band
Suppose you’re recording a group that has a good acoustic balance. Try
a stereo mic or stereo pair of mics about 3 feet away and 6 feet high (lower
if the group is seated). Move the players toward or away from the mics
to adjust their balance.
You’ll have more control if you mike all the instruments up close
and mix them. This also gives a more “commercial” sound. The production style aims for a natural timbre on all the instruments, either with no
effects or with slight reverb.
Harp
Use a condenser mic with a flat response. If the harp is playing with an
orchestra, mike the harp about 18 inches from the front of the soundboard, or 18 inches from the player’s left hand. You can mike a harp solo
about 4 feet over the top.
Tape a mini omni condenser mic to the soundboard if you need more
isolation. A mic on the inside of the soundboard has more isolation; a mic
on the outside sounds more natural. Also try a cardioid condenser
wrapped in foam, stuck into the center hole from the rear.
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Microphone Techniques
8
Horns
“Horns” in studio parlance refers to the brass instruments: trumpets,
cornets, trombones, baritones, french horns, and tubas.
All the brass radiate strong highs straight out from the bell, but do
not project them to the sides. A mic close to and in front of the bell picks
up a bright, edgy tone. To mellow out the tone, mike the bell off-axis with
a flat-response mic (Figure 8.22). The sound on-axis to the bell has a lot
of spiky high harmonics that can overload a condenser mic, mixer input,
or analog tape. That’s another reason to mike off-axis.
Mike the trumpet with a dynamic or ribbon mic to take the edge off
the sound. Use a condenser mic if you want a lot of sizzle. Mike about
1 foot away for a tight sound; mike several feet away for a fuller, more
dramatic sound.
You can pick up two or more horns with one microphone. Several
players can be grouped around a single omni mic, or around a stereo pair
of mics. The musicians can play to a pair of boundary mics taped on the
control-room window or on a large panel.
Record a classical brass quartet in a reverberant room. Use a stereo
mic, or a stereo pair of mics, about 6 to 12 feet away.
Saxophone
A sax miked very near the bell sounds bright, breathy, and rather hard
(Figure 8.20). Mike it there for best isolation. To get a warm, natural
sound, mike the sax about 1–1/2 feet away, halfway down the wind
column (Figure 8.23). Don’t mike too close, or else the level varies when
MELLOW
BRIGHT
TRUMPET – TOP VIEW
Figure 8.22
Miking for trumpet tone control.
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Practical Recording Techniques
Figure 8.23
Two ways to mike a saxophone.
TROMBONES
DRUMS
BASS
TRUMPETS
DI
GUITAR
SAXES
PIANO
MUSIC STANDS
Figure 8.24
Typical miking setup for big-band jazz.
the player moves. A compromise position for a close-up mic is just above
the bell, aiming at the holes. You can group a sax section around one mic.
Figure 8.24 shows a typical miking setup for big-band jazz. It uses
the techniques already described for the drums, bass, piano, electric
guitar, trumpet, and sax.
Woodwinds
With woodwinds, most of the sound radiates not from the bell, but from
the holes. So aim a flat-response mic at the holes about 1 foot away
(Figure 8.25).
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Microphone Techniques
8
MIC
Figure 8.25
Miking a clarinet from the side.
FLUTE
TOP
VIEW
MIC
MINI OMNI
MIC
FRONT VIEW
Figure 8.26
Two methods of miking a flute.
When miking a woodwind section within an orchestra, you need to
reject nearby leakage from other instruments. To do that, try aiming a
bidirectional mic down over the woodwind section. The side nulls of the
mic cut down on leakage.
To pick up a flute in a pop-music group, try miking a few inches
from the area between the mouthpiece and the first set of finger holes
(Figure 8.26). You may need a pop filter. If you want to reduce breath
noise, roll off high frequencies or mike farther away. You also can attach
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Practical Recording Techniques
a mini omni mic to the flute a few inches above the body, between the
mouthpiece and finger holes.
For classical music solos, try a stereo pair 4 to 12 feet away.
Harmonica, Accordion, and Bagpipe
One way to mike a harmonica (harp) is to use a cardioid dynamic mic
with a ball grille. Place the mic very close to the harmonica or have the
player hold it. A condenser mic about 1 foot away gives a natural sound.
To get a bluesy, dirty sound, use a “bullet”-type harmonica mic or play
the harmonica through a miked guitar amp.
For an accordion, try a mic about 6 to 12 inches from the sound holes
near the keyboard. Some accordions have sound holes on both sides, so
you’ll need two mics. Follow the 3 : 1 rule. The distance between mics
should be at least three times the mic-to-source distance. One end of the
accordion is in constant motion, so you might want to attach a mini omni
mic to that end. A solo accordion or concertina could be miked with a
stereo pair of flat-response cardioid condenser mics about 3 to 6 feet in
front.
A bagpipe has two main sound sources: the chanter, which the musician plays with the fingers, and the drone pipes, which make a steady
tone. Mike the chanter about a foot away from the side, and mike the
drone pipes a foot from the end. Again, follow the 3 : 1 rule. You could
also mike the bagpipe a few feet away with one mic.
Lead Vocal
The lead vocal is the most important part of a pop song, so it’s critical
to record it right. First set up a comfortable environment for the
singer. Put down a rug, add some flowers or candles, dim the lights. Set
up a good cue mix with effects to help the singer get into the mood of
the song.
You might want to turn off the reverb in the singer’s headphones;
this makes it easier to hear pitch. If the vocalist is singing flat, reduce their
headphone volume, and vice versa.
With any vocal recording, there are some problems to overcome, but
we can deal with them. Among these are proximity effect, breath pops,
wide dynamic range, sibilance, and sound reflections from the music
stand. Let’s look at these in detail.
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Microphone Techniques
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Miking Distance
When you sing or talk close to most directional mics, the microphone
boosts the bass in your voice. This is called the proximity effect. We’ve
come to accept this bassy sound as normal in a PA system, but the effect
just sounds boomy in a recording.
To prevent boomy bass, mike the singer at a distance, about 8 inches
away (Figure 8.27). A popular mic choice is a flat-response condenser mic
with a large diaphragm (1–1/4-inch diameter). As always, you can use
any mic that sounds good to you. If the mic has a bass rolloff switch, set
it to “flat.”
Singers should maintain their distance to the mic. I ask the singer to
spread the fingers, touch lips with the thumb, and touch the mic with the
pinky. The hand forms a spacer for keeping constant distance.
Some singers can’t help but “eat” the mic. You can mike them at
distance, and also give them a dummy mic to hold while singing.
If you must record the singer and the band at the same time—as in
a concert—you’ll have to mike close to avoid picking up the instruments
with the vocal mic. Try a cardioid mic with a bass rolloff and a foam pop
filter. The sound will be bassy because of proximity effect, so roll off the
excess lows at your mixer. For starters, try -6 dB at 100 Hz. Some mics
have a bass filter switch for this purpose. Aim the mic partly toward the
singer’s nose to prevent a nasal or closed-nose effect. This close-up
method works well if you want an intimate, breathy sound.
When recording a classical-music singer who is accompanied by an
orchestra, place the mic about 1 to 2 feet away. If the singer is a soloist
(maybe accompanied by piano), use a stereo pair about 8 to 15 feet away
to pick up room reverb.
Figure 8.27
Typical miking technique for a lead vocal.
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Practical Recording Techniques
Breath Pops
When you sing a word with “p” or “t” sounds, a turbulent puff of air
shoots out of the mouth. The puff hits the mic and makes a thump or
small explosion called a pop. To reduce it, put a foam-plastic pop filter
on the mic. Some mics have a ball grille screen to cut pops, but foam
works better. The pop filter should be made of special open-cell foam to
pass high frequencies. For best pop rejection, allow a little air space
between the foam and the front of the mic grille.
Foam pop filters reduce the highs a little. So they should be left off
instrument mics, except for outdoor recording or dust protection. Pop
filters do not reduce breathing sounds or lip noises. To get rid of these
problems, mike farther away or roll off some highs.
The most effective pop filter is a hoop with a nylon stocking
stretched over it (Figure 8.27) or a disk of perforated metal. You can buy
those, or make one with a coat hanger and a crochet hoop. Place the filter
a few inches from the mic.
Another way to get rid of pop is to put the mic at forehead height,
aiming at the mouth. This way the puffs of air shoot under the mic and
miss it. Make sure the vocalist sings straight ahead, not up at the mic, or
the mic will pop.
Wide Dynamic Range
During a song, vocalists often sing too loud or too soft. They blast the listener or get buried in the mix. That is, many singers have a wider
dynamic range than their instrumental backup. To even out these extreme
level variations, ask the singer to use proper mic technique. Back away
from the mic on loud notes; come in closer for soft ones. Or you can ride
gain on singers: gently turn them down as they get louder, and vice versa.
Another solution is to pass the vocal signal through a compressor,
which acts like an automatic volume control. Plug the compressor into
the vocal channel’s insert jacks. A typical compressor setting for vocals is
a 2 : 1 ratio, -10 dB threshold, and about 3 to 6 dB of gain reduction. Of
course, you should use whatever settings are needed for the particular
singer. Track 26 on the enclosed CD demonstrates vocal compression, as well as
breath pops and the effects of miking distance on recorded vocals.
If the singer moves toward and away from the mic while singing,
the average level will go up and down. Try to mike the singer at least 8
inches away, so that small movements of the singer won’t affect the level.
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8
If you must mike close to prevent leakage or feedback, ask the vocalist to sing with lips touching the foam windscreen to keep the same
distance to the mic. Turn down the excess bass using your mixer’s lowfrequency EQ (typically -6 dB at 100 Hz).
Sibilance
Sibilance is the emphasis of “s” or “sh” sounds, which are strongest
around 5 to 10 kHz. They help intelligibility. In fact, many producers like
sizzly “s” sounds, which add a bright splash to the vocal reverb. But the
sibilance should not be piercing or strident.
If you want to reduce sibilance, use a mic with a flat response—
rather than one with a presence peak—or cut the highs little around
8 kHz on your mixer. Better yet, use a de-esser signal processor or plugin, which cuts the highs only when the singer makes sibilant sounds.
Reflections from the Music Stand and Ceiling
Suppose that a lyric sheet or music stand is near the singer’s mic. Some
sound waves from the singer go directly into the mic. Other sound waves
reflect off the lyric sheet or music stand into the mic (Figure 8.28, top).
Figure 8.28
Preventing reflections from a music stand.
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Practical Recording Techniques
The delayed reflections will interfere with the direct sound, making a
colored tone quality like mild flanging.
To prevent this, lower the music stand and tilt it almost vertically
(Figure 8.28, bottom). This way, the sound reflections miss the mic.
If your studio has a low ceiling, the recorded vocal might have a
colored tone quality due to phase cancellations from ceiling reflections.
Try putting the mic lower and use a hoop-type pop filter. Also put a 3foot square of acoustic foam on the ceiling over the singer and mic.
Vocal Effects
Some popular vocal effects are stereo reverb, echo, and doubling. You can
record real room reverb by miking the singer at a distance in a hardsurfaced room. Slap echo provides a 1950s rock ‘n’ roll effect. Often a
vocal is mixed dry, with no reverb. A little distortion might even be effective on some songs. You might try a vocal processor, which offers a
variety of effects. Try different EQ or different effects on each section of
a song.
Doubling a vocal gives a fuller sound than a single vocal track.
Overdub a second take of the vocal on an empty track, in sync with the
original take. During mixdown, mix the second vocal take with the original, at a slightly lower level than the original. You can double a vocal
track by running it through a digital delay set at 15 to 35 msec, or through
a pitch shifter that is detuned 10 to 15 cents.
Background Vocals
When you overdub background vocals (harmony vocals), you can group
two or three singers in front of a mic. The farther they are from the mic,
the more distant they will sound in the recording. Pan the singers left and
right for a stereo effect. Because massed harmonies can sound bassy, roll
off some lows in the background vocals.
If you want independent control of each background singer, give
each one a close-up mic and record them with separate mixer channels
or separate tracks.
Barbershop or gospel quartets with a good natural blend can be
recorded with a stereo mic or stereo pair of mics about 2 to 4 feet away.
If their balance is poor, close-mike each singer about 8 inches away, and
balance them with your mixer. This also gives a more “commercial”
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Microphone Techniques
8
sound. If you close-mike, spread the singers at least 2 feet apart to prevent
phase cancellations.
Spoken Word
The tips given earlier for a lead vocalist also apply to recording the
spoken word. Be sure to keep the miking distance constant and use a
hoop-type pop filter. To prevent sound reflections into the mic, put the
script on a padded music stand that is angled almost vertically, and put
the mic in the plane of the stand near the top edge. Fold up a corner of
each script page to form a handle for turning pages silently.
The engineer and announcer should both have the same script. Mark
the beginning of each misread sentence. The announcer should re-read
each misread sentence from the beginning to make editing easier.
Choir and Orchestra
Figure 8.29 shows three ways of miking a choir. If the mics will also be
used for PA, or if the venue is noisy or sounds bad, try miking close, pan
the mic as desired, and add artificial reverb (Figure 8.29A). Otherwise,
try a near-coincident pair of cardioid mics (Figure 8.29B) or a pair of omni
MIC
2 TO 4 MICS
1.5 FT.
A
CHOIR
SIDE VIEW
FRONT VIEW
CHOIR (TOP VIEW)
B
12-20 FT.
CARDIOID
PAIR
1.5 - 3 FT.
CHOIR
CHOIR (TOP VIEW)
C
8-15 FT.
OMNI
PAIR
Figure 8.29 Choir miking suggestions. (A) Close-up panned mics. (B) Nearcoincident stereo pair. (C) Spaced stereo pair.
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Practical Recording Techniques
mics spaced about 2 feet apart (Figure 8.29C). Adjust the mic-to-choir
distance until you hear the desired amount of hall acoustics in your
monitors.
See Chapters 18 and 19 for suggestions on miking an orchestra.
Summary
We can sum up mic placement like this: If leakage or feedback are problems, place the mic near the loudest part of the instrument, and add EQ
to get a natural sound. Otherwise, place the mic in various spots until
you find a position that sounds good over your monitors. There is no
single “correct” mic technique for any instrument. Just place the mic
where you hear the desired tonal balance and amount of room reverb.
Try the techniques described here as a starting point, then explore
your own ideas. Trust your ears! If you capture the power and excitement
of electric guitars and drums, if you capture the beautiful timbre of
acoustic instruments and vocals, you’ve made a successful recording.
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9
DIGITAL RECORDING
In the past, everything was recorded on analog recorders. The magnetic
particles on tape were oriented in patterns analogous to the audio waveform. In contrast, digital recorders convert the audio signal to a numerical code of ones and zeros.
Let’s venture into the world of digital audio. We’ll overview how
digital recording works, explore 2-track digital recorders, and explain
multitrack digital recorders. Chapter 13 covers computer recording in
detail.
Analog versus Digital
Analog and digital recorders don’t sound the same. Analog decks sound
reasonably accurate, but they add a little warmth to the sound. It’s due
to slight third harmonic distortion, head bumps (bass boost), and tape
compression. Analog decks also add some tape hiss, frequency response
errors, wow and flutter, modulation noise, and print-through.
Digital recorders don’t have these problems, so they sound very
clean. Although older digital recorders sounded harsh compared to
analog, they improved with each generation. In particular, digital
recorders that can record at 24 bits and 96 kHz can sound just as smooth
as analog.
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Practical Recording Techniques
Compared to analog recorders and open-reel tape, digital recorders
and their tape tend to cost less, are smaller, allow easier location of timing
information, and allow easier loading of the recording medium.
Digital Recording
Like an analog tape deck, a digital recorder puts audio on a magnetic
medium, but in a different way. Here’s what happens in the most
common digital recording method—pulse code modulation or PCM:
1. The signal from your mixer (Figure 9.1A) is run through a lowpass
filter (anti-aliasing filter), which removes all frequencies above
20 kHz.
2. Next, the filtered signal passes through an analog-to-digital (A/D)
converter. This converter measures (samples) the voltage of the
audio waveform several thousand times a second (Figure 9.1B).
3. Each time the waveform is measured, a binary number (made of 1’s
and 0’s) is generated that represents the voltage of the waveform at
the instant it is measured (Figure 9.1C). This process is called quantization. Each 1 and 0 is called a bit, which stands for binary digit.
The more bits that are used to represent each measurement (the
higher the bit depth), the more accurate the measurement is.
4. These binary numbers are stored on the recording medium as a
modulated square wave recorded at maximum level (Figure 9.1D).
For example, the numbers can be stored magnetically on a hard disk.
The playback process is the reverse:
1. The binary numbers are read from the recording medium (such as
a hard disk).
2. The digital-to-analog (D/A) converter translates the numbers back
into an analog signal made of voltage steps.
3. An anti-imaging filter (lowpass filter) smooths the steps in the
analog signal, resulting in the original analog signal.
Digital recording reduces noise, distortion, speed variations, and
data errors. Because the digital playback head reads only 1’s and 0’s, it is
insensitive to the magnetic medium’s noise and distortion. During
recording and playback, numbers are read into a buffer memory and read
out at a constant rate, eliminating speed variations in the rotating media.
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Digital Recording
Figure 9.1
9
Digital recording by pulse code modulation (PCM)
Reed-Solomon coding during recording, and decoding during playback,
corrects for missing bits by using redundant data.
If a digital recording is on a defective medium such as a scratched
compact disc, errors (missing samples) can occur. Usually these errors can
be corrected by interpolation. This algorithm looks at data before and
after the blank sample and “guesses” what its value should be. If the
errors are too extended to correct, the resulting audio has a silent spot or
a burst of noise.
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Practical Recording Techniques
Almost all digital recording devices employ the same A/D, D/A
conversion process, but use different storage media: a DAT machine
records on tape, a hard-disk drive records on magnetic hard disk, a
compact disc and DVD recorder record on an optical disc, a memory
recorder records onto a flash memory card, and a sampler records into
computer memory. The sound quality of any of these devices depends
mainly on its A/D and D/A converters.
Digital audio is recorded on a computer hard drive as a wave file
or AIFF file. Both are standard formats for audio files. Wave (.wav) is for
PC; AIFF (Audio Interchange File Format) is for Mac. Both formats use
linear PCM encoding, with no data compression (explained in Chapter
20). Two wave formats are Riff and Broadcast wave, which facilitates
interchange of program material between audio workstations.
Bit Depth
As we said, the audio signal is measured many thousand times a second
to generate a string of binary numbers (called words). The longer each
word is (the more bits it has), the greater is the accuracy of each measurement. Short words give poor resolution of the signal voltage (high
distortion); long words give good resolution (low distortion). Bit depth
or resolution are other terms for word length.
A word length of 16 bits is adequate (but not optimum) for hi-fi
reproduction. It is the current standard for CDs. Some digital recorders
offer 20- or 24-bit word lengths. More bits sound smoother and more
transparent, but need more disk storage space and a faster hard drive.
CDs sound better when made from 24-bit recordings.
Sampling Rate
Sampling rate is the rate at which the A/D converter samples or
measures the analog signal while recording. For example, a rate of 48 kHz
is 48,000 samples per second; that is, 48,000 measurements are generated
for each second of sound. The higher the sampling rate, the wider
the frequency response of the recording. According to the Nyquist
theorem, the upper frequency limit is one-half the sampling rate.
Compact discs use a 44.1-kHz sampling rate, so their frequency response
extends to 22.05 kHz.
Sampling rate for high-quality audio can be 44.1 kHz, 48 kHz,
88.2 kHz, 96 kHz, or 192 kHz. Higher sampling rates sound smoother
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9
Digital Recording
and more transparent but need more disk storage space and a faster hard
drive. CD quality is 44.1 kHz/16 bits. A 96-kHz sampling rate can be used
on the DVD. State-of-the-art is Super Audio CD or linear PCM at
192 kHz/24 bits (but you’re more likely to see 96 kHz/24 bits).
In summary, a digital audio system samples the analog signal
several thousand times a second, and quantizes (assigns a value to) each
sample. Sampling rate affects the high-frequency response. Bit depth
affects the dynamic range, noise, and distortion.
In a digital transmission, the two channels of a stereo program are
multiplexed. That is, one word from channel 1 is followed by one word
from channel 2, which is followed by one word from channel 1, and
so on.
Data Rate and Storage Requirements
The data rate of digital audio (in bytes per second) is
Bit depth/8 ¥ sampling rate ¥ number of tracks.
Divide by 1,048,576 to get megabytes (MB) per second. For example, the
data rate of a 24-bit/44.1-kHz recording of 16 tracks is
(24/8 ¥ 44,100 ¥ 16)/1,048,576 = 2 MB/sec.
Recording digital audio on a hard drive consumes a lot of space. The
storage required is
Bit depth/8 ¥ sampling rate ¥ number of tracks ¥ 60
¥ number of minutes
Divide by 1,048,576 to get MB. Divide MB by 1024 to get gigabytes (GB).
For example, suppose you record a concert at 24 bits, 44.1 kHz, 16 tracks,
for 2 hours. The hard-drive space needed is
(24/8 ¥ 44,100 ¥ 16 ¥ 60 ¥ 120)/1,048,576 = 14,534.9 MB or 14.2 GB.
Digital Recording Level
In a digital recorder, the record-level meter is a peak-reading LED or LCD
bar graph meter that reads up to 0 dBFS (FS means full scale). In a 16-bit
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Practical Recording Techniques
digital recorder, 0 dBFS means all 16 bits are on. In a 24-bit digital
recorder, 0 dBFS means that all 24 bits are on. The OVER indication means
that the input level exceeded the voltage needed to produce 0 dBFS, and
there is some short-duration clipping of the output analog waveform.
This clipping can sound really nasty. Some manufacturers calibrate their
meters so that 0 dBFS is less than 16 or 24 bits on; this allows a little headroom. When you set the recording level, it’s a good idea to aim for -5 or
-3 dB maximum so that unexpected peaks don’t exceed 0 dBFS. If you’re
making a 24-bit recording, the recording level is not very critical because
a 16-bit signal is at -48 dBFS!
The Clock
Each digital audio device has a clock that sets the timing of its signals.
The clock is a series of pulses running at the sampling rate. When you
transfer digital audio from one device to another, their clocks must be
synchronized. One device must provide the master clock and the other
must be the slave. If you send digital audio from one device, the receiver
syncs to the sender’s clock, which is embedded in its digital signal.
If a device (such as a digital mixer) is receiving data from many
sources at once, select one device as the word clock source. Connect its
word clock output to the input of a word-clock distribution unit. Connect
a cable from each output of the distribution unit to the word-clock
input of each of the other devices. That way all the devices will be
synchronized.
Digital Audio Signal Formats
Digital audio signals come in four basic formats: AES/EBU, S/PDIF,
ADAT Lightpipe, and TDIF. Let’s look at each one.
• AES/EBU (also called AES3–1985): 2-channel professional format.
Uses a balanced 110-ohm shielded twisted-pair cable with XLR-type
connectors. The signal contains digital audio plus a word clock, or
a separate word clock on another cable. The AES/EBU cable can be
up to 200 m long. If the word clock cable is under 25 feet, it can be
an unbalanced 75-ohm cable with BNC connectors. Word-clock
cables over 25 feet should use balanced 110-ohm AES digital cable.
• S/PDIF Sony/Philips Digital Interface (also called EIAJ CP-340 Type
II or IEC 958): 2-channel consumer or semi-pro format. The signal
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Digital Recording
9
contains digital audio plus an embedded word clock signal. Uses a
75-ohm coaxial cable with RCA or BNC connectors, or a fiber optic
cable with a Toslink connector. Optical interfaces prevent ground
loops and cable losses. AES/EBU signals are higher voltage than
S/PDIF.
• ADAT Lightpipe: The Alesis ADAT modular digital multitracks use
a Lightpipe, which sends 8 channels of digital audio in and out on
a single optical cable with TOSLINK connectors. Every 8 channels
of transfer requires a separate Lightpipe cable.
• Tascam TDIF (Tascam digital interface): The Tascam DA-88 and
similar modular digital multitracks use a multiconductor cable with
standard DB-25 connectors. TDIF sends 8 channels of digital audio
in and out on a single cable, which can be up to 5 m long.
Converting Signal Formats
AES and S/PDIF signals are similar but not necessarily compatible. You
can convert one to the other using a format converter. Some sound cards
and digital mixers do this conversion. Lightpipe and TDIF signals can be
converted as well.
Some digital audio devices do not implement AES or S/PDIF
correctly, so they do not interface with some other devices.
Dither
Your HD recorder, software, and digital mixer may run at 24 bits, but the
result ends up on a 16-bit CD. When you save a 24-bit audio file as a 16bit file to transfer to CD, those last eight bits are truncated or cut off. The
result may be a grainy static sound at very low levels. This distortion can
be prevented by adding low-level random noise (dither) to the signal.
Let’s explain.
A 24-bit resolution can accurately capture the quietest parts of a
musical program: very low-level signals such as the end of long fades
and reverb tails. But truncation of that signal to 16 bits makes those lowlevel signals sound grainy or fuzzy, because 16 bits is a less accurate measurement of the analog waveform than 24 bits. This fuzzy sound, called
quantization distortion, doesn’t exist at normal levels.
What causes this distortion? Each digital word is made of a certain
number of bits. During quantization, the A/D converter assigns the
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Practical Recording Techniques
closest possible digital number to represent the measured voltage of each
sample. The last or rightmost bit (least significant bit or LSB) switches on
or off depending on whether the converter rounds the word value up or
down. If this switching occurs in the 16th bit, it may be faintly audible as
a fuzzy noise during quiet passages.
Also, a 24-bit recording has 256 possible levels in the lower 8 bits.
But after the signal is truncated to 16 bits, that resolution is lost.
To solve this problem, dithering adds random noise (random 1’s and
0’s) to the lowest 8 bits of the 24-bit signal (at about -100 dB) before they
are truncated to 16 bits. That noise modulates the 16th bit with some 24bit information (bits 17 through 24) in the form of pulse-density modulation. The average value of that modulated square wave is recovered by
a low-pass filter. Then most of the 24-bit sound quality is restored, and
the quantization distortion changes to a smooth hiss.
To make that added hiss less obvious, noise shaping is used. Noise
shaping applies an oversampling filter to the noise, which reduces its
level in the midrange where our ears are most sensitive, and increases its
level in the high frequencies where it’s less audible.
Compared to a truncated signal, a truncated-and-dithered signal
sounds slightly more transparent. Fades and reverb tails sound smoother,
and there’s more sonic detail. Signals below the noise floor become
audible.
For best sound quality, apply dither only once when you convert a
high bit-depth source to its 16-bit CD format. For example, record at 24
bits and stay there through the entire project, then dither to 16 bits as the
very last step just before you burn a CD. Do not re-dither material that
has already been dithered—switch off any dithering. When doing a crossfade between two files, make sure each is non-dithered, then add dither
after the crossfade during mastering.
To hear the effects of dithering, start with a clean 24-bit recording,
reduce its level 50 dB in your editing software, and export it as a 16-bit
file. Export it in three ways: without dither, with dither, and with noise
shaping added. Next, normalize the exported recordings so that the
highest peak hits 0 dBFS. Then listen to the resulting 16-bit files at high
level over headphones. Compare the processing and use whatever
sounds best. Generally, a signal that is truncated with no dither is accompanied by a rough, grainy noise. A signal that is truncated and dithered
is accompanied by smooth, quiet hiss or silence.
Here is another application where dithering is necessary. Digital
signal processing—such as level changes, EQ, or reverb—is done in a
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Digital Recording
9
processor chip that performs mathematical calculations on each sample.
These calculations create longer word lengths than existed in the original
program. But the processor must output the same word length as the
original signal. For example, a 16-bit audio file might result in words 32
bits long after processing. These 32-bit words must be converted back to
16 bits at the processor output. The extra bits must be truncated or cut
off, but this causes distortion. So dithering is done automatically in the
D/A converter. It can be set manually in some digital editing programs
and outboard D/A converters. This dithering is performed only once, just
before the output of the processor.
With good dithering algorithms, it’s possible to preserve most of the
24-bit quality (ultra-low distortion and fine detail) when converting to 16
bits. One such system is Sony Super Bit Mapping. Another is the POWrTM Psychoacoustically Optimized Word-Length Reduction algorithm
from the Pow-r Consortium LLC. It reduces the high-resolution, higher
word lengths (20 to 32 bit) to a CD-standard, 16-bit format while retaining the transparency of the high-resolution recording. In other words, the
16-bit CD sounds like the original 24-bit recording.
In addition, you could send audio through a multichannel 24-bit
A/D converter, process it with POW-r, and record the result onto a 16-bit
recorder. The playback would sound much like a 24-bit recording.
Jitter
Jitter is an instability in the timing of digital bits. It causes small changes
in the audio waveform’s shape, resulting in a slight veiling of the sound
(low-level distortion). A jitter spec under 250 picoseconds is considered
inaudible. Accurate A/D and D/A conversions rely on the clock precisely
sampling the analog signal at equal time intervals. Any change between
the sample times, even nanoseconds, causes audible amplitude errors
(distortion).
Jitter occurs during A/D and D/A conversion, but not during
digital-to-digital copies. One cause of jitter is analog noise and crosstalk
in the recording system. They affect the switching times and switching threshold of the clock, causing frequency modulation of the
clock. They also affect the analog filters and oscillators used in the clock’s
phase locked loops (PLLs). Jitter is also caused by inadequate digital
cables. These cables pick up hum and noise, and introduce phase shift
and high-frequency attenuation, which degrade the timing of the digital
signal.
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Practical Recording Techniques
To reduce jitter:
• Use high-quality clock sources with low jitter specs (under 1
nanosecond). Usually the internal clock in A/D and D/A converters has less jitter than an external clock, such as AES/EBU or word
clock.
• Use high-quality, well-shielded digital cables (ideally, 75-ohm RG59
video cables), and make them as short as possible.
• Keep analog and digital cabling separate.
• Use the A/D converter’s internal clock as the master clock. Feed its
AES or word-clock output to other slave devices in your studio to
keep them in sync. If you use a separate word-clock cable, make it
the same length as the digital audio cable.
Digital Transfers or Copies
When you send a digital audio signal in real time from one device to
another, they must be set to the same sampling rate. For example, if the
digital signal from a multitrack recorder is 48 kHz, the digital mixer it
feeds must also be set to 48 kHz. In a digital transfer, the sending device
usually is the master, and the receiving device is the slave. Normally you
can set the slave to automatically lock onto the sampling rate of the
master. Set the master device to Internal Clock, and set the slave device
to External Clock. Or set the slave’s clock source to whatever device the
master is.
The word length (number of bits) of digital transfers is less critical.
As long as the two machines handle the same digital format, transfers of
any word length can be done. Formats for digital transfer are S/PDIF,
AES/EBU, ADAT Lightpipe, and Tascam TDIF.
It’s okay to send a lower bit signal to a higher bit device. For instance,
feed a 16-bit signal from a DAT into a 24-bit digital mixer. The mixer will
add more zeroes to fill out the digital word, with no effect on sound
quality. It’s also no problem to feed a device more bits than it can hold.
The receiving device ignores the extra bits. For example, if you send a 24bit signal to a 16-bit recorder, the last 8 bits will be truncated or cut off.
Truncation adds slight distortion, but this can be reduced by adding
dither—low-level noise—to the signal before truncating. So it’s best to
keep the word length as long as possible as you’re working on a project.
Always apply dither before you reduce the word length, and only then.
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Digital Recording
9
What if you have a 48K recording that you want to release on CD?
The CD mastering engineer can (1) convert the 48K digital signal to 44.1K,
which might degrade the sound, or (2) use the analog output of his or
her playback machine, and convert the analog signal to digital at 44.1K.
This may or may not sound better.
To or from DAT or MDM tape and to or from CD-Rs are digital audio
transfers that might or might not create perfect clones because of inadequate error correction or interpolation errors.
Does a FireWire transfer of realtime audio contribute jitter? Not
really. With isochronous FireWire transfer, it’s relatively easy to generate
a very low-jitter D/A clock. “Isochronous” means that the data must be
delivered at a certain minimum data rate. Multimedia signal streams
require isochronous data flow to ensure that audio data is delivered as
fast as it is played and recorded.
When you copy a wave or aiff file rather than a digital audio signal,
the copy is a perfect clone of the original file. The file transfers much faster
than the real-time playback of the signal. Flawless file copies can be made
in these ways:
•
•
•
•
Inside a computer from one hard drive location to another
From one computer’s hard drive to another computer’s hard drive
Via Ethernet, USB, FireWire, or the Internet
Between computers via CD-R, Jaz, or Zip drive; floppy disks; or
Flash memory cards
The following data compression algorithms don’t lose any data, so
they don’t degrade audio quality:
•
•
•
•
•
•
Emagic’s Zap
Waves’ TrackPac
PKWare’s PKZIP
WinZip Computing’s WinZip
Aladdin Systems’ StuffIt
Meridian Lossless Packing (MLP)
2-Track Digital Recorders
Now that we overviewed digital recording, let’s look at digital recorders.
They come in 2-track and multitrack formats. The 2-track formats are
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Practical Recording Techniques
• DAT (rotating-head digital audio tape); this format is obsolete and
is not covered here
• Portable hard-drive recorder
• Digital Audio Workstation; this is a computer (usually a laptop) with
a sound card or other audio interface, plus recording software
• CD-R recorder
• MiniDisc recorder
• Memory recorder
We’ll look at each one. No matter which format you use, the sound
quality depends on the A/D converter and mic preamp (if any).
Portable Hard-Drive Recorder
This device (Figure 9.2) records onto a built-in hard drive. For example,
the Edirol R4 records up to 4 tracks simultaneously onto a 40-GB drive,
either MP3 or WAV files up to 24-bit/96 kHz. The unit has XLR/phone
inputs with phantom power, built-in stereo speakers, USB 2.0 interface to
a computer, waveform editing, limiting, and a compact-flash slot. See
Web site www.edirol.com.
Figure 9.2
182
A portable hard-drive recorder.
Digital Recording
9
The Digital Audio Workstation
The Digital Audio Workstation (DAW) is a computer running recording
software with a connected audio interface such as a sound card (Figure
9.3). A DAW allows you to record, edit, and mix audio programs entirely
in digital form. It can store up to several hours of digital audio or MIDI
data. You can edit this data with great precision on a computer monitor
screen. What’s more, you can add digital effects and perform automated
mixdowns. We’ll cover DAWs in detail in Chapter 13.
A laptop computer can make a great portable 2-track digital
recorder. Just add some recording software and an audio interface connected by USB or FireWire.
CD Recordable
Another form of digital recording is the compact disc. On your own
desktop, you can cut a CD by using a CD-R recorder (CD burner). It’s
exciting to hear one of these CDs playing your music with the purity of
digital sound. The sound quality meets or exceeds CD standards.
CD-R stands for compact disc recordable. This optical medium is
a write-once (nonerasable) format. CD-RW stands for compact disc rewritable; you can erase it and record a new program. Although any CD
MONITOR
HARD
DRIVE
PCI SLOT, USB PORT,
OR FIREWIRE PORT
COMPUTER
KEYBOARD
ALESIS
FIREPORT
I/O INTERFACE
(BREAKOUT BOX)
SOUND CARD
MOUSE
CONTROLLER WITH I/O
AUDIO INTERFACES (CHOOSE ONE)
Figure 9.3
A computer Digital Audio Workstation (DAW).
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Practical Recording Techniques
player or CD-ROM drive will play a CD-R, many CD players—especially
older ones—can’t play CD-RW discs. Most new CD-ROM drives support
CD-RW, but not all will read CD-RW discs at full speed. CD-RW blank
discs cost more than CD-R blank discs.
How can you use the CD-R format? You could make demos for your
own band, or make a one-off copy of your stereo mixes for clients. Use
the CD-R as a pre-master to send to a CD replicator. Another function is
to compile sound libraries of production music, samples, and sound
effects. If handled and stored with care, the CD format is a dependable
storage medium, so it’s a great way to archive your recordings.
CD-R Formats
Want to try CD-R? First you’ll be faced with two basic choices of CD-R
recorder:
1. A standalone CD-R recorder, sometimes called a consumer CD
recorder
2. A computer peripheral CD-R recorder, also called a computer CD
burner; you plug it into your computer system, or buy a computer
with a CD burner built in
Both types produce discs that sound equally good. Both types of
discs will play on any audio CD player.
The standalone CD recorder has everything you need in one chassis.
Inside is a CD transport, laser, and microprocessor. On the back are
analog and digital ins and outs. On the front are the level meters, recordlevel knob, display, and keypad. Because the standalone unit needs no
external computer, it’s user-friendly. Just connect your audio source containing an edited program, either on DAT, LP, or analog tape. Set the
recording level and start recording.
The standalone unit can write audio but not data. The 63-minute
blank discs it uses are the “Music CD-R” or “Digital Audio CD-R” format.
Prices for standalone CD-R writers start around $400.
A computer CD recorder costs less: about $100 and up. The unit
plugs into an EIDE or SCSI connector in your computer. It can write audio
or computer data. Its blank discs, called “CD-R” or “Data CD-R,” cost
less than 35 cents in quantity. (Music CD-Rs will work in a computer CD
burner as well.) Disc length is 74 (650 MB), 63 (550 MB), or 80 minutes
(700 MB). Some discs permit recording at up to 52 times real time if your
computer and hard drive are fast enough.
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The computer CD-R recorder also requires a CD recording program,
usually packaged with the recorder. You don’t have to use that program;
other ones are available that you might prefer. Be sure the program is
compatible with your recorder. You’ll also need a sound card and some
software to record audio onto hard disk.
Multi-drive CD burners let you record or copy several CDs at once.
CD-R Technology
While conventional CD players follow the Sony-Philips Red Book standard, CD-Rs conform to the Orange Book part II standard. Once recorded,
a CD-R disc meets the Red Book standard.
A recordable CD is the same size as a standard CD, but it is
more colorful. On top is a metal reflective layer; on the bottom is a recording layer made of blue cyanine dye or yellow (gold) phthalocyanine
dye. The blue layer appears green because of the gold layer behind
it. Yellow dye lasts a little longer in accelerated aging tests, and it may
work better with high-speed CD-R drives. A few other colors are available as well.
A blank CD-R is made of four layers:
1.
2.
3.
4.
Clear plastic (protects the metal layer)
Metal layer (gold, silver, or silver alloy, which reflects the laser light)
Dye (for the recording)
Clear plastic (protects the dye layer)
The dye fills a spiral groove which is etched in the bottom clearplastic layer. This groove guides the laser.
To record data on a disc, the laser melts holes in the dye layer. The
plastic layer flows into the holes to form pits. During playback, the same
laser reads the disc at lower power. At each pit, laser light reflects off the
metal layer. The reflected light enters the laser reader, which detects the
varying reflectance as the pits go by.
In contrast with a standard CD, a CD-R disc has two more data areas:
• The program calibration area (PCA). The CD recorder uses this area
to make a test recording, which determines the right amount of laser
power to burn the disc (4 to 8 milliwatts).
• The program memory area (PMA). This area stores a temporary
table of contents (TOC) as the CD-R tracks are assembled. The TOC
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is a list of the tracks, their start times, and the total program time.
The recorder uses the PMA for this information until it writes the
final TOC.
According to CD-R manufacturers, the expected lifetime of a CD-R
is about 70 to 100 years with careful handling. Avoid sunlight and high
temperatures. Be sure not to damage the label side of the disc by writing
on it with a ballpoint pen or pencil—use a soft felt-tip pen that is waterbased, such as a CD-marking Sharpie Store CDs vertically and keep them
in their cases. Avoid labels because the adhesive can attack the protective
plastic layer, and the paper might warp over time. CD-RW life expectancy
is claimed to be about 25 years.
CD-R Sessions, Disc-At-Once, and Track-At-Once
Before we look at the differences among CD-R recorders, we need to
understand the concept of a session. A session on disc is made up of a
lead-in, program area, and lead-out. Each session has its own TOC. Each
lead-in and lead-out consumes 13 MB of disc space.
With the multisession feature, you can write several sessions on a
disc at different times. This feature comes in handy when you need to
add information to a disc a little at a time. Only the first session on disc
will play on an audio CD player, so the discs are just for your own use
and not for distribution.
CD-R recorders also permit Disc-At-Once recording, in which the
entire disc must be recorded nonstop. You can’t add new material once
you write to the disc. With some software, Disc-At-Once lets you set the
length of silence between tracks (down to 0 seconds), and lets you control
how the tracks are laid out on disc. Use Disc-At-Once for all pro audio
work.
Most CD-R recorders allow Track-At-Once recording. They can
record one track (or a few tracks) at a time—up to 99 tracks. You can play
a partly recorded disc on a CD-R recorder, but the disc will not play on
a regular CD player until the final TOC is written. Track-At-Once is not
recommended for audio because it puts 2-second spaces and clicks
between audio tracks.
If you want no pauses between tracks (as on a live album), get a CDR writer with Disc-At-Once. Also get some software that can adjust the
pause length down to zero, or that can set the start ID of each song anywhere in the program. Note that a self-contained CD-R writer will copy
your edited program as it is, with or without pauses.
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A good CD-R writer has a buffer of at least 2 MB. Some writers
include SCMS copy code. Be sure that you can return the CD-R writer if
it proves to be unreliable.
How to Use a Standalone CD-R Writer
Let’s say that you have an edited recording of song mixes on a 2-track
recorder, and you want to copy them onto a CD by using a self-contained
CD-R writer.
Connect the 2-track recorder’s output to the CD-R writer’s input.
Use a Music CD-R or Digital Audio CD-R. Set your levels and begin
recording. Your program will copy to disc in real time.
Depending on the CD-R writer, the recording’s start IDs may or may
not convert to CD track numbers. If not, you can use a converter box, or
add the track numbers manually while you record.
Using a computer CD-R burner is covered in Chapter 15. For
more information on CD-R technology, see www.cdrfaq.org and
www.harmony-central.com/Features/CDRecorder/.
MiniDisc Recorder
A blank MiniDisc is a rewritable, magneto-optical medium read by a
laser. The disc itself is like a miniature compact disc inside a 2-1/2-inch
square housing. A write-protect tab on the housing prevents accidental
erasure. Estimated disc life is 30 years, but a strong magnet near the disc
can erase data.
Three types of blank discs are available: the regular 74-minute MiniDisc used in 2-track recorders, the Hi-MD 1-GB disc, and the MD Data
disc used in multitrack recorders.
Most MiniDisc devices record audio at 44.1 kHz, 16 bits, and some
at 24 bits.
To fit all this data on a small disc, MD recorders use a data compression scheme called Adaptive Transform Acoustic Coding (ATRAC). It
reduces by 5 : 1 the storage needed for digital audio. ATRAC is a perceptual coding method that omits data deemed inaudible due to masking.
For example, if an audio signal has two sounds that are about the
same frequency, and one sound is louder than the other, the quieter sound
will be inaudible due to masking. So ATRAC removes the quieter sound,
which would be inaudible anyway.
ATRAC has had several revision levels; the latest version (as of 2004)
is ATRAC3 Plus. The higher the version number, the better the sound.
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Some reviewers have claimed that ATRAC3 Plus sounds essentially the
same as CDs when playing a musical program. Earlier versions are said
to be near-CD in quality, and much better than MP3. All versions are
compatible.
Sound quality depends not only on the ATRAC version, but also on
the quality and bit depth of the A/D converter in the recorder. Although
the MiniDisc format uses data compression, its stereo digital output is
standard 16-bit S/PDIF.
There is a slight generation loss when ATRAC tracks are copied or
bounced. The signal is ATRAC-processed with each copy. After more than
five copies or so, the sound cumulatively begins to take on a mid-to-low
rumble and a high-frequency squeak.
MiniDisc recorders can make ATRAC-compressed copies of CDs
directly from the CD player’s digital output.
Introduced in 2004, Hi-MD recorders can record uncompressed
PCM audio (16-bit 44.1 kHz wave files) as well as ATRAC3 Plus audio.
They record on a 1 GB magneto-optical medium, and also on the original
MiniDiscs reformatted to double capacity (305 MB). A 1 GB disc can
record up to 1 hour and 34 minutes of uncompressed PCM audio. Hi-MD
recorders can be used as USB data drives for PCs. Recordings can be
uploaded very quickly to Windows PCs via SonicStage, Sony’s audio
transfer software. For more information, see www.minidisc.org.
Two-track recorders come in a portable style or a component style.
The portable MiniDisc WalkmanTM format is popular with news reporters
who need to carry a small, high-quality recorder in the field. Reporters
can edit the recording using buttons on the recorder.
Portable 2-track MD recorders have been used for documenting
musical groups at folk festivals. The recordist walks around the festival
recording various groups of musicians (with their permission, let’s
hope!). MiniDisc also offers an easy way to record school concerts, sound
effects, or your band’s gigs.
Can you use a Hi-MD MiniDisc to record a stereo master of your
mixdowns? You could, but CD-R and DAT masters are preferred. Also,
many mastering houses do not accept MiniDisc masters.
Memory Recorder
This is a portable digital recorder with no moving parts and no maintenance. It records onto a Flash memory card, such as Compact Flash, Smart
Media, Sony Memory Stick, or SD card. Here are some examples:
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The Marantz PMD670 records MP3 or uncompressed CD-quality
wave files (up to 48 kHz) on a Compact Flash card or IBM Microdrive. A
USB port downloads data quickly to your computer for editing. Two XLR
mic inputs with phantom power are included. You can record 6 hours of
uncompressed 16-bit/48-kHz wave audio on a 2-GB card. The unit allows
edit decision list (EDL) markings during record or playback. A smaller
model, PMD660, records to Compact Flash and has built-in mics. See Web
site www.d-mpro.com.
The Edirol R1 records MP3 or WAV files (up to 24-bit) onto
a Compact Flash card. It has a built-in mic, effects, metronome,
limiter, and tuner. Input is stereo mini phone. See Web site
www.edirol.com.
The Zoom PS-02 Palmtop Studio includes three audio tracks, drum
and bass machines, guitar multieffects, mixer, a built-in mic, and a tuner
in a chassis that fits in your pocket. Effective as a digital sketchpad
recorder, the PS-02 stores over 2 hours of program on a 128-MB Smart
Media card.
The Nagra Ares-PII is a handheld audio recorder that digitizes audio
with MPEG layer 2 compression or uncompressed PCM, and records to
Flash RAM. The RCX220 also has a USB port for file transfer to a PC for
editing. A phantom-powered mic input is included.
PocketREC is a PocketPC that works as a portable digital recorder.
On Flash memory it can record 16-bit, 48-kHz linear (uncompressed)
wave files. You can edit the audio and transfer data via wireless or wired
connections. The unit supports the PDAudio-CD interface described
below.
PDAudio is a compact memory recording system for pocket PCs
(PDAs) and laptop and desktop computers (Figure 9.4). It costs $400 to
$1000. The system includes:
• A stereo mic preamp/A/D converter of your choice, such as Core
Sound’s Mic2496
• An audio interface, such as Core Sound’s PDAudio-CF (turns a PDA
into a recorder by converting digital audio to Compact Flash format)
• A Personal Digital Assistant (PDA) of your choice, such as the
Compaq iPAQ Pocket PC
• An expansion card adapter for Compact Flash (CF) cards or PC cards
• Recording software, such as Core Sound’s PDAudio Recorder, Pocco
Software’s Wichita, or Gidluck Mastering’s Live2496
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Practical Recording Techniques
Figure 9.4 PDAudio-CF installed in an HP iPAQ Pocket PC. A Mic2496
preamp/converter is attached to the iPAQ.
• Storage device, such as Flash memory (SD, PC Card, or CF card) or
PC-card hard drive
Starting with a pocket PC (PDA), you plug in the PDAudio interface card, which accepts a stereo digital audio signal up to 24 bits/96 kHz.
You launch the recording software, and record audio onto a flash memory
card or PC card hard drive plugged into the PDA.
Multitrack Digital Recorders
So far we’ve covered 2-track digital recorders. Now we’ll consider the
multitrack digital recorders listed below:
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•
•
•
•
•
•
9
Modular Digital Multitrack (MDM)
Computer DAW (covered earlier)
Standalone hard-disk recorder
Hard-disk recorder-mixer
MiniDisc recorder-mixer
DVD recorder (see Chapter 19).
Modular Digital Multitrack
Shown in Figure 9.5, a Modular Digital Multitrack (MDM) records 8
digital tracks on a videocassette, using a rotating drum like a DAT
recorder. Two popular models are the Alesis ADAT-XL which records on
S-VHS tape, and the Tascam DA-88 or DA-78, which record on Hi-8 video
cassette tape. ADAT records up to 40 minutes on a single tape; DA-88
records up to 1 hour and 48 minutes.
With both types, you can sync several 8-track units by a cable to add
more tracks, 8 at a time. Unlike SMPTE time code, MDM sync does not
use up any tracks. MDM options include remote controls, remote editors,
circuit boards with enhanced converters, and circuit boards that allow
sync to SMPTE and MIDI.
To prevent data errors, be sure to format the MDM tape correctly.
Fast-forward the tape to the end, rewind to the top, then format the tape.
Clean the heads with a dry cleaning tape only when an error signal
appears, because cleaning tapes are abrasive and can wear out the heads.
It’s common to record music on an MDM, dump the MDM tracks to
computer hard disk for editing, then dump the edited tracks back to
MDM. Sound cards are available with Alesis Lightpipe or TASCAM TDIF
connectors for this purpose.
MDMs have been superceded by hard-disk recorders.
Figure 9.5
An MDM recorder.
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Practical Recording Techniques
Figure 9.6
HD recorder.
Hard-Disk (HD) Recorder
This device records and plays up to 24 tracks at once on a built-in hard
drive, just like the drive in your computer. The latest units record with
24-bit resolution and up to 96 kHz sampling rate. Some record 24 tracks
of 24-bit programs at sample rates of 44.1 and 48 kHz. They record 12
tracks of 24-bit recording at 88.2 and 96 kHz.
The HD recorder allows track editing, either on a built-in LCD
screen or on a plug-in computer monitor. Some HD recorders have builtin removable hard drives for backing up projects. See Figure 9.6.
HD Recorder-Mixer
Shown in Figure 9.7, this device records and plays up to 36 tracks on a
built-in hard drive. It’s also called a standalone DAW, personal digital
studio, or digital multitracker. The mixer includes faders (volume controls) for mixing, EQ or tone controls, and aux sends for effects (such as
reverb). An LCD screen displays recording levels, waveforms for editing,
and other functions. Some manufacturers of HD recorder-mixers are
Roland, Korg, Fostex, Boss, Yamaha, Akai, and Tascam.
Listed below are some features to look for in HD recorder-mixers.
• Number of tracks: 4 to 36. The more tracks you have, the more
instruments and vocals you can record on individual tracks.
• Number of tracks that can be recorded simultaneously: 8 to 24. If
you want to record an entire band at once, you need to record many
tracks at the same time.
• Bit depth: 16 to 24 bit. The more bits, the higher the sound quality.
• Sampling rate: 44.1 to 96 kHz. The higher the sampling rate, the
higher the sound quality. The latest units record with 24-bit resolution and up to 96-kHz sampling rate. Some record 24 tracks of
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JOG WHEEL
LCD SCREEN
FADERS
Figure 9.7
CONTROLS
An HD recorder-mixer.
•
•
•
•
•
24-bit programs at sample rates of 44.1 and 48 kHz. They record 12
tracks of 24-bit recording at 88.2 and 96 kHz.
Number and type of analog inputs and outputs, and digital inputs
and outputs. Balanced XLR or TRS phone-jack mic connectors are
preferred over unbalanced (TS) phone-jack connectors. Balanced
connections let you run longer mic cables without hum pickup.
Phantom power for condenser mics.
Number of built-in digital effects: Up to 8 stereo or 16 mono. Examples of effects are reverberation, echo, flanging, chorus, and compression. They add sonic excitement and a professional touch to
your productions. Some recorder-mixers have an expansion card
that accepts downloadable plug-in effects.
Types of EQ: 2- or 3-band, fixed or parametric. EQ means tone
control. A 2-band EQ adjusts bass and treble, and a 3-band adjusts
bass, midrange, and treble. A fixed-frequency EQ is less flexible than
a parametric or sweepable EQ, which lets you adjust the frequency
range you want to work on.
Backup options: Removable hard drive, CD-R.
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• Levels of undo: Up to 1000. The Undo function lets you undo an
editing change you just did. If you don’t like how an edit sounded,
you can press Undo and go back to the way things were before you
made the change.
• Number of locate points: Up to 1000. A locate point is a point in time
in the recording that you can have the recorder memorize and locate
later. For example, you might want to mark the time where the
beginning of a song is, so you can tap a button and go there instantly.
• Expansion ports for SMPTE and MTC sync, MDM interface, and
extra ins and outs. Beginners probably don’t need these features, but
they let you connect your multitracker to other devices.
• MIDI implementation: MIDI Machine Code (MMC), Control Change
(CC). These features let you control the mixer via MIDI commands.
• Types of synchronization: SMPTE, Word Clock, MTC, MIDI
Clock with Song Position Pointer, ADAT, DA-88, and RS-422. These
are various formats that you might want your multitracker to sync
with.
• Jog/shuttle wheel to “scrub” audio-play it slowly forward and backward to locate an edit point.
• Remote control.
• Automated mixing. A memory circuit in the multitracker remembers
your song-mix settings and mix changes. The next time you play the
song, the memory circuit resets the mixer to those settings automatically. Some multitrackers have motorized faders, so that the
faders move up and down just as they did when you adjusted them
while mixing.
• Editing (cut and paste, etc.). Editing lets you do all sorts of things
with the song arrangement. You might remove parts of songs that
you don’t want to keep, loop a drum part so that it repeats continuously, or copy a chorus to several points in a song.
• Video output that plugs into a computer monitor screen. During
editing, it’s a lot easier to see details in the sound waveform if you
can plug a large monitor into your multitracker.
• Mastering tools and CD-burning ability. In mastering you compile
a playlist of mixed songs from which you can create an album. Some
multitrackers include programs that let you record your songs on a
CD-R recorder, either external or built-in.
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• Number of virtual tracks (extra takes): Up to 800. A virtual track is
a 1-channel recording of a single take or performance on a randomaccess medium. Most random-access recorders let you record
several virtual tracks or takes of a single instrument, then select
which take you want to hear during mixdown. For example,
suppose you have a 16-track hard-disk recorder. You could record
up to 255 virtual tracks of a vocal on hard disk. Then during
mixdown, choose which virtual track will play as one of those 16
tracks. Some recorders can be set up to select parts of different
virtual tracks during playback. For example, play vocal take 15 for
the verse, play vocal take 3 for the chorus, and so on.
In other words, you can associate several virtual tracks, or takes,
with a single “real” track. You might play 8 tracks at once, and you can
choose which virtual track (take) plays on each track. For example, you
can record several takes of a guitar solo—keeping each one—and choose
the best take during mixdown. You also can create a composite track,
which is made of the best parts of several takes. All HD recorder-mixers
let you record virtual tracks.
MiniDisc Recorder-Mixer
Introduced by Sony in 1991, the MiniDisc (MD) is a convenient recording medium that is removable, low cost, and near-CD quality. A MiniDisc
recorder-mixer is a multitrack MD recorder and mixer in a single, affordable package. It records and plays 4 or 8 audio tracks at once on a durable,
removable MD data disc. About the size of a floppy disk, an MD data
disc records 8 tracks for 18.5 minutes or 4 tracks for 37 minutes. A MiniDisc costs about $2.00. The built-in mixer has faders and knobs and
includes a small LED screen for nongraphical editing.
Below are some MiniDisc editing features:
•
•
•
•
•
Write disc title and track title on the disc.
Song Copy duplicates a song at a new location.
Song Erase deletes a song.
Track Copy copies data from one track to another.
Song Divide lets you divide a song in two at the current counter
location. With this function, you can create sections—verse, chorus,
etc.—that you can play or repeat in any order. You can also remove
noises before and after songs.
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Practical Recording Techniques
• Song Combine joins divided parts from the same song.
• Time slipping moves individual tracks in time.
• Cue List is a list of the song sections in the order you want them
played. Sections can be looped or repeated. The recorder will play
down the cue list, assembling the song from its sections.
• Program Play List is a list of the songs in the order you want them
played.
• Scale Factor Edit can be used to match the volume of tracks recorded
at different levels, or to create fade-ins and fade-outs.
Pros and Cons of Four Multitrack Recording Systems
Let’s compare a hard-drive recorder, hard-drive recorder-mixer, MiniDisc
recorder-mixer, and computer DAW.
24-Track Hard-Drive Recorder
Pros:
• Portable—great for on-location recording.
• Works with your existing mixer and effects.
• Can export audio data to a computer for editing, or use its own
editing software.
• Stable: Less likely to crash than a computer recording system.
• Might have higher-quality converters than a computer recording
system.
Cons (or comments)
• Requires a mixer, connecting cables, and effects or a computer with
recording software.
• If used with a computer or digital mixer, requires an interface: a
multichannel sound card, USB port, or FireWire port.
• Another hard drive or a DVD-R burner is needed for backup.
Hard-Drive Recorder-Mixer
Pros:
• Easy to use—hands on.
• Simple. No need for a computer, external multitrack recorder, or outboard effects.
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• Portable—good for on-location recording, but bigger than an HD
recorder.
• Less likely to crash than a computer recording system.
• Can export audio data to a computer for editing, or use its own
editing firmware.
• All-in-one system: no external cables needed between recorder and
computer or between mixer and effects.
• Low-cost CD backup.
• Automated mixing.
Cons:
• Less portable than an HD recorder for on-location recording.
• If you already have a mixer or recording software, it may be more
than you need.
• Less flexible than recording software. Not as upgradable. However,
some recorder-mixers have expansion cards that accept downloadable plug-in effects.
• May require copying data to a computer for sophisticated editing
and plug-ins.
Mini-Disc Recorder-Mixer
Pros:
• Once you are done with a project, you simply remove the MiniDisc
and put in a blank one for the next project.
• Low-cost medium.
Cons:
• ATRAC data compression reduces sound quality.
• Not for long recordings (18.5 minutes for 8 tracks on one MiniDisc).
• Can’t transfer tracks to a computer for editing.
Computer Recording System (DAW)
Pros:
• Can be low cost if you already have a fast computer (except for the
top-level [Pro Tools] systems).
• Flexible (due to software upgrades and plug-ins).
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Practical Recording Techniques
• All-in-one system: no external cables between recorder and computer or between mixer and effects.
• Low-cost CD backup.
• Automated mixing.
• Sophisticated editing.
• Can be used with existing analog or digital mixer.
• Saves time if used for recording: multitrack recordings and mixes do
not need to be copied to computer for editing/mastering.
Cons:
• Computer may crash.
• Harder to use than a hardware mixer, but a controller surface can
help with this.
• Not easily portable except in 2-track laptop systems, but could
be used with an HD recorder or recorder-mixer for on-location
recordings.
• Requires a fast computer with a large hard drive optimized for
digital audio.
• Requires strong computer skills (but this is a plus for some users).
• Requires an interface to get audio into and out of the computer. The
interface can be one of these types:
Sound card (2-channel or multichannel)
Alesis ADAT Lightpipe card or Tascam TDIF card
I/O interface (MOTU, M-Audio)
Controller with I/O (Tascam, Edirol, etc.)
Alesis Fireport
Backup
So far we’ve looked at several types of digital recording devices. With
any device, it’s important to back up or make a copy of your recordings’
wave files. The hard drive on which you store your projects will eventually crash. DAT tapes and video tapes have a limited life span as well. So
it’s vital to back up your data periodically.
Some backup systems are CD-R, CD-RW, hard drive (internal or
external FireWire), Iomega Zip drive (100 MB), Jaz drive (2 GB), DVD-
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RAM, and DVD-RW. CD and DVD are perhaps the most long-lasting
formats for archiving. Some engineers prefer to archive audio programs
on analog tape as well as digital.
As we’ve seen, there is a wide variety of digital recording formats.
Learn all you can about digital technology, then choose the formats that
meet your needs.
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10
EFFECTS AND SIGNAL
PROCESSORS
With effects, your mix sounds more like a real “production” and less like
a bland home recording. You might simulate a concert hall with reverb.
Put a guitar in space with stereo chorus. Make a kick drum punchy by
adding compression. Used on all pop-music records, effects can enhance
plain tracks by adding spaciousness and excitement. They are essential if
you want to produce a commercial sound. But many jazz, folk, and classical groups sound fine without any effects.
This chapter describes the most popular signal processors and
effects, and suggests how to use them.
Effects are available both as hardware and software (called plug-ins).
To add a hardware effect to a track, you feed its signal from your mixer’s
aux send to an effects device, or signal processor (Figure 10.1). It modifies the signal in a controlled way. Then the modified signal returns to
your mixer, where it blends with the dry, unprocessed signal.
Software Effects (Plug-Ins)
Most recording programs include plug-ins: software effects that you
control on your computer screen. Each effect is an algorithm (small
program) that runs either in your computer’s CPU or in a DSP card. Some
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Practical Recording Techniques
Figure 10.1
An effects unit.
plug-ins are already installed with the recording software; others can be
downloaded or purchased on CD, then installed on your hard drive. Each
plug-in becomes part of your recording program (called the host), and
can be called up from within the host.
You can use plug-ins made by your recording software company or
by others. Some manufacturers make plug-in bundles, which are a variety
of effects in a single package.
Plug-ins are the usual way to create effects in a DAW. Some DAWs
let you configure your audio interface to produce an aux-send signal,
which you feed to an external hardware processor. The processed signal
returns to the interface and blends with the dry signal.
All the effects described below are available as plug-ins as well as
hardware.
Equalizer
Recall from Chapter 2 that an equalizer (usually in the mixer) is a sophisticated tone control, something like the bass and treble controls in a stereo
system.
Equalization (EQ) lets you improve on reality: add crispness to dull
cymbals or add bite to a wimpy electric guitar. EQ also can make a track
sound more natural; for instance, remove tubbiness from a close-miked
vocal.
To understand how EQ works, we need to know the meaning of a
spectrum. Each instrument or voice produces a wide range of frequencies called its spectrum—the fundamentals and harmonics. The spectrum
gives each instrument its distinctive tone quality or timbre.
If you boost or cut certain frequencies in the spectrum, you change
the tone quality of the recorded instrument. EQ adjusts the bass, treble,
and midrange of a sound by turning up or down certain frequency
ranges. That is, it alters the frequency response. For example, a boost (a
level increase) in the range centered at 10 kHz makes percussion sound
bright and crisp. A cut at the same frequency dulls the sound.
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Types of EQ
Equalizers range from simple to complex. The most basic type is a bass
and treble control (labeled LF EQ and HF EQ). Figure 10.2 shows its effect
on frequency response. Typically, this type has up to 15 dB of boost or cut
at 100 Hz (for the low-frequency EQ knob) and at 10 kHz (for the highfrequency EQ knob).
With a 3-band EQ you can boost or cut the lows, mids, and highs at
fixed frequencies (Figure 10.3). Sweepable EQ is more flexible because
you can “tune in” the exact frequency range needing adjustment (Figure
10.4). If your mixer has sweepable EQ, one knob sets the center frequency
while another sets the amount of boost or cut.
Parametric EQ lets you set the frequency, amount of boost/cut, and
bandwidth—the range of frequencies affected. Figure 10.5 shows how
a parametric equalizer varies the bandwidth of the boosted part of the
Figure 10.2
The effect of the bass and treble control.
Figure 10.3
The effect of 3-band equalization.
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Practical Recording Techniques
Figure 10.4
The effect of sweepable equalization.
Figure 10.5
equalizer.
Curves that illustrate varying the bandwidth of a parametric
spectrum. The “Q” or quality factor of an equalizer is the center frequency
divided by the bandwidth. A boost or cut with a low-Q setting affects a
wide range of frequencies; a high-Q setting makes a narrow peak or dip.
A graphic equalizer (Figure 10.6) is usually outside the mixing
console. This type has a row of slide pots that work on 5 to 31 frequency
bands. When the controls are adjusted, their positions graphically show
the resulting frequency response. Usually, a graphic equalizer is used for
monitor-speaker EQ, or is patched into a channel for sophisticated tonal
tweaking.
Equalizers can also be classified by the shape of their frequency
response. Peaking EQ shapes the response like a hill or peak when set for
a boost (Figure 10.7). With shelving EQ, the shape of the frequency
response resembles a shelf (Figure 10.8). CD track 27 demonstrates various
types of EQ.
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Effects and Signal Processors
Figure 10.6
A graphic equalizer.
Figure 10.7
Peaking equalization at 7 kHz.
Figure 10.8
Shelving equalization at 7 kHz.
10
A filter causes a rolloff at the frequency extremes. It sharply rejects
(attenuates) frequencies above or below a certain frequency. Figure 10.9
shows three types of filters: lowpass, highpass, and bandpass. For
example, a 10-kHz lowpass filter (high-cut filter) removes frequencies
above 10 kHz. Its response is down 3 dB at 10 kHz and more above that.
This reduces hiss-type noise without affecting tone quality as much as a
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Practical Recording Techniques
Figure 10.9
Lowpass, highpass, and bandpass filters.
gradual treble rolloff would. A 100-Hz highpass filter (low-cut filter)
attenuates frequencies below 100 Hz. Its response is down 3 dB at 100 Hz
and more below that. This removes low-pitched noises such as air
handler rumble or breath pops. A 1-kHz bandpass filter cuts frequencies
above and below a frequency band centered at 1 kHz.
The crossover filter in some monitor speakers consists of lowpass,
highpass, and bandpass filters. They send the lows to the woofer, mids
to the midrange, and highs to the tweeter.
A filter is named for the steepness of its rolloff: 6 dB per octave (first
order), 12 dB per octave (second order), 18 dB per octave (third order),
and so on.
How to Use EQ
If your mixer has bass and treble controls, their frequencies are preset
(usually at 100 Hz and 10 kHz). Set the EQ knob at 0 to have no effect (flat
setting). Turn it clockwise for a boost; turn it counterclockwise for a cut.
If your mixer has multiple-frequency EQ or sweepable EQ, one knob sets
the frequency range and another sets the amount of boost or cut.
Table 10.1 shows the fundamentals and harmonics of musical instruments and voices. The harmonics given represent an approximate range.
For each instrument, turn up the lower end of the fundamentals to get
warmth and fullness. Turn down the fundamentals if the tone is too bassy
or tubby. Turn up the harmonics for presence and definition; turn down
the harmonics if the tone is too harsh or sizzly.
Percussion, cymbals, and muted trumpet actually have some energy
up to 80 to 100 kHz.
Here are some suggested frequencies to adjust for specific instruments. If you want the effects described below, apply boost. If you don’t,
apply cut. Try these suggestions and accept only the sounds you like:
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Table 10.1 Frequency Ranges of Musical
Instruments and Voices
Instrument
Fundamentals
Harmonics
Flute
Oboe
Clarinet
Bassoon
Trumpet
French horn
Trombone
Tuba
Snare drum
Kick drum
Cymbals
Violin
Viola
Cello
Acoustic bass
Electric bass
Acoustic guitar
Electric guitar
Elec. guitar amp
Piano
Bass (voice)
Tenor (voice)
Alto (voice)
Soprano (voice)
261–2349 Hz
261–1568 Hz
165–1568 Hz
62–587 Hz
165–988 Hz
87–880 Hz
73–587 Hz
49–587 Hz
100–200 Hz
30–147 Hz
300–587 Hz
196–3136 Hz
131–1175 Hz
65–698 Hz
41–294 Hz
41–294 Hz
82–988 Hz
82–1319 Hz
82–1319 Hz
28–4196 Hz
87–392 Hz
131–494 Hz
175–698 Hz
247–1175 Hz
3–8 kHz
2–12 kHz
2–10 kHz
1–7 kHz
1–7.5 kHz
1–6 kHz
1–7.5 kHz
1–4 kHz
1–20 kHz
1–6 kHz
1–15 kHz
4–15 kHz
2–8.5 kHz
1–6.5 kHz
700 Hz–5 kHz
700 Hz–7 kHz
1500 Hz–15 kHz
1–15 kHz (direct)
1–4 kHz
5–8 kHz
1–12 kHz
1–12 kHz
2–12 kHz
2–12 kHz
• Bass: Full and deep at 60 Hz, growl at 600 Hz, presence at 2.5 kHz,
string noise at 3 kHz and up.
• Electric guitar: Thumpy at 60 Hz, full at 100 Hz, puffy at 500 Hz, presence or bite at 2 to 3 kHz, sizzly and raspy above 6 kHz.
• Drums: Full at 100 Hz, wooly at 250 to 600 Hz, trashy at 1 to 3 kHz,
attack at 5 kHz, sizzly and crisp at 10 kHz.
• Kick drum: Full and powerful below 60 Hz, papery at 300 to 800 Hz
(cut at 400 to 600 Hz for better tone), click or attack at 2 to 6 kHz.
• Sax: Warm at 500 Hz, harsh at 3 kHz, key noise above 10 kHz.
• Acoustic guitar: Full or thumpy at 80 Hz, presence at 5 kHz, pick
noise above 10 kHz.
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• Voice: Full at 100 to 150 Hz (males), full at 200 to 250 Hz (females),
honky or nasal at 500 Hz to 1 kHz, presence at 5 kHz, sibilance (“s”
sounds) above 6 kHz.
• Example: Suppose a vocal track sounds too full or bassy. Reach for
the LF EQ knob (say, 100 Hz) and turn it down until the voice sounds
natural. To reduce muddiness on snare, bass, electric guitar, or vocal,
cut around 300 Hz.
Set EQ to the approximate frequency range you need to work on. Then
apply full boost or cut so the effect is easily audible. Finally, fine-tune the
frequency and amount of boost or cut until the tonal balance is the way
you like it.
What if an instrument sounds honky, tubby, or harsh, and you
don’t know what frequency to tweak? Set a sweepable equalizer for
extreme boost. Then sweep the frequencies until you find the frequency range matching the coloration. Cut that range by the amount that
sounds right. For example, a piano miked with the lid closed might have
a tubby coloration—maybe too much output around 300 Hz. Set your
low-frequency EQ for boost, and vary the center frequency until the tubbiness is exaggerated. Then cut at that frequency until the piano sounds
natural.
In general, avoid excessive boost because it can distort the signal.
Try cutting the lows instead of boosting the highs. To reduce muddiness
or enhance clarity, cut 1 to 2 dB around 300 Hz—either on individual
instruments or on the entire mix. Don’t boost everything at the same
frequency.
When to Use EQ
Before using EQ, try to get the desired tone quality by changing the
mic or its placement. This gives a more natural effect than EQ. Many
purists shun the use of EQ, complaining of excessive phase shift or
ringing caused by the equalizer—a “strained” sound. Instead, they use
carefully placed, high-quality microphones to get a natural tonal balance
without EQ.
Suppose you still need some EQ. Should you EQ while recording or
mixing? If you mix more than one instrument to the same track, you can’t
EQ them independently during mixdown unless their frequency ranges
are far apart. To explain, suppose a recorded track contains lead guitar
and vocals. If you add a midrange boost to the guitar, you’ll hear it on
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the vocals, too. The only solution is to EQ the lead guitar by itself when
you record it.
If you assign each instrument to its own track, the usual practice is
to record flat (without EQ) and then equalize the track during mixdown.
Sometimes the instruments need a lot of EQ to sound good. If so,
you might want to record with EQ so that the playback for the musicians
will sound good. When you play the multitrack recording through your
monitor mixer, the recording may not sound right unless the tracks are
already equalized. (That’s assuming the monitor mixer in your board has
no EQ.)
When you do a bass cut or treble boost, you’ll get a better signal-tonoise (S/N) ratio by applying this EQ during recording, instead of during
mixdown. But if you’re doing a treble cut, apply it during mixdown to
reduce any hiss.
Uses of EQ
Here are some applications for EQ:
• Improve tone quality. The main use for EQ is to make an instrument
sound better tonally. For example, you might use a high-frequency
rolloff on a singer to reduce sibilance, or on a direct-recorded electric guitar to take the “edge” off the sound. You could boost 100 Hz
on a floor tom to get a fuller sound, or cut around 250 Hz on a bass
guitar for clarity. Cut around 100 Hz to reduce bass buildup on
massed harmony vocals. The frequency response and placement of
each mic affect tone quality as well.
Although you can set the EQ for each track when it is soloed, a better
way is to set the equalizers when the entire mix is playing. That’s because
one instrument can mask or hide certain frequencies in another instrument. For example, the cymbals might mask the “s” sounds in the vocal,
making the vocal sound dull—even though it might sound fine when
soloed.
• Create an effect. Extreme EQ reduces fidelity, but it also can make
interesting sound effects. Sharply rolling off the lows and highs on
a voice, for instance, gives it a “telephone” sound. A 1-kHz bandpass filter does the same thing. To make a mono keyboard track
sound stereo, send it to two mixer channels. Boost lows and cut
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Practical Recording Techniques
highs in one channel panned left; cut lows and boost highs in the
other channel panned right.
• Reduce noise and leakage. You can reduce low-frequency noises—
bass leakage, air-conditioner rumble, mic-stand thumps—by
turning down the lows below the range of the instrument you’re
recording.
For example, a fiddle’s lowest frequency is about 200 Hz, so you’d use a
low-cut filter (highpass filter) set to 200 Hz (if possible). This low-cut filter
won’t change the fiddle’s tone quality because the filtered-out frequencies are below the fiddle’s lowest frequency. Similarly, a kick drum has
little or no output above 9 kHz, so you can filter out highs above 9 kHz
on the kick drum to reduce cymbal leakage. Filtering out frequencies
below 100 Hz on most instruments reduces air-conditioning rumble and
breath pops. Try rolling off the lows on audience mics to prevent muddy
bass. To reduce hum, set a parametric EQ for a 24-dB cut, Q of 30, at these
frequencies: 60, 120, and 180 Hz (in the United States) or 50 100 Hz, and
150 Hz (in Europe).
• Compensate for the Fletcher-Munson effect. As discovered by
Fletcher and Munson, the ear is less sensitive to bass and treble at
low volumes than at high volumes. So, when you record a very loud
instrument and play it back at a lower level, it might lack bass and
treble. To restore these, you may need to boost the lows (around
100 Hz) and the highs (around 4 kHz) when recording loud rock
groups. The louder the group, the more boost you need. It also helps
to use cardioid mics with proximity effect (for bass boost) and a presence peak (for treble boost).
• Make a pleasing blend. If you mix two instruments that sound alike,
such as lead guitar and rhythm guitar, they tend to mush together—
it’s hard to tell what each is playing. You can make them more distinct by equalizing them differently. For example, make the lead
guitar edgy by boosting 3 kHz, and make the rhythm guitar mellow
by cutting 3 kHz. Then you’ll hear a more pleasing blend and a
clearer mix. The same philosophy applies to bass guitar and kick
drum. Because they occupy about the same low-frequency range,
they tend to mask or cover each other. To make them distinct, either
fatten the bass and thin out the kick a little, or vice versa. The idea
is to give each instrument its own space in the frequency spectrum;
for example, the bass fills in the lows, synth chords emphasize mid-
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Effects and Signal Processors
10
bass, lead guitar adds edge in the upper mids, and cymbals add
sparkle in the highs.
• Compensate for mic placement. Sometimes you are forced to mike
very close to reject background sounds and leakage. But a close mic
emphasizes the part of the instrument that the mic is near. This gives
a colored tone quality, but EQ can partly compensate for it. Suppose
you had to record an acoustic guitar with a mic near the sound hole.
The guitar track will sound bassy because the sound hole radiates
strong low frequencies. But you can turn down the lows on your
mixer to restore a natural tonal balance.
This use of EQ can save the day by fixing poorly recorded tracks in live
concert recordings. During a concert, the stage monitors might be blaring
into your recording/PA microphones, so you’re forced to mike close in
order to reject monitor leakage and feedback. This close placement, or the
monitor leakage itself, can give the recording an unnatural tone quality.
In this case, EQ is the only way to get usable tracks.
• Re-mix” a single track. If a track contains two different instruments,
sometimes you can change the mix within that track by using EQ.
Imagine a track that has both bass and synth. By using LF EQ, you
can bring the bass up or down without affecting the synth very
much. Mixing with EQ is more effective when the two instruments
are far apart in their frequency ranges.
Whenever you record, the ideal situation is to use the right mic in the
right position, and in a good-sounding room. Then you don’t need or
want equalization. Otherwise, though, your recordings will sound better
with EQ than without it.
Compressor
A compressor acts like an automatic volume control, turning down the
volume when the signal gets too loud. Here’s why it’s necessary.
Suppose you’re recording a female vocalist. Sometimes she sings too
softly and gets buried in the mix; other times she hits loud notes, blasting the listener and saturating the tape. Or she may move toward and
away from the mic while singing, so that her average recording level
changes.
To control this problem, you can ride gain—turn her down when
she gets too loud; turn her up when she gets too quiet. But it’s hard to
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Practical Recording Techniques
anticipate these changes. You might prefer to use a compressor, which
does the same thing automatically. It reduces the gain (amplification)
when the input signal exceeds a preset level (called the threshold). The
greater the input level, the less the gain. As a result, loud notes are made
softer, so the dynamic range is reduced (Figure 10.10). Play CD track 28.
Compression keeps the level of vocals or instruments more constant,
so they are easier to hear throughout the mix, and it prevents loud notes
that might clip. Also, it can be used for special effects—to make drums
sound fatter, or to increase the sustain on a bass guitar. In pro studios,
compression is used almost always on vocals; often on bass guitar, kick
drum, and acoustic guitar; and sometimes on other instruments.
Doesn’t compression rob the music of its expressive dynamics? Yes,
if overdone. But a vocal that gets too loud and soft is annoying. You need
to tame it with a compressor. Even then, you can tell when the vocalist
is singing loudly by the tone of the voice. It also helps to compress the
bass and kick drum to ensure a uniform, driving beat.
You can avoid vocal compression if the singer uses proper mic technique. He or she should back away from the mic on loud notes, and come
in close on soft notes. To tell whether you need a compressor, listen to
your finished mix. If you can understand all the words, and no notes are
too loud, omit the compressor.
Using a Compressor
Normally, you compress individual tracks or instruments, not the
entire mix. You want to compress only the stuff that needs it. To compress a stereo mix, you need a 2-channel compressor with a stereo
link, which keeps the left–right balance from changing. Multiband compression (covered later) is usually a better choice for compressing the
stereo mix.
Figure 10.10
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Compression.
Effects and Signal Processors
10
Should you compress while tracking or mixing? If you compress
while tracking, it will be difficult or impossible to change the amount of
compression during mixdown. If you compress tracks during mixdown,
you can change the settings at will.
Apply EQ before you compress. Often there is too much bass on a
track, and that extra bass will trigger the compressor unless you EQ it
out first.
Let’s describe the controls on the compressor. Some compressors
have few controls; most of their settings are preset at the factory.
Compression Ratio or Slope
This is the ratio of the change in input level to the change in output level.
For example, a 2 : 1 ratio means that for every 2 dB change in input level,
the output changes 1 dB. A 20 dB change in input level results in a 10 dB
change in the output, and so on.
Typical ratio settings are 2 : 1 to 4 : 1. A “soft knee” or “over easy”
characteristic is a low compression ratio for low-level signals and a high
ratio for high-level signals. Some manufacturers say that this characteristic sounds more natural than a fixed compression ratio.
Threshold
This is the input level above which compression occurs. Set the threshold high (about -5 dB) to compress only the loudest notes; set it low (-10
or -20 dB) to compress a broader range of notes. A setting of -10 is typical.
If the compressor has a fixed threshold, adjust the amount of compression with the input level control.
Many compressor plug-ins display a compression-ratio graph that
shows input level on the horizontal axis and output level on the vertical
axis. If the compression ratio is 1 : 1 (no compression), the graph is a diagonal straight line. This line bends to the right above the threshold, where
the compression ratio increases to the amount that you set.
Gain Reduction
This is the number of dB that the gain is reduced by the compressor. It
varies with the input level. You set the ratio and threshold controls so
that the gain is reduced on loud notes by an amount that sounds right.
The amount of gain reduction shows up on a meter—3 to 10 dB is typical.
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Practical Recording Techniques
Attack Time
This is how fast the compressor reduces the gain when it’s hit by a
musical attack. Typical attack times range from 0.25 to 10 msec. Some
compressors adjust the attack time automatically to suit the music; others
have a factory-set attack time. The longer the attack time, the larger the
peaks that are passed before gain reduction occurs. So, a long attack time
sounds punchy; a short attack time reduces punch by softening the attack.
Release Time
This is how fast the gain returns to normal after a loud passage ends.
It’s the time the compressor takes to reach 63% of its normal gain.
You can set the release time from about 50 msec to several seconds.
One-half second to 0.2 seconds is typical. For bass instruments, the
release time must be longer than about 0.4 seconds to prevent harmonic
distortion.
Short release times make the compressor follow rapid volume
changes in the music, and keep the average level higher. But because the
noise rises along with the gain, short release times can give a pumping
or breathing sound. Long release times sound more natural. If the release
time is too long, though, a loud passage will reduce the gain during a
subsequent quiet passage. In some units, the release time varies automatically, or is factory-set to a useful value.
Some compressors disable the attack and release settings when the
compressor is set to RMS or average mode. Those settings are adjusted
automatically.
Output-Level Control
Also called make-up gain, this control is used to increase the output level
of the compressor by the amount of gain reduction. For example, if a compressor is causing 6 dB of level reduction, increase the make-up gain by
6 dB to achieve unity gain. Some compressors keep the output level constant when other controls are varied.
Spend some free time playing with all the settings so you learn how
they affect the sound. Play various instruments and vocals through a
compressor, vary the settings, and take notes on what you hear.
Some compressors have a side chain. This is a pair of in/out jacks
for connecting an equalizer. To compress only the sibilant sounds on a
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vocal track, boost the side-chain EQ around 10 kHz. To compress only the
breath pops on a vocal track, boost the side-chain EQ around 20 Hz.
A multiband or split-frequency compressor divides the audio band
into three or four bands (bass, mids, treble) and compresses each band
separately. That way, the compressor can squash a loud bass note, or
soften “s” sounds, without bringing down the overall level. Multiband
compression is often applied to the final mix of each song during
mixdown or mastering.
Connecting a Compressor
Connect a compressor in line with the signal you want to compress, in
one of the following ways:
• To compress one instrument or voice while recording: Locate the
input module of the instrument you want to compress. On the back
of that module, connect the insert send jack to compressor in;
connect compressor out to the insert return jack. (Chapter 11
explains these terms.) Or, take a signal from the input module’s
direct out. Feed that into the compressor, and feed the compressor
output to the recorder track input.
• To compress a group of instruments while recording: Locate the bus
output of the instruments you want to compress. Go from bus out
to compressor in, and go from compressor out to recorder-track in.
If the bus has insert jacks, you could connect to them instead.
• To compress one track during mixdown: Go from track out to compressor in, and go from compressor out to mixer channel in. Or
locate the mixer input module for that track, then find the insert send
and return jacks in that module. (There might be a single Insert jack
with send and return terminals.) Connect the insert send to compressor in; connect compressor out to insert return.
• To compress one track in DAW, select a compressor plug-in for that
track. Do not use an aux send for compression.
Suggested “Ballpark” Compressor Settings
• Vocals: Ratio 2 : 1 to 3 : 1, fast attack, 1/2 second release, set threshold for 3 to 6 dB of gain reduction. Singers with extreme dynamic
range might need 12 dB of gain reduction and a ratio of 4 : 1.
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Practical Recording Techniques
• Bass and drums: Ratio 4 : 1, slow attack, slow release, set threshold
for 3 to 6 dB of gain reduction on loud “pops.” Adjust attack time
depending on how much you want to soften the attack. Short attack
time = soft attack, long attack time = loud attack.
• Electric guitar: 4 : 1 to 8 : 1 ratio, 10-dB gain reduction, 400 msec
release.
• To reduce breath pops: Use a multiband compressor. Enable only
the lowest frequency band. Try these settings: ratio 30 : 1, upper frequency 600 Hz, make-up gain 0 dB, attack 1 msec, release 100 msec,
threshold -18 dB. Experiment with the threshold setting.
• To reduce sibilance: Use a multiband compressor. Disable all bands
except the upper-midrange. Try these settings: ratio 20 : 1, make-up
gain 2 dB, attack 1 msec, release 100 msec, hi-mid 5 kHz, high 5 kHz,
threshold -32 dB. Experiment with the threshold setting.
• To compress the stereo mix: Try these settings: 2 : 1, soft knee, attack
20 msec, release 200 msec. Set the threshold to get 5 to 10 dB of gain
reduction.
Limiter
A limiter keeps signal peaks from exceeding a preset level. While a compressor reduces the overall dynamic range of the music, a limiter affects
only the highest peaks (Figure 10.11). To act on these rapid peaks,
limiters have a very fast attack time—1 microsecond to 1 millisecond. The
compression ratio in a limiter is very high—10 : 1 or greater—and the
threshold is set high, say at 0 dB. For input levels up to 0 dB, the output
level matches the input. For input levels above 0 dB, the output level stays
at 0 dB. This prevents overload in the device following the limiter
A compressor/limiter carries out both of the functions in its name.
It compresses the average signal levels over a wide range, and limits
Figure 10.11
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Limiting.
Effects and Signal Processors
10
peaks to prevent overload. It has two thresholds: one low for the compressor and one high for the limiter.
Limiters can be used to prevent recorder overload during field
recording, or to prevent PA power amps from clipping. When you master
a program of several mixed songs in a DAW, you might use limiting to
reduce the level of signal peaks in the program. Set the threshold about
6 dB below the highest peak level. Then apply normalization, which raises
the level of the entire program until the highest peak in the program
reaches maximum level. Limiting and normalization create a louder
program on your finished CD without compressing the music’s
dynamics.
Noise Gate
A noise gate (expander) acts like an on-off switch that removes noises
during pauses in an audio signal. It reduces the gain when the input level
falls below a preset threshold. That is, when an instrument stops playing
for a moment, the noise gate drops the volume, which removes any noise
and leakage during the pause (Figure 10.12).
Note: The gate does not remove noise while the instrument is
playing.
Where is it used? The noise gate helps to clean up drum tracks by
removing leakage between beats. It can shorten the decay time of the
drums, giving a very tight sound. If you’re recording a noisy guitar amp,
try a gate to cut out the buzz and hiss between phrases.
How do you use a noise gate? Patch it between a recorder-track
output and a mixer line input, or use a gate plug-in in a DAW. Solo the
track that you want to gate. Set the gate’s threshold so that noise and
leakage go away during pauses. If the gate chops off each note, the threshold is set too high—turn it down. To fix a boomy kick drum, adjust the
threshold until the kick sounds as “tight” as you want. That is, use the
Figure 10.12
Gating.
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Practical Recording Techniques
gate to shorten the decay portion of the kick-drum’s envelope. Set the
release time short for drums and longer for instruments that have a long
sustain.
Excellent recordings can be made without gating. But if you want a
tighter sound, gates come in handy. Some signal processors have compression, limiting, and noise gating in a single package.
Some gates have a side-chain input or key input. It’s an input for an
external signal that controls the gating action. The control signal triggers
the output of the gate’s main audio path. For example, you could feed a
bass guitar through the noise gate, and gate the bass with a kick-drum
signal fed into the side chain. Then the bass will follow the kick drum’s
envelope.
Delay: Echo, Doubling, Chorus, and Flanging
A digital delay (or a delay plug-in) takes an input signal, holds it in a
memory chip, then plays it back after a short delay—about 1 msec to 1
second (Figure 10.13). Delay is the time interval between the input signal
and its repetition at the output of the delay device.
If you listen to the delayed signal by itself, it sounds the same as the
undelayed (dry) signal. But if you combine the delayed and dry signals,
you may hear two distinct sounds: the signal and its repetition. By delaying a signal, a processor can create several effects such as echo, repeating
echo, doubling, chorus, and flanging.
Echo
If the delay is about 50 msec to 1 second, the delayed repetition of a sound
is called an echo. This is shown in Figure 10.14 by the two pulses. Echoes
occur naturally when sound waves travel to a distant room surface,
bounce off, and return later to the listener—repeating the original sound.
Figure 10.13
218
Delaying the signal.
Effects and Signal Processors
Figure 10.14
10
Echo.
A delay unit can mimic this effect. Many people use the term delay to
mean echo.
In setting up a mix with echo, you want to hear both the dry sound
and its echo. You do this by creating an effects loop: from the mixer, to
the effects box, back to the mixer. Here’s how:
1. On the delay unit, set the dry/wet mix control all the way to “wet”
or “100% mix.” Then the output of the delay unit will be only the
delayed signal.
2. Suppose you want to use aux1 as the echo control. Connect aux1
send to delay unit IN. Connect delay unit OUT to Bus 1 and 2 IN
(or to the effects-return jacks).
3. Find the mixer module for the instrument you want to add echo to.
4. Assign the instrument to busses 1 and 2. Monitor busses 1 and 2.
5. Find the knobs labeled Bus 1 IN and Bus 2 IN. They might be called
“Aux Return” or “Effects Return.” Turn them up to 0, about threefourths of the way up.
6. Turn up the aux1 send knob, and there’s your echo.
The delayed sound mixes with the dry sound in busses 1 and 2. You hear
both sounds, which together make an echo. Each aux knob controls the
amount of echo on each track, while the effect-return knobs control the
overall amount of echo on all tracks that are feeding the echo unit.
To set up echo in a DAW, follow this procedure:
1. Create or use a stereo aux bus that has an Echo or Delay plug-in
enabled.
2. On a track that you want to have echo, enable and turn up the virtual
aux-send knob.
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3. Open the Echo or Delay plug-in. Set its dry/wet mix control all the
way to wet or 100% mix. Adjust the parameters for the desired effect.
Slap Echo
A delay from 50 to 200 msec is called a slap echo or slapback echo. It was
often used in 1950s rock ‘n’ roll tunes, and still is used today.
Repeating Echo
Most delay units can be made to feed the output signal back into the
input, internally. Then the signal is re-delayed many times. This creates
a repeating echo—several echoes that are evenly spaced in time (Figure
10.15, and CD tracks 29 and 30). The regeneration (feedback) control sets
the number of repeats.
Repeating echo is most musical if you set the delay time to create an
echo rhythm that fits the tempo of the song. The formula is
Delay in seconds 60/tempo
So if the tempo is 120 bpm, the delay is 0.5 sec (500 msec). That’s one echo
per quarter note. Use half that delay to get one echo per eighth note. Use
one-third that delay for triplets. A slow repeating echo—0.5 second
between repeats, for example—gives an outer-space or haunted-house
effect.
Doubling
If you set the delay around 30 to 60 msec, the effect is called doubling or
automatic double tracking (ADT). It gives an instrument or voice a fuller
sound, especially if the dry and delayed signals are panned to opposite
sides. The short delays used in doubling sound like early sound reflections in a studio, so they add some “air” or ambience.
Figure 10.15
220
Repeating echo.
Effects and Signal Processors
10
Doubling a vocal can be done without a delay unit. Record a vocal
part, then overdub another performance of the same vocal part. Mix the
parts, pan them both to center, or pan them left and right.
Chorus
This is a wavy or shimmering effect. The delay is 15 to 35 msec, and the
delay varies at a slow rate. Sweeping the delay time causes the delayed
signal to bend up and down in pitch, or to detune. When you combine
the detuned signal with the original signal, you get chorusing.
Stereo Chorus
This is a beautiful effect. In one channel, the delayed signal is combined
with the dry signal in the same polarity. In the other channel, the delayed
signal is inverted in polarity, then combined with the dry signal. Thus,
the right channel has a series of peaks in the frequency response where
the left channel has dips, and vice versa. The delay is slowly varied or
modulated. Hear a demonstration on CD track 33.
Bass Chorus
This is chorus with a high-pass filter so that low frequencies are not chorused, but higher harmonics are. It gives an ethereal quality to the bass
guitar.
Flanging
If you set the delay around 0 to 20 msec, you usually can’t resolve
the direct and delayed signals into two separate sounds. Instead, you
hear a single sound with a strange frequency response. The direct
and delayed signals combine and have phase interference, which puts a
series of peaks and dips in the frequency response. This is called a combfilter effect (Figure 10.16). It gives a very colored, filtered tone quality. The
shorter the delay, the farther apart the peaks and dips are spaced in
frequency.
The flanging effect varies or sweeps the delay between about 0 and
20 msec. This makes the comb-filter nulls sweep up and down the spectrum. As a result, the sound is hollow, swishing, and ethereal, as if the
music were playing through a pipe. Flanging is easiest to hear with
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Practical Recording Techniques
broadband signals such as cymbals but can be used on any instrument,
even voices. Hear a demonstration on CD track 34.
Some examples of flanging are on many Jimi Hendrix records, and
on the oldies “Itchycoo Park” by the Small Faces and “Listen to the
Music” by the Doobie Brothers. The first use of flanging was on “The Big
Hurt” sung by Toni Fisher.
Positive flanging refers to flanging in which the delayed signal is the
same polarity as the direct signal (Figure 10.16). With negative flanging,
the delayed signal is opposite in polarity to the direct signal, which makes
a stronger effect. The low frequencies are canceled (the bass rolls off), and
the “knee” of the bass rolloff moves up and down the spectrum as the
delay is varied. The high frequencies are still comb-filtered (Figure 10.17).
Negative flanging makes the music sound like it’s turning inside out.
When the flanger feeds some of the output signal back into the input,
the peaks and dips get bigger. It’s a powerful “science fiction” effect
called resonant flanging.
Reverberation
This effect adds a sense of room acoustics, ambience, or space to instruments and voices. To know how it works, we need to understand how
222
Figure 10.16
Flanging (or positive flanging).
Figure 10.17
Negative flanging.
Effects and Signal Processors
10
reverb happens in a real room. Natural reverberation in a room is a series
of multiple sound reflections that make the original sound persist and
gradually die away or decay. These reflections tell the ear that you’re listening in a large or hard-surfaced room. For example, reverberation is the
sound you hear just after you shout in an empty gymnasium.
A reverb effect simulates the sound of a room—a club, auditorium,
or concert hall—by generating random multiple echoes that are too
numerous and rapid for the ear to resolve (Figure 10.18). Digital reverb
is available either in a dedicated reverb unit, as part of a multi-effects
processor, or as a plug-in.
The most natural sounding digital reverb is a sampling reverb or
convolution reverb, which creates the reverb from impulse-response
samples (wave files) of real acoustic spaces, rather than from algorithms.
One convolution reverb plug-in is SIR at www.knufinke.de/
sir/index_en.html. Free impulse-response samples are at www.
noisevault.com and www.echochamber.ch.
Reverb and echo are not the same thing. Echo is a repetition of a
sound (HELLO hello hello); reverb is a smooth decay of sound (HELLOOO-oo-oo).
Multichannel digital reverbs are available for surround sound, both
as hardware and software. Some examples are Eventide’s Orville, Sony’s
DRE-S777, TC Electronics’ System 6000, Lexicon’s 960L, and Kind of
Loud’s RealVerb 5.1 Pro Tools plug-in. Surround reverb plug-ins for
Steinberg’s Nuendo platform include Steinberg’s Surround Edition plugin bundle and TC Works SurroundVerb plug-in.
Reverb Parameters
Here are some controls in a reverb unit or plug-in:
• Reverb Time (RT60): The time it takes for reverberation to decay
60 dB below its original level. Set it long (1 1/2 to 2 seconds) to
Figure 10.18
Reverberation.
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Practical Recording Techniques
•
•
•
•
simulate a large room; set it short (under 1 second) to simulate a
small room. Generally you use short reverbs (or no reverb) for fast
songs, and long reverbs for slow songs.
Pre-delay (pre-reverb delay): A short delay (30 to 100 msec) before
the onset of reverb to simulate the delay that happens in real rooms
before reverb starts. The longer the pre-delay, the bigger the room
sounds. Using pre-delay on an instrument’s reverb often helps to
clarify the sound by removing the onset of reverb from the direct
sound of the instrument. If your reverb unit does not have pre-delay
built in, you can create it by connecting a delay unit between your
mixer’s aux-send and the reverb input. CD track 31 demonstrates
reverb: short reverb time, long reverb time, and pre-delay.
Density: A high density setting produces many echoes spaced close
together. It gives a smooth decay but increases the load on the CPU.
A low-density setting produces fewer echoes spaced farther apart,
and may be adequate for vocals.
Damping: Adjusts the reverb time or decay at high frequencies. Set
the damping frequency high (say, 10 kHz) to simulate a hardsurfaced room; set it low (say, 2 kHz) to simulate a soft-surfaced
room. The latter is also called a “warm room” reverb.
Presets: Algorithms or small programs that simulate the reverb patterns of small rooms, auditoriums, halls, and so on. A plate reverb
setting duplicates the bright sound of a metal-foil plate, which used
to be the most popular type of reverb in pro studios. Unnatural
effects are available, such as nonlinear decay, reverse reverb that
builds up before decaying, or gated reverb. With gated reverb, the
reverb cuts off suddenly shortly after a note is hit. It’s often used on
a snare drum. A good example is the oldie “You Can Call Me Al” on
Paul Simon’s album Graceland.
Reverb Connections
To connect a reverb unit to your mixer, connect a cable from the mixer
aux-send to the reverb input. Connect a cable (two for stereo) from
the reverb outputs to the mixer aux returns (effects returns or bus
inputs). Set the mix control on the reverb unit all the way to “wet”
or “reverb.” Turn the mixer’s aux-return or bus-in knobs (if any) about
two-thirds of the way up, and adjust the amount of reverb on each track
with the aux-send knobs. Try to get an overall reverb-send level near 0
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10
on the meter; then fine-tune the aux return level for the desired amount
of reverb.
To enable reverb in a DAW, use the same procedure as for setting
up echo, but choose a reverb plug-in.
Preverb
Preverb is reverb that precedes a note rather than follows it. The reverb
starts from silence and builds up to a note’s attack (CD track 32). When
used on a snare drum, preverb gives a whip-cracking kind of sound, like
“shSHK!”
Here’s how to add preverb to a snare drum track in a DAW:
1. Set up an aux1 bus with reverb. Set the reverb all the way to wet or
100% mix.
2. Mute all tracks except the drum track.
3. On the drum track, turn up the aux1 send and set it to pre-fader.
4. Turn down the drum-track fader and play the track. You should hear
only the reverb from the aux1 bus.
5. Export or save the mix as “Drum reverb.wav”.
6. Select a blank track and call it Drum Reverb. Import “Drum
reverb.wav” into that track.
7. In the drum-reverb track you just imported, find a good snare hit
with reverb. Make it a clip or region (a selected area) and delete the
rest of the track.
8. Select the drum-reverb clip, then select the Reverse processing in
your DAW. This reverses the drum-reverb clip.
9. On the snare-drum track, disable or turn down the aux1 send. Turn
up the track fader.
10. Slide in time the reversed drum-reverb clip so that it ends just as a
snare-drum hit starts (check the waveforms).
11. Play the reversed drum-reverb track along with the snare-drum
track. You should hear preverb.
Some signal processors have a reverse reverb effect in which the reverb
comes after the note that produced it, but builds up before it fades out.
This is not quite the same as preverb. Reverse reverb can upset the
musical timing; preverb doesn’t.
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Enhancer
If a track or a mix sounds dull and muffled, you can run it through an
enhancer to add brilliance and clarity. An enhancer works either by
adding slight distortion (as in the Aphex Aural Exciter) or by boosting
the treble when the signal has high-frequency content (as in the Alesis
Micro Enhancer and the Barcus Berry Sonic Maximizer).
The latter device also divides the frequency range into three bands.
The lows are delayed about 1.5 msec; the midrange is delayed about
0.5 msec; and the highs are delayed only a few microseconds. In this
way, the Maximizer aligns the harmonics and fundamentals in time for
added clarity.
Octave Divider
This unit takes a signal from a bass guitar and provides deep, growling
bass notes one or two octaves below the pitch of the bass guitar. It does
this by dividing the incoming frequency by 2 or 4: If you put 82 Hz in,
you get 41 Hz out. Some MIDI sound modules have bass patches with
extra-deep sound, and some bass guitars have an extra string tuned especially low.
Harmonizer
Basically a delay unit with delay modulation, a harmonizer makes a
variety of pitch-shifting effects. It can create harmonies, change pitch
without changing the duration of the program, change duration without
changing pitch, and many other oddities. You’ve heard harmonizers on
radio-station spots when the announcer’s voice sounds like a Munchkin
or Darth Vader. Play CD track 35.
Vocal Processor
This device or plug-in can affect the vocal’s inflection, add growls or
whispers, correct the pitch, add vibrato, make the voice more-or-less
nasal or chesty, and so on. The latest vocal formant-corrected pitchshifters maintain the voice formant structure when they shift pitch;
this prevents the “chipmunk” effect. Examples are TC-Helicon
VoicePrismPlus.
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Automatic Pitch Correction
Auto-Tune by Antares provides automatic or manual pitch correction. It
corrects flat or sharp notes by changing their pitch to match a musical
scale of your choice. You also can use Auto-Tune as a “robotic” effect
where the sung notes change pitch in a step-wise, jerky way rather than
smoothly. Pitch-correction plug-ins are available from other companies
as well.
Tube Processor
This device uses a vacuum tube or a transistor simulation of one. Tubes
have euphonic even-order harmonic distortion, which is claimed to add
“richness” or “warmth” when the tube distorts (CD track 36). There are
tube mics, tube mic preamps, tube compressors, and standalone tube
processors.
Rotary Speaker Simulator
This effect simulates the sound of a Leslie organ speaker, which plays
music through rotating horns. It’s a complex sound effect of pitch shifting, tremolo, and phase shifting. The speed and depth of the effect are
adjustable.
Analog Tape Simulator
Analog tape saturation is mainly third-harmonic distortion and compression. An analog tape simulator adds this distortion to digital recordings in an attempt to smear or warm up the sound in a pleasant way (CD
track 37).
Spatial Processor
Spatial processors enhance the stereo imaging or spatial aspects of a mix
heard over two speakers. Some units have joystick-type pan pots, which
move the image of each track anywhere around the listener. Other units
make the stereo stage wider, so that images can be placed to the left of
the left speaker, and to the right of the right speaker. The listener might
hear images toward the sides of the listening room. In 5.1 surround
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Practical Recording Techniques
systems, this spatial processing is done by surround panning and surround reverbs.
Microphone Modeler
Antares and Roland offer a microphone modeler or simulator. You tell it
which mic you are using and which mic you want it to sound like. A wide
variety of vintage and current mic simulations are available. Mic modeling comes in three forms: hardware device, plug-in, and firmware (programmed into a chip) in a recorder-mixer.
Guitar Amplifier Modeler
Another simulator takes the sound of a direct-recorded guitar, and makes
the guitar sound like it is played through a guitar amp (CD track 38).
Several amp models can be simulated, as well as effects, tone, drive, the
mic used to pick up the amp, and the mic’s position.
Two hardware examples of amp modelers are the Line 6 Pod and
the Johnson J Station. Amp Farm is a guitar modeling plug-in for Pro
Tools. Roland’s digital workstations offer COSM mic modeling and
guitar-amp modeling.
Guitar processors or guitar stomp boxes can be used on any instrument or vocal to add distortion, or to generally “shred” the sound for a
low-fi effect.
De-Click, and De-Noise
Also called “Audio restoration progams”, these are plug-ins—or standalone programs—that can remove the clicks and pops from LP records,
or remove hiss and hum from noisy recordings.
Surround Sound
Recent plug-ins for surround sound are surround panning, surround
reverb, and surround encoding/decoding.
Multieffects Processor
This provides several effects in a single device or plug-in. Some units let
you combine up to four effects in any order. Others have several chan-
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10
nels, so you can put a different effect on different instruments. With most
processors, you can edit the sounds and save them in memory as new
programs. On the enclosed CD, tracks 29–38 demonstrate various effects on
voice.
An extension of the multieffects processor is the vocal processor. It
includes a high-quality mic preamp or two, plus EQ, compression, gating,
de-esser, and perhaps some tube saturation distortion.
A multieffects processor uses a digital signal processing (DSP) chip
and RAM memory. The amount of memory is limited, so the more
memory that one effect uses, the less is available for other effects. For
example, suppose you’re combining reverb and echo. If you use a reverb
with a long decay time (which takes a lot of memory), you may have to
settle for an echo with a short delay.
Most units have a frequency response up to 20 kHz and at least 16bit resolution. They offer 100 or more programmable presets with MIDI
control over any parameter. For example, with some units you can place
an instrument in a simulated room, and use a MIDI controller to continuously change the size of that room.
Many signal processors can be controlled by MIDI program-change
commands. You can quickly change the type of effect, or effect parameters, by entering certain program changes into a sequencer.
Suppose you want each tom-tom hit in a drum fill to have a different size room added to it. For example, put the high-rack tom in a small
room; put the low-rack tom in a concert hall; and put the floor tom in a
cave. To do this, first assign a different program number (patch or preset
number) to each effects parameter. You do this with the effects device.
Then, using the sequencer, punch in the appropriate program number for
each note.
A MIDI program-change footswitch lets guitarists call up different
effects on MIDI signal processors. By tapping a footswitch, they can get
fuzz, flanging, wah-wah, spring reverb, and so on.
A MIDI mapper lets you control some effects parameters with any
controller. For example, vary reverb decay time with a pitch wheel, or
vary a filter with key velocity.
Looking Back
We’ve come a long way with effects. Looking back over the past few
decades, each era had its own “sound” related to the effects used at the
time. The ’50s had tube distortion and slap echo; the ’60s used fuzz,
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wah-wah, and flanging. Much of the early ’70s sounded dry, and the early
’90s emphasized synth, drum machines, and gated reverb. Now vacuum
tubes and acoustic instruments are back, along with occasional low-fi
(tinny, distorted, or noisy) sounds and dry vocals. Whatever effects you
choose, they can enhance your music if used with taste.
Sound-Quality Glossary
The sound of effects and EQ can be hard to translate into engineering
terms. For example, what EQ should you use to get a “fat” sound or a
“thin” sound? The glossary below may help. It’s based on conversations
with producers, musicians, and reviewers over many years. Not everyone agrees on these definitions, but they are common.
AIRY Spacious. The instruments sound like they are surrounded by a
large reflective space full of air. A pleasant amount of reverb. Highfrequency response that extends to 15 or 20 kHz.
BALLSY OR BASSY Emphasized low frequencies below about 200 Hz.
BLOATED Excessive mid-bass around 250 Hz. Poorly damped low
frequencies, low-frequency resonances.
BLOOM Adequate low frequencies. Spacious. Good reproduction of
dynamics and reverberation. Early reflections or a sense of “air” around
each instrument in an orchestra.
BOOMY Excessive bass around 125 Hz. Poorly damped low frequencies or low-frequency resonances.
BOXY Having resonances as if the music were enclosed in a box.
Speaker cabinet diffraction or vibration. Sometimes an emphasis around
250 to 500 Hz.
BREATHY Audible breath sounds in vocals, flute, or sax. Good highfrequency response.
BRIGHT High-frequency emphasis. Harmonics are strong relative to
fundamentals.
BRITTLE High-frequency peaks, or weak fundamentals. Slightly distorted or harsh highs. Opposite of round or mellow. See Thin. Objects
that are physically thin and brittle emphasize highs over lows when you
crack them.
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Effects and Signal Processors
CHESTY A vocal signal with a bump in the low-frequency response
around 125 to 250 Hz.
CLEAN
Free of noise, distortion, and leakage.
CLEAR
See Transparent.
CLINICAL Too clean or analytical. Emphasized high-frequency
response, sharp transient response. Not warm.
COLORED Having timbres that are not true to life. Non-flat response,
peaks, or dips.
CONSTRICTED Poor reproduction of dynamics. Dynamic compression. Distortion at high levels. Also see Pinched.
CRISP Extended high-frequency response. Like a crispy potato chip, or
crisp bacon frying. Often referring to cymbals.
CRUNCH
DARK
Pleasant guitar-amp distortion.
Opposite of bright. Weak high frequencies.
DELICATE High frequencies extending to 15 or 20 kHz without peaks.
A sweet, airy, open sound with strings or acoustic guitar.
DEPTH A sense of closeness and farness of instruments, caused by
miking them at different distances. Good transient response that reveals
the direct/reflected sound ratio in the recording.
DETAILED Easy-to-hear tiny details in the music; articulate. Adequate
high-frequency response, sharp transient response.
DRY Without effects. Not spacious. Reverb tends towards mono instead
of spreading out. Overdamped transient response.
DULL See Dark.
EDGY Too-strong high frequencies. Trebly. Harmonics are too strong
relative to the fundamentals. When you view the waveform on an oscilloscope, it even looks edgy or jagged, because of excessive high frequencies. Distorted, having unwanted harmonics that add an edge or
raspiness to the sound.
EFFORTLESS Low distortion, usually coupled with flat response.
ETCHED
higher.
Clear but verging on edgy. Emphasis around 10 kHz or
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FAT See Full and Warm. Also, a diffuse spatial effect. Also, smeared out
in time, with some reverberant decay.
FOCUSED Referring to the image of a musical instrument which is
easy to localize, pinpointed, having a small spatial spread.
FORWARD
2 to 5 kHz.
Sounding close to the listener, projected. Emphasis around
FULL Opposite of Thin. Strong fundamentals relative to harmonics.
Good low-frequency response, not necessarily extended, but with adequate level around 100 to 300 Hz.
GENTLE Opposite of edgy. The harmonics—highs and upper mids—
are not exaggerated, or may even be weak.
GLARE, GLASSY A little less extreme than edgy. A little too bright or
trebly.
GRAINY The music sounds like it’s segmented into little grains, rather
than flowing in one continuous piece. Not liquid or fluid. Suffering
from harmonic or IM distortion. Some early A/D converters sounded
grainy, as do current ones of inferior design. “Powdery” is finer than
“grainy”!
GRUNGY
Lots of harmonic or IM distortion.
HARD Too much upper midrange, usually around 3 kHz. Or, good
transient response, as if the sound is hitting you hard.
HARSH Too much upper midrange. Peaks in the frequency response
from 2 to 6 kHz. Or, excessive phase shift.
HEAVY Good low-frequency response below about 50 Hz. Suggesting
great weight or power, like a diesel locomotive or thunder.
HOLLOW
dip.
See Honky. Or, too much reverberation. Or, a mid-frequency
HONKY The music sounds the way your voice sounds when you cup
your hands around your mouth. A bump in the response around 500 to
700 Hz.
LIQUID Opposite of grainy. A sense of seamless flowing of the music.
Flat response and low distortion. High frequencies are flat or reduced
relative to mids and lows.
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LOW-FI (low fidelity) “Trashy” sounding. Tinny, distorted, noisy, or
muddy.
MELLOW Reduced high frequencies, not edgy.
MUDDY Not clear. Weak harmonics, smeared time response, IM distortion. Too much reverb at low frequencies. Too much emphasis around
200 to 350 Hz.
MUFFLED The music sounds covered up. Weak highs or weak upper
mids.
MUSICAL Conveying emotion. Flat response, low distortion, no
edginess.
NASAL The vocalist sounds as if he or she is singing with the nose
closed. Also applies to strings. Bump in the response around 300 to
1000 Hz. See Honky.
NEUTRAL Accurate tonal reproduction. No obvious colorations. No
serious peaks or dips in the frequency response.
PAPERY Referring to a kick drum that has too much output around 400
to 600 Hz.
PINCHED Narrowband. Midrange or upper-midrange peak in the
frequency response. Pinched dynamics are overly compressed.
PIERCING Strident, hard on the ears, screechy. Having sharp, narrow
peaks in the response around 3 to 10 kHz.
PRESENT, PRESENCE Adequate or emphasized response around
5 kHz for most instruments, or around 2 to 5 kHz for kick drum and
bass. Having some edge, punch, detail, closeness, and clarity.
PUFFY Bump in the response around 500 to 700 Hz.
PUNCHY Good reproduction of dynamics. Good transient response.
Sometimes a bump around 5 kHz or 200 Hz.
RASPY Harsh, like a rasp. Peaks in the response around 6 kHz which
make vocals sound too sibilant or piercing.
RICH See Full. Also, having euphonic distortion made of even-order
harmonics.
ROUND High-frequency rolloff or dip. Not edgy.
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SHARP
See Strident and Tight.
SIBILANT, ESSY Exaggerated “s” and “sh” sounds in singing, caused
by a rise in the response around 5 to 10 kHz.
SIZZLY
See Sibilant. Also, too much highs on cymbals.
SMEARED Lacking detail. Poor transient response. This may be a
desirable effect in large-diameter mics. Also, poorly focused images.
SMOOTH Easy on the ears, not harsh. Flat frequency response, especially in the midrange. Lack of peaks and dips in the response. Low
distortion.
SPACIOUS Conveying a sense of space, ambience, or room around the
instruments. To get this effect, mike farther back, mix in an ambience mic,
add reverb, or record in stereo. Components that have out-of-phase
crosstalk between channels may add false spaciousness.
SQUASHED Overly compressed.
STEELY Emphasized upper mids around 3 to 6 kHz. Peaky, nonflat
high-frequency response. See Glassy, Harsh, Edgy.
STRAINED The component sounds like it’s working too hard. Distorted. Inadequate headroom or insufficient power. Opposite of effortless.
STRIDENT See Harsh and Edgy.
SWEET Not strident or piercing. Flat high-frequency response, low distortion. Lack of peaks in the response. Highs are extended to 15 or
20 kHz, but they are not bumped up. Often used when referring to
cymbals, percussion, strings, and sibilant sounds.
THIN Fundamentals are weak relative to harmonics. Note that the fundamental frequencies of many instruments are not very low. For example,
violin fundamentals are around 200 to 1000 Hz. So if the 300-Hz area is
weak, the violin may sound thin—even if the mic’s response goes down
to 40 Hz.
TIGHT Good low-frequency transient response. Absence of ringing or
resonance when reproducing the kick drum or bass. Good low-frequency
detail. Absence of leakage.
TINNY, TELEPHONE-LIKE Narrowband, weak lows, peaky mids.
The music sounds like it’s coming through a telephone or tin can.
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TRANSPARENT Easy to hear into the music, detailed, clear, not
muddy. Wide, flat frequency response, sharp time response, very low
distortion and noise.
TUBBY See Bloated. Having low-frequency resonances as if you’re
singing in a bathtub.
VEILED The music sounds like you put a silk veil over the speakers.
Slight noise or distortion, or slightly weak high frequencies.
WARM Good bass, adequate low frequencies, adequate fundamentals
relative to harmonics. Not thin. Or, excessive bass or mid-bass. Or, pleasantly spacious, with adequate reverberation at low frequencies. Or, gentle
highs, like from a tube amplifier. See Rich.
WOOLY, BLANKETED The music sounds like there’s a wool blanket
over the speakers. Weak high frequencies or boomy low frequencies.
Sometimes, an emphasis around 250 to 600 Hz.
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11
MIXERS AND MIXING
CONSOLES
The heart of your recording studio is the mixer. It’s a control center where
you plug in all sorts of signals; mix or blend them; add effects, EQ, and
stereo positioning; and route the signals to recorders and monitor speakers. A mixing console (also called board or desk) is a large mixer with
many controls. This chapter covers three types of mixers: analog hardware, digital hardware, and digital software mixers.
A recorder-mixer combines a mixer and a multitrack recorder in a
single portable chassis. This convenient unit is also called a ministudio
or portable studio. Low-end recorder-mixers record 4 tracks, and highend units record 8 to 32 tracks.
This chapter covers both mixers and mixing consoles. First we’ll look
at typical features of both, then at features found only in large mixing
consoles.
Stages of Recording
This chapter will refer to the three stages in making a multitrack recording: recording, overdubbing, and mixdown.
1. Recording (tracking): The mixer accepts mic-level signals and amplifies them up to line level. You send the line-level signal from each
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Practical Recording Techniques
mic to a separate track in a multitrack recorder. The multitrack
recorder records several tracks on tape, MiniDisc, or hard disk. One
track might be a lead vocal, another track might be a saxophone, and
so on.
2. Overdubbing While listening to prerecorded tracks over
headphones, the musician records new parts on open (unused)
tracks.
3. Mixdown: After all the tracks are recorded, mix or combine them
into 2-track stereo or 6-channel surround. Add effects. Record the
stereo mix with a 2-track recorder, such as a DAT recorder, CD-R
burner, or hard drive. This recording can be duplicated on a CD-R
(recordable compact disc).
Mixer Functions and Formats
Although the knobs and meters on a mixer may appear intimidating, you
can understand them if you read the manual and practice with the equipment. A mixer is complicated because it lets you control many aspects of
sound:
• The loudness of each instrument (to control the balance among
instruments in the mix)
• The tone quality of each instrument (bass, treble, midrange)
• The room that the instruments are in (reverberation)
• The left-to-right position of each instrument (panning)
• Effects (flanging, echo, chorus, etc.)
• Track assignments (put one or more instruments on each recorder
track)
• Recording level (to prevent distortion and noise in the recorder)
• Monitor selection (what you want to listen to)
Mixers come in many formats:
• An analog mixer is a control device that works on analog signals,
and sends them to an external multitrack recorder and 2-track
recorder.
• A digital mixer is the same, but works internally with digital signals.
It accepts analog or digital signals.
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Mixers and Mixing Consoles
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• A software mixer exists only in your computer as part of digital
recording software. You control it with a mouse or a controller
surface (described next). The recording is done on your hard drive.
• A controller surface is a device that looks like a mixer with faders
and knobs. It plugs into your computer’s USB or FireWire port and
controls the software mixer.
A mixer can be specified by the number of inputs and outputs it has. For
example, an 8-in, 2-out mixer (8 ¥ 2 mixer) has 8 signal inputs that can
be mixed into 2 output channels (buses) for stereo recording. Similarly, a
16-in, 8-out (16 ¥ 8) mixing board has 16 signal inputs and 8 output channels for multitrack recording. A 16 ¥ 4 ¥ 2 mixing board has 16 inputs, 4
submixes or groups (explained under the heading “Output Section”) and
2 master outputs. There also are connectors for external equipment, such
as effects devices and a monitor power amplifier. The more inputs your
mixer has, the more instruments you can record at the same time. If
you’re recording only yourself, you may need only two inputs.
Let’s look at the analog mixer in more detail. Knowing how it works
will help you understand the other types.
Analog Mixer
A mixer can be divided into three sections: input, output and monitor.
Here are the main parts of each section and what they do:
Input section
• Inputs connect to your mics, electric instruments, and recorder
outputs.
• Faders are sliding volume controls that affect the loudness of each
instrument. This lets you control the balance among instruments in
the mix.
• Equalization (EQ) knobs adjust the tone quality of each instrument
(bass, treble, midrange).
• Aux knobs set the amount of reverb or other effects, and also can be
used to set up a monitor mix or headphone mix.
• Pan pots place the monitored sound of each track where desired
between your stereo speakers—left, center, right, or anywhere
between. In some mixers, the pan pot is also used with the assign
switch during recording to send signals to the desired tracks.
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Practical Recording Techniques
• Channel assign buttons route each input signal to the desired
recorder track.
Output section
• Master faders set the overall level.
• Outputs connect to your recorder inputs and the monitor power
amplifier.
• Meters help you set the correct recording level (to prevent distortion
and noise).
Monitor section
• Monitor controls select what you want to listen to.
• Aux knobs or channel faders set up the monitor mix.
Let’s look at each part in more detail.
Input Section
A mixer is made of groups of controls called modules. An input module
(Figure 11.1) affects a single input signal—from a microphone, for
instance. The module is a narrow vertical strip, one per input. Several
modules are lined up side-by-side. Each input module is the same, so if
you know one, you know them all.
GAIN TRIM
aux 1
aux 2
AUX
HF
MF
EQ
LF
PAN
CLIP LED
FADER
ASSIGN
Figure 11.1
240
A typical input module.
Mixers and Mixing Consoles
11
Let’s follow the signal flow from input to output through a typical
input module (Figure 11.2). Every mixer is a little different, but you are
likely to find features like those described here.
Input Connectors
On the back of each input module are input connectors with these labels:
MIC: Accepts signals from a microphone or direct box
LINE: Accepts an electric musical instrument, or a track output of a
multitrack recorder
TRACK: Accepts a track output of a multitrack recorder; not
included in all mixers
Some units use a single jack for both mic and line inputs; others have separate jacks for each. The mic input is either an unbalanced 1/4-inch phone
jack (a 1/4-inch hole) or an XLR-type connector (with three small holes).
The line input is either a 1/4-inch phone jack, an RCA phono jack (like
you see on a stereo system), or an XLR-type connector.
You can plug a synthesizer directly into a phone-jack line input
without using a direct box if the cable is under 10 feet; a longer cable may
pick up hum. In that case, use a direct box plugged into a mic input.
In some mixers, a phone-jack input is switchable between low
impedance (for microphones) or high impedance (for electric guitar
pickups). Other mixers might have a separate low-impedance input and
a high-impedance input.
GAIN
OR
TRIM
OVERLOAD
(CLIP) LED
INPUT
SELECTOR
SWITCH
MIC
PREAMP
INPUT
CONNECTORS
MUTE
EQ
CHANNEL
ASSIGN
SWITCH
PAN
POT
INSERT SEND
INSERT RETURN
PRE-FADER
AUX SEND
1
To the
3 group
2
FADER
LINE
Figure 11.2
DIRECT
OUT
JACK
mixing
circuits
4
POST-FADER
AUX SEND
Signal flow through a typical input module.
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Practical Recording Techniques
Phantom Power (P48, +48)
This switch (not shown) turns on phantom power (48V DC) for condenser
microphones. In the mic input connector, the 48V appears on pins 2 and
3 relative to pin 1. The microphone receives phantom power and sends
audio along the same two cable leads.
Mic Preamp
After entering the mic connector, the microphone signal goes to a mic preamplifier inside the mixer. This preamp boosts or amplifies the weak
microphone signal up to a higher voltage, making it a line-level signal.
Trim (Gain)
The TRIM or GAIN control adjusts the amount of amplification in the mic
preamp. If the gain control is turned up full, and the incoming mic signal
is very strong due to a loud instrument or vocal, this signal can overload
the mic preamp. This causes distortion—a gritty sound. To get a good
signal-to-noise ratio (S/N) in your mixer, set the gain control as high as
possible, but not so high that the preamp distorts.
Here’s how: Start with the trim turned up all the way down (counterclockwise). In most mixers, each input module has a tiny light (LED)
labeled “clip,” “peak,” or “OL” (overload). It flashes when the mic
preamp is distorting. When an instrument is playing its loudest signal
through an input module, gradually turn up the trim control until the
clip LED starts flashing. Then turn down the trim control just to the point
where the light stays off, and turn it down another 10 dB for extra
headroom.
Some low-cost mixers do not have a trim control. The input fader
serves this function.
Input Selector Switch
This switch lets you select the type of signal you want to work with. Some
common switch labels are below:
MIC (Mic or direct box)
LINE (For line-level signals: a synthesizer, drum machine, electric
guitar, or multitrack recorder’s track output)
INPUT (Mic or line)
TRACK (Multitrack recorder’s track output)
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Mixers and Mixing Consoles
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MUTE No signal is processed; during mixdown, it’s a good idea to
mute tracks that have nothing playing at the moment to reduce tape
hiss
Using the input selector is simple. If you plugged in a microphone or
direct box to record its signal, set the input selector to MIC or INPUT. If
you plugged in a synth, drum machine, or electric guitar, set the selector
to LINE or INPUT. When you’re ready to mix, select TRACK (if available) or LINE (if the recorder track outputs are plugged into mixer line
inputs).
Some mixers have no input selector. The mixer processes whatever
signal is plugged in.
In some recorder-mixers, a single 1/4-inch phone jack is used
both for mic-level and line-level signals. A mic-level signal is typically
about 1 to 2 millivolts. A line-level signal is about 0.3 to 1.23 volts.
The two levels are handled either by a MIC/LINE switch or a TRIM
control.
Insert Jacks
Following the input selector switch are the insert-send jack and insertreturn jack (on the back of each input module). Or the mixer might
have a single insert jack, a TRS type that has the send on the tip terminal
and the return on the ring terminal. Inside the mixer, the send is
connected to the return so that the signal passes through to the rest of
the mixer.
If you insert a plug into the insert jack(s), you break the signal
path so you can insert an external device there in series with the input
module’s signal. You might insert a compressor into the signal path
of one module for automatic volume control, or insert any other
signal processor (reverb/delay, for instance). That way, if all your aux
sends are tied up, you can add another signal processor. On the
reverb/delay unit, set the dry/wet mix control for the desired amount of
effect.
Another use for the insert jack is to send the mic-preamp output
signal to a multitrack recorder track. The output of each track returns to
the insert jack and continues though your mixer. In this case, you use the
trim controls to set recording levels, and use the faders, EQ, and aux
sends to set up a monitor mix.
Low-cost mixers omit the insert jacks. Some units have insert jacks
on only two inputs.
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Practical Recording Techniques
Input Fader (Channel Fader)
Next, the input signal that you selected goes to a fader. This is a sliding
volume control for each input signal. During recording, you can use the
fader in two ways. If you are recording one instrument per track, record
off the insert send and use the fader to adjust the instrument’s level in
the monitor mix. If you are recording two or more instruments on one
track, record off a group output, and use each instrument’s fader to set
up a mix within that group. For example, if you are recording several
drum mics onto one track, set up a drum mix with the drum-mic faders.
During mixdown, you use the faders to set the loudness balance
among instruments.
EQ
The signal from the input fader goes to an equalizer, which is a tone
control. With EQ you can make an instrument sound more or less bassy,
and more or less trebly, by boosting or cutting certain frequencies. See
Chapter 10 for details.
Direct Out
The direct out is an output connector following each input fader and
equalizer. The signal at the direct-out jack is an amplified, equalized
version of the input signal. The fader controls the level at the directoutput jack. You can use the direct-out jack when you want to record one
instrument per track (with EQ) on an external multitrack recorder.
Connect the direct-out jack to a multitrack recorder track input. Because
the direct output bypasses the mixing circuits farther down the chain, the
result is a cleaner signal.
Suppose your mixer has 8 inputs and 2 outputs. You can use this
mixer with an 8-track recorder. Just connect the direct-out jack in each
input module to a separate track input. Or do the same with the insertsend jacks.
Channel Assign Switch
The equalized signal also goes through a pan pot (explained in the section
below) to the channel assign switch or track selector switch. It lets you
send the signal of each instrument to the recorder track you want to
record that instrument on.
A mixer with four groups or buses would have an assign switch
labeled 1, 2, 3, 4. If you want to record bass on track 1, for instance, find
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Mixers and Mixing Consoles
11
the assign switch for the input module the bass is plugged into, and push
assign switch 1. If you want to record four drum mics on track 2, push
assign switch 2 for all those input modules.
Some mixers assign tracks with two controls: a selector switch and
a pan pot.
Pan Pot
This knob sends a signal to two channels in adjustable amounts. By rotating the pan-pot knob, you control how much signal goes to each channel.
Set the knob all the way left and the signal goes to one channel. Set it all
the way right and the signal goes to the other channel. Set it in the middle
and the signal goes to both channels equally.
Here’s how you might use a pan pot to assign an instrument to a
track. The channel-assign switch might have two positions labeled 1–2
and 3–4. If you turn the pan pot left, the signal goes to odd-numbered
tracks (either 1 or 3, depending on how you set the assign switch). If you
turn the pan pot right, the signal goes to even-numbered tracks (2 or 4).
Suppose you want to assign the bass to track 1. Set the assign switch
to 1–2, and turn the pan pot far left to choose the odd-numbered track
(track 1).
During mixdown, the pan pot has a different function: It places
images between your speakers. An image is an apparent source of sound,
a point between your speakers where you hear each instrument or vocal.
Set the pan pot to locate each instrument at the left speaker, right speaker,
or anywhere in between. If you set the pan pot to center, the signal goes
equally to both channels, and you hear an image in the center.
Aux
The aux or aux-send function (Figures 11.2 and 11.3) sends some of
the input module’s signal to equipment outside the mixer. A pre-fader
aux send is before the fader, and usually goes to a power amp that
feeds monitor speakers or headphones. You can use the pre-fader
aux knobs to set up a monitor mix—a balanced blend of input signals
you hear over speakers or headphones. A post-fader aux send is after the
fader and EQ, and usually goes to an effects unit. You use the post-fader
aux knobs to set the amount of effects (reverb, echo) heard on each instrument in a mix.
Some mixers have no aux sends, some have one aux-send control
per module, and some have two or more (labeled aux 1, aux 2, etc.). The
more aux sends you have, the more you can play with effects, but the
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Practical Recording Techniques
INPUT
FADER
GROUP
MIXING CIRCUIT
(TYPICAL OF 4)
EQ,
PAN,
ASSIGN
INPUT
SIGNAL
AUX 1
(EFFECTS)
AUX 1
SEND
Signals from
other aux 1
knobs
Signals from
other input
modules
EXTERNAL
EFFECTS UNIT
GROUP
OUT
AUX RETURN
OR BUS IN
AUX 2
(MONITOR)
Signals from
other aux 2
knobs
Figure 11.3
AUX 2
SEND
To monitor amp
Aux sends.
greater the cost and complexity. The aux number (1 or 2) is not necessarily assigned a specific function; you decide what you want aux 1 and
aux 2 to do.
During recording and overdubbing, the aux knobs of all the input
modules can be used to create a monitor mix. The monitor mix that you
create with the aux knobs is independent of the levels going to the multitrack recorder. You use the gain-trims during recording to set recording
levels, and you use the aux knobs to create an independent mix that is
heard over your monitor system.
In Figure 11.3, the aux-2 send control is just before the fader. In this
mixer, the signals from all the aux-2 knobs in the mixer combine at a connector jack labeled “aux-2 send.” You can connect that jack to your power
amplifier, which drives monitor speakers and headphones.
In Figure 11.3, the aux-1 send control is just after the fader. During
mixdown, each aux-1 knob controls how much effects (reverb, echo) you
hear on each track. In each input module, the aux knob adjusts how much
of that input signal is sent to an external effects unit. The effected signal
returns to the mixer’s aux-return or bus-in jacks, where it blends with the
original signal.
For example, suppose the aux-1 send is connected to a digital
reverb. The more you turn up the aux-1 send knob, the more signal
goes to the reverb. The output of the reverb unit returns to the mixer’s
bus-in jack, and blends with the original dry signal, adding a spacious
effect.
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Mixers and Mixing Consoles
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A few mixers have an aux-return control (also called effects-return
or bus-in) that sets the overall effects level returning to the mixer.
Follow these steps to use the aux controls to adjust the amount of
effects heard on each track:
1. Patch an effects unit between your mixer’s aux-send and aux-return
(bus-in) jacks.
2. On the effects unit, set the dry/wet mix control all the way to “wet”
or “effect.”
3. If your mixer has aux-return (bus-in) knobs, turn them about half
way up and pan their signals hard left and right.
4. Turn up the aux-send knob for each input, according to how much
effect you want to hear on that input signal. Suppose you’re using
reverb as an effect. You might turn it up by different amounts for the
vocals, drums, and lead guitar, and leave it turned down for the bass
and kick drum.
As you’re setting the aux levels, check the overload indicator on the
effects unit. If it’s flashing, turn down the input level on the effects unit
just to the point where the overload light stops flashing. Then turn up
the output level on the effects unit (or turn up the aux return on the mixer)
to achieve the same amount of effect you heard before.
There might be a pre/post switch next to the aux-send knob. When
an aux knob is set to pre (pre-fader), its level is not affected by the fader
setting. You use the pre setting for a headphone mix during recording or
overdubbing because you don’t want the fader settings to affect the
monitor mix.
The post setting (post-fader) is used for effects during mixdown. In
this case, the aux level follows the setting of the fader. The higher you set
the track volume with the fader, the higher the effects level. But the
dry/wet mix stays the same.
Output Section
The output section is the final part of the signal path; the section that
feeds mixed signals to the recorder tracks. It includes mixing circuits,
submaster or group faders (sometimes), master faders, and meters
(Figure 11.4).
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Practical Recording Techniques
INPUT MODULE (ONE OF SEVERAL)
INPUT
FADER
EQ,
PAN,
ASSIGN
Input
signal
from mic
or line
To the
group
mixing
circuits
OUTPUT MODULE
GROUP
MIXING
CIRCUITS
3
4
Figure 11.4
Group 1 out
1
Signals from
2
the assign
switches of all
the input modules
METER
(TYPICAL OF 4)
Group 2 out
GROUP
FADERS
Group 3 out
Signals
from 1
group 2
outs 3
MASTER
FADERS
CH.1
4
STEREO
MIX BUS
1
2
3
4
To recorder
Ch. 1 in
CH.2
To recorder
Ch. 2 in
Group 4 out
Input module and output section of a mixer.
Mixing Circuits (Active Combining Networks), Group Faders,
and Bus Output Connectors
The group mixing circuits are in the center of Figure 11.4. Recall that you
use the assign switches to send each input signal to the desired channel
or bus, and each bus feeds a different recorder track. A bus is a channel
in a mixer containing an independent mix of signals. The bus 1 or group
1 mixing circuit accepts the signals from all the inputs you assigned to
bus 1 and mixes them together to feed track 1 of the recorder. The bus 2
mixing circuit mixes all the bus 2 assignments, and so on.
Following each group mixing circuit is a group fader. If you assigned
all the drum mics to group 1, the group 1 fader adjusts the overall level
of the drum mix. The signal from each group fader goes to a group or
bus output connector in your mixer. You can connect each bus output to
a recorder track input.
Stereo Mix Bus, Master Faders, Main Output Connectors
The stereo mix bus are two group mixing circuits: one for channel 1 and
one for channel 2. Three types of signals feed into the stereo mix bus:
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Mixers and Mixing Consoles
11
1. The group output signals.
2. Signals from input modules. You can assign an input module’s
signal directly to the stereo mix bus, bypassing the groups. This
results in lower noise.
3. Effects-return signals, such as the reverberated signal from an external digital reverb.
Located on the right side of your mixer, the stereo master faders are one
or two sliding volume controls that affect the overall level of the stereo
mix bus. Usually, you set the master fader(s) within design center, the
shaded area about three-quarters of the way up on the scale. This setting
minimizes mixer noise and distortion. You can fade out the end of a mix
by turning down the master faders gradually.
After the master faders, the signal goes to a pair of main output
connectors, which feed a 2-track recorder of your choice.
You feed the multitrack recorder either from group outputs, direct
outs, or insert sends. If you’re mixing several instruments to track 5, for
example, assign those instruments’ signals to Group 5. Connect the
Group 5 output to recorder track 5 in. If you’re recording one instrument
on track 5, however, connect that instrument’s direct out or insert send
to track 5 in. The signal is cleaner at the direct out or insert send than at
the group output.
Some mixing consoles have voltage controlled amplifier (VCA)
group faders. A VCA group fader acts like a remote control for groups of
channel faders. For example, you could assign each drum mic’s fader to
a group, which is an audio path, and also assign each drum mic’s fader
to a VCA group, which is a fader that controls all the drum mic channels
at once.
Meters
Meters are an important part of the output section. They measure the
voltage level of various signals. Usually, each group or bus output has a
meter to measure its signal level. If these buses feed the recorder tracks,
you use the meters to set the recording level for each track.
A mixer has either VU meters or LED bar graph meters.
• A VU meter (now rarely used) is a voltmeter that shows approximately the relative loudness of various audio signals. Set the record
level so that the meter needle reaches +3 VU maximum for most
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Practical Recording Techniques
signals, and about -6 VU maximum for drums, percussion, and
piano. That’s necessary because the VU meter responds too slowly
to show the true level of percussive sounds.
• An LED bar graph meter has a column of lights (LEDs) that shows
peak recording level. Usually you set the recording level to peak
near 0 dB maximum.
Monitor Section
The monitor section is used to control what you’re listening to. It lets you
select what you want to hear, and lets you create a mix over headphones
or speakers to approximate the final product. The monitor mix has no
effect on the levels going to your recorder.
During recording, you want to monitor a mix of the input signals.
During playback or mixdown, you want to hear a mix of the recorded
tracks. During overdubs, you want to hear a mix of the recorded tracks
and the instrument that you’re overdubbing. The monitor section lets you
do this.
Monitor Select Buttons
These buttons let you choose what signal you want to monitor or listen
to. Because the configuration of these buttons varies widely among different mixers, they are not shown in Figure 11.4.
If you want to use aux 2 as the monitor bus, select the aux-2 bus as
the monitor source. Some mixers have no monitor-select switches.
Instead, you always monitor the stereo mix bus.
Monitor Mix Controls and Connectors
One way to set up a monitor mix is with the aux knobs. Suppose you
want aux 2 to be the monitor mix. Connect the aux-2 send jack to your
power amp and speakers. Or if you’re using headphones, switch them to
monitor the aux-2 bus. Turn up all the aux-2 knobs about halfway, then
turn each knob up or down to set a good loudness balance. You do this
during recording or overdubbing.
Here’s another way to set up a monitor mix using the faders.
Connect your multitrack recorder ins and outs to the insert jacks (Figure
11.5). Connect the insert-jack 1 tip (send) to track 1 in; connect track 1 out
to the insert-jack ring (return). Make similar connections for the other
tracks. Also connect the mixer’s monitor-out jacks to your power amp
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Mixers and Mixing Consoles
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Figure 11.5 Using insert jacks to send each input signal to a recorder track.
The track signal returns to the mixer, where you adjust level, panning, EQ, and
effects.
and speakers. Monitor the stereo mix bus. With this setup, use the
trim controls to set recording levels. Use the faders to set up a monitor
mix, cue mix, or mixdown with EQ and effects. It’s a convenient way to
work.
In a split console (side-by-side console), a separate monitor mixer is
built into the control surface. This monitor mixer has level, pan, and aux
controls for each track. In an in-line console (I/O console), the monitor
mix is done with the aux knobs or fader in each input module. This is the
most common type of console.
During mixdown, monitor the stereo mix bus.
SOLO
The SOLO button in an input module lets you monitor one instrument
or vocal at a time so you can hear it better. By pressing two or more SOLO
buttons, you can monitor more than one input signal at a time.
Suppose you hear a buzz in the audio and suspect it may be in the
bass guitar signal. If you push the SOLO button in the bass guitar’s input
module, you’ll monitor only the bass guitar. Then you can easily hear
whether the buzz is in that input.
On British consoles, the SOLO function is called pre-fader listen
(PFL) or after-fader listen (AFL).
Additional Features in Large Mixing Consoles
Large mixing consoles have more features than small mixers do. If you’re
working only with a small mixer or a recorder-mixer, you might want to
skip this section.
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Practical Recording Techniques
FOLD BACK (FB): Another name for cue, or headphone mix.
PHASE (POLARITY INVERT): Used only with balanced lines, this
switch inverts the polarity of the input signal. That is, it switches
pins 2 and 3 to flip the phase 180 degrees at all frequencies. You
might use it to correct a miswired mic cable whose polarity is
reversed. If you mic a snare drum top and bottom, you need to invert
the polarity of the bottom mic.
AUTOMATED MIXING CONTROLS: These controls (Read, Write,
Update, Record Automation, Play automation) set up the console for
various automation functions. With automation, a memory circuit in
the mixer remembers your console settings and mix moves. You can
recall the settings with the push of a button, then continue working
on the mix. More on automated mixing is at the end of Chapter 12.
EFFECTS PANNING: This feature places the images of the effects
signals wherever desired between the monitor speakers. Some consoles let you pan effects in the monitor mix as well as in the final
program mix.
EFFECTS RETURN TO CUE: This is an effects-return level control
that adjusts the amount of effects heard in the studio headphone
mix. These monitored effects are independent of any effects being
recorded.
EFFECTS RETURN TO MONITOR: This effects-return control
adjusts the amount of effects heard in the monitor mix. These monitored effects are independent of any effects being recorded.
BUS/MONITOR/CUE switch for effects return: A switch that feeds
the effects-return signal to your choice of three destinations:
program bus (for mixdown), monitor mix, cue mix, or any combination of the three.
METER SWITCHES: In many consoles, the meters can measure
signal levels other than console output levels. Switches near the
meters can be set so that the meters indicate bus level, aux-send
level, aux-return level, monitor-mix level, etc.
Those readings help you set optimum levels for the outboard devices
receiving those signals. Too low a level results in noise; too high a level
causes distortion in the outboard unit. For example, if the aux-return
signal sounds garbled or distorted, the cause may be an excessive auxsend level. Verify that condition by checking the meters switched to read
the aux or effects bus.
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Mixers and Mixing Consoles
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DIM: A switch that reduces the monitor level by a preset amount so
you can talk (as in “dim the lights”).
TALKBACK: An intercom between the control room and studio. A
mic built into the console lets you talk to the musicians in the studio
when you push the talkback button.
SLATE: This function routes the control-room microphone signal to
all the buses so you can record the name of the tune and take
number.
OSCILLATOR or TONE GENERATOR: This is used to put a levelcalibration tone on a DAT tape, or to reference the recorder’s meters
to those on the console. You also can use it to check signal path,
levels, and channel balance.
Digital Mixer
So far we’ve looked at the analog mixing console, which works entirely
with analog signals. A digital mixing console accepts analog or
digital signals. It converts the analog signals to digital, and processes
all signals internally in digital format. The signal stays in the digital
domain for all mixer processing. Level changes, EQ, and so on are done
by digital signal processing (computer calculations) rather than by analog
circuits.
In a digital console, each analog input signal goes through an
analog-to-digital (A/D) converter so that the mixer can process the signal
digitally. Some of the digital output signals from the mixer go through
digital-to-analog (D/A) converters. The resulting analog signals feed a
power amp, effects unit, and so on.
Analog and digital consoles operate differently. To use EQ in
an analog console, you find the channel you want to EQ, and adjust
its EQ knobs. To use EQ in a digital console, you press a button to select
the channel you want to equalize, and press an EQ button. Then the EQ
settings for that channel show up on an LCD screen. You press buttons
and turn a knob to adjust the EQ frequency and boost/cut for that
channel.
Because one knob controls the EQ for all the channels, digital consoles have fewer controls than analog consoles. One knob or switch can
have several functions. This makes digital consoles harder to operate
because you can’t just reach for an EQ knob for a particular channel. You
have to press a few buttons to set the EQ parameters.
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On the other hand, digital consoles have built-in effects and automated mixing. A sequencer circuit in the mixer remembers your mix so
you can recall it at a later time. One type of automated mixing is called
scene or snapshot automation. When you press the snapshot button, a
memory circuit in the mixer takes a “snapshot” of all the mixer settings
for later recall. Another type of automation is dynamic. Your mix moves
are stored in memory for later recall.
When you recall a mix, some mixers make the faders move into the
positions you set up. This feature is called “flying faders” or “motorized
faders.” Other mixers do not move the faders when you recall a mix. You
have to set them manually by looking at a display, which is a disadvantage. Motorized faders are more expensive but easier to use.
Digital Mixer Features
Look for the following features in digital mixers when making a buying
decision:
• Number of mic inputs: 2 to 16 or more.
• Number and type of digital inputs and outputs: S/PDIF, AES/EBU,
TDIF, ADAT
• Number and type of option card slots: extra I/O, DSP, sync, effects,
plug-ins
• Number of effects processors
• Ease of use
• Snapshot or dynamic automation
• Motorized or non-motorized faders
• Surround-sound monitoring
Software Mixer
Here’s another type of mixer. A software mixer (virtual mixer) is a simulated mixer you see on a computer screen. It exists only in your computer
as part of digital recording software. You control it with a mouse or with
a controller surface. Recordings made with this mixer are stored on your
hard drive.
In a software mixer, the input and output connectors are in an audio
interface (such as a sound card) that connects to the computer. This interface is 2-channel or multichannel. The software mixer works with effects
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that are either plug-ins (software) or external (hardware). Automation is
a standard feature.
For more on software mixers, see Chapter 13.
Controller Surface
A controller surface resembles a standalone mixer with faders and knobs.
It plugs into your computer’s USB or FireWire port and controls the software mixer. Some people prefer a controller because it is easier to use
than a mouse.
Now that you understand the typical features of mixers and mixing
consoles, you are ready to learn how to use them.
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12
OPERATING
THE MULTITRACK
RECORDER AND MIXER
Get your hands on those knobs. You’re going to operate a mixer as part
of a recording session. This will be a basic run-through. Detailed session
procedures are described in Chapter 15. Most of these procedures also
apply to operating a virtual mixer in a Digital Audio Workstation (DAW).
First recall the stages in making a recording:
1.
2.
3.
4.
5.
6.
Session preparation
Recording
Punching in
Overdubbing
Bouncing tracks
Mixdown
This chapter considers each stage in turn.
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Session Preparation
If you’re recording on hard drive, make sure you have enough drive
space for the project. Chapter 13 has simple equations and a table that
show how much space you need.
If you’re recording on a modular digital multitrack, fast-forward the
tape to the end and rewind to the top. This loosens the tape pack, distributes the tape lubricants more evenly, and aligns the tape with the tape
guides. Then format the tape from beginning to end. For efficiency, you
might want to format an entire box of videocassettes at once.
Plan your track assignments. Write a track sheet that tells
what instrument goes on which track. Note: If you assign multiple
instruments to the same track, you can’t separate their images in the
stereo stage. That is, you can’t pan them to different positions; all the
instruments on one track sound as if they’re occupying the same point in
space. If you’re recording 4-track, you may want to do a stereo mix of the
rhythm section on tracks 1 and 2; then overdub vocals and solos on tracks
3 and 4.
Studio setup for the musicians is covered in Chapter 15.
Recording
To start the process, first zero or neutralize the mixer by setting all the
controls to “off,” “flat,” or “zero.” This establishes a point of reference
and avoids surprises later on. Set all faders down.
If you have a separate mixer and multitrack recorder, you need to
make their meter readings match. To do this, play a steady tone into the
mixer to get a 0 reading on the meters for all channels. Then set the multitrack recorder’s record level (if any) to get 0 readings on all the tracks.
This works only if the mixer meters and recorder meters have the same
reaction speed (ballistics). If you are feeding the multitrack recorder from
your mixer’s insert jacks or direct-out jacks, you’ll need to watch the
recorder meters.
Some audio interfaces use on-screen volume controls to set recording levels. Some interfaces have level knobs for this purpose.
Suppose you’re ready to record a vocal or an acoustic instrument.
Place the microphone and plug it into a mic input. If you want to record
the audio output of a hardware synth or drum machine, connect a cable
between the instrument’s output and a line input on the mixer.
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Attach a “scribble strip” of masking tape or white removable tape
along the bottom of the faders, and label each fader according to what
instrument you plugged into that input. Some consoles and software
mixers have scribble strips that you can type on.
Set the input selector (if any) to Mic or Line depending on what is
plugged into each input.
Plug in headphones to hear what you’re recording. Turn up the
headphone volume control. Or, if you’re in a control room and the musicians are in a studio, turn up the monitor level to listen over the monitor
loudspeakers. On a hardware mixer, set the MONITOR SELECT switch
to hear the signal you’re recording, and turn up the musicians’ cue mix.
Set the master faders about three-quarters of the way up, at 0, or
within the shaded portion of fader travel. This is called design center. Do
the same for the input fader(s) in use (Figure 12.1). These settings give
the best compromise between noise and distortion.
Assign Inputs to Tracks
If your equipment wiring is mics > mixer > insert sends > track inputs,
your inputs are already assigned. Input 1 goes to track 1; input 2 goes to
tracks 2, and so on.
If you’re using a computer DAW, select the input source for each
track. For example, you might set track 5’s input to channel 5 in your
audio interface. Then, whatever is plugged into interface channel 5 will
go to track 5. If your sound card has just 2 channels, set track 5’s input
to channel 1 or 2 in your audio interface, and likewise for the other tracks.
If your equipment wiring is mics > mixer > busses > track inputs,
assign each input signal to the desired output channel (bus) as specified
on your track sheet. Each bus is connected to the corresponding numbered track on the multitrack recorder. Note: If only one instrument is
assigned to a track, you can eliminate the noise of the console’s combining amplifier by patching the instrument’s signal directly to the recorder
track. To do that, locate the direct output jack (or the insert jack) of the
input module for that instrument and patch it to the desired track. Some
mixing boards also require pressing a Direct button on the input module.
Set Recording Levels
Now you’re ready to “get a level.” Have each instrument play the loudest
part of the music, one at a time or all at once. For each input signal, set
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Practical Recording Techniques
Figure 12.1
Setting mixer faders at design center.
the TRIM control so the recording level is as high as possible without
causing distortion. While setting levels for a digital multitrack, peak each
track around -5 dBFS (-5 decibels Full Scale). This allows some headroom
for surprises. Also, musicians generally play louder during a performance than during a level check. Generally keep the maximum level
around -2 or -3 dBFS. If you exceed 0 dBFS you’ll hear digital clipping
which makes a loud click.
If you are mixing several instruments to one or two groups (as in a
drum submix), follow this procedure:
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1. Monitor the group(s).
2. Set its submaster fader (group fader) to design center.
3. Set the submix balances, panning, and recording level with the input
faders.
4. Fine-tune each submix level with the submaster fader.
Set EQ
Although it’s common to record flat (without EQ), you may want to apply
equalization at this point to each instrument heard individually. Filter out
frequencies above and below the range of the instrument. However, don’t
spend too much time on EQ until all the instruments are mixed together.
The EQ that sounds right on a soloed instrument may not sound right
when all the instruments are heard together. In creating the desired tonal
balance, use EQ as a last resort after trying different mics and mic placements. You also can apply EQ during playback or mixdown. This may be
preferable because EQ applied when recording cannot always be undone
if you’re unhappy with it.
Recording
Next, set the track(s) you want to record to “record ready” mode. Now
start recording. Write down the counter time for this take. “Slate” the
recording: record the name of the tune and the take number. Then record
a two-measure count-off. This is done to set the tempo for overdubs. For
example, if the time signature is 4/4, you say, “1, 2, 3, 4, 1, 2, (rest) (rest).”
The rests are silent beats. You need some silence before the song starts to
make editing easier later on. A DAW has a built-in metronome that can
be used for count-offs.
Playback
After recording the track, go to the beginning of the song using the returnto-zero or locate function. If necessary, set the monitor selector to “track,”
or “mix,” and play back the recording to check the performance and
sound quality. You can set a rough mix with the monitor mix (aux) knobs.
If your multitrack is patched to the insert jacks, use the faders, pan pots,
EQ, and aux knobs to set a rough mix.
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Get or write a sheet of the song’s arrangement. It shows the lyrics,
verses, choruses, bridge, and so on. Play the song and set a locate point
at the start of each verse and chorus. That way, when the musician says
“Let’s fix that flat note at the end of the second chorus,” you can go
instantly to that part of the song.
Overdubbing
After your first track is recorded with a good performance, you might
want to add more musical parts. This procedure is called overdubbing.
When you overdub, the musician listens to tracks already recorded, and
records a new part on an unused track.
Ready to overdub? Here’s what to do:
1. Turn off the control room speakers and listen on headphones.
2. Set up a headphone monitor mix of the recorded tracks. Some mixers
use the aux knobs for this. If your multitrack recorder is connected
to the mixer’s insert jacks, monitor the stereo mix, and set up a mix
with the channel faders.
3. Plug in the mic or direct box for the instrument or vocal you want
to record. Assign it to an unused track. Turn up its fader to design
center (the 0 point about three-quarters of the way up).
4. Set up your multitrack to monitor the playback of recorded tracks
and the input signal of the instrument or vocal you want to record.
In some DAWs this function is called “echo input monitor.” If your
mics and DAW output are plugged into a mixer, disable “echo input
monitor” because you will be monitoring all signals through the
mixer.
5. Have the musician play or sing. Can you hear the signal in the
phones? Set the recording level using the trim (gain) control for that
mic’s channel. If you are using a DAW and you hear a lot of latency
(delay) in the musician’s signal as heard over headphones, decrease
the latency setting in software. To prevent latency, you might want
to monitor the output of your hardware mixer instead. Feed your
audio interface output into the mixer, and listen to the recorded
tracks that way.
6. Play the recording. As the musician plays or sings along, set up a
good mix of the recorded tracks and the live instrument you’re going
to record. Ask the musician if he is hearing what he needs to hear.
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Change the mix if needed. Some musicians want to hear effects
when they overdub; some want it dry. If you’re overdubbing backup
vocals one at a time, often it helps to remove certain other vocals
from the headphone mix.
7. When you’re ready to record the new part, go to a point about 10
seconds before the part of the song where the musician plays. Set
the recorded tracks to SAFE and set the track you’re recording on to
RECORD READY.
8. Before you hit that RECORD button, stop! Are you recording on the
correct track(s)? Are you going to accidentally erase any tracks?
Double-check your track sheet, and make sure the record-enable
buttons are on only for the tracks that are safe to record over.
9. Start recording and have the musician play along with the tracks. If
the musician makes a mistake, you can re-record or punch-in the
new part without affecting the parts already on tape.
Punching-In
Punching-in is used to fix mistakes in a recorded performance, or to
record a musical part in segments. A punch is also called an insert. You
enable record mode on a track, play the multitrack recording, then
“punch” or press the record button at the right spot, record a new part,
then punch-out of record mode.
Some musicians record the same musical part over and over until
the part is perfect. This process is tedious, but you have to pay attention.
You need to be aware of where you are in the song at all times, and not
erase anything you want to keep.
Some musicians like to record a performance a phrase at a time, perfecting each phrase as they go. Others record a complete take, then go
back and fix the weak parts.
To do a punch-in, grab your song-arrangement sheet and follow
these steps:
1. Go to a point about 10 seconds before the point where you want to
start recording. Note the counter time and write it down. Also enter
a memory location point there if your recorder can do that.
2. Play the song to the musician over headphones. The musician plays
along to practice the part. Write down the tape counter times where
you want to punch-in and punch-out. Otherwise you might erase a
good take.
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Practical Recording Techniques
3. Finally you’re ready to record. Before you hit that RECORD button,
stop! Tell the musician what you’re going to do so there’s no chance
of a mistake. Be very clear. For example, “I’m recording your keyboard part on two new tracks.” Or, “I’m punching-in over your old
performance—is that what you wanted?”
4. Okay, ready to go. Play the recording. During a rest or pause in the
music just before the part needing correction, punch-in the record
button (or use a footswitch). Have the musician record the new part,
and punch-out right away. You don’t want to erase the rest of the
track!
5. Press LOCATE to go to the location point you set, about 10 seconds
before the punch. Play the recording to see if the punch was okay.
If necessary, you can re-record the punch. After you go to the locate
point, notice whether the musician wants to practice the part. Don’t
redo the punch until he or she is ready.
Some multitrack recorders have an autopunch function. You set the
punch-in and punch-out points into the machine’s memory. As the
recording plays, the recorder automatically goes into and out of record
mode at those points. Some recorders can loop repeatedly between those
two points.
Composite Tracks
If several open tracks are available, you can record a solo performance in
several takes, each on a separate track or virtual track. Then combine the
best parts of each track into a single track. Use only that track in the final
mix, and you’ll hear the best parts of all the takes in succession. This is
called “recording composite tracks” or “comping.” Here’s an example of
comping vocal tracks with a multitrack recorder and mixer:
1. Suppose you have four takes of a vocal recorded on tracks 10, 11, 12,
and 13. Solo each track, and mark on the lyric sheet which tracks
have the best performance of each section. For example, you might
prefer track 13 on Verse 1, track 10 on Chorus 2, and so on.
2. Assign all the vocal tracks to an open track, which we’ll call the
comp track. Match their levels.
3. Start recording on the comp track.
4. As the song plays, mute and unmute the tracks to copy the best performances to the comp track. To do that, you can stop the recorder
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between sections, change the mute settings, and record a section at
a time.
5. Once you’re happy with the comp track, you can erase or archive
the original tracks.
Comping with a DAW is even easier. Pick the best overall track, then copy
and paste good sections from other tracks into the best track.
Some recorders have virtual tracks (explained in Chapter 9). They
let you comp a performance with virtual tracks rather than real tracks.
Getting More Tracks
What if you want to overdub more parts, but all the tracks are full?
With care, you can punch-in more instruments by recording them in the
pauses on recorded tracks. For example, suppose all the tracks are full
but you want to add a cymbal crash at the beginning of the chorus. Find
a track that has a pause at that moment, and punch in the cymbal crash
there.
Here’s another way to free up tracks. Suppose that one track is
mostly blank except for a short riff at certain points in the song. Using a
patch cord (or using cut-and-paste in a DAW), copy that riff to a blank
area in another recorded track at exactly the same point in time. Then you
can erase the first track and record a new part on it.
As an alternative, you can bounce tracks—mix several tracks to one
or two open tracks, and record the mix on that track. Then you can erase
the original tracks, freeing them for more overdubs. Bouncing procedures
are in the instruction manual for your recorder or software.
Flying In
Suppose you have a multitrack recording of a pop song. One of the tracks
is vocals. During the first chorus, the vocals sound great, but during the
second chorus, the vocals are out of tune. So you want to copy the vocal
track from the first chorus to the second. If you’re using a DAW or harddisk recorder, you can use the cut-and-paste editing function.
If you’re using a Modular Digital Multitrack (MDM), copying parts
can be done by a process called flying in. You copy the first chorus on the
vocal track to an external DAW or sampler, then fly-in (copy) the external recording back to the multitrack where the second chorus would be.
The fly-in part must stay in sync with the other tracks.
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Practical Recording Techniques
Here’s another use for a fly-in. You give a keyboard player a CD-R
of a song you recorded. The keyboardist takes the song home, figures out
a keyboard part, and records it on another CD-R while listening to the
song. He or she sends the part to you, and you fly it into the multitrack
recording, or rip the CD track to a wave file and import it.
Here are the steps to do a fly-in:
1. On the multitrack recorder, find the track you want to copy. Connect
its output to a DAW audio interface input or sampler input.
2. Play the multitrack recording and copy the part to the DAW or
sampler. If the part you want to fly-in is already on CD-R, DAT, or
MiniDisc, copy it to your DAW or sampler.
3. Connect the DAW or sampler output to the input of the track on
which you want to record the fly-in.
4. Locate the multitrack recorder to a point a few seconds before where
you want to fly-in the part.
5. Start recording on the correct track. While listening to the song play,
press PLAY on the DAW, or trigger the sample, so that the flown-in
part starts at the right time. Practice this until the timing is correct.
The tempos should match if you recorded to a click track.
Drum Replacement
Suppose you’ve recorded the drum tracks, but you don’t like the sound
of them. Maybe the kick drum is too flabby, and no amount of EQ or
gating seems to help. You might try a technique called drum replacement.
You take recorded drum tracks and replace them with drum samples generated by a drum machine, sampler, or sound module. Here are the steps:
1. Select the desired drum sound in the sampler.
2. Feed the audio from the drum track into the sampler’s trigger input.
3. Connect the sampler’s audio output to an unused track input on
your recorder.
4. Play the original drum track and record the sampler’s output signal
on the unused track. When each drum hit triggers the sampler, it
instantly plays its internal drum sample.
In this way you can replace individual drum tracks or an entire kit. You
can also mix the samples with the original tracks to get a bigger drum
sound.
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In a MIDI/Digital Audio recording program, you can replace an
audio drum track with a MIDI track that plays drum samples. First, set
up a MIDI track with a drum sample ready to play (for details, see
Chapter 16). Then use one of these methods:
Method 1: In the MIDI drum track you want to create, open the MIDI
sequencer editing screen. Draw a note for each drum hit on the
correct beats.
Method 2: Start recording on the MIDI drum track, and tap your
MIDI controller key in sync with the playback of the audio drum
track.
Method 3: Select the audio drum track, then enable the “Extract
Rhythm” or “Extract Beat” feature, if any. Copy and paste the
extracted MIDI beats to the MIDI drum-sample track.
Mute the original audio drum track and press PLAY. You should
hear the replacement drum sample playing.
Mixdown
After all your tracks are recorded (maybe with some bouncing), it’s time
to mix or combine them to 2-track stereo. You will use the mixer faders
to control the relative volumes of the instruments, use panning to set their
stereo position, use EQ to adjust their tone quality, and use the aux knobs
to control effects.
Set Up the Mixer and Recorders
To prepare for a mixdown, first locate the mixer jacks for output channels 1 and 2 (they might be called bus 1 and 2, or stereo mix bus). Plug
these outputs into the line inputs of your 2-track recorder (Figure 12.2).
If you’re using a DAW, omit this step.
What if you’re synching an external MIDI sequencer to your audio
recorder? Use a separate line mixer to combine your audio mixer’s output
with the sequencer’s audio output. Or if your audio mixer has enough
input channels, plug the sequencer audio outputs into the audio mixer.
Mix the audio tracks with the MIDI tracks.
Once connections are made, you can begin. Set all the mixer controls
to “off,” “zero,” or “flat.” You should start from ground zero in building
a mix.
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Practical Recording Techniques
Figure 12.2
Connections for mixdown.
Tape a strip of paper or masking tape along the front of the mixer
to write which instrument(s) each fader affects. Keep this strip with the
multitrack tape for use each time you play it. Or type in this information
in your DAW or mixing console.
If necessary, set the input-selector switches on the mixer to “track”
because you’ll be mixing down the multitrack recording. Monitor the 2track stereo mix bus. These steps are unnecessary if you are using a DAW.
For starters, put the master faders at design center (about three-quarters of the way up, at the shaded portion of fader travel). This sets the
mixer gain structure for the best compromise between noise and
headroom.
Erase Unwanted Material
Mixing will be a lot easier if you first erase noises before and after each
song, and within each track.
Play the multitrack recording and listen to each track alone. Erase
unwanted sounds, outtakes, and entire segments that don’t add to the
song. To avoid mistakes, it’s best to do this while the musicians are
around.
What if a noise occurs just before the musician starts playing? When
you erase the noise, you might erase the beginning of the performance.
It might be safer to mute the track during mixdown and then unmute it
just before the musician plays. Or you could set up an automatic punchin/-out at the correct times to erase the noise.
Removing noises with a DAW is easier. Look at a recorded track’s
waveform to see where the music and silences are. Divide the track into
music clips and silent clips (segments), and delete the silent ones. This
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removes the noises that are in the silent (unplayed) portions of the track.
If you recorded a track in separate segments or clips, trim or slip-edit the
start and end points of each clip to remove noises.
Panning
You need to pan the tracks before doing the mix, because the loudness of
a track depends on where it’s panned. Assign each track to busses 1 and
2 (or the stereo mix bus), and use the pan pots to place each track where
desired between your stereo speakers. Typically the bass, snare, kick
drum, and vocals go to center; guitars can be panned left or right, and
stereo keyboards and drum overheads go left and right.
Pan tracks to many points between the monitors: left, half-left,
center, half-right, right. Try to achieve a stereo stage that is well balanced
either side of center. For clarity, pan to opposite sides any instruments
that cover the same frequency range.
You may want some tracks to be unlocalized. Harmony singers and
strings should be spread out rather than appearing as point sources.
Stereo keyboard sounds can wander between speakers. You could fatten
a lead-guitar solo by panning it left, and panning the solo delayed to the
right. (This delay might come from a distant room mic you used while
recording, or from copying and sliding a track a few milliseconds in a
DAW.) Pan doubled vocals left and right for a spacious effect.
Consider creating some front-to-back depth. Leave some instruments dry so they sound close; add reverb to others so they sound farther
away.
If you want the stereo imaging to be realistic (say, for a jazz combo),
then pan the instruments to simulate a band as viewed from the audience. If you’re sitting in an audience listening to a jazz quartet, you might
hear drums on the left, piano on the right, bass in the middle, and sax
slightly right. The drums and piano are not point sources, but are somewhat spread out. If spatial realism is the goal, you should hear the same
ensemble layout between your speakers. In most rock recordings, the
piano and drums are spread all the way between speakers—interesting
but unrealistic.
Pan-potted mono tracks often sound artificial; each instrument
sounds isolated in its own little space. It helps to add some stereo reverb.
It surrounds the instruments and “glues” them together.
When you monitor the mix in mono, you’ll likely hear center
channel buildup. Instruments in the center of the stereo stage will sound
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louder in mono than they did in stereo, so the mix balance will change
in mono. To prevent this, note which tracks are panned hard left or right,
and bring them a little toward the center: 9 and 3 o’clock on the pan
knobs.
Compression
Sometimes the lead vocal track might be too loud or too quiet relative to
the instruments because vocals have a wider dynamic range than instruments. You can control this by running the vocal track through a compressor. It will keep the loudness of the vocal more constant, making it
easier to hear throughout the mix. Patch the compressor into the insert
jack(s) of the vocal input module, or between the vocal track output and
the mixer input. Set the desired amount of compression (typically 2 : 1
ratio, -10-dB threshold). It’s also common to compress the kick drum and
bass. (For more information, see Chapter 10.)
Set a Balance
Now comes the fun part. The mixdown is one of the most creative parts
of recording. Here are some tips to help your mixes sound terrific.
Before doing a mix, tune up your ears. Play over your monitors some
CDs whose sound you admire. This helps you get used to a commercial
balance of the highs, mids, and lows.
Choose a CD with tunes like those you’re recording. Check out the
production. How is the balance set? How about EQ, effects, and sonic
surprises? Try to figure out what techniques were used to create those
sounds, and duplicate them. Of course, you might prefer to break new
ground.
Using the input faders, adjust the volume of each track for a pleasing balance among instruments and vocals. You should be able to hear
each instrument clearly. Some mixing consoles have trim knobs that set
the playback gain of the multitrack recorder tracks. In that case, set all
faders in use to design center, and adjust the trims to get a rough mix.
Here’s one way to build the mix. Make all the instruments and
vocals equally loud. Then turn up the most important tracks and turn
down background instruments. Or, bring up one track at a time and blend
it with the other tracks. For example, first bring up the kick drum to about
-10 dB, then add bass and balance the two together. Next add drums and
set a balance. Then add guitars, keyboards, and finally vocals.
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In a ballad, the lead vocal is usually on top. You might set the soloed
lead-vocal level to peak at -5 dB. Bring up the monitor level so that the
vocal is as loud as you like to hear it, then leave the monitor level alone.
Bring in the other tracks one at a time and mix them relative to the vocal
track.
When the mix is right, everything can be heard clearly, yet nothing sticks out too much. The most important instruments or voices are
loudest; less important parts are in the background. In a typical rock mix,
the snare is loudest, and the kick is nearly as loud. The lead vocal is next
in level. Note that there’s a wide latitude for musical interpretation and
personal taste in making a mix.
Sometimes you don’t want everything to be clearly heard. Once in
a while, you might mix in certain tracks very subtly for a subconscious
effect.
It’s a good idea to monitor around 85 dBSPL. If you monitor louder,
the bass and treble will be weak when the mix is played softly.
To test your mix, occasionally play the monitors very quietly and see
if you can hear everything. Switch from large monitors to small, and
make sure nothing is missing.
Set EQ
Next, set EQ for the tonal balance you want on each track. If a track
sounds too dull, turn up the highs or add an enhancer. If a track sounds
too bassy, turn down the lows, and so on. Cymbals should sound crisp
and distinct, but not sizzly or harsh; kick drum and bass should sound
deep, but not overwhelming or muddy. Be sure the bass is recorded with
enough edge or harmonics to be audible on small speakers.
You’ll need to readjust the mix balances after adding EQ. The EQ
that sounds right on a soloed track seldom sounds right when all the
tracks are mixed together. So make EQ decisions when you have the complete mix happening.
In pop-music recordings, the tone quality or timbre of instruments
does not have to be natural. Still, many listeners want to hear a realistic
timbre from acoustic instruments, such as the guitar, flute, sax, or piano.
The overall tonal balance of the mix shouldn’t be bassy or trebly.
That is, the perceived spectrum should not emphasize lows or highs. You
should hear the low bass, mid-bass, midrange, upper midrange, and
highs roughly in equal proportions. Frequency bands that are too loud
can tire your ears.
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When your mix is almost done, switch between your mix and a commercial CD to see whether you’re competitive. If the tonal balance of your
mix matches a commercial CD, you know your mix will translate to the
real world. This works regardless of what monitors you use. An effective
tool for this purpose is Harmonic Balances (www.har-bal.com).
Add Effects
With the balances and EQ roughed in, it’s time to add effects. You might
want to plug in a reverb or delay to add spaciousness to the sound (see
Chapter 10). This device connects between your mixer’s aux-send and
aux-return jacks (or aux-send and bus-in jacks).
Find the AUX RETURN or BUS IN controls (if any), set them half of
the way up, and pan them hard left and right. Using the AUX knobs
on the mixer, adjust the amount of delay or reverb for each track as
desired.
Too much effects and reverb can muddy the mix. You might turn
up the reverb only on a few instruments or vocals. Once you have the
reverb set, try turning it down gradually and see how little you can get
by with.
The producer of a recording is the musical director and decides how
the mix should sound. The producer might be the band members or yourself. Ask to hear recordings having the kind of sounds the producer
desires. Try to figure out what techniques were used to create those
sounds.
Also try to translate the producer’s sound-quality descriptions into
control settings. If the producer asks for a “warmer” sound on a particular instrument, turn up the low frequencies. If the lead guitar needs to
be “fatter,” try a stereo chorus on the guitar track. If the producer wants
the vocal to be more “spacious,” try adding reverb, and so on. CD track
39 demonstrates a mixdown.
Set Levels
Set the overall recording level as you’re mixing. To maintain the correct
gain staging, keep the master faders at design center. Then adjust all the
input faders by the same amount so your stereo output level peaks
around -5 dB. You can touch up the master faders a few decibels if necessary. Don’t exceed a 0-dB recording level if you’re recording to a digital
medium.
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Judging the Mix
When you mix, your attention scans the inputs. Listen briefly to each
instrument in turn and to the mix as a whole. If you hear something you
don’t like, fix it. Is the vocal too tubby? Roll off the bass on the vocal track.
Is the kick drum too quiet? Turn it up. Is the lead-guitar solo too dead?
Turn up its effects send.
Check the mix while listening from another room, where the lows
and highs are weakened. Is the balance still good?
The mix must be appropriate for the style of music. For example, a
mix that’s right for rock music usually won’t work for folk music or
acoustic jazz. Rock mixes typically have lots of production EQ, compression, and effects; and the drums are way up front. In contrast, folk or
acoustic jazz is usually mixed with no effects other than slight reverb, and
the instruments and vocals sound natural. A rock guitar typically sounds
bright and distorted; a straight-ahead jazz guitar usually sounds mellow
and clean.
Suppose you are mixing a pop song, and you’re aiming for a realistic, natural sound. Listen to the reproduced instruments and try to make
them sound as if they’re really playing in front of you. That is, instead of
trying to make a pleasant mix or a sonically interesting recording, try
to control the sound you hear to simulate real instruments—to make
them believable. To do this you must be familiar with the sound of real
instruments.
It’s like an artist trying to draw a still-life as realistically as possible.
The artist compares the drawing to the real object, notes the difference,
and then modifies the drawing to reduce the difference.
When you’re striving for a natural sound, compare the recorded
instrument with your memory of the real thing. How does it sound
different? Turn the appropriate knob on the console that reduces the
difference.
Alternatively, when you’re mixing, imagine that you’re creating a
sonic experience between the monitor speakers, rather than just reproducing instruments. Sometimes you don’t want a recording to sound too
realistic. If a recording is very accurate, it sounds like musical instruments, rather than just music itself.
This approach contradicts the basic edict of high fidelity—to
reproduce the original performance as it sounded in the original
environment. Some songs seem to require unreal sounds. That way,
you don’t connect the sounds you hear with physical instruments,
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but with the music behind the instruments—the composer’s dream or
vision.
Here’s one way to reproduce pure music rather than reproducing
instruments playing in a room: Mike closely or record direct to avoid
picking up studio ambience. Then add reverb. Also add EQ, doubletracking, and effects to make the instrument or voice slightly unreal. The
idea is to make a production, rather than a documentation—a record,
rather than a recording.
Try to convey the musician’s intentions through the recorded sound
quality. If the musician has a loving, soft message, translate that into a
warm, smooth tone quality. Add a little mid-bass or slightly reduce the
highs. If the musical composition suggests grandeur or space, add reverberation with a long decay time. Ask the musicians what they are trying
to express through the music, and try to express that through the sound
production as well.
Try to keep the mix clean and clear. A clean mix is uncluttered; not
too many parts play at once. It helps to arrange the music so that similar
parts don’t overlap. Usually, the fewer the instruments, the clearer the
sound. Mix selectively, so that not too many instruments are heard at the
same time. Have guitar licks fill in the holes between vocal phrases, rather
than playing on top of the vocals.
In a clear-sounding recording, instruments do not “crowd” or
mask each other’s sound. They are separate and distinct. Clarity
arises when instruments occupy different areas of the frequency spectrum. For example, the bass provides lows; keyboards might emphasize
mid-bass; lead guitar may provide upper mids, and cymbals fill in the
highs.
Often the rhythm guitar occupies the same frequency range as the
piano, so they tend to mask each other’s sound. You can aid clarity by
equalizing them differently. Boost the guitar at, say, 3 kHz, and boost the
piano around 10 kHz. Or pan them to opposite sides.
More on judging sound quality is seen in Chapter 14.
Changes During the Mix
It’s rare to do a mix in which you set the faders and leave them there.
Often you need to mute tracks, change fader levels, or change EQ during
a mix.
To reduce background noise, mute all tracks that have nothing
playing at the moment. That is, if there is a long silence during a track,
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mute that silent portion. Unmute these tracks just before their instruments start playing. Mute unrecorded tracks as well.
Level changes during the mix should be subtle, or else instruments
will “jump out” for a solo and “fall back in” afterwards. Set faders to
preset positions during pauses in the music. Nothing sounds more amateurish than a solo that starts too quietly then comes up as it plays. You
can hear the engineer working the fader. If you need to reduce the level
of a loud passage, do so at the end of the preceding soft passage before
the loud one begins.
If you need to change fader levels during the mix, and you don’t
have automation, you might mark these levels next to each fader on a
thin piece of tape. Make a cue sheet that notes the mixer changes at
various tape-counter times. For example:
0 : 15 Unmute vocal
1 : 10 Lead solo -5
1 : 49 Lead -10
2 : 42 Synth EQ +6 at 12 K
3 : 05 Start fade, out by 3 : 15.
What if you want the sound of an instrument to change drastically
during a song, but there are too many mixer changes to handle at once?
You can do this by multing and muting. Here’s what to do:
Suppose you want a track to have a radically different level, EQ,
and effects during the chorus. Using a Y-cord or a mult on a patch
bay, connect that track to two mixer channels—say, channels 5 and 6.
If you’re using a DAW, copy track 5 to track 6. On channel 5, set the
level, EQ, and aux sends as you want them to be for most of the song.
On channel 6, set those controls as you want them to be for the
chorus.
When you’re ready to mix, mute channel 6. Play the song and mix
it. When the chorus comes up, unmute channel 6 and mute channel 5.
The sound will change during the chorus. In a DAW you make this
change part of an automated mix.
Record the Mix
When you’re happy with the mix and recording levels, record the mix on
your 2-track recorder: DAT, CD-R, or hard drive. If you will record the
mixes on DAT, put in a blank DAT tape and exercise it: fast-forward to
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the end and rewind to the top. You might want to clean the tape path
with a cleaning cassette, but usually only if the DAT is producing errors.
Keep a log noting the start and stop times for each song. You’ll use these
times when you’re ready to edit. If you’re using a DAW, export or save
the mix as a new sound file.
If the mix is very difficult, you can record it a section at a time, and
then edit the sections together.
To fade out the end of the tune, pull down the master faders slowly
and smoothly. Try to have the music faded out by the end of a musical
phrase. The slower the song, the slower the fade should be. The musical
meaning of a fade is something like, “This song is continuing to groove,
but the band is leaving on a slow train.” You might want to postpone
fades until mastering, which is done in a DAW.
The mixdown is complete. If you’re using a standalone 2-track
recorder, leave it running for a few seconds—make a blank space so you
don’t accidentally erase the end of the mix you just did with subsequent
recordings. Play back the mix to listen for dropouts and errors. You might
record several different mixes of one song, then choose the best mix. It’s
common to record a mix with the lead vocal up 1 dB, and another with
the lead vocal down 1 dB.
Repeat these mixdown procedures for the rest of the good takes,
leaving about 20 seconds of silence between each mix recording. Give
your ears a rest every few hours! Otherwise, your hearing loses highs and
you can’t make correct judgments.
After a few days, listen to the mix on a variety of systems—car
speakers, a boom box, a home system. The time lapse between mixdown
and listening will allow you to hear with fresh ears. Do you want to
change anything? If so, make it right. You’ll end up with a mix to be
proud of.
If you lack good multitrack recordings with which to practice
mixing, go to www.raw-tracks.com. There you can download individual
tracks in wav or mp3 format, or purchase a CD of raw tracks.
Summary
The following are summaries of the procedures for recording, overdubbing, and mixdown. Use these steps for easy reference.
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Recording
1. Turn up the headphone or monitor volume control. Monitor the aux
bus that you’re using for the monitor mix. If your multitrack is wired
to the insert jacks, monitor the stereo bus instead. If you’re using a
DAW, monitoring is automatic.
2. Assign instruments to tracks. To record one instrument per track,
connect its direct-out (or insert send) to a track input. If you’re using
a DAW, select each track and assign it an input signal from your
audio interface.
3. Turn up the input faders, submaster, and master faders to design
center (the shaded portion of fader travel, about three-quarters of
the way up).
4. Adjust the input attenuators (trim) to set submixes and recording
levels. If you’re recording with a DAW, use the volume controls of
the audio interface (they might be a software application).
5. Set the monitor/cue mix.
6. Record onto the multitrack recorder.
Overdubbing
1. Assign the instruments or vocals to be recorded to open tracks. An
open track is blank or has already been bounced.
2. Turn up the monitor/cue system.
3. Turn up the submasters and master to design center.
4. Play the multitrack recording and set up a cue mix of the alreadyrecorded tracks.
5. While a musician is playing, adjust the input attenuation and recording level.
6. Set the monitor/cue mix to include the sound of the instrument or
vocal being added.
7. Record the new parts on open tracks.
8. Punch in and comp tracks as needed.
Mixdown
1. If necessary, set the input selectors to accept the multitrack recorder
output signals.
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2. Monitor busses 1 and 2 (or the stereo mix bus). Monitoring is automatic with a DAW.
3. Assign tracks to busses 1 and 2 (or the stereo mix bus).
4. Turn up the master fader to design center. In some mixers, the submasters should also be up.
5. Set preliminary panning.
6. Set a rough mix with the input faders. Maybe start with all faders at
-12 dB, then adjust from there.
7. Set equalization and effects.
8. Perfect the mix and set recording levels. Set up automation if your
system has it (described next).
9. Record onto the 2-track recorder. If you have a DAW, export or save
the mix as a new wave file.
Automated Mixing
A multitrack mixdown is often a complicated procedure. It can be difficult to change the mixer settings correctly at all the right times. So you
might want to use automated mixing—have a MIDI sequencer remember and set the changes for you.
As you mix a song, you might adjust the mixer controls several
times. For example, raise the piano’s volume during a solo, then drop
it back down. Mute a track to reduce noise during pauses in the performance. An automated mixing system can remember your mix moves,
and later recall and reset them accordingly each time you play back
the mix. You can even overdub mix moves; for example, do the vocalfader moves on the first pass, drum moves on the second pass, and
so on. You also can punch-in fader moves to correct them. Effects
changes can be automated as well in some units. Automated mixing
is a feature in digital mixers, software DAWs, and many hard-disk
recorder-mixers.
Automated mixing has many advantages. With it you can:
• Perform complicated mixes without errors
• Fine-tune the mix moves
• Recall mixes weeks or months after storing them, without having to
reset the mixer manually each time
• Listen to the mix without the distraction of having to adjust faders
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Types of Automation Systems
Three types of automation systems are
1. Automated mixer with non-motorized faders
2. Automated mixer with motorized faders (Flying Faders)
3. Recording software with automated mixing
Each of these is worth a closer look.
Automated Mixer with Non-Motorized Faders
Suppose you have mixer or controller surface with non-motorized faders.
The mix is playing and you are adjusting the faders. As you set the position of each fader, this action produces a MIDI signal that is recorded by
a sequencer. This sequencer is either built into the mixer or is external.
When the mix plays back, so does the sequence of mix moves. MIDI
signals from the sequencer set the volume level for each channel. This is
done by varying the gain of a voltage controlled amplifier (VCA) or digitally controlled amplifier (DCA) in each channel. Because the faders do
not move as the mix plays back, the fader positions do not represent the
mix you are hearing.
Automated Mixer with Motorized Faders
This system works as follows. First, you adjust the faders to set up a mix.
This generates MIDI signals that are recorded by a sequencer. When you
play back the mix, the sequencer makes the motorized faders move up
and down as if controlled by a ghost, matching your mix moves. The position of the mixer faders show the mix levels. VCAs are not needed, which
is a benefit because VCAs can degrade the audio slightly.
Recording Software with Automated Mixing
Chapter 13 defines a DAW as a personal computer running audio recording software. A sound card or I/O box plugged into the computer has
connectors to get audio into and out of the computer.
Once the musical tracks are recorded and edited, you’re ready to
mix. The monitor screen shows virtual faders that you adjust with a
mouse or with a controller surface. A software sequencer remembers your
mix moves, EQ settings, and so on, and does an automated mix during
playback.
In most DAWs, a fader envelope appears on each track. This envelope is a graph of a track’s fader setting versus time. You might prefer to
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automate the mix by tweaking the fader envelope instead of moving the
faders.
As we said earlier, a MIDI/audio recording program includes both
digital audio tracks and sequencer tracks. The audio track levels are automated by adjusting their gain; the MIDI tracks are automated by adjusting their MIDI volume or key-velocity scaling.
Lower cost programs let you control volume only; higher cost programs let you control all parameters (EQ, panning, and effects). Some or
all of these parameters can be automated.
Snapshot versus Continuous Automation
Two types of automation are snapshot and continuous (dynamic). With
snapshot automation, you push a button to take a “snapshot” or “scene”
of the mixer settings. The sequencer stores the snapshot as the MIDI
program changes. To reset the mixer to any of these stored settings, you
punch-up the appropriate number (MIDI program change). Alternatively,
your sequencer/audio recording software can reset the mixer’s virtual
controls at the correct times as a song plays.
With continuous or dynamic automation, the sequencer records the
motion of the mixer controls—not just their position. Continuous
automation costs more than snapshot and consumes more memory, but
permits finer resolution of mix moves. Some digital mixers do both snapshot and continuous automation with their internal sequencer. Other
mixers require an external MIDI sequencer to record continuous automation moves.
Some automated mixers let you specify a fade time between snapshots. When the sequencer changes from one snapshot to the next, the
sequencer fades or adjusts the control settings gradually between the two
snapshots. This acts like continuous or dynamic automation.
Automated Mixing Procedure
Here is a suggested order of steps in doing an automated mix:
1. Set up a rough mix manually. You might prefer to start with a song
section where all the instruments are playing.
2. Record the mutes. Mute tracks that aren’t being used, or that don’t
add to the arrangement. For example, a chorus might sound better
without the horns. Unmute each muted track just before you want
it to be heard.
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12
3. Record the fader moves. For example, turn up the guitar during the
solo, turn up the toms during the fills, turn down the background
vocals when they get too loud. Save your changes often.
4. Record the effects changes. You might bring up the chorusing on the
acoustic guitar during the bridge, and so on.
5. Sit back and listen to the mix. Is there anything you want to change?
Another way to do an automated mix is with snapshots. At several points
in the song where you need mutes or fader changes, set the mute or fader
level on the appropriate track and take a snapshot. This can be done in
a hardware mixer or a software DAW.
Suppose you want a track’s sound to change radically during the
song. Maybe you want the lead guitar to change level, EQ, and reverb
during the chorus. Here’s a slick way to do it: Using a Y-cable or patchbay mult, split the guitar track’s signal to two adjacent channels on your
mixer—say, channels 5 and 6. Channel 5 is set up the way you want it for
most of the song. Channel 6 is set up with the EQ, level, and reverb you
want during the chorus. Mute channel 6 and start playing the song. When
the chorus comes up in the song, mute channel 5 and unmute channel 6.
Save this mute change. This technique also works with nonautomated
mixers. In a DAW, you can cut and paste the chorus from track 5 onto
track 6, which is set up with different EQ and effects than track 5.
Here is a “poor man’s” automation system suggested by producer/engineer Dave Aron. Suppose you are using a standalone digital
multitrack recorder and you have two empty tracks.
1. Connect your mixer’s stereo outputs to the inputs of those two
tracks.
2. Set up the mix at the beginning of the tune, and start recording the
mix on the empty tracks, as if you were recording to a 2-track
recorder.
3. When you come to a point in the song where the mix needs to be
changed, stop recording.
4. Rewind a few seconds, hit PLAY, and reset the faders as desired.
5. Again, rewind the tape a few seconds and hit PLAY. On the two mix
tracks, punch into record mode at the point where the mix changes.
6. Continue this process for all the changes in the mix, updating the
mix as you go.
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13
COMPUTER RECORDING
With recording software and a sound card, you can turn your computer
into a powerful digital recording studio. This Digital Audio Workstation
(DAW) lets you record dozens of audio tracks, edit them, add effects, do
a mixdown with automation, and burn a professional-quality CD—all in
your computer. The cost is only a few hundred dollars.
In addition to recording audio, most DAW software can act as a
sequencer by recording MIDI data. You can record, edit, and play both
audio and MIDI tracks in the same program.
Another function of a DAW is to edit tracks that were originally
recorded on a standalone multitrack recorder. You can transfer eight or
more tracks at once to your computer by using a sound card with Alesis
Lightpipe or Tascam TDIF connectors, or with an Alesis FirePort that
works with an Alesis HD24 hard-disk recorder.
A DAW has three parts (Figure 13.1):
1. A fast computer with lots of memory and a large hard drive.
2. An audio interface to get audio and MIDI into and out of your
computer.
3. Recording software.
You also need some powered monitor speakers, at least one mic, and
a mic preamp or mixer. Although you can use the mic input in a sound
card, it is likely to be low quality and noisy. You’ll get better sound with
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MONITOR
HARD
DRIVE
PCI SLOT, USB PORT,
OR FIREWIRE PORT
COMPUTER
KEYBOARD
ALESIS
FIREPORT
I/O INTERFACE
(BREAKOUT BOX)
SOUND CARD
MOUSE
CONTROLLER WITH I/O
AUDIO INTERFACES (CHOOSE ONE)
Figure 13.1
A computer DAW.
a separate mic preamp or mixer. Some optional extras are a control
surface and DSP cards. These are explained later under those headings.
Basic Operation
When you launch the recording software, you see simulated tracks and
recorder transport buttons such as fast-forward, rewind, record and play.
You also see a mixer with virtual controls: simulated faders, knobs,
buttons, and meters.
DAW software has several windows or views (Figure 13.2). You view
and manipulate the tracks in the Track window, do edits in the Track or
Edit window, and adjust mixer controls in the Mixer window. Each
window can be opened to fill the entire screen.
Recording and Playback
Here’s how the system works. Audio from your mixer or mic preamp
goes to the inputs on the audio interface, which converts the audio to
computer data and sends it to the computer. The software lets you record
this data on the computer’s hard drive. During playback, the recorded
data streams from the hard drive into the interface, which converts the
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Computer Recording
Figure 13.2
13
An example of DAW software windows.
data back into audio at the interface outputs. Monitor speakers connected
to those outputs play the audio.
Audio data on the hard drive is read by an electromagnetic head.
Because the head can be controlled to jump to any location on disk, it has
random access: it can instantly locate any part of the audio program. As
the head is jumping around, the data pieces it picks up are read into a
buffer memory, then read out at a constant rate.
The waveform of the recorded audio appears on your monitor
screen (Figure 13.3). You can zoom out to see the entire program, or zoom
in to see individual samples.
Like a multitrack tape recorder or hard-disk recorder, a DAW has
several tracks to record on. You might record a MIDI drum pattern on
track 1, a bass audio signal on track 2, guitar on 3, keys on 4 and 5, vocals
on 6, and so on. During playback those tracks mix or combine into a
stereo signal that plays through your audio interface.
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Practical Recording Techniques
Figure 13.3
A waveform editing screen (Source: Adobe Audition).
Editing
Editing is a major feature of all DAW programs. Listed below are some
editing functions you’ll find in most DAW recording software:
• Cut or Trim: Remove or truncate unwanted portions of the waveform or program. For example, cut out silent areas in each track to
reduce leakage and background noise. Delete audio glitches and
clicks.
• Cut and paste: Remove a section of a song and put it somewhere
else in the song. If you think the bridge section of a song should
come earlier, you can remove it from its current location and put it
where you want it.
• Copy and paste: For example, copy a chorus in a song and put it at
the measures where the chorus is repeated. Copy a track and paste
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it into a blank track with different EQ or processing. Or copy an intune note and paste it over an out-of-tune note (zoom-in to do this
with precision).
• Fade-in, fade-out: Do an automated fade (a gradual change in
volume).
• Crossfade: Fade out of one song while fading into another. Or crossfade across an edit point to make it sound smoother. A logarithmic
crossfade gives a more even volume level than a linear crossfade.
• Slip: You can slip tracks forward or backward in time, independent
of other tracks. You also can move single notes in time. If a note in
a bass track comes in too late, select the note and slide it or nudge
it to the left until it is on the beat. Or adjust the start times of sound
effects so they align with events in video clips.
• When mastering a program for CD, you can select entire songs and
move them around to change the order they will play in.
When you edit audio, you select a portion of the audio program, creating a clip or region. Examples of clips are an entire song, the chorus of
a song, a guitar track, a drum riff, or a single note. Using a mouse, you
can create a clip by marking its beginning and end points in the waveform. In Figure 13.3, a clip is selected and highlighted.
A clip is actually a pair of pointers to part of an audio file on your
hard drive. One pointer is the data address for the beginning of the clip,
and the other pointer is the address for the end of the clip. Rather than
containing audio data, clips tell the software which section(s) of the audio
file to play.
When you set up the sequence of clips in a mix, you’re telling the
hard-drive head which pointers to play in what order. Or when you
delete a clip, you’re telling the hard-drive head to skip the clip’s pointers during playback. If you copy an audio clip, the software does not
make copies of the audio file it points to—instead, it plays the same audio
file each time it sees a clip pointing to that file. Or when you split a clip
into parts and put them in a different order, the audio file itself is not
split. Instead, the software plays the sections of the audio file that the
clips point to, in the desired order.
These types of edits are called nondestructive edits. Only the pointers change; the data on disk is not changed or destroyed. Nondestructive
edits are not permanent. If you don’t like an edit, you can undo it and
try it again.
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Some types of edits or processing are destructive: they write over
the data on disk. However, some recording programs save the data before
you edit it. Then you can undo the change by reverting to the saved data.
Editing can create unusual effects. For instance, copy a syllable in a
vocal track and paste it several times to create stuttering. Suppose you
want to double a guitar that is in the left channel to make it stereo. Copy
the guitar track, paste it to another track, slide the pasted guitar track
to the right about 20 to 30 msec (which delays the guitar signal), and pan
the delayed guitar track to the right.
Mixdown
Once all your tracks are recorded (and maybe edited), it’s time for
mixdown. Here is the general procedure:
1. Adjust each on-screen fader with your mouse to set the level of each
track until you create a good balance among tracks.
2. Make selections with the mouse to add EQ, compression, and effects
to various tracks.
3. Set up automation so that the computer remembers your mix
settings and resets them the next time you play the mix.
4. Once your mix is perfected, export it to a stereo wave file or aiff file
on your hard drive.
5. Repeat steps 1 to 4 for all the songs in a demo or album.
6. Open a new project, and import the mixes into a stereo track. Put
the mixes in order with some silence between them.
7. Burn a CD of the finished mixes.
With this basic understanding, let’s take a closer look at DAW components: the computer, audio interface, and recording software.
The Computer
Either Mac or PC will give great results with audio software. Just be sure
that the software you want to use is compatible with your computer
platform.
In order to play a lot of tracks and effects in real time, you need a
computer with a fast central processing unit (CPU); lots of RAM; and
a large, fast hard drive. A minimum system would be a 2 GHz CPU,
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Table 13.1 Hard-Drive Storage Required for a 1-Hour Recording
No. of tracks
2
2
2
8
8
8
16
16
16
24
24
24
Bit depth
16
24
24
16
24
24
16
24
24
16
24
24
Sampling rate
Storage needed
44.1 kHz
44.1 kHz
96 kHz
44.1 kHz
44.1 kHz
96 kHz
44.1 kHz
44.1 kHz
96 kHz
44.1 kHz
44.1 kHz
96 kHz
606 MB
909 MB
1.9 GB
2.4 GB
3.6 GB
7.7 GB
4.8 GB
7.1 GB
15.4 GB
7.1 GB
10.7 GB
23.3 GB
512 MB RAM, and an 80-GB hard drive. Two hard drives are faster: one
for system files and programs, and another for audio data. The drive
should be capable of high sustained transfer rate (thruput). Current
ATA-100 or ATA-133 drives can sustain up to about 40 MB per second,
which is fast enough for multitrack recording.
Multitrack audio consumes a lot of disk storage space. Table 13.1
shows the amount of hard-drive space needed for a 1-hour recording with
various recording formats.
If you plan to record a 1-hour album with about four takes per song,
multiply the “Storage Needed” by four. In addition to the disk storage
for each song’s tracks, you will need about 30 to 200 MB per song mix,
and up to 750 MB for a CD album of the song mixes.
Audio Interfaces
Once you have a fast computer with a large hard drive, you need a way
to get audio signals into and out of the computer. An audio interface does
the job. Four types of interface are listed below, and we’ll look at each
one (see Figure 13.4).
• Sound card (2-channel or multichannel).
• I/O interface or breakout box (2 to 16 channels).
• Controller surface with I/O (Input/Output connectors).
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Practical Recording Techniques
MONITOR
HARD
DRIVE
PCI SLOT, USB PORT,
OR FIREWIRE PORT
COMPUTER
KEYBOARD
ALESIS
FIREPORT
I/O INTERFACE
(BREAKOUT BOX)
SOUND CARD
MOUSE
CONTROLLER WITH I/O
AUDIO INTERFACES (CHOOSE ONE)
Figure 13.4
Four types of audio interface used with a DAW.
• Alesis FirePort. This converts wave files from an Alesis HD24 FSTformatted hard drive to FireWire, and sends the data to your computer. FireWire (IEEE-1394) is a high-speed data link for connecting
digital devices.
Sound Card
The simplest form of interface is a 2-channel sound card, which plugs
into a PCI user slot in your computer’s motherboard. Low-cost sound
cards have unbalanced 1/8-inch (mini) phone jack connectors, which
include a mic input, stereo line input, and stereo line output. Generally,
the sound quality and connectors of low-cost cards are not up to professional standards. Current high-quality sound cards can record with 24bit resolution. Many sound cards have MIDI connectors and an onboard
synthesizer. Some have a FireWire port.
The next step up is a sound card with 1/4-inch TRS (Tip-RingSleeve) connectors (Figure 13.5) or XLR connectors on cables. It offers 2
to 8 balanced inputs. Examples are sound cards by Digital Audio Labs,
Frontier Design, SEK’D, Lynx Studio Technology, Echo Digital Audio,
Midiman, Turtle Beach, and RME Hammerfall. A digital-only sound card
is a low-cost choice if you work only with digital signals. A sound-card
comparison is at www.pcavtech.com/soundcards/compare/index.htm.
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Computer Recording
Figure 13.5
13
A sound card.
Choose either a 2-channel or multichannel card. A 2-channel sound
card is adequate if you are recording one instrument at a time (such as a
vocal, sax, keyboard, guitar, or a mix of several drum mics). You can
overdub more parts using the same stereo input on different tracks. Also,
a 2-channel sound card is sufficient if you are using an Alesis FirePort,
which copies several Alesis HD24 recorder tracks to your hard drive,
bypassing the sound card. In that case, you’d use the sound card just for
monitoring.
You’ll need a multichannel sound card (or a multitrack hard-disk
recorder) if you want to record several instruments at once, such as a
band or individual mics on a drum set. This type of card has several connectors on short cables, one per channel. Each instrument’s signal goes
to a separate channel in the sound card, and each channel’s signal is
recorded on a separate track. You can install two or more sound cards
side-by-side to get more channels.
Check the sound card’s Web site to make sure that it is compatible
with your computer and recording software.
Here are some desirable features to look for when shopping for a
sound card:
• 16-bit, 44.1-kHz minimum, full duplex recording. A full duplex card
can record and play back simultaneously. The card works on two
DMA channels.
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Practical Recording Techniques
• 85-dB or greater signal-to-noise ratio, 20 Hz to 20 kHz frequency
response (+/-0.5 dB or less).
• XLR connectors, 1/4-inch TRS phone jacks, RCA phono jacks, MIDI
connectors.
• Operates at +4 dBu as well as -10 dBV.
If the sound card includes an onboard synthesizer chip, look for
these features:
•
•
•
•
•
•
General MIDI (GM) compatible.
MPU-401 MIDI interface compatible.
Wavetable synthesis (better sound than FM synthesis)
Programmable synth patches.
24-note polyphony minimum.
2 MB of wavetable ROM or RAM minimum.
I/O Breakout Box
A more convenient setup than a sound card, but more expensive, is
an outboard audio interface (I/O breakout box) in which all the connectors are in a common chassis. See Figure 13.6. Because the interface’s
analog circuits are outside of the computer, they tend to pick up less computer electrical noise than analog sound cards do. This interface accepts
analog audio or MIDI signals, converts them computer data, and sends
the data to the computer via a PCI, USB, or FireWire connection
(explained later under the heading “Data Transfer Format”).
All breakout boxes accept line-level signals from a mic preamp or
mixer. Some have mic preamps built in. A few have a high-impedance
(hi-Z) 1/4-inch input jack for an electric guitar.
Figure 13.6 A small outboard audio interface, which is a stereo mic preamp
and A/D converter.
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I/O breakout boxes are made by Aardvark, Digidesign, M-Audio,
Echo, Metric Halo, PreSonus, Creative Labs, Tascam, and MOTU (Figure
13.7), among others. Typical prices are $200 to $2495.
When deciding which interface to purchase, some features to look
for are listed below.
Data Transfer Format
The interface has a connector to send digital audio to the computer. This
data can be transferred by PCI, USB, or FireWire formats. PCI is a
common format of slots on a computer motherboard, used for sound
cards. USB and FireWire are protocols for transferring digital data quickly
from one device to another. For example, they transfer digital audio from
an audio interface to your computer.
Outboard interfaces with the USB format are convenient: they plug
into a USB port on the outside of your computer, so you don’t need to
open up the computer to install the interface. Figure 13.8 shows a USB
port and icon.
FireWire comes in two speeds: FireWire 400 (IEEE 1394) which runs
at 400 Mbps (megabits per second), and FireWire 800 (IEEE 1394b) which
runs at 800 Mbps (100 MB per second). In contrast, USB 2.0 high-speed is
480 Mbps.
Figure 13.7
A 16-channel outboard audio interface or I/O breakout box.
Figure 13.8
USB port and cable connector.
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Practical Recording Techniques
You can add a FireWire port to your computer with a $35 FireWire
card, and some computers have FireWire built in. Figure 13.9 shows a
FireWire port and icon.
USB and FireWire devices are hot-swappable: you can insert or
remove the connector while the computer is on. Both formats are compatible with Mac or PC.
Both ports are also available in PCMCIA cards and CardBus cards,
which fit into laptops. A PCMCIA card is a credit-card-size memory card
or I/O device that connects to a slot in a computer. CardBus is an
advanced PCMCIA card with faster speed due to its direct memory access
(DMA) and 32-bit data transfer.
Digital I/O
Some interfaces have digital inputs and outputs as well as analog. If you
have a digital mixer or an outboard A/D converter, a digital-only card
may be all you need. Four digital formats are available:
1. S/PDIF—a coaxial cable with RCA plugs, or an optical connection.
Used with DAT recorders and digital mixers.
2. AES/EBU—an XLR connection used with DAT recorders and digital
mixers.
3. ADAT Lightpipe—an optical connection to Alesis ADAT recorders.
Transfers eight channels of audio at once.
4. Tascam TDIF—a D-sub connection to Tascam multitrack recorders.
Transfers eight channels of audio at once.
Analog I/O
Check whether the analog I/O on the interface is balanced or unbalanced.
Balanced connections reduce electrical interference picked up by cables.
However, unbalanced connections cost less, and usually are adequate for
Figure 13.9
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FireWire port and cable connector.
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13
cable runs under 10 feet. Balanced connectors are XLR or 1/4-inch TRS
phone jacks. Unbalanced connectors are RCA phono jacks or 1/4-inch TS
(Tip-Sleeve) phone jacks.
Sampling Rate and Bit Depth
Available sampling rates in audio interfaces are 32 to 192 kHz. Recordings made with higher sampling rates give better sound quality but
consume more hard-drive space. If you are making CDs, a sampling rate
of 44.1 kHz does the job.
Some interfaces can handle 24-bit as well as 16-bit signals. Recordings made with 24-bit resolution sound a little smoother and cleaner (less
distorted) than 16-bit recordings. Even if your final product is a 16-bit
CD, it will sound better with a 24-bit recording that is dithered down to
16 bits during mastering. Dithering is explained in Chapter 9.
MIDI Ports
Many interfaces have MIDI ports, which accept MIDI signals from a MIDI
controller and send them to your computer’s sequencing software. If
your audio interface has MIDI ports, you don’t need a separate MIDI card
in your computer.
Word Clock
Some interfaces offer word clock connectors, which send and receive
timing signals for digital audio. It’s best to use a single word clock to
drive all the digital devices in your studio with a common clock signal;
this reduces jitter (see details in Chapter 9).
Driver Support
An audio driver is a program that allows recording software to transfer
audio to and from an audio interface. Most interfaces are sold with
several types of drivers. Be sure that your interface has the drivers that
your recording software requires.
A good driver has a minimum latency spec under about 5 msec.
Latency is the signal delay through the driver and interface to the monitor
output. This can be a problem in overdubbing, in which the monitored
signal of the sound source you’re overdubbing is heard later than the prerecorded tracks.
The most popular audio driver formats are ASIO, DAE, Direct I/O,
GSIF, MAS, SoundManager, Wave, WDM, and MME. Here’s a brief
description of each driver format:
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Practical Recording Techniques
• ASIO (Audio Streaming Input and Output) (Mac, PC): A very
popular driver developed by Steinberg. Allows multiple channels
of simultaneous input and output, and low latency with software
synthesizers.
• DAE (Mac, PC): Used only with Digidesign audio interfaces. It’s a
multichannel driver that runs with a compatible host such as Pro
Tools, Logic, and Digital Performer. DAE lets you use RTAS and/or
TDM plug-ins (explained later under the heading “Digidesign Pro
Tools”).
• Direct I/O (Mac, PC): Works with Digidesign interfaces as a
multichannel driver only. Does not let you run RTAS or TDM
effects.
• GSIF (PC): Permits very low latency when playing samples from
hard disk with Tascam’s GigaStudio software sampler.
• MAS (Mac): Developed by Mark of the Unicorn. Offers resolutions
up to 24/96 and multiple simultaneous input and output channels.
It’s also a format for plug-ins (software audio effects).
• SoundManager (Mac): Macintosh’s standard audio driver. It lets you
record and play mono and stereo files up to 16-bit and 44.1 kHz. Has
a moderate amount of latency.
• Wave (PC): The PC standard audio driver. Wave can be used with a
variety of audio interfaces (like Sound Blaster-type sound cards) to
record and play mono or stereo audio. Has a moderate amount of
latency.
• WDM (PC): Win32 Driver Model, a multichannel driver. Allows low
latency with WDM-compatible audio hardware and DXi software
instruments. DXi stands for DirectX Instruments, Cakewalk’s virtual
instrument integration standard. DirectX audio effects can be used
live on input signals, not just during play-back. This lets you
monitor and record effects in real time as you’re recording.
• MME is an older driver that offers lower performance than newer
ones.
CAUTION: If you have multiple drivers installed, they
may conflict. Then the computer might crash or the recording
software might not access the audio interface. Delete unused
drivers.
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Other Options
Listed below are several features that some interfaces offer.
• Zero-latency monitoring: The input signal to the interface is copied
to its output, so you hear the input signal without any signalprocessing delay (latency).
• Pro Tools compatible: The interface works with Pro Tools recording
software and hardware.
• Surround sound: Provides 5.1 or 7.1 surround sound monitoring.
• Powered by FireWire bus or USB bus: The FireWire or USB
connection powers the interface; you don’t need another power
supply.
• Battery powering: This makes the interface portable for on-location
recording with a laptop.
• Supplied recording software: The interface is packaged with recording software, so you might not need to buy other software.
• A/D/A converter mode: The interface can act as a real-time analogto-digital (A/D) and digital-to-analog (D/A) converter.
• SMPTE sync: The interface will synchronize with a SMPTE time
code signal (see details in Appendix C).
Control Surface
So far we’ve covered the computer and audio interface. Let’s look at other
hardware for a computer studio.
Using a mouse to adjust the controls on-screen is slow and can lead
to repetitive stress syndrome. An alternative is a DAW control surface or
controller (Figure 13.10). It’s a chassis with physical controls for software
functions. Resembling a mixer with real faders, knobs, and transport
buttons, it lets you adjust the software’s virtual controls that you see on
the monitor screen. The controller attaches to the computer through a
MIDI connector, Ethernet connector, USB, or FireWire port.
Many control surfaces also act as audio interfaces: they include
mic/line inputs and outputs (I/O) and MIDI connectors.
Some control surfaces are dedicated to one DAW recording program,
such as Pro Tools. Others are universal: they work with several different
DAW programs. Be sure to check whether the controller you want to buy
will work with your recording software.
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Practical Recording Techniques
Figure 13.10
A control surface.
What if your controller has 8 faders, but your project has 16 virtual
faders on screen? You can make the controller affect groups (banks) of
virtual faders, 8 at a time, by pressing a bank switch. Normally, your controller faders will affect virtual faders 1 through 8. Press the bank switch
to make the controller faders affect virtual faders 9 through 16. Press it
again to access virtual faders 17 through 24, and so on. Controllers that
have 4 faders can access banks of virtual faders 4 at a time.
Advanced controllers offer these features:
• Motorized faders: The faders in the control surface are motorized,
so they move like the virtual faders on screen.
• Standalone mixer mode: You can use the control surface as a regular
mixer.
• Footswitch jack: Accepts a footswitch for punch-in/out. The
footswitch works only if your recording software supports this
function.
• Meters.
• Monitoring section.
• Aux send/return: Allows you to connect an external analog signal
processor.
• Insert jacks: An insert jack in series with each channel’s signal allows
you to plug in an analog compressor.
• Expandability: You can add more controllers, side-by-side, to control
more virtual faders at once.
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Note that a MIDI controller or a MIDI fader box can control a
sequencer’s MIDI tracks, but not audio virtual controls. A control surface
can control both.
The Frontier Design TranzPort is a wireless remote control for a
DAW, letting you control your DAW from the studio. It includes transport controls, metering, a footswitch jack, and more. See the Web site
www.frontierdesign.com for more information.
Alesis FirePort
This is a special type of audio interface that transfers audio tracks from
an Alesis HD24 multitrack recorder to a computer. The HD24 records
tracks as wave files on an Alesis FST-formatted hard drive that is plugged
into the recorder. After recording tracks, you can remove the hard drive
and plug it into an Alesis FirePort (Figure 13.4), a small device that converts those tracks’ wave files to FireWire format and sends them to your
computer hard drive for editing and mixing.
As we’ve seen, there are a wide range of features and connectors
among different interface models. A good interface is well worth the price
because of its top-quality sound, convenient connections, and easy
control of audio signals.
DSP Card
Another DAW option is a digital signal processing (DSP) card that you
plug into a user slot in your computer’s motherboard. Why is it helpful?
The more software effects (plug-ins) you use, the fewer tracks you can
mix, because effects put a big load on the CPU. Normally this is not a
problem except in mixes with more than 24 tracks and loads of plug-ins
in use. You can resolve this issue by installing a DSP card, which handles
the processing for the plug-ins. The plug-ins access the card rather than
the CPU. You can install multiple cards to expand the system. Examples
are TC Works Powercore, Digidesign TDM-based Pro Tools cards, Mackie
UAD-1 PCI card, and CreamWare Pulsar PCI cards.
Analog Summing Amplifier
This device is a mixer without faders, used to mix tracks or submixes
from a DAW through analog circuitry. Two examples are the Dangerous
2BUS 16 ¥ 2 mixer and the Manley Labs 16 ¥ 2. By using a summing
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Practical Recording Techniques
amplifier, you bypass the DAW’s internal mix bus which might create
slight distortion due to rounding errors, numeric overload, and bit truncation. (Some DAW software claims not to produce those errors, such as
Pro Tools TDM systems.) You connect each DAW track’s analog output
to a summing amplifier input, and use the DAW’s faders and automation to set mix levels. Some engineers claim to avoid the distortion of
mixing inside the computer by mixing at lower levels.
Recording Software
Now let’s turn from hardware to software. Some popular programs for
recording, editing, and mixing are Adobe Audition, MOTU Digital
Performer (Mac only), Steinberg Cubase SX and Nuendo, Digidesign Pro
Tools, Apple GarageBand, Cakewalk Music Creator, Home Studio and
Sonar; Emagic Logic (for Mac only), Sony Pictures Digital Vegas and
Sound Forge, BIAS Deck, Pro Tracks Plus, Magix Samplitude, Mackie
Tracktion, Magix Sequoia, and RML Labs SAW Studio. They share a lot
of the same features but implement them differently. Also, each product
has unique features and its own GUI.
Check out the products online to see how you might like working
with them. Some Web sites have interactive demos; others have free trial
versions that you can download.
Free multitrack recording programs are available for download.
Although they lack extensive features, they offer a chance to practice your
skills at no cost. Examples are Pro Tools Free, N Track Studio, and Kristal
(from Kreative.org).
When you first install recording software or hardware, expect some
frustration. Your software may not be compatible with your hardware, or
may not perform as expected. You might need to modify certain settings
in your computer system or recording software. Read the manual and
any readme files that came with your product. Also, check out the products’ Web sites for knowledge bases, FAQs, etc. Each DAW program has
online discussion groups. If you’re still having problems, call or e-mail
the tech support for your product.
For each recording program, books are available that provide operating details and power-user tips. To find them, search www.amazon.com
or the references in Appendix D. Type the name of the program and manufacturer in the search field.
This chapter is not meant to duplicate the information in those specialized books. Instead, it provides an overview of recording software.
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Features
Here are some features you’ll find in most recording programs:
• Multitrack digital recording from 2 tracks on up: Some programs can
record and play back an unlimited number of tracks depending on
the speed of your computer, RAM, and hard drive.
• MIDI sequencer: This lets you import or record several tracks of
MIDI performance data, edit it, and play it. MIDI sequencer tracks
can be mixed with audio tracks.
• Customizable GUI: Change the graphical user interface to suit the
way you work. Create configurations to use as templates for similar
projects.
• Keyboard shortcuts: Instead of constantly using a mouse, tap certain
keys on your computer keyboard. This speeds operation and gives
your mouse hand a rest.
• Virtual tracks: Extra takes of a musical performance that are
recorded on the hard drive. During mixdown you can choose the
best takes to use, or the best parts of each take. Some DAWs have
256 virtual tracks, but 16 real tracks. In that case you can mix 16
tracks during mixdown, but some of those 16 tracks might have
several virtual tracks or alternate takes that can be accessed during
mixdown.
• Automated mixing: All settings for a song project can be saved and
automated. The computer remembers your mix moves, and sets the
mixer faders and pan pots accordingly during subsequent mixdowns. Some programs let you automate effects settings as well.
For more information, see the section on Automated Mixing in
Chapter 12.
• Locate and marker points: Mark several points in a song (intro,
verse, chorus, solos) so that you can go to them instantly.
• Routing or virtual patchbay: Assign any input to any track.
• Video display: An on-screen window that shows video clips. Found
in high-end software, this feature lets you synchronize music and
sound effects to a video program.
• CD recording: Record your mixes on a CD burner.
• PQ editing: Set up a list of song start times before burning a CD of
your mixes.
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Practical Recording Techniques
• Spectral analysis: A display of level versus frequency of the audio
program as it progresses in time.
• Notation application: Converts a MIDI file to musical notes on a
treble and bass clef.
• Sync: Synchronization to SMPTE time code or MIDI time code (see
details in Appendix C).
• Plug-ins: Described below.
Plug-Ins
A plug-in is a software module that adds digital signal processing or
effects to a DAW recording program. For example, you can insert a
reverb, compressor, or equalizer plug-in into an audio track.
To create effects, each plug-in runs an algorithm (short program) in
your computer’s CPU, or in DSP cards that plug into your computer.
Because plug-ins work inside the computer, no external processors or
patch cords are needed. Any effect available in hardware is also available
as a software plug-in. Unlike hardware effects, plug-ins are instantly
upgradeable—just download the latest version.
Recording software comes with several plug-ins already installed.
You also can purchase and download plug-ins from the Web. When you
install the plug-in software, it becomes part of the DAW program, and
you can call it up when you need it. Your DAW becomes the “host,” and
the plug-in provides extra effects that did not come with the host
program.
When you click on the name of a plug-in, a screen pops up that looks
like a hardware processor with knobs, faders, lights, and meters. Parameters (such as reverb time, chorus depth, or compression ratio) can be
adjusted, and most parameters can be saved and automated.
A number of plug-ins can simulate or model the sound of specific
devices. For example, Amp Farm by Line 6 is a guitar-amp modeling
plug-in, while Antares Microphone Modeler can simulate the sound of
popular studio mics. Vintage compressors, tube mic preamps, concert
halls, and analog tape recorders have been modeled as well.
Some plug-ins run in real time as the audio is playing. Others
process a sound file and create a new file as with normalization or time
compression/expansion.
Plug-in effects can be applied in three ways:
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1. Master effect: The effect is on the master output bus, and processes
the entire mix. Multiband compression is a typical master effect.
2. Aux or send effect: The effect is on an aux bus. Set the plug-in’s
dry/wet mix control all the way to “wet” or “100% mix.” Adjust the
amount of effect on each track by turning up the track’s aux send
control. This option reduces the number of plug-ins needed for a
mix, and so reduces the load on your CPU. Delay effects—reverb,
echo, chorus and flanging—are aux effects.
3. Insert effect: This effect is on a specific track and affects only that
track. EQ and compression are insert effects. If you insert a delay
effect into a track, you adjust the dry/wet mix control in the effect
to control the amount of effect that you hear.
Plug-ins come in several formats; the most popular for Windows are
Steinberg’s Virtual Studio Technology (VST) and DirectX. DirectX is a
group of application-program interfaces that enhance multimedia (video
and audio) on Windows systems. Some plug-in manufacturers make
plug-in bundles, which are a variety of effects in a single package. An
example is the WAVE audio bundle.
You can find plug-ins on vendors’ Web sites or on the Web sites of
recording-software companies. For example, Digidesign’s Web site lists
dozens of plug-in partners.
Examples of DAW Software
We’ve looked at DAW software in general. Now let’s examine a few
representative applications: Adobe Audition, Cakewalk Sonar, and
Digidesign Pro Tools.
Adobe Audition
This low-cost but powerful program uses the computer’s CPU for digital
signal processing (Figures 13.11 and 13.12). It does not support MIDI
sequencing or VSTi/DXi virtual instruments. Instead, it focuses on audio
work. Listed below are some of its unique features.
• Up to 128 stereo tracks.
• Up to 32-bit resolution, up to 10 MHz sampling rate, including standard rates.
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Practical Recording Techniques
Figure 13.11
Adobe Audition multitrack view.
• All edits are sample-accurate. They can be automatically snapped to
zero crossings (points where the waveform crosses the zero-volts
line), which results in click-free edits. Short crossfades can be added
for smooth, pop-free cuts.
• More than 45 DSP tools and effects, mastering and analysis tools,
and audio restoration features are included. Third-party DirectX and
VST effects plug-ins are supported.
• Precise sample rate conversions from 44.1 to 48 kHz for video or 96
kHz for DVD.
• Track-volume envelopes (fader-setting graphs) can be adjusted to
produce gradual, nonlinear changes, and can be scaled.
• Correct pitch. Remove vocals from a stereo program, or reduce the
vocal level. Change a clip’s length without changing its pitch. Select
and edit sounds in frequency or time views.
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Computer Recording
Figure 13.12
13
Adobe Audition edit view.
• Import audio from Adobe Premiere Pro or After Effects software for
use in Adobe Audition. Use the Edit Original command to make
changes to the original wave file and import the changes into Adobe
Audition.
• Organizer window lets you access currently open audio, MIDI, and
video files; effects; and favorites. Create keyboard shortcuts.
• Multichannel encoder transforms a multitrack mix into 5.1 surround
sound.
• Audio for video. Open video files in the multitrack view (AV, native
DV, MPEG, WMV) and edit the soundtrack in Adobe Audition.
Create new soundtracks, sweeten existing recordings, reduce noise,
etc.
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• Looping tools let you create music for songs or movie soundtracks.
Loops (repetitive drum or music patterns) automatically match the
recording’s tempo and key. Loop-based recording is covered in
Chapter 16 on MIDI.
• Includes 5000 original, performance-based loops in a wide range of
musical genres. Supports more than 20 file formats and variations,
including Windows PCM (WAV), AIFF, MP3, and WMA 9. Twenty
sample sessions included.
• Digitally extract audio CDs to your hard drive for use in projects.
Integrated CD burning.
• Transfer audio quickly to other Rewire-supporting applications.
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about
Adobe
Audition
is
at
http://www.adobe.com/products/audition/main.html. From there,
you can download a trial version, check system requirements, see a video,
read a tutorial, and read an overview or in-depth information. Details
about Adobe Audition are at http://www.adobe.com/products/
audition/pdfs/audition_nph.pdf
Cakewalk Sonar
Like Adobe Audition, Cakewalk software is cost-effective but powerful,
and uses the computer’s CPU for all processing. Products range from
Home Studio ($125 street) to Sonar Producer ($600 street) (Figure 13.13).
Below are some unique features of Sonar Producer:
• Graphical envelope automation control of audio, MIDI, synths, and
effects.
• Professional metering (peak, rms, peak and rms, adjustable ballistics, pre-fader, post-fader, and pre-fader post effects).
• Loop-based composition, construction, and editing tools.
• ACID-loop and MIDI Groove Clip support.
• Support for DirectX and VST audio effects. (DirectX is a standard
audio driver.)
• 29 included audio effects.
• Support for DXi and VSTi soft synths. (VSTi stands for Virtual Studio
Technology for Instruments, Steinberg’s virtual instrument integration standard.)
• Several included DXi soft synths and samplers.
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Computer Recording
Figure 13.13
13
Sonar screen view.
• Support for ReWire 1.0 and 2.0 clients (Project5, Reason, etc.).
• 13 included MFX (MIDI effects) plug-ins. Support for real-time, nondestructive MIDI FX plug-ins. Full plug-in delay compensation.
• Works with many MIDI-compatible control surfaces.
• Surround mixing (5.1 and 7.1)
• Custom screen layouts and colorization. User-definable keyboard
shortcuts and templates for other DAWs.
• Multitrack Piano Roll and Drum Editor. Custom, multi-port drum
mapping.
• Full notation of MIDI with lyrics, chord symbols, guitar tablature,
etc.
• Event List view with display filtering, Tempo view with list and
graph displays, Markers view.
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Practical Recording Techniques
• Track Folders let you file multiple tracks into a single folder and edit
them simultaneously.
• Track Layers displays multiple takes on one track for easy comping.
• Freeze function mixes down effects and edits on a track to free up
CPU resources. Unfreeze returns to the original setup.
• Advanced project and file management tools.
• OMFI and Broadcast Wave import/export for cross-platform collaboration with Digital Performer, Logic, Nuendo, and Pro Tools
studios.
• Import formats: AIF, ASF, AU, AVI (with stereo or 5.1 audio), Broadcast Wave, MIDI, MP2, MP3, MPEG, MPG, OMFI, QuickTime, SND,
WAV, Windows Media Audio 9 (WMA), WMA9 Pro 5.1, WMA9 lossless, Windows Media Video, and proprietary Cakewalk formats
(.bun, .cwb, .cwp, .wrk).
• Export: WAV, ACID-format WAV, Broadcast Wave, AVI (with stereo
or 5.1 audio), OMFI, MIDI, MP3 (30-day trial encoder), QuickTime,
Real Audio G2, Windows Media Audio 9 (WMA), WMA9 Pro 5.1,
WMA9 lossless, Windows Media Video (with stereo or 5.1 audio),
and proprietary Cakewalk formats (.cwb, .cwp); Other audio
formats supported via external command-line encoders.
• Open support for external encoders: surround, LAME, Ogg Vorbis,
Monkey’s Audio, etc.
• 32-bit floating-point resolution of the DSP.
• Audio bit depths up to 24 bit, any sample rate.
• Reliable synchronization of audio, MIDI, video, external hardware.
• Sample-accurate timing for audio, soft synths and automation; 960
PPQN for external MIDI devices. Frame-accurate SMPTE sync with
auto-detection of timecode.
• Yamaha OPT Level 1 MIDI Hardware Link support.
• Multiple video monitor support. Multi-processor support.
• ASIO and WDM compatibility.
• Surround panning and effects.
Sonar Studio Edition is a special version of Sonar designed for
project studios and aspiring professionals. Sonar Studio and Sonar Producer are the same, except that Sonar Producer has these extra features:
an enhanced virtual mixing console (with per channel EQ, assignable
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Computer Recording
13
effects controls), VSampler 3.0 DXi, Ultrafunk Sonitus Effects Suite, a
professional sample library, and Lexicon Pantheon Reverb (the Studio
version has Lexicon LE), surround mixing and editing, Sonitus Surround
Compressor, video thumbnail track, POW-r Dithering, and MPEX time
scaling.
Digidesign Pro Tools
Pro Tools is the industry standard DAW system. However, other excellent programs are available. People often use the term “Pro Tools” generically to mean “digital audio workstation.”
There are two basic categories: Pro Tools LE and Pro Tools HD.
Pro Tools LE is a 32-track recording system that uses your computer’s CPU for all processing. Your CPU speed, hard-drive speed, and
amount of RAM determine how many plug-ins and soft synths you can
use simultaneously.
LE systems are intended for singer/songwriters, project and
personal studios, remote recording engineers, and bands. Pros can use
it at home because it is compatible with Pro Tools HD. Cost is $500 to
$3000.
Pro Tools HD is a high-resolution professional system with DSP
cards, up to 192-kHz sample rate, expandable I/O, and many options. It
comes in three Core systems (each with more DSP power and more I/O)
and one or more audio interfaces. Each system requires the Pro Tools 192
I/O or the 96 I/O audio interface, and supports legacy Pro Tools audio
interfaces for additional inputs and outputs. Cost is $10,000 to $100,000
or more.
Pro Tools LE components include Pro Tools LE software and a choice
of Mbox, Digi 002 Rack, or Digi 002 Rack interfaces.
• Mbox is a USB audio interface with two Focusrite mic preamps. It
includes Digitial S/PDIF I/O, line and insert I/O and 2-channel
stereo outputs.
• Digi 002 is a control surface and audio interface. It communicates
with your computer via FireWire. It includes 8 analog ins and outs,
4 mic preamps, 8 channels of ADAT I/O, stereo S/PDIF and MIDI
I/O, 8 touch-sensitive faders, and 8 motion-sensitive rotary
encoders. It includes transport buttons and automation. Any
changes you make in your Pro Tools software are duplicated on the
control surface and vice versa.
• Digi 002 Rack is Digi 002 in a 2U rack-mount chassis.
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Practical Recording Techniques
Pro Tools HD Systems offer dedicated DSP cards that free up your
CPU for other tasks. The result is you can run more tracks, more plugins, and more soft synths at the same time. HD offers a wide range of
sample rates, hi-res audio, and up to 192 tracks. An HD system can have
8 to 96 ins and outs. The three basic Core systems have one, two, or three
DSP cards, and a system can use up to seven DSP cards.
Listed below are the three Core systems. Each can be expanded by
adding more HD Accel cards.
• Pro Tools HD 1 includes the HD Core DSP card, which handles up
to 32 channels of I/O and up to 96 tracks.
• Pro Tools HD 2 Accel includes the HD Core card and an HD Accel
card, which provide more than four times the mixing and processing power of HD 1 systems and 64 channels of I/O and 192 tracks.
• Pro Tools HD 3 Accel, the most powerful system, includes the HD
Core card and two HD Accel cards, which provide up to 96 channels of I/O and 192 tracks.
The Digidesign 96 I/O Audio Interface converts audio at up to 24bit/96 kHz. It includes 8 channels of analog I/O, 8 channels of ADAT
optical I/O, 2 channels of AES/EBU and S/PDIF I/O, and word clock. It
can link to other 96 I/O interfaces and to Digidesign 888/24, 882/20,
1622, or 24-bit ADAT Bridge.
The Digidesign 192 I/O Audio Interface converts audio at up to
24-bit/192 kHz. It includes 8 channels of analog I/O, 8 channels of
AES/EBU, 8 channels of TDIF, 16 channels of ADAT, and 2 additional
channels of ADAT or S/PDIF digital I/O. A 192 Digital expansion card
provides 8 more channels of AES/EBU, TDIF, and ADAT I/O connections and a Legacy port to link to older Digidesign interfaces.
New features of the latest Pro Tools software are on the
www.protools.com Web site.
Pro Tools FREE is free software that records up to 8 tracks and uses
the computer’s CPU for processing (Figure 13.14).
Plug-ins for Pro Tools come in four formats: TDM, HTDM, RTAS
(Real Time Audio Suite), and AudioSuite. TDM plug-ins work only with
Pro Tools’ professional TDM systems, and use dedicated cards that plug
into your computer. HTDM is the same for the Pro Tools HD (high definition) system. Many RTAS plug-ins are the same as TDM plug-ins,
except that they use your computer’s processor instead of specialized
TDM DSP cards. All the above plug-ins work in real time.
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Computer Recording
Figure 13.14
13
Pro Tools 6.4 screen view.
AudioSuite plug-ins don’t work in real time. Instead, they process a
track’s signal and create a new track in which the effect is part of the
recorded sound. That is, the effects are embedded in the track. Playing a
track with embedded effects is less work for the CPU than playing a track
with real-time effects. Less load on the CPU means you can play more
tracks without drop-outs.
Loads of plug-ins are available for Pro Tools. Some are included, and
some can be downloaded from third-party vendors. Use the plug-in
finder on the Pro Tools Web site (www.protools.com).
Listed below are some unique features of Pro Tools LE:
• Up to 32 audio tracks at 24-bits/96 kHz.
• Accepts music created in ReWire-compatible audio applications
such as Propellerhead’s Reason soft synth and Ableton Live looping
application. (ReWire is Propellerhead/Steinberg’s technology for
transferring audio data between software applications.)
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Practical Recording Techniques
• Version 6.1 or later works with Windows XP or Mac OS X.
• MIDI Time Stamping, Groove Quantize, Restore Performance, and
other enhancements.
• In 6.1 and later versions, Time Trimmer can change the tempo of
audio files and loops.
• All data is compatible with other Pro Tools systems, and can be
moved back and forth between them.
• Has nearly the same user interface as professional Pro Tools TDM
systems.
Included with every Pro Tools system is a Music Production
Enhancement Suite, which includes Reason soft synth, Live looping,
AmpliTube guitar-amp, and stomp-box modeling, SampleTank sampleplayback module, and T-Rack’s tube-based parametric EQ.
ProControl and Control|24 are powerful control surface options for
Pro Tools. Listed below are the features of each:
ProControl Control Surface with I/O:
• High-quality faders and switches. Expandable to 48 faders.
• DSP Edit/Assign section.
• 8-character LED scribble strips (displays that identify what instrument each fader affects).
• Edit Pack option features two touch-sensitive motorized surround
joystick panners, 8 high-resolution output meters to view up to 7.1
surround mixes, MachineControl, custom keyboard, and trackball.
• 16 Focusrite mic preamps.
Control|24 Control Surface has these features:
•
•
•
•
Fixed at 24 faders.
4-character scribble strips that show channel or plug-in information.
6 regular resolution output meters.
No audio inputs or outputs.
Optimizing Your Computer for Digital Audio
Once you’ve chosen some recording software and installed it, you’ll want
to make your computer run as fast and glitch-free as possible. You need
to optimize its settings for best results. Appendix B suggests some ways
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Computer Recording
13
to speed up your hard drive, reduce software interruptions, and reduce
the CPU usage. If you follow those tips, you will have a faster system
that handles more plug-ins and more tracks at once. Also, when you play
tracks or burn CDs, clicks and drop-outs in the audio will be less likely.
Using a DAW
Let’s say you purchased some DAW hardware and software, and
tweaked your computer to make it fast and reliable. It’s ready to rock.
Here are some tips on setting up and using your DAW.
Connections
First, connect your audio equipment to the DAW as described below.
1. If you want to use a mixer or a standalone multitrack recorder in
your studio, make the connections shown in Figure 13.15. If your
mixer is analog, connect it to the audio-interface analog connectors.
If your mixer is digital, connect it to the audio-interface digital
connectors.
2. If you are not using a mixer, make the connections shown in Figure
13.16.
3. You may need some adapter cables between devices. The following
adapter cable connects a sound card’s unbalanced I/O to a power
POWER AMPLIFIER
AND MONITOR SPEAKERS,
OR POWERED MONITORS
MICS / DI
MICS
IN
SNAKE
MONITOR
OUT
L
R
MIXER
HEADPHONES
L
R
INSERT
SEND/RETURNS
IN / OUT
TAPE/LINE
LINE
OUT
IN
LINE
OUT
TAPE/LINE
IN
COMPUTER
WITH AUDIO
INTERFACE
MULTITRACK
RECORDER
(OPTIONAL)
Figure 13.15
Connecting audio equipment to a DAW if a mixer is used.
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Practical Recording Techniques
POWER AMPLIFIER
AND MONITOR SPEAKERS,
OR POWERED MONITORS
COMPUTER
LINE OUT
MIC
IN
MIC OR DI
OR
MIC OR DI
LINE
IN
AUDIO
INTERFACE
SOUND CARD,
I/O BREAKOUT BOX
OR CONTROLLER
MIC
PREAMP
USB,
FIREWIRE
OR
PCI SLOT
HEADPHONES
Figure 13.16
Connecting audio equipment to a DAW if a mixer is not used.
amp, powered speakers, or mixer: Stereo 1/8-inch phone plug, to
two unbalanced phone plugs, or two RCA phono plugs (whatever
matches your equipment).
Starting from your computer’s desktop view, select Start > Settings
> Control Panel. Double-click Sound and Audio Devices > Audio tab. Set
the Playback and the Recording default devices to the soundcard or interface you are using for audio editing.
Before you record, set a bit depth and sampling rate for the project,
such as 24-bit/44.1 kHz. If you want to record from a mic or instrument,
you will record their amplified signal on an audio track. If you want to
record from a MIDI controller, you will record its MIDI signal on a MIDI
track. Details on recording MIDI sequences are in Chapter 16.
Specify the input and output devices for each audio track, such as
“sound-card left channel input” and “sound-card stereo outputs.” Also,
specify the input and output devices for each MIDI track, such as “MIDIcard omni input” and “sound-card stereo outputs.”
Maintaining Quality
Here are some tips on keeping the audio quality high when using a DAW.
Set gain staging as follows: Open the application that shows the
volume controls for your sound card or audio interface. Use the record
volume control (if any) to set the recording level. When your mic preamp
or mixer is peaking at 0 dB, set the software record volume control so the
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Computer Recording
13
on-screen level meter peaks at 0 dB or slightly less. If your mic preamp
or mixer has a VU meter, play a 1-kHz tone through the mixer at 0 VU,
and set the software record level to -15 dBFS (decibels Full Scale). This
allows headroom for transient peaks that are too fast to show up on the
VU meter.
When you set recording levels, each track’s meter should peak
around -5 dBFS maximum (with the meter set to peak meter mode). This
allows some headroom for surprises. Also, musicians generally play
louder during a performance than during a level check. If you exceed
0 dBFS you’ll hear digital clipping distortion.
If you are recording many tracks simultaneously, or at a high sample
rate, this may generate more data than your CPU and buffers can
handle—causing drop-outs. A drop-out is a short silence or a noise burst
(glitch) in the recorded audio. To prevent drop-outs while recording, turn
off the time counter, track metering, effects, and waveform preview.
Increase buffer size. Turn off or reduce video acceleration. Do not zoom
or scroll while recording. Record one song at a time in a concert recording. Also, follow the tips in Appendix B on optimizing your computer for
digital audio.
In your recording program, go to the Preferences menu and set an
appropriate buffer size. Small buffers tend to create drop-outs, or reduce
the number of tracks that play without drop-outs, but the application
responds faster. Large buffers reduce drop-outs but increase latency
(monitoring delay). Latency is buffer size divided by sample rate. You
might set the buffer/latency small (under 5 msec) while overdubbing and
set it large during mixdown.
To avoid latency while overdubbing an instrument or vocal, plug the
instrument or vocal mic into a mixer. Connect the direct output of that
mixer channel to your audio interface input. Connect the interface output
(a mix of the recorded tracks) to another mixer input. Monitor the mixer’s
output. Set up a mix of the live instrument and the interface output.
Consider recording at 44.1 kHz, because that is the digital format for
CDs. Recordings made at 88.2 or 96 kHz consume about twice as much
disk space. 24-bit recordings sound better than 16-bit recordings but
consume 50% more disk space. Recording at 24 bits is considered by
many to be a bigger sonic improvement than recording at 96 kHz.
After recording all the tracks, delete silent sections in each track to
reduce leakage and background noise. To do that, zoom into a single
track, highlight a silent portion, and select Edit > Cut (or a similar
command). Another method is to mute a track up to where the sound
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Practical Recording Techniques
starts, then unmute it there. Or slip-edit the beginning and end of a track
to where the sound starts and ends.
During mixdown, keep the output level of the stereo mix bus around
-3 dBFS maximum (in peak meter mode, not rms). Try to keep the main
output fader at or near 0 dB, and adjust the channel faders to get the
correct output level (without changing their balance). To achieve that, you
might start with all channel faders set to -12 dB, then bring up a few channels that need to be louder. Keep your playback levels high but not clipping on each track and in each plug-in. It’s easy to overload an equalizer
if you apply boost, so reduce the equalizer’s overall level if necessary so
that no clipping occurs in the EQ plug-in.
For best quality, record at 24 bits and stay there throughout the
project. Then turn on dither and export to a 16-bit file that you will master
for a CD. If you are mastering to a 24-bit device, set the output word
length to 24-bit and turn on dither. That will retain some of the 32-bit
resolution of the DAW’s DSP calculations.
Normalization is a DAW process that raises the gain of the entire
program so that the highest peak reaches 0 dBFS (in peak meter mode,
not rms). Do not normalize the program until final mastering.
To prevent hum and jitter, keep audio and digital cables away from
power cords and power amps. Use cables designed for digital audio, and
use short cables. Use internal sync on your A/D converter to reduce jitter.
Avoid A/D and D/A conversions. Once your signal is digital, try to
keep it that way. After converting the analog mic signal to digital in your
audio interface, do all your processing in the computer if possible, then
burn a CD of the final product. The only D/A conversion will be when
the CD plays back.
Avoid unnecessary processing. DSP such as level changes result in
slight distortion. If you raise the level of a section or of an entire song
then change your mind, don’t reduce its level back where it was, because
that is twice the processing. Return to the original recording instead.
As we’ve seen, there is a whole world of computer music applications. Download the free trial versions to see what you like. Set up your
DAW system, read the software manual, and have fun creating music.
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14
JUDGING SOUND QUALITY
Seat an engineer behind a mixing console and ask him or her to do a mix.
It sounds great. Then seat another engineer behind the same console and
again ask for a mix. It sounds terrible. What happened?
The difference lies mainly in their ears—their critical listening
ability. Some engineers have a clear idea of what they want to hear
and how to get it. Others haven’t acquired the essential ability to recognize good sound. By knowing what to listen for, you can improve your
artistic judgments during recording and mixdown. You are able to hear
errors in microphone placement, equalization, and so on, and correct
them.
To train your hearing, try to analyze recorded sound into its components—such as frequency response, noise, reverberation—and concentrate on each one in turn. It’s easier to hear sonic flaws if you focus
on a single aspect of sound reproduction at a time. This chapter is a guide
to help you do this.
Classical versus Popular Recording
Classical and popular music have different standards of “good sound.”
One goal in recording classical music (and often folk music or jazz) is to
accurately reproduce the live performance. This is a worthy aim because
the sound of an orchestra in a good hall can be quite beautiful. The music
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Practical Recording Techniques
was composed and the instruments were designed to sound best when
heard live in a concert hall. The recording engineer, out of respect for the
music, should always try to translate that sound to disk with as little technical intrusion as possible.
By contrast, the accurate translation of sound to disc is not
always the goal in recording popular music. Although the aim may be
to reproduce the original sound, the producer or engineer may also want
to play with that sound to create a new sonic experience, or to do some
of both.
In fact, the artistic manipulation of sounds through studio techniques has become an end in itself. Creating an interesting new sound is
as valid a goal as re-creating the original sound. There are two games to
play, each with its own measures of success.
If the aim of a recording is realism or accurate reproduction, the
recording is successful when it matches the live performance heard in the
best seat in the concert hall. The sound of musical instruments is the standard by which such recordings are judged.
When the goal is to enhance the sound or produce special effects
(as in most pop-music recordings), the desired sonic effect is less
defined. The live sound of a pop group could be a reference, but
pop-music recordings generally sound better than live performances—
recorded vocals are clearer and less harsh, the bass is cleaner and
tighter, and so on. The sound of pop music reproduced over speakers
has developed its own standards of quality apart from accurate
reproduction.
Good Sound in a Pop-Music Recording
Currently, a good-sounding pop recording might be described as follows
(there are always exceptions):
•
•
•
•
•
•
•
318
Well-mixed
Wide-range
Tonally balanced
Clean
Clear
Smooth
Spacious
Judging Sound Quality
14
It also has:
•
•
•
•
•
•
•
Presence
Sharp transients
Tight bass and drums
Wide and detailed stereo imaging
Wide but controlled dynamic range
Interesting sounds
Suitable production
The next sections explore each one of these qualities in detail so that
you know what to listen for. Assume that the monitor system is accurate,
so that any colorations heard are in the recording and not in the
monitors.
A Good Mix
In a good mix, the loudness of instruments and vocals is in a pleasing
balance. Everything can be clearly heard, yet nothing is obtrusive. The
most important instruments or voices are loudest; less important parts
are in the background.
A successful mix goes unnoticed. When all the tracks are balanced
correctly, nothing sticks out and nothing is hidden. Of course, there’s a
wide latitude for musical interpretation and personal taste in making a
mix. Dance mixes, for example, can be very severe sonically.
Sometimes you don’t want everything to be clearly heard. On rare
occasions you may want to mix in certain tracks very subtly for a subconscious effect.
The mix must be appropriate for the style of music. For example, a
mix that’s right for loud rock music usually won’t work for a pop ballad.
A rock mix typically has the drums way up front and the vocals only
slightly louder than the accompaniment. In contrast, a pop ballad has
the vocals loudest, with the drums used just as “seasoning” in the
background.
Level changes during the mix should be subtle, or should make
sense. Otherwise, instruments jump out for a solo and fall back in afterwards. Move faders slowly, or set them to preset positions during pauses
in the music. Nothing sounds more amateurish than a solo that starts too
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Practical Recording Techniques
quietly and then comes up as it plays—you can hear the engineer
working the fader.
Wide Range
Wide range means extended low- and high-frequency response. Cymbals
should sound crisp and distinct, but not sizzly or harsh; kick drum and
bass should sound deep, but not overwhelming or muddy. Wide-range
sound results from using high-quality microphones and adequate EQ.
You might want to combine “hi-fi” and “low-fi” sounds in a single
mix. The low-fi sounds generally cover a narrow frequency range and
might be distorted.
Good Tonal Balance
The overall tonal balance of a recording should be neither bassy nor
trebly. That is, the perceived spectrum should not emphasize low or high
frequencies. Low bass, mid-bass, midrange, upper midrange, and highs
should be heard in equal proportions (Figure 14.1). Emphasis of any one
frequency band over the other eventually causes listening fatigue. Dance
club mixes, however, are heavy on the bass end to get the crowd moving.
Recorded tonal balance is inversely related to the frequency
response of the studio’s monitor system. If the monitors have a highfrequency rolloff, the engineer will compensate by boosting highs in the
recording to make the monitors sound correct. The result is a bright
recording.
Figure 14.1
320
Loudness versus frequency of a pop recording with good sound.
Judging Sound Quality
14
Before doing a mix, play over the monitors some commercial recordings whose sound you admire, to become accustomed to a commercial
spectral balance. After your mix is recorded, play it back and alternately
switch between your mix and a commercial recording. This comparison
indicates how well you matched a commercial spectral balance. Of
course, you may not care to duplicate what others are doing. An effective tool for this purpose is Harmonic Balancer (www.har-bal.com).
In pop-music recordings, the tonal balance or timbre of instruments
does not necessarily have to be natural. Still, many listeners want to hear
a realistic timbre from acoustic instruments, such as the guitar, flute, sax,
or piano. The reproduced timbre depends on microphone frequency
response, microphone placement, the musical instruments themselves,
and equalization.
Clean Sound
Clean means free of noise and distortion. Hiss, hum, and distortion are
inaudible in a good recording. Distortion in this case means distortion
added by the recording process, not distortion already present in the
sound of electric-guitar amps or Leslie speakers. There are exceptions to
this guideline; some popular recordings have noise or distortion added
intentionally.
Clean also means “not muddy” or free of low-frequency ringing and
leakage. A clean mix is one that is uncluttered or free of excess instrumentation. This is achieved by arranging the music so that similar parts
don’t overlap, and not too many instruments play at once in the same
frequency range. Usually, the fewer the instruments, the cleaner the
sound. Too many overdubs can muddy the mix.
Clarity
In a clear-sounding recording, instruments do not crowd or mask each
other. They are separate and distinct. As with a clean sound, clarity arises
when instrumentation is sparse, or when instruments occupy different
areas of the frequency spectrum. For example, the bass provides low frequencies, keyboards might emphasize mid-bass, lead guitar provides
upper midrange, and cymbals fill in the highs.
In addition, a clear recording has adequate reproduction of each
instrument’s harmonics. That is, the high-frequency response is not
rolled off.
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Practical Recording Techniques
Smoothness
Smooth means easy on the ears, not harsh, uncolored. Sibilant sounds are
clear but not piercing. A smooth, effortless sound allows relaxation; a
strained or irritating sound causes muscle tension in the ears or body.
Smoothness is a lack of sharp peaks or dips in the frequency response, as
well as a lack of excessive boost in the midrange or upper midrange. It
is also low distortion, such as provided by a 24-bit recording.
Presence
Presence is the apparent sense of closeness of the instruments—a feeling
that they are present in the listening room. Synonyms are clarity, detail,
and punch.
Presence is achieved by close miking, overdubbing, and using
microphones with a presence peak or emphasis around 5 kHz. Using less
reverb and effects can help. Upper-midrange boost helps, too. Most
instruments have a frequency range that, if boosted, makes the instrument stand out more clearly or become better defined. Presence sometimes conflicts with smoothness because presence often involves an
upper-midrange boost, while a smooth sound is free of such emphasis.
You have to find a tasteful compromise between the two.
Spaciousness
When the sound is spacious or airy, there is a sense of air around the
instruments. Without air or ambience, instruments sound as if they are
isolated in stuffed closets. (Sometimes, though, this is the desired effect.)
You achieve spaciousness by adding reverb, recording instruments in
stereo, using room mics, or miking farther away.
Sharp Transients
The attack of cymbals and drums generally should be sharp and clear. A
bass guitar and piano may or may not require sharp attacks, depending
on the song.
Tight Bass and Drums
The kick drum and bass guitar should “lock” together so that they sound
like a single instrument—a bass with a percussive attack. The drummer
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Judging Sound Quality
14
and bassist should work out their parts together so they hit accents simultaneously, if this is desired.
To further tighten the sound, damp the kick drum and record the
bass direct. Rap music, however, has its own sound—the kick drum
usually is undamped and boomy, sometimes with short reverb added.
Equalize the kick and bass in complementary ways so that they don’t
mask each other; for example:
Kick: Boost 60 to 80 Hz, cut 150 to 400 Hz, boost 3 kHz.
Bass: Cut 60 to 80 Hz, boost 120 to 150 Hz, boost 900 Hz.
Wide and Detailed Stereo Imaging
Stereo means more than just left and right. Usually, tracks should be
panned to many points across the stereo stage between the monitor
speakers. Some instruments should be hard-left or hard-right, some
should be in the center, others should be half-left or half-right. Try to
achieve a stereo stage that is well balanced between left and right (Figure
14.2). Instruments that occupy the same frequency range can be made
more distinct by panning them to opposite sides of center.
You may want some tracks to be unlocalized. Backup choruses and
strings should be spread out rather than appearing as point sources.
Stereo keyboard sounds can wander between speakers. A lead-guitar solo
can have a fat, spacious sound.
There should also be some front-to-back depth. Some instruments
should sound close or up front; others should sound farther away. Use
different miking distances or different amounts of reverb on various
tracks.
Figure 14.2
An example of image placement between speakers.
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If you want the stereo imaging to be realistic (for a jazz combo, for
example), the reproduced ensemble should simulate the spatial layout of
the live ensemble. If you’re sitting in an audience listening to a jazz
quartet, you might hear drums on the left, piano on the right, bass in the
middle, and sax slightly right. The drums and piano are not point sources,
but are somewhat spread out. If spatial realism is the goal, you should
hear the same ensemble layout between your speakers. On some commercial CDs, the piano and drums are spread all the way between
speakers—an interesting effect, but unrealistic.
Pan-potted mono tracks often sound artificial in that each instrument sounds isolated in its own little space. It helps to add some stereo
reverberation around the instruments to “glue” them together.
Often, TV mixes are heard in mono. Hard-panned signals sound
weak in mono relative to center-panned signals. So pan sound sources to
3 and 9 o’clock, not hard-right and hard-left.
Wide but Controlled Dynamic Range
Dynamic range is the range of volume levels from softest to loudest. A
recording with a wide dynamic range becomes noticeably louder and
softer, adding excitement to the music. To achieve this, don’t add too
much compression (automatic volume control). An overly compressed
recording sounds squashed—crescendos and quiet interludes lose their
impact, and the sound becomes fatiguing.
Vocals often need some compression or gain-riding because they
have more dynamic range than the instrumental backup. A vocalist may
sing too loudly and blast the listener, or sing too softly and become buried
in the mix. A compressor can even out these extreme level variations,
keeping the vocals at a constant loudness. Bass guitar also can benefit
from compression.
Interesting Sounds
The recorded sound may be too flat or neutral, lacking character or color.
In contrast, a recording with creative production has unique musical
instrument sounds, and typically uses effects. Some of these are equalization, echo, reverberation, doubling, chorus, flanging, compression, distortion, and stereo effects.
Making sounds interesting or colorful can conflict with accuracy or
fidelity. That’s okay, but you should know the trade-off.
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Suitable Production
The way a recording sounds should imply the same message as the
musical style or lyrics. In other words, the sound should be appropriate
for the particular tune being recorded.
For example, some rock music is rough and raw. The sound should
be, too. A clean, polished production doesn’t always work for highenergy rock “n” roll. There might even be a lot of leakage or ambience to
suggest a garage studio or nightclub environment. The role of the drums
is important, so they should be loud in the mix. The toms should ring, if
that is desired.
New Age, disco, rhythm and blues, contemporary Christian, or
pop music is slickly produced. The sound is usually tight, smooth, and
spacious.
Actually, each style of music is not locked into a particular style of
production. You tailor the sound to complement the music of each individual tune. Doing this may break some of the guidelines of good sound,
but that’s usually okay as long as the song is enhanced by its sonic
presentation.
Good Sound in a Classical-Music Recording
As with pop music, classical music should sound clean, wide-range, and
tonally balanced. But because classical recordings are meant to sound
realistic—like a live performance—they also require good acoustics, a
natural balance, tonal accuracy, suitable perspective, and accurate stereo
imaging (see Chapter 18).
Good Acoustics
The acoustics of the concert hall or recital hall should be appropriate for
the style of music to be performed. Specifically, the reverberation time
should be neither too short (dry) nor too long (cavernous). Too short a
reverberation time results in a recording without spaciousness or
grandeur. Too long a reverberation time blurs notes together, giving a
muddy, washed-out effect. Ideal reverberation times are around 1.2
seconds for chamber music or soloists, 1.5 seconds for symphonic works,
and 2 seconds for organ recitals. To get a rough idea of the reverb time
of a room, clap your hands once, loudly, and count the seconds it takes
for the reverb to fade to silence.
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A Natural Balance
When a recording is well balanced, the relative loudness of instruments
is similar to that heard in an ideal seat in the audience area. For example,
violins are not too loud or soft compared to the rest of the orchestra;
harmonizing or contrapuntal melody lines are in proportion.
Generally, the conductor, composer, and musicians balance the
music acoustically, and you capture that balance with your stereo mic
pair. But sometimes you need to mike certain instruments or sections to
enhance definition or balance. Then you mix all the mics. In either case,
consult the conductor for proper balances.
Tonal Accuracy
The reproduced timbre or tone quality should match that of live instruments. Fundamentals and harmonics should be reproduced in their
original proportion.
Suitable Perspective
Perspective is the sense of distance of the performers from the listener—
how far away the stage sounds. Do the performers sound like they’re
eight rows in front of you, in your lap, or in another room?
The style of music suggests a suitable perspective. Incisive, rhythmically motivated works (such as Stravinsky’s “Rite of Spring”) sound
best with closer miking; lush, romantic pieces (a Bruckner symphony) are
best served by more distant miking. The chosen perspective depends on
the taste of the producer.
Closely related to perspective is the amount of recorded ambience
or reverberation. A good miking distance yields a pleasing balance of
direct sound from the orchestra and ambience from the concert hall.
Accurate Imaging
Reproduced instruments should appear in the same relative locations as
they were in the live performance. Instruments in the center of the ensemble should be heard in the center between the speakers; instruments at
the left or right side of the ensemble should be heard from the left or right
speaker. Instruments halfway to one side should be heard halfway off
center, and so on. A large ensemble should spread from speaker to
speaker, while a quartet or soloist can have a narrower spread.
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It’s important to sit equidistant from the speakers when judging
stereo imaging, otherwise the images shift toward the side on which
you’re sitting. Sit as far from the speakers as they are spaced apart. Then
the speakers appear to be 60 degrees apart, which is about the same angle
an orchestra fills when viewed from the typical ideal seat in the audience
(tenth row center, for example).
The reproduced size of an instrument or instrumental section should
match its size in real life. A guitar should be a point source; a piano or
string section should have some stereo spread. Each instrument’s location should be as clearly defined as it was heard from the ideal seat in
the concert hall.
Reproduced reverberation (concert-hall ambience) should surround
the listener, or at least it should spread evenly between the speakers. Surround-sound technology is needed to make the recorded ambience surround the listener, although spaced-microphone recordings have some of
this effect. Accurate imaging is illustrated in Figure 14.3.
There should be a sense of stage depth, with front-row instruments
sounding closer than back-row instruments.
Figure 14.3 With accurate imaging, the sound-source location and size, and
the reverberant field, are reproduced during playback.
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Training Your Hearing
The critical process is easier if you focus on one aspect of sound reproduction at a time. You might concentrate first on the tonal balance—try
to pinpoint what frequency ranges are being emphasized or slighted.
Next listen to the mix, the clarity, and so on. Soon you have a lengthy
description of the sound quality of your recording.
Developing an analytical ear is a continuing learning process.
Train your hearing by listening carefully to recordings—both good
and bad. Make a checklist of all the qualities mentioned in this
chapter. Compare your own recordings to live instruments and to commercial recordings. Check out the Golden-Ear ear training CDs at
www.moultonlabs.com/gold.htm.
A pop-music record that excels in all the attributes of good sound is
The Sheffield Track Record (Sheffield Labs, Lab 20), engineered and produced by Bill Schnee. In effect, it’s a course in state-of-the-art sound—
required listening for any recording engineer or producer.
Another record with brilliant production is The Nightfly by Donald
Fagen (Warner Brothers 23696-2), engineered by Roger Nichols, Daniel
Lazerus, and Elliot Scheiner, produced by Gary Katz, and mastered by
Bob Ludwig. This recording, and Steely Dan recordings by Roger
Nichols, sound razor sharp, very tight and clear, elegant, and tasteful;
and the music just pops out of the speakers.
The following listings are more examples of outstanding rock production, and set high standards:
Songs:
“I Need Somebody,” by Bryan Adams; producer, Bob
Clearmountain
“The Power of Love,” by Huey Lewis & The News; producer, Huey
Lewis & The News
Albums:
90125, by Yes; producer, Trevor Horn
Synchronicity, by The Police; producer, Hugh Padgham and The
Police
Dark Side of the Moon, by Pink Floyd; producer, Alan Parsons
Thriller, by Michael Jackson; engineer, Bruce Swedien; producer,
Quincy Jones
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Avalon, by Roxy Music; engineer, Bob Clearmountain; producer,
Roxy Music
Come Away With Me, by Norah Jones; engineer, Jay Newland
Genius Loves Company, by Ray Charles; several engineers
Give, by The Bad Plus; engineer, Tchad Blake
Live in Paris and The Look of Love, by Diana Krall; engineer, Al Schmitt
Smile, by Brian Wilson; engineer, Mark Linett
Then there are the incredibly clean recordings of Tom Jung
(with DMP records) and George Massenberg. Some classical-music
recordings with outstanding sound are on the Telarc, Delos and Chesky
labels. You can learn a lot by emulating these superb recordings and
many others.
Once you’re making recordings that are competent technically—
clean, natural, and well mixed—the next stage is to produce imaginative
sounds. You’re in command; you can tailor the mix to sound any way
that pleases you or the band you’re recording. The supreme achievement
is to produce a recording that is a sonic knockout, beautiful and/or
thrilling.
Troubleshooting Bad Sound
Now you know how to recognize good sound, but can you recognize bad
sound? Suppose you’re monitoring a recording in progress, or listening
to a recording you’ve already made. Something doesn’t sound right. How
can you pinpoint what’s wrong, and how can you fix it?
The rest of this chapter includes step-by-step procedures to solve
audio-related problems. Read down the list of “bad sound” descriptions
until you find one matching what you hear. Then try the solutions until
your problem disappears. Only the most common symptoms and cures
are mentioned; console maintenance is not covered.
This troubleshooting guide is divided into four main sections:
1.
2.
3.
4.
Bad sound on all recordings (including those from other studios)
Bad sound on playback only (the mixer output sounds all right)
Bad sound in a pop-music recording
Bad sound in a classical-music recording
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Before you start, check for faulty cables and connectors. Also check
all control positions; rotate knobs, and flip switches to clean the contacts,
and clean connectors with De-Oxit from Caig Labs.
Bad Sound on All Recordings
If you have bad sound on all your recordings, including those from other
studios, follow this checklist to find the problem:
• Upgrade your monitor system.
• Adjust tweeter and woofer controls on speakers.
• Adjust the relative gains of tweeter and woofer amplifiers in a
bi-amped system.
• Relocate speakers.
• Improve room acoustics.
• Equalize the monitor system.
• Try different speakers.
• Upgrade the power amp and speaker cables.
• Monitor at a moderate listening volume, such as 85 dBSPL. We hear
less bass and treble in a program if it is monitored at a low volume,
and vice versa. If we hear too little bass due to monitoring at a low
level, we might mix in too much bass.
Bad Sound on Playback Only
You might have bad sound on your playback only, but your mixer output
sounds okay. If DAT tape playback has glitches or drop-outs, try these
steps:
• Clean the recorder with a dry cleaning tape.
• Before recording, fast-forward the tape to the end and rewind it to
the top.
• Use better tape.
• Format videocassettes nonstop from start to finish.
If a hard-drive recording has glitches or drop-outs on playback, try
this:
• Increase the latency setting in your recording software.
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• Follow the tips in the section Optimizing Your Computer for Digital
Audio in Appendix B.
If a digital recording sounds distorted, these suggestions might help:
• Keep the recording level as high as possible, but don’t exceed 0 dBFS
(decibels Full Scale).
• Avoid clipping in effects plug-ins.
• Record at a higher sampling rate or higher bit depth.
• Avoid sampling-rate conversion.
• Apply dither when going from a high bit depth to a lower bit depth.
Bad Sound in a Pop-Music Recording Session
Sometimes you have bad sound in a pop-music recording session.
Muddiness (Leakage)
If the sound is muddy from excessive leakage, try the following:
• Place the microphones closer to their sound sources.
• Spread the instruments farther apart to reduce the level of the
leakage.
• Place the instruments closer together to reduce the delay of the
leakage.
• Use directional microphones (such as cardioids).
• Overdub the instruments.
• Record the electric instruments direct.
• Use baffles (goboes) between instruments.
• Deaden the room acoustics (add absorptive material or flexible
panels).
• Filter out frequencies above and below the spectral range of each
instrument. Be careful or you’ll change the sound of the instrument.
• Turn down the bass amp in the studio, or monitor the bass with
headphones instead.
Muddiness (Excessive Reverberation)
If the sound is muddy due to excessive reverberation, try these steps:
• Reduce the effects-send levels or effects-return levels. Or don’t use
effects until you figure out what the real problem is.
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•
•
•
•
Place the microphones closer to their sound sources.
Use directional microphones (such as cardioids).
Deaden the room acoustics.
Filter out frequencies below the fundamental frequency of each
instrument.
Muddiness (Lacks Highs)
If your sound is muddy and lacks highs, or has a dull or muffled sound,
try the following:
• Use microphones with better high-frequency response, or use condenser mics instead of dynamics.
• Change the mic placement. Put the mic in a spot where there are sufficient high frequencies. Keep the high-frequency sources (such as
cymbals) on-axis to the microphones.
• Use small-diameter microphones, which generally have a flatter
response off-axis.
• Boost the high-frequency equalization or cut slightly around 300 Hz.
• Change musical instruments; replace guitar strings; replace drum
heads. (Ask the musicians first!)
• Use an enhancer signal processor, but watch out for noise.
• Use a direct box on the electric bass. Have the bassist play percussively or use a pick if the music requires it. When compressing the
bass, use a long attack time to allow the note’s attack to come
through. (Some songs don’t require sharp bass attacks—do whatever’s right for the song.)
• Damp the kick drum with a pillow, folded towel or blanket, and
mike it next to the center of the head near the beater. Use a wooden
or plastic beater if the song and the drummer allow it.
• Don’t plug an electric guitar directly into a mic input. Use a direct
box or a high-impedance input.
Muddiness (Lacks Clarity)
If your sound is muddy because it lacks clarity, try these steps:
• Consider using fewer instruments in the musical arrangement.
• Equalize instruments differently so that their spectra don’t overlap.
• Try less reverberation.
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• Using equalizers, boost the presence range of instruments that lack
clarity. Or cut 1 to 2 dB around 300 Hz.
• In a reverb unit, add about 30 to 100 msec of pre-delay.
• Pan similar-sounding instruments to opposite sides.
Distortion
If you hear distortion when monitoring the mics in a pop-music recording, try the following:
• Increase input attenuation (reduce input gain), or plug in a pad
between the microphone and mic input.
• Readjust gain-staging: Set faders and pots to their design centers
(shaded areas).
• If you still hear distortion, switch in the pad built into the microphone (if any).
• Check connectors for stray wires and bad solder joints.
• Unplug and plug-in connectors. Clean them with Caig Labs De-Oxit
or Pro Gold.
Tonal Imbalance
If you have bad tonal balance—the sound is boomy, dull, or shrill, for
example—follow these steps:
• Change musical instruments; change guitar strings; change reeds,
etc.
• Change mic placement. If the sound is too bassy with a directional
microphone, you may be getting proximity effect. Mike farther away
or roll off the excess bass.
• Use the 3 : 1 rule of mic placement to avoid phase cancellations.
When you mix two or more mics to the same channel, the distance
between mics should be at least three times the mic-to-source
distance.
• Try another microphone. If the proximity effect of a cardioid mic is
causing a bass boost, try an omnidirectional mic instead.
• If you must place a microphone near a hard, reflective surface, try a
boundary microphone on the surface to prevent phase cancellations.
• If you’re recording a singer/guitarist, delay the vocal mic signal by
about 1 msec.
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• Change the equalization. Avoid excessive boost. Maybe cut slightly
around 300 Hz if the sound is muddy, or cut around 3 kHz if the
sound is harsh.
• Use equalizers with a broad bandwidth, rather than a narrow,
peaked response.
Lifelessness
If your pop-music recording has a lifeless sound and is unexciting, these
steps might help you solve it:
• Work on the live sound of the instruments in the studio to come up
with unique effects.
• Add effects: reverberation, echo, exciter, doubling, equalization, etc.
• Use and combine recording equipment in unusual ways.
• Try overdubbing little vocal licks or synthesized sound effects.
If your sound seems lifeless due to dry or dead acoustics, try these:
• If leakage is not a problem, put microphones far enough from instruments to pick up wall reflections. If you don’t like the sound this
produces, try the next suggestion.
• Add reverb or echo to dry tracks. (Not all tracks require reverberation. Also, some songs may need very little reverberation so that
they sound intimate.)
• Use omnidirectional microphones.
• Add hard, reflective surfaces in the studio, or record in a hardwalled room.
• Allow a little leakage between microphones. Put mics far enough
from instruments to pick up off-mic sounds from other instruments.
Don’t overdo it, though, or the sound becomes muddy and track
separation becomes poor.
Noise (Hiss)
Sometimes your pop-music recording has extra noise on it. If your sound
has hiss, try these:
• Check for noisy guitar amps or keyboards.
• Switch out the pad built into the microphone (if any).
• Reduce mixer input attenuation (increase input gain).
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• Use a more sensitive microphone.
• Use an impedance-matching adapter (a low- to high-Z step-up transformer) between microphones and phone-jack mic inputs.
• Use a quieter microphone (one with low self-noise).
• Increase the sound pressure level at the microphone by miking
closer. If you’re using PZMs, mount them on a large surface or in a
corner.
• Apply any high-frequency boost during recording, rather than
during mixdown.
• If possible, feed recorder tracks from mixer direct outs or insert
sends instead of group or bus outputs.
• Use a lowpass filter (high-cut filter).
• As a last resort, use a noise gate.
Noise (Rumble)
If the noise is a low-frequency rumble, follow these steps:
• Reduce air-conditioning noise or shut off the air conditioning
temporarily.
• Use a highpass filter (low-cut filter) that is set around 40 to 80 Hz.
• Use microphones with limited low-frequency response.
• See the section Noise (Thumps) below.
Noise (Thumps)
•
•
•
•
Change the microphone position.
Change the musical instrument.
Use a highpass filter set around 40 to 80 Hz.
If the cause is mechanical vibration traveling up the mic stand, put
the mic in a shock-mount stand adapter, or place the mic stand on
some carpet padding. Try to use a microphone that is less susceptible to mechanical vibration, such as an omnidirectional mic or a unidirectional mic with a good internal shock mount.
• Use a microphone with a limited low-frequency response.
• If the cause is piano pedal thumps, also try working on the pedal
mechanism.
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Hum
Hum is a subject in itself. See the section Hum Prevention at the end of
Chapter 4.
Pop
Pops are explosive breath sounds in a vocalist’s microphone. If your popmusic recording has pops, try these solutions:
• Place the microphone above or to the side of the mouth.
• Place a foam windscreen (pop filter) on the microphone.
• Stretch a silk stocking over a crochet hoop, and mount it on a mic
stand a few inches from the microphone (or use an equivalent commercial product).
• Place the microphone farther from the vocalist.
• Use a microphone with a built-in pop filter (ball grille).
• Use an omnidirectional microphone, because it is likely to pop less
than a directional (cardioid) microphone.
• Switch in a highpass filter (low-cut filter) set around 80 Hz.
Sibilance
Sibilance is an overemphasis of “s” and “sh” sounds. If you are getting
sibilance on your pop-music recording, try these steps:
• Use a de-esser signal processor or plug-in. Or use a multiband compressor, and compress the range from 5 to 10 kHz.
• Place the microphone farther from the vocalist.
• Place the microphone toward one side of the vocalist, rather than
directly in front.
• Cut equalization in the range from 5 to 10 kHz.
• Change to a duller sounding microphone.
Bad Mix
Some instruments or voices are too loud or too quiet. To improve a bad
mix, try the following:
• Change the mix. (Maybe change the mix engineer!)
• Compress vocals or instruments that occasionally get buried.
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• Change the equalization on certain instruments to help them stand
out.
• During mixdown, continuously change the mix to highlight certain
instruments according to the demands of the music.
• Change the musical arrangement so that different musical parts
don’t play at the same time. That is, consider having a call-andresponse arrangement (fill-in-the-holes) instead of everything
playing at once, all the time.
Unnatural Dynamics
When your pop-music recording has unnatural dynamics, loud sounds
don’t get loud enough. If this happens, try these steps:
• Use less compression or limiting.
• Avoid overall compression.
• Use multiband compression on the stereo mix instead of wideband
(full-range) compression.
Isolated Sound
If some of the instruments on your recording sound too isolated, as if
they are not in the same room as the others, follow these steps:
• In general, allow a little crosstalk between the left and right channels. If tracks are totally isolated, it’s hard to achieve the illusion that
all the instruments are playing in the same room at the same time.
You need some crosstalk or correlation between channels. Some
right-channel information should leak into the left channel, and vice
versa.
• Place microphones farther from their sound sources to increase
leakage.
• Use omnidirectional mics to increase leakage.
• Use stereo reverberation or echo.
• Pan effects returns to the channel opposite the channel of the dry
sound source.
• Pan extreme left-and-right tracks slightly toward center.
• Make the effects-send levels more similar for various tracks.
• To give a lead-guitar solo a fat, spacious sound, use a stereo chorus.
Or send its signal through a delay unit, pan the direct sound hard
left, and pan the delayed sound hard right.
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Lack of Depth
If the mix lacks depth, try these steps:
• Achieve depth by miking instruments at different distances.
• Use varied amounts of reverberation on each instrument. The higher
the ratio of reverberant sound to direct sound, the more distant the
track sounds.
Bad Sound in a Classical-Music Recording
Check the following procedures if you have problems recording classical
music:
Too Dead
If the sound in your classical recording is too dead—there is not enough
ambience or reverberation—try these measures to solve the problem:
• Place the microphones farther from the performers.
• Use omnidirectional microphones.
• Record in a concert hall with better acoustics (longer reverberation
time).
• Turn up the hall mics (if used).
• Add artificial reverberation.
Too Close
If the sound is too detailed, too close, or too edgy, follow these steps:
• Place the microphones farther from the performers.
• Place the microphones lower or on the floor (as with a boundary
microphone).
• Roll off the high frequencies.
• Use mellow-sounding microphones (many ribbon mics have this
quality).
• Turn up the hall mics (if used).
• Increase the reverb-send level.
Too Distant
If the sound is distant and there is too much reverberation, these steps
might help:
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Judging Sound Quality
•
•
•
•
•
Place the microphones closer to the performers.
Use directional microphones (such as cardioids).
Record in a concert hall that is less live (reverberant).
Turn down the hall mics (if used).
Decrease the reverb-send level.
Stereo Spread Too Narrow or Too Wide
If your classical-music recording has a narrow stereo spread, try these
steps:
• Angle or space the main microphone pair farther apart.
• If you’re doing mid-side stereo recording, turn up the side output
of the stereo microphone.
• Place the main microphone pair closer to the ensemble.
If the sound has excessive stereo spread (or “hole-in-the-middle”),
try the following:
• Angle or space the main microphone pair closer together.
• If you’re doing mid-side stereo recording, turn down the side output
of the stereo microphone.
• In spaced-pair recording, add a microphone midway between the
outer pair, and pan its signal to the center.
• Place the microphones farther from the performers.
Lack of Depth
Try the following to bring more depth into your classical-music
recording:
• Use only a single pair of microphones out front. Avoid multimiking.
• If you must use spot mics, keep their level low in the mix.
• Add more artificial reverberation to the distant instruments than to
the close instruments.
Bad Balance
If your classical-music recording has bad balance, try the following:
• Place the microphones higher or farther from the performers.
• Ask the conductor or performers to change the instruments’ written
dynamics. Be tactful!
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• Add spot microphones close to instruments or sections needing reinforcement. Mix them in subtly with the main microphones’ signals.
Muddy Bass
If your recording has a muddy bass sound, follow these steps:
• Aim the bass-drum head at the microphones.
• Put the microphone stands and bass-drum stand on resilient isolation mounts (such as a carpet pad), or place the microphones in
shock-mount stand adapters.
• Roll off the low frequencies or use a highpass filter set around 40 to
80 Hz.
• Use artificial reverb with a shorter decay time at low frequencies.
• Record in a concert hall with less low-frequency reverberation.
Rumble
Sometimes your classical-music recording picks up rumble from air conditioning, trucks, and other sources. Try the following to clear this up:
•
•
•
•
•
•
Check the hall for background rumble problems.
Temporarily shut off the air conditioning.
Record in a quieter location.
Use a highpass filter set around 40 to 80 Hz.
Use microphones with limited low-frequency response.
Mike closer and add artificial reverb.
Distortion
If your classical-music recording has distortion, try the following:
•
•
•
•
•
Switch in the pads built into the microphones (if any).
Increase the mixer input attenuation (turn down the input trim).
Check connectors for stray wires or bad solder joints.
Avoid sample-rate conversion.
Apply dithering when going from 24 to 16 bits.
Bad Tonal Balance
Bad tonal balance expresses itself in a sound that is too dull, too bright,
or colored. If your recording has this problem, follow these steps:
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• Change the microphones. Generally, use flat-response microphones
with minimal off-axis coloration.
• Follow the 3 : 1 rule mentioned in Chapter 7.
• If a microphone must be placed near a hard, reflective surface, use
a boundary microphone on the surface to prevent phase cancellations between direct and reflected sounds.
• Adjust equalization.
• Place the mics at a reasonable distance from the ensemble (too-close
miking sounds shrill).
• Avoid mic positions that pick up standing waves or room modes.
Experiment with small changes in mic position.
This chapter describes a set of standards for good sound quality in
both popular- and classical-music recordings. These standards are somewhat arbitrary, but the engineer and producer need guidelines to judge
the effectiveness of the recording. The next time you hear something you
don’t like in a recording, the lists in this chapter will help you define the
problem and find a solution.
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SESSION PROCEDURES,
EDITING, MASTERING, AND
CD BURNING
“We’re rolling. Take One.” These words begin the recording session. It
can be an exhilarating or an exasperating experience, depending on how
smoothly you run it.
The musicians need an engineer who works quickly yet carefully.
Otherwise, they may lose their creative inspiration while waiting for the
engineer to get it together. And the client, paying by the hour, wastes
money unless the engineer has prepared for the session in advance.
This chapter describes how to conduct a multitrack recording
session. These procedures should help you keep track of things and run
the session efficiently.
There are some spontaneous sessions, especially in home studios,
that just “grow organically” without advance planning. The instrumentation is not known until the song is done! You just try out different
musical ideas and instruments until you find a pleasing combination.
In this way, a band that has its own recording gear can afford to take
the time to find out what works musically before going into a professional
studio. In addition, if the band is recording itself where it practices, the
microphone setup and some of the console settings can be more or less
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Practical Recording Techniques
permanent. This chapter, however, describes procedures usually followed
at professional studios, where time is money.
Preproduction
Long before the session starts, you’re involved in preproduction—planning what you’re going to do at the session, in terms of overdubbing,
track assignments, instrument layout, and mic selection.
Instrumentation
The first step is to find out from the producer or the band what the instrumentation will be and how many tracks will be needed. Make a list of
the instruments and vocals that will be used in each song. Include such
details as the number of tom toms, whether acoustic or electric guitars
will be used, and so on.
Recording Order
Next, decide which of these instruments will be recorded at the same time
and which will be overdubbed one at a time. It’s common to record the
instruments in the following order, but there are always exceptions:
1. Loud rhythm instruments—bass, drums, electric guitar, electric
keyboards
2. Quiet rhythm instruments—acoustic guitar, piano
3. Lead vocal and doubled lead vocal (if desired)
4. Backup vocals (in stereo)
5. Overdubs—solos, percussion, synthesizer, sound effects
6. Sweetening—horns, strings
The lead vocalist usually sings a reference vocal or scratch vocal along
with the rhythm section so that the musicians can get a feel for the tune
and keep track of where they are in the song. The vocalist’s performance
in this case is recorded but probably is redone later.
In a MIDI studio, a typical order might be:
1. Drum machine (playing programmed patterns)
2. Synthesizer bass sound
3. Synthesizer chords
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Session Procedures, Editing, Mastering, and CD Burning
15
4. Synth melody
5. Synth solos, extra parts
6. Vocals and miked solos
Track Assignments
Now you can plan your track assignments. Decide what instruments will
go on which tracks of the multitrack recorder. The producer may have a
fixed plan already.
What if you have more instruments than tracks? Decide what groups
of instruments to put on each track. In a 4-track recording, for example,
you might record a stereo mix of the rhythm section on tracks 1 and 2,
then overdub vocals and solos on tracks 3 and 4. Or you might put guitars
on track 1, bass and drums on track 2, vocals on track 3, and keyboards
on track 4.
Remember that when several instruments are assigned to the same
track, you can’t separate their images in the stereo stage. That is, you can’t
pan them to different positions—all the instruments on one track sound
as if they’re occupying the same point in space. For this reason, you may
want to do a stereo mix of the rhythm section on tracks 1 and 2, for
instance, and then overdub vocals and solos on tracks 3 and 4.
It’s possible to overdub more than four parts on a 4-track recorder.
To do this, bounce or ping-pong several tracks onto one. Your recorder
manual describes this procedure.
If you have many tracks available, leave several tracks open for
experimentation. For example, you can record several takes of a vocal
part using a separate track for each take, so that no take is lost. Then
combine the best parts of each take into a single final performance on one
track. Most DAWs let you do these extra takes on virtual tracks. It’s also
a good idea to record the monitor mix on one or two unused tracks. The
recorded monitor mix can be used as a cue mix for overdubs, or to make
a recording for the client to take home and evaluate.
Session Sheet
Once you know what you’re going to record and when, you can fill out
a session sheet (Figure 15.1). This simple document is adequate for home
studios. “OD” indicates an overdub. Note the recorder-counter time for
each take, and circle the best take.
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Practical Recording Techniques
SONG: Escape to Air Island
TRACK
1
2
3
4
5
6
7
8
INSTRUMENT
BASS
KICK
DRUMS
LEAD VOC OD
HARM. VOC OD
LEAD GUIT OD
KEYS L
KEYS R
MICROPHONE
DIRECT
AKG D-112
CROWN GLM-100
STUDIO PROJECTS B1
STUDIO PROJECTS B1
SHURE SM57
DIRECT
DIRECT
TAKE 1 03:21 - 06:18 FS
2 06:25 - 09:24 INC
3 10:01 - 13:02
Figure 15.1
A session sheet for a home studio.
Production Schedule
In a professional recording studio, the planned sequence of recording
basic tracks and overdubs is listed on a production schedule (Figure 15.2).
Track Sheet
Another document used in a pro studio is the track sheet or multitrack
log (Figure 15.3). Write down which instrument or vocal goes on which
track. The track sheet also has blanks for other information. If you are
using a DAW, you can enter this information by typing it on-screen.
Microphone Input List
Make up a microphone input list similar to that seen in Table 15.1.
Later you will place this list by the mic snake box and by the mixing
console.
Be flexible in your microphone choices—you may need to experiment with various mics during the session to find one giving the best
sound with the least console equalization. During lead-guitar overdubs,
for example, you can set up a direct box, three close-up microphones, and
one distant microphone—then find a combination that sounds best.
Find out what sound the producer wants—a “tight” sound; a “loose,
live” sound; an accurate, realistic sound. Ask to hear recordings having
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Session Procedures, Editing, Mastering, and CD Burning
Figure 15.2
15
A production schedule.
Table 15.1
A Microphone Input List
Input
Instrument
Microphone
1
2
3
4
5
6
7
8
9
10
11
12
Bass
Kick
Snare
Overhead L
Overhead R
High toms
Floor tom
Electric lead guitar
Electric lead guitar
Piano treble
Piano bass
Scratch vocal
Direct
EV N/D868
AKG C451
Shure SM81
Shure SM81
Sennheiser MD421-II
Sennheiser MD421
Shure SM57
Shure SM57
Crown PZM-6D
Crown PZM-6D
Beyer M88
347
Figure 15.3
348
A track sheet (multitrack recorder log).
Session Procedures, Editing, Mastering, and CD Burning
15
the kind of sound the producer desires. Try to figure out what techniques
were used to create those sounds, and plan your mic techniques
and effects accordingly. Tips on choosing a microphone are given in
Chapter 6.
Instrument Layout Chart
Work out an instrument layout chart, indicating where each instrument will be located in the studio, and where baffles and isolation booths
will be used (if any). In planning the layout, make sure that all the musicians can see each other and are close enough together to play as an
ensemble.
Setting Up the Studio
About an hour before the session starts, clean up the studio to promote
a professional atmosphere. Lay down rugs and place AC power boxes
according to your layout chart.
Now position the baffles (if any) on top of what has gone before. Put
out chairs and stools according to the layout. Add music stands and
music-stand lights. Run headphone cables from each artist’s location to
the headphone junction box in the studio.
Place mic stands approximately where they will be used. Wrap one
end of a microphone cable around each microphone-stand boom, leaving
a few extra coils of cable near the mic-stand base to allow slack for
moving. Run the rest of the cable back to the mic input panel or snake
box. Plug each cable into the appropriate wall-panel or snake-box input
according to your mic input list.
Some engineers prefer to run cables in reverse order, connecting to
the input panel first and running the cable out to the microphone stand.
That procedure leaves less of a confusing tangle at the input panel where
connections might be changed.
Now set up the microphones. Check each mic to make sure its
switches are in the desired positions. Put the mics in their stand adapters,
connect the cables, and balance the weight of each boom against the
microphone.
Finally, connect the musicians’ headphones for cueing. Set up a spare
cue line and microphone for last-minute changes.
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Practical Recording Techniques
Setting Up the Control Room
Having prepared the studio, run through the checklist below to make
sure the control room is ready for the session:
1. Pull all the patch cords from the patch panel.
2. If necessary, patch console bus 1 to recorder track 1, bus 2 to track
2, and so on.
3. Check out all the equipment to make sure it’s working.
4. Label the blank recording medium with the artist, date, and reel
number. If you’re recording on a DAW, type in this information on
screen along with the file name.
5. If you’re using an MDM, insert the blank tape.
6. Normalize or zero the console by setting all switches and knobs to
“off,” “zero,” or “flat” so they have no effect.
7. Switch on phantom powering for condenser microphones.
8. Set the console input-selector switches (if any) to “mic” or “line” as
needed.
9. Attach a designation strip of masking tape across the front of the
console. Referring to your mic input list, write on the strip the instrument each fader affects (bass, kick, guitar, etc.). Also label the submasters and monitor-mixer knobs according to what is assigned to
them.
10. Turn up the monitor system. Carefully bring up each fader one at a
time and listen to each microphone. You should hear normal studio
noise. If you hear any problems such as dead or noisy microphones,
hum, bad cables, or faulty power supplies, correct them before the
session.
11. Verify the mic input list. Have an assistant scratch each mic grille
with a fingernail and identify the instrument the microphone is
intended to pick up. If you have no assistant, listen on headphones
as you turn up one mic at a time and listen for background noise.
12. Check all the cue headphones by playing a tone or music through
them and listening while wiggling each cable.
Session Overview
This is the typical sequence of events:
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Session Procedures, Editing, Mastering, and CD Burning
15
1. For efficiency, record the basic rhythm tracks for several songs on
the first session.
2. Do the overdubs for all the songs in a dubbing session.
3. Mix all the tunes in a mixdown session.
4. Edit the tunes and master the album.
After the musicians arrive, allow them 1/2 hour to 1 hour free setup
time for seating, tuning, and mic placement. Show them where to sit, and
work out new seating arrangements if necessary to make them more
comfortable.
Once the instruments are set up, you may want to listen to their live
sound in the studio and do what you can to improve it. A dull-sounding
guitar may need new strings, a noisy guitar amp may need new tubes,
and so on. Adjust the studio lighting for the desired mood.
Recording
Follow the mixer recording procedures described in Chapter 12. Before
you start recording, you might want to make connections to record the
monitor mix. This recording is for the producer to take home to evaluate
the performance.
When you’re ready to record the tune, briefly play a metronome to
the group at the desired tempo, or play a click track (an electronic
metronome) through the cue system. Or just let the drummer set the
tempo with stick clicks.
Start recording. Note the recorder counter time. Hit the slate button
(if any) and announce the name of the tune and the take number.
Have someone play the keynote of the song (for tuning other instruments later). Then the group leader or the drummer counts off the beat,
and the group starts playing.
The producer listens to the musical performance while the engineer
watches levels and listens for audio problems. As the song progresses,
you may need to make small level adjustments. As stated before, the
recording levels are set as high as possible without causing distortion.
Balancing the instruments at this time is done with the monitor mixer.
The monitor mix affects only what is being heard, not what is being
recorded.
The assistant engineer (if any) runs the multitrack recorder and
keeps track of the takes on the track sheet, noting the name of the tune,
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Practical Recording Techniques
the take number, and whether the take was complete (Figure 15.3). Use
a code to indicate whether the take was a false start, nearly completed, a
“keeper,” and so on.
While the song is in progress, don’t use the solo function, because
the abrupt monitoring change may disturb the producer. The producer
should stop the performance if a major flub (mistake) occurs but should
let the minor ones pass.
At the end of the song, the musicians should be silent for several
seconds after the last note. Or, if the song ends in a fade-out, the musicians should continue playing for about 30 seconds so there is enough
material for a fade-out during mixdown.
After the tune is done, you can either play it back or go on to a
second take. Set a rough mix with the aux knobs. If you connected your
multitrack to the insert jacks, use the faders to set a rough mix with EQ
and effects. The musicians will catch their flubbed notes during playback;
you just listen for audio quality.
Now record other takes or tunes. Pick the best takes. To protect your
hearing, try to limit tracking sessions to four hours or less with five hours
maximum.
Overdubbing
After recording the basic or rhythm tracks for all the tunes, add overdubs.
A musician listens to previously recorded tracks over headphones and
records a new part on an open track. Follow the overdubbing and punching in/out procedures in Chapter 12.
Composite Tracks
If several open tracks are available, you can record a solo overdub in
several takes, each on a separate track or virtual track. This is referred to
as “comping” or “recording composite tracks.” After recording all the
takes, play back the solo and assign all the overdubbed tracks to a remaining open track set in record mode. You will bounce all the solo tracks to
a composite track. Match the levels of the different takes. Then switch the
overdubbed tracks on and off (using muting), recording just the best parts
of each take. Finally, erase or archive the original tracks to free them up
for other instruments.
If you are recording on hard disk or MiniDisc, usually you can
record several takes on virtual tracks, then comp those virtual tracks
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Session Procedures, Editing, Mastering, and CD Burning
15
during mixdown. If you are recording on a computer DAW, you can
simply cut and paste the best parts of each take onto a single track, then
archive the source tracks. Cakewalk Sonar Producer lets you record
several takes on one track, view all the take waveforms as “lanes” in that
track, select the best parts of each take, and create a composite track of
those parts.
Drum Overdubs
Drum overdubs are usually done right after the rhythm session because
the microphones are already set up, and the overdubbed sound will
match the sound of the original drum track.
Overdubbing in the Control Room
To aid communications among the engineer, producer, and musician,
have the musician play in the control room while overdubbing. You
can patch a synth or electric guitar into the console through a direct
box, and feed the direct signal to a guitar amp in the studio via a cue line.
Pick up the amp with a microphone, and record and monitor the mic
signal.
Breaking Down
When the session is over, tear down the microphones, mic stands, and
cables. Put the microphones back in their protective boxes and bags. Wind
the mic cables onto a power-cable spool, connecting one cable to the next.
Wipe off the cables with a damp rag if necessary. Some engineers hang
each cable in big loops on each mic stand. Others wrap the cable “lasso
style” with every other loop reversed. You learn this on the job.
Put the labeled recording in its box. Also in the box, or in a file folder,
put the designation strips, track sheet, and take sheet. Label the box and
folder. Normally the studio keeps the multitrack master for possible
future work unless the group wants to buy or rent it.
Log the console settings by writing them in the track sheet or reading
them slowly into a portable cassette recorder. At a future session you can
play back the tape and reset the console the way it was for the original
session. Consoles or DAWs with automated mixing can store and recall
the control settings.
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Practical Recording Techniques
Mixdown
After all the parts are recorded, you’re ready for mixdown. Prepare the
console and recorders, erase noises, and play the multitrack recording
while adjusting balances, panning, equalization, reverberation, and
effects. Automate changes in the mix if possible. Once you’ve rehearsed
the mix to perfection, record it onto a 2-track recorder or your computer
hard drive. Follow the mixdown procedures in Chapter 12. Repeat for all
the song mixes.
Mastering
After recording the mixes, you can burn a CD of the mixes as they are,
or you can master an album or demo of those mixes. Mastering is the last
creative step before burning the final CD used for duplication. In mastering you edit out noises or false starts before the beginning of each song,
put the songs in the desired order, insert a few seconds of silence between
songs, and make each song the same loudness and the same tonal
balance. The object is a consistent sound from track to track, so that everything flows better and the album sounds unified. You also might try to
make the CD as loud or “hot” as possible (without destroying its sound
quality).
At this point, you have three choices:
1. If the CD will be just a reference, not a demo or album, you can burn
a CD of the unedited mixes and stop there.
2. If the CD will be a demo or album, burn a CD of the unedited mixes,
then send it to a mastering engineer for mastering.
3. Or you can edit and master the mixes yourself, then burn a CD. It
will be the CD master for duplication.
Let’s look at each option above.
Burning a Reference CD
You can use the CD-burning software that came with your computer CD
burner, or use other software. Some examples of CD-burning programs
are Roxio’s Toast, Jam, and Easy CD Creator; Ahead Software’s Nero;
Stomp’s Click ‘N Burn; Steinberg’s Clean!; My MP3 and Get it on CD;
Golden Hawk Technologies’ CDRWIN; and Cakewalk’s Pyro. Some
DAW software includes a CD-burning application.
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Session Procedures, Editing, Mastering, and CD Burning
15
Here’s the procedure:
1. The CD burning software puts 2 seconds of silence between songs.
If you want to have extra seconds of silence at the end of a song,
record the silence as part of the song’s wave file.
2. Start the CD-R recording software.
3. Select which wave files you want to put on the CD-R, drag them to
the playlist, and arrange them in the desired order. The total playing
time must be less than the CD-R length (74 or 80 minutes).
4. Set the recording settings. You can either burn a disc on-the-fly or
create a disk image. When recording on-the-fly, the computer grabs
the sound files from random locations on hard disk and puts them
in order as the CD-R does a burn. When recording a disk image, the
computer rewrites the sound files to a single, contiguous space on
your hard disk and puts them in order. Then you copy the disk
image from hard disk to CD-R. Disk image is less likely to produce
CD errors than On-the-fly.
You have a choice of transfer speed. Some CD recorders and blank
CDs can record up to 52 times normal speed. Normal speed is 172 KBps
(Bytes is capital B), double speed is 344 KBps, etc. A 52X recorder can burn
a 74-minute CD in less than 2 minutes. Some CD burners automatically
select the optimum speed based on what the blank CD-R can handle.
High speeds do not degrade sound quality seriously, but they tend to
increase errors—which the CD player may or may not correct accurately.
The recommended speed to prevent errors is 2X to 4X when making a
final master CD to be sent out for replication. But some CD recorders and
blank CD-Rs have fewer errors at higher speeds.
You might want to normalize each track. This raises the highest peak
in the track to maximum level: 0 dBFS (decibels Full Scale). Normalizing
does not make the tracks the same loudness, because loudness depends
on the average signal level, not the peak level.
5. Set the software to Disc-at-Once Mode. Start recording the CD-R.
The wave files will transfer in order to the CD-R disc. To prevent
glitches, do not multitask while the CD is recording.
CD-R discs cannot be erased and used over again, so try to make
everything right before you burn a disc. You could do a practice burn on
a CD-RW.
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Practical Recording Techniques
6. As soon as the recording is done, the display will indicate that the
table of contents is being written. Eventually, the system will beep
and eject the disc. To prevent error-causing fingerprints, be sure to
handle the disc only by the edges. Pop the disc in an audio CD
player, press Play, and check that all the tracks play correctly.
Sending Out Your CD for Mastering
You might prefer to send your CD of mixes to a good mastering engineer.
This person can listen to your program with fresh ears, then suggest processing for your album that will make it sound more commercial. He or
she is likely to have a better monitor system and better equipment than
yours. They have heard hundreds of recording projects done by others,
and know how to make your CD sonically competitive.
If you plan to have your program mastered outside, do not apply
any signal processing to your finished mixes such as editing, level
changes, compression, normalization, fades, or EQ. Let the mastering
house do it with their better equipment and software. Also, leave some
headroom by recording the finished mixes at about -3 dBFS maximum.
Deliver your mixes in the highest possible resolution, such as 96 to 192
kHz and 24 to 32 bits. If possible, create a data CD rather than an audio
CD. That is, copy the mixes’ wave files to CD, rather than creating CD
audio tracks (.cda files). The resulting data CD can be read by a CD-ROM
but cannot be played on a CD player.
To copy the mixes as data, use the data copying feature of your CD
burning program. Drag the wave files of the mixes to the playlist, then
record the CD as described in the previous section. If your CD burning
program does not support data CDs, just create an audio or music CD.
Mastering Your Own Album
Mastering can be done in your multitrack recording software, or in an
audio production program such as Steinberg Nuendo, Sony Sound Forge,
BIAS Peak, Digidesign MasterList CD, TC Works Spark, 1K Multimedia
T-Racks 24, or Magix Samplitude.
First, discuss the order of the songs on the recording. For the first
song, use a strong, accessible, up-tempo tune. Alternate keys or tempos
from song to song. The last tune should be as good as or better than the
first to leave a good final impression.
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Session Procedures, Editing, Mastering, and CD Burning
15
Mastering engineer Bob Katz offers these suggestions for song
sequencing: Create the album in sets of one to three songs of the same
tempo. Make sure the songs flow from one to the next. Here’s a suggested
song order:
1.
2.
3.
4.
5.
An up-tempo, exciting song that hooks the listener.
After a short space, an up-tempo or mid-tempo song.
After three or four songs, slow down the tempo.
Reach a climax near the end of the album.
The last song should sound relaxed and intimate, perhaps using
fewer members of the band.
Once you have decided on the order of songs, you’re ready to master
the demo or album as described below.
1. If you already recorded your mixes directly onto hard disk as stereo
wave files, skip to Step 4.
2. If your song mixes are wave files on CD-R, put the CD-R in your
CD-ROM drive and copy each song to your hard drive. Then go to
Step 4. If your song mixes are audio tracks (.cda files) on a CD-R,
convert each track to a wave file on your hard drive. This process
requires CD-audio-to-wave conversion software. Skip to Step 4.
3. If your mixes are on a standalone 2-track recorder without a USB
or FireWire port, plug the recorder’s digital output into the
digital input of your computer audio interface. If your interface lacks
a digital input, use analog out to analog in. Launch the recording
software. Set levels if necessary, start recording on your hard drive,
and play the 2-track recording containing your mixes. All the mixes
will copy in real time to your hard drive to create a single long wave
file.
If your 2-track recorder has a USB or FireWire port, plug it into your
computer’s matching port. The recorder will appear as a hard drive to
your computer. Copy the wave file(s) of the mixes to your computer hard
drive.
4. Now that all the song mixes are on your hard drive, you will convert
them to clips in an audio editing program. Start the software. If your
song mixes are in one long wave file, import the file to a single stereo
track. The waveform of the mixes appears. Zoom into the beginning
of the first song and play it. Using a mouse, mark the start and end
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Practical Recording Techniques
Figure 15.4
Highlighting a song to create a region or clip.
of the song to highlight it (Figure 15.4). Be sure not to include spaces,
noises, or outtakes on either side of the song. Save the highlighted
song as a clip or region. Repeat for the other songs.
If each song mix is a separate wave file, import the first song’s wave
file to a track. The waveform of the song appears as a clip or segment of
audio. Using a mouse, slip-edit or trim the beginning and end of the song
clip to remove extra space and noises. Repeat for the other songs.
It’s convenient to put each song clip on a different track, one after
another (Figure 15.5). That way you can easily adjust the spacing between
songs, and apply different processing to each song as needed.
5. Now that all the songs are in place and trimmed, add a fade-out at
the end of certain songs if desired. If you want to crossfade between
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Session Procedures, Editing, Mastering, and CD Burning
Figure 15.5
15
Placing song clips on successive tracks makes mastering easier.
two songs, overlap their clips near the transition point, and use the
crossfade function in your DAW.
6. Next you can adjust the spacing or gap between songs. Two to three
seconds of silence between songs is typical, but go by ear. Use a
longer space if you want to change moods between songs. Use a
shorter space to make similar songs flow together. A short space also
works well after a long fade-out because the fade-out itself acts like
a long pause between songs.
7. Click on and play part of each song’s waveform to check for loudness. Make all the songs equally loud by adjusting the track’s fader
before each song. If necessary, do a snapshot of each fader setting.
Here’s one method to match song levels. If most songs are equal in
level, set the fader to zero before each of those songs in order to avoid
processing. Then, insert a fader snapshot or fader-level envelope before
other songs: turn down any louder songs and turn up quieter songs to
match the rest of the songs. Do this by ear.
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Practical Recording Techniques
CAUTION: If you increase a song’s level, make sure the peaks
in the song don’t clip.
Another way to match song levels is to find the song with the highest
peaks, and leave its level alone Adjust the levels of other songs so they
match the loudness of the song with the highest peaks. Again, do this by
ear. You may need to turn up the intro of a song so it works in context
with the previous song. Also see www.har-bal.com.
8. Apply EQ to songs that need it. Put songs with different EQs on different tracks. If necessary, touch up levels after adding EQ.
9. If desired, apply multiband compression, limiting and normalization to the entire mix in order to get a “hot” or loud CD. Don’t
overdo it, or your project will be distorted and fatiguing to listen to.
Squashed dynamics can suck the life out of music. If you apply only
peak limiting and normalization, you’ll get a hot CD without altering the musical dynamics. Play CD track 40.
The idea is to knock down the peaks in the waveform because
they do not contribute to perceived loudness—the average level does.
Once you limit the peaks about 6 dB, you can normalize (raise the overall
level) and thus create a louder program. Normalizing to 100% of full scale
can create errors with some D/A converters, so you might normalize to
99%.
According to mastering engineer Bob Katz, hot CDs and quiet CDs
end up at the same level when processed with radio-station dynamic
processors. Overcompressed material does not sound louder on the air;
it sounds more distorted. So ignore the “loudness wars” and avoid excessive compression.
10. DAW software includes a feature called “Build mix to new soundfile,” “Export Audio,” or something similar. After your program is
edited, export (save) the mastered song mixes to a 16-bit/44.1 kHz
stereo wave file. If your recording was 24-bit, first turn on dithering.
That retains much of the 24-bit sound quality when converting to
16-bit format.
Transferring the Mastered Program to CD-R
To get your mastered songs onto a CD, you need professional CD burning
software that can insert song-start IDs within the single wave file of mas-
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Session Procedures, Editing, Mastering, and CD Burning
15
tered songs. The software can adjust the pause or gap length down to
zero, and can set the Start ID of each song anywhere in the program; that
is, it allows PQ subcode editing. Some programs that do this are Gear
Software Gear CD-RW and Gear Pro, Digidesign MasterList CD, Sony
Media Software CD Architect, Adaptec Jam, and Goldenhawk Technology CDRWIN.
I’ll describe CDRWIN as an example (www.goldenhawk.com). It
creates CD tracks from a single wave file by following a cue sheet: a text
file that lists the start time of each song. When the CD is recorded, the
software creates a Start ID for each song based on the cue sheet. With this
method you can create CD song-start IDs that occur even during a continuous program, such as a live concert recording. Here’s the procedure:
1. Note the start time of each song in the DAW editing software’s Edit
Decision List or playlist. Or check the start time of each song clip by
right-clicking on it or by looking at its beginning on the project time
line. The start time of each song is specified in your DAW in
minutes:seconds: frames, and there are 30 frames per second. Write
down the start time of each song.
2. In the cue sheet, make each song’s start time about one-third of a
second (10 frames) before the actual start time of each song. That
way the CD player’s laser has time to find the track before playing
audio. For example, if a song actually starts at 12:47:28, make its start
time in your cue sheet 12:47:18. The cue sheet should also include
the name and filepath of the mastered program’s wave file.
3. Place a blank CD-R in your CD burner. Do not put a paper label on
the CD before recording because the label can cause jitter.
4. Open your CD burning program and load in the cue sheet text file.
Set the recording speed to 2X to 4X speed to reduce errors. Some
CD-recorders and blank CD-Rs have fewer errors at higher speeds.
5. Start recording on CD. The CD-burning program writes the cuesheet start times in the CD-R’s table of contents, and copies the mastered program’s wave file to the CD-R as separate.cda (CD-audio)
tracks. Each track starts at the time you specified in your cue sheet.
To prevent glitches, do not multitask while the CD is burning.
6. When the CD is finished, handle it by its edges to prevent errorcausing fingerprints. Play the CD from start to finish to check for
glitches. Press the track-advance button to make sure each song
starts at the right time.
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Practical Recording Techniques
Another way to create master CDs is to use the Alesis MasterLink:
a CD recorder with a built-in hard drive and mastering tools. With it you
can record your stereo mixes, edit and master them, and burn a finished
CD. Sample rates can be up to 96 kHz and word length can be 16-, 20-, or
24-bit. The MasterLink includes sample-rate conversion and noise
shaping to alter sample rates and bit resolution as needed.
Several editing/mastering tools are offered with MasterLink, such
as 16 different playlists, gain control, editing start and end points, joining
or splitting song sections, EQ, compression, normalization, and peak
limiting.
If you’re intending the CD for commercial release, I recommend
using a professional CD checker such as the Clover QA1010 or EC-2. It
will catch unacceptably high error rates. Their Web site has a lot of useful
information on CD-Rs (www.cloversystems.com).
You can identify the CD either by writing on the label side with a
felt-tip marker or by sticking on a paper label. Special pens are available
to write on CDs without damaging the plastic. Use a label applicator
device and label design software such as Neato’s MediaFACE, Roxio EZ
CD Creator, or Stomp’s Click ‘N Design 3D. Some software can even print
liner notes, including the track numbers, titles, and timing. If you are
duplicating CDs yourself, you might want to use a CD printer rather than
labels.
Master Log
Type or print a log describing the CD-R master (such as shown in Table
15.2) and include it with your master.
Table 15.2
A CD Master Log
CD Master Log
Album title: Don’t Press That Button (demo)
Artist: Puff Daddy Bartlett
Mastering date: 2-26-06
Track
1
2
3
4
5
Start MM:SS:FF
Duration
00:00:00
03:24:20
06:41:00
09:32:05
12:29:11
03:23
03:15
02:49
02:55
03:07
Total running time: 15:47
362
Title
60 Gigabytes to Go
Unplugged Plug-In
Digital Dropout Blues
Late and See
Buffer the Vampire
Session Procedures, Editing, Mastering, and CD Burning
15
Also include the CD liner notes information such as song lyrics,
instrumentation, composers, credits, arrangers, publishers, and artwork.
Include contact information for the artist, engineer, and mastering engineer. Stay in contact with the duplication house, especially about artwork.
Before you send out the master, be sure to make another copy that
you keep in your studio. This copy can be used if the master is lost or
damaged.
Note that the master CD-R doesn’t leave the studio until all studio
time is paid for! When this is done, send the CD-R to the duplication
house.
The document “Recommendations for Delivery of Recorded Music
Projects” provides examples of session sheets, tracks sheets, and so on. It
also recommends media for delivering and backing up master recordings.
It can be found at http://www.aes.org/technical/documents/
AESTD1002.1.03–10_1.pdf.
It’s amazing how the long hours of work with lots of complex equipment have been concentrated into that little CD-R—but it’s been fun. You
crafted a product you can be proud of. When played, it recreates a
musical experience in the ears and mind of the listener—no small
achievement.
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16
THE MIDI STUDIO:
EQUIPMENT AND
RECORDING PROCEDURES
Welcome to the computerized world of MIDI equipment—samplers, synthesizers, sampling keyboards, drum machines, and sequencers. Because
other texts explain this equipment in detail, brief definitions serve the
purpose here. See Appendix D for books on MIDI.
Musical Instrument Digital Interface (MIDI) is a standard connection between electronic musical instruments and computers that allows
them to communicate with each other. Some of the things you can do
with MIDI are
• Make a keyboard, MIDI guitar, or breath controller produce a sound
like any instrument.
• Create the effect of a band playing. To do this, you record keyboard
performances into a computer memory, edit the recording note by
note if you wish, and have the recording play through synthesizers
and a drum machine in sync.
• Combine or layer the sounds of two electronic musical instruments
by playing them both with one keyboard.
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Practical Recording Techniques
• Automate a mixdown, or automate effects changes.
• Automate the playback of sound effects and music for video
productions.
The MIDI signal is a stream of digital data—not an audio signal—
running at 31,250 bits per second. It sends information about the notes
you play on a MIDI controller, such as a piano-style keyboard or drum
pads. Up to 16 channels of information can be sent on a single MIDI cable.
There are three types of MIDI ports on MIDI devices:
1. MIDI IN receives data going into the device.
2. MIDI OUT sends out data generated by the device.
3. MIDI THRU is like MIDI OUT, but duplicates the data that is at the
MIDI IN port.
Connect MIDI OUT from the sending device to MIDI IN of the
receiving device. For example, connect a keyboard controller’s MIDI OUT
to the MIDI IN connector of a sequencer or a sound module. Use MIDI
THRU to connect two or more receiving devices in a row. For example,
connect a keyboard controller’s MIDI OUT to sequencer MIDI IN, and
connect sequencer MIDI THRU to sound module MIDI IN.
MIDI-Studio Components
The following equipment typically is used in a MIDI studio:
•
•
•
•
•
•
•
•
•
•
•
•
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MIDI controller
Sequencer
Synthesizer
Sampler and sample CDs
Drum machine
Power amplifier and speakers
Personal computer
MIDI computer interface
Mixer
Recorder-mixer (optional)
2-track recorder
Effects
The Midi Studio: Equipment and Recording Procedures
16
• Audio cables
• MIDI cables
• Equipment stand
You have learned about most of these in previous chapters, but a
review might help at this point.
A MIDI controller is an instrument that generates MIDI data when
you play on it. Examples are a piano-style keyboard, drum pads, MIDI
guitar, or a MIDI breath controller. A synthesizer or drum machine can
act as a controller.
Some newer keyboard controllers are compact and lightweight, and
connect to your computer via a USB cable. Examples are Korg’s 37-key
microControl, M-Audio’s 25-key Oxygen 8, Edirol’s 49-key PC-300, and
Novation’s RemMote25 mini-synth. Because they have fewer keys than
a standard keyboard, they use octave up/down buttons.
A sequencer is a device or program that lets you record, edit, and
play back MIDI data. A recording done on a sequencer is called a
sequence, which is a MIDI song. Unlike an audio recorder, a sequencer
does not record audio. Instead, it records the key number of each note
you play, note-on signals, note-off signals, and other parameters such as
velocity, pitch-bend, and so on. A sequencer captures a performance, not
the sound. Then any sound you want can be played by that performance.
The recorded performance (sequence) can be modified to fix wrong notes,
etc.
A sequencer plays MIDI files (.mid files). They are sequencer recordings of your own performances, or are MIDI files that can be downloaded
from the Web.
The sequencer can be a standalone unit (Figure 16.1), a circuit built
into a keyboard instrument, or a computer running a sequencer program.
Like a multitrack audio recorder, a sequencer can record 8 or more tracks,
with each track containing a performance of a different instrument.
A synthesizer is a musical instrument that creates sounds electronically. It can play MIDI data, either from your MIDI controller, a MIDI
sequence, or a MIDI file downloaded from the Web. Synthesizers come
in four forms: piano-style, sound module, software, or a synth chip on a
sound card.
• A piano-style synth has a piano-style keyboard and built-in sound
generators (Figure 16.2). You might want to use more than one synth
to expand your palette of sounds.
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Practical Recording Techniques
Figure 16.1
A sequencer/drum machine.
• A sound module or tone module is a synthesizer without a keyboard. This standalone device is triggered by a sequencer or a
controller.
• A soft synth is a synthesizer that is simulated in software. It runs in
your CPU. The GUI of the software looks like a hardware synthesizer (Figure 16.2). A wavetable soft synth plays samples of real
instruments, which sound more realistic than an FM soft synth.
• Another option is a synth chip, which is built into many sound
cards.
A patch in a synthesizer is a sound preset (an instrumental timbre),
such as a synthesized piano, bass, or snare drum. A multitimbral synthesizer can play two or more patches at once. A polyphonic synthesizer
can play several notes at once (chords) with a single patch.
A sampler is a device that records sound events, or samples, into
computer memory and plays them back when activated by a sequencer
MIDI file or MIDI controller. A sample is a digital recording of one
note of a real sound source: a flute note, a bass pluck, a drum hit, etc. A
sample also can be a digital recording of a short segment of another
recording. The sampling process is described in Chapter 9 under “Digital
Recording.”
A soft sampler is software that plays samples and lets you map them
along your keyboard. Unlike a hardware sampler, a soft sampler has no
memory limit on the number of samples that are accessible. It lets you
import any sound, such as a wave file of a single note that you recorded,
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The Midi Studio: Equipment and Recording Procedures
Figure 16.2
16
A hardware-type synthesizer.
or a file from a sample CD. In contrast, a soft synth is limited to its supplied patches.
A soundfont is an audio sample (an instrument patch) in a
special.sf2 format. It’s like a wave file, but also includes a key range so
that when you play a MIDI note number (keyboard key), it plays the
sample pitch assigned to that note number. Soundfonts also include
velocity switching, note envelope, looping, release sample, filter, and lowfrequency oscillator (LFO) settings. A single soundfont can contain many
wave files of different pitches. You can import a soundfont into a sample
player. To use soundfonts, you need an EMU or SoundBlaster sound card,
a MIDI controller, MIDI interface, and MIDI sequencing software.
Often a sampler is built into a sample-playing keyboard, which
resembles an electronic piano. It contains samples of several different
musical instruments. When you play on the keyboard, the sample notes
are heard. The higher the key you press, the higher the pitch of the reproduced sample.
You can buy CDs with samples for use in your own projects. You
copy the samples to your hard drive, load them into a software sample
player, then trigger them with a sequencer or MIDI controller. For
example, TASCAM’s GigaStudio is sampling software with a huge
sample library. Other libraries are available from www.primesounds.com
and www.sonomic.com. Several DAW recording programs have samples
included.
You can also download samples from the Web. Two sources of piano
samples are Steinberg Grand VST 2.0 ($199 at www.steinberg.net) and
Maxim Digital Audio Piano (freeware at www.mda-vst.com). Some
samples on the Web come with their own sample-player software.
A drum machine is a device that plays built-in samples of all the
sounds of a drum set and percussion (Figure 16.1). It also is a sequencer
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Practical Recording Techniques
that records and plays back drum patterns played or programmed with
built-in keys or drum pads. Some units can sample sounds. Most
recorder-mixers have a drum machine built in.
A power amplifier and speakers (or powered speakers) let you hear
what you’re performing and recording. Usually these are small monitor
speakers set up in a Nearfield arrangement (about 3 feet apart and 3 feet
from you).
A computer is used mainly to run a sequencer program, which
replaces the standalone sequencer and its tiny LCD screen. The computer
monitor screen displays much more information at a glance, making
editing easier and more intuitive (Figure 16.3).
A step up from a sequencer program is a MIDI/digital audio recording program. It records both MIDI sequences and digital audio tracks on
your hard drive and keeps them in sync. In other words, this program
lets you add audio signals such as a vocal, sax, etc., to a MIDI sequence.
This software and your computer form a Digital Audio Workstation
(DAW). Details are given in Chapter 13 on Computer Recording.
Figure 16.3
370
Screen shot of a sequencer program.
The Midi Studio: Equipment and Recording Procedures
16
A film-sound program is a MIDI/digital audio program that
includes a window for viewing videos. It lets you enter a list of sound
effects or music with the time each occurs, and runs through the list automatically, triggering the effects and music at the right times, in sync with
the video.
A librarian program manipulates patches or samples and stores
them on computer disks. A voice editor program lets you create your
own patches. A notation program converts your performance to standard
musical notation. You can edit the notes, add lyrics and chords, and print
out a copy.
A MIDI computer interface plugs into a user port in your computer
and converts MIDI signals into computer data and vice versa. You need
this only if you’re using a computer in your system. Many sound cards
and audio interfaces include MIDI ports; others have a joystick port that
accepts MIDI when you add a joystick-to-MIDI cable.
If you have two or more synthesizers, or a synth and a drum
machine, you need a mixer to blend their audio outputs into a single
stereo signal.
A recorder-mixer (standalone DAW) combines a multitrack audio
recorder, MIDI sequencer, and mixer into a single chassis.
A 2-track recorder records the stereo mix of all your sound sources.
The recorder can DAT, MiniDisc, or hard drive.
Audio effects include compression, reverb, echo, gating, chorus, and
so on. MIDI effects are effects that process MIDI signals rather than audio
signals. Some MIDI effects are arpeggiate, transpose, and delay.
Audio cables carry audio signals and typically have a 1/4-inch
phone plug on each end. They connect synths, sound modules, and drum
machines to your mixer line inputs.
MIDI cables carry MIDI signals and are used to connect synths,
drum machines, and computers together so that they can communicate
with each other. A MIDI cable is a 2-conductor shielded cable with a 5pin DIN plug on each end. Pins 4 and 5 are the MIDI signal, pin 2 is
shield, and pins 1 and 3 are not connected.
An equipment stand is a system of tubes, rods, and platforms
that supports all your equipment in a convenient arrangement. It
allows comfort, shorter cable lengths, and more floor area for other
activities.
A keyboard workstation includes several MIDI components in one
chassis: a keyboard, a sample player, a sequencer, and perhaps a synthesizer, and disk drive. That’s everything you need to compose, perform,
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Practical Recording Techniques
and record instrumental music. Some workstations include drum sounds
so that you can get by without a separate drum machine.
MIDI Recording Procedures
The rest of this chapter describes recording procedures for several different MIDI studio setups, from simple to complex. The more complex
procedures are based on the simpler ones, so it helps to read all the procedures here. Also, read your instruction manuals thoroughly and simplify them into step-by-step procedures for various operations. Note that
each piece of MIDI gear has its own idiosyncrasies, and the instructions
may have errors or omissions. If you have questions, call or e-mail tech
support for your equipment.
2-Track Recording of a Synthesizer Performance
This is the simplest method of recording. You plug a MIDI interface into
your computer, plug your synth into the interface, and run a sequencer
program on the computer (Figure 16.4). An alternative to the computer
and sequencer program is a standalone sequencer. You play chords and
melody, record this MIDI data with your sequencer, and play back the
sequence through your synthesizer. The basic steps include:
1.
2.
3.
4.
5.
Select tempo, metronome, and MIDI track.
Assign a patch to the MIDI track.
Start recording.
Play a tune on your keyboard.
Play back the sequencer recording to hear it. Your performance will
be duplicated by the synthesizer.
Figure 16.4 A synthesizer connected via a MIDI interface to a computer
running a sequencer program.
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The Midi Studio: Equipment and Recording Procedures
6.
7.
8.
9.
10.
11.
12.
16
Quantize the track if desired.
Punch in/out to correct mistakes.
Edit the sequence recording.
Arrange the song by combining various sequences.
Enter any program changes (changes in timbre).
Play the composition and set recording levels.
Start the sequencer playing, and record the synth output on a 2-track
recorder. That recording is the final product.
Below are the details for each step.
Select Tempo, Metronome, and Sequencer Track
Choose a tempo in your sequencer. Set the metronome to count off
two measures. Select or click on the MIDI sequencer track you want to
record on.
Assign a Patch to the MIDI Track
Sounds are stored in banks, and each bank contains several different
patches (sounds), such as a fretless bass, grand piano, sax, drum set, and
so on. The patch is in your synthesizer, which is a standalone synth,
sound module, sound-card chip, soft synth, or soft sampler. Here’s how
to set up a MIDI track to play the desired patch:
1. If you are using a soft synth, insert it into an audio track.
2. Enable a MIDI track.
3. Set the input of the MIDI track to your MIDI interface device, omni
mode. This mode makes the track respond to all MIDI channels.
4. Set a unique MIDI channel for that track. For example, set MIDI
track 1 to channel 1.
5. Click on the output of the MIDI track. If you are using a soft synth,
select its name from the pop-up list. Then the track’s MIDI signal
will play the soft synth of your choice. If you are using a standalone
synth or sound module, select your MIDI interface device as the
output of the MIDI track. That way, the track’s MIDI signal will go
through the MIDI interface to your standalone synth, which will
play the patch for that track.
6. Choose a bank and patch. That is, choose the synth sound that you
want to play, such as a drum set or fretless bass. If necessary, set the
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Practical Recording Techniques
patch to channel 1 so that MIDI track 1 (which is also set to channel
1) will play the correct patch.
Start Recording
Using your mouse, click on the RECORD key on-screen or on your
computer keyboard. You’ll hear a metronome ticking at the tempo
you set.
Play Music on Your Keyboard
Listen to the sequencer’s metronome and play along with its beat. The
sequencer keeps track of the measures, beats, and pulses. As you play,
MIDI data from your keyboard goes from keyboard MIDI OUT to interface MIDI IN, and is recorded as a MIDI file or sequence. When the song
is done, click on STOP. The sequencer stops recording and should go to
the beginning of the sequence (the top of the tune).
Another way to record your performance is in step-time, one note
at a time. If the part is difficult to play rapidly, you also can set the
sequencer tempo very slow, record while playing the synth at that tempo,
and then play back the sequence at a faster tempo.
Play Back the Sequencer Recording
Click on PLAY. You’ll hear the sequence playing through your synthesizer. If you change the patch and click on PLAY, you’ll hear the same
performance played by a different instrument.
Quantize the Track
Quantizing is the process of automatically correcting the timing of each
note to the nearest note value (quarter note, eighth note, and so on). If
you wish, quantize the performance by the desired amount. Caution:
Quantizing can de-humanize the performance, making it too rhythmically perfect. It’s better to adjust the timing of certain notes only, and to
the smallest note value that works. Quantizing is essential if you want to
use a notation program.
Punch-In/Out to Correct Mistakes
To correct mistakes, you can punch-in to record mode before the mistake,
record a new performance, and then punch-out of record mode. Here’s
one way to do it:
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The Midi Studio: Equipment and Recording Procedures
16
1. Go to a point in the song a few bars before the mistake.
2. Just before you get to the mistake, punch-in to record mode and play
a new, correct performance.
3. As soon as you finish the correction, punch-out of record mode.
Alternatively, you can use autopunch. With this feature, the
computer punches in and out automatically at preset measures; all you
have to do is play the corrected musical part. Perform an autopunch as
follows:
1. Using the computer keyboard or mouse, set the punch-out point (the
measure, beat, and pulse where you want to go out of record mode).
2. Set the punch-in point (just before the part you want to correct).
3. Set the cue point (where you want the track to start playing before
the punch).
4. Click on PLAY.
5. When the screen indicates punch-in mode, or when the appropriate
measure comes up, play the corrected part.
6. The sequencer punches out automatically at the specified point in
the song.
These punch-in routines were done in real time. You can also punchin/out in step-time:
1. Go to a point in the song just before the mistake.
2. Set the sequencer to step-time mode.
3. Step through the sequence note by note, and punch-in to record
mode at the proper point.
4. Record the proper note in step-time.
5. Punch-out of record mode.
Edit the Sequence Recording
You might find it easier to edit the MIDI performance. Go to the MIDI
edit screen, which resembles a piano-roll. It’s a grid showing pitch verses
time. The pitch of each note is represented by its height on the grid, and
the duration of each note is represented by it length. You can grab incorrectly played notes and put them at the correct pitch and timing, delete
unwanted notes, copy and paste phrases of notes, and so on.
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Practical Recording Techniques
Arrange the Song by Combining Sequences
Now your sequenced performance is perfect, so you can put together
your composition. Many songs have repeated sections: The verse and
chorus are each repeated several times. If you wish, you can record the
verse and chorus once. Then copy the verse section and paste it every
place it occurs in the song. Do the same for the chorus.
You can rearrange song sections and append one section to another
by pressing a few keys on the computer. You can also have any section
repeated. In this way, you might build a song by having the computer
play sections A, A, B, A, C, A, B, B.
Enter Program Changes
To add variety to the song, you might want to have the synth play different programs (patches) at different parts of the song. For example, play
a piano on the first verse, organ on the second, and marimba on the
chorus. One way is to press different presets (program numbers) as you
record the sequence.
Another way is to record these program changes on another MIDI
track, which is called the controller track. Be sure to set the controller
track to the same channel as the performance track, and turn off any patch
on the controller track. Enter the appropriate program numbers at the
right time on your synthesizer. Putting the program changes on a separate track makes it easy to edit them. You can punch-in new program
changes just as you can punch-in new performances. When all the
program changes are correct, you can bounce or copy them to the performance track if you wish.
Some sequencers do not record the program settings on your synth.
They record only program changes. Consequently, when you play the
sequence into a synth you just turned on, you might hear the wrong
sounds. To prevent this problem, insert a few blank measures at the
beginning of the tune and record your initial program changes there,
according to the sounds you want to hear at the beginning of the tune.
To do this, follow the procedure below:
1. Insert two or four blank measures at the beginning of your
composition.
2. Set each track’s patch to the wrong program number. If you want
patch #17, for example, set it to #16. This way, you can key in a
program change later.
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16
The Midi Studio: Equipment and Recording Procedures
3. Set your sequencer to punch-in mode so that you record only on the
blank measures at the beginning of the tune.
4. When the punch-in starts, key in the correct program numbers. You
can perform these program changes in several passes, one track at
a time.
5. When the sequence plays back, it sets the synth automatically to the
correct patches at the beginning of the tune.
An alternative to this procedure is to record a system exclusive or
sysex dump—data about patch settings and so forth—into the sequencer.
This works only if your synth and sequencer implement the sysex dump.
Play the Composition and Set Recording Levels
If you’re using a standalone synth or sound module, plug its audio
output (mono or stereo) into the line inputs of your 2-track recorder. Hit
the PLAY key on your computer keyboard, and set the recording level for
your recorder to -3 dB maximum. Later, you can normalize the recording
(bring its level up to 0 dB maximum). If you’re working with a DAW, set
the track levels so that the level at the stereo mix bus reaches about -3 dB
maximum (in peak-reading meter mode).
Record the Synth Output
Once your levels are set, put your 2-track recorder in record mode, and
start the sequencer. In a DAW simply export the stereo mix to a wave file.
This produces the finished product: a stereo recording of your song.
Multitrack Recording of a Synthesizer Performance
With this method, you play the parts for several different instruments
(patches) on the same keyboard, and record each performance on a separate track of your sequencer software. During playback, the sequencer
plays the desired patches (instruments) in your synth. It sounds like a
band playing. You record the synthesizer’s output, or export the softsynth mix to a wave file, and that recording is the final product.
Each track and patch is set to a corresponding MIDI channel. For
example, suppose both track 1 and the bass patch are set to channel 1.
Then track 1’s performance in the sequencer plays the bass patch in the
synthesizer. Track 2 will play another patch (piano, flute, or whatever).
Some sequencers are designed so that, on power-up, track 1 goes to
channel 1, track 2 goes to channel 2, and so on. You simply select a track
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Practical Recording Techniques
to record on and select a patch for that track. The channel assignments
are already taken care of.
Here’s a short summary of the procedure. Record a drum part on
MIDI track 1. Then go back to the start of the sequence, play the drum
part, and add a bass line on track 2 in sync with the drums. Then go back
to the top and add a piano on track 3, and so on.
In the sequencer program, you set up a different patch (instrument
sound) on each MIDI track. Then you record a performance on each MIDI
track. Play back the multitrack recording through the synthesizer, which
plays all the patches simultaneously. Or you can use several synths, one
for each part, if necessary. Set each track to a different MIDI channel, and
if necessary set each instrument or patch to the same channel that its track
is set to.
Refer back to Figure 16.4 to see the connections. Here is an outline
of the steps for recording:
1.
2.
3.
4.
5.
6.
7.
8.
Start recording on the first sequencer track.
Play music on your keyboard.
Play back the recording.
Punch in/out or edit to correct mistakes.
Record overdubs on other tracks.
Edit the composition.
Mix the tracks.
Record the mix.
Again, these steps require a closer look. The following sections
present details for each one.
Record the First Sequencer Track
Adjust the metronome tempo and count-off on your sequencer as desired.
Select MIDI track 1. If necessary, set MIDI track 1 to MIDI channel 1.
Select the first patch you want to hear on your synthesizer (for
example, a drum set). If necessary, set the synthesizer patch to MIDI
channel 1. Click on RECORD on your computer screen.
Play Music on Your Keyboard
Listen to the sequencer’s metronome and play along with its beat, or
record in step-time. The sequencer keeps track of the measures, beats, and
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The Midi Studio: Equipment and Recording Procedures
16
pulses. When you click on STOP, the sequencer stops recording and goes
to the beginning of the sequence (the top of the tune).
Play Back the Recording
Click on PLAY on the computer screen. You’ll hear the sequence playing
through your synthesizer.
Punch-In/Out or Edit the Sequence to Correct Mistakes
As described in the previous section, you can correct mistakes by punching into record mode before the mistake, recording a new performance,
and then punching out of record mode. You might prefer to edit the
sequence instead. Also, you can quantize the track to make it rhythmically correct.
Record Overdubs on Other Tracks
With your first track recorded and corrected, you’re ready to record
other tracks. Select MIDI track 2. If necessary, set MIDI track 2 to MIDI
channel 2.
On your synthesizer, select the next patch or instrument timbre you
want to use (for example, bass). If necessary, set it to MIDI channel 2. You
might want to adjust the timbre of the patch with the parameter controls
on the synthesizer.
Then click on RECORD on your computer screen. Play the piano
keys on your keyboard while listening to the prerecorded drums on
track 1.
Repeat this procedure for other tracks and patches.
Edit the Composition
Now your sequenced performance is okay, so you can put together your
composition. As described in the previous section, you can rearrange
song sections and append one section to another by making selections on
your computer screen. You also can have any section replayed. Key in
program changes at the beginning of the song and anywhere else you
want the patch on a track to change.
Mix the Tracks
Now that your song is recorded and arranged, you’ll adjust the relative
volumes of the tracks to achieve a pleasing balance.
If your multitimbral synthesizer doesn’t have separate outputs for
each patch, you have to adjust the mix at the sequencer. To do this, adjust
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the volume (key-velocity scaling) of each track with your computer. This
only works if your keyboard is velocity-sensitive.
After you adjust the volume of each track in this way, click on PLAY
on your computer screen to play the sequence. The desired mix of patches
plays on your synth. Some synths let you add internal effects to the
overall mix.
If your synth has several individual outputs—one for each patch—
connect them to a mixer and set up a stereo mix with panning and
effects.
Record the Mix
If your synth has a single output (mono or stereo), use your 2-track
recorder to record the mix off that output. Plug your synthesizer’s audio
output into the line inputs of your 2-track recorder. Or, if your synth has
several individual outputs connected to a mixer, record off the mixer
stereo outputs.
Click PLAY on your computer screen and set the recording level for
your recorder. Then put your 2-track recorder in record mode and start
the sequencer. With a DAW, export the mix to a stereo wave file. This produces a stereo recording of your song.
Recording with a Keyboard Workstation
Each workstation operates in a different way, but here is a typical recording procedure:
1.
2.
3.
4.
5.
6.
7.
Set up for recording a song.
Record the first musical part.
Do step recording (optional).
Overdub more parts.
Punch-in.
Set effects.
Store the song.
The following sections present more detailed instructions for each
step.
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Set Up for Recording a Song
1. Press SEQ (for SEQUENCER) on the front panel.
2. A sequencer menu appears on the LCD screen. You can move a
cursor to select various parameters, and press the up or down
buttons to set the value of each parameter.
3. Set the time signature (in the Initialize menu).
4. Select the song number.
5. Set the tempo.
6. Select the track number (track 1 to start).
7. Select the program number for the desired sound (for example, a
drum set).
Record the First Musical Part
1. Press RECORD and START. Listen to two measures of metronome
clicks and then start playing.
2. When you finish, press STOP.
3. To hear what you just played, press START.
4. If you want to re-record the part, press REC and START, and play
the part again. You also could edit the performance, do punch-ins,
and so on.
Step Recording
Instead of performing a musical part in real time, you might prefer to
enter the notes one at a time, in step-time. Here’s the basic procedure:
1. Select the track number and the measure number where you want
to start.
2. Press RECORD and START.
3. Set the length of the first note (1/32 to 1/1).
4. If necessary, specify triplets, dotted notes, key dynamics, style of
playing, and rests.
5. Press the desired note or chords on the keyboard.
6. Release all the keys; the recording proceeds to the next step.
7. After entering all the notes, press STOP.
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Practical Recording Techniques
Overdub More Parts
1. To record the next track, set the track number to the desired track
(in this case, track 2).
2. Select the program number for the desired sound (for example, a
bass).
3. Press RECORD and START. As you listen to track 1 playing the drum
part, play a bass part on track 2.
4. Continue this procedure (steps 1 through 3), adding a new instrument each time.
Punch-In
You can correct mistakes easily in each track by punching in, either manually or automatically. The procedure follows:
1. Play the song to find the measures needing correction.
2. Select punch-in mode.
3. Page up one page, set the punch-in measure and the punch-out
measure, page down one page.
4. Set the measure number to a point a few bars before the punch-in.
5. Press RECORD and START. You’ll hear the song playing.
6. When the punch-in measure comes up, play the corrected part.
7. Press STOP when done.
Set Effects
You can go to the effects menus to set overall effects: hall reverb, chorus,
flanging, echo, distortion, and so on. Press the correct number on the
numeric keypad to get to the effects menus. (Note that these are built-in
keyboard effects, not outboard studio effects.)
Save the Song File
Save the completed song in multitrack form to a plug-in RAM card
or to an external sequencer and disk drive. To prevent data overload,
you might have to do the external sequencer recording one track at a
time with other tracks muted. If you’re satisfied with the final
results, record the stereo output signals of the workstation to a 2-track
recorder.
In addition to these basic operations, you can:
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16
• Bounce tracks (copy one track’s performance to another track so it
will play another patch)
• Edit each note event
• Create and copy patterns-for a drum or bass part, for example
• Modify track and song parameters
• Insert/delete/erase measures
• Modify sounds and effects (in great detail)
• Change the instrument (patch) that each track plays
Recording with a Drum Machine and Synth
This system combines a standalone synthesizer with a standalone drum
machine. Figure 16.5 shows how to connect the cables. The sequencer
shown in Figure 16.5 could be a computer with a MIDI interface running
a sequencer program.
Understanding Synchronization
The drum machine has a built-in sequencer that records what you tap on
its pads. Suppose you record a drum pattern with its built-in sequencer,
and you record a synthesizer melody with an external sequencer. How
do you synchronize the drum patterns in the drum machine with the synthesizer melody in the sequencer? In other words, how do you get the
two devices to play in sync when both have different patterns recorded
in different memories?
To synchronize the machines, you use a single MIDI clock (timing
reference) that sets a common tempo for all the equipment. The MIDI
Figure 16.5
machine.
Connections to make a sequencer drive a synth and drum
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Practical Recording Techniques
clock is a series of bytes in the MIDI data stream that conveys timing
information. The clock is like a conductor’s baton movements, keeping
all the performers in sync at the same tempo. The clock bytes are added
to the MIDI performance information in the MIDI signal. The clock signal
is 24, 48, or 96 pulses per quarter note (ppq). That is, for every quarter
note of the performance, 24 or more clock pulses (bytes) are sent in the
MIDI data stream.
Decide which device you want to be your master timing reference—
the sequencer or the drum machine. Set the master device to internal
clock and set the slave device to external clock or MIDI clock. Then the
slave will follow the tempo of the master.
To make this happen, the master sends clock pulses from its MIDI
OUT connector. The slave receives those clock pulses at its MIDI IN connector. The slave also passes clock pulses through its MIDI THRU connector to other slave devices down the chain.
If a slave device lacks a MIDI THRU, enable “Echo MIDI in” in the
slave device. Then the incoming pulses are duplicated at the MIDI OUT
connector.
In the setup shown in Figure 16.5, the sequencer’s clock drives both
the drum machine and the synthesizer. In other words, the sequencer is
the master tempo setter, and the drum machine and synth follow along.
The drum machine’s internally recorded patterns play in sync with the
synthesizer’s sequencer-recorded melody.
Basic Recording Procedure
Once you work out the synchronization problem, you are ready to begin
recording with this system. There are two basic methods. The first uses
the following steps:
1. Record drum patterns into the drum machine.
2. While listening to the drum patterns, record a synth part with your
sequencer.
3. Sync the drums and synth by setting MIDI clocks and channels.
4. Press the PLAY key on the sequencer.
Use these steps for the second method:
1. Record drum patterns into the drum machine.
2. Copy the MIDI sequence of those patterns onto one track of your
sequencer.
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The Midi Studio: Equipment and Recording Procedures
16
3. While listening to the drum track, record a synth part on another
track.
4. Play both sequencer tracks.
Here’s how to record drum patterns, then sync the drums with the
synth.
Recording Drum Patterns
Often the first step in composing a song is to record a drum pattern. There
are many ways to do this; the following is one suggested procedure:
1. On the drum machine, set the tempo, time signature, and pattern
length in measures. For this example, the pattern is 2 bars long.
2. Start recording, and play the hi-hat key in time with the metronome
beat.
3. At the end of 2 bars, the hi-hat pattern you tapped repeats over and
over (loops).
4. While this is happening, you can add a kick drum beat.
5. While the hi-hat and kick drum are looping, add a snare drum back
beat, and so on.
6. Mix the recording by adjusting the faders or keys on the drum
machine for each instrument.
Next, you repeat the process for a different rhythmic pattern—say,
a drum fill—and store this as Pattern 2. Then develop other patterns.
Finally, you make a song by repeating patterns and chaining them
together as described in the drum machine’s instruction manual. A song
is just a list of patterns in order.
It’s a good idea to add a count-off (a few measures of clicks) at the
beginning so that later overdubs can start at the correct time.
Some musicians like to program a simple repeating drum groove
first. While listening to this, they improvise a synth part. After recording
the synth part, they redo the drum part in detail, adding hand claps, tomtom fills, accents, and so on.
Synching Drums and Synth
Now you’re ready to add a synth part and synchronize it with the drum
track. The following procedure refers to a sequencer; it could also be a
computer running a sequencer program.
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Practical Recording Techniques
1.
2.
3.
4.
Record a synth part with the sequencer.
Set the drum machine to external clock or MIDI clock.
Set the sequencer to internal clock.
Set MIDI channels: set the drum machine to channel 1; set the
sequencer synth track and the synthesizer to channel 2. In this way,
the sequencer’s recorded performance will play only the synthesizer.
The MIDI clock still controls both devices, even though they are set
to different channels.
5. Press the PLAY key on the sequencer. As the sequencer plays its
recorded synth melody, the sequencer’s clock pulses drive the drum
machine and synthesizer at the same tempo. The drum machine
plays its internally recorded patterns while the synth plays the
sequencer track.
Another way to synchronize a drum machine and a synthesizer is
to record the drum patterns on one track of your sequencer. The advantage is whenever you rearrange parts of the music in the sequencer, you
also rearrange the drum part. So you don’t have to change drum patterns
each time you repeat or delete a verse or a chorus. Follow this procedure
to record the drum patterns into your sequencer:
1.
2.
3.
4.
Record a drum pattern with the drum machine’s internal sequencer.
Enable the drum machine’s clock out and MIDI data out.
On your sequencer, turn off the MIDI-THRU feature (if it has one).
Set the sequencer to external clock or MIDI clock mode, and set an
open track in record mode.
5. Hit the PLAY key on the drum machine. The sequencer records the
drum pattern on the open track.
To play back the drum patterns you just recorded, follow this
procedure:
1. Set the drum machine to external clock mode.
2. Set the sequencer to internal clock.
3. Set the drum machine’s track and the drum machine to the same
MIDI channel.
4. Load an empty pattern into the drum machine so that the machine
plays only the sequencer track.
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The Midi Studio: Equipment and Recording Procedures
16
5. Put the sequencer in play mode. The drum machine plays its
sequencer track at the sequencer’s tempo, and other synths connected to the sequencer play their tracks on their channels.
Recording with MIDI/Audio Recording Software
You can record MIDI sequences and digital audio tracks, edit them, and
mix them, all with your PC or Mac computer. You need MIDI/audio
recording software, an audio interface, and a MIDI interface. Many audio
interfaces (such as sound cards) have MIDI connectors built in.
The recording software has both MIDI tracks and audio tracks. The
MIDI tracks are recorded by a sequencer in the software, and the audio
tracks are recorded as wave files.
This DAW lets you add several tracks of vocals, sax, guitar, or any
audio signal to your MIDI sequences. While the recorded MIDI tracks
play, you overdub audio tracks, which are recorded to your hard drive.
Chapter 13 covers DAWs in detail.
Figures 16.6 and 16.7 show the system connections.
Several things happen when you play back what you recorded:
MIDI / AUDIO
RECORDING SOFTWARE
MIC
MIC PRE
OR MIXER
AUDIO/MIDI
INTERFACE
LINE IN
AUDIO
TRACKS OUT
TO MIXER IN
LINE OUT
MIDI IN
COMPUTER
MIDI OUT
MIDI OUT
SYNTH AUDIO
OUT TO MIXER IN
MIDI IN
SYNTHESIZER
Figure 16.6 Connections for a MIDI/audio recording system with a standalone
synthesizer (mixer not shown).
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Practical Recording Techniques
MIDI / AUDIO
RECORDING SOFTWARE
MIC
MIC PRE
OR MIXER
AUDIO/MIDI
INTERFACE
LINE IN
LINE OUT
AUDIO /
SOFT-SYNTH
MIX OUT
COMPUTER
MIDI IN
MIDI OUT
KEYBOARD MIDI CONTROLLER
Figure 16.7
Connections for a MIDI/audio recording system with a soft synth.
1. The sequencer’s MIDI signal comes from the MIDI OUT connector
in the audio/MIDI interface.
2. If you’re using an external synthesizer, sound module or drum
machine, that MIDI signal plays notes from those devices. If you’re
using a soft synth (virtual synth) in your computer software, the
MIDI sequence plays that soft synth.
3. If you’re using a soft synth, the digital audio tracks blend with the
audio from the soft synths, and this mix plays from the audio interface line output.
4. If you’re using an external standalone synthesizer, you feed its audio
output (and the audio-interface line output) into a mixer. You listen
to the mix over powered monitors, and record the mix on a 2-track
recorder.
5. If you’re using a soft synth, you export the digital audio/MIDI mix
to a stereo file on your hard drive.
Here is a typical procedure for using a MIDI/audio recording
system:
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The Midi Studio: Equipment and Recording Procedures
16
Record MIDI Tracks
1. Set up a MIDI track to record. Select the input device for the track.
Set the input channel to Omni so it will record any channel
from your MIDI controller. Repeat for all the tracks you want to
record.
2. Select an output device for the MIDI track from a drop-down
menu. If you want to play the track on an external sound module
or synth, set the output device to your MIDI interface. If you
want to play the track with a soft synth in the computer, such
as a GM General MIDI synth, specify which sound bank and patch
you want that track to play. Repeat for all the tracks you want to
record.
3. Set the output channel to Ch. 1 for track 1, Ch. 2 for track 2, and so
on. Set the tempo and time signature.
4. If you want an external sound module or synthesizer to play the
sounds, set it to the desired patch number so that you hear the
instrument you want to hear.
5. Start recording, and play the first MIDI part on your MIDI controller
or synth. If the part is difficult, you can record it at a slow tempo
and play it back at normal speed. Or record it in step-time. You can
edit wrong notes or chords. You could also enter the notes on a
musical scale, one at a time.
6. Repeat steps 1 through 3 for the other MIDI instruments.
Overdub Audio Tracks
1. Plug a mic into a mic preamp or mic input of a mixer. Connect
the preamp or mixer line output to your sound-card line input. Or
if you are using an outboard audio interface, connect its USB or
FireWire port to your computer. Select an audio track, and set its
input source to the audio interface channel that the mic signal is
plugged into.
2. Set the microphone input trim on your preamp or mixer, and set the
recording level in your recording software or its volume-controls
application.
3. Go to the beginning of the tune and hit PLAY in your DAW. The
MIDI sequences that you recorded earlier should start playing. (You
may need to press the PLAY key on a drum machine first if it is an
outboard device, rather than a part of software.)
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Practical Recording Techniques
4. While listening to the MIDI tracks playing through headphones,
record the vocal on an audio track. Then overdub more vocals and
non-MIDI instruments on other open tracks.
Edit and Mix
1. You might record a few takes of the vocal part and then cut and paste
selected portions to create a perfect take. For example, record one
good chorus and copy it in each chorus section in your song. You
also can edit individual MIDI notes or audio notes to correct their
pitch or timing.
2. After all your tracks are recorded, use the on-screen mixer to set up
a mix of the audio tracks and MIDI instruments. Adjust levels,
panning, and effects (plug-ins).
3. Play the song several times to perfect the mix and to set up
automation.
4. When you’re satisfied with the mix, export or save it as a stereo wave
file.
Refer to these chapters for more detail: Chapter 12, the sections on
mixing procedures and automation; Chapter 13, the sections on editing
and mastering.
Using Effects
No matter how you record with MIDI, effects are an important part of
the mix. To keep the sound lively, try to vary the effects throughout the
song, or use several types of effects at once.
For example, suppose you have a multitimbral synth, and you want
to add a different effect to each patch. Whether or not you can do this
depends on your synth. If it has a separate output for each patch, you
can use a different effect on each patch. But if your synth has only a single
output (mono or stereo) and you run it through an effects device, the
same effect is on all the patches.
If your song includes program changes (patch changes), you can
have the effects change when the patch changes. Set up a MIDI multieffects processor so that each synth program change corresponds to
the desired effect. When the synth program changes, the effect changes
also.
What if you want the effect, but not the synth patch, to change
during a mix? Reserve a track and channel just for effects program
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The Midi Studio: Equipment and Recording Procedures
16
changes. You don’t hear these program changes in your synth, but you
do hear the effects change. During a mixdown, it’s usually easier to
change effects automatically with your sequencer, rather than manually.
If your synth is a sampling keyboard, each sample could have reverberation or some other effect already on it; in that case each sample can
have a different effect. The effect is not recorded in the sequencer; rather,
the effect is part of the sampled sound. Note that the sampled reverberation cuts off every time you play a new note. Although this sounds
unnatural, you can use it for special effect.
Because effects are audio signals, audio recorders can record effects
but sequencers can’t. If an effect is an integral part of the sound of an
instrument, it’s probably best to record it with the instrument on the multitrack audio recorder. If the effect is overall ambience or reverb (to put
the band in a concert hall), however, then it’s best to add it to almost
everything during mixdown.
Some recording software lets you convert a MIDI track to an audio
track, then apply audio effects to that track. Other software uses a separate MIDI track and audio track for the same instrument patch. You apply
effects to the audio track.
MIDI effects (MFX) are nonaudio processes applied to MIDI signals,
such as an arpeggiator, echo/delay, chord analyzer, quantize, transpose
MIDI event filter, or velocity change. They can be used as real-time, nondestructive plug-ins in MIDI tracks.
Loop-based Recording
Let’s turn to a different aspect of computer recording. It’s possible to
compose, record, and perform music entirely in software. You might start
by creating a variety of loops or grooves, which are constantly repeated
rhythmic or musical patterns.
To make a loop in 4/4 time, use an editing program to trim the start
of the loop waveform just before beat 1, and trim the end of the loop after
beat 4, and just before the next beat 1. To avoid a click in the audio, the
trim points should be at zero crossings where the waveform crosses the
0-volt line.
There are four types of loop audio files based on their ability to have
their tempo changed:
• A loop made from a standard digital audio file. It has a fixed tempo,
so you must build your song around that tempo.
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Practical Recording Techniques
• A processed audio file. The tempo or pitch of the loop can be
changed by a time-stretch or pitch-shift algorithm in your audio
editing program. But if you need to change the tempo of a song, you
need to adjust all the loops you stretched.
• A file with REX-based time-stretching. The transients in the audio
file are cut into slices, whose spacing depends on the tempo. REX
files follow tempo changes in your composition.
• An acidized (RIFF) WAV file. Pitch and tempo information are in the
file header, and the audio is sliced at transients as with REX files.
Acidized files follow tempo and key changes. Slowing down the
loop can add artifacts, so it helps to start with a slow loop.
You drag and drop (or import) loops into audio editing programs.
There, you can copy and paste loops and play them along with audio and
MIDI tracks, such as soft-synth parts, vocals, and acoustic instruments.
Then add effects and do a mix.
You can also create loops externally, then import them into a DAW
recording program. For example, compose a repetitive beat of drums,
synth, and samples in a sampler/sequencer box. Record the beat onto a
CD, then use ripper software to convert the CD’s beat track to a wave
file. Import the wave file into a stereo track in your DAW. On other DAW
tracks, you might overdub vocals, doubled vocals, rap sections, and
harmony.
Some loop programs offer groove quantizing, which transfers the
timing and dynamics from one groove to another. It allows human-like
variations in timing and key velocity.
Loop libraries are collections of sampled drum and bass beats that
let you loop (repeat), change tempo, etc. The beats come in MIDI files
and wave files. Some examples are BitHeadz Phrazer, Club Tracks,
Beatboy, Fruity Loops, Keyfax Twiddly Bits, Vamtech Drumtrax, FXpansion Session Drummer, Discrete Drums, APO Multimedia Mix It,
Multiloops Naked Drums, Pocket Fuel RADS series, Smart Loops Percussion Kit, Ilio/Spectrasonics Groove Control and BackBeat, Wizoo VST
Drum Sessions, www.bigfishaudio.com, and Cakewalk loop libraries.
Complete looped rhythm tracks are available online for purchase. Just
add vocals.
Many DAW recording programs include loop-creation software,
which is also available separately. For example, Propellerhead Software
has a variety of programs to create and modify loops. They also offer soft
synths, drum machines, and sequencers. Here are some of their products:
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The Midi Studio: Equipment and Recording Procedures
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ReCycle starts with a loop and lets you change its tempo and pitch,
and replace and process sounds within the loop. By detecting peaks
in the waveform, ReCycle automatically breaks a loop into parts or
slices. A slice might be a snare-drum hit, a kick-drum hit, or a kickand-snare hit. When a loop’s tempo is changed, the start point of
each slice moves in time so that the beats occur at the right time.
(You might need to touch this up manually.) If the tempo is slowed
down, ReCycle creates a decay after each drum hit to fill in the gaps.
You can delete slices, change their length, attack, decay, and pitch,
and add compression or EQ. Then you can import the improved
loop as an REX2 file into an audio track in your sampler or sequencer
program. There you can control all aspects of the loop.
Reason is a group of synthesizers and samplers, a drum machine,
ReCycle-based loop player, mixer, effects, pattern sequencer, and
more (Figure 16.8). It’s all-in-one and easy to learn.
Figure 16.8
One screen in Reason software.
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Practical Recording Techniques
Reason Adapted is a lite version that is distributed as part of some
software bundles.
ReBirth is a software emulation of two analog bass-line synths and
two classic drum machines. Also included are delay, distortion, compression, and filtering. It integrates into sequencer software and
allows real-time audio streaming.
Reload is a utility that converts AKAI S1000 and S3000 formatted
media into formats (such as wave files) that can be used with
Reason, ReCycle, and other audio applications
ReWire is a useful feature found in some loop programs. It transfers or streams audio data between two computer applications in
real time, almost like a cable. This allows programs to communicate
with each other and synchronize together.
Other loop-based tools to compose and record music are listed
below.
Ableton Live lets you compose with soft synths, record hi-resolution
multitrack audio, and play loops in a live performance. With Live you
can create arrangements and modify grooves, timing, pitch, volume, and
effects.
Sony Media Software’s ACID products let you select audio loops
from Windows Explorer, drag them into a recording program’s track
view, and arrange them into multitrack projects. The tempo and key of
each loop are automatically matched to your project’s music in real time,
using the slicing technique described before. ACID uses time-stretching
algorithms to lengthen sounds when the tempo is slowed down. Prerecorded ACID loops are available.
Other loop-intensive DAWs include Image-Line Software FL Studio
(PC), Cakewalk Plasma (PC), and Apple GarageBand. Two great articles
on loops by Craig Anderton were in the July 2004 and August 2002 issues
of EQ Magazine.
“No Sound” MIDI Troubleshooting
Suppose you load a MIDI file and hit PLAY, but hear nothing. Or you
play notes on your MIDI controller, but there is no sound. Here are some
possible causes:
• Your computer is not communicating with your MIDI interface. Try
replugging the interface.
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• If you’re using a MIDI controller and MIDI sequencing software, the
MIDI sequencer track is not selected and Record-enabled.
• The MIDI sequencer track is on a different channel than the synth
or sound module.
• The MIDI sequencer track has no MIDI channel assigned.
• The MIDI sequencer track is assigned a channel already used by
another MIDI sequencer track.
• MIDI OUT or MIDI THRU is not connected to MIDI IN somewhere
in your system.
• The wrong sound bank was selected in a synth.
• The power amp, mixer, or synth output is off or turned down.
• The synth audio output is not connected to power amp.
• In the sequencer’s MIDI setup menu, your MIDI interface is not
selected as the input and/or output device.
• The sequencer track volume is not turned up.
• You started playing the file in the middle of a long note, rather than
at its beginning.
• The MIDI driver is buggy. Download the latest update from the
interface manufacturer.
Summary
MIDI is a computer code that transmits and stores information about the
position and motion of controls, such as keys on a piano-style keyboard.
In this way, MIDI lets you record and play back a musical performance
that is independent of the sound of that performance. Similarly, MIDI lets
you record and play back mixer-control settings, which allows for an
automated mixdown.
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ON-LOCATION RECORDING
OF POPULAR MUSIC
Sooner or later you’ll want to record a band—maybe your own—playing
in a club or concert hall. Many bands want to be recorded in concert
because they feel that’s when they play best. Your job is to capture that
performance on a recorder and bring it back alive.
There are several ways to record live:
• Record with two mics out front into a 2-track recorder.
• Using the PA mixer, record off a spare MAIN output.
• Using a recorder-mixer, record a stereo mic at the front of house
(FOH) position on tracks 1 and 2, while recording a feed from the
house mixer on tracks 3 and 4. Mix the tracks later.
• Feed the PA mixer INSERT jacks to a multitrack recorder.
• Feed the PA mixer INSERT jacks to a recording mixer, and from there
to a 2-track or multitrack recorder.
• Use a mic splitter on stage to feed the PA snake and recording snake.
Record to multitrack or 2-track.
We’ll start by explaining simple two-microphone techniques and
work our way up to elaborate multitrack setups.
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Practical Recording Techniques
Two Mics Out Front
Let’s start with the simplest, cheapest technique: two mics and a 2-track
recorder. The sound will be distant and muddy compared to using a mic
on each instrument and vocal. Not exactly CD quality! But you’ll hear
how your band sounds to an audience.
Recording this way is much simpler, faster, and cheaper than multimic, multitrack recording. Still, if time and budget permit, you’ll get
better sound with a more elaborate setup.
Equipment
Here’s what you need for 2-mic recording:
• A stereo mic, or two mics of the same model number. Your first
choice might be cardioid condenser mics. The cardioid pickup
pattern cuts down on room reverb and noise. The condenser type
generally sounds more natural than the dynamic type. Another
option is a pair of boundary mics such as PZMs. Simply tape them
to the ceiling several feet in front of your group.
• A 2-track recorder of your choice. Either use a unit with mic inputs,
or use a separate mic preamp.
• Blank recording medium. Bring enough to cover the duration of the
recording.
• Two long mic cables.
• Two mic stands.
• Headphones. You could monitor with speakers in a separate room,
but headphones are more portable and they sound the same in any
environment. Closed-cup headphones partly block out the live
sound of the band so you can better hear what’s going on tape.
Ideally you’d set up in a different room than the band is in, so you
can clearly hear what you’re recording.
Mic Placement
Use a pair of mic stands or hang the mics out of the reach of the audience. Aim the two mics at the group about 12 feet away, and space them
about 5 to 15 feet apart (Figure 17.1). Place the mics far apart (close to the
PA speakers) to make the vocals louder in the recording. Do the opposite
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On-Location Recording of Popular Music
Figure 17.1
17
Recording a musical group with two spaced microphones.
to make them quieter. The stereo imaging will be vague, but at least you
can control the balance between instruments and vocals.
To record a small folk group or acoustic jazz group, set up two mics
of the same model number in a stereo arrangement of your choice. Place
the mics about 3 to 10 feet from the group. The balance may not be the
best, but the method is simple.
Recording
After setting the recording level, leave it alone as much as possible. If you
must change the level, do so slowly and try to follow the dynamics of the
music.
If the playback sounds distorted—even though you did not exceed
a normal recording level—the mics probably overloaded the mic preamps
in the recorder. A mic preamp is a circuit that amplifies a weak mic signal
up to a useable level. With loud sound sources such as rock groups, a mic
can put out a signal strong enough to cause distortion in the mic preamp.
Some recorders have a pad or input attenuator. It reduces the mic
signal level before it reaches the preamp, and so prevents distortion. You
can build a pad (Figure 17.2), or buy some plug-in pads from your mic
dealer. Some condenser mics have a switchable internal pad that reduces
distortion in the mic itself. If you have to set your record-level knobs very
low (less than one-third of the way up) to get a 0 dB or 0 VU recording
level, that shows you probably need to use a pad.
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Practical Recording Techniques
Figure 17.2
Balanced and unbalanced microphone pads.
Recording from the Sound-Reinforcement
Mixer
You can get a fairly good recording by plugging into the main output of
the band’s sound-reinforcement mixer, also called the FOH or PA mixer.
Connect the main output(s) of the mixer to the line input(s) of a 2-track
recorder. Use the mixer output that is ahead of any graphic equalizer that
is used to correct the speakers’ frequency response (Figure 17.3).
Mixers with balanced +4 dBu outputs can produce a signal that is
too high in level for the recorder’s line input, causing distortion. This is
probably occurring if your record-level controls have to be set very low.
To reduce the output level of the mixer, turn it down so that its signal
peaks around -12 on the mixer meters, and turn up the PA power amplifier to compensate. That practice, however, degrades the mixer’s signalto-noise ratio.
A better solution is to make a 12-dB pad (Figure 17.4). The output
level of a balanced-output mixer is 12 dB higher than the normal input
level of a recorder with an unbalanced input.
Drawbacks
The recorded mix off the sound-reinforcement mixer might be poor. At
the FOH position, the sound mixer hears a combination of the band’s
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On-Location Recording of Popular Music
17
Figure 17.3
Recording from the sound-reinforcement mixer.
Figure 17.4
input.
A 12-dB pad for matching a balanced output to an unbalanced
amps and drums, the stage monitors, and the house speakers. The sound
mixer tries to get a good mix of all these elements. That means the signal
is mixed to augment the band’s on-stage instruments and vocals—not to
sound good by itself. A recording made from the FOH mixer is likely to
sound too strong in the vocals and too weak in the bass.
Recording with a 4-Tracker
A 4-track portable studio or recorder-mixer can do a good job of capturing a band’s live sound. With this method, you place a stereo mic (or a
pair of mics) by the FOH mixer. Record the mic on tracks 1 and 2 while
recording a spare FOH mixer output on tracks 3 and 4 (Figure 17.5). After
the concert, mix the four tracks together.
The FOH mics pick up the band as the audience hears it: lots of room
acoustics, lots of bass, but rather muddy or distant. The FOH mixer
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Practical Recording Techniques
Figure 17.5
Recording two mics and an FOH mix on a 4-track recorder-mixer.
output sounds close and clear, but typically is thin in the bass. When you
mix the FOH mics with the FOH-mixer signal, the combination has both
warmth and clarity.
Consider using a stereo mic at the FOH position. Good stereo mics
cost more than $500, but they provide great stereo in a portable, convenient package. You can also set up two mics of the same model number
in a stereo arrangement. For example, angle two cardioid mics 90 degrees
apart and space them 1 foot apart horizontally. Or place two omni mics
2 feet apart.
Plug the mics into your 4-track’s mic inputs 1 and 2. Adjust the trim
to prevent distortion, and set the recording level. Find a spare main
output on the FOH mixer, and plug it into your 4-track’s line inputs 3
and 4. You may need to use the 12-dB pad described earlier. Set recording levels and record the gig.
Back in your studio, mix the four tracks to stereo. Tracks 1 and 2
provide ambience and bass; tracks 3 and 4 provide definition and clarity.
You might hear an echo because the FOH mics pick up the band with
a delay (sound takes time to travel to the mics). A typical delay is 20 to
100 msec. To remove the echo, delay the FOH mix by the same amount.
Patch a delay unit into the insert jacks for tracks 3 and 4. As you adjust
the delay time up from zero, the echo will get shorter until the signals
are aligned in time. You may be surprised at the quality you get with this
simple method.
Recording Off the FOH Mixer Aux Output
On the FOH mixer, find an unused aux send output. Plug in a Y-cord:
One end goes into a PA mixer’s aux-send connector; the other end has
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On-Location Recording of Popular Music
Figure 17.6
17
Recording off the FOH mixer aux outputs.
two connectors that mate with your 2-track recorder’s line inputs (Figure
17.6). If you have two spare aux busses, you could plug a cable into both
of them, and set up a stereo mix.
Put on some good closed-cup headphones and plug them into your
2-track recorder to monitor the recording. Adjust the aux-send knob for
each instrument and vocal to create a good recording mix. Record the gig.
The advantages of this method are
• It’s simple. All you need is a recorder, a cable, and headphones.
• The recorded sound is close-up and clear.
• If the mix is done well, the sound quality can be very good.
The disadvantages are
• It’s hard to hear what you’re mixing. You may need to do several
trial recordings. Set up a mix, record, play back, and evaluate. Redo
the mix and try another recording.
• As you adjust the aux knobs, you might get in the way of the FOH
mixer operator.
• The recording will be dry (without effects or room ambience).
However, you could plug two room mics into the FOH mixer and
add them to the recording mix. Do not assign these mics to the FOH
output channels.
• If the aux send is pre-EQ, there will be no EQ on the mics. If the aux
send is post-EQ, there will be EQ on the mics, but it may not be
appropriate for recording.
Recording an aux mix works best where the setup is permanent and
you have time to experiment. Some examples are recording a church
service and recording a regularly scheduled show in a fixed venue.
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Practical Recording Techniques
Feeding the FOH Mixer Insert Sends to
a Multitrack Recorder
This is an easy way to record, and it offers excellent sound quality. Plug
one or more multitrack recorders into the insert-send jacks on the back
of the FOH mixer. Set recording levels with the FOH mixer input trims.
After the concert, mix the tracks back in your studio. The multitrack
recorder can be an MDM, hard-disk recorder, recorder-mixer, or multichannel audio interface plugged into a laptop computer.
Connections
Suppose you want to record one instrument or vocal on each track. In
each FOH mixer input channel locate the INSERT jacks. Connect that jack
to a recorder track input (Figure 17.7). INSERT jacks are usually pre-fader,
pre-EQ. So any fader or EQ changes that the FOH sound mixer does will
not show up on your recording.
If the FOH mixer has separate Send and Return INSERT jacks,
connect the Send to the recorder track input, and connect the recorder
track output to the Return. Some boards use a single stereo INSERT
jack with TRS (Tip/Ring/Sleeve) connections. Usually the tip is send
and the ring is return. In the stereo phone plug that you plug into
the INSERT jack, wire tip and ring together, and also to the cable hot
conductor.
On some FOH mixers with a TRS INSERT jack, you can use a mono
(tip/sleeve; TS) phone plug. Plug it in halfway to the first click so you
don’t break the signal path—the signal still goes through the FOH mixer.
If you plug in all the way to the second click, the signal does not go
through the FOH mixer—just to your multitrack recorder.
Figure 17.7
404
Feeding a multitrack recorder from the FOH mixer INSERT jacks.
On-Location Recording of Popular Music
17
What if you want to record several instruments on one track, such
as a drum mix? Assign all the drum mics to one or two output busses in
the FOH mixer. Plug the BUS OUT insert jack to the recorder track input.
Use two busses for stereo.
Monitor Mix
Although you can hear what you’re recording through the PA speakers,
you may want to set up a monitor mix over headphones. Here are two
ways to do this:
1. Connect all the multitrack recorder outputs to unused line inputs on
your mixer. Use those faders to set up a monitor mix. Assign them
to an unused bus, and monitor that bus with headphones.
2. Set up a monitor mix with some unused aux knobs. Monitor the aux
send bus over headphones.
Setting Levels
Set recording levels with the FOH mixer’s TRIM or INPUT ATTEN knobs.
This affects the levels in the house mix, so be sure to discuss your trim
adjustment in advance with the FOH mixer operator. If you turn down
an input trim, the FOH mixer operator must compensate by turning up
that channel’s fader and monitor send.
Set recording levels before the concert during the sound check (if
any!). It’s better to set the levels a little too low than too high, because
during mixdown you can reduce noise but not distortion. A suggested
starting level is -10 dBFS (decibel Full Scale), which allows for surprises.
Signals exceeding 0 dBFS will be distorted by digital clipping.
Keep a log as you record, noting the counter times of tunes, sonic
problems, and so on. Refer to this log when you mix.
Mixdown
After the recording is finished, mix down the tracks back in the studio,
spending as much time as you need to perfect the mix. You can even
overdub parts that were flubbed during the live performance, taking care
to match the overdubbed sound to the original recording.
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Practical Recording Techniques
Feeding the FOH Mixer’s Insert Sends to
a Recording Mixer
The previous method has a drawback: You have to adjust the FOH
mixer’s trim controls, and this changes the FOH mix slightly. A way
around this is to connect the FOH mixer’s direct outs or insert sends to
the line inputs of a separate recording mixer. Connect the recording mixer
insert sends to the multitrack recorder(s) (Figure 17.8). Set recording
levels with the recording mixer.
This method has some compromises. You need more cables and
another mixer. Also, the signal goes through more electronics, so it is not
quite as clean as connecting straight to the multitrack recorder.
Using the recording mixer’s faders, you can set up a monitor mix.
If you can hear the monitor mix well enough over headphones, you can
even omit the multitrack recorder, and attempt a live mix to 2-track.
In a live mix, never turn off a mic completely unless you know for
sure that it’s not going to be used. Otherwise, you’ll invariably miss cues.
Turn down unused mics about 10 dB.
Splitting the Microphones
With this method, you plug each mic into a microphone splitter on stage.
The mic splitter sends each mic’s signal to two paths: the FOH mixer
snake and the recording mixer snake. Some splitters have a third output
Figure 17.8
recorder.
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Connecting the FOH mixer to recording mixer to multitrack
On-Location Recording of Popular Music
17
to feed a stage monitor mixer. Back at the recording mixer where the
snake is plugged in, assign each mic to a different track.
In most mic splitters, the signals are transformer isolated to prevent
ground loops and interaction between the mixers. There is a ground-lift
switch on each channel (Figure 17.9). Set it to the position where you
monitor the least hum. Usually the mic-cable shields are grounded only
to one console, which provides phantom power. The cable shields going
to the other mixer are floated (disconnected) at the splitter with groundlift switches.
Multitrack Recording in a Van
Here’s the ultimate setup. Each mic is split three ways to feed the snake
boxes for the recording, reinforcement, and monitor consoles. A long multiconductor snake is run to a recording truck or van parked outside the
concert hall or club.
In the van, the snake connects to a mixing console, which is used to
submix groups of mics and route their signals to a multitrack recorder.
Figure 17.9
Transformer-isolated microphone splitter.
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Practical Recording Techniques
Sometimes two multitrack recorders are run in parallel to provide a
backup in case one fails.
Preparing for the Session
So far this chapter has given an overview of several on-location recording methods. The rest of this chapter explores the details of on-location
pre-session procedures.
Ready to record a live gig? The recording will go a lot smoother if
you plan what you’re going to do. So sit down, grab a pen, and make
some lists and diagrams as described here. We’ll go over the steps to plan
a recording.
Preproduction Meeting
Call or meet with the sound-reinforcement company and the production
company putting on the event. Find out the date of the event, location,
phone numbers, and e-mails of everyone involved; when the job starts;
when you can get into the hall; when the second set starts; and other pertinent information. Decide who will provide the split, which system
will be plugged in first, second, and so on. Draw block diagrams for the
audio system and communications (comm) system. Determine who will
provide the comm headphones.
If you’re using a mic splitter, work out the splitter feeds. The mixer
getting the direct side of the split provides phantom power for condenser
mics that are not powered on stage. If the house system has been in use
for a long time, give them the direct side of the split.
Overloud stage monitors can ruin a recording, so work with the
sound-reinforcement people toward a workable compromise. Ask them
to start with the monitors quiet because the musicians always want them
turned up louder.
Make copies of the meeting notes for all participants. Don’t leave
things unresolved. Know who is responsible for supplying what
equipment.
Figure 17.10 shows a typical equipment layout worked out at a preproduction meeting. There are three systems in use: sound reinforcement,
recording, and monitor mixing. The mic signals are split three ways to
feed these systems.
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On-Location Recording of Popular Music
Figure 17.10
17
Typical layout for recording a concert.
Site Survey
If possible, visit the recording site in advance and go through the following checklist:
• Check the AC power to make sure the voltage is adequate, the third
pin is grounded, and the waveform is clean.
• Listen for ambient noises: ice machines, coolers, 400-Hz generators,
heating pipes, air conditioning, nearby discos, etc. Try to have these
noise sources under control by the day of the concert.
• Sketch dimensions of all rooms related to the job. Estimate distances
for cable runs.
• Turn on the sound-reinforcement system to see if it functions okay
by itself (no hum, and so on). Turn the lighting on at various levels
with the sound system on. Listen for buzzes. Try to correct any
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Practical Recording Techniques
•
•
•
•
•
•
problem so that you don’t document bad sound-reinforcement
sound on your recording.
Determine locations for any audience/ambience mics. Keep them
away from air-conditioning ducts and noisy machinery.
Plan your cable runs from stage to recording mixer.
If you plan to hang mic cables, feel the supports for vibration. You
may need microphone shock mounts. If there’s a breeze in the room,
plan on taking windscreens.
Make a file on each recording venue including the dimensions and
the location of the circuit breakers.
Determine where the control room will be. Find out what surrounds
it—any noisy machinery?
Visit the site when a crowd is there to see where there may be traffic
problems.
Mic List
Now write down all the instruments and vocals in the band. If you want
to put several mics on the drum kit, list each drum that you want to mike.
As for keyboards, decide whether you want to record off each keyboard’s
output, or off the keyboard mixer (if any).
Next, write down the mic or direct box you want to use on each
instrument (see Table 17.1).
Make copies of this mic list. At the gig, you’ll place one list by the
stage box, and the other by each mixing console. The list will act as a
guide to keep things organized.
Track Sheet
Next, decide what will go on each track of your multitrack recorder. If
you have enough tracks, your job is easy: Just assign each instrument or
vocal to its own track: bass to track 1, kick to track 2, and so on.
What if you have more instruments than tracks? Suppose you have
an 8-track recorder, but you have 15 instruments and vocals (including
each part of the drum set). You’ll need to assign several instruments or
vocals to the same track. That is, you will set up a submix.
Let’s say the drum kit includes a snare, kick drum, two rack toms,
two floor toms, a hi-hat, and cymbals. If you want to mike everything
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On-Location Recording of Popular Music
17
Table 17.1 Mic List (Example)
Input
Instrument
Mic
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Bass
Kick
Snare
Hi-hat
Small rack tom
Large rack tom
Small floor tom
Large floor tom
Overhead L
Overhead R
Lead guitar
Rhythm guitar
Keyboard mixer
Lead vocal
Harmony vocal
DI
AKG D112
Shure Beta 57
Crown CM-700
Shure SM57
Shure SM57
Senn. MD421
Senn. MD421
AT 4051A
AT 4051A
Shure SM57
Shure SM57
DI
Beyer M88
Crown CM-311A
Table 17.2 Track Sheet (Example)
Track
Instrument
1
2
3
4
5
6
7
8
Drum mix L
Drum mix R
Bass
Lead guitar
Rhythm guitar
Keys mix
Lead vocal
Harmony vocal
individually, that’s nine mics. But you don’t need to use up nine tracks.
At the sound check, assign or group those mics to busses 1 and 2 to create
a stereo drum mix. Connect busses 1 and 2 to recorder tracks 1 and 2.
Control the overall level of the drum mix with submaster faders 1 and 2
(also called bus faders or group faders).
Use tracks 3 through 8 for amps and vocals (as shown in Table 17.2
below). Feed tracks 3 through 8 from insert sends.
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Practical Recording Techniques
Block Diagram
Now that your track assignments are planned, you can figure out what
equipment you’ll need. Draw a block diagram of your recording setup
from input to output (such as Figure 17.11). Include mics, mic cables, mic
stands and booms, DI boxes, insert cables, multitrack recorder(s), outlet
strip and extension cord, and recording media. You might bring your own
mixer and snake, or use those from the house system. On your diagram,
label the cable connectors on each end so you’ll know what kinds of
cables to bring. It’s a good idea to keep a file of system block diagrams
for various recording venues.
In Figure 17.11, the block diagram shows a typical recording method:
feeding FOH console insert jacks to a multitrack recorder. We’ll use this
example in the rest of this chapter.
Equipment List
Generate a list of recording equipment from your block diagram. Based
on Figure 17.11, you’d need the following recording gear:
Figure 17.11
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Example block diagram of recording setup.
On-Location Recording of Popular Music
17
• Direct boxes, mics, mic cables, mic stands, and booms (unless these
are part of the house system)
• Insert cables (for example, 8 stereo phone plugs to 8 RCA
connectors)
• Multitrack recorder
• Outlet strip and extension cord
• Recording medium (bring enough for the duration of the gig)
Don’t forget the incidentals: a cleaning tape, pen, notebook, flashlight, guitar picks, heavy-duty guitar cords, drum keys, spare tape,
mic pop filters, gaffer’s tape, guitar tuner, ear plugs, audio-connector
adapters, audio cable ground-lift adapters, in-line pads, in-line polarity
reversers, spare cables, gooseneck lights for the console, spare batteries,
water, food—and aspirin!
Bring a tool kit with screwdrivers, pliers, soldering iron and solder,
AC-outlet checkers, fuses, a pocket radio to listen for interference, ferrite
beads of various sizes for RFI suppression, canned air to shoot out dirt,
cotton swabs and pipe cleaners, and De-Oxit from Caig Labs to remove
oxide from connectors.
Check off each item on the list as you pack it. After the gig, you can
check the list to see whether you reclaimed all your gear.
Preparing for Easier Setup
You want to make your setup as fast and easy as possible. Here are some
tips to help this process.
Protective Cases
Mount your console and recorders in protective carrying cases. Install
casters or swivel wheels under racks and carrying cases so you can roll
them in. Rolling is so much easier than lifting and carrying. You might
permanently install the multitrack recorders in SKB carrying cases that
act as racks. When a remote job comes up, just grab them and go.
A very helpful item is a dolly or wheeled cart to transport heavy
equipment into the venue. Consider getting some lightweight tubular
carts. Being collapsible, they store easily in your car or truck. One maker
of equipment carts is Rock ‘n’ Roller, who advertises in the Musician’s
Friend catalog at www.musiciansfriend.com. Another cart is the Remin
Kart-a-Bag at www.kart-a-bag.com.
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Practical Recording Techniques
Pack mics, headphones, and other small pieces in cloth bags, trunks,
or milk crates.
CAUTION: Keep tapes and hard drives separated from
magnets, such as in headphones, monitor speakers, and
dynamic mics. (However, tape erasure is much less of a
problem with digital media such as DAT than it is with analog
tapes.)
You might want to build a mic container: a big box full of foam
rubber with cutouts for all the mics. Or construct a wheeled cabinet with
drawers for mics, DIs, and speaker cables.
In an article in the September-October 1985 issue of db magazine,
remote recording engineer Ron Streicher offers these suggestions:
Especially for international travel, make sure your documentation is up to date and matches the equipment you’re carrying.
Make a list of everything you take: all the details, such as each
pencil, razor blade, connector, etc. Also make sure your insurance
is up to date. You need insurance for en route as well as at the
destination.
I organize my cases so I know where every item is. They’re ready to
go anytime and make setup much faster. The cables are packed with
their associated equipment, not in a cables case. I check everything
coming and going, and try to have 100% redundancy, such as a small
mixer to substitute for the large console.
Mic Mounts
If you’ll be recording a singer/guitarist, take a short mic mount that
clamps onto the singer’s mic stand. Put the guitar mic in the mount. Also
bring some short mounts to clamp onto drum rims and guitar amps. By
using these mounts, you eliminate the weight and clutter of several mic
stands.
Some examples of short mounts are the Mic-Eze units by Ac-cetera
(www.ac-cetera.com). They have standard 5/8–27 threads and mic
clamps that either spring shut or are screw-tightened. Flex-Eze is two
clamps joined by a short gooseneck, Max-Eze is two clamps joined by a
rod, and Min-Eze is two clamps joined by a swivel.
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On-Location Recording of Popular Music
17
Snakes and Cables
You can store mic cables on a cable spool, available in the electrical
department of a hardware store. Wrap one mic cable around the spool,
plug it into the next cable and wrap it, etc. No more tangled cables!
A snake can be wrapped around a large reel or can be coiled in a
trunk. Commercial snake reels are made by such companies as Whirlwind, ProCo, and Hannay (www.hannay.com).
Use wire ties to join cables that you normally run together, such as
PA sends and returns.
Snake hookup is quicker if the snake has a multipin twist-lock
connector (such as Whirlwind W1 or W2). This connector plugs into a
mating connector that divides into several male XLRs. Those XLRs plug
into the mixing console. Leave the XLRs in the console carrying case.
You’ll find that the snake is easier to handle without the XLR pigtails on
it.
For a clean, rapid hookup of drum mics, put a small snake near the
drum kit, and run it to the main stage box. Or, put the main stage box by
the drum kit. Snakes are made by such companies as Whirlwind, ProCo,
and Horizon.
Check that all your mic cables are wired in the same polarity: pin 2
hot on both ends.
You might want to use 3-conductor shielded mic cables. Connect the
shield to ground only at the male XLR end. Also use cables with 100%
shielding. Those measures enhance the shielding capability of the shield
and reduce pickup of lighting buzzes.
In XLR-type cable connectors, do not wire pin 1 to the shell, or you
may get ground loops when the shell contacts a metallic surface.
Label all your cables on both ends according to what they plug into;
for example, DSP-9 effects in, track 12 out, power amp in, snake aux 2
out. Or you might prefer to number the cables near their connectors.
Cover these labels with clear heat-shrink tubing.
Label both ends of each mic cable with the cable length. Put a drop
of glue on each connector screw to temporarily lock it in place.
Rack Wiring
You can speed the console wiring by using a small snake between the
rack and the console, and between the multitrack recorders and the
console. When packing, plug the snakes into the rack gear and multi-
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Practical Recording Techniques
tracks, and coil the snake inside the rack and the multitrack carrying case.
In other words, have all your equipment pre-wired. At the gig, pull out
a bundled harness and plug it into the console jacks.
You might be feeding your multitrack from the insert jacks of the
house console. If so, use a snake with TRS stereo phone plugs at the
console end. Carry some TRS-to-dual-mono phone adapters to handle
consoles that have separate jacks for insert send and return.
Some engineers prefer to make a clearly marked interface panel on
the rear of the racks and plug into the panels. This is easier than trying
to find the right connectors on each piece of equipment.
Small bands might get by with all their equipment in a single, tall
rack. Mount a small mixer on top, wired to effects in the middle, with a
coiled snake and power cord on the bottom.
Small snakes for rack and multitrack connections are made by Hosa,
Horizon, and ProCo, among others.
Other Tips
Here are some more helpful hints for successful on-location recordings.
• Plan to use a talk-back mic from the board to the stage monitor
speakers during sound checks. You might bring a small instrument
amp for talkback so that you can always be heard.
• Hook up and use unfamiliar equipment before going on the road.
Don’t experiment on the job!
• Consider recording with redundant (double) systems so you have a
backup if one fails.
• Walkie-talkies are okay for pre-show use, but don’t use them during
the performance because they cause RF interference. Use hard-wired
communications headsets. Assistants can relay messages to and
from the stage crew while you’re mixing.
• During short set changes, use a laptop computer Local Area
Network to show what set changes and mic-layout changes are
coming up next; transmit this information to the monitor mixer and
sound-reinforcement mixer.
• Don’t put tapes or hard drives through airport X-ray machines
because the transformer in these machines is not always well
shielded. Have the tapes or hard drives inspected by hand.
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On-Location Recording of Popular Music
17
• Hand carry your mics on airplanes. Arrange to load and unload your
own freight containers, rather than trusting them to airline freight
loaders. Expect delays here and at security checkpoints.
• Get a public-liability insurance policy to protect yourself against
lawsuits.
• Call the venue and ask directions to the load-in door. Make sure that
someone will be there at setup time to let you in. Ask the custodian
not to lock the circuit-breaker box the day of the recording.
• A few days before the session, check out the parking situation.
• Just before you go, check out all your equipment to make sure it’s
working.
• Arrive several hours ahead of time for parking and setup. Expect
failures—there’s always something going wrong, something unexpected. Allow 50% more time for troubleshooting than you think
you’ll need. Have backup plans if equipment fails.
In general, plan everything in advance so you can relax at the gig
and have fun!
At the Session: Setup
Okay! You’ve arrived at the venue. After parking, offload your gear to a
holding area, rather than onstage, because gear on stage will likely need
to be moved.
Learn the names of the house sound-crew members, and be friendly.
These people can be your assets or your enemies. Think before you
comment to them! Try to remain in the background and do not interfere
with their normal way of doing things (for example, take the secondary
side of the split).
Power Distribution System
At the job, you need to take special precautions with power distribution,
interconnecting multiple sound systems, and electric guitar grounding.
Consider buying, renting, or making your own single-phase power
distribution system (distro). It will greatly reduce ground loops and
increase reliability. One source of AC power distribution equipment is
www.furmansound.com. Figure 17.12 shows a suggested AC power distribution system.
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Practical Recording Techniques
Figure 17.12
An AC power distribution system for a touring sound system.
The amp rating of the distro’s main breaker box should exceed the
current drain of all the equipment that will be plugged into the distro
system.
Power Source
If you’re using a remote truck, find a source of power that can handle the
truck’s power requirements, usually at a breaker panel. Some newer clubs
have separate breaker boxes for sound, lights, and a remote truck. Find
out whether you’ll need a union electrician to make those connections.
Label your breakers.
Check that your AC power source is not shared with lighting
dimmers or heavy machinery; these devices can cause noises or buzzes
in the audio.
The industry-standard power connector for high-current applications is the Cam-lok, a large cylindrical connector. Male and female
Cam-loks join together and lock when you twist the connector ring.
Distro systems and power cables with Cam-lok connectors can be rented
from rental houses for film, lighting, electrical equipment, or entertainment equipment. One such rental house is Mole-Richardson at
www.mole.com.
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On-Location Recording of Popular Music
17
Use an adapter from Cam-lok to bare wires. Pull the panel off the
breaker box, insert the bare wires, and connect the Cam-lok to your
truck’s power.
CAUTION: Have an electrician do the wiring if you don’t
know what you’re doing. A union electrician might be required
anyway. Some breaker boxes have Cam-loks already built in.
To reduce ground-loop problems, get on the same power that the
house sound system is using. From that point, run your distribution
system, or at least run one or two thick (14- or 16-gauge) extension cords,
to your recording system. These cords may need to be 100 to 200 feet long.
Plug AC outlet strips into the extension cord; then plug all your equipment into the outlet strips.
If your recording system is one or two multitrack recorders that will
connect to the FOH console, simply plug into the same outlet strip that
the FOH console is using.
Measure the AC line voltage. If the AC voltage varies widely, use a
line voltage regulator (power conditioner) for your recording equipment.
If the AC power is noisy, you might need a power isolation transformer.
Check AC power on stage with a circuit checker. Are grounded
outlets actually grounded? Is there low resistance to ground? Are the
outlets correct polarity? There should be a substantial voltage between
hot and ground, and no voltage between neutral and ground.
Some recording companies have a gasoline-powered generator
ready to use if the house power fails. If there are a lot of lighting and
dimmer racks at the gig, you might want to put the truck on a generator
to keep it isolated from the lighting power.
Interconnecting Multiple Sound Systems
If you encounter an unknown system where balanced audio cables are
grounded at both ends, you might want to use some cable ground-lift
adapters (Figure 17.13) to float (remove) the extra pin-1 ground connection at equipment inputs.
If you hear hum or buzz when the systems are connected, first make
sure that the signal source is clean. You might be hearing a broken snake
shield or an unused bass-guitar input.
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Practical Recording Techniques
Figure 17.13
A ground-lift adapter for balanced line-level cables.
If hum persists, experiment with flipping the ground-lift switches
on the splitter and on the direct boxes. On some jobs you need to lift
almost every ground. On others you need to tie all the grounds. The
correct ground-lift setting can change from day to day because of a
change in the lighting. Expect to do some trial-and-error adjustments.
If the house system has serious hum and buzz problems, offer help.
You can hear buzzes in your quiet truck that they can’t hear over the main
system with noise in the background.
Often, a radio station or video crew will take an audio feed from
your mixing console. In this case, you can prevent a hum problem by
using a console with transformer-isolated inputs and outputs. Or you can
use a 1 : 1 audio isolation transformer between the console and the feeds.
For best isolation, use a distribution amp with several transformerisolated feeds. Lift the cable shield at the input of the system you’re
feeding. Some excellent isolation transformers are made by Jensen
(www.jensen-transformers.com).
From the September/October 1989 db magazine, Guy Charbonneau,
owner of Le Mobile, Hollywood, has this to say:
The truck uses 3-phase, filtered 240 V power with a 25 kVA
transformer having six different taps. I don’t use the neutral; it
carries a lot of current from lighting systems. The truck chassis is
grounded. I use no ground lifts 99 percent of the time; I carry
through the shield with the sound company. In some clubs, I bring
50 amps to the stage on a 220 V line with a distribution box. All the
musicians’ instruments and the club console plug in there. This
prevents ground loops and AC line noises from coffee machines and
dishwashers. When working with a big P.A. company, I just ask for
their split. Often a Y-adapter works. Source: AES
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On-Location Recording of Popular Music
17
Connections
After unpacking, place one mic list by the stage box so you know what
to plug in where. Place a duplicate list by each console. Attach a strip of
white tape just below the mixer faders. Use this strip to write down the
instrument that each fader affects.
Based on the mic list you wrote, you might plug the bass DI into
snake input 1, plug the kick mic into snake input 2, and so on. Label fader
1 “BASS,” label fader 2 “KICK,” etc. Also plug in equipment cables
according to your block diagram.
Have an extra microphone and cable offstage ready to use if a mic
fails.
Don’t unplug mics plugged into phantom power because this will
make a popping noise in the sound-reinforcement system.
Running Cables
To reduce hum pickup and ground-loop problems associated with cable
connectors, try to use a single mic cable between each mic and its snakebox connector.
Avoid bundling mic cables, line-level cables, and power cables
together. If you must cross mic cables and power cables, do so at right
angles and space them vertically.
Plug each mic cable into the stage box; then run the cable out to the
each mic and plug it in. This leaves less of a mess at the stage box. Leave
the excess cable at each mic stand so you can move the mics. Don’t tape
the mic cables down until the musicians are settled.
It’s important that audience members do not trip over your cables.
In high-traffic areas, cover cables with rubber floor mats or cable
crossovers (metal ramps). At least tape them down with gaffer’s tape
pressed lengthwise onto the cables.
It helps to set up a closed-circuit TV camera and TV monitor to see
what’s happening on stage. You need to know when mics get moved accidentally, or when singers use the wrong mic, etc.
Recording-Console Setup
Here’s a suggested procedure for setting up the recording system
efficiently:
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Practical Recording Techniques
1. If the console is set up in a dressing room or locker room, add some
acoustic absorption to deaden the room reflections. You might bring
a carpet for the floor, plus acoustic foam or moving blankets for the
walls.
2. Turn up the recording monitor system and verify that it is clean.
3. Plug in one mic at a time and monitor it to check for hums and
buzzes. Troubleshooting is easier if you listen to each mic as you
connect it, rather than plugging them all in, and trying to find a hum
or buzz.
4. Check and clean up one system at a time: first the soundreinforcement system, then the stage-monitor system, then the
recording system. Again, this makes troubleshooting easier because
you have only one system to troubleshoot.
5. Use as many designation strips as you need for complex consoles.
Label the input faders bottom and top. Also label the monitor-mix
knobs and the meters.
6. Monitor the reverb returns (if any) and check for a clean signal.
7. Make a short test recording and listen to the playback.
8. Verify that left and right channels are correct, and that the pan-pot
action is not reversed audibly.
9. If you are setting up a separate recording monitor mix, do a preliminary pan-pot setup. Panning similar instruments to different
locations helps you identify them.
Mic Techniques
Usually the miking is left up to the sound-reinforcement company. But
there are some mic-related problems you should know about, such as
feedback, leakage, room acoustics, and noise. Here are some ways to
control these problems:
• Use directional microphones, such as cardioid, supercardioid, or
hypercardioid. These mics pick up less feedback, leakage, and noise
than omnidirectional mics at the same miking distance.
• With vocal mics, aim the null of the polar pattern at the floor monitors. The null (area of least pickup) of a cardioid is at the rear of the
mic—180 degrees off-axis. The null of a supercardioid is 125 degrees
off-axis; hypercardioid is 110 degrees.
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On-Location Recording of Popular Music
17
• Mike close. Place each mic within a few inches of its instrument. Ask
vocalists to sing with lips touching the mic’s foam pop filter.
• Use direct boxes. Bass guitar and electric guitar can be recorded
direct to eliminate leakage and noise in their signals. However, you
might prefer the sound of a miked guitar amp. You could record the
guitar direct from its effects boxes. Then use a guitar-amp emulator
during mixdown. Note that sequencers and some keyboards have
high-level outputs, so their DI boxes need transformers that can
handle line level.
• Use contact pickups. On acoustic guitar, acoustic bass, and violin,
you can avoid leakage by using a contact pickup. Such a pickup is
sensitive only to the instrument’s vibration, not so much to sound
waves. The sound of a pickup is not as natural as a microphone, but
a pickup may be your only choice. Consider using both a pickup
and a microphone on the instrument. Feed the pickup to the house
and monitor speakers, and feed the mic to the recording mixer.
• To reduce breath pops with vocal mics, be sure to use foam pop
filters. Allow a little spacing between the pop filter and the mic grille.
It also helps to switch in a low-cut filter (100-Hz highpass filter).
When you’re recording a band that has been on tour, should you use
their PA mics or your own mics? In general, go with their mics. The artists
and PA company have been using their mics for a while and may not
want to change anything. Most mics currently used in PA are good quality
anyway, unless they are dirty or defective.
If you’re not happy with their choice, you could add your own
instrument mics. Let the PA people listen to the sound in the recording
truck, or in headphones. If it sounds bad because of their mic choice, ask
“Would it be okay if we tried a different mic (or mic placement)?” Usually
it’s all right with them—it’s a team effort.
Electric Guitar Grounding
While setting up mics, you need to be aware of a safety issue with the
electric guitar. Electric-guitar players can receive a shock when they touch
their guitar and a mic simultaneously. This occurs when the guitar amp
is plugged into an electrical outlet on stage, and the mixing console (to
which the mics are grounded) is plugged into a separate outlet across the
room. If you’re not using a power distro, these two power points may be
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Practical Recording Techniques
at widely different ground voltages. So a current can flow between the
grounded mic housing and the grounded guitar strings.
CAUTION: Electric guitar shock is especially dangerous when
the guitar amp and the console are on different phases of the
AC mains.
It helps to power all instrument amps and audio gear from the same
AC distribution outlets. If you lack a power distro, run a heavy extension
cord from a stage outlet back to the mixing console (or vice versa). Plug
all the power-cord ground pins into grounded outlets. That way, you
prevent shocks and hum at the same time.
If you’re picking up the electric guitar direct, use a transformerisolated direct box and set the ground-lift switch to the minimum-hum
position.
Using a neon tester or voltmeter, measure the voltage between the
electric-guitar strings and the metal grille of the microphones. If there is
a voltage, flip the polarity switch on the amp. Use foam windscreens for
additional protection against shocks.
Audience Microphones
If you have enough mic inputs, you can use two audience mics to pick
up the room acoustics and audience sounds. This helps the recording to
sound “live.” Without audience mics, the recording may sound too dry,
as if it were done in a studio.
One easy method is to aim two cardioid mics at the audience. Put
them on tall mic stands, on the stage floor, on either side of the stage. If
those mic stands must not be seen, try hanging mics (Figure 17.14).
Some engineers pick up the audience and hall with two mics placed
at the FOH mix position. That’s an easy, effective way to capture the
crowd. But the signal from these mics is delayed relative to the on-stage
mics. If the FOH mix position is far from the stage (say, 50 feet or more),
this delay will cause an echo when the audience mics are mixed with the
stage mics. Prevent this by placing the audience mics fairly near the stage.
Or, during mixdown, delay the stage-mic signals so that they coincide
with the audience-mic signals. If you’re using the audience mics only to
capture applause, the delay is not an issue.
Here is another way to prevent this echo: Record the stage-mic mix
on two tracks of a DAW. Record the audience mics on two other tracks.
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On-Location Recording of Popular Music
17
SIDE VIEW OF MIC PLACEMENT
HANGING MICS
F.O.H. MICS
STAND
MICS
STAGE
Figure 17.14
AUDIENCE
Some audience miking techniques.
Slide the stage-mic tracks to the right in time (that is, delay them) so that
they coincide with the audience-mic tracks.
What if you don’t have enough tracks for the audience mics? Record
them on a 2-track recorder. Load this recording into your DAW along
with the stage-mic mix. Align the two recordings in time as described
above.
If the audience mics are run through the FOH mixer, leave the audience mics unassigned in that mixer to prevent feedback.
To get more isolation from the house speakers in the audience mics,
use several mics hung close to the audience. Some engineers put up four
audience mics maximum; some use eight to ten. Use directional mics and
aim the rear null at the house speakers.
Another option is not miking the audience, or not using the audience tracks. Instead, during mixdown, you could simulate an audience
with audience-reaction CDs. Simulate room reverb with an effects unit.
Setting Levels and Submixes
Now that the mics are set up, you might have time for a sound check.
That’s when you set recording levels. Have the band play a loud song.
Locate a mixer input module that is directly feeding a recorder track. Set
the input trim (mic preamp gain) to get the desired recording level on
each track. On a multitrack recorder, you might set each track’s level to
peak around -10 dB, which allows for surprises if someone plays louder
during the live gig.
Most of the mixer channels feed recorder tracks directly from the
insert sends. On those channels, any fader moves during the gig will not
affect the levels going onto the multitrack recorder. Why? In most mixers,
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Practical Recording Techniques
the insert send is pre-fader. That is, the signal at the insert send jack is
not affected by the fader. However, you may encounter FOH consoles
where some insert sends are tied up with signal processors. You must use
those channels’ direct-out jacks instead, which are usually post-fader
(unless they can be switched to pre-fader).
Now let’s set up the drum submix. (Ideally, you would do this with
the PA turned down, and monitor over headphones or Nearfield monitors in a separate room.) Assign each drum mic to busses 1 and 2, and
pan each mic as desired. Put the faders for busses 1 and 2 at design
center—the shaded area about one-half to three-quarters of the way up.
Set each drum-mic fader to about -10 dB. Set a rough drum-kit mix with
the input trims while keeping the mixer meters around 0 dB or 0 VU. Finetune the drum mix with the faders, and set the recording level with the
drum-mix bus faders.
Here’s another way to create the drum submix. Have the drummer
hit each drum repeatedly, one at a time, as you adjust the input trims to
prevent clipping. For example, ask the drummer to bang on the kick
drum. Turn down the kick drum’s input trim all the way. Slowly bring it
up until the clip LED (overload light) flashes. Then turn down the input
trim about 10 dB to allow some headroom.
When all the drum trims are set, set a drum mix with the faders, and
set the recording level with the bus 1 and 2 faders.
CAUTION: Any changes to the drum mix or drum-mix level
will show up on your recording.
Recording
If your recording will be synched later with a video tape, record a SMPTE
time-code feed on a spare track on each recorder.
A few minutes before the band starts playing, start recording. Keep
a close eye on recording levels. If a track is going into the red, slowly turn
down its input trim and note the recorder-counter time where this change
occurred.
CAUTION: If you are recording off the FOH mixer, turning
down its input trim will affect the house levels. The FOH mixer
operator will need to turn up the corresponding monitor send
and channel fader.
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On-Location Recording of Popular Music
17
This is a touchy situation that demands cooperation. Ideally, you set
enough headroom during the sound check so you won’t have to change
levels. But be sure the house mixer operator knows in advance that you
might need to make changes. Ask the operator whether she wants to
adjust the gain trims for you, so she can adjust corresponding levels at
the same time. Thank the operator for helping you get a good recording.
If you are recording with a splitter and mic preamps on stage, assign
someone to watch the levels and adjust them during the concert. Preamps
with meters allow more precise level setting than preamps with clip
LEDs.
Keep a track sheet and log as you record. For each song in the set
list, note the recorder-counter time when the song starts, or press the Set
Locate button on your multitrack recorder. Later, during mixdown, you
can go to those counter times or locate points to find songs you want to
mix. Also note where any level changes occurred so you can compensate
during mixdown. It helps to note a counter time when the signal level
was very high. When you mix the recording you can start at that point
in setting your overall mix levels.
Teardown
After the gig, pack your mics away first because they may be stolen or
damaged. Refer to your equipment list as you repack everything. Note
equipment failures and fix broken equipment as soon as possible.
After you haul your gear back to the studio, it’s time for mixing and
editing.
Some of the information this chapter was derived from two
workshops presented at the 79th convention of the Audio Engineering
Society in October 1985. These workshops were titled “On the Repeal
of Murphy’s Law-Interfacing Problem Solving, Planning, and General
Efficiency On-Location,” given by Paul Blakemore, Neil Muncy, and Skip
Pizzi and “Popular Music Recording Techniques,” given by Paul Blakemore, Dave Moulton, Neil Muncy, Skip Pizzi, and Curt Wittig.
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18
ON-LOCATION RECORDING
OF CLASSICAL MUSIC
Perhaps your civic orchestra or high school band is giving a concert, and
you would like to make a professional recording. Or maybe there’s an
organist or string quartet playing at the local college, and they want you
to record them.
This chapter explains how to make professional-quality recordings
of these ensembles. It describes the necessary equipment, microphone
techniques, and session procedures.
Incidentally, recording classical-music ensembles is a great way for
the beginning recording engineer to gain experience. With just two microphones and a 2-track recorder, much can be learned about acoustics,
microphone placement, level setting, and editing—all essential skills in
the studio.
Equipment
As a minimum, you need the following equipment to record classical
music on-location:
• 2-track recorder
• Microphones
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Practical Recording Techniques
•
•
•
•
•
Cables
Mic stands and stand adapters
Headphones (or powered speakers)
Mic preamps (optional)
Mixer (optional)
If you plan to record overseas, you may need a power converter that
converts 50 Hz, 220V AC power to 60 Hz, 110V. Or power your equipment
from batteries, and recharge the batteries overnight with a 220V/110V
converter. You also need some AC power outlet adapters.
The 2-Track Recorder
Two-track recordings can be made on MiniDisc, CD-R, portable hard
drive, laptop computer with a USB or FireWire port, DAT, or Flash
memory recorder. Make sure that your recording medium can handle the
length of the concert.
Microphones
Next on your list of equipment are some quality microphones. You need
two or three of the same model number, or a stereo mic. Good mics are
essential, for the microphones—and their placement—determine the
sound of your recording. You should spend at least $100 per microphone,
or rent some good ones, for professional-quality sound.
For classical-music recording, the preferred microphones are condenser types with a wide, flat frequency response and very low self-noise
(less than 21 dB equivalent SPL, A-weighted). (Self-noise is explained in
Chapter 6.)
These mics are available with an omni- or unidirectional pickup
pattern. An omnidirectional mic is equally sensitive to sounds arriving
from any direction, so it helps to add liveness (reverberation) to a recording made in an acoustically dead hall. Omni condenser mics have excellent low-frequency response, so they are a good choice for recording pipe
organ or bass drum.
A unidirectional microphone (such as a cardioid) is most sensitive
to sounds approaching the front of the microphone, and partly
rejects sounds approaching the sides and rear. It helps reduce excessive
reverberation in the recording. You need a pair of unidirectional mics
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On-Location Recording of Classical Music
18
if you want to do coincident or near-coincident stereo miking (see
Chapter 7).
Stands versus Hanging
You can mount the microphones on stands or hang them from the ceiling
with nylon fishing line. Stands are much easier to set up, but are more
visually distracting at live concerts. Stands are more suitable for recording rehearsals or sessions with no audience present.
The mic stands should have a tripod folding base and should extend
at least 14 feet high. You can purchase “baby booms” to extend the height
of regular mic stands. Many camera stores have telescoping photographic
stands that are lightweight and compact.
A useful accessory is a stereo bar or stereo microphone adapter. This
device mounts two microphones on a single stand for stereo recording.
Hiding Microphones
In some live concerts—especially those that are videotaped—the microphones must not be seen. You might be able to hang some miniature condenser mics, or place boundary mics on the stage floor. If the musical
ensemble is large (e.g., an orchestra), and you lay the mics on the stage
floor, this placement usually overemphasizes the front row of the ensemble and results in a muffled sound. But if the ensemble is small (e.g., a
string quartet or small choir), floor placement can work very well. You
can also mount boundary mics on the ceiling or on the front edge of a
balcony. These placements tend to sound too distant, but they may be
your only option.
Monitors
For monitoring you can use either high-quality loudspeakers or headphones. The headphones should be closed-cup, circumaural (around the
ear) types to block out the sound of the musicians. You want to hear only
what’s being recorded. Of course, the headphones should have a widerange, smooth response for accurate monitoring.
Loudspeakers give more accurate stereo imaging than headphones.
So you might want to set up monitor speakers in a control room separate
from the concert hall. Place a pair of Nearfield monitors about 3 feet apart
and 3 feet from you, on stands behind the mixer. An alternative is to use
high-end consumer or professional loudspeakers placed several feet from
the walls to weaken early reflections. You could add absorptive material
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Practical Recording Techniques
such as acoustic foam to the walls behind and to the side of the
speakers. For the best stereo imaging, sit exactly between the speakers,
and as far from them as they are spaced apart.
Mic Cables
You have to sit far from the musicians to clearly monitor what you’re
recording. To do that, you need a pair of 50-foot mic cables. Longer extensions are needed if the mics are hung from the ceiling, or if you want to
monitor in a separate room.
Mic Preamp or Mixer
You need a mixer when you want to record more than one source—
an orchestra and a choir, for instance, or a band and a soloist. You
might put a pair of microphones on the orchestra and another pair on
the choir. The mixer blends the signals of all four mics into a composite
stereo signal. It also lets you control the balance (relative loudness)
among microphones. You also need a mixer if you want to use spot
microphones or house microphones. Spot (accent) microphones are
placed close to each orchestra section or soloist. House microphones are
placed about 25 feet from the ensemble, back in the hall, to pick up hall
reverberation.
For the cleanest sound, consider using some high-quality, standalone mic preamps instead of the preamps built into recorders and
mixers. Place each preamp on stage; then run its line-level output signal
back to your recording gear.
Other miscellaneous equipment you may need includes a power
extension cord, an outlet strip, DAT dry cleaning tape, spare mic cables,
pen and notebook, and gaffer tape or vinyl mats to keep cables in place.
Stereo Microphone Techniques
As a starting point, you place two or three mics several feet in front of
the group, raised up high (Figure 18.1). The mic placement controls the
acoustic perspective or sense of distance to the ensemble, the balance
among instruments, and the stereo imaging.
Recall from Chapter 7 that there are four mic techniques commonly
used for stereo recording: coincident pair, near-coincident pair, spacedpair, and baffled omni techniques. Below is a review:
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On-Location Recording of Classical Music
18
MICS
SIDE VIEW
14' - 20'
4' - 20'
MUSICAL ENSEMBLE
Figure 18.1 Typical microphone placement for on-location recording of a
classical-music ensemble.
• Coincident-pair: Two directional mics angled apart with their grilles
nearly touching and their diaphragms aligned vertically.
• Near-coincident pair: Two directional mics angled apart and spaced
a few inches apart horizontally.
• Spaced pair: Two or three matched microphones of any pattern
aiming straight ahead toward the ensemble and spaced several feet
apart horizontally.
• Baffled omni: Two omnidirectional mics that are ear spaced and separated by a padded baffle or a hard-surface sphere.
Recall from Chapter 6 that boundary microphones can be mounted
on clear plastic panels about 2 feet square. You can space these panels
apart for spaced-pair stereo, or place them with one edge touching to
form a “V.” Aim the point of the V at the ensemble. This near-coincident
arrangement provides excellent stereo imaging. Also available is a stereo
boundary microphone that is smaller than the two panels and provides
excellent stereo imaging, extended low-frequency response, and mono
compatibility.
Preparing for the Session
Once you have the equipment, you are ready to go on location. First, ask
the musical director what groups and soloists will be playing, where they
will be located, and how long the program is.
If possible, plan to record in a venue with good acoustics. It should
have low background noise and adequate reverberation time for the
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Practical Recording Techniques
music being performed (typically 1.5 to 2 seconds). This is very important, because it can make the difference between an amateur-sounding
recording and a commercial-sounding one. Try to record in an auditorium or spacious church rather than in a band room or gymnasium. If
you’re forced to record in a hall that is relatively dead, you might want
to add artificial reverberation to the recording back in the studio.
Next, get all your equipment ready. If you’re recording to DAT, fastforward and rewind the blank DAT tape and clean the heads with a dry
cleaning tape. Label the recording medium with the name of the artist,
location, and date of the session. Check all cables and equipment for
proper operation.
Keep your equipment inside your home or studio until you’re ready
to leave. A recorder left outside in a cold car may become sluggish if the
lubricant stiffens, and batteries may lose some voltage.
Session Setup
Allow an extra hour or so for setup and for fixing broken cables, etc.
There’s always something unexpected in any new recording situation.
When you first arrive at the recording venue, locate some AC power
outlets where you want to set up. Check that these outlets are “live.” If
not, ask the custodian to turn on the appropriate circuit breaker. Always
check in with union technicians if the session is at a union venue.
Find a table or folding chairs on which to set your equipment. You
might even sit in an audience seat with a portable recorder on your lap.
Plug into the AC outlets and let your equipment warm up. Leave a few
turns of AC cord near the outlet, and tape down the cord so that it isn’t
pulled out accidentally.
Then take out your microphones and place them in the desired
stereo miking arrangement. As an example, suppose you are recording
an orchestra rehearsal with two crossed cardioids on a stereo bar (the
near-coincident method). Screw the stereo bar onto a mic stand, and
mount two cardioid microphones on the stereo bar. For starters, angle
them 110 degrees apart and space them 7 inches apart horizontally. Aim
them down so that they point at the orchestra when raised.
You may want to mount the microphones in shock mounts or put
the stands on sponges to isolate the mics from floor vibration.
As a starting position, place the mic stand behind the conductor’s
podium, about 12 feet in front of the front-row musicians. Connect mic
cables. Raise the microphones about 14 feet off the floor. This prevents
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On-Location Recording of Classical Music
18
overly loud pickup of the front row relative to the back row of the
orchestra.
Mic techniques for piano recitals and other solo instruments are
covered in Chapter 8.
Leave some extra turns of mic cable at the base of each stand so you
can reposition the stands. This slack also allows for people pulling on the
cables accidentally. Try to route the mic cables where they won’t be
stepped on, or cover them with mats.
Make connections in one of the following ways:
• If you are using two mics, and your recorder has high-quality mic
preamps, plug the mics directly into the recorder mic inputs.
• If you prefer to use an outboard mic preamp, plug the mics into the
preamp, and plug the preamp output into the recorder line inputs.
• If you’re using multiple mics and a mixer, plug the mics into the
mixer mic inputs, and plug the mixer stereo outputs into the
recorder line inputs.
Now put on your headphones, turn up the recording-level controls,
and monitor the signal. When the orchestra starts to play, set the recording levels to peak around - 12 dBFS (decibels Full Scale).
Microphone Placement
Nothing has more effect on the production style of a classical-music
recording than microphone placement. Miking distance, stereo positioning, and spot miking all influence the recorded sound character.
Distance
The microphones must be placed closer to the musicians than a good live
listening position would be. If you place the mics out in the audience
where the live sound is good, the recording probably will sound muddy
and distant when played over speakers. That’s because the recorded
reverberation is condensed into the space between the playback speakers, along with the direct sound of the orchestra. Close miking (5 to 20
feet from the front row of the ensemble) compensates for this effect by
increasing the ratio of direct sound to reverberant sound.
The closer the mics are to the orchestra, the closer it sounds in the
recording. If the instruments sound too close, too edgy, too detailed—if
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Practical Recording Techniques
the recording lacks hall ambience—the mics are too close to the ensemble. Move the mic stand 1 or 2 feet farther from the orchestra and listen
again.
If the orchestra sounds too distant, muddy, or reverberant, the mics
are too far from the ensemble. Move the mic stand a little closer to the
musicians and listen again.
Eventually you’ll find a “sweet spot” where the direct sound of the
orchestra is in a pleasing balance with the ambience of the concert hall.
Then the reproduced orchestra will sound neither too close nor too far.
Another way to vary the direct/reverb ratio is to mix the main pair
of mics with distant house mics. Place the main pair just behind the conductor. Mix in a second pair of house mics placed about 23 to 52 feet
behind the main pair. The house mics are cardioids aiming at the upper
rear corners of the hall to pick up reverb, spaced about 12 feet apart and
about 30 feet above the floor. Even a small amount of house mics in the
mix will increase the sense of distance of the orchestra. Adjusting the
direct/reverb ratio is best done back in the control room during
mixdown.
Stereo-Spread Control
Now concentrate on the stereo spread. If the spread heard over headphones is too narrow, that means the mics are angled or spaced too close
together. Increase the angle or spacing between mics until localization is
accurate. Angling the mics farther apart makes the instruments sound
farther away; spacing the mics farther apart does not, but may make the
images less focused.
If the instruments that are slightly off-center are heard far-left or farright in your headphones, your mics are angled or spaced too far apart.
Move them closer together until localization is accurate.
You localize sounds differently with headphones than with speakers. For this reason, coincident-pair recordings have less stereo spread
over headphones than over loudspeakers. Take this into account when
monitoring.
You can test the stereo localization accuracy of your chosen stereo
miking method. If you have time, record yourself speaking from various
positions on stage while announcing your position: far-left, half-left,
center, half-right, and far-right. Listen to the monitor system to check
whether the image of your voice is reproduced in corresponding posi-
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On-Location Recording of Classical Music
18
tions. Generally, the far-left and far-right positions should be reproduced
at the left and right loudspeakers, respectively.
Soloist Pickup and Spot Microphones
Sometimes a soloist plays in front of the orchestra. By raising or lowering the stereo mic pair, you can control the balance between soloist and
ensemble. If the soloist is too loud relative to the orchestra (as monitored),
raise the mics. If the soloist is too quiet, lower the mics. You may want
to add a spot mic about 3 feet from the soloist and mix it with the other
microphones.
Many recording companies prefer to use several spot mics and a
multitrack recorder when taping classical music. Such a method gives
more control of balance and definition and is necessary in many situations. If you use spot or accent mics on various instruments or instrumental sections, mix them at a low level relative to the main pair—just
loud enough to add definition, but not loud enough to destroy depth.
Operate the spot-mic faders subtly or leave them untouched. Otherwise
the close-miked instruments may “jump forward” when you bring up the
fader, and then “fall back in” when you bring down the fader.
Spot mics sound more natural if you delay their signals according
to this formula:
Delay in seconds = 1.25 ¥ Miking distance in feet/1130 feet per second.
For example, if the main stereo mics are 12 feet from the ensemble,
the spot-mic delay should be about 1.25 ¥ 12/1130 = 13 milliseconds.
Solo the main stereo pair, and note the image locations of instruments that you are spot-miking. Pan the spot mics so their image locations coincide with those of the main mic pair.
Recording
Now that the mics are positioned properly, you’re ready to record.
At a live concert, you might want to set your recording levels to read
about -15 dBFS with the opening applause. This procedure should
result in approximately correct recording levels when the musicians
start playing. Or set the record-level controls where they were at previous sessions.
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Practical Recording Techniques
Start recording a few seconds before the music starts. Once the
recording is in progress, let the recording-level meters peak at -3 dB
maximum. This allows a little headroom for surprises. Leave the recording level alone as much as possible. If you must adjust the level, do so
slowly and try to follow the dynamics of the music.
If there is applause at the end of a musical piece, you can fade it out
over 3 to 5 seconds by slowly turning down the recording-level controls
or the mixer master volume control. Or leave it alone and do the fadeout while editing the program.
Most classical recording sessions are done in several takes. Write
down the recorder counter times for these takes, and slate each one. Mark
the keeper takes for later editing.
After the concert, pack the mics away first; otherwise, they may be
stolen or damaged.
Editing
Once you have your tapes home, you may want to edit them to make a
tight presentation. Editing is done with a Digital Audio Workstation
(DAW), as described in Chapter 13.
Put about 3 or 4 seconds of silence between each selection. Or you
may want to insert an interval of recorded “room sound” (“room tone”)
especially between movements of a symphony.
Some on-location recordings have a fair amount of background
noise. If you insert silence between pieces, there will be an abrupt cutoff
of this noise at the end of each piece. To prevent that, either fade the noise
down to silence, or replace the silence with room tone.
If you recorded a live concert with applause, fade down the applause
over several seconds. At the point where the applause fades to silence,
edit that to a point a few seconds before the start of the next piece, and
fade up there.
Note the start time of each piece. Finally, launch your CD burning
software and enter Start IDs as described in Chapter 15.
Congratulations! You now have your finished product: a realistic,
professional recording of a classical-music ensemble.
438
19
SURROUND SOUND:
TECHNIQUES AND MEDIA
So far we’ve covered techniques that result in a 2-channel stereo recording. With stereo, you hear all the instruments and reverb in front of you,
in the area between the two loudspeakers. But with surround sound, you
hear audio images in every direction. For example, the musical ensemble
could be up front, while the hall ambience envelops you from the sides
and rear.
Stereo uses two channels feeding two loudspeakers in front of you.
Surround sound uses multiple channels feeding multiple speakers placed
all around you. A disadvantage of stereo is that you must sit in a tiny
“sweet spot” to hear correct localization. In contrast, surround sound can
be heard correctly in a wide area between the speakers.
Surround gives a wonderfully spacious effect. It puts you inside the
concert hall with the musicians. You and the music occupy the same
space—you’re part of the performance. For this reason, surround is more
musically involving, more emotionally intense, than regular stereo.
There’s a sense of envelopment. Surround mixing is fast becoming a valuable new tool to offer your customers. Because many listeners have home
theater systems with multiple speakers, they are already set up to play
surround audio recordings.
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Practical Recording Techniques
A magazine devoted to multichannel sound production is Surround
Professional found at www.surroundpro.com.
Surround Speaker Arrangement
Inherited from the film industry, surround sound uses six channels
feeding six speakers placed around the listener. This forms a 5.1 surround
system, where the “point 1” is the subwoofer or low-frequency effects
(LFE) channel. The LFE channel is band-limited to 125 Hz and below,
while the other channels are full bandwidth (20 Hz to 20 kHz). “5.1” is a
channel format—a surround-sound standard that states the number of
channels, their frequency response, and the speaker placement.
The six speakers are:
•
•
•
•
•
•
Left-front
Center
Right-front
Left-surround
Right-surround
Subwoofer
Figure 19.1 shows the recommended placement of monitor speakers
for 5.1 surround sound. It is the standard setup proposed by the International Telecommunication Union (ITU). From the center speaker, the
left and right speakers should be placed at ±30 degrees, and the surrounds at ±110 degrees. (Some engineers prefer 120 to 125 degrees for the
surround speakers.) If you are mixing movie soundtracks, use dipole
speakers for the surrounds, and place them to the sides (±90 degrees).
The left-front and right-front speakers provide regular stereo. The
surrounds provide a sense of envelopment due to room ambience. They
also allow sound images to appear behind the listener. Deep bass is filled
in by the subwoofer. Because we do not localize low frequencies below
about 120 Hz, the sub can be placed almost anywhere without degrading
localization.
Originally developed for theaters, the center-channel speaker is
mounted directly in front of the listener. In a home-theater system, it is
placed just above the TV screen, or just below and in front of the TV
screen. This speaker plays center-channel information in mono, such as
dialog.
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Surround Sound: Techniques and Media
Figure 19.1
sound.
19
Recommended placement of monitor speakers for 5.1 surround
Why use a center speaker, when two stereo speakers create a
phantom center image? If you use only two speakers and you sit offcenter, the phantom image shifts toward the side on which you’re sitting.
But a center-channel speaker produces a real image, which does not shift
as you move around the listening area. The center speaker keeps the
actors’ dialog on-screen, regardless of where the listener sits.
Also, the phantom center image does not have a flat frequency
response, but a center speaker does. Why is this? Remember that a center
image results when you feed identical signals to both stereo speakers. The
right-speaker signal reaches your right ear, but so does the left-speaker
signal after a delay around your head. The same thing occurs symmetrically at your left ear. Each ear receives direct and delayed signals, which
interfere and cause phase cancellations at 2 kHz and above. A centerchannel speaker does not have this response anomaly.
With a phantom center image, the response is weak at 2 kHz because
of the phase cancellation just mentioned. To compensate, recording engineers often choose mics with a presence peak in the upper midrange
for vocal recording. The center-channel speaker does not need this
compensation.
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Practical Recording Techniques
For sharpest imaging and continuity of the soundfield, all the speakers should be:
•
•
•
•
•
•
The same distance from the listener
The same model (except the sub)
The same polarity
Direct-radiator types
Driven with identical power amps
Matched in sound pressure level with pink noise (the sub is 10 dB
louder)
If you are mixing movie soundtracks, the surround speakers should
be dipole designs rather than direct-radiator types. The dipole speakers
project sound forward and backward to create a diffuse effect.
Typically the speakers are 4 to 8 feet from the listener and 4 feet high.
Use a length of string to place the monitors the same distance from your
head. The sub can go along the front wall on the floor. Be sure that all the
speakers sound the same so there is no change in tonal balance as you
pan images around.
A DSP algorithm to reproduce surround sound on headphones has
been developed by Lake Technology. It is licensed to Dolby Labs under
the name “Dolby Headphone.” This feature is beginning to appear in consumer receivers and surround processors.
Setting Up a Surround Monitoring System
Working in surround, of course, requires more equipment than working
in stereo. You’ll need:
• Five “satellite” monitors and a subwoofer, and six channels of power
amplification. Or five powered monitors and a powered sub.
• A sub/satellite crossover (a bass management system). This is built
into some surround monitor packages.
• A six-channel volume control (hardware or software).
Be sure to include a subwoofer in your monitor system. If you don’t,
you might not hear low-frequency noises that a home listener with a
sub will hear. These noises include breath pops, mic-stand thumps, airconditioning rumble, and excessively heavy deep-bass notes.
You could use a home-theater surround receiver for power amplification and bass management. It has a single volume control that simul-
442
Surround Sound: Techniques and Media
19
taneously adjusts the level of all the tracks. Most home-theater receivers
have five amp channels and a line output that feeds a powered subwoofer. The sub’s power amp should be at least 100 watts, and the
receiver should have six analog inputs for your surround mix.
A feature to look for in surround sound receivers is Dolby Digital
and Digital Theater Systems (DTS) decoders (explained later under the
heading “Surround Encoding for DVD”). Receivers labeled “5.1 ready”
or “Dolby Digital ready” are not Dolby Digital compatible. The receiver
must have Dolby Digital and DTS decoders to play those formats.
However, you don’t need those decoders to do surround mixes.
Bass Management
In the surround receiver is a “bass management” circuit. Bass management is nothing more than a subwoofer/satellite crossover filter. It sends
the deep lows to the sub, and sends other frequencies to the five “satellite” speakers that surround you.
A bass management circuit routes frequencies above about 100 Hz
to the five full-range speakers, and routes frequencies below about
100 Hz from all six channels to the subwoofer. In other words, the bass
management circuit routes low-frequency signals from all the five
channels—and the LFE channel—to your sub. By keeping the deep lows
out of the full-range speakers, bass management reduces their lowfrequency distortion and lets them be made relatively small for home
use. Note that bass management affects only what you monitor, not what
you record.
Bass management can be done by a surround-receiver circuit, a
standalone box, a special circuit in a subwoofer, or a software plug-in.
You set the bass management crossover frequency as low as possible to remove the directionality of the bass, and to extend the headroom
of the sub. Typically you’d set the crossover frequency to the frequency
where your full-range speakers are down 3 dB on the low end. If your
five main speakers extend down to 20 or 30 Hz, you don’t need bass management. In some receivers, the bass management crossover frequency is
adjustable among 120/100/80 Hz—whatever your system needs for flattest response.
The crossover frequency is 120 Hz with the Dolby Digital standard
and 80 Hz with the DTS standard. However, the Dolby Digital, DTS, and
THX standard crossover frequencies are irrelevant to the frequency of
the bass-management filter for the mixing work in your studio. And the
443
Practical Recording Techniques
upper frequency limit of the LFE track (125 Hz) has nothing to do with
the crossover frequencies of the bass management (120 to 40 Hz). As mentioned above, you set the crossover frequency according to the frequency
response of your monitor speakers.
LFE Channel Filtering
The LFE channel lowpass filter used in bass management is a very steep
filter (48 dB per octave) so it causes a lot of phase shift. But you can turn
off the LFE filter in the encoder, and use your own gentler filter instead.
Try 80 Hz, 24 dB per octave. Use any filter you like, as long as it removes
all the energy at 125 Hz. Insert this filter between your console’s LFE
channel output and the input of the mixdown recorder’s LFE track. In
other words, record the LFE track pre-filtered, and turn off filtering in the
encoder.
Surround Mixing Equipment
Here’s what you need to mix in surround:
• Multitrack recordings in any format: analog tape, digital tape, hard
disk, etc.
• If you’re using a mixing console, it needs to have at least six output
channels (also called busses or subgroups). Most digital consoles
have a surround matrix, a section set up for mixing and monitoring
in surround.
• If you’re using a console, you need an 8-track recorder (MDM or
hard-disk) to record the surround mix. Tracks 1 through 6 record the
surround channels, while tracks 7 and 8 record a separate stereo mix.
• If you’re using a Digital Audio Workstation (DAW) for surround
mixing, you need an audio interface with at least 8 outputs. Set up
the DAW to feed the 5.1 output channels to six of the interface
outputs, then connect those outputs to your five satellites and subwoofer. M-Audio’s Sonic Theater is a low-cost audio interface and
software that accepts six audio channels from your computer (via
USB) and sends them to your powered surround monitor system. It
can replace the surround receiver mentioned earlier.
• If you’re using a DAW, you need surround mixing software. For
example, MOTU’s Digital Performer and Cakewalk’s Sonar Producer 4.0 include surround mixing. You could mix to six tracks on
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Surround Sound: Techniques and Media
19
your hard drive, and copy the six resulting wave files to a CD or
DVD.
Connections
Now that you know the necessary equipment for surround mixing
(including bass management), you can wire the system together. Two
methods are described below. Method 1 uses an external multitrack
recorder to record the surround mix tracks. Method 2 uses the DAW to
record the surround mix tracks.
Method 1 using an external multitrack recorder: Basically you
connect line-level signals from six busses to the associated tracks on your
mixdown recorder. To monitor those six tracks, connect that recorder’s
outputs either to a surround receiver, or to a bass-management filter that
feeds six channels of power amps. The receiver or amplifiers drive the
five small speakers and the sub.
Figure 19.2 shows the connections. Patch the console’s bus outputs
or surround matrix outputs to the inputs of the 8-track mixdown recorder.
On the back of this recorder, connect track outputs 1 through 6 to the
inputs of the surround receiver or power amp inputs. On the receiver or
power amps, connect the speaker outputs to the speakers. If your subwoofer is self-powered, connect the LFE channel line output to the sub
Figure 19.2 Mixdown and monitoring system for 5.1 surround with an external multitrack recorder.
445
Practical Recording Techniques
line input. If your speakers are self-powered, connect them to outputs 1
through 6 of your bass manager.
When you connect your mixer or DAW to the 8-track mixdown
recorder, which signal goes on which track? The most common track
assignment (the Dolby Digital, ITU, and SMPTE standard) is given below:
1.
2.
3.
4.
5.
6.
7.
8.
Left-front
Right-front
Center
LFE or subwoofer channel
Left-surround
Right-surround
Stereo mix left
Stereo mix right
Be sure to label your tapes or CDs with the track assignment.
Method 2 using the DAW to record the surround mix tracks: Connections for powered monitors are shown in Figure 19.3, top. Set the
overall listening level with your computer surround-monitoring software,
and trim individual speaker levels at each speaker. Connections for
COMPUTER
AUDIO
INTERFACE
PCI, USB or
FIREWIRE
POWERED
SATELLITE
MONITORS
CH 1-6
PCI, USB or
FIREWIRE
COMPUTER
POWERED
SUB WITH
BASS MGT.
CROSSOVER
AUDIO
INTERFACE
SURROUND
RECEIVER
PASSIVE
SATELLITE
MONITORS
CH 1-6
PASSIVE OR
ACTIVE SUB
Figure 19.3 Mixdown and monitoring system for 5.1 surround, using a DAW
as the multitrack recorder. Top: with powered monitors. Bottom: with passive
monitors.
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Surround Sound: Techniques and Media
19
passive monitors are shown in Figure 19.3, bottom. Set the overall listening level with the volume control on the surround receiver. The bass-management filter is built into the powered sub or into the surround receiver.
Calibration
It’s essential to calibrate your speakers so that their levels match. You
need a sound level meter (a low-cost one from Radio Shack is adequate).
Here’s a suggested procedure:
1. Turn on the LFE channel and disable bass management.
2. Set each power amp channel to the same volume setting.
3. Get a pink noise signal from a console noise generator, receiver,
or CD. Connect the signal to a console input. Other options are a
surround calibration DVD, such as the Audio DVD Toolkit from
www.goldline.com, or surround calibration software and an audio
interface, such as M-Audio’s Sonica Theater.
4. Assign that input channel to one surround channel (output bus or
group fader). For example, start with the front-left channel.
5. Set the console’s or DAW’s bus faders and master faders to unity
gain (the shaded portion of fader travel).
6. Adjust the input fader so the level on the mixer’s meter is -20 dBFS
(decibel Full Scale), the standard level for surround mixes. This level
allows for some headroom.
7. Hold the sound level meter at your mixing position and set it to Cweighting, slow response. Aim the meter’s mic at the speaker. Set
the level of the power-amp channel (or the powered monitor) so you
read 85 dBSPL on the meter.
8. Repeat steps 4 through 7 for each channel and its speaker, one at a
time, so that all speakers are putting out the same level. (In most
home-theater receivers is a menu that lets you set the level of each
channel.) If you are mixing for theater sound with dipole speakers,
set their level to 82 dBSPL instead.
9. Assign pink noise to just the LFE channel so that you hear the noise
coming from the subwoofer. The playback level of the LFE channel
is set 10 dB higher than the main speaker levels because that’s done
in consumer surround systems. Using the receiver’s LFE gain
control, or the sub’s level control, set the sub’s SPL to 95 dBSPL if
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Practical Recording Techniques
you’re using an RTA, or to 89 dBSPL if you’re using a sound level
meter.
Why the difference? Unlike an RTA, an SPL meter integrates the energy
of all the octaves it is measuring to come up with a single reading. The
main speakers produce 8 to 10 octaves, but the sub produces 2 octaves.
The sub’s 2-octave energy reads lower on the SPL meter than the main
speakers’ 8- to 10-octave energy. So, instead of setting the sub’s SPL to 95
dB, you set it to 89 dB to allow for this energy difference.
It’s important to phase-align the subwoofer’s signal with the fullrange speakers’ signals. Improper alignment can cause a dip in the
system’s frequency response at the crossover frequency. If your sub has
a phase-matching control, send a sine wave to all speakers at the
crossover frequency. Adjust the phase control to get the loudest sound at
the mix position. If the sub has a polarity switch, try it both ways, and
use the position that gives the loudest bass when all the speakers are
playing.
10. After calibration, record your mixes at 0 dBFS maximum, and set
your master monitor level as desired.
Here’s another calibration method developed by Lorr Kramer of
DTS and surround-sound expert Mike Sokol: Use bandwidth-limited
pink noise (20 to 80 Hz) for the woofer and 500 to 2000 Hz for the main
speakers. Set each speaker to the same SPL, one at a time. Using 500 Hz
to 2 kHz pink noise for the main speakers keeps the signal out of the LFE
channel and avoids exciting room modes. And limiting the top end to
2 kHz helps avoid directionality effects of the mic in the SPL meter.
Now that your monitors are calibrated, do the same for your mixing
console or DAW recording software.
1. Feed pink noise into one channel input module.
2. Route or patch that module’s signal equally to all six surround
output busses.
3. Set each output bus fader to unity gain.
4. At the input module, set the trim to make the output level -20 dB
on the console’s meters.
5. Trim the console’s ADAT or TDIF outputs (if used) so that all six
tracks read -20 dBFS. (The LFE channel does not get 10 dB extra gain
in the recording path, only in the monitoring path.)
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Surround Sound: Techniques and Media
19
6. On your surround receiver, set the small/large speaker switch to
small, and enable bass management.
Recording and Mixing Pop Music for Surround
Doing a multitrack recording for later mixdown in surround is almost
identical to recording for mixdown to stereo. Some engineers add a few
ambience mics to pick up the studio acoustics. These ambience tracks are
panned to the rear speakers during mixdown.
Many producers like to monitor the original recording session in
stereo, not surround, to reduce the technical issues that can slow down
the session. They wait until mixdown to monitor in surround.
Earlier in this book we showed some ways to mix multitrack recordings to 2-track stereo. Now let’s look at mixing those same recordings to
5.1 surround.
Panning
To place the image of each track in space around you, some consoles
include a pair of pan controls (left/right and front/rear) for each channel.
Others use a trackball, mouse, or joystick. Some digital audio editing programs, or plug-ins for those programs, permit surround panning as well.
For example, SmartPan Pro by Kind of Loud Technologies is a surround
panner plug-in for Digidesign’s Pro Tools. Minnetonka’s SurCode is a
program to mix 5.1 surround sound, including a “Build your own mixer”
GUI and automated surround panners.
Suppose your console or recording software has 8 output busses,
and you want to pan or move a track between front-left and rear-right.
Assign the track to the front-left and rear-right busses. They should be
odd-even numbered. When you turn the pan knob from left to right, the
sound image should move as desired.
Where should you pan tracks in a surround mix? There are no set
rules. Some producers like to put all the musicians up front, and put the
hall ambience and applause in the rear. This works especially well for live
concerts and recordings of classical music. This ambience can be created
artificially with a digital reverb, or recorded with mics in the concert hall.
Stereo reverb returns are typically sent to the rear channels. Several multichannel digital reverbs are available, both as hardware and as software.
Some producers use the rear speakers for background vocals,
percussion, horn stabs, or strings, leaving the lead vocal and rhythm
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Practical Recording Techniques
instruments in front. A group of five singers could be panned to place
one singer in each speaker, so that the listener is in the middle of the
group. You might put the lead vocal in the center speaker, and also partly
in the surrounds to pull the vocal out toward the listener. Spreading
instruments between left-front and left-surround, and right-front and
right-surround, gives a greater sense of envelopment.
You can place instruments in fixed positions (static panning), or
move them around in space (dynamic panning). Some consoles let you
move a sound by drawing its path in space on your monitor screen. You
might move a sound along a circle, arc, or line. Then save these pans as
part of your automated mix.
Using the Center Speaker
Some engineers prefer to send center tracks equally to the left and right
speakers—not the center speaker. This creates a phantom center image.
However, sending a track to the center speaker gives a better tonal
balance and more stable imaging than the center phantom image.
It’s not recommended to send a track only to the center speaker.
Some listeners don’t have a center speaker. So if you send, say, a vocal
to just the center speaker, those listeners without a center speaker
won’t hear it. Also, home listeners can solo the center channel and hear
punch-ins on that channel. So many producers route center tracks mainly
to the left and right speakers, and also feed a little signal to the center
speaker (maybe 6 dB down). Some producers don’t use the center speaker
at all.
Using the LFE Channel
With music mixes you seldom need to send anything to the LFE subwoofer track—it gets deep bass from the bass management circuit in the
listener’s playback system, and at the proper level. Because the five main
channels of 5.1 surround encoders reproduce from 20 Hz to 20 kHz,
there’s no need to put anything musical in the LFE channel. The consumer’s bass management filter will redirect any sub-80-Hz energy to
their own subwoofer anyway, whether or not you put this bass signal in
the LFE track. On the other hand, suppose the end listener has a subwoofer/satellite system with six channels, but no bass management
system. In that case, the sound they hear will be thin in the bass if there
is no signal in the LFE channel.
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With film mixes, you typically send low-frequency sound effects
(explosions, tornadoes, crashes) to the LFE channel. The LFE track also
helps with DJ mixes and synth mixes that have lots of lows. Even if you
mix only music, you need a subwoofer to hear the very deep noises
(breath pops, room rumble) that a home listener will hear with a sub.
Downmixing
Downmixing is making a stereo mix from a 5.1 surround mix. It is done
in the consumer’s home theater receiver. In the downmixing circuit, the
left and right surround channels are blended with the left and right front
channels. The center channel is blended equally with the left and right
channels. The LFE channel is either mixed with the front signals or not
used.
Downmixes made this way seldom create a well-balanced stereo
mix, so be sure to check your 5.1 mix for stereo compatibility. Surround
monitoring systems should have a downmix button so you can hear how
your surround mixes will sound when downmixed to stereo by consumer
receivers.
It’s best to do a separate stereo mix and record it on tracks 7 and 8
of your 8-track mixdown deck. This stereo mix can be put on DVD-Audio
discs or Super Audio CDs (explained later) along with the surround mix.
Surround Mix Delivery Format
You will deliver your final 6-track recording to a mastering facility that
will encode it onto a DVD. Supply them either the multitrack mixdown
recording, or a DVD or CD-R with AIFF or WAV files, one for each output
channel. Be sure to label the recording with the track contents. Identify
each track with a recorded slate (front-left, center, sub, etc.). Print a 30second test tone at 1 kHz at -20 dBFS on all tracks. Also include this
information: LFE channel filtered or not, LFE channel filter frequency,
mixdown listening level in dBSPL, sampling rate, bit resolution, SMPTE
format (if included), media formats, program length, intended final audio
sampling rate and bit depth, and a note about any glitches on your
master.
Surround-Sound Mic Techniques
So far we’ve talked about mixing multitrack recordings to surround—a
method intended mainly for pop music. But for classical music, you can
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record in surround using five microphones, which capture the spatial
character of the concert hall in which the musical ensemble is playing.
Each mic feeds a separate track of a multitrack recorder.
Surround mic techniques are somewhat different from stereo mic
techniques. In addition to the usual front-left and front-right mics, you
need two surround mics to pick up the hall ambience, and sometimes a
center mic to feed to the center channel. Note that listening in surround
reduces the stereo separation (stage width) because of the center speaker,
but mic techniques for surround are optimized to counteract this effect.
A number of mic techniques have been developed for recording in
surround. Let’s take a look at them.
Soundfield 5.1 Microphone System
This system is a single, multiple-capsule microphone (Soundfield ST250
or MKV) and Soundfield Surround Decoder for recording in surround.
The decoder translates the mic’s B-format signals (X, Y, Z, and W) into L,
C, R, LR, RR, and mono subwoofer outputs.
Delos VR2 Surround Miking Method
John Eargle, Delos’ director of recording, developed their VR2 (Virtual
Reality Recording) format. Recordings made with this method offer discrete surround. They also are claimed to sound good in stereo and very
good with “steered” analog decoding, such as Dolby Pro Logic.
In making these recordings, Eargle typically uses the mic placement
shown in Figure 19.4. This method employs an ORTF pair in the center,
flanked by two spaced omnis typically 12 feet apart. Two house mics (to
pick up hall reverb) are placed about 23 to 52 feet behind the main pair.
These house mics are cardioids aiming at the upper rear corners of
the hall, spaced about 12 feet apart and about 30 feet high. Spot mics
(accent mics) are placed within the orchestra to add definition to certain
instruments.
The mics are assigned to various tracks of a digital multitrack
recorder:
• 1 and 2: A mix of the coincident-pair mics, flanking mics, house mics,
and spot mics
• 3 and 4: Coincident-pair stereo mic
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Surround Sound: Techniques and Media
Figure 19.4
19
A Delos surround miking method.
• 5 and 6: Flanking mics
• 7 and 8: House mics (surround mics)
NHK Method
The Japanese NHK Broadcast Center has worked out another surround
miking method. They found that, for surround recording, cardioid mics
record a more natural amount of reverb than omni mics. The mics are
placed as described below:
•
•
•
•
A center-aiming mic feeds the center channel.
A near-coincident pair feeds front-left and front-right.
Widely spaced flanking mics add expansiveness.
Up to three pairs of ambience mics aim toward the rear.
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Practical Recording Techniques
Figure 19.5
An NHK surround-sound miking method.
Figure 19.5 shows the mic placement. The front mics are placed at
the critical distance from the orchestra, where the direct-sound level
matches the reverberant-sound level. Typically, this point is 12 to 15 feet
from the front of the musical ensemble and 15 feet above the floor.
NHK engineers make this recommendation: When you’re monitoring the surround program, the reverb volume in stereo listening should
match the reverb volume in multichannel listening. That is, when you
fold down or collapse the monitoring from 5.1 to stereo, the direct/reverb
ratio should stay the same.
The KFM 360 Surround System
Jerry Bruck of Posthorn Recordings developed this elegant surroundmiking method. It is a form of the mid-side (MS) stereo technique.
Bruck starts with a modified Schoeps KFM 6U stereo microphone, which is a pair of omni mics mounted on opposite sides of a 7inch hard sphere. Next to those mics, nearly touching, are two figure-8
mics, one on each side of the sphere, each aiming front and back (Figure
19.6). This array creates two MS mic arrays aimed sideways in opposite
directions. The mics do not seriously degrade each other’s frequency
response.
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Figure 19.6
19
The KFM 360 Surround Miking System.
In the left channel, the omni and figure-8 mic signals are summed
to give a front-facing cardioid pattern. They are also differenced to give
a rear-facing cardioid pattern. The same thing happens symmetrically in
the right channel. The sphere, acting as a boundary and a baffle, “steers”
the cardioid patterns off to either side of center, and makes their polar
patterns irregular.
By adjusting the relative levels of the front and back signals, the user
can control the front/back separation. As a result, the mic sounds like it
is moving closer to or farther from the musical ensemble.
According to Bruck:
The system is revelatory in its ability to recreate a live event. Perhaps
most remarkable is the freedom a listener has to move around and
select a favored position, as one might move around in a concert hall
to select a preferred seat. The image remains stable, without a
discernible “sweet spot.” The reproduction is unobtrusively natural
and convincing in its sense of “being there.
The four mic signals can be recorded on a 4-track recorder for later
matrixing. The figure-8 mics need some equalization to compensate
for their low-frequency rolloff and loss in the extreme highs. To maintain
a good signal-to-noise ratio, this EQ can be applied after the signal is
digitized.
Five-Channel Microphone Array with Binaural Head
This method was developed by John Klepko of McGill University. It combines an array of three directional mics with a 2-channel dummy head
(Figure 19.7):
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Practical Recording Techniques
Figure 19.7
The Klepko surround-sound miking method.
• For the front left and right channels: identical supercardioid mics
• For the center channel: a cardioid mic
• For the surround channels: a dummy head with two pressure-type
omni mics fitted into the ear molds
The mics are shock mounted and have equal sensitivity and equal
gains. Supercardioids are used for the front left/right pair to reduce
center-channel buildup. Although the dummy head’s diffraction causes
peaks and dips in the response, it can be equalized to compensate. During
playback, the listener’s head reduces the acoustical crosstalk that would
normally occur between the surround speakers.
According to Klepko:
The walkaround tests form an image of a complete circle of points
surrounding the listening position. Of particular interest is the
imaging between ±30 degrees and ±90 degrees. The array produces
continuous, clear images here where other (surround) techniques
fail.
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19
The proposed approach is downward compatible to stereo, although
there will be no surround effect. However, stereo headphone reproduction will resolve a full surround effect due to the included binaural headrelated signals. Downsizing to matrix multichannel (5-2-4 in this case) is
feasible except that it will not properly reproduce binaural signals to the
rear because of the mono surrounds. As well, some of the spatial detail
recorded by the dummy-head microphone would be lost due to the usual
bandpass filtering scheme (100 Hz to 7 kHz) of the surround channel in
such matrix systems.
DMP Method
DMP engineer Tom Jung has recorded in surround using a Decca Tree
stereo array for the band and a rear-aiming stereo pair for the surround
ambience (Figure 19.8). Spot mics in the band complete the miking. The
Decca Tree uses three mics spaced a few feet apart, with the center mic
placed slightly closer to the performers. It feeds the center channel in the
5.1 system.
Figure 19.8
A DMP surround miking method.
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Practical Recording Techniques
The rear-aiming mics are either a coincident stereo mic, another
Decca tree, or a spaced pair whose spacing matches that of the Decca tree
outer pair. Jung tries to aim the rear mics at irregular surfaces to pick up
diffuse sound reflections.
Woszcyk Technique (PZM Wedge plus
Opposite-Polarity, 180-Degree Coincident-Cardioid
Surround Mics)
A recording instructor at McGill University, Wieslaw Woszcyk, developed an effective method for recording in surround that also works well
in stereo. The orchestra is picked up by a PZM wedge made of two 18 ¥
29 inch hard baffle boards angled 45 degrees. A mini omni mic is mounted
on or flush with each board. At least 20 feet behind the wedge are the
surround mics: two coincident cardioids angled 180 degrees apart,
aiming left and right, and in opposite polarity (Figure 19.9).
According to Woszcyk, his method has several advantages:
• Imaging is very sharp and accurate, and spaciousness is excellent
due to strong pickup of lateral reflections.
Figure 19.9
458
Woszcyk surround miking method.
Surround Sound: Techniques and Media
19
• The out-of-phase impression of the surround pair disappears when
a center coherent signal is added.
• The system is compatible in surround, stereo, and mono. In other
words, the surround signals do not phase-interfere with the frontpair signals. That is because (1) the surround signals are delayed
more than 20 msec, (2) the two mic pairs operate in separate sound
fields, and (3) the surround mics form a bidirectional pattern in
mono, with its null aiming at the sound source.
If a PZM wedge is not acceptable because of its size and weight,
other arrays with wide stereo separation may be substituted.
Williams Five Cardioid Mic Array
Michael Williams, an independent audio consultant, worked out the
math to determine the best cardioid microphone arrangement for
realistic reproduction of surround-sound fields. His method is shown in
Figure 19.10.
Double MS Technique
Developed by Curt Wittig and Neil Muncy, the double MS technique uses
a front-facing mid-side mic pair for direct sound pickup and a rear MS
pair facing away from the front (Figure 19.11). The rear pair is placed at
or just beyond the critical distance of the room-where the reverberant
sound level equals the direct sound level. The matrixed outputs feed
front-left, front-right, rear-left, and rear-right speakers. No center channel
Figure 19.10
or MMA).
Williams five cardioid mic array (multichannel microphone array
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Practical Recording Techniques
Figure 19.11
Double MS technique.
mic is specified, but you could use the front-facing cardioid mic of the
front MS pair for this purpose.
Surround Ambience Microphone Array
The surround ambience microphone (SAM) array was developed by
Gunther Theile of the Institute für Rundfunktechnik (IRT). Four cardioid
mics are placed 90 degrees to each other and 21 to 25 cm apart. No center
channel is described.
Spider Microphone Array
This system uses a special mic mount with five arms that radiate out from
a center point, like a star. At the end of each arm is a condenser mic
aiming outward from the center. Two examples: The Microtech Gefell
INA 5 uses five M930 mics in shock mounts. In the SPL Atmos 5.1/ASM
5 Surround Recording System, five Brauner condenser mics feed a fivechannel mixing console, which adjusts the mic polar patterns and offers
panning, bass management, and surround monitoring. SPL’s Web site is
www.spl-usa.com. Both systems use the Ideal Cardioid Arrangement
(ICA 5, ITU-775 specification, Figure 19.12) developed by Volker Henkels
and Ulf Herrmann.
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Surround Sound: Techniques and Media
19
Figure 19.12 Ideal cardioid arrangement (ICA) used in Brauner SPL Atmos
5.1/ASM5 Adjustable Surround Microphone.
The Holophone H2-PRO Surround Mic
This is a surround microphone using several omni mic capsules flushmounted in a football-shaped surface. It captures up to eight channels of
discrete surround sound and has eight XLR connectors. See the Web site:
www.holophone.com.
Mike Sokol’s FLuRB Array
This array uses four coincident cardioid mics at 90 degrees to each other
aiming to the front, left, right, and back (Figure 19.13). The four mic
signals feed a matrix processor that delivers the correct signals for 5.1 surround and up to 8.1 surround. The array is compact, relatively low cost,
and convenient to use. Plus, it will sum to stereo or mono without phase
cancellations.
Stereo Pair plus Surround Pair
In this method, the center-channel mic is omitted. You use a standard
stereo pair of your choice to pick up the musical ensemble, plus another
stereo pair of your choice to pick up the hall ambience. The hall mics
feed the left- and right-surround channels. For example, two Crown
SASS-P MKII microphones can be placed back-to-back, separated by
several feet.
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Practical Recording Techniques
SOUND
SOURCE
REAR-AIMING
MIC
MATCHED
CARDIOID
MICROPHONES
SIDE RIGHT MIC
SIDE LEFT MIC
FRONT-AIMING MIC
Figure 19.13
Mike Sokol’s FLRB Array.
You might try a hybrid approach for a pop-music concert: Feed the
front speakers a mix of multiple close-up mics on stage, and feed the rear
speakers the signals from a rear-aiming stereo mic.
Surround Media
So far we’ve discussed surround recordings, and their creation either by
multitrack mixdown or by surround mic techniques. Now let’s turn our
attention to the media that will play those surround recordings. They can
be distributed to the public on CD, Super Audio CD (SACD), or DVD.
Two DVD formats for surround sound are DVD-Audio and DVD-Video.
Let’s examine all these formats in detail.
Compact Disc
The compact disc is a 2-channel format that uses linear pulse code modulation (PCM) encoding. The CD’s bit depth is fixed at 16 bits, and the
sampling rate is fixed at 44.1 kHz. Storage capacity is 640 MB, or about 74
minutes of stereo audio. To fit the six channels of surround into the CD’s
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Surround Sound: Techniques and Media
19
two channels, two data-reduction encoding schemes are used: Dolby
Digital or DTS. We’ll explain them later under the heading “Surround
Encoding for CD.”
DVD
Another medium for playing surround recordings is the Digital Versatile
Disc or DVD. It is a high-capacity optical storage medium the size of a
compact disc (4.73 inches diameter). DVD can store digital data in three
formats: audio, video, and computer.
DVD Compatibility
The DVD player reads:
•
•
•
•
CD
CD-R (in some units)
CD-ROM
DVD-Video disc (video plus audio)
A DVD-Video player can play a DVD-Audio disc if the latter has a
Dolby digital version of the audio in the DVD-Video zone on the disc.
DVD Capacity
Compared to a CD, DVD has much greater capacity due to its smaller
pits and closer tracks. The scanning laser has a shorter wavelength than
in a CD player, which lets it read DVD’s denser data stream. In addition,
MPEG-2 data compression of the video data increases the data density
on the DVD.
Some DVDs have a single layer of pits; others have a dual layer at
different depths. The laser automatically focuses on the required layer.
The Blu-Ray Disc records and plays up to 27 GB of data on a single-sided,
single-layer CD-sized disc using a 405 nanometer blue-violet laser. It uses
MPEG-2 video-recording format and AC3 and MPEG-1 Layer 2 audiorecording format.
Listed below are the storage capacities of various media:
•
•
•
•
A compact disc holds 640 MB.
A single-sided, single-layer DVD holds 4.7 GB (7 times CD capacity).
A single-sided, dual-layer DVD holds 8.5 GB.
A double-sided, single-layer DVD (DVD-RAM) holds 9.4 GB.
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Practical Recording Techniques
• A double-sided, dual-layer DVD holds 17 GB.
• A single-sided, single-layer Blu-Ray Disc holds up to 27 GB.
A DVD with 4.7-GB capacity is enough to hold a 2-hour and 10minute movie plus subtitles.
DVD Players
Most DVD players have these outputs:
• 2-channel analog outputs playing a Dolby-Surround-encoded stereo
signal
• A digital output that can be connected to an external decoder for 5.1channel surround sound (either Dolby Digital or DTS)
• 6 analog outputs fed from built-in Dolby Digital or DTS decoders
(in some units)
DVD Data Rate
The DVD data transfer rate is 10.1 megabits per second (mps). A 6channel surround track, with data compression, consumes 384 or 448
kilobits per second (Kbps). Linear PCM stereo, at 16 bits and 48-kHz sampling rate, takes 1.5 mps. A 96-kHz sample rate doubles the transfer rate
to 3 mps. A 24-bit resolution increases the rate to 4.5 mps.
Two forms of DVD are DVD-Video and DVD-Audio, and we’ll look
at them below.
DVD-Video
DVD-Video is a DVD format for videos: movies with a surroundaudio soundtrack. The audio tracks can be Dolby Digital (AC-3) surround; 5.1 channels, with MPEG-1 compressed audio; or they can be 2
channels, 16- to 24-bit, 48- or 96-kHz, linear PCM audio. In other words,
you can have surround sound with compromised fidelity, or 2-channel
sound with excellent fidelity. A DVD disc can be encoded with both
formats, and listeners can choose which one they want to hear.
Although the spec provides for multichannel PCM audio, current
players have only 2 channels of PCM audio. All players support Dolby
Digital (AC-3) surround.
Many software packages for DVD-Video authoring are easy to use
and cost under $700. Some titles are Sonic Solutions’ DVDit! and MyDVD,
Roxio Toast 5 Titanium, MedioStream neoDVD Standard, Arcsoft
Showbiz, Veritas PrimoDVDFormac Devideo, Cyberlink PowerDVD, and
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Surround Sound: Techniques and Media
19
RecordNow. Several manufacturers of DVD recorders offer bundled DVD
authoring software.
DVD-Audio
DVD-Audio is a DVD format that features audio programs. It also
can have optional still pictures (slide shows), Internet links, visual interactive menus, on-screen text and lyrics, and about 15 minutes of video
clips.
DVD-Audio discs use PCM encoding. This encoding can be linear,
as on CDs, or “packed” using Meridian Lossless Packing (MLP). MLP
reduces the data rate up to 50%, but without any data loss: The reproduced signal is identical, bit for bit, with the original signal. While a
standard CD is a 2-channel format fixed at 16-bit/44.1 kHz resolution,
DVD-Audio is a multichannel surround format with higher resolutions.
Compared to a standard CD, DVD-Audio permits:
• Better fidelity due to higher bit depth and higher sampling rate (up
to 24-bit, 96 kHz with six channels, or 176.4 and 192 kHz with two
channels).
• Longer playing time in some formats (up to 6 hours of 16-bit,
44.1-K stereo).
• More channels (up to six in the 5.1 scheme, allowing surround
sound).
• Optional formats in addition to PCM, such as MPEG-2 BC, DTS,
Dolby Digital, or Direct Stream Digital (DSD; the format used in the
Super Audio CD).
• Option for different sampling rate and bit depth on different channels. DVD-Audio allows a wide range of sampling rates, number of
channels, and quantizations. For example, a 4.7-GB, single-layer disc
can hold a 75-minute program in which the left-center-right signals
are 24-bit/88.2 kHz and the two surround channels are 20-bit/
44.1 kHz.
• Option for different formats on different tracks. One track might be
16-bit/96 kHz surround, while another could be 24-bit/192 kHz
stereo.
• Other optional media formats besides audio. For example, you can
get video content from computer graphics, still photos, tracking over
still photos, and mini-DV camera shots of concerts.
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Practical Recording Techniques
DVD-Audio content is stored in a separate DVD-Audio zone on the
disc (the AUDIO__TS directory). The program can be copy protected by
a digital signature signal and digital watermarking.
Most DVD-Audio players will also play DVD-Videos and CDs, and
some will play Super Audio CDs. A DVD-Video player can play a DVDAudio disc if the latter has a Dolby digital version of the audio in the
DVD-Video zone on the disc. The digital outputs on a DVD-Audio player
include PCM and Dolby Digital. Some units have DTS and DSD outputs,
and all have multichannel analog outputs. Future players might have
FireWire (IEEE 1394) connections.
You compile and record a DVD-Audio disc as you do a CD-R disc:
with software, a hardware disc recorder, and blank discs. Specifically, you
need DVD-Audio authoring software, a DVD-R recorder or DLT tape
backup drive, and blank DVD discs. The write-once discs have dye on
one side like a CD-R. Handling up to 4.7 GB on a single-sided disc, they
can record DVD-Video, DVD-Audio, or DVD-ROM files.
Two major titles of authoring software are Sonic Solutions Studio
HD and DVD Creator for Macintosh G3 or G4. If you want to make pure
audio DVD-Audio discs, Sonic HD will do the job. Just click the mouse
to assemble a playlist of surround-sound tracks. If you want to include
video, etc., Sonic DVD Creator can handle it. In that case, compiling the
DVD-Audio disc can become complex, with a variety of sampling rates,
bit depths, channels, video, interactive menus, and so on. The Web site is
www.sonic.com.
Another major DVD-authoring package is discWelder Bronze by
Minnetonka
software
(www.minnetonkaaudio.com,
www.
discwelder.com). This low-cost program lets you record PCM stereo files
up to 24-bit, 192 kHz and PCM 5.1 files up to 24-bit, 48 kHz to DVDAudio, using a computer DVD recorder.
Super Audio CD
An alternative to DVD-Audio is the Super Audio CD developed by Sony
and Philips. It uses the Direct Stream Digital (DSD) process, which
encodes a digital signal in a 1-bit (bitstream) format at a 2.8224 MHz sampling rate. This system offers a frequency response from DC to 100 kHz
with 120-dB dynamic range.
The Super Audio CD has two layers that are read from one side of
the disc. On one layer is a 2-channel stereo DSD program followed by the
same program in six channels for surround sound. On the other layer is
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Surround Sound: Techniques and Media
19
a Red-Book 16-bit/44.1 K program, which makes dual inventories unnecessary. The 16-bit/44.1 kHz signal is derived from Sony’s Super Bit
Mapping Direct processing, which downconverts the bitstream signal
with minimal loss of DSD quality. Standard CD players can play the 16bit/44.1 kHz layer, and future players would be able to play the 2- or 6channel DSD layer for even better sound quality.
The TASCAM DV-RA1000 records DSD audio or high-resolution
DVD audio—up to 24-bit/192 kHz—to DVD blanks. This standalone unit
also records standard CD-DA, wave, and DSDIFF files to CD and DVD
discs.
Encoding Surround for Release on
Various Formats
As we said, surround mixes can be released on CD, DVD-Video, DVDAudio, or Super Audio CD (SACD). We need to consider how to get six
channels of surround audio onto those formats.
In the past, DVD-Video discs and videocassettes used Dolby Surround—a matrix encoding system that combined four channels (left,
center, right, surround) into two channels. The Dolby Pro Logic decoder
in the consumer playback system unfolded the two channels back into
four. The surround channel, which was mono and limited bandwidth,
was reproduced over left and right surround speakers. Unfortunately,
matrixing reduced the separation between channels because it mixed the
channels together.
Recent encoding schemes let us encode six channels of surround
audio onto disc, while keeping the channels discrete (not matrixed
together). Let’s look at how this is done for CD, DVD-Video, and
DVD-Audio.
Surround Encoding for CD
A CD has only enough capacity for two channels of audio. So to get six
channels of surround audio onto CD, data reduction is needed. Two datareduction schemes are Dolby Digital and DTS.
Dolby Digital and DTS
Dolby Digital and DTS each use a different lossy encoding process to
reduce the bit rate needed to transmit the six channels via a 2-channel
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Practical Recording Techniques
bitstream. “Lossy” means that the reproduced signal is missing some data
that appeared in the original signal, so there is a slight loss in sound
quality.
Why is this data reduction necessary? Audio at 44.1-kHz sampling
frequency and 16-bit word length flows at a rate of about 700 Kbps for
each channel. The rate for six channels is 4.2 Mbps. In order to handle this
huge data flow, data reduction is needed. The data-reduction encoder in
Dolby Digital is AC-3. It can be used on any number of channels.
First used in movie theaters, Dolby Digital and DTS are perceptual
coding methods. They use data reduction (data compression) to remove
sounds deemed inaudible due to masking. Dolby Digital’s AC-3 encoder
compresses the data about 12 : 1, while DTS compresses about 3 : 1. Both
formats offer six discrete channels of digital surround sound. DTS resolution is 20-bit, while Dolby Digital is 16, 18, or 20 bits (perhaps 24 bits
in the future). Dolby’s AC-3 encoder accepts data at sample rates of 32,
44.1, or 48 kHz; DTS accepts 44.1 kHz. Compared to Dolby Digital, DTS
uses less data compression and needs more data storage space and bandwidth. But some listeners say that DTS sounds more transparent—more
like the original discrete tracks that were fed into the DTS encoder. Still,
Dolby is the most common format.
To play a Dolby Digital or DTS recording, you need a newer DVD
player or a CD player with a digital output. Plug the digital output into
a decoder, which extracts the six channels of digital audio and converts
them to analog. The decoder has a DSP chip that can decode both the
DTS and Dolby Digital formats. Some surround receivers have DTS and
Dolby Digital decoders built in.
Surround Encoding for DVD-Video
In a DVD-Video disc, much of the disc’s capacity is taken up by video
signals. So this format also can handle only two channels of audio. DVDVideo uses Dolby Digital’s AC-3 scheme to encode (data-reduce) the six
channels of surround into two channels. During playback, the two channels are decoded to recover the six channels. As we said, those six channels are separate or discrete—not matrixed.
Surround Encoding for DVD-Audio
A DVD-Audio disc has lots of capacity for audio signals. The six channels can be encoded without any data loss by using MLP.
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Surround Sound: Techniques and Media
19
Summary of Media Formats
Let’s summarize the surround encoding schemes used in different media:
• CD uses DTS or Dolby Digital. Both are lossy systems.
• DVD-Video uses Dolby Digital, a lossy system.
• DVD-Audio uses MLP, a lossless system.
However, a DVD-Audio disc also can include Dolby Digital mixes
so that it will play on CD players and DVD-Video players.
Table 19.1 summarizes the sample rate, the resolution (bit depth),
and the stereo or surround systems associated with various media
formats. Figure 19.14 summarizes the types of data handled by various
formats of surround media and players.
Encoding Hardware and Software for CD and
DVD-Video
With the CD and DVD-Video formats, the surround encoding can be done
either by you or by the mastering house that manufactures the disc. To
do it yourself you need a hardware or software encoder. Some examples
of software encoders are Minnetonka Audio’s SurCode CD Pro DTS and
SurCode Dolby Digital, Sony Media Software’s 5.1 Surround Plug-in
Pack, Sonic Foundry’s SoftEncode 5.1 Channel, or Kind of Loud’s SmartCode Pro/DTS plug-in for the Pro Tools platform. If you’re using a hardware encoder, connect its inputs to the outputs of your 8-track mixdown
deck, in parallel with the connections to the monitor system.
Surround-sound expert Mike Sokol suggested a way to put Dolby
Digital or DTS encoded surround mixes on a CD-R. Load the six audio
Table 19.1 Parameters of Surround Media Formats
Format
Sample rate
Resolution
Stereo/surround systems
CD
SACD
DVD-V
44.1 kHz
2.82 MHz
48 kHz
16-bit
1-bit
16- or 24-bit
DVD-A
48 kHz
96 kHz
192 kHz
16-bit
24-bit
24-bit
Stereo PCM. 16-, 20-, or 24-bit DTS (6 channels)
DSD (2 or 6 channels)
Stereo PCM, Stereo MPEG-2, Dolby Digital, or
DTS (2 to 6 channels)
Dolby Digital (6 channels)
PCM encoded with MLP (6 channels)
PCM encoded with MLP (stereo)
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Practical Recording Techniques
SURROUND MEDIA FORMATS
6 digital tracks in
Dolby Digital AC-3 Encoder
(hardware or software)
ENCODERS
6 channels of digital
audio to DVD-A recorder
MEDIA
CD disc
16-bit/44.1 kHz stereo PCM
Dolby Digital
(AC-3)
OR
(not for
commercial
release)
PLAYER
AY S
DTS
OR
DTS Encoder
(hardware or software)
2 encoded surround channels
out to CD or DVD recorder
DVD-Audio disc
DVD-Video disc
(PCM or MLP)
Dolby Digital
Up to 6 ch.
or DTS
24/96 PCM OR
6 ch. encoded
to 2 ch. with
data reduction
Graphics
DSD
2-channel
Dolby Digital
6 ch. encoded OR PCM with no
data reduction
to 2 ch. with
data reduction
CD player with
digital output
Digital out
Dolby
Digital
(or DTS
in DVD-A
only)
DSD format
(2.8 MHz, 1-bit)
2 ch. and 6 ch. DSD on one layer.
2 ch. stereo PCM (16-bit/44.1k)
on 2nd layer.
Internal Dolby
Digital decoder
(or DTS
decoder in
DVD-A only)
SACD player
2 stereo
6 discrete
DSD surround DSD
channels
channels
SACD
Digital out
Figure 19.14
SACD disc
DVD-A or DVD-V player
PCM
2 channel
16-24 bits
48 or 96 kHz
Dolby Digital / DTS
decoder
Six channels
of analog out
6 channels of digital
audio to SACD recorder
OR
2 ch. of
analog
out
DSD out
External
Dolby Digital
or DTS
decoder
6 ch. of
analog
out
6 ch. of
analog
out
2 ch. of
analog
out
2 stereo
PCM
16-bit/44.1k
channels
2 ch. of
analog
out
Surround media formats.
tracks as WAV files into your computer and feed them to the encoding
software. Select an AC-3 WAV file output or DTS WAV file output. Encode
the tracks. Finally, burn the resulting WAV file onto a CD-R. To hear the
surround mix, connect the CD player’s digital output to a surround
decoder, such as the one in a surround receiver. Commercially released
CDs must use only DTS. Details are in Mike’s upcoming book entitled
Surround Sound Production.
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Surround Sound: Techniques and Media
19
DVD Pre-Mastering Formats
You don’t necessarily have to buy an encoder; the encoding can be done
by a mastering house or DVD manufacturer. Simply send them your 8track tape. But you might want to put an encoder in your monitor system
in order to hear the effect of the encoder as the end listener will hear it.
Here are acceptable media formats to send to a DVD manufacturer.
For 2-channel stereo, use one of these formats:
• A removable hard drive with SMPTE time code
• DAT with SMPTE
• The digital audio tracks on the video master tape (D-1, D-5, Digital
Betacam, DCT, or D-2)
For 5.1 channel surround, you can use one of these formats:
•
•
•
•
20-bit Alesis ADAT with time code.
Genex magneto-optical 8-track 20-bit machine.
DLT, DVD-R, or Sonic Solutions 24- or 20-bit Exabyte.
Tascam DTRS (DA-38/88/78/98). Record the six audio channels on
tracks 1 through 6. Put SMPTE on track 8, or put a stereo mix on
tracks 7 and 8. For Dolby Digital, track assignments are 1, left; 2,
center; 3, right; 4, LFE (low-frequency effects or subwoofer); 5, left
surround; 6, right surround; 7, data channel; 8, data channel. For
DTS the track assignment is 1, left; 2, right; 3, left surround; 4, right
surround; 5, center; 6, LFE; 7, data; 8, data.
• Or use all eight Tascam DA-88 tracks to simulate six tracks with 20bit resolution. This is done with a Prism MR-2024T processor.
• Pro Tools 24 with Jaz drives.
• Nagra-D is fine for four-channel surround.
If you want to create the LFE or 5.1 channel, you can mix the five
other channels and feed them through a 120-Hz lowpass filter. Note that
most music-only surround mixes don’t use the LFE channel.
You might have video slide-show data that accompanies the audio.
Store the video on a removable hard drive or send the file by modem on
the Internet. TIFF and bitmap (BMP) formats are acceptable.
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Practical Recording Techniques
Dolby Units for DVD Mastering
This information is for those who produce the actual DVD. DVD mastering requires MPEG-2 video and Dolby Digital encoders. You can use
either one for multichannel audio on DVD titles. Dolby Digital soundtracks are compatible with mono, stereo, or Dolby Pro Logic systems.
Dolby encoders and decoders are described on Dolby’s Web site at
www.dolby.com/professional/index.html.
Special thanks to Mike Sokol for his generous technical help with
this chapter.
472
20
PUTTING YOUR MUSIC
ON THE WEB
You’ve recorded a new song and you can’t wait for people to hear it. You
might want to distribute it on the World Wide Web, in addition to (or
instead of) CDs.
Why put your music online? Web excerpts of your songs can entice
listeners to buy your CDs. Making songs available on the Web costs less
than duplicating CDs and selling them in stores. Also, distributing online
can be done much more quickly than distributing CDs. Keep in mind,
though, that it’s hard to get your songs noticed among the millions of
other titles that are online.
Streaming versus Downloading
There are two basic ways to transmit music on the Internet: streaming
files and downloading files. A streaming file plays as soon as you click
on its title. A downloaded file doesn’t play until you copy the entire file
to your hard disk. Streaming audio is heard almost instantly (after the
buffer memory fills), but usually sounds muffled and can be interrupted
by net congestion.
The sound quality of streaming audio depends on the speed of
the modem and ranges from funky AM radio (with a 56K modem) to
473
Practical Recording Techniques
near-CD quality (with a cable modem). With downloaded audio you
must wait up to several minutes to download the song. But when it plays,
the sound is high-fidelity and continuous.
Data Compression
Audio files that you record on your computer are usually WAV or AIFF
files. They have no data reduction (data compression), so they take up
lots of memory. A 3-minute song recorded at 16-bits, 44.1 kHz consumes
about 32 MB. Downloading a 32-MB WAV file on the Web would take
several hours using a 56K modem. So, audio files intended for Web download are generally data-reduced or data-compressed. For example, if
you compressed a 3-minute song by 10 : 1 (as in an MP3 file), it would
consume about 3.2 MB and would download 10 times faster than the
equivalent wave file.
Most types of data compression tend to degrade sound quality. The
sound quality of a compressed-data format depends on its bitrate, measured in kilobits per second (kbps). The higher the bitrate, the better the
sound, but the greater the file size. A bitrate of 128 kbps for stereo MP3
files is considered “near-CD” quality. At low bitrates (below 128 kbps),
you can hear artifacts such as “swirly” cymbals, smeared transients such
as drum hits, a general “phasey” effect, and less treble. At higher bitrates
above 200 kbps, the artifacts start to disappear, and to most listeners the
sound is CD quality.
A stereo MP3 file encoded at 128 kbps is 64 kbps per channel. A mono
MP3 file encoded at 64 k is equal in quality to a stereo MP3 file encoded
at 128 k. Mono files consume half the file space of stereo files if both are
the same bitrate.
Table 20.1 relates MP3 stereo bitrate to sound quality.
Table 20.1 Data Compression Ratio and Sound Quality of Various Bitrates
474
Bitrate
Compression
Sound Quality
8 kbps
64 kbps
128 kbps
320 kbps
176 : 1
20 : 1
10 : 1
4.4 : 1
CB radio quality
AM radio quality
Near-CD quality (22-kHz bandwidth)
CD quality
Putting Your Music on the Web
20
Web-Related Audio Files
You can put audio on the Web in several file formats. Let’s look at some
of the file types in current use.
• WAV: A standard PC format for audio files. It encodes sound without
any data reduction by using pulse code modulation. Audio CD
resolution is 16-bit, 44.1 kHz. Because wave files consume a lot of
memory (about 32 MB for a 3-minute song in stereo), they are seldom
used on the Internet for songs because they take so long to download. This may change when we start using the much faster Internet 2, which employs fiber-optic cables.
• Audio Interchange File Format (AIFF): A standard Mac format for
audio files. Like wave files, AIFF files are not data-compressed.
• MP3 (MPEG Level-1 Layer-3): A format that stores audio in a small
space with high quality. In an MP3 file (.mp3), the data has been
compressed or reduced to one-tenth of its original size or less. Compressed files take up less memory, so they download faster. You
download MP3 files to your hard drive, then listen to them. MP3
audio quality at a 128-kbps rate is nearly the same as that of CDs
(depending on the source material).
• MP3Pro: An improvement over MP3. Songs encoded at 64 kbps
with MP3Pro are said to sound as good as songs encoded at 128 kbps
with MP3. MP3Pro offers faster downloads and nearly doubles the
amount of music you can put on a Flash memory player. MP3 and
MP3Pro files are compatible with each others’ players, but an
MP3Pro player is needed to hear MP3Pro’s improvement in sound
quality.
• MP3 with VBR: MP3 encoding done with variable bitrate, which
depends on the requirements of the signal from one instant to the
next. VBR reduces file size but keeps the audio quality high.
• RealAudio: A highly compressed audio file format used for streaming audio. Generally, RealAudio has lower fidelity (less treble) than
MP3, but the fidelity depends on modem speed and the current
Internet bandwidth. RealAudio files (.ra or. rm) are often used as
short excerpts or previews of songs.
• Windows Media Audio (WMA): Another popular compressed audio
file format for streaming audio and for downloads. Windows Media
475
Practical Recording Techniques
•
•
•
•
9 promises performance similar to MP3Pro: near-CD quality at
48 kbps and CD quality at 64 kbps. For more information see
www.microsoft.com/windows/windowsmedia/default.aspx.
OGG (Ogg Vorbis): A new compressed audio format, Ogg Vorbis
is license-free open software. For a given file size, Vorbis sounds
better than MP3. Vorbis takes up less file size than MP3 files of
equal quality. For more information see www.xiph.org and
www.vorbis.com.
MPEG Advanced Audio Coding (AAC): A relatively new compressed audio file format, AAC is intended to replace MP3. AAC
offers better sound quality than MP3 at the same bitrate. Many listeners claim that AAC files made at 128 kbps sound like the original
uncompressed audio source. What’s more, AAC supports multichannel audio and a wide range of sample rates and bit depths. It’s
also used with Digital Rights Management technology by helping to
control the copying and distributing of music.
MID (MIDI, or Musical Instrument Digital Interface): A string
of numbers that represent performance gestures, such as note
on/off, which note is played, key velocity, and so on. See Chapter
16. Because MIDI files do not include audio, they are very
compact.
Rich Music Format (RMF): A MIDI file that might have digital audio
embedded. It’s used with the Beatnik browser plug-in, which plays
RMF files using sampled instruments or custom samples triggered
by the MIDI data. Beatnik features interactive control of the music.
There are many other formats—some of which include video—but
MP3, Windows Media, and RealAudio are currently the most popular
audio formats on the Internet. For more information on using Windows
Media, see www.microsoft.com/windows/windowsmedia/.
Currently, Windows Media and RealAudio are the most popular
streaming types, and MP3 and Windows Media are the most popular
download types. CD track 41 demonstrates MP3 and WMA data
compression.
What You Need
To put your music on the Web, you need to download a few pieces of
software, which are low-cost or free:
476
Putting Your Music on the Web
20
• Audio editing software: A program that takes an audio signal
through a sound card and records the audio on your hard drive.
Most programs let you edit the audio on-screen with a mouse, then
save the edited program as a WAV or AIFF file. Examples are
Windows Sound Recorder, MusicMatch Jukebox from www.musicmatch.com, Adobe Audition, Cakewalk Home Studio and Sonar,
emagic Logic, Steinberg Cubase, MOTU Digital Performer, SAW
Studio, and Pro Tools.
• Ripper: A program that converts audio from a CD or CD-R to a WAV
file.
Examples
are
MusicMatch
Jukebox
from
www.musicmatch.com,
Xing
Audiocatalyst
from
www.real.com/accessories,
and
Windows
Media
Player
from www.microsoft.com/windows/windowsmedia. Not all CDROM drives support ripping.
• MP3 Encoder: A program that converts a WAV or AIFF file to an MP3
file. Examples are AltoMP3 from www.Yuansoft.com, SoloH mpeg
Encoder from www.mp3proclub.com, and dBPower Amp from
www.dbpoweramp.com. Some other sites for encoders are
www.team-mp3.com and www.liquidaudio.com. Some audio
editing software includes an MP3 encoder.
• WMA Encoder: A program that converts a WAV or AIFF file to a
WMA file. It’s a free download from Microsoft at www.
microsoft.com/windows/windowsmedia/download/default.asp.
Select Windows Media Encoder. Windows Media Technologies has
Digital Rights Management, which limits who can hear your music.
Another source is www.team-mp3.com.
• Ogg Vorbis Encoder (optional) from www.vorbis.com. Converts CD
tracks or wave files to Vorbis format. For a given file size, Vorbis
sounds better than MP3. Vorbis takes up less file size than MP3 files
of equal quality.
• RealAudio Encoder (optional): A program that converts a WAV
or AIFF file to a RealAudio file for streaming. Examples are
RealProducer or RealProducer Plus from www.real.com/
products/tools/producer/index.html.
To listen to your music that you put on the Web, you need:
• MP3 Player: A program or a device that plays MP3 files. Some software player examples are MusicMatch Jukebox from www.musicmatch.com, Winamp from www.winamp.com, Windows Media
477
Practical Recording Techniques
Player
from
www.microsoft.com/windows/mediaplayer,
RealPlayer from www.real.com, MacAMP from www.macamp.net,
and QuickTime-4 in Apple’s OS. Portable MP3 players play MP3
files downloaded from the Web.
• RealAudio Player: A free program that plays RealAudio streaming
files. Examples are RealNetwork’s RealPlayer from www.real.com
or Windows Media Player (below).
• Windows Media Player: Although intended to play mainly
Windows Media files, this free program plays many file types: .avi,
.asf, .asc, .rmf, .wav, .wma, .wax, .mpg, .mpeg, .m1v,.mp2, .mp3,
.mpa, .mpe, .ra, .mid, .rmi, .qt, .aif, .aifc, .aiff, .mov, .au, .snd, .vod.
This player is a free download from www.microsoft.com/windows/
windowsmedia/download/default.asp. Another source is www.
winamp.com.
• Ogg Vorbis player (optional) such as Winamp.
All-in-one software combines several of these functions in one
program. RealJukebox Plus from www.real.com and MusicMatch
Jukebox from www.musicmatch.com are MP3 player/ripper/ encoders.
Xing-Tech’s Audio-Catalyst from www.real.com\accessories is a
ripper/encoder that converts CD data directly to MP3. Another source
for players, rippers, and encoders is www.team-mp3.com. Some digital
audio editing programs can output MP3, WMA, and RealAudio files.
How to Upload Compressed Audio Files
Got everything you need? Let’s go. Basically, here’s what you will be
doing:
1. Convert your song from a cassette, DAT, or CD to a WAV file by
using audio editing software. Or convert your song from a CD to a
WAV file by using a ripper.
2. Edit and process the WAV file to optimize it for the Internet.
3. Then use an encoder to convert the WAV file to an MP3, RealAudio,
or WMA file.
4. Finally, send (upload) the converted file to a Web site that features
music in the MP3, RealAudio, or WMA format.
Let’s go over the procedure in more detail. You can substitute WMA
or RealAudio for MP3 in the procedure below.
478
Putting Your Music on the Web
20
1. Start with a cassette, DAT, or CD recording of a song.
2. If you have a cassette, plug your cassette-deck line outputs into your
sound card’s line input. If you have a DAT, plug your DAT recorder
analog outputs into your sound card’s line input. If your sound card
has a digital input, connect it to your DAT recorder’s digital output.
3. If your source is a cassette or DAT, use the editing software to copy
the recording to your hard disk. If the source is a CD or CD-R, put
it in your CD-ROM drive. Turn off all other programs. Then use a
ripper to convert the CD audio file to a WAV file on your hard drive.
(Not all CD-ROM drives support ripping.)
4. Edit the start and stop points of the song. You might want to edit a
30-second excerpt of a song to use as a preview of your music. If so,
add a fade-in and fade-out to the preview.
5. Next, you might want to process the audio so that it will sound
louder and clearer when played on the Web. To do this, reduce the
bandwidth: apply low cut below 40 Hz and high cut above 15 kHz.
You might want to try a higher frequency low cut and a lower frequency high cut. Apply compression or multiband compression,
apply peak limiting, then normalize the song to maximize its level.
6. Save the edited, processed song as a WAV file (PC) or AIFF file (Mac)
on your hard drive.
7. Use an MP3 encoder to convert the song’s WAV or AIFF file to
an MP3 file on your hard drive. You might want to use a bitrate of
128 kbps, which many Web sites require. It’s a good compromise
between file size and sound quality. A 3-minute MP3 song encoded
at 128 kbps typically is 3 MB in size. Higher bitrates give better sound
but longer download times. A file encoded at 256 kbps sounds the
same as CD, but is one-sixth the file size.
You might want to convert the excerpt’s WAV or AIFF file to a RealAudio file by using a RealAudio encoder. Note: Some Web sites—such as
www.iuma.com—automatically create a RealAudio file from your
uploaded MP3 file.
8. Next you will upload your MP3 files to an MP3 server—a Web
site that accepts MP3 files for distribution on the Web. Examples
are www.iuma.com, www.peoplesound.com, or www.AWAL.com.
(Also see the MP3 Links page at www.team-mp3.com.) Some sites
offer free downloads of their music files; others charge the listener
so that you make some income.
479
Practical Recording Techniques
Point your Web browser to the desired site. Then click on the button
labeled “Artists Only,” “Submit your music,” or something similar.
This is where you upload your MP3 files.
9. Once you sign up and fill out some forms, click on “Upload” (or
whatever). With a 56K modem, an upload of one 3-minute song
might take up to 30 minutes. You can also upload scanned photos
of your band, your album cover, and text describing your band and
its music. Some sites take a few days to approve your songs.
Congratulations—you’re on the Web!
Putting Your Music on Your Web Site
Does your band have a personal Web site? You’ll want to put samples
of your music there. So far I’ve covered how to upload your songs to
an MP3 server such as www.iuma.com. Now I’ll explain how to put
your songs on your own Web site. People visiting your site can click on
a song title to hear a streaming song preview, or to download an entire
song.
Let’s start by creating a Web-page link to each MP3 file. It’s easy. You
can create the link with Web-page design software or with one line of
HTML code.
Putting MP3 or WMA Files on Your Site
Again, you can substitute WMA for MP3 in the procedure below.
1. Suppose you have a song on CD called “Blues Bash.” Using ripper
software, transfer that song to your hard drive as a WAV file (PC) or
AIFF file (Mac). In this example, we’ll call the file BLUES.WAV. If
you have a ripper/encoder, convert that song to an MP3 or WMA
file and go to Step 3.
2. Use an MP3 encoder to convert the WAV file to an MP3 file. I recommend a setting of 128 kbps bitrate, stereo for MP3 files. This
setting gives hi-fi sound with a relatively small file, so it’s
fairly quick to download. You now have an MP3 file called
BLUES.MP3.
3. In your computer, move BLUES.MP3 to the same directory on your
hard drive that your Web page is in. Use Web-page design software
to open your band’s Web page. Here we’ll call it PAGE1.HTM. On
480
Putting Your Music on the Web
20
that page, where you want the song title to appear, type in the title
of the song. In this example it’s “Blues Bash.” Link that title to
BLUES.MP3.
When you left-click on the song title, BLUES.MP3 should load and
play. When you right-click on the song title, you can select “Save Target
As” to copy the MP3 file to a directory on your hard drive.
If you want to use HTML code:
1. Open your Web page with a browser such as Windows Explorer.
2. Select View > Source. You’ll see the HTML code for that page in plain
text format.
3. Find a spot on the page where you want the song title to appear.
Type in the title of the song and the link to its MP3 file. In HTML it
would look something like this:
<a href = “blues.mp3”>Blues Bash</a>
For a WMA file it would be
<a href = “blues.wma”>Blues Bash</a>
4. Save and close the text file, go to Windows Explorer, and select View
> Refresh. You should see the link to the MP3 or WMA song. When
you left-click on the link, you should hear the song. When you rightclick on it, you can select “Save Target As” to copy the MP3 file to a
directory on your hard drive.
Now that your song links are working correctly on your computer,
its time to upload them.
1. Upload (send) PAGE1.HTM and BLUES.MP3 to your Web server.
Make sure that both files go to the same directory. Some Web servers
have an upload page for this purpose. If yours doesn’t, you can
upload the files using file transfer protocol (ftp) client software. Do
a Web search for ftp freeware, such as www.freshmeat.net/search/?
fourohfour=1&q=ftp.html. Note: Some Web servers do not allow
MP3 files. Find the page on the Web server site that tells what files
they permit.
2. Now start your Web browser and go to PAGE1.HTM on your site.
Click “Refresh” in your browser so that you see the PAGE1.HTM
that you just uploaded.
481
Practical Recording Techniques
3. Left-click the song title (in this case, “Blues Bash”), and it should
play after the buffer fills. Or right-click the song title and select “Save
Target As.” The song should download over a few minutes. Then
you can play it with your MP3 player or WMA player in glorious
hi-fi stereo.
Putting RealAudio Files on Your Site
Now let’s consider streaming audio. If you are running your own Web
site from your own computer, you need RealAudio server software, such
as RealAudio Basic Server at www.real.com/products. Setting up your
own server is beyond the scope of this book.
If your Web site is hosted on someone else’s computer, you don’t
need server software. For example, if you have a free Web site at
www.Geocities.com, they already have a RealAudio server, so you don’t
need one.
Download the free RealProducer software from www.real.com.
RealProducer Plus is another option. Also download the latest free
RealAudio player (RealPlayer) from www.real.com.
Now decide what music you want to stream. Generally, you’ll want
your streaming audio files to be short samples or “clips” of your music,
but they can be entire songs. Let’s start by creating a short sample.
1. Suppose you have a song on CD called “Blues Bash.” Using ripper
software, transfer your song onto your hard drive as a WAV file
(PC) or AIFF file (Mac). In this example, we’ll call the file
BLUES.WAV.
2. Load BLUES.WAV into your digital editing software. Trim it to about
30 seconds long. Fade out the music toward the end. In this example,
let’s save the edited song as BLUES2.WAV.
3. Use RealProducer to convert BLUES2.WAV into BLUES2.RM, which
is a RealMedia file.
4. Next, use a word processor or text editor (such as Notepad) to create
a small text file that points to the location of your RealMedia file; for
example; www.webserver.com/mywebsite/blues2.rm.
Fill in your own Web server and the URL of your Web site. Save this
line in your Web page directory on your hard drive as a plain ASCII text
file with a.RAM extension. In this case, you’d call it BLUES2.RAM. This
type of file is called a metafile.
482
Putting Your Music on the Web
20
5. Using Web-page design software, open your Web page on your hard
drive. Here we’ll call it PAGE1.HTM. Find a spot where you want
the song title to appear. Type the song title, such as “Blues Bash.”
Link that title to BLUES2.RAM. In HTML it would look something
like this:
<a href = “blues2.ram”>Blues Bash</a>
In your Web page, left-click on the song link. It should play.
Important: Don’t link your song title directly to the sound file
BLUES2.RM. Instead, link it to the text file (metafile) called
BLUES2.RAM, which you just created. This metafile makes the
RealPlayer pop up and play the streaming audio. If you incorrectly link
your song to BLUES2.RM, and a listener clicks on “Blues Bash,” that file
will download instead of streaming.
Now that your song links are working correctly in your computer,
it’s time to upload them.
1. Upload (send) PAGE1.HTM, BLUES2.RAM, and BLUES2.RM to
your Web site. Be sure they all go to the same directory (your Web
site directory). As we said before, some Web servers have an upload
page. If yours doesn’t, try uploading the files with ftp software. You
might want to search for ftp freeware on the Web.
2. Now start your Web browser and go to your site. Open
PAGE1.HTM. Then click “Refresh” in your browser so that you see
the current page, not the one in your cache.
3. Click on the song title. In a few seconds RealPlayer should pop up,
fill the buffer memory, and play the tune. If not, recheck everything
you typed. Then try www.real.com for tech support.
An important part of this process is providing the right bitrate for
your target audience. When you use RealPublisher, you might create one
file suited for a 28K modem, and another file for a 56K modem. Why use
both formats? The faster the modem speed, the better the sound quality
(more extended highs). So a file optimized for a 56K modem sounds
better than a file made for a 28K modem. However, a 28K modem can’t
play 56K modem files without skipping, so you need both formats. If you
are working in RealPublisher’s Advanced mode, select “mono” because
it gives brighter sound than “stereo” for the same bitrate.
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Practical Recording Techniques
Play low-fi “Tango” sample (28K modem)
Play low-fi “Tango” sample (56K modem)
Right-click to download hi-fi “Tango” sample in MP3 format
Right-click to download hi-fi “Tango” sample in WMA format
Figure 20.1 Sample Web-page song links with four song formats: RealAudio
for 28K modem, RealAudio for 56K modem, MP3, and WMA.
Examples of Web-page Song Links
Figure 20.1 shows some examples of Web-page song links with four
formats: RealAudio for 28K modem, RealAudio for 56K modem, MP3,
and WMA. Below Figure 20.1 is the HTML code for that page.
The methods described here will provide streaming audio and
downloadable audio from any HTTP server.
<a href = “tango28.ram”>Play low-fi “Tango” sample (28K modem)</a> <br>
<a href = “tango56.ram”>Play low-fi “Tango” sample (56K modem)</a> <br>
<a href = “tango.mp3”>Right-click to download hi-fi “Tango” sample in
MP3 format</a> <br>
<a href = “tango.wma”>Right-click to download hi-fi “Tango” sample in
WMA format</a>
The code <br> above means a line break.
Streaming Audio from a RealServer Site
Now we’ll look at ways to stream audio from a RealServer (RTSP) site,
which has some advantages.
In your Web surfing, have you ever clicked on a song title to hear
the music, only to have it interrupted? You try to play a streaming audio
file, but it skips instead of playing continuously. One cause is too much
traffic on the Internet. Your connection speed to the Net changes continuously depending on how many folks are using it the same time you are.
If your connection speed is too slow to keep up with the streaming file’s
bitrate, the sound skips.
484
Putting Your Music on the Web
20
Is there a way to play streaming files that adapts to changing connection speeds? There is, and it’s called SureStream. Developed by RealNetworks, SureStream is a file format for streaming audio files that varies
the bitrate to match what your modem can handle at the moment. The
sound quality varies with the bitrate—sometimes bright, sometimes dull.
But at least the stream is continuous. No skipping—unless traffic is really
bad. With SureStream, you don’t need to offer several audio files at different bitrates to handle different modem speeds. One SureStream file can
work for any modem.
If you’d like to have SureStream ability on your Web site, have your
Web page hosted by a server who has RealServer software. Geocities.com
is one example. If you are a member of Geocities, and you are a member
of their Geomedia group, you can access their RealServer and play SureStream files from your Web site.
There are two ways to stream RealAudio files: via Hyper Text Transfer Protocol (HTTP) or Real Time Streaming Protocol (RTSP). Any standard Web server is HTTP format. Earlier in this chapter we looked at
ways to stream your music from any Web-site host using HTTP. Now
we’ll cover streaming from a Web-site host that has RealServer.
Setting Up RealServer Files with RealProducer
Imagine that your band’s Web page is on a RealServer host, and you
want to add SureStream RealAudio files to your page. Here’s how to go
about it.
First, download the free RealProducer software from www.
realnetworks.com/products/producer/index.html. RealProducer Plus is
another option. Also download the free RealAudio player from
www.real.com.
Note: Your Web server might require a special version of RealProducer that you download from the server. For example, Geocities says
that you must download and use the Geomedia-optimized RealProducer;
otherwise your files won’t play correctly. You might need to become a
RealMedia member in your Web server. For instance, the Geocities Web
server has a RealMedia option called Geomedia. Once you’ve subscribed,
you can use their RealServer to play SureStream files.
Now decide what music you want to stream. Generally, you’ll want
your streaming audio files to be short samples or “clips” of your music,
but they can be entire songs. Let’s start by creating a short sample.
1. Suppose you have a song called “Blues Bash” recorded on your hard
drive as BLUES.WAV. Load the file BLUES.WAV into your digital
485
Practical Recording Techniques
2.
3.
4.
5.
6.
editing software. Trim it to about 30 seconds long. Fade out the
music toward the end. In this example, let’s save the edited song as
BLUES2.WAV.
Use RealPublisher to convert BLUES2.WAV into BLUES2.RM, which
is a RealMedia file. In this process, select “SureStream” file rather
than “Fixed Rate” file. If you are working in RealPublisher’s
Advanced mode, select “mono” because it gives brighter sound than
“stereo” for the same bitrate.
If you wish, use RealPublisher’s Web Page Wizard to create a Web
page, such as PAGE1.HTM. This page includes the song title, such
as “Blues Bash.” You can add more text and graphics to the page.
The Web Wizard will also create a short text file called a metafile. Its
filename is BLUES2.RAM (for a pop-up player) or BLUES2.RPM (for
an embedded player). A pop-up player appears only when you click
on a song title. An embedded player is part of a Web page. In
working with the Web Page Wizard, try to use the default settings.
Be sure that BLUES2.RM, BLUES2.RAM, and PAGE1.HTM are all
saved in the same directory on your hard drive.
Use RealPublisher’s Publishing Wizard to upload those three files to
your Web site. If for some reason it doesn’t work, go to your Web
site and upload those three files from there. They should all go to
the same directory (your Web page directory).
At your Web site, open PAGE1.HTM (or whatever). Click “Refresh”
so that you see the current version, not the one in your cache.
Click on the song title. The RealPlayer should pop up and play the
song. If you selected “Embedded Player” when you created the song
file, you should see a RealPlayer on your Web page. Click the PLAY
button to hear the song. Note: If Internet traffic is high, you might
get an error message saying “Requested file not found” even though
the file is there. You might have to wait for a less busy time.
Setting Up RealServer Files Without RealPublisher
You can do all the above without RealPublisher by following the procedure below:
1. Using a word processor or text editor (such as Notepad), create a
small text file that points to the location of your RealMedia file. For
example:
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Putting Your Music on the Web
20
rtsp://real.webserver.com/your Web site address/blues2.rm.
Replace “webserver.com” with your own Web server; for example, geocities.com. Save this line as a plain ASCII text file with a .RAM extension.
In this case, you’d call it BLUES2.RAM. This type of file is called a
metafile. Save it in your Web site’s directory on your hard drive.
The URL above has three parts:
• The protocol
• The server
• The address
The protocol part is rtsp:, which stands for Real Time Streaming Protocol—used by the RealNetworks server. The server part is real.webserver.com, which points to the Web server’s address. The “real” at the
beginning directs your request to the RealNetworks servers. The address
part includes your entire Web server and Web site address, along with
the audio filename.
2. Now use Web-page design software to open your Web page on your
hard drive. Here we’ll call it PAGE1.HTM.
3. Find a place on the page where you want the song title to go. Type
the title of the song, such as “Blues Bash.”
4. Link that title to the metafile you just wrote and saved (in this case,
link it to BLUES2.RAM). In HTML it would look something like this:
<a href = “blues2.ram”>Blues Bash</a>
Important: Don’t link your song title directly to the sound file
BLUES2.RM. Instead, link it to the text file (metafile) called BLUES2.RAM
that you created earlier. This metafile makes the RealPlayer pop up and
play the streaming audio. If you incorrectly linked your song to
BLUES2.RM, and a listener clicks on “Blues Bash,” that file will download instead of streaming.
Now that your song links are working correctly on your computer,
it’s time to upload them.
1. Upload (send) PAGE1.HTM, BLUES2.RAM, and BLUES2.RM to
your Web site. Be sure they all go to the same directory (your Web
site directory).
2. Now start your Web browser and go to your site. Open
PAGE1.HTM. Then click “Refresh” in your browser so that you see
the current page, not the one in your cache.
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Practical Recording Techniques
3. Click on the song title. In a few seconds RealPlayer should pop up,
fill the buffer memory, and play the tune. If not, re-check everything
you typed. Also, net congestion or Web-server glitches can cause
false error messages. Try again when the Net is not so busy. If all
else fails, contact tech support at your Web server and at
www.real.com.
The methods described here will provide streaming audio from any
Web host that offers RealServer. I hope to hear your music on the Web!
Liquid Audio
An online music service you should know about is Liquid Audio
(www.liquidaudio.com). This server company provides music retailers
and record labels a secure way to sell and distribute high-quality audio
tracks on the Internet, with Digital Rights Management. Once you open
an account with Liquid Audio, you have access to software that encodes
your music to the high-quality AAC format and uploads it to the Liquid
Audio server. The encoder adds to the file an inaudible digital “watermark,” which tracks the song owner and controls copies.
To hear your music, listeners download the free Liquid Player. It
plays free preview clips and handles a variety of file types. It also lets the
user purchase full-length tracks online. In addition, the player displays
graphics, liner notes, lyrics, and promotional material, and includes CD
burning software.
488
A
dB or not dB
In the studio, you need to know how to set and measure signal levels and
match equipment levels. You also need to evaluate microphones by their
sensitivity specs. To learn these skills, you must understand the decibel—
the unit of measurement of audio level.
Definitions
In a recording studio, level originally meant power, and amplitude
referred to voltage. Today, many audio people also define “level” in terms
of voltage or sound pressure, even though this terminology is not strictly
correct. You should know both definitions in order to communicate.
Audio level is measured in decibels (dB). One dB is the smallest
change in level that most people can hear—the just-noticeable difference.
Actually, the just-noticeable difference varies from 0.1 dB to about
5 dB, depending on bandwidth, frequency, program material, and
the individual. But 1 dB is generally accepted as the smallest change in
level that most people can detect. A 6- to 10-dB increase in level is considered by most listeners to be “twice as loud.” Sound pressure level,
signal level, and change in signal level all are measured in dB. Play CD
track 42 to hear the effects of various decibel changes on loudness. Track 43
finishes the CD.
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Practical Recording Techniques
Sound Pressure Level
Sound pressure level (SPL) is the pressure of sound vibration measured
at a point. It’s usually measured with a sound level meter in dB SPL
(decibels of sound pressure level).
The higher the sound pressure level, the louder the sound
(Figure A.1). The quietest sound you can hear, the threshold of hearing,
is 0 dBSPL. Average conversation at 1 foot is 70 dBSPL. Average homestereo listening level is around 85 dBSPL. The threshold of pain—so loud
that the ears hurt and can be damaged—is 125 to 130 dBSPL.
Sound pressure level in decibels is 20 times the logarithm of the ratio
of two sound pressures:
dBSPL = 20 log P/Pref
where P is the measured sound pressure in dynes/cm2, and Pref is a
reference sound pressure: 0.0002 dyne/cm2 (the threshold of hearing).
Signal Level
Signal level also is measured in dB. The level in decibels is 10 times the
logarithm of the ratio of two power levels:
Figure A.1
490
A chart of sound pressure levels.
A
dB or not dB
dB = 10 log P/Pref
where P is the measured power in watts, and Pref is a reference power
in watts.
Recently it’s become common to use the decibel to refer to voltage
ratios as well:
dB = 20 log V/Vref
where V is the measured voltage, and Vref is a reference voltage.
This expression is mathematically equivalent to the previous one,
because power equals the square of the voltage divided by the circuit
resistance:
dB = 10 log P1/P2 = 10 log ((V21/R)/(V22/R))
= 10 log (V21/V22) = 20 log (V1/V2)
The resistance R (or impedance) in this equation is assumed to be
the same for both measurements, and thus divides out.
Signal level in decibels can be expressed in various ways, using
various units of measurement:
• dBm: decibels referenced to 1 milliwatt
• dBu or dBv: decibels referenced to 0.775 volt (dBu is preferred)
• dBV: decibels referenced to 1 volt
dBm
If you’re measuring signal power, the decibel unit to use is dBm,
expressed in the equation
dBm = 10 log P/Pref
where P is the measured power, and Pref is the reference power
(1 milliwatt).
For an example of signal power, use this equation to convert
0.01 watt to dBm:
dBm = 10 log (P/Pref)
= 10 log (0.01/0.01)
= 10
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Practical Recording Techniques
So, 0.01 watt is 10 dBm (10 decibels above 1 milliwatt).
Now convert 0.001 watt (1 milliwatt) into dBm:
dBm = 10 log (P/Pref)
= 10 log (0.001/0.001)
=0
So, 0 dBm = 1 milliwatt. This has a bearing on voltage measurement
as well. Any voltage across any resistance that results in 1 milliwatt is 0
dBm. This relationship can be expressed in the equation
0 dBm = V2/R = 1 milliwatt
where V = the voltage in volts, and R is the circuit resistance in ohms.
For example, 0.775 volt across 600 ohms is 0 dBm. One volt across
1000 ohms is 0 dBm. Each results in 1 milliwatt.
Some voltmeters are calibrated in dBm. The meter reading in dBm
is accurate only when you’re measuring across 600 ohms. For an accurate
dBm measurement, measure the voltage and circuit resistance, then
calculate:
dBm = 10 log ((V2/R)/0.001)
dBv or dBu
Another unit of measurement expressing the relationship of decibels
to voltage is dBv or dBu. This means decibels referenced to 0.775 volt.
This figure comes from 0 dBm, which equals 0.775 volt across 600 ohms
(because 600 ohms used to be a standard impedance for audio
connections):
dBu = 20 log V/Vref
where Vref is 0.775 volt.
dBV
Signal level also is measured in dBV (with a capital V), or decibels
referenced to 1 volt:
dBV = 20 log (V/Vref)
492
dB or not dB
A
where Vref is 1 volt. For example, use this equation to convert 1 millivolt
(0.001 volt) to dBV:
dBV = 20 log (V/Vref)
= 20 log (0.001/1)
= -60
So, 1 millivolt = -60 dBV (60 decibels below 1 volt). Now convert 1
volt to dBV:
dBV = 20 log (1/1)
=0
So, 1 volt = 0 dBV.
To convert dBV to voltage, use the formula
Volts = 10(dBV/20)
Change in Signal Level
Decibels also are used to measure the change in power or voltage across
a fixed resistance. The formula is
dB = 10 log (P1/P2)
or
dB = 20 log (V1/V2)
where P1 is the new power level, P2 is the old power level, V1 is the new
voltage level, and V2 is the old voltage level.
For example, if the voltage across a resistor is 0.01 volt, and it
changes to 1 volt, the change in dB is
dB = 20 log (V1/V2)
= 20 log (1/0.01)
= 40 dB
Doubling the power results in an increase of 3 dB; doubling the
voltage results in an increase of 6 dB.
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Practical Recording Techniques
The VU Meter, Zero VU, and Peak Indicators
A VU meter is a voltmeter of specified transient response, calibrated in
volume units or VU. It shows approximately the relative volume or
loudness of the measured audio signal. VU meters are used on analog
tape recorders, broadcast consoles, some live-sound mixing consoles, and
older recording consoles.
The VU-meter scale is divided into volume units, which are not necessarily the same as dB. The volume unit corresponds to the decibel only
when measuring a steady sine-wave tone. In other words, a change of
1 VU is the same as a change of 1 dB only when a steady tone is applied.
Most recording engineers use 0 VU to define a convenient “zero reference level” on the VU meter. When the meter on your mixer or recorder
reads “0” on a steady tone, your equipment is producing a certain level
at its output. Different types of equipment produce different levels when
the meter reads 0 (Figure A.2). Zero VU corresponds to:
• +8 dBm in older broadcast and telephone equipment
• +4 dBm in balanced recording equipment
• -10 dBV in unbalanced recording equipment
A 0 VU recording level (0 on the record level meter) is the normal
operating level of an analog tape recorder; it produces the desired
recorded flux on tape. A “0 VU recording level” does not mean a “0 VU
signal level.”
Figure A.2
494
VU-meter scale.
dB or not dB
A
With a VU meter, 0 VU corresponds to a recording level 8 dB below
the level that produces 3% third-harmonic distortion on tape at 400 Hz.
Distortion at 0 VU typically is below 1%.
The response of a VU meter is not fast enough to track rapid transients accurately. In addition, when a complex waveform is applied to a
VU meter, the meter reads less than the peak voltage of the waveform.
(This means you must allow for undisplayed peaks above 0 VU that use
up headroom.)
In contrast, a peak indicator responds quickly to peak program
levels, making it a more accurate indicator of recording levels. One type
of peak indicator is an LED that flashes on peak overloads. Another is
the LED bar graph meter commonly seen on digital recorders and some
mixers. Yet another is the PPM (peak program meter). It is calibrated in
dB, rather than VU. Unlike the VU meter reading, the PPM reading does
not correlate with perceived volume.
In a digital recorder, the meter is an LED or LCD bar graph meter
that reads up to 0 dBFS (Full Scale). In a 16-bit digital recorder, 0 dBFS
means all 16 bits are ON. In a 24-bit digital recorder, 0 dBFS means all 24
bits are ON. The OVER indication means that the input level exceeded
the voltage needed to produce 0 dBFS, and there is some short-duration
clipping of the output analog waveform. Some manufacturers calibrate
their meters so that 0 dBFS is less than 16 bits or 24 bits ON; this allows
a little headroom.
Balanced versus Unbalanced Equipment Levels
Generally, audio equipment with balanced (3-pin) connectors works at a
higher nominal line level than equipment with unbalanced (phono) connectors. There’s nothing inherent in balanced or unbalanced connections
that makes them operate at different levels; they’re just standardized at
different levels.
These are the nominal (normal) input and output levels for the two
types of equipment:
• Balanced: +4 dBu (1.23 volts)
• Unbalanced: -10 dBV (0.316 volt)
In other words, when a balanced-output recorder reads 0 VU on its
meter with a steady tone, it is producing 1.23 volts at its output connector. This voltage is called +4 dBu when referenced to 1 milliwatt. When
an unbalanced-output recorder reads 0 on its meter with a steady tone,
495
Practical Recording Techniques
it is usually producing 0.316 volt at its output connector. This voltage is
called -10 dBV when referenced to 1 volt.
Interfacing Balanced and
Unbalanced Equipment
There’s a difference of 11.8 dB between +4 dBu and -10 dBV. To find this,
convert both levels to voltages:
dB = 20 log (1.23/0.316)
=11.8
So, +4 dBu is 11.8 dB higher in voltage than -10 dBV (assuming the
resistances are the same).
A cable carrying a nominal +4 dBu signal has a signal-to-noise ratio
(S/N) 11.8 dB better than the same cable carrying a -10 dBV signal. This
is an advantage in environments with strong radio-frequency or hum
fields, such as in a computer. But in most studios with short cables, the
difference is negligible.
Connecting a +4 dBu output to a -10 dBV input might cause distortion if the signal peaks of the +4 equipment exceed the headroom of the
-10 equipment. If this happens, use a pad to attenuate the level 12 dB
(Figure A.3, top). The wiring shown converts from balanced to unbalanced as well as reducing the level 12 dB. If you hear hum with this
connection, add an isolation transformer as shown in Figure A.3 (bottom).
All the leads should be twisted.
You don’t always need that pad. Many pieces of equipment have a
+4/-10 level switch. Set the switch to the nominal level of the connected
equipment. If there is no such switch on either device, connect between
them a +4/-10 converter box such as the Ebtech Line Level Shifter
(www.ebtechaudio.com) or use the wiring shown here.
To connect an unbalanced -10 dBV output to a balanced +4 dBu
input, use the wiring shown in Figure A.4. All the exposed leads should
be twisted.
Microphone Sensitivity
Decibels are an important concern in another area: microphone sensitivity. A high-sensitivity mic puts out a stronger signal (higher voltage) than
496
dB or not dB
XLR-MALE OR TRS
TO ACTIVE BALANCED CROSS-COUPLED
DEVICE OUTPUT
2-CONDUCTOR
Tip/2 HI
SHIELDED CABLE
Ring/3
LO
Sleeve/1
4.7K
SLEEVE TIP
Shield
1.5K
not connected
at this end
SHIELD
TO ACTIVE PSEUDO-BALANCED
1-CONDUCTOR
DEVICE OUTPUT
SHIELDED CABLE
Tip/2 HI
1K
A
PHONE OR RCA PLUG
TO UNBALANCED
DEVICE INPUT
(plug shell
shown removed)
SLEEVE TIP
Ring/3
Sleeve/1
TO TRANSFORMER-BALANCED
DEVICE OUTPUT
Tip/2 HI
Ring/3
2-CONDUCTOR
SHIELDED CABLE
LO
Sleeve/1
Ring/3
2-CONDUCTOR
SHIELDED CABLE
SLEEVE TIP
1 : 1 TRANSFORMER
4.7K
LO
Sleeve/1
4.7K
Shield
1.5K
not connected
at this end
SHIELD
TO BALANCED
DEVICE OUTPUT
Tip/2
HI
1K
SHIELD
SHIELD
Shield
not connected
at this end
SHIELD
SLEEVE TIP
1.5K
Figure A.3 Top: Wiring balanced out to unbalanced in. The resistors form a
12-dB pad to match the balanced +4 dBu output to the unbalanced -10 dBV input.
Bottom: Same, with an isolation transformer added to reduce hum.
2-CONDUCTOR
SHIELDED CABLE
HI
TIP SLEEVE
PHONE OR RCA PLUG
TO UNBALANCED
DEVICE OUTPUT
(plug shell
shown removed)
LO
Shield
not connected
at this end
1 : 1 TRANSFORMER
2/Tip
1/Sleeve
XLR-MALE OR TRS
TO BALANCED
DEVICE INPUT
SHIELD
2-CONDUCTOR
SHIELDED CABLE
HI
TIP SLEEVE
OUT
3/Ring
Shield
not connected
at this end
2/Tip
3/Ring
LO
SHIELD
1/Sleeve
IN
Figure A.4 Top: Wiring unbalanced out to balanced in. Bottom: Same, with
an isolation transformer added to reduce hum.
497
Practical Recording Techniques
a low-sensitivity mic when both are exposed to the same sound pressure
level.
A microphone-sensitivity specification tells how much output (in
volts) a microphone produces for a certain input (in SPL). The standard
is millivolts per pascal, where one pascal (Pa) is 94 dB SPL.
A typical “open-circuit sensitivity” spec is 5.5 mV/Pa for a condenser mic and 1.8 mV/Pa for a dynamic mic. “Open-circuit” means that
the mic is unloaded (not connected to a load, or connected to a mic
preamp with a very high input impedance). If the spec is 5.5 mV/Pa, that
means the mic produces 5.5 mV when the SPL at the mic is 94 dB SPL.
If you put a microphone in a 20 dB louder soundfield, it produces
20 dB more signal voltage. For example, if 74 dBSPL in gives 0.18 mV out
(-75 dBV), then 94 dBSPL in gives 1.8 mV out (-55 dBV); 150 dBSPL in
gives 1.1 volt out (+1 dBV), which is approximately line level! That’s why
you need so much input padding when you record a kick drum or other
loud source.
498
B
OPTIMIZING YOUR
COMPUTER FOR
DIGITAL AUDIO
Once you’ve chosen some recording software and installed it, you’ll want
to make your computer run as fast and glitch-free as possible. Speed
becomes critical as you use more tracks, more effects, high bit rates and
high sampling rates.
The data flow of multitrack digital audio places high demands on
computer speed. Recording and playback of digital audio requires long,
continuous periods of streaming audio data. The more tracks in use, and
the higher the bit depth and sampling rate, the faster the data flow has
to be. And the more soft synths and effects plug-ins that are in use, the
greater the load on the CPU.
Clearly, you need a fast computer for multitrack recording. But you
also need to optimize its settings for best results. I will cover some ways
to speed up the data flow and to reduce the CPU usage. If you follow
these tips, you will have a faster system that handles more plug-ins and
more tracks at once. Also, when you play tracks or burn CDs, clicks and
drop-outs in the audio will be less likely.
Most of these tips apply to a PC computer. Mac advice is offered at
the end of this appendix in the section Optimizing MacIntosh for Audio.
499
Practical Recording Techniques
Disclaimer: Backup your system and data files first, then proceed at
your own risk. Neither I nor Focal Press will be responsible for damage
to your computer system or files from making these changes. If you are
not comfortable doing a particular tweak, don’t do it. However, I have
done all these adjustments with no problems, and they are reversible.
Speeding Up Your Hard Drive
The hard drive should have a fast average access time (under 9 msec) and
a high internal sustained transfer rate. Some recommended hard drives
are the Seagate Barracuda, Maxtor Diamond Max, and Western Digital
models.
What transfer rate is needed? The data rate of 24 tracks at 24-bits/
96 kHz is 6.6 MB/sec. That is a practical minimum.
The best current hard drives can transfer about 40 MB/sec continuously with a PCI bus and an Ultra ATA/66 or Ultra ATA/100 interface
(for EIDE drives), or a SCSI interface for SCSI drives. Do not use an ISA
bus interface—its rate tops out at 2 MB/sec. SCSI drives tend to be faster
than IDE, but SCSI costs more, and many IDE drives are fast enough.
To use ATA66 or higher, your motherboard and BIOS must support
it. You need an 80-pin ribbon cable that is 18 inches maximum. Plug the
blue connector into the motherboard, the black one into the Master
device, and the gray one into the Slave device.
Hard drives with high rotational speed or spindle rate (7200 rpm
or greater) tend to have faster transfer rate. They are recommended for
24-bit multitrack productions. The typical sustained transfer rate of a
7200 rpm drive is 30 to 40 MB/sec. This provides up to 160 16-bit/
44.1 kHz tracks or 50 24/96 tracks, depending on file fragmentation.
For fastest speed, use one hard drive for applications and Windows
files, and another for audio data. That way the audio drive head does
not waste time looking for system files. Put the Windows drive on
the Primary IDE channel as a master, and put the audio drive on the
Secondary IDE channel as a master. To set a drive to master or slave,
change the jumpers on the back of the drives. A laptop computer can
connect to an external USB or FireWire hard drive that is used just for
audio files.
You can put the two hard drives on the same IDE cable (both on the
Primary channel) as master and slave. Usually, but not always, they will
run a little slower that way. If you have a second CD-ROM drive, put it
on the secondary channel as a slave.
500
Optimizing Your Computer for Digital Audio
B
If you have only one hard drive, use one disk partition for audio
files and another partition for programs. That way you can defragment
or reformat the audio data partition frequently.
Defragment the audio file drive often. Defragging reorganizes files
into contiguous areas on the disk so that each audio file can be accessed
with minimum head movements. Before you defrag, disable programs in
the System Tray, then select Start > Run > Scandisk.exe (Win98) or
Chkdsk.exe (Win2000 and XP). Then select Start > Run > Defrag.exe.
When you are finished using all the files on the audio data drive,
reformat it to zero-out the clusters. This is necessary even if you deleted
all the files.
Your system will run faster if you delete unneeded applications.
Select Start > Settings > Control panel > Add/Remove programs. You
must uninstall a program, rather than deleting its folders, to notice an
improvement.
Install lots of RAM, at least 256 MB for audio, or at least 512 MB for
soft synths. How does more RAM help? When your DAW application is
streaming audio, it continuously feeds data into a RAM buffer for each
track. If the RAM buffer is big, it needs to be filled less often, so the diskdrive heads need to search less often. A larger RAM buffer lets the disk
heads work more efficiently by getting bigger continuous chunks of data
into RAM. Also, having lots of RAM prevents frequent access of the swap
file (described later). The goal is to have your programs running in RAM,
rather than swapping data to your hard drive.
Important: Use drivers that allow bus mastering. If necessary,
install bus-mastering drivers for your hard drives. To check for bus mastering in Windows, select Start > Settings > Control panel > System >
Hardware > Device manager > Hard disk controllers. Look for Bus master
controller.
Important: Check that Direct Memory Access (DMA) is activated on
hard drives and CD ROMs. DMA mode transfers data directly from the
hard drive to RAM, bypassing the CPU. With DMA, your CPU overhead
(while accessing the drive) will fall from about 50 to 5 percent or less.
Here is the procedure:
• In Windows 2000 and XP, select Start > Settings > Control Panel >
System > Hardware > Device Manager > IDE ATA/ATAPI Controllers (or hard disk controller) > Right-click Primary IDE channel
> Properties > Advanced Settings Tab > Transfer Mode: “DMA if
available.” Repeat for the Secondary IDE channel. Reboot.
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Practical Recording Techniques
• In Windows 98, select Start > Settings > Control Panel > System >
Device Manager > Disk drives > Right-click your hard drive >
Properties > Settings > Check “DMA” if it isn’t already. Reboot.
Two more tweaks: Select Start > Settings > Control panel > System
> Performance > File system > Hard disk. Set Read-ahead optimization
to minimum. Set Typical Role to Network Server because it gives higher
priority to disk use, and will provide more RAM to open programs faster.
You can also speed the data transfer of CD-ROM drives and CD
burners. Go to Start > Settings > Control panel > System > Device
manager, and double-click CD-ROM. Select your model of CD-ROM >
Properties > Settings. Check Disconnect, Sync data transfer, and DMA.
Disable write-behind caching on your hard drives: Write-behind
caching waits until the system is idle before writing data to the hard
drive, causing a delay. Here’s how to turn it off:
• In Win2000: Select My Computer > right-click a hard drive >
Properties > Hardware > Highlight a hard drive > Properties > Disk
properties > Uncheck “Write cache enabled” > OK. Do this for all
the IDE drives listed. Reboot.
• In XP: Select Start > Settings > Control Panel > System > Hardware
> Device Manager > Disk drives > Double click on your audio data
drive > Policies > Uncheck “Enable Write Caching” > OK. Reboot.
• In Win98: Select Start > Settings > Control Panel > System >
Performance > File System > Troubleshooting > Check “Disable
write-behind caching for all drives” > OK. Reboot.
Disable read-ahead optimization: In Win 98, select Start > Settings >
Control Panel > System > Performance > File System > Hard disk > Move
the read-ahead slider far left. In Win2000, select My Computer > Rightclick the drive you want to alter > Properties > Hardware > Properties >
Disk Properties > Move the read-ahead slider far left.
Increasing Processing Speed
A computer has a central processing unit (CPU) that does most of the calculations needed to run software. For example, in some DAWs the CPU
performs all the signal processing for real-time effects. Get a computer or
motherboard with the fastest CPU that you can afford—a clock speed of
2 Gigahertz or greater. Consider getting a computer or motherboard with
a multiprocessing CPU such as the AMD Athlon MP.
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Optimizing Your Computer for Digital Audio
B
The following tips reduce the amount of data that the CPU has to
handle:
Do not enable hyperthreading in BIOS unless your software requires
it.
If you hear drop-outs or glitches, maybe too many real-time
effects are running. Select a track that has real-time effects, and bounce
(export) that track with effects to an open track. That way the effects are
recorded or embedded in the bounced track, rather than running in real
time. This reduces CPU loading. Then archive (save) the original track
and delete it from the project. Muted audio tracks also put a load on
the CPU. Archive tracks that are muted, then delete those tracks from
the project.
Consider converting MIDI soft-synth tracks into audio tracks.
Do not insert the same delay effects (echo, reverb, chorus, flanging)
in several tracks. Instead, set up an aux bus that has the desired effect.
Use aux send controls on tracks to adjust the amount of effects on each
track. This reduces the number of effects processes that are running and
reduces CPU loading.
In extreme cases, consider installing a Digital Signal Processing
(DSP) card, such as the TC Works PowerCore. It handles the processing
for the plug-ins. The plug-ins access the card rather than the CPU. You
can install multiple cards to expand the system. Pro Tools includes its
own DSP cards.
Before recording, turn off the waveform drawing function of your
sound clips or regions.
Reduce the number of colors: Right-click the Desktop > Properties >
Settings > set Colors to 16 bit or 256 colors. A higher setting reduces
audio performance when the level meters redraw in your audio
application.
Reduce video acceleration: Select Start > Settings > Control panel >
System > Performance > Graphics > Advanced. Reduce Hardware
Acceleration as much as you can without degrading the display of your
audio program.
In Win2000 and XP, adjust visual effects for best performance: Select
Start > Settings > Control Panel > System > Advanced > Performance
Settings > Visual Effects Tab > Adjust for best performance.
Change the Performance mode for the operating system: Right-click
My Computer > Properties > Advanced > Performance > Settings > Select
Background Services. This setting allocates more processor time to background activities, such as streaming audio.
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Preventing Interruptions
Unnecessary background programs can rob CPU cycles, interrupt the
audio program, and interrupt the hard-drive head from playing audio.
The following tweaks to your PC can increase the number of tracks and
effects you can play without drop-outs or clicks by disabling various
background programs or increasing free memory.
Don’t multitask (run other programs) while the audio is streaming.
Each additional task slows down the system. Press Ctrl+Alt+Del to see
what’s running, highlight anything you don’t need, and select End Task.
Leave Explorer and Systray running. Don’t scroll while recording or
playing back.
Turn off autosave except when working just on MIDI files.
Use a PS/2 mouse instead of a USB mouse, which can cause audio
instability.
Switch off your Anti-Virus program when using your programs. Do
this by right clicking on the icon on the bottom right of your screen, then
click “Disable.” You need Anti Virus for downloading files from outside
sources but not for DAW work.
Check Interrupts (IRQs):
• Right click My Computer > Properties > Device Manager” > Doubleclick “Computer.” You will see a complete list of all the IRQs in use.
Make sure that SCSI controllers do not share interrupts with anything. Make sure the sound card has its own IRQ number. Do not
share audio cards/devices IRQs with USB, SCSI, or graphics cards.
Do not share Network/Modems IRQs with USB/SCSI/Video. Do
not assign IRQ #9 to anything; that is the cascaded IRQ from #2. To
reset IRQ’s, you might need to remove ALL cards except for the
video card and add one card at a time in different slots.
• Place your audio card in a non-IRQ-shared PCI slot. Look in the PCI
table of your motherboard manual for the highest-priority slot that
does not share with another device or another slot. Consider using
a shareware utility called PowerStrip, which lets you adjust PCI
latency timers. Set the latencies high enough to get the needed performance, and no higher.
• If you are not using any devices on your USB, serial or parallel ports,
go to the BIOS and disable them. This will reduce the number of
IRQs and may prevent conflicts. Also disable or disconnect other
devices that you are not using; this frees up interrupts.
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B
Disable CD-ROM autoplay (turn off Auto Insert Notification): In
Win XP, select Start > Run > type regedit > HKEY__LOCAL__MACHINE
> System > CurrentControlSet > Services > Cdrom. Set autorun to 0
instead of 1 at the right end of the displayed number. In Win 98, Rightclick My Computer and select Device Manager. Click on the + sign next
to the CD-ROM. Double-click a device. Then click Settings and uncheck
Auto Insert Notification. Repeat for other CD-ROMs.
Disable Background image: Right-click Desktop > Properties > Background > None.
Disable Screen Saver: Right-click Desktop > Properties > Screen
Saver > None.
Switch off power schemes: Start > Settings > Control Panel > Power
Options > Set “Turn off hard discs” to “Never.”
Switch off hibernation: Start > Settings > Control Panel > Power
Options > Hibernate > Uncheck “Enable hibernate support.”
Remove programs that load on startup: In Win98 and XP, select Start
> Run > Type in MSCONFIG and press OK. Select the “Startup” tab and
deselect everything but the system tray and the speaker volume control.
Press Apply, then OK. Reboot. For faster startup, archive fonts you don’t
use. They are in Windows\fonts or WinNT\fonts. You might want to
remove autoexec.bat and config.sys from the boot sequence. This
removes most DOS-compatibility mode drivers that can sap resources.
For Win2000, get “Startup Control Center” from www.download.com.
Disable virtual memory (also called a swap file or paging file): When
your system has used all its RAM, it saves and loads data to your hard
drive in a swap file.
This process can interrupt audio streaming. It’s best to install more
memory and disable the swap file. Here’s what to do:
• In Windows 2000 and XP: Select Start > Settings > Control Panel >
System > Advanced > Performance options > Advanced > Virtual
Memory > Change > Disable Virtual Memory > OK. Close the
windows and reboot.
• In Windows 98: Select Start > Control Panel > System > Performance
> Virtual memory > Disable Virtual Memory > OK. Close the
windows and reboot.
Disable System Sounds: This prevents interruptions caused by
Windows’ bells and chimes. It also may prevent audio conflicts due to
Windows sounds being at low sample rates and bit rates. Select Start >
Settings > Control Panel > Sounds and Audio Devices (or Sounds and
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Practical Recording Techniques
Multimedia) > Sounds tab > Set “Sound Scheme” to “No sounds . . .”
Press No to “Do you want to save the previous scheme?” Hit Apply.
In WinXP, disable unnecessary services: A service is a background
program. Some are necessary, but many are not. They consume memory
and resources. Select Start > Run > Type services.msc > Services. Doubleclick each service to read about it and set its status to “automatic,”
“manual,” or “disabled.” For advice on setting Services, go to
www.blkviper.com. When done, exit Services and reboot.
Setting the Buffer Size
When you play or record several tracks at once with real-time effects, or
record at a high sample rate, you might hear drop-outs or clicks in the
audio. Playback might stop. This is caused by too much data flow for the
CPU to handle, or by buffer memory being emptied faster than it can be
refilled.
In your recording software, increase the size of the buffer a little at
a time until the drop-outs or glitches stop. Ideally you’d do this just
during playback or mixdown, because enlarging the software buffer
increases latency (monitoring delay). If a small buffer setting causes problems during overdubs, temporarily disable any plug-ins.
In Windows XP, reduce your audio interface buffer size to 128 MB in
its software control panel. This reduces latency. Pro Tools might need a
buffer size of 256 or 512.
Other Tips
• Check
out
www.tweakXP.com,
www.Tweak3D.net,
and
www.extremetech.com.
• More information on computer recording can be found at
www.pcrecording.com.
• Three
vendors
of
audio-optimized
computers
are
www.dawbox.com, www.sweetwater.com (Creation Station), and
www.liquiddaw.com.
• Microsoft has a patch that fixes audio stuttering with USB devices
in XP. Go to www.microsoft.com and look for 307271.
• Go to the manufacturer Web sites of your sound card (or audio interface) and audio editing software. Check out the support sections for
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Optimizing Your Computer for Digital Audio
B
advice on optimizing your computer and on troubleshooting sound
problems.
• Keep your sound card(s) away from the AGP graphics card to
prevent hum.
• Don’t install much software (it can corrupt the registry).
• On the Web, download the latest drivers for your motherboard,
video card, IDE controller, CD burner, recording software, and
sound card or audio interface. Also download the Windows updates.
However, Windows XP Service Pack 2 is not recommended for most
audio software.
• Consider using an AGP video card rather than a PCI video card to
reduce the load on the PCI bus.
• Free up disk space by uninstalling Windows components that you
don’t use. Select Start > Settings > Control Panel > Add or remove
programs > Add/Remove Windows Components. For Win98, select
Start > Settings > Control Panel > Add or remove programs >
Windows Setup.
• For Win2000 and XP, disable Disc Indexing Service on NTFS formatted drives if you do NOT do frequent searches for filenames.
Double-click My Computer > Right-click each hard drive > Properties > Uncheck “Allow Indexing Service to index this disc for fast file
searching” > Apply. Choose all files and subfolders within the drive.
This action takes a while as all the files are scanned. If you get a
message that says Access Denied . . . , press “Ignore All.”
• Vcache is an amount of RAM that is set aside by Windows to store
data recently read from your hard drive that may be required again.
Go to Start > Run > and type Sysedit to open System.ini in a text
editor. Find [vcache]. Under [vcache], make sure MinFileCache and
MaxFileCache are both set to the same value. Use 4096 with 32 MB
of RAM installed; use 8192 with 64 MB, and use 16,000 with 128 MB
or more. Save System.ini and reboot. These settings can prevent
clicks and skipping audio.
• If you have a utility that measures disk thruput (sustained disk
transfer rate) you might want to measure your system’s speed before
and after each hard-drive change mentioned above. That way you
will know which changes were effective. A good utility is DskBench,
available free from www.prorec.com and other sources.
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Practical Recording Techniques
Optimizing MacIntosh for Audio
Many of the PC tips apply to Mac: Use a second, fast hard drive running
at 7200 rpm or higher for audio files. Use a minimum of non-audio software. Disable energy-saver or sleep software. Update drivers. Reduce
monitor resolution. Disable video acceleration software and cards. Check
online user groups for advice.
• Check the Memory panel and turn off virtual memory.
• Check for enough application memory. Select the program’s icon
and press Command-I. In the info window that appears, try increasing the amount of allotted memory.
• Minimize extensions. Extensions are small programs that extend the
functionality of the operating system when they are loaded. But they
use up CPU clock cycles and slightly reduce stability. You might
disable all extensions but these: sound card, Appearance, QuickTime, SystemAV, and video drivers. Consider loading the CD-ROM
driver only when you need it. If the recording application freezes
after boot-up, check the application’s documentation for known
extension conflicts.
• Upgrade to OS 8 or higher.
• Use a G4 or better, not an iMAC.
• Use HFS on the audio drive—not HFS+ (extended). HFS+ can make
the cluster sizes too small for efficient streaming of audio.
• Buy more RAM: 256 MB or more is recommended.
• Delete outtakes and unused files to prevent a “too many files open”
message.
• If you can’t play enough tracks, increase the buffer size.
• If you hear pops or clicks, check your sound card’s clock settings.
When recording an analog source, set it to Internal Clock or Sync. If
your source is digital, set it to external S/PDIF sync or the format
you are using. Be sure sample rates match. Move audio and digital
cables away from USB cables and power lines. Try turning off USB
hubs, modems and printers.
• If your system crashes frequently, try removing downloaded software. Delete your application’s preferences file if it has become
corrupt.
• If the application stops in the middle of a recording, check to see
whether you have set a maximum recording time in advance.
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C
INTRODUCTION TO SMPTE
TIME CODE
SMPTE time code is a special signal recorded on tape or hard disk that
can sync together two multitrack recorders so that they operate as one.
Time code can synchronize an audio recorder with a video recorder, or
sync audio clips with a video program in a window on a computer screen.
SMPTE stands for the Society of Motion Picture and Television
Engineers. The SMPTE standardized the time-code signal for use in video
production, and you can use it in audio recording as well. SMPTE time
code is something like a digital tape counter, where the counter time is
recorded as a signal on tape or hard disk.
How the Time Code Works
A time-code generator creates the time-code signal (a 1200-Hz modulated
square wave). You record—or stripe—this signal onto one track of both
recorders. A time-code reader reads the code off the two recorders. Then
a time-code synchronizer compares the codes from the two transports
and locks them together in time by varying the motor speed of one of the
transports.
The counter time is recorded as a signal on tape or hard disk. Pictures on a video screen are updated approximately 30 frames per second,
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Practical Recording Techniques
where a frame is a still picture made of 525 lines on the screen. 525
lines/30 frames is the format used only in the United States. SMPTE time
code assigns a unique number (address) to each video frame—8 digits
that specify hours:minutes:seconds:frames.
Each video frame is identified with its own time-code address; for
example, 01:26:13:07 means “1 hour, 26 minutes, 13 seconds, and 7
frames.” These addresses are recorded sequentially: for each successive
video frame, the time-code number increases by one frame count. There
are approximately 30 frames per second in the American TV system, so
the time code counts frames from 0 to 29 each second.
Time-Code Signal Details
The SMPTE time code is a data stream that is divided into code words.
Each code word includes 80 binary digits (or bits) that identify each video
frame (Figure C.1).
The 80-bit time-code word is synchronized to the start of each video
frame. The code uses binary 1’s and 0’s. During each half-cycle of
the square wave, the voltage may be constant (signifying a 0) or changing (signifying a 1). That is, a voltage transition in the middle of a halfcycle of the square wave equals a 1. No transition signifies a 0. This is
called biphase modulation (Figure C.2). It can be read forward or reverse,
at almost any tape speed. A time-code reader detects the binary 1’s and
0’s and converts them to decimal numbers to form the time-code
addresses.
SMPTE words also can include user information. There are 32
multipurpose bits (8 digits or 4 characters) reserved for the user’s data—
for example, the take number.
The last 16 bits in the word are a fixed number of 1’s and 0’s called
sync bits. These bits indicate the end of the time-code word, so that the
time-code reader can tell whether the code is being read forward or in
reverse.
Drop-Frame Mode
SMPTE code can run in various modes depending on the application.
One of these, Drop-Frame mode, is needed for specific reasons.
Black-and-white video runs at 30 frames per second. A time-code
signal also running at 30 frames per second will agree with the clock on
the wall. Color video, on the other hand, runs at 29.97 frames per second.
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Introduction to SMPTE Time Code
Figure C.1
C
An 80-bit time-code word.
Figure C.2
Biphase modulation used in SMPTE time code.
If a color program is clocked at 30 frames per second for 1 hour, the actual
show length will run 3.6 seconds (108 frames) longer than an hour.
The Drop-Frame mode causes the time code to count at a rate to
match the clock on the wall. Each minute, frame numbers 00 and 01 are
dropped, except every 10th minute. (Instead of seeing frames . . . 27, 28,
29, 00 on the counter; you see frames . . . 27, 28, 29, 02.) This speeds up
the time-code counter to match the rate of the video frames. The video
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Practical Recording Techniques
frames still progress at 29.97 frames per second, and the time code progresses at 30 frames per second, but it drops every few frames—so the
effective time-code frame rate is 29.97 frames per second.
You program the time-code generator to operate in Drop (DropFrame) or Non-Drop (Non-Drop-Frame) mode. Non-Drop can be used
for audio-only synchronizing, but Drop mode should be used if the audio
will be synced to a video tape later on.
Setting Up a Time-Code System
To use the SMPTE time code, you need a time-code generator, reader, and
synchronizer. These may be all-in-one or separate units. Figure C.3 shows
a typical system hookup, in which the generator, reader, and synchronizer are combined in one unit.
Set the generator to Time-of-Day code, or any other convenient starting time. If you are syncing to video, feed the generator a sync signal
from the video source being recorded. This will lock the generator
together in time with the video source. For audio-only applications, use
the internal crystal sync.
Select Drop-Frame or Non-Drop-Frame mode, and stay with it for
the entire production. Use Drop-Frame mode if you anticipate syncing
audio to video in the future.
Figure C.3
time code.
512
Typical hookup for synchronizing two tape transports with SMPTE
Introduction to SMPTE Time Code
C
Next, set the frame rate: 29.97, 30, 24, or 25 frames per second, using
the following guidelines:
• Color video productions require 29.97 frames per second.
• Black-and-white video or audio-only productions use 30 frames per
second.
• Film usually runs at 24 frames per second.
• European TV-using EBU (European Broadcast Union) time coderequires 25 frames per second.
The time-code signal appears at the generator output, which is a
standard 3-pin audio connector. Signal level is +4 dBm. The signal is fed
through a standard 2-conductor shielded audio cable. To avoid crosstalk
of time code into audio channels, separate the time-code cables from
audio cables. Patch the time-code signal into an outside track of the
recorders you want to lock together. Then, patch the outputs of those
time-code tracks to the inputs of the time-code reader.
The reader decodes the information recorded on tape or hard
disk and, in some models, displays the time-code data in the
hours:minutes:seconds frames format. Some readers have an error bypass
feature that corrects for missing data.
The time-code synchronizer matches bits between two time-code
signals to synchronize them. The synchronizer compares tape direction,
address, and phase to synchronize two SMPTE tracks via servo control
of the transport motors. The two tape machines to be synced are called
“master” and “slave.” The synchronizer controls the slave by making its
tape position and speed follow that of the master.
Connect the shielded multipin interface cable between the synchronizer and slave machine to control the slave’s tape transport and
motors. This interface cable has channels for controlling the capstan
motor, tape direction, shuttle modes, and tachometer (more on the tach
later).
Because the time-code signal becomes very high in frequency when
the tape is shuttled rapidly, special playback amplifier cards with
extended high-frequency response may be needed to reproduce the
SMPTE signal accurately. These cards are available from the recorder
manufacturer.
Unfortunately, when the tape is in shuttle mode (fast forward or
rewind), the tape usually is lifted from the heads—losing the SMPTE
signal. In this case, the recorders are synchronized using tach pulses from
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Practical Recording Techniques
the recorders as a replacement for the SMPTE time code. Some synchronizers are fed tach pulses from the slave only.
If chase mode is available, the slave follows the shuttle motions of
the master. If the master is put in fast-forward, the slave goes into fastforward, and so on. Without chase mode, the synchronizer notes the
address of the master tape when it is stopped and cues the slave to match
that location. Chase mode is useful for repetitive overdubs.
How to Use SMPTE Time Code
Suppose you want to synchronize two multitrack recorders. Follow this
procedure:
1. If you’re working with analog tape recorders, clean the heads and
the tape path.
2. Record the SMPTE time code on an outside track of both analog
recorders at -5 to -10 VU, leaving the adjacent track blank, if possible, to avoid time-code crosstalk. Don’t put high-transient sounds
(such as drums) on that adjacent track; they can cause sync problems in analog tape machines. You might record the time code on
two tracks, which reduces the potential for dropouts.
3. Start recording, or striping, the code about 20 seconds before the
music starts, and continue nonstop with no breaks in the signal.
Stripe the two tapes simultaneously. If that is not possible, you need
a time-code editor to correct or insert an offset.
4. During playback, manually cue the slave to approximately the same
point as the master tape, using time-code address information as a
reference.
5. Engage the synchronizer in Lock and Chase mode, and enable it.
6. Put both recorders in Play mode.
7. Adjust the slave’s tape speed to gradually reduce the error between
transports to less than one time-code frame.
With some synchronizers, this operation is automatic. You set the slave
tape to approximately the same point as the master tape. Then put
the master in Play. When the synchronizer detects master time code, it
sets the slave machine in Play mode and, in a few seconds, adjusts
the slave’s speed to synchronize the two recorders. This condition is
called locked up.
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Introduction to SMPTE Time Code
C
When you record on two synchronized transports, try not to split
stereo pairs between two tapes. The slight time differences between
machines can degrade stereo imaging. Keep all stereo pairs on the same
tape, copying them if necessary onto the other tape.
When synching audio to video, get a word-clock signal derived from
video sync, and also get time code from the video system.
Restriping Defective Code
You may encounter degraded or erased sections on a time-code track.
This lost code must be replaced with good code in proper sequence. If
you need to re-record (restripe) a defective SMPTE track, use the Jam Sync
mode on the time-code generator. This feature produces new code that
matches the original addresses and frame count.
For example, suppose the slave tape needs to be restriped. Follow
this procedure:
1. Patch the slave’s time-code track into the generator set to Jam Sync
mode.
2. Patch the generator output into the time-code track input on the
slave machine (or into another track).
3. Play the tape. The time-code reader built into the generator detects
a section of good code and initializes the generator with that
information.
4. Start recording the new, regenerated code over the bad data (or on
a new track).
Jam Sync also should be used when you copy a tape containing time
code. With Jam Sync in operation, the code is regenerated to create a clean
copy. This procedure is preferable to copying the time-code track directly
because each generation can distort the code signal.
Audio-for-Video SMPTE Applications
With the advent of music videos and other audio/video combinations,
there’s a widespread need to sync audio to video. Studios doing soundtrack work for film or video can use SMPTE time code to synchronize
sound and picture for overdubbing narration, dialog, lip-sync, music,
environmental sounds, or sound effects.
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Practical Recording Techniques
Synchronizing to Video
Running audio and video recordings in synchronization for TV audio
editing is a typical postproduction method. You can edit the audio and
video portions of a program independently even though they are locked
together in time.
When you sync audio and video, select Longitudinal Time Code
(LTC) or Vertical Interval Time Code (VITC). Longitudinal code records
along the length of an audio track on the video tape. Vertical Interval code
is combined with the video signal and is placed in the vertical blanking
interval—the black bar seen over the TV picture when it is rolling vertically. VITC frees up an audio track for other purposes.
If you record the time-code signal on an audio or cue track of the
video recording, do not use automatic level control because it may distort
the SMPTE waveform. Instead, adjust the time-code signal level
manually.
Some time-code systems include a character inserter that displays
the address on the video monitor. If desired, these addresses can be
recorded with (burned into) the picture—a feature called window dub.
The Audio-Tape Synchronization Procedure
At a typical on-location video shoot, the video from the camera(s) is
recorded on a videocassette recorder, while the audio from the microphones is recorded on a separate high-quality tape recorder (such as a
Nagra) or a portable DAT with SMPTE time-code capability. Both video
and audio tapes are prestriped with SMPTE time code so that they can
be synchronized later in postproduction.
Back at the studio, you connect the audio and video decks for
SMPTE sync as described earlier. When you play the video tape, the
SMPTE time code locks the picture and sound together. You can equalize the audio tape or change levels, and then lay it back (copy it) to the
video cassette.
If you sync video to a multitrack tape recorder, you can run the video
over and over as you refine the mix. Update your mix moves with an
automated mixer or automated mixing program. Finally, when the mix
is satisfactory, record the mixer output signal onto the video tape.
This procedure eliminates the dubbing step when transferring the
audio soundtrack to video tape. That is, you can mix the multitrack tape
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Introduction to SMPTE Time Code
C
master directly to the video tape (keeping sync), rather than mixing down
to 2-track and dubbing that to video tape.
Using SMPTE with a Digital Audio Workstation
SMPTE can be used with a Digital Audio Workstation (DAW). The
recording/editing software automates the playback of music and
sound-effects cues for motion-picture and video post-productions. Using
SMPTE time code, you can synchronize audio events, such as sound
effects, to film or video tape. Some popular programs for audio/video
work are Cakewalk Sonar Producer 4.0, BIAS Deck, MOTU Digital
Performer, Sonic Foundry’s Vegas Video, Avid Xpress Studio, and Adobe
Audition.
Either SMPTE or MIDI time code (MTC) keeps the soundtrack and
video in sync. MTC is a SMPTE signal sent on a MIDI cable. Using MIDI
time code, you can cue MIDI devices to play music and sound effects at
various SMPTE times relative to the video program.
You create a cue list (also known as an edit decision list or EDL) of
audio events, each with its own time-code address. These events are
played by MIDI instruments, or are played from recordings on a computer hard disk.
You record the video and audio onto hard disk. The video shows up
in a window on your computer screen. While watching the video, you
note the SMPTE times where you want sound effects or music to occur.
In this way you create the sound track and sync it to video, all in your
computer. Then dump the edited soundtrack to a prestriped videocassette or DVD.
This process can go through various steps.
1. First, you’re handed a work tape or DVD, which is a video recording of the program you’re working on. It has SMPTE time code
already striped on the DVD, and the SMPTE time code appears in a
window on-screen called a window dub. As stated before, some programs let you copy the video onto your hard disk.
2. Watch the picture. Using a MIDI keyboard workstation or your
DAW, compose and record musical parts related to the video scenes
and their SMPTE start/stop times. These times indicate how long
the music needs to be for each musical segment.
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Practical Recording Techniques
3. Dialog and wild sound are often recorded on a portable 2-track
recorder with a center track for time code. (Wild sound is ambient
noise recorded on the set while shooting, not synced with the video.)
Sync the dialog tape to the video.
4. Missing or poorly recorded dialog is replaced during a process
called looping or automatic dialog replacement (ADR). Have actors
watch the video and lip-sync their lines using the DAW.
5. Record sound effects so that they line up with corresponding events
in the video. Audition several sound effects from CD libraries,
pick the ones you like, and import them into tracks in the digital
audio workstation.
6. Using slow motion or freeze frame, go through the video and note
the SMPTE times where each sound effect should occur. You also can
nudge audio clips in time to align with video events.
DAW Features
The following are some of the many tasks that are offered in some DAWs:
• Spot and lay back sound effects (turn them on at the proper times
and record them onto the video tape).
• Do an automated mix.
• Back time events.
• Repeat events.
• Name events.
• Print cue lists, libraries, and recording logs.
• Map keyboards (show each effect’s location on a piano-style
keyboard).
• Cut/copy/paste, insert, and delete events.
• Enter cue locations by tapping on the space bar as the program
progresses.
• Display sound-effect cues graphically along with the music.
• Convert sequencer files to a cue sheet (hit list).
• Indicate both SMPTE time code and bar/beat for each event.
• Expand or compress the duration of a soundtrack.
• Enter subtle tempo variations, or introduce time offsets, to make
cues fall exactly on the beat.
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Introduction to SMPTE Time Code
C
• Write standard MIDI files with meter, beat, tempo, and event data
for use in a sequencer.
• Lock to MTC and SMPTE.
You also can perform various other tasks found in sequencer programs, such as quantization, tap-in tempo, and so on.
Other Time-Code Applications
SMPTE time code allows video editing under computer control. In
editing a video program, you copy program segments from two or more
video recordings onto a third recorder. On a computer you specify the
edit points (time-code addresses) where you want to switch from one
video source to another. You can rehearse edits as often as required.
Time code is used also as an index for locating cue points in a recording. During a mixdown, you can use these cue points to indicate where
to make changes in the mix.
Time code also can be used as a reference for console automation
and MIDI instruments. With this latter application, MIDI synthesizers can
be cued to any point within a sequence, rather than having to start at the
beginning.
By using SMPTE time code to lock together audio or video programs, you can greatly expand your operating flexibility.
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D
FURTHER EDUCATION
The following books, magazines, and literature are recommended to
anyone who wants more education in recording technology.
Books and Videos
The Library
Go to your local library and search their database for books on recording, home recording, music recording, audio recording, MIDI, or sound
production. Read everything you can on the subject.
Pro Audio Books
This company offers an online catalog of all sorts of audio and recording
books, videos and courses at www.proaudiobooks.com.
Music Books Plus
This is a catalog with a huge number of audio and recording books. The
Web site is www.musicbooksplus.com.
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Practical Recording Techniques
Focal Press
This is another major audio/recording books catalog and it is found at
http://books.elsevier.com/focalbooks/. For a detailed explanation of
stereo theory and stereo mic techniques, search the catalog for On Location Recording Techniques by Bruce Bartlett, published by Focal Press.
Amazon.com
This online bookstore has a great search engine. In the search field, type
in whatever audio subject you are interested in: DVD, MIDI, digital
audio, recording, mixing, microphones, etc.
Recording Magazines
Recording (home and project studio recording), www.recordingmag.com.
Mix (pro recording and concert sound), www.mixonline.com.
EQ (home, project, and pro recording), www.eqmag.com.
EQ also offers a recording and sound buyer’s guide.
Electronic Musician (home and project studio recording), www.
emusician.com.
Electronic Musician offers a supplement called “Desktop Music
Production Guide.”
Tape Op (home and project studio creative recording),
www.tapeop.com.
Sound On Sound (Britain’s premier recording publication),
www.soundonsound.com.
In those magazines are ads related to recording products and
services.
Pro Audio Magazines
Journal of the Audio Engineering Society (JAES; pro audio engineering.
Scholarly. With its journal, conventions, workshops and local chapters, the Audio Engineering Society is a tremendous resource,
www.aes.org.
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Further Education
D
Pro Audio Review (reviews of pro audio equipment), www.proaudioreview.com.
Live Sound (concert sound reinforcement), www.livesoundint.com.
Church Production (audio for houses of worship), www.churchproduction.com.
Technologies for Worship (audio for houses of worship),
www.tfwm.com.
Consumer Audio Magazines
Sound and Vision (consumer audio and video), www.soundandvisionmag.com.
Stereophile (high-end audio), www.stereophile.com.
The Absolute Sound (high-end audio), www.theabsolutesound.com.
Guides, Brochures, and Other Literature
Microphone application guides are available from
Crown International, www.crownaudio.com.
Shure Inc., www.shure.com.
Countryman Associates Inc., www.countryman.com.
AKG Acoustics Inc., www.akg.com.
Sennheiser Electronic Corp., www.sennheiserusa.com.
Audio-Technica U.S. Inc., www.audiotechnica.com.
Neumann/USA, www.neumannusa.com.
Schoeps Mikrofone, www.schoeps.de.
You can find valuable information in user manuals and free
sales literature provided by manufacturers of recording equipment.
Ask your equipment dealer for manufacturers’ phone numbers and Web
site URLs.
Guides to Recording Schools
The Audio Engineering Society offers a directory of educational programs
at www.aes.org/education/directory.cfm.
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Practical Recording Techniques
Each July issue of Mix magazine contains a comprehensive directory
of recording schools, seminars, and programs. Universities and colleges
in most major cities have recording-engineering courses.
An index of recording schools is at www.modrec.com/schools/
The Internet
A great place to ask questions, besides magazines, is on the Internet. In
Google, select Groups, then type in rec.audio.pro. You can ask questions
and get answers from pro engineers. You may get conflicting answers,
because often there are many ways to do the same thing. Also, some who
reply are more expert than others. But you’ll often find stimulating
debates.
Some other valuable Web sites are www.homerecording.com,
www.prorec.com, www.kvraudio.com, www.recording.org, www.
vintagesynth.com, www.allmusic.com, www.microphones.com, www.
digido.com, www.prosoundweb.com, www.digifreq.com, www.cdrfaq.
org/, www.harmony-central.com/recording, www.musicplayer.com
(forums), www.recordingconnection.com, www.popeye-x.com/tech/
xbert.htm, www.audio-recording-center.com, and www.josephson.com/
mic-faq.html.
Also see pcrecording.com, audiogrid.com, digitalprosound.com,
dvdforum.org, superaudiocd.com/, artofthemix.org, recordproduction.
com/, audiodirectory.nl/, binaural.com, artistpro.com, sweetwater.com
(check out Publications and Forums), tweakheads.com/ how_to_
research_studio_gear.html,
http://dir.yahoo.com/Entertainment/
Music/Recording/, and www.solorb.com/dat-heads/.
If you lack good multitrack recordings with which to practice
mixing, go to www.raw-tracks.com. There you can download individual
tracks in wav or mp3 format, or purchase a CD of raw tracks.
Some online MIDI resources are: midi.com, midiworld.com, ultimatemidi.com/, harmony-central.com/midi, borg.com/~jglatt/tutr/
miditutr.htm, cakewalk.com/tips/desktop.asp, and atarimagazines.
com/v7n2/MIDIResources.html.
The Web sites of audio equipment manufacturers have support sections, online discussion groups, and FAQs with lots of information.
Search for the name and model number of equipment you have, or are
interested in.
Do a Google search with the keywords audio, recording, recording
vocals, audio recording links, DAT, digital audio, and so on. Also search
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Further Education
D
for FAQs on various audio topics. You’ll discover hundreds of audiorelated websites and links. In Google, you can search Groups as well as
Web sites.
Recording Equipment Catalogs
Here are but a few catalogs from which to order recording gear:
American Musical Supply, www.americanmusical.com.
BSW, www.bswusa.com.
Guitar Center, www.guitarcenter.com.
Musician’s Friend, www.musiciansfriend.com.
Sam Ash, www.samash.com.
Sweetwater Sound, www.sweetwater.com.
The Woodwind and the Brasswind, www.wwandbw.com.
Experience
It’s the best teacher. Record all you can with any equipment you have.
You can buy a 4-track cassette recorder on ebay for $45, or download free
multitrack recording software. Then buy a cheap mic, and practice mic
techniques and overdubbing.
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E
IMPEDANCE
Impedance is one of audio’s more confusing concepts. To clarify this
topic, I’ll present a few questions and answers about impedance.
What Is Impedance?
Impedance (Z) is the resistance of a circuit to alternating current, such as
an audio signal. Technically, impedance is the total opposition (including
resistance and reactance) that a circuit has to passing alternating current.
A high-impedance circuit tends to have high voltage and low
current. A low-impedance circuit tends to have relatively low voltage and
high current.
I’m Connecting Two Audio Devices. Is It
Important to Match Their Impedances? What If
I Don’t?
First some definitions. When you connect two devices, one is the source
and one is the load. The source is the device that puts out a signal. The
load is the device you are feeding the signal into. The source has a certain
output impedance, and the load has a certain input impedance.
A few decades ago in the vacuum-tube era, it was important to
match the output impedance of the source to the input impedance of the
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Practical Recording Techniques
load. Usually the source and load impedances were both 600 ohms. If the
source impedance equals the load impedance, this is called “matching”
impedances. It results in maximum power transfer from the source to the
load.
In contrast, suppose the source is low Z and the load is high Z. If
the load impedance is 10 times or more the source impedance, it is called
a “bridging” impedance. Bridging results in maximum voltage transfer
from the source to the load. Today, nearly all devices are connected
bridging—low-Z out to high-Z in—because we want the most voltage
transferred between components.
If you connect a low-Z source to a high-Z load, there is no distortion or frequency-response change caused by this connection. But if you
connect a high-Z source to a low-Z load, you might get distortion or
altered response. For example, suppose you connect an electric bass
guitar (a high-Z device) into an XLR-type mic input (a low-Z load). The
low frequencies in the signal will roll off, so the bass will sound thin. And
the highs might roll off, making the sound dull.
We want the bass guitar to be loaded by a high impedance, and we
want the mic input to be fed by a low-impedance signal. A direct box or
impedance-matching adapter does this (Figure E.1). Such adapters are
available from Radio Shack.
The adapter is a tube with a phone jack on one end and a male XLR
connector on the other. Inside the tube is a transformer. Its primary
winding is high Z, wired to the phone jack. The transformer’s secondary
winding is low Z, wired to the XLR. You plug the guitar cord into the
phone jack, and plug the XLR into a mic input in a snake or mixer. Use
it with a bass guitar, electric guitar, or synth.
This impedance-matching adapter works, but is not ideal. The load
it presents to the bass guitar might be 12 kilohms, which will slightly load
down the high-Z guitar pickup, causing thin bass.
Figure E.1
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High-to-low impedance matching adapter.
E
Impedance
An active direct box solves this problem. In place of a transformer,
the active DI usually has a field effect transistor (FET). The FET has a very
high input impedance that does not load down the bass guitar.
What About Microphone Impedance?
Recording-quality mics have XLR (3-pin) connectors and are low Z (150
to 300 ohms). A low-Z mic can be used with hundreds of feet of cable
without picking up hum or losing high frequencies.
I’m Connecting a Mic to a Mixer. Is Impedance
a Consideration?
Yes. If your mixer has phone-jack inputs, they are probably high Z. But
most mics are low Z. When you plug a low-Z mic into a high-Z input you
get a weak signal. That’s because a high-Z mic input is designed to
receive a relatively high voltage from a high-Z mic, and so the input is
designed to have low gain. So you don’t get much signal amplification.
If you can’t get enough level when you plug a mic into a phone-jack
input, here’s a solution: Between the mic cable and the input jack, connect
an impedance matching adapter (Figure E.2). It steps up the voltage of
the mic, giving it a stronger signal.
The adapter is a tube with a female XLR input and a phone-plug
output. Inside the tube is a transformer. Its primary winding is low Z,
wired to the XLR. It secondary winding is high Z, wired to the phone
plug. Connect the mic to the XLR; connect the phone plug to the mixer’s
phone jack. Then the mixer will receive a strong signal from the mic.
If you’re using a phantom-powered condenser mic, the connections
are different. First, turn off any phantom power in your recorder-mixer.
Figure E.2
Low-to-high impedance matching adapter.
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Practical Recording Techniques
Connect your mic to a standalone phantom-power supply, and connect
the supply output to the impedance-matching adapter.
If your mixer has XLR inputs, they are low-Z balanced. In this case,
simply connect the mic to the mixer using a mic cable with a female XLR
on the mic end and a male XLR on the mixer end. A low-Z mic input is
typically about 1500 ohms, so it provides a bridging load to a mic that is
150 to 300 ohms.
Should I Consider Impedance When I Connect
Two Line-Level Devices?
This is seldom a problem. In most audio devices, the impedance of the
line output is low—about 100 to 1000 ohms. The impedance of the line
input is high—about 10 kilohms to 1 megohm. So every connection is
bridging, and you get maximum voltage transfer. Some audio devices,
such as passive equalizers, require a terminating resistor at the input or
output for best performance.
Can I Connect One Source to Two or
More Loads?
Usually yes. You can connect several devices in parallel across one line
output. Suppose you connect a mixer output simultaneously to a recorder
input, an amplifier input, and another mixer’s input in parallel. The combined input impedance of those three loads might be 4000 ohms, which
still presents a bridging load to the mixer’s 100-ohm output impedance.
Mics are a different story. If you connect one mic to two or more
mixers with a Y cable, the combined input impedance will be about
700 ohms or less. This can load down some microphones, reducing the
bass in dynamic mics or causing distortion in condenser mics. One solution is to use a transformer mic splitter.
Can I Connect Two or More Sources to
One Input?
Not recommended. If you combine two or more sources into a single load,
the low-output impedance of one source will load down the output of
the other source, and vice versa. This can cause level loss and distortion.
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Impedance
E
If you want to combine the signals from two devices into one input,
you need to put a series resistor in line with each device before combining them. That prevents each device from loading down the other. A
minimum resistor value might be 470 ohms per source. If the source is
balanced, use one resistor on pin 2 and one on pin 3—two resistors per
source.
Summary
• Impedance (Z) is the opposition to alternating current, measured in
ohms.
• Microphones and line outputs are usually low Z.
• Electric guitars, synthesizers, and line inputs are usually high Z.
• XLR mic inputs are low impedance; phone jack mic inputs are high
impedance.
• Speakers are usually 4 to 8 ohms.
• Equal impedances in parallel result in half the impedance.
• Equal impedances in series result in twice the impedance.
• Connect low-Z sources to low-Z inputs. (A low-Z input is usually 7
to 10 times the source impedance, but it’s still called a low-Z input.)
• Connect high-Z sources to high-Z inputs.
• Connect a low-Z source to a high-Z input through a step-up transformer (impedance matching adapter).
• Connect a high-Z source to a low-Z input through a step-down
transformer (impedance matching adapter, or direct box).
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GLOSSARY
A WEIGHTING See Weighted.
AAC (Advanced Audio Codec) A relatively new compressed audio file
format, AAC offers better sound quality than MP3, but with less storage
space and bandwidth. It’s also used with Digital Rights Management
technology to help control the copying and distributing of music.
A-B A listening comparison between two audio programs, or between
two components playing the same program, performed by switching
immediately from one to the other. The levels of the two signals are
matched. See also Spaced-Pair.
AC-3 Same as Dolby Digital, a perceptual encoding scheme that datareduces the six surround channels of a 5.1 system to two channels.
ACCENT MICROPHONE See Spot Microphone.
ACCESS JACKS See Insert Jacks.
ACTIVE COMBINING NETWORK A combining network with gain.
See Combining Network.
AES Audio Engineering Society.
AES/EBU Also called IEC 988 Type 1. An interface format for digital
signals, using a balanced 110 ohm mic cable terminated with XLR-type
connectors. See also S/PDIF.
AIFF (Audio Interchange File Format) A standard Mac format for
uncompressed digital audio files.
ALIGNMENT The adjustment of tape-head azimuth and of taperecorder circuitry to achieve optimum performance from the particular
type of tape being used.
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Practical Recording Techniques
ALIGNMENT TAPE A prerecorded tape with calibrated tones for
alignment of a tape recorder.
AMBIENCE Room acoustics, early reflections, and reverberation. Also,
the audible sense of a room or environment surrounding a recorded
instrument.
AMBIENCE MICROPHONE A microphone placed relatively far from
its sound source to pick up ambience.
AMPLITUDE, PEAK On a graph of a sound wave, the sound pressure
of the waveform peak. On a graph of an electrical signal, the voltage of
the waveform peak. The amplitude of a sound wave or signal as measured on a meter is 0.707 times the peak amplitude.
ANALOG-TO-DIGITAL (A/D) CONVERTER A circuit that converts
an analog audio signal into a stream of digital data (bitstream).
ANTI-ALIAS FILTER In an A/D converter, a lowpass filter that
removes all frequencies above 20 kHz before sampling in order to prevent
audio artifacts called aliasing.
ANTI-IMAGING FILTER In a D/A converter, a lowpass filter that
smooths the voltage steps in the analog signal that was generated by
translating digital numbers into analog voltages. The anti-imaging filter
recovers the waveform of the original analog signal.
ASIO (Audio Stream Input/Output) Steinberg’s computer audio
driver spec for Mac and Windows. ASIO has low latency because it interfaces directly between a sound card and the audio application software.
ASSIGN To route or send an audio signal to one or more selected
channels.
ATRAC (Adaptive Transform Acoustic Coding) A data compression
scheme (used in the MiniDisc) that reduces by 5 : 1 the storage needed for
digital audio. ATRAC is a perceptual coding method that omits data
deemed inaudible due to masking.
ATTACK The beginning of a note. The first portion of a note’s envelope
in which a note rises from silence to its maximum volume.
ATTACK TIME In a compressor, the time it takes for gain reduction to
occur in response to a musical attack.
ATTENUATE
534
To reduce the level of a signal.
Glossary
ATTENUATOR In a mixer (or mixing console) input module, an
adjustable resistive network that reduces the microphone signal level to
prevent overloading of the input transformer and mic preamplifier.
AUDIO INTERFACE A device that connects to a computer and converts an audio signal into computer data for storage in memory or on
hard disk. The interface also converts computer data into an audio signal.
See Breakout Box, I/O Box, and Sound Card.
AUTOLOCATE A recorder function that makes the tape or disk go to
a program address (counter time) at the press of a button.
AUTOMATED MIXING A system of mixing in which a computer
remembers and updates mixer control settings and moves. With this
system, a mix can be performed and refined in several stages and played
back at a later date exactly as set up previously.
AUXILIARY BUS (AUX BUS) A bus or channel that contains a mix of
the aux-send signals of the input modules in a mixer. An aux bus is used
to send signals to an effects unit or monitor system. See Effects Bus.
AUXILIARY SEND (AUX-SEND) A control in a mixer’s input module
used to send that module’s signal to an aux bus. The aux-send level
adjusts the amount of effects heard on an instrument, or adjusts the loudness of that instrument in the monitor system.
A/V DRIVE A hard-disk drive meant for audio/video use. It postpones
thermal recalibration until the disk is inactive, preventing data errors.
AZIMUTH In a tape recorder, the angular relationship between the
head gap and the tape path.
AZIMUTH ALIGNMENT The mechanical adjustment of the record or
playback head to bring it into proper alignment (90 degrees) with the tape
path.
BACK-TIMING A technique of cueing up the musical background or
a sound effect to a narration track so that the music or effect ends simultaneously with the narration.
BAFFLED-OMNI A stereo miking arrangement that uses two earspaced omnidirectional microphones separated by a hard padded baffle.
BALANCE
The relative volume levels of various tracks or instruments.
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Practical Recording Techniques
BALANCED AC POWER AC power from a center-tapped power
transformer. Instead of one 120 V line and one 0 V line, it has two 60 V
lines. They are in phase with each other and sum to 120 V. But they are
connected to the center-tap ground out of phase (one is +60 V; the other
is -60 V). Any hum and noise on the grounding system cancel out.
BALANCED LINE A cable with two conductors surrounded by a
shield, in which each conductor is at equal impedance to ground. With
respect to ground, the conductors are at equal potential but opposite
polarity; the signal flows through both conductors.
BANDPASS FILTER In a crossover, a filter that passes a band or range
of frequencies but sharply attenuates or rejects frequencies outside the
band.
BASIC TRACKS Recorded tracks of rhythm instruments (bass, guitar,
drums, and sometimes keyboard).
BASS MANAGEMENT A subwoofer/satellite crossover, usually part
of a surround receiver. Bass management routes frequencies above about
100 Hz to the five full-range speakers, and routes frequencies below about
100 Hz from all six channels to the subwoofer. It affects only what you
monitor, not what goes on tape. Bass management can be done by a
surround-receiver circuit, a standalone box, a special circuit in a subwoofer, or a software plug-in.
BASS TRAP An assembly that absorbs low-frequency sound waves in
the studio.
BI-AMPLIFICATION (BI-AMPING) Driving a woofer and tweeter
with separate power amplifiers. An active crossover is connected ahead
of these power amplifiers.
BIAS In tape-recorder electronics, an ultrasonic signal that drives the
erase head. This signal is also mixed with the audio signal applied to the
record head to reduce distortion.
BIDIRECTIONAL MICROPHONE A microphone that is most sensitive to sounds arriving from two directions-in front of and behind the
microphone. It rejects sounds approaching either side of the microphone.
Sometimes called a cosine or figure-eight microphone because of the
shape of its polar pattern.
BINAURAL RECORDING A 2-channel recording made with an omnidirectional microphone mounted near each ear of a human or a dummy
536
Glossary
head, for playback over headphones. The object is to duplicate the
acoustic signal appearing at each ear.
BIT DEPTH (word length) The number of bits (ones and zeros) making
up a word in a digital signal (such as 16- or 24-bits). Each word is a binary
number that is the value of each sample. A sample is a measurement of
an analog waveform that is done several thousand times a second during
analog-to-digital conversion. High bit depth = long word length = high
resolution of the analog signal amplitude = high sound quality.
BLUMLEIN ARRAY A stereo microphone technique in which two
coincident bidirectional microphones are angled 90 degrees apart (45
degrees to the left and right of center).
BOARD
See Mixing Console.
BOUNCING TRACKS A process in which two or more tracks are
mixed, and the mixed tracks are recorded on an unused track or tracks.
Then the original tracks can be erased, which frees them up for recording more instruments.
BOUNDARY MICROPHONE A microphone designed to be used on a
boundary (a hard reflective surface). The microphone capsule is mounted
very close to the boundary so that direct and reflected sounds arrive at
the microphone diaphragm in phase (or nearly so) for all frequencies in
the audible band.
BREAKOUT BOX (I/O BOX) A group of audio input and output connectors in a chassis, which is wired to a sound card, a USB port, or a
FireWire port in a computer. Used to interface analog audio signals (and
often MIDI and digital signals) with a computer.
BREATHING The unwanted audible rise and fall of background noise
that may occur with a compressor. Also called pumping.
BULK TAPE ERASER A large electromagnet used to erase a whole reel
of recording tape at once.
BUS A common connection of many different signals. An output of a
mixer or submixer. A channel that feeds a tape track, signal processor, or
power amplifier.
BUS IN An input to a program bus, usually used for effects returns.
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Practical Recording Techniques
BUS MASTER In the output section of a mixing console, a potentiometer (fader or volume control) that controls the output level of a bus.
Also called Group Fader.
BUS OUT The output connector of a bus.
BUS TRIM A control in the output section of a mixing console that provides variable gain control of a bus, used in addition to the bus master
for fine adjustment.
BUZZ An unwanted edgy tone that sometimes accompanies audio,
containing high harmonics of 60 Hz.
CALIBRATION See Alignment.
CAPACITOR An electronic component that stores an electric charge. It
is formed of two conductive plates separated by an insulator called a
dielectric. A capacitor passes AC but blocks DC.
CAPACITOR MICROPHONE See Condenser Microphone.
CAPSTAN In a tape-recorder transport, a rotating post that contacts the
tape (along with the pinch roller) and pulls the tape past the heads at a
constant speed during recording and playback.
CARDIOID MICROPHONE A unidirectional microphone with side
attenuation of 6 dB and maximum rejection of sound at the rear of the
microphone (180 degrees off-axis). A microphone with a heart-shaped
directional pattern.
CD See Compact Disc.
CD-R (CD-Recordable) A recordable compact disc that cannot be
rewritten. Once recorded, it cannot be erased and reused.
CD-ROM A computer disk drive that plays computer data from CDROM disks. The disks are read optically by a laser, as in a compact disc
player.
CD-RW (CD-Rewritable) A recordable compact disc that can be rewritten. Once recorded it can be erased and reused.
CHANNEL A single path of an audio signal. Usually, each channel contains a different signal.
CHANNEL ASSIGN
538
See Assign.
Glossary
CHORUS 1. A special effect in which a signal is delayed by 15 to
35 msec, the delayed signal is combined with the original signal, and the
delay is varied randomly or periodically. This creates a wavy, shimmering effect. 2. The main portion of a song that is repeated several times
throughout the song with the same lyrics.
CLEAN
Free of noise, distortion, overhang, leakage. Not muddy.
CLEAR Easy to hear, easy to differentiate. Reproduced with sufficient
high frequencies.
CLIP See Region.
COINCIDENT-PAIR A stereo microphone, or two separate microphones, placed so that the microphone diaphragms occupy approximately the same point in space. They are angled apart and mounted one
directly above the other.
COMB-FILTER EFFECT The frequency response caused by combining
a sound with its delayed replica. The frequency response has a series of
peaks and dips caused by phase interference. The peaks and dips resemble the teeth of a comb.
COMBINING AMPLIFIER An amplifier at which the outputs of two
or more signal paths are mixed together to feed a single track of a tape
recorder.
COMBINING NETWORK A resistive network at which the outputs of
two or more signal paths are mixed together to feed a single track of a
tape recorder.
COMPACT DISC (CD) A read-only optical disc medium for storing
digital audio programs up to 74 minutes long. The compact disc stores
data in the form of a spiral groove of microscopic pits and is read optically by a laser. CD’s digital audio format is 44.1 kHz sampling rate and
16-bit word length.
COMPLEX WAVE
A wave with more than one frequency component.
COMPING Recording several musical performances (takes) of a single
instrument or vocal on different tracks, and selecting the best parts of
each take to be played in order on a composite track during mixdown.
COMPOSITE TRACK A track containing the best parts of several takes
of a musical-instrument or vocal performance.
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Practical Recording Techniques
COMPRESSION 1. The portion of a sound wave in which air molecules are pushed together, forming a region with higher-than-normal
atmospheric pressure. 2. In signal processing, the reduction in dynamic
range or gain caused by a compressor. 3. Data compression or data reduction is an encoding scheme to reduce the size of a data file by throwing
away audio data deemed inaudible because of masking. ATRAC, MP3,
MLP, AAC, RealAudio, OGG, and Microsoft Media are examples of compressed data formats.
COMPRESSION RATIO (SLOPE) In a compressor, the ratio of the
change in input level (in dB) to the change in output level (in dB). For
example, a 2 : 1 ratio means that for every 2 dB change in input level, the
output level changes 1 dB.
COMPRESSOR A signal processor that reduces dynamic range or gain
by means of automatic volume control. An amplifier whose gain
decreases as the input signal level increases above a preset point.
CONDENSER MICROPHONE A microphone that works on the principle of variable capacitance to generate an electrical signal. The microphone diaphragm and an adjacent metallic disk (called a backplate) are
charged to form two plates of a capacitor. Incoming sound waves vibrate
the diaphragm, varying its spacing to the backplate, which varies the
capacitance, which in turn varies the voltage between the diaphragm and
backplate.
CONNECTOR A device that makes electrical contact between a signalcarrying cable and an electronic device, or between two cables. A device
used to connect or hold together a cable and an electronic component so
that a signal can flow from one to the other.
CONSOLE See Mixing Console.
CONTACT PICKUP A transducer that contacts a musical instrument
and converts its mechanical vibrations into a corresponding electrical
signal.
CONTROL ROOM The room in which the engineer controls and monitors the recording. It houses most of the recording hardware.
CONTROLLER SURFACE A chassis with faders (and sometimes
buttons and knobs) that resembles a mixer, used to adjust virtual controls
that appear on-screen in computer editing software. Connected to the
540
Glossary
computer by USB or FireWire, the controller surface might include analog
and digital input/output connectors and MIDI connectors.
CONVOLUTION REVERB (SAMPLING REVERB) A reverberation
device or plug-in which creates the reverb from impulse-response
samples (wave files) of real acoustic spaces, rather than from algorithms.
The resulting sound quality is very natural.
CROSSOVER An electronic network that divides an incoming signal
into two or more frequency bands.
CROSSOVER, ACTIVE (ELECTRONIC CROSSOVER) A crossover
with amplifying components, used ahead of the power amplifiers in a
bi-amped or tri-amped speaker system.
CROSSOVER FREQUENCY The single frequency at which both filters
of a crossover network are down 3 dB.
CROSSOVER, PASSIVE A crossover with passive (nonamplifying)
components, used after the power amplifier.
CROSSTALK The unwanted transfer of a signal from one channel to
another. Crosstalk often occurs between adjacent tracks within a record
or playback head in a tape recorder, or between input modules in a
console.
CUE, CUE SEND In a mixing-console input module, a control that
adjusts the level of the signal feeding the cue mixer that feeds a signal to
headphones in the studio.
CUE LIST See Edit Decision List.
CUE MIXER A submixer in a mixing console that takes signals from
cue sends as inputs and mixes them into a composite signal that drives
headphones in the studio.
CUE SHEET Used during mixdown, a chronological list of mixingconsole control adjustments required at various points in the recorded
song. These points may be indicated by counter or ABS-time readings.
CUE SYSTEM A monitor system that allows musicians to hear themselves and previously recorded tracks through headphones.
DAMPING FACTOR The ability of a power amplifier to control or
damp loudspeaker vibrations. The lower the amplifier’s output impedance, the higher the damping factor.
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Practical Recording Techniques
DAT (R-DAT) A digital audio tape recorder that uses a rotating head
to record digital audio on tape.
DATA COMPRESSION A data encoding scheme for reducing the
amount of data storage on a medium. Same as Data Reduction. See Compression, ATRAC, and MP3.
DAW
Abbreviation for digital audio workstation.
dB Abbreviation for decibel.
DEAD Having very little or no reverberation.
DECAY The portion of the envelope of a note in which the envelope
goes from maximum to some midrange level. Also, the decline in level
of reverberation over time.
DECAY TIME
See Reverberation Time.
DECIBEL The unit of measurement of audio level. Ten times the logarithm of the ratio of two power levels. Twenty times the logarithm of the
ratio of two voltages. dBV is decibels relative to 1 volt. dBu is decibels
relative to 0.775 volt. dBm is decibels relative to 1 milliwatt. dBA is decibels, A weighted. See Weighted.
DECODED TAPE A program on analog recording tape that is
expanded after being compressed by a noise-reduction system. Such a
program has normal dynamic range.
DE-ESSER A signal processor or plug-in that removes excessive sibilance (“s” and “sh” sounds) by compressing high frequencies around 5
to 10 kHz.
DELAY The time interval between a signal and its repetition. A digital
delay or a delay line is a signal processor that delays a signal for a short
time.
DELAY COMPENSATION Adjusting the timing of a track that is
processed by a plug-in, to make it in sync with non-processed tracks.
Plug-ins add latency (delay) to a track.
DEMAGNETIZER (DEGAUSSER) An electromagnet with a probe tip
that is touched to elements of an analog recorder tape path (such as tape
heads and tape guides) to remove residual magnetism.
DEPTH The audible sense of nearness and farness of various instruments. Instruments recorded with a high ratio of direct-to-reverberant
542
Glossary
sound are perceived as being close; instruments recorded with a low ratio
of direct-to-reverberant sound are perceived as being distant.
DESIGN CENTER The portion of fader travel (usually shaded), about
10 to 15 dB from the top, in which console gain is distributed for optimum
headroom and signal-to-noise ratio. During normal operation, each fader
in use should be placed at or near design center.
DESIGNATION STRIP A strip of paper taped near console faders to
designate the instrument that each fader controls. Also called a Scribble
Strip.
DESK The British term for mixing console.
DESTRUCTIVE EDITING In a digital audio workstation, editing that
rewrites the data on disk. A destructive edit cannot be undone unless a
copy of the original data is saved before the edit is done.
DI Short for direct injection, recording with a direct box.
DIFFUSION
An even distribution of sound in a room.
DIGITAL AUDIO An encoding of an analog audio signal in the form
of binary digits (ones and zeroes).
DIGITAL AUDIO WORKSTATION (DAW) A computer, audio interface, and recording software that allows you to record, edit, and mix
audio programs entirely in digital form. A standalone DAW is a digital
multitrack recorder-mixer. Standalone DAWs include real mixer controls;
computer DAWS have virtual controls on-screen.
DIGITAL RECORDING A recording system in which the audio signal
is stored as binary digits (ones and zeroes).
DIGITAL-TO-ANALOG (D/A) CONVERTER A circuit that converts a
digital audio signal into an analog audio signal.
DIM To reduce the monitor volume temporarily by a preset amount so
that you can carry on a conversation.
DIRECT BOX A device used for connecting an amplified instrument
directly to a mixer mic input. The direct box converts a high-impedance
unbalanced audio signal into a low-impedance balanced audio signal.
DIRECT INJECTION (DI) Recording with a direct box.
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Practical Recording Techniques
DIRECTIONAL MICROPHONE A microphone that has different
sensitivity in different directions. A unidirectional or bidirectional microphone.
DIRECT OUTPUT, DIRECT OUT An output connector following a
mic preamplifier, fader, and equalizer, used to feed the signal of one
instrument to one track of a multitrack recorder.
DIRECT SOUND Sound traveling directly from the sound source to
the microphone (or to the listener) without reflections. Also, DirectSound
is an audio driver for the Windows operating system, intended as an
enhancement to MultiMedia Extensions (MME).
DIRECTX (DX) A package of Windows audio, video, and gamecontroller drivers, also called multimedia application programming interfaces (APIs).
DISTORTION An unwanted change in the audio waveform, causing
a raspy or gritty sound quality. The appearance of frequencies in a
device’s output signal that were not in the input signal. Distortion is
caused by recording at too high a level, using improper mixer settings,
components failing, or vacuum tubes distorting. (Distortion can be desirable, e.g., for an electric guitar.) In digital recording, distortion called
quantization error can also occur at very low signal levels, where there
are not enough bits to record the signal accurately.
DITHER Low-level noise added to a digital signal to reduce quantization distortion caused by truncating (removing) bits in a digital word. It’s
a good idea to add dither to a 24-bit program just before converting it to
16 bits for CD release.
DOLBY DIGITAL A perceptual coding method using AC-3 data compression, offering 6 discrete channels of digital surround sound. Dolby
Digital uses a lossy encoding process to reduce the bit rate needed to
transmit the six channels via a 2-channel bitstream. The standard audio
format for DVD-Video.
DOLBY PRO LOGIC A surround decoder that decodes the two channels of Dolby-Surround-encoded programs back into four channels (left,
center, right, surround).
DOLBY SURROUND A matrix encoding system that combines four
channels (left, center, right, surround) into two channels. The Dolby Pro
Logic decoder unfolds the two channels back into four. The surround
544
Glossary
channel, which is mono and limited bandwidth, is reproduced over left
and right surround speakers.
DOLBY TONE A reference tone recorded at the beginning of a Dolbyencoded analog tape for alignment purposes.
DOUBLING A special effect in which a signal is combined with its 15to 35-msec-delayed replica. This process mimics the sound of two identical voices or instruments playing in unison. In another type of doubling,
two identical performances are recorded and played back to thicken the
sound.
DROP-FRAME For color video production, a mode of SMPTE time
code that causes the time code to match the clock on the wall. Once every
minute, frame numbers 00 and 01 are dropped, except every 10th minute.
DROP-OUT During playback of a tape recording, a momentary loss of
signal caused by separation of the tape from the playback head by dust,
tape-oxide irregularity, etc. During playback of a hard-disk recording, a
momentary loss of signal caused by a buffer memory being emptied.
Increasing buffer size usually prevents drop-outs.
DRUM MACHINE A device—hardware or software—that plays
samples of real drums and includes a sequencer to record rhythm
patterns.
DRY Having no echo or reverberation. Referring to a close-sounding
signal that has not yet been processed by a reverberation or delay device
or plug-in.
DSD (Direct Stream Digital) A process that encodes a digital signal in
a 1-bit (bitstream) format at a 2.8224 MHz sampling rate. Offers state-ofthe-art sound quality; used in the Super Audio CD.
DSP (Digital Signal Processing) Modifying a signal in digital form by
doing calculations on the numbers. DSP is used for level changes, EQ,
effects, and so on.
DTS (Digital Theater System) A perceptual coding method using data
compression, offering 6 discrete channels of digital surround sound. DTS
uses a lossy encoding process to reduce the bitrate needed to transmit the
6 channels via a 2-channel bitstream.
DVD (Digital Versatile Disc) A storage medium the size of a compact
disc that holds much more data. The DVD stores video, audio, or
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Practical Recording Techniques
computer data. DVD-RAM and DVD-R are recordable; DVD-RW is
rewritable, and DVD-A is audio only.
DVD-AUDIO A DVD intended mainly for audio programs. It can use
Dolby Digital or DTS encoded programs.
DX
See DirectX.
DXi DirectX Instruments, Cakewalk’s standard format for plug-in software synthesizers based on Microsoft DirectX technology.
DYNAMIC MICROPHONE A microphone that generates electricity
when sound waves cause a conductor to vibrate in a stationary magnetic
field. The two types of dynamic microphones are moving coil and ribbon.
A moving-coil microphone is usually called a dynamic microphone.
DYNAMIC RANGE The range of volume levels in a program from
softest to loudest.
EARTH GROUND A connection to moist dirt (the ground we walk on).
This connection is usually done via a long copper rod or an all-metal coldwater pipe.
EASI (Enhanced Audio Streaming Interface) Emagic’s sound card
driver spec. EASI achieves low latency by interfacing the sound card
directly with the audio application software.
ECHO A delayed repetition of a signal or sound. A sound delayed
50 msec or more that is combined with the original sound.
ECHO CHAMBER A hard-surfaced room containing a widely separated loudspeaker and microphone, once used for creating reverberation.
EDIT DECISION LIST (EDL) A list of program events in order, plus
their starting and ending times.
EDITING The cutting and rejoining of magnetic tape to delete
unwanted material, to insert silent spaces, or to rearrange recorded
material into the desired sequence. Also, the same actions performed
on a digital recording with a DAW, hard-disk recorder, or MiniDisc
recorder-mixer.
EDITING BLOCK A metal block that holds magnetic tape during the
editing/splicing procedure.
546
Glossary
EFFECTS Interesting sound phenomena created by signal processors,
such as reverberation, echo, flanging, doubling, compression, or chorus.
See Sound Effects.
EFFECTS BUS The bus that feeds effects devices (signal processors).
EFFECTS LOOP A set of connectors in a mixer for connecting an external effects unit, such as a reverb or delay device. The effects loop includes
a send section and a receive section. See Effects Send, Effects Return.
EFFECTS MIXER A submixer in a mixing console that combines
signals from effects sends, and then feeds the mixed signal to the input
of an effects device, such as a reverberation unit.
EFFECTS RETURN (AUX RETURN) In the output section of a mixing
console, a control that adjusts the amount of signal received from an
effects unit. Also, the connectors in a mixer to which you connect the
effects-unit output signal. They might be labeled “bus in” instead. The
effects-return signal is mixed with the program bus signal.
EFFECTS SEND (AUX SEND) In an input module of a mixing console,
a control that adjusts the amount of signal sent to an effects device, such
as a reverberation or delay unit. Also, the connector in a mixer that you
connect to the input of an effects unit. The effects-send or aux-send
control adjusts the amount of effects heard on each instrument.
EFFICIENCY In a loudspeaker, the ratio of acoustic power output to
electrical power input.
EIA Electrical Industries Association.
EIA RATING A microphone-sensitivity specification that states the
microphone output level in dBm into a matched load for a given sound
pressure level (SPL). SPL + dB (EIA rating) = dBm output into a matched
load.
ELECTRET-CONDENSER MICROPHONE A condenser microphone
in which the electrostatic field of the capacitor is generated by an
electret—a material that permanently stores an electrostatic charge.
ELECTROSTATIC FIELD The force field between two conductors
charged with static electricity.
ELECTROSTATIC INTERFERENCE The unwanted presence of an
electrostatic hum field in signal conductors.
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Practical Recording Techniques
ENCODED TAPE An analog tape containing a signal compressed by a
noise-reduction unit.
END-ADDRESSED Referring to a microphone whose main axis of
pickup is perpendicular to the front of the microphone. You aim the front
of the mic at the sound source. See Side-Addressed.
ENVELOPE The rise and fall in volume of one note. The envelope connects successive peaks of the waves that make up the note. Each harmonic
in the note might have a different envelope.
EQUALIZATION (EQ) The adjustment of frequency response to alter
the tonal balance or to attenuate unwanted frequencies.
EQUALIZER A circuit (usually in each input module of a mixing
console, or in a separate unit) that alters the frequency spectrum of a
signal passed through it.
ERASE To remove an audio signal from magnetic tape or disk by applying an ultrasonic varying magnetic field so as to randomize the magnetization of the magnetic particles on the tape or disk.
ERASE HEAD A head in a tape recorder or hard drive that erases the
signal on tape or disk.
EXPANDER 1. A signal processor that increases the dynamic range of
a signal passed through it. 2. An amplifier whose gain decreases as its
input level decreases. When used as a noise gate, an expander reduces
the gain of low-level signals to reduce noise between notes.
FADE-OUT To gradually reduce the volume of the last several seconds
of a recorded song, from full level down to silence, by slowly pulling
down the master fader, or by selecting a fade-out process in a digital
editing program.
FADER A linear or sliding potentiometer (volume control), used to
adjust signal level.
FEED 1. To send an audio signal to some device or system. 2. An output
signal sent to some device or system.
FEEDBACK 1. The return of some portion of an output signal to the
system’s input. 2. The squealing sound you hear when a PA system microphone picks up its own amplified signal through a loudspeaker.
548
Glossary
FEED REEL The left-side reel on an analog tape recorder that unwinds
during recording or playback.
FILTER 1. A circuit that sharply attenuates frequencies above or below
a certain frequency. Used to reduce noise and leakage above or below the
frequency range of an instrument or voice. 2. A MIDI filter removes
selected note parameters.
FIREWIRE A standard protocol for high-speed transfer of data between
digital devices. Also called IEEE 1394.
FLANGING A special effect in which a signal is combined with its
delayed replica, and the delay is varied between 0 and 20 msec. A hollow,
swishing, ethereal effect like a variable-length pipe, or like a jet plane
passing overhead. A variable comb filter produces the flanging effect.
FLETCHER–MUNSON EFFECT Named after the two people who
discovered it, the psychoacoustical phenomenon in which the subjective
frequency response of the ear changes with program level. Because of
this effect, a program played at a lower volume than the original level
subjectively loses low- and high-frequency response.
FLOAT
To disconnect from ground.
FLUTTER A rapid periodic variation in tape speed.
FLUTTER ECHOES A rapid series of echoes that occurs between two
parallel walls.
FLUX Magnetic lines of force.
FLUXIVITY The measure of the flux density of a magnetic recording
tape, per unit of track width.
FLY-IN (LAY-IN) To copy part of a recorded track onto another recorder,
then re-record that copy back onto the original multitrack tape in a different part of the song, in sync with other recorded tracks. For example,
copy the vocal track from the first chorus of the song onto an external
DAW or sampler. Re-record (fly-in) that copy onto the multitrack tape at
the second chorus. Then the first and second choruses have identical
vocal performances.
FOLDBACK (FB) See Cue System.
FREQUENCY The number of cycles per second of a sound wave or
an audio signal, measured in hertz (Hz). A low frequency (for example,
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Practical Recording Techniques
100 Hz) has a low pitch; a high frequency (for example, 10,000 Hz) has a
high pitch.
FREQUENCY RESPONSE 1. The range of frequencies that an audio
device will reproduce at an equal level (within a tolerance, such as ±3 dB).
2. The range of frequencies that a device (mic, human ear, etc.) can detect.
FULL-DUPLEX Describing a sound card that can record and play back
simultaneously. The card works on two DMA channels.
FULL TRACK A single tape track recorded across the full width of an
analog tape.
FUNDAMENTAL
The lowest frequency in a complex wave.
FX Abbreviation for Effects.
GAIN Amplification. The ratio, expressed in decibels, between the
output voltage and the input voltage, or between the output power and
the input power.
GAP In a tape-recorder head, the thin break in the electromagnet that
contacts the tape. In an audio program, the space or silence between
songs.
GATE 1. To turn off a signal when its amplitude falls below a preset
value. 2. The signal-processing device used for this purpose. See also
Noise Gate.
GATED REVERB Reverberation with the reverberant “tail” cut off
before it fades out.
GENERAL MIDI FILE (GM file) A MIDI file containing a standard set
of musical instrument sounds. A General MIDI file produces the same
sounds on any MIDI-capable instrument that supports the GM spec.
GENERATION A copy of a tape or a bounce of a track. A copy of the
original master recording is a first generation tape. A copy made from the
first generation tape is a second generation, and so on.
GENERATION LOSS The degradation of signal quality (the increase
in noise and distortion) that occurs with each successive generation of an
analog tape recording.
GOBO A moveable partition used to prevent the sound of an instrument from reaching another instrument’s microphone. Short for
go-between.
550
Glossary
GRAPHIC EQUALIZER An equalizer with a horizontal row of faders;
the fader-knob positions indicate graphically the frequency response of
the equalizer. Usually used to equalize monitor speakers for the room
they are in. Sometimes used for complex EQ of a track.
GROUND The zero-signal reference point for a system of audio
components.
GROUND BUS A common connection to which equipment is
grounded, usually a heavy copper plate.
GROUNDING Connecting pieces of electronic equipment to ground.
Proper grounding ensures that there is no voltage difference between
equipment chassis. An electrostatic shield needs to be grounded to be
effective.
GROUND LOOP 1. A loop or circuit formed of ground leads. 2. The
loop formed when unbalanced components are connected together via
two ground paths—the connecting-cable shield and the power ground.
Ground loops cause hum and should be avoided.
GROUP See Submix. 1. To select several faders to make them act in
unison. For example, select all the faders for the drum tracks to so that
you can adjust the overall level of the drums by pushing one fader. 2. To
assign the output of several input modules to a single group or bus,
whose level is controlled by a single group fader. For example, assign all
the input modules of the drum mics to a single “drums” group. 3. A bus
or channel in a mixer that contains the signals from several input
modules. For example, a drums group is a group of all the signals of the
drum-set mics.
GROUP FADER(submaster fader) In the output section of a mixing
console, a potentiometer (fader or volume control) that controls the
output level of a bus or group.
GSIF (GigaSampler Interface) Nemesys’ Windows sound card driver
that achieves low latency by interfacing directly between the sound card
and the audio application software.
GUARD BAND The spacing between tracks on a multitrack tape or
tape head, used to prevent crosstalk.
HALF-TRACK A tape track recorded across approximately half the
width of a tape. A half-track recorder usually records two such tracks
simultaneously in the same direction to make a stereo recording.
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Practical Recording Techniques
HARD DISK A random-access storage medium for computer data. A
hard-disk drive contains a stack of magnetically coated hard disks that
are read by, and written to by, an electromagnetic head.
HARD-DISK RECORDER (hard-drive recorder) A device dedicated to
recording digital audio on a hard-disk drive. A hard-disk recorder-mixer
includes a built-in mixer.
HARMONIC An overtone whose frequency is a whole-number multiple of the fundamental frequency.
HARMONIZER A signal processor that provides a wide variety of
pitch-shifting and delay effects.
HD Abbreviation for hard-disk drive.
HEAD An electromagnet in a tape recorder that either erases the audio
signal on tape, records a signal on tape, or plays back a signal that is
already on tape. A hard disk drive also has heads with similar functions.
HEAD GAP
See Gap.
HEADPHONES A head-worn transducer that covers the ears and converts electrical audio signals into sound waves.
HEADROOM The safety margin, measured in decibels, between the
signal level and the maximum undistorted signal level. In a tape recorder,
the dB difference between standard operating level (corresponding to a
0 VU reading) and the level causing 3% total harmonic distortion. Highfrequency headroom increases with analog tape speed.
HERTZ (Hz) Cycles per second, the unit of measurement of frequency.
HIGHPASS FILTER A filter that passes frequencies above a certain frequency and attenuates frequencies below that same frequency. A low-cut
filter.
HISS A noise signal containing all frequencies, but with greater energy
at higher octaves. Hiss sounds like wind blowing through trees. It is
usually caused by random signals generated by microphones, electronics, and magnetic tape.
HOST
A DAW recording program that supports plug-ins. See Plug-in.
HOT 1. A high recording level causing slight distortion, may be used
for special effect. 2. High average level on a CD making it relatively loud,
552
Glossary
produced by peak limiting and normalization, or by compression and
normalization. 3. A condition in which a chassis or circuit has a potentially dangerous voltage on it. 4. Referring to the conductor in a microphone cable that has a positive voltage on it at the instant that sound
pressure moves the diaphragm inward.
HUM An unwanted low-pitched tone (60 Hz and its harmonics) heard
in the monitors. The sound of interference generated in audio circuits and
cables by AC power wiring. Hum pickup is caused by such things as
placing audio cables near power cables or transformers, faulty grounding, poor shielding, and ground loops.
HYPERCARDIOID MICROPHONE A directional microphone with a
polar pattern that has 12 dB attenuation at the sides, 6 dB attenuation at
the rear, and two nulls of maximum rejection at 110 degrees off-axis.
IMAGE An illusory sound source located somewhere around the listener. An image is generated by two or more loudspeakers. In a typical
stereo system, images are located between the two stereo speakers.
IMPEDANCE The opposition of a circuit to the flow of alternating
current. Impedance is the complex sum of resistance and reactance.
Abbreviated as Z.
INPUT The connection going into an audio device. In a mixer or mixing
console, a connector for a microphone, line-level device, or other signal
source.
INPUT ATTENUATOR See Attenuator.
INPUT MODULE In a mixing console, the set of controls affecting a
single input signal. An input module usually includes an attenuator
(trim), fader, equalizer, aux sends, and channel-assign buttons.
INPUT/OUTPUT (I/O) CONSOLE (IN-LINE CONSOLE) A mixing
console arranged so that input and output sections are aligned vertically.
Each module (other than the monitor section) contains one input channel
and one output channel.
INPUT SECTION The row of input modules in a mixing console.
INSERT JACKS Two jacks (send and return) in a console input module
or output module that allow access to points in the signal path, usually
for connecting a compressor. Plugging into the access jacks breaks the
signal flow and allows you to insert a signal processor or recorder in
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Practical Recording Techniques
series with the signal. In many mixers, a single insert jack has both send
and return terminals. Also called Access Jacks.
I/O
Referring to Input and Output connectors.
I/O BOX A Breakout Box type of audio interface.
JACK A female or receptacle-type connector for audio signals into
which a plug is inserted.
KEYBOARD WORKSTATION Several MIDI components in one
chassis—a keyboard, a sample player, a sequencer, and perhaps a synthesizer and disk drive.
KILO
A prefix meaning one thousand. Abbreviated k.
LATENCY The signal delay through an A/D, D/A converter, through
a software program, or through a computer operating system. Monitoring latency is the delay between the time when a musician plays a note
and when she hears the monitored signal of that note. Latency can make
you play out-of-sync during overdubs.
LAY-IN
See Fly-In.
LEADERING
selections.
The process of splicing leader tape between program
LEADER TAPE Plastic or paper tape without an oxide coating, used for
a spacer between takes (for silence between songs) on analog tape.
LEAKAGE The overlap of an instrument’s sound into another instrument’s microphone. Also called bleed or spill.
LEDE Abbreviation for Live-End/Dead-End, a type of control room
acoustic treatment in which the front half of the control room prevents
early reflections to the mixing position, while the back half of the control
room reflects diffused sound to the mixing position.
LED INDICATOR
emitting diodes.
A recording-level indicator using one or more light-
LEVEL The degree of intensity of an audio signal—the voltage, power,
or sound pressure level. The original definition of level is the power in
watts.
LEVEL SETTING In a recording system, the process of adjusting the
input-signal level to obtain maximum level on the recording medium
554
Glossary
without distortion. A VU meter, LED meter, or other indicator shows
recording level.
LIGHTPIPE An Alesis connection protocol that transfers 8 digital audio
channels at once over a Toslink fiber-optic cable.
LIMITER A signal processor whose output is constant above a preset
input level. A compressor with a compression ratio of 10 : 1 or greater,
with the threshold set just below the point of distortion of the following
device. Used to prevent distortion of attack transients or peaks.
LINE LEVEL In balanced professional recording equipment, a signal
whose level is approximately 1.23 volts (+4 dBm). In unbalanced equipment (most home hi-fi or semipro recording equipment), a signal whose
level is approximately 0.316 volt (-10 dBV).
LIVE 1. Having audible reverberation. 2. Occurring in real time, in
person.
LIVE RECORDING A recording made at a concert. Also, a recording
made of a musical ensemble playing all at once, rather than overdubbing.
LOCALIZATION The ability of the human hearing system to tell the
direction of a real or illusory sound source.
LOCATE (Autolocate) A recorder function that makes the tape or disk
head go to a specified program address (counter time) at the press of a
button.
LOOP In a sampling program, to play the sustain portion of a sound’s
envelope repeatedly. Also, a repeated rhythmic or musical pattern.
LOUDSPEAKER A transducer that converts electrical energy (the
signal) into acoustical energy (sound waves).
LOWPASS FILTER A filter that passes frequencies below a certain frequency and attenuates frequencies above that same frequency. A high-cut
filter.
M
Abbreviation for mega, or one million (as in megabytes).
MAGNETIC RECORDING TAPE A recording medium made of magnetic particles (usually ferric oxide) suspended in a binder and coated on
a long strip of thin plastic (usually Mylar).
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Practical Recording Techniques
MAGNETO-OPTICAL DRIVE (MO DRIVE) A drive that stores
data (such as audio) on a 3.5-inch rewritable magneto-optical disk. The
drive uses a laser and magnetic head to write data, and a laser to read
data.
MASK To hide or cover up one sound with another sound. To make a
sound inaudible by playing another sound along with it. Masking is used
in many data reduction schemes.
MASTER A completed tape or CD used to generate tape copies or
compact discs.
MASTER FADER A volume control that affects the level of all program
busses simultaneously. It is the last stage of gain adjustment before the
2-track recorder.
MD
Abbreviation for MiniDisc.
Abbreviation for Modular Digital Multitrack.
MDM
MEMORY A group of integrated circuit chips used to store digital data
temporarily or permanently (such as an audio signal in digital format).
MEMORY RECORDER A device that records audio on a memory chip,
such as Compact Flash. Usually the recorded audio can be uncompressed
wave files or compressed MP3 files.
MEMORY REWIND A tape-recorder function that rewinds the tape to
a preset tape-counter position.
METER
level.
A device that indicates voltage, resistance, current, or signal
MFX The architecture or protocol for MIDI Effects. See MIDI Effects.
MIC
An abbreviation for microphone.
MIC LEVEL The level or voltage of a signal produced by a microphone,
typically 2 millivolts.
MIC PREAMP See Preamplifier.
MICROPHONE A transducer or device that converts an acoustical
signal (sound) into a corresponding electrical signal.
MICROPHONE TECHNIQUES The selection and placement of microphones to pick up sound sources.
556
Glossary
MIDI Abbreviation for Musical Instrument Digital Interface, a specification for a connection between synthesizers, drum machines, and
computers that allows them to communicate with and/or control each
other.
MIDI CHANNEL A route for transmitting and receiving MIDI signals.
Each channel controls a separate MIDI musical instrument or synth patch.
Up to 16 channels can be sent on a single MIDI cable.
MIDI CONTROLLER A musical performance device (keyboard, drum
pads, breath controller, etc.) that outputs a MIDI signal designating note
numbers, note on, note off, and so on.
MIDI/DIGITAL AUDIO SOFTWARE Software that combines a MIDI
sequencer with a multitrack digital audio recorder/editor.
MIDI EFFECTS (MFX) Non-audio processes applied to MIDI signals,
such as an arpeggiator, echo/delay, chord analyzer, quantize, transpose
MIDI event filter, or velocity change. They can be used as real-time, nondestructive plug-ins in MIDI tracks.
MIDI IN A connector in a MIDI device that receives MIDI messages.
MIDI INTERFACE A circuit that plugs into a computer and converts
MIDI data into computer data for storage in memory or on hard disk.
The interface also converts computer data into MIDI data.
MIDI OUT A connector in a MIDI device that transmits MIDI
messages.
MIDI THRU A connector in a MIDI device that duplicates the MIDI
information at the MIDI-IN connector. Used to connect another MIDI
device in the series.
MID-SIDE A coincident-pair stereo microphone technique using a
forward-facing unidirectional, omnidirectional, or bidirectional mic and
a side-facing bidirectional mic. The microphone signals are summed and
differenced to produce right- and left-channel signals.
MIKE To pick up with a microphone.
MILLI A prefix meaning one thousandth, abbreviated m.
MINIDISC (MD) A rewritable, magneto-optical storage medium that
is read by a laser. It resembles a compact disc in a 2.5-inch square housing.
MD recorders use a data compression scheme called ATRAC.
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Practical Recording Techniques
MIX 1. To combine two or more different signals into a common signal.
2. A control on an effects processor that varies the ratio between the dry
(unprocessed) signal and the processed signal.
MIXDOWN The process of playing recorded tracks through a mixing
console and mixing them to two stereo channels for recording on a
two-track recorder. Also applies to a surround-sound mixdown to 6 or 8
channels.
MIXER A device that mixes or combines audio signals and controls the
relative levels of the signals.
MIXING CONSOLE A large mixer with additional functions such as
equalization or tone control, pan pots, monitoring controls, solo functions, channel assigns, and control of signals sent to external signal
processors.
MLP (Meridian Lossless Packing) Used in DVD-Audio discs, a datareduction method that compresses six full-range channels of 24-bit, 96
kHz audio without data loss.
MMC (MIDI Machine Control) A set of MIDI commands by which one
device can control another. Some commands include Start, Stop, and
Locate. MMC does not include sync information, but MTC does.
MODELER A device or software that simulates the sound of a microphone, guitar amp, or room.
MO DRIVE See Magneto-Optical Drive.
MODULAR DIGITAL MULTITRACK (MDM) A multitrack tape
recorder that records 8 tracks digitally on a videocassette. Several 8-track
modules can be linked together to add more tracks in sync. Two examples of MDMs are the Alesis ADAT and TASCAM DA-88.
MONAURAL Referring to listening with one ear. Often incorrectly
used to mean monophonic.
MONITOR A loudspeaker in a control room, or headphones, used for
judging sound quality. Also, a video display screen used with a computer.
MONITORING
Listening to an audio signal with a monitor.
MONO, MONOPHONIC 1. Referring to a single channel of audio. A
monophonic program can be played over one or more loudspeakers, or
558
Glossary
one or more headphones. 2. Describing a synthesizer that plays only one
note at a time (not chords).
MONO-COMPATIBLE A characteristic of a stereo program, in which
the program channels can be combined to a mono program without
altering the frequency response or balance. A mono-compatible stereo
program has the same frequency response in stereo or mono because
there is no delay or phase shift between channels to cause phase
interference.
MOVING-COIL MICROPHONE A dynamic microphone in which the
conductor is a coil of wire moving in a fixed magnetic field. The coil is
attached to a diaphragm that vibrates when struck with sound waves.
Usually called a dynamic microphone.
MP3 (MPEG Level-1 Layer-3) A data compression format for audio. In
an MP3 file (.mp3), the data has been compressed or reduced to one-tenth
of its original size or less. Compressed files take up less memory, so they
download faster. You download MP3 files to your hard drive, then listen
to them. MP3 audio quality at a 128 kbps rate is nearly the same as that
of CDs (depending on source material).
MP3PRO A data-compression format for audio. MP3Pro is an improvement over MP3. Songs encoded at 64 kbps with MP3Pro are said to sound
as good as songs encoded at 128 kbps with MP3. MP3Pro offers faster
downloads and nearly double the amount of music you can put on a
flash-memory player. MP3 and MP3Pro files are compatible with each
other’s players, but an MP3Pro player is needed to hear MP3Pro’s
improvement in sound quality.
M-S RECORDING
See Mid-Side.
MTC (MIDI Time Code) A form of time code transmitted over MIDI,
used for synchronizing MIDI devices. Unlike SMPTE, MTC is not sampleaccurate.
MUDDY Unclear sounding; having excessive leakage, reverberation, or
overhang.
MULTIEFFECTS PROCESSOR See Multiprocessor.
MULTIPLE-D MICROPHONE A directional microphone that has multiple sound-path lengths between its front and rear sound entries. This
type of microphone has minimal proximity effect.
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Practical Recording Techniques
MULTIPROCESSOR A signal processor that can perform several different signal-processing functions.
MULTITIMBRAL In a synthesizer, the ability to produce two or more
different patches or timbres at the same time.
MULTITRACK Referring to a recorder with more than two tracks.
MUTE To turn off an input signal on a mixing console by disconnecting the input-module output from channel assign. During mixdown, the
mute function is used to reduce tape noise and leakage during silent
portions of tracks, or to turn off unused performances. During recording,
mute is used to turn off mic signals.
NEAR COINCIDENT A stereo microphone technique in which two
directional microphones are angled apart symmetrically on either side of
center and spaced a few inches apart horizontally.
NEARFIELD MONITORING A monitor-speaker arrangement in
which the speakers are placed very near the listener (usually just behind
the mixing console) to reduce the audibility of control-room acoustics.
NOISE Unwanted sound, such as hiss from electronics or tape. An
audio signal with an irregular, non-periodic waveform.
NOISE GATE
A gate used to reduce or eliminate noise between notes.
NOISE-REDUCTION SYSTEM A Dolby signal processor used to
reduce analog tape hiss (and sometimes print-through) caused by the
recording process. The object is to compress the high frequencies during
recording and expand them in a complementary way during playback.
NOISE SHAPING Filtering the noise added in dithering in order to
make the noise less audible. Usually the filter reduces the level in the
upper midrange and increases the level at high frequencies.
NONDESTRUCTIVE EDITING In a digital audio workstation,
editing done by changing pointers (location markers) to information on
the hard disk. A nondestructive edit can be undone.
NONLINEAR 1. Referring to a storage medium in which any data
point can be accessed or read almost instantly in a random fashion, rather
than sequentially. Examples are a hard disk, compact disc, and MiniDisc.
See Random Access. 2. Referring to an audio device that is distorting the
signal.
560
Glossary
NORMALIZE To raise the level of a digital audio signal so that the
highest peak in the program is at the highest level allowed by the recording. For example, in a normalized 16-bit recording, the highest peak in
the program has all 16 bits on: the highest possible level in a 16-bit
recording.
OCTAVE The interval between any two frequencies where the upper
frequency is twice the lower frequency.
OFF-AXIS Not exactly in front of a microphone or loudspeaker.
OFF-AXIS COLORATION In a microphone, the deviation from the onaxis frequency response that sometimes occurs at angles off the axis of
the microphone. The coloration of sound (alteration of tone quality) for
sounds arriving off-axis to the microphone.
OGG The file extension for Ogg Vorbis, a data-reduction encoding
scheme.
OMNIDIRECTIONAL MICROPHONE A microphone that is equally
sensitive to sounds arriving from all directions.
ON-LOCATION RECORDING A recording made outside the studio,
in a room or hall where the music usually is performed or practiced.
OPEN TRACKS On a multitrack tape recorder, tracks that have not yet
been used, or have already been bounced and are available for use.
ORTF Named after the French broadcasting network (Office de Radiodiffusion Television Française), a near-coincident stereo mic technique
that uses two cardioid mics angled 110 degrees apart and spaced 17 cm
horizontally.
OUTBOARD EQUIPMENT Signal processors that are external to the
mixing console.
OUTPUT A connector in an audio device from which the signal comes
and feeds successive devices.
OUTTAKE A take, or section of a take, that is to be removed or not
used.
OVERDUB To record a new musical part on an unused track in synchronization with previously recorded tracks.
OVERHANG The continuation of a signal at the output of a device
after the input signal has ceased. Sometimes called ringing.
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Practical Recording Techniques
OVERLOAD The distortion that occurs when an applied signal
exceeds a system’s maximum input level.
OVERSAMPLING Sampling an audio signal at a higher rate than is
needed to reproduce the highest frequency in the signal. For example,
sampling an audio signal at 8 times 44.1 kHz is called “8x oversampling.”
This process is followed by a digital low-pass filter and a gentle-slope
analog anti-alias filter. The result is less phase shift compared to a steep,
“brick-wall” analog filter used alone. See Anti-alias filter. Oversampling
also can be applied in D/A conversion.
OVERTONE In a complex wave, a frequency component that is higher
than the fundamental frequency.
PAD See Attenuator.
PAN POT Abbreviation for panoramic potentiometer. In each input
module in a mixing console, a control that divides a signal between two
channels in an adjustable ratio. By doing so, a pan pot controls the location of a sonic image between a stereo pair of loudspeakers.
PARAMETRIC EQUALIZER An equalizer with continuously variable
parameters, such as frequency, bandwidth, and amount of boost or cut.
PATCH 1. To connect one piece of audio equipment to another with a
cable. 2. A setting of synthesizer parameters to achieve a sound with a
certain timbre.
PATCH BAY (PATCH PANEL) An array of connectors, usually in a
rack, to which equipment inputs and outputs are wired. A patch bay
makes it easy to interconnect various pieces of equipment in a central,
accessible location.
PATCH CORD A short length of cable with a phone plug on each end,
used for signal routing in a patch bay.
PCM Abbreviation for Pulse Code Modulation, a method of analog-todigital conversion in which the instantaneous amplitude of an analog
waveform is measured or sampled several thousand times a second, and
each measurement is assigned a binary value of a certain number of bits
(ones and zeroes).
PDM Abbreviation for Pulse Density Modualtion, a method of of
analog-to-digital conversion in which the instantaneous amplitude of an
562
Glossary
analog waveform is coded as variations in the average number of fixedwidth pulses per unit of time.
PEAK On a graph of a sound wave or signal, the highest point in the
waveform. The point of greatest voltage or sound pressure in a cycle.
PEAK AMPLITUDE See Amplitude, Peak.
PEAKING EQUALIZER An equalizer that provides maximum cut or
boost at one frequency, so that the resulting frequency response of a boost
resembles a mountain peak.
PEAK PROGRAM METER (PPM) A meter that responds fast enough
to closely follow the peak levels in a program.
PERIOD The time between the peak of one wave and the peak of the
next. The time between corresponding points on successive waves.
Period is the inverse of frequency.
PERSONAL STUDIO A minimal group of recording equipment set up
for one’s personal use, usually using a 4-track cassette or memory
recorder-mixer. Also, a simple 4-track recorder-mixer for one’s personal
use.
PERSPECTIVE In the reproduction of a recording, the audible sense of
distance to the musical ensemble, the point of view. A close perspective
has a high ratio of direct sound to reverberant sound; a distant perspective has a low ratio of direct sound to reverberant sound.
PFL Abbreviation for pre-fader listen. See also Solo.
PHANTOM POWER A DC voltage (usually 12 to 48 volts) applied to
microphone signal conductors to power condenser microphones.
PHASE The degree of progression in the cycle of a wave, where one
complete cycle is 360 degrees.
PHASE CANCELLATION, PHASE INTERFERENCE The cancellation
of certain frequency components of a signal that occurs when the signal
is combined with its delayed replica. At certain frequencies, the direct and
delayed signals are of equal level and opposite polarity (180 degrees out
of phase), and when combined, they cancel out. The result is a comb-filter
frequency response having a periodic series of peaks and dips. Phase
interference can occur between the signals of two microphones picking
up the same source at different distances, or can occur at a microphone
picking up both a direct sound and its reflection from a nearby surface.
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Practical Recording Techniques
PHASING A special effect in which a signal is combined with its phaseshifted replica to produce a variable comb-filter effect. See also Flanging.
PHASE SHIFT The difference in degrees of phase angle between corresponding points on two waves. If one wave is delayed with respect to
another, there is a phase shift between them of 2piFT, where pi = 3.14,
F = frequency in Hz, and T = delay in seconds.
PHONE PLUG A cylindrical, coaxial plug (usually 1/4-inch diameter).
An unbalanced phone plug has a tip for the hot signal and a sleeve for
the shield, which connects to ground. A balanced phone plug has a tip
for the signal hot signal, a ring for the return signal, and a sleeve for the
shield.
PHONO PLUG A coaxial plug with a central pin for the hot signal and
a ring of pressure-fit tabs for the shield or ground. Also called RCA plug.
Phono plugs are used on Tascam modular digital multitrack recorders
and on consumer stereo equipment.
PINCH ROLLER In a tape-recorder transport, the rubber wheel that
pinches or traps the tape between itself and the capstan, so that the
capstan can move the tape.
PICKUP A piezoelectric transducer that converts mechanical vibrations
to an electrical signal. Used in acoustic guitars, acoustic basses, and
fiddles. Also, a magnetic transducer in an electric guitar that converts
string vibration to a corresponding electrical signal.
PING-PONGING See Bouncing Tracks.
PINK NOISE A noise signal containing all frequencies (unless bandlimited), with equal energy per octave. Pink noise is a test signal used for
equalizing a sound system to the desired frequency response, and for
testing loudspeakers.
PITCH The subjective lowness or highness of a tone. The pitch of a tone
usually correlates with the fundamental frequency.
PITCH CONTROL A control on a tape recorder that varies the tape
speed, thereby varying the pitch of the signal on tape. The pitch control
can be used to match the pitch of prerecorded instruments with that of
an instrument to be overdubbed. It is also used for special effects, such
as “chipmunk voices,” and to play prerecorded tracks slowly so that fast
musical passages can be overdubbed more easily.
564
Glossary
PITCH SHIFTER A signal processor that changes the pitch of an
instrument without changing its duration.
PLAYBACK EQUALIZATION In analog tape-recorder electronics,
fixed equalization applied to the signal during recording to compensate
for certain losses.
PLAYBACK HEAD The head in a tape recorder that picks up a prerecorded magnetic signal from the moving tape and converts it to a corresponding electrical signal. The playback head is not the same as the
sel-sync or sync head.
PLAYLIST
See Edit Decision List.
PLUG A male connector that inserts into a jack. Also, short for Plug-in.
PLUG-IN Effects software that you load into your DAW recording
program (called the host). The plug-in becomes part of the host program
and can be called up from within the host. Some manufacturers make
plug-in bundles, which are a variety of effects in a single package.
POLAR PATTERN The directional pickup pattern of a microphone. A
plot of microphone sensitivity plotted versus angle of sound incidence.
Examples of polar patterns are omnidirectional, bidirectional, and unidirectional. Subsets of unidirectional are cardioid, supercardioid, and
hypercardioid.
POLARITY Referring to the positive or negative direction of an electrical, acoustical, or magnetic force. Two identical signals in opposite
polarity are 180 degrees out-of-phase with each other at all frequencies.
POLYPHONIC Describing a synthesizer that can play more than one
note at a time (chords).
POP 1. A thump or little explosion sound heard in a vocalist’s microphone signal. Pop occurs when the user says words with “p,” “t,” or “b”
so that a turbulent puff of air is forced from the mouth and strikes the
microphone diaphragm. 2. A noise heard when a mic is plugged into a
monitored channel, or when a switch is flipped.
POP FILTER A screen placed on a microphone grille that attenuates
or filters out pop disturbances before they strike the microphone
diaphragm. Usually made of open-cell plastic foam or silk, a pop filter
reduces pop and wind noise.
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Practical Recording Techniques
PORTABLE STUDIO A combination recorder and mixer in one
portable chassis.
POST-ECHO A repetition of a sound, following the original sound,
caused by print-through.
POWER AMPLIFIER An electronic device that amplifies or increases
the power level fed into it to a level sufficient to drive a loudspeaker.
POWER GROUND (SAFETY GROUND) A connection to the power
company’s earth ground through the U-shaped hole in a power outlet. In
the power cable of an electronic component with a 3-prong plug, the Ushaped prong is wired to the component’s chassis. This wire conducts
electricity to power ground if the chassis becomes electrically hot, preventing shocks.
PREAMPLIFIER (PREAMP) In an audio system, the first stage of
amplification that boosts a mic-level signal to line level. A preamp is a
standalone device or a circuit in a mixer.
PRE-DELAY Short for pre-reverberation delay. The delay (about 30 to
150 msec) between the arrival of the direct sound and the onset of reverberation. Usually, the longer the pre-delay, the greater the perceived room
size.
PRE-ECHO A repetition of a sound that occurs before the sound itself,
caused by print-through in analog tape.
PRE-FADER/POST-FADER SWITCH A switch that selects a signal
either ahead of the fader (pre-fader) or following the fader (post-fader).
The level of a pre-fader signal is independent of the fader position; the
level of a post-fader signal follows the fader position.
PREPRODUCTION Planning in advance what you’re going to do at a
recording session, in terms of track assignments, overdubbing, studio
layout, and microphone selection.
PRESENCE The audible sense that a reproduced instrument is present
in the listening room. Some synonyms are closeness, definition, and
punch. Presence is often created by an equalization boost in the midrange
or upper midrange, and by a high direct-to-reverb ratio.
PRESSURE ZONE MICROPHONE A boundary microphone constructed with the microphone diaphragm parallel with, and facing, a
reflective surface.
566
Glossary
PREVERB A special effect in which the reverberation of a note precedes
it, rather than follows it. It turns a snare-drum hit into a whip sound, like
ssSSHHK! Chapter 10, Signal Processors and Effects, describes how to
create it. Also see Reverse Echo.
PRINT To record on tape or disc.
PRINT-THROUGH The transfer of a magnetic signal from one layer of
analog tape to the next on a reel, causing an echo preceding or following
the program.
PRODUCTION 1. A recording that is enhanced by effects. 2. The supervision of a recording session to create a satisfactory recording. This
involves getting musicians together for the session, making musical
suggestions to the musicians to enhance their performance, and making
suggestions to the engineer for sound balance and effects.
PROGRAM BUS A bus or output that feeds an audio program to a
recorder track.
PROGRAM MIXER In a mixing console, a mixer formed of inputmodule outputs, combining amplifiers, and program busses.
PRO TOOLS A popular digital audio editing platform for professional
use. It offers computer multitrack recording, overdubbing, mixing,
editing, and a variety of plug-in effects.
PROXIMITY EFFECT The bass boost that occurs with a single-D directional microphone when it is placed a few inches from a sound source.
The closer the microphone, the greater the low-frequency boost due to
proximity effect.
PULSE CODE MODULATION (PCM) A method of analog-to-digital
conversion. The analog signal voltage is measured several thousand
times a second, and each measurement is a digital word (a string of 1s
and 0s) of a certain word length or bit depth.
PULSE DENSITY MODULATION See PDM.
PUNCH-IN/OUT A feature in a multitrack recorder that lets you insert
a recording of a corrected musical part into a previously recorded track
by going into and out of record mode as the tape or disk is rolling.
PURE WAVEFORM A waveform of a single frequency; a sine wave. A
pure tone is the perceived sound of such a wave.
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Practical Recording Techniques
QUARTER-TRACK A tape track recorded across one-quarter of the
width of an analog magnetic tape. A quarter-track recorder usually
records two stereo programs (one in each direction).
RACK A 19-inch-wide wooden or metal cabinet used to hold audio
equipment.
RADIO-FREQUENCY INTERFERENCE (RFI) Radio-frequency electromagnetic waves induced in audio cables or equipment, causing
various noises in the audio signal.
RANDOM ACCESS Referring to a storage medium in which any data
point can be accessed or read almost instantly. Examples are a hard disk,
compact disc, and MiniDisc.
RAREFACTION The portion of a sound wave in which molecules are
spread apart, forming a region with lower-than-normal atmospheric pressure. The opposite of compression.
R-DAT
See DAT.
REALAUDIO A highly compressed audio file format used for streaming audio. Generally, RealAudio has lower fidelity (less treble) than MP3,
but the fidelity depends on modem speed. RealAudio files (.ra or.rm) are
often used as short excerpts or previews of songs.
REAL-TIME RECORDING 1. Recording notes into a sequencer in the
correct tempo, for later playback at the same tempo as recorded. 2. A
recording made direct to lacquer disc or direct to 2-track without any
overdubs or mixdown.
RE-AMPING Recording a guitar amp that is fed the signal from a
direct-recorded electric guitar track. This technique lets you work on the
amp’s sound during mixdown, rather than during recording.
RECIRCULATION (REGENERATION) Feeding the output of a delay
device back into its input to create multiple echoes. Also, the control on
a delay device that affects how much delayed signal is recycled to the
input.
RECORD To store an event in permanent form. Usually, to store an
audio signal in magnetic form on magnetic tape or disk, or to store an
audio signal in optical form on a CD-R or CD-RW. Recording is also possible on magneto-optical disk, on MiniDisc, in RAM, and on memory
cards.
568
Glossary
RECORD EQUALIZATION In analog tape-recorder electronics, equalization applied to the signal during recording to compensate for certain
losses.
RECORDER-MIXER A combination multitrack recorder and mixer in
one chassis.
RECORD HEAD The head in a tape recorder or hard drive that puts
the audio signal on tape or disk by magnetizing the tape or disk particles in a pattern corresponding to the audio signal.
RECORDING/REPRODUCTION CHAIN The series of events and
equipment that are involved in sound recording and playback.
REFLECTED SOUND Sound waves that reach the listener after being
reflected from one or more surfaces.
REGENERATION
See Recirculation.
REGION In a digital audio editing program, a defined segment of the
audio program. Also called clip or zone.
RELEASE The final portion of a note’s envelope in which the note falls
from its sustain level back to silence.
RELEASE TIME In a compressor, the time it takes for the gain to return
to normal after the end of a loud passage.
REMIX To mix again; to do another mixdown with different console
settings or different editing.
REMOTE RECORDING See On-Location Recording.
REMOVABLE HARD DRIVE A hard-disk drive that can be removed
and replaced with another, used in a DAWor hard-drive recorder to store
a program temporarily.
RENDER To convert one audio format to another in a DAW or harddrive recorder. Examples: mix a multitrack recording to a 2-channel wave,
aiff, rm, or mp3 file; convert a track with real-time effects to a track with
embedded effects; convert MIDI tracks to wave tracks; combine multiple
clips into a single track.
RESISTANCE The opposition of a circuit to a flow of direct current.
Resistance is measured in ohms, abbreviated w, and may be calculated
by dividing voltage by current.
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Practical Recording Techniques
RESISTOR An electronic component that opposes current flow.
RETURN-TO-ZERO See Memory Rewind.
REVERBERATION Natural reverberation in a room is a series of multiple sound reflections that make the original sound persist and gradually die away or decay. These reflections tell the ear that you’re listening
in a large or hard-surfaced room. For example, reverberation is the sound
you hear just after you shout in an empty gymnasium. A reverb effect
simulates the sound of a room—a club, auditorium, or concert hall-by
generating random multiple echoes that are too numerous and rapid for
the ear to resolve. The timing of the echoes is random, and the echoes
increase in number with time as they decay. An echo is a discrete repetition of a sound; reverberation is a continuous fade-out of sound.
REVERBERATION TIME (RT60) The time it takes for reverberation to
decay to 60 dB below the original steady-state level.
REVERSE ECHO A multiple echo that precedes the sound that caused
it, building up from silence into the original sound. This special effect is
created in a manner similar to preverb.
RFI See Radio Frequency Interference.
RHYTHM TRACKS The recorded tracks of the rhythm instruments
(guitar, bass, drums, and sometimes keyboards).
RIBBON MICROPHONE A dynamic microphone in which the conductor is a long metallic diaphragm (ribbon) suspended in a magnetic
field.
RIDE GAIN To turn down the volume of a microphone when the
source gets louder, and turn up the volume when the source gets quieter,
in an attempt to reduce dynamic range.
RINGING
See Overhang.
RMF (Rich Music Format) A format for a MIDI file with General MIDI
sounds plus custom sounds. Designed to be played on a Beatnik player.
ROOM MODES See Standing Wave.
RT60
SACD
570
See Reverberation Time.
See Super Audio CD.
Glossary
SAFETY COPY A copy of the master tape or CD, to be used if the
master is lost or damaged.
SAFETY GROUND See Power Ground.
SAMPLE 1. To digitally record a short sound event, such as a single
note or a musical phrase, into computer memory. 2. A recording of such
an event. 3. A measurement of an analog waveform that is done several
thousand times a second during a PCM A/D conversion.
SAMPLING 1. Recording a short sound event into computer memory.
The audio signal is converted into digital data representing the signal
waveform, and the data is stored in memory chips, tape, or disc for later
playback. 2. In PCM digital recording, measuring an analog waveform
periodically, several thousand times a second.
SAMPLING RATE In PCM digital recording, the frequency at which
an analog waveform is sampled or measured. The sampling rate of CDquality audio is 44,100 samples per second. The higher the sampling rate,
the higher the high-frequency response of the recording.
SATURATION Overload of magnetic tape. The point at which a further
increase in magnetizing force does not cause an increase in magnetization of the tape oxide particles. Distortion is the result.
SCENE AUTOMATION A form of console automation in which the
console settings are stored in memory. A “snapshot” or reading of many
of the settings is taken and stored for later recall. In contrast, dynamic
automation continuously follows the fader and knob moves, and the
automation data is usually stored as a MIDI file.
SCMS (Serial Copy Management System) An anti-copy scheme in
consumer digital audio devices (those with S/PDIF connectors). SCMS
circuits read flags in the data stream that allow users to make only firstgeneration copies, not copies of copies.
SCRATCH VOCAL A vocal performance that is done simultaneously
with the rhythm instruments so that the musicians can keep their place
in the song and get a feel for the song. Because it contains leakage, the
scratch-vocal recording is usually erased. Then the singer overdubs the
vocal part that is to be used in the final recording.
SCRUB To manually move an open-reel tape slowly back and forth
across a recorder playback head in order to locate an edit point. Some
digital editing software has an equivalent scrubbing function.
571
Practical Recording Techniques
SCSI (Small Computer Systems Interface) A standard spec for highspeed computer input and output. Commonly used for hard drives, CDROM drives, and CD-R recorders. Supports up to seven devices.
SENSITIVITY 1. The output of a microphone in volts for a given input
in sound pressure level. 2. The sound pressure level a loudspeaker produces at one meter when driven with 1 watt of pink noise. See also Sound
Pressure Level.
SEQUENCE A MIDI data file of musical-performance note parameters,
recorded by a sequencer.
SEQUENCER A device or computer program that records a musical
performance done on a MIDI controller (in the form of note numbers,
note on, note off, etc.) into computer memory or hard disk for later playback. During playback, the sequencer plays synthesizer sound generators
or samples.
SESSION 1. A time period set aside for recording musical instruments,
voices, or sound effects. 2. On a CD-R, a lead-in, program area, and
lead-out.
SHELVING EQUALIZER An equalizer that applies a constant boost or
cut above or below a certain frequency, so that the shape of the frequency
response resembles a shelf.
SHIELD A conductive enclosure (usually metallic) around one or more
signal conductors, used to keep out electrostatic fields that cause hum or
buzz. A shield in a mic cable is a cylindrical mesh of fine wires.
SHOCK MOUNT A suspension system that mechanically isolates a
microphone from its stand or boom, preventing the transfer of mechanical vibrations.
SIBILANCE In a speech recording, excessive frequency components in
the 5 to 10 kHz range, which are heard as an overemphasis of “s” and
“sh” sounds.
SIDE-ADDRESSED Referring to a microphone whose main axis of
pickup is perpendicular to the side of the microphone. You aim the side
of the mic at the sound source. See also End-Addressed.
SIGNAL A varying electrical voltage that represents information, such
as a sound.
572
Glossary
SIGNAL PATH The path a signal takes from input to output in a piece
of audio equipment.
SIGNAL PROCESSOR
trolled way.
A device that is used to alter a signal in a con-
SIGNAL-TO-NOISE RATIO (S/N) The ratio in decibels between signal
voltage and noise voltage. An audio component with a high S/N has little
background noise accompanying the signal; a component with a low S/N
is noisy.
SINE WAVE A wave following the equation y = sin x, where x is
degrees and y is voltage or sound pressure level. The waveform of a
single frequency. The waveform of a pure tone without harmonics.
SINGLE-ENDED 1. An unbalanced line. 2. A single-ended noise reduction system is one that works only during tape playback (unlike Dolby
or dbx, which work both during recording and playback).
SINGLE-D MICROPHONE A directional microphone having a single
distance between its front and rear sound entries. Such a microphone has
proximity effect.
SLAP, SLAP BACK An echo following the original sound by about 50
to 200 msec, sometimes with multiple repetitions.
SLATE At the beginning of a recording, a recorded announcement of
the name of the tune and its take number. The term is derived from the
slate used in the motion-picture industry to identify the production and
take number being filmed.
SMPTE TIME CODE A modulated 1200 Hz square-wave signal used
to synchronize two or more recorders or MIDI devices. SMPTE uses the
format HH : MM : SS : FF (hours, minutes, seconds, frames) to specify locations in the recorded program. SMPTE is an abbreviation for the Society
of Motion Picture and Television Engineers, who developed the time
code.
SNAKE A multipair or multichannel mic cable. Also, a multipair mic
cable attached to a connector junction box.
SNAPSHOT AUTOMATION
See Scene Automation.
SOFT SYNTH A synthesizer in software form.
573
Practical Recording Techniques
SOLO On an input module in a mixing console, a switch that lets you
monitor that particular input signal by itself. The switch routes only that
input signal to the monitor system.
SOUND Longitudinal vibrations in a medium (such as air) in the frequency range 20 to 20,000 Hz.
SOUND CARD A circuit card that plugs into a computer and converts
an audio signal into computer data for storage in memory or on hard
disk. The sound card also converts computer data into an audio signal.
A type of audio interface (see audio interface).
SOUND EFFECTS Recordings of non-musical sounds—such as a door
slam, gunfire, thunderstorm, car, or telephone—used in dramatic productions, radio spots and commercials. Not to be confused with Effects.
SOUND MODULE (SOUND GENERATOR) 1. A synthesizer without
a keyboard, containing several different timbres or voices. These sounds
are triggered or played by MIDI signals from a sequencer program, or by
a MIDI controller. A sound module can be a standalone device or a circuit
on a sound card. 2. An oscillator.
SOUND PRESSURE LEVEL (SPL) The acoustic pressure of a sound
wave, measured in decibels above the threshold of hearing. The higher
the SPL of a sound, the louder it is. dB SPL = 20 log(P/Pref), where P = the
measured acoustic pressure and Pref = 0.0002 dyne/cm2.
SOUND WAVE The periodic variations in air pressure radiating from
an object vibrating between 20 Hz and 20,000 Hz.
SPACED-PAIR A stereo microphone technique using two identical
microphones spaced several feet apart horizontally, usually aiming
straight ahead toward the sound source.
SPATIAL PROCESSOR A signal processor that allows images to be
placed beyond the limits of a stereo pair of speakers
even behind the
listener or toward the sides.
S/PDIF (Sony Philips Digital Interface; IEC 958 Type II) A 2-channel
digital signal interface format that uses a 75-ohm coaxial cable with RCA
connectors, or an optical cable with TOSLINK connectors. See also
AES/EBU.
SPEAKER
574
See Loudspeaker.
Glossary
SPECTRUM The output level versus frequency of a sound source,
including the fundamental frequency and overtones.
SPL See Sound Pressure Level.
SPLICE To join the ends of two lengths of magnetic tape or leader tape
with tape. Also, a splice is the taped joint between two lengths of magnetic tape or leader tape.
SPLICING BLOCK See Editing Block.
SPLIT CONSOLE A console with a separate monitor-mixer section. See
also Input/Output (I/O) Console.
SPLITTER A transformer or circuit used to divide a microphone signal
into two or more identical signals to feed different sound systems.
SPOT MICROPHONE In classical music recording, a close-placed
microphone that is mixed with more distant microphones to add presence or to improve the balance.
STANDING WAVE An apparently stationary waveform created by
multiple reflections between opposite room surfaces. At certain points
along the standing wave, the direct and reflected waves cancel, and at
other points the waves add together or reinforce each other.
STEM A submix in ProTools lingo-a drums submix, keys submix, leftfront submix, etc.
STEP-TIME RECORDING Recording notes into a sequencer one at a
time without regard to tempo, for later playback at a normal tempo.
STEREO, STEREOPHONIC An audio recording and reproduction
system with correlated information between two channels (usually discrete channels), meant to be heard over two or more loudspeakers to give
the illusion of sound-source localization and depth.
STEREO BAR, STEREO MICROPHONE ADAPTER A microphone
stand adapter that mounts two microphones on a single stand for convenient stereo miking.
STEREO IMAGING The ability of a stereo recording or reproduction
system to form clearly defined audio images at various locations between
a stereo pair of loudspeakers.
575
Practical Recording Techniques
STEREO MICROPHONE A microphone containing two mic capsules
in a single housing for convenient stereo recording. The capsules usually
are coincident.
STREAMING AUDIO Audio sent over the Internet in real time. A
streaming file plays as soon as you click on its title. A downloaded file
doesn’t play until you copy the entire file to your hard disk. Streaming
audio is heard almost instantly, but usually sounds muffled and can be
interrupted by Net congestion. With downloaded audio, you must wait
up to several minutes to hear the song, but the sound is high-fidelity and
continuous.
STUDIO
A room used or designed for sound recording.
SUBMASTER 1. A master volume control for an output bus. 2. A
recorded tape that is used to form a master tape.
SUBMIX A small preset mix within a larger mix, such as a drum mix,
keyboard mix, vocal mix, etc. Also a cue mix, monitor mix, or effects mix.
SUBMIXER A smaller mixer within a mixing console (or standalone)
that is used to set up a submix, a cue mix, an effects mix, or a monitor
mix.
SUPER AUDIO CD (SACD) An alternative to DVD-Audio, Super
Audio CD was developed by Sony and Philips. It is the size of a CD but
offers higher sound quality and 5.1 surround sound. SACD uses the
Direct Stream Digital (DSD) process, which encodes a digital signal in a
1-bit (bit-stream) format at a 2.8224 MHz sampling rate. This system offers
a frequency response from DC to 100 kHz with 120 dB dynamic range.
SUPERCARDIOID MICROPHONE A unidirectional microphone that
attenuates side-arriving sounds by 8.7 dB, attenuates rear-arriving sounds
by 11.4 dB, and has two nulls of maximum sound rejection at 125 degrees
off-axis.
SUPPLY REEL See Feed Reel.
SURROUND SOUND A multichannel recording and reproduction
system that plays sound all around the listener. The 5.1 surround system
uses the following speakers-front-left, center, front-right, left-surround,
right-surround, and subwoofer.
SUSTAIN The portion of the envelope of a note in which the level is
constant. Also, the ability of a note to continue without noticeably decaying, often aided by compression.
576
Glossary
SWEETENING The addition of strings, brass, chorus, etc., to a previously recorded tape of the basic rhythm tracks.
SYNC, SYNCHRONIZATION Aligning two separate audio programs
in time, and maintaining that alignment as the programs play.
SYNC, SYNCHRONOUS RECORDING Using a tape record head
temporarily as a playback head during an overdub session, to keep the
overdubbed parts in synchronization with the recorded tracks.
SYNC TONE See Tape Sync.
SYNC TRACK A track of a multitrack recorder that is reserved for
recording an FSK sync tone or SMPTE time code. This allows audio tracks
to synchronize with virtual tracks recorded with a sequencer. A sync track
also can synchronize two audio tape machines or an audio recorder and
a video recorder, and can be used for console automation.
SYNTHESIZER A musical instrument (usually with a piano-style keyboard) that creates sounds electronically and allows control of the sound
parameters to simulate a variety of conventional or unique instruments.
TAIL The end of a reverberation signal where the reverb fades down to
silence.
TAIL-OUT Referring to a reel of tape wound with the end of the
program toward the outside of the reel. Analog tape stored tail-out is less
likely to have audible print-through.
TAKE A recorded performance of a song. Usually, several takes are
done of the same song, and the best one
or the best parts of several—
becomes the final product.
TAKE SHEET A list of take numbers for each song, plus comments on
each take.
TAKE-UP REEL The right-side reel on a tape recorder that winds up
the tape as it is playing or recording.
TALKBACK An intercom in the mixing console for the engineer and
producer to talk to the musicians in the studio.
TAPE
See Magnetic Recording Tape.
TAPE LOOP An endless loop formed from a length of recording tape
spliced end-to-end, used for continuous repetition of several seconds of
recorded signal.
577
Practical Recording Techniques
TAPE RECORDER A device that converts an electrical audio signal
into a magnetic audio signal on magnetic tape, and vice versa. A tape
recorder includes electronics, heads, and a transport to move the tape.
TAPE SYNC A frequency-modulated signal recorded on a tape track,
used to synchronize a tape recorder to a sequencer. Tape sync also permits
the synchronized transfer of sequences to tape. See also Sync Track.
TDIF (TASCAM DIGITAL INTERFACE) An interface protocol for
connecting digital audio signals to and from TASCAM DTRS multitrack
recorders, such as the DA-78 and DA-88.
3-PIN CONNECTOR A 3-pin professional audio connector used for
balanced signals. Pin 1 is soldered to the cable shield, pin 2 is soldered
to the signal hot or in-polarity lead, and pin 3 is soldered to the signal
cold or opposite-polarity lead. See also XLR-Type Connector.
THREE-TO-ONE RULE (3 : 1 RULE) A rule in microphone applications. When multiple mics are mixed to the same channel, the distance
between mics should be at least three times the distance from each mic
to its sound source. This prevents audible phase interference.
THRESHOLD In a compressor or limiter, the input level above which
compression or limiting takes place. In an expander, the input level below
which expansion takes place.
TIE To connect electrically, for example, by soldering a wire between
two points in a circuit.
TIGHT 1. Having very little leakage or room reflections in the sound
pickup. 2. Referring to well-synchronized playing of musical instruments. 3. Having a well-damped, rapid decay.
TIMBRE The subjective impression of spectrum and envelope. The
quality of a sound that allows us to differentiate it from other sounds. For
example, if you hear a trumpet, a piano, and a drum, each has a different timbre or tone quality that identifies it as a particular instrument.
TIME CODE A modulated 1200-Hz square-wave signal used to synchronize two or more tape or disc transports. See also Tape Sync, Sync
Track, SMPTE Time Code.
TONAL BALANCE The balance or volume relationships among different regions of the frequency spectrum, such as bass, mid-bass,
midrange, upper midrange, and highs.
578
Glossary
TOSLINK (Toshiba Link)
data transfers.
A fiber-optic cable connection for S/PDIF
TRACK A path on magnetic tape containing a single channel of audio.
A group of bytes in a digital signal (on tape, on hard disk, on compact
disc, or in a data stream) that represents a single channel of audio
or MIDI. Usually one track contains a performance by one musical
instrument.
TRANSDUCER A device that converts energy from one form to
another, such as a microphone or loudspeaker.
TRANSFORMER An electronic component made of two magnetically
coupled coils of wire. The input signal is transferred magnetically to the
output, without a direct connection between input and output.
TRANSIENT A short signal with a rapid attack and decay, such as a
drum stroke, cymbal hit, or acoustic-guitar pluck.
TRANSIENT RESPONSE The ability of an audio component (usually
a microphone or loudspeaker) to follow a transient accurately.
TRANSPORT The mechanical system in a reproduction device that
moves the medium past the read/write heads. In a tape recorder, the
transport controls tape motion during recording, playback, fast forward,
and rewind.
TRIM 1. In a mixing console, a control for fine adjustment of level, as
in a Bus Trim control. 2. In a mixing console, a control that adjusts the
gain of a mic preamp to accommodate various signal levels.
TRS (Tip Ring Sleeve) A phone-plug connector used for aux
send/return, unbalanced stereo, or balanced mono connections.
TUBE A vacuum tube, an amplifying component made of electrodes in
an evacuated glass tube. Tube sound is characterized as being “warmer”
than solid-state or transistor sound.
TWEETER A high-frequency loudspeaker.
UNBALANCED LINE An audio cable having one conductor surrounded by a shield that carries the return signal. The shield is at ground
voltage.
UNIDIRECTIONAL MICROPHONE A microphone that is most sensitive to sounds arriving from one direction—in front of the microphone.
Examples are cardioid, supercardioid, and hypercardioid.
579
Practical Recording Techniques
UNITY GAIN A condition in which the input and output levels of a
device are equal.
USB (UNIVERSAL SERIAL BUS) A Mac/PC computer serial interface
for connecting external devices such as MIDI interfaces and audio interfaces to a computer. Faster than a standard serial port.
VALVE British term for vacuum tube. See Tube.
VBR(Variable Bit Rate MP3 encoding) The bit rate varies with the
audio signal.
VIRTUAL CONTROLS Audio-equipment controls that are simulated
on a computer monitor screen. You adjust them with a mouse or with a
controller surface.
VIRTUAL TRACK A recording of a single take of one instrument or
vocal on a random-access medium. The best parts of several virtual tracks
can be bounced a single track, forming a complete, perfect performance.
This process is called comping tracks.
VST (VIRTUAL STUDIO TECHNOLOGY) Steinberg’s virtual instrument integration standard format for plug-ins.
VU METER A voltmeter with a specified transient response, calibrated
in VU or volume units, used to show the relative volume of various audio
signals, and to set recording levels in analog tape recorders.
WAV (.WAV) A computer audio file format for Windows. It encodes
sound without any data reduction, using pulse code modulation. Its
audio resolution is 16-bit, 44.1 kHz, or higher.
WAVEFORM A graph of a signal’s sound pressure or voltage versus
time. The waveform of a pure tone is a sine wave.
WAVELENGTH The physical length between corresponding points of
successive waves. Low frequencies have long wavelengths; high frequencies have short wavelengths.
WEBER
A unit of magnetic flux.
WEIGHTED Referring to a measurement made through a filter with a
specified frequency response. An A-weighted measurement is taken
through a filter that simulates the frequency response of the human ear.
WINDOWS MEDIA See WMA.
580
Glossary
WINDSCREEN
See Pop Filter.
WMA (WINDOWS MEDIA AUDIO) A popular compressed audio file
format for streaming audio and for downloads. Windows Media 8
promises performance similar to that of MP3Pro-near-CD quality at 48
kbps and CD quality at 64 kbps.
WOOFER
A low-frequency loudspeaker.
WORD A binary number that is the value of each sample in an analogto-digital conversion. A sample is a measurement of an analog waveform
that is done several thousand times a second during a PCM A/D
conversion.
WORD LENGTH
See Bit Depth.
WORKSTATION A system of MIDI- or computer-related equipment
that works together to help you compose and record music. Usually, this
system is small enough to fit on a desktop or equipment stand. See also
Keyboard Workstation and Digital Audio Workstation.
WOW
A slow periodic variation in tape speed.
WRAPPER Software that converts a plug-in from an unsupported
format to a supported format. For example, a DAW recording program
(host) that cannot use VST plug-ins directly might include a wrapper that
converts VST plug-ins to Direct-X plug-ins.
XLR-TYPE CONNECTOR An ITT Cannon part number that has
become the popular definition for a 3-pin professional audio connector.
See alsoThree-Pin (3-Pin) Connector.
X-Y See Coincident-Pair.
Y-ADAPTER A cable that divides into two cables in parallel to feed one
signal to two destinations.
Z Abbreviation for impedance.
ZONE See Region.
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INDEX
A
AAC (MPEG Advanced Coding),
476
A–B (spaced pair) stereo miking,
124–126
Ableton Live, 394
Absolute Sound, The (magazine),
573
AC line voltage, 419
AC power distribution system,
418
Access time, 550
Accordions, 164
ACID products, 394
Acidized (RIFF) WAV file, 392
Acoustic bass, 155–56
Acoustic guitar, 149–51, 207
Acoustic treatments, 32
Acoustics, 26–29, 69, 325
control-room, 78–80
diffusion, 29
echoes, 26–27
leakage, 29
overview, 26
reverberation, 27–29
treating room for, 30–33, 69–70
AC-3, see Dolby digital
Active monitors, 77
A/D conversion, 316
A/D/A converter mode, 297
ADAT Lightpipe, 177, 294
Adobe Audition program, 303–6
AES/EBU digital, 176, 294
After-fader listen (AFL), 251
Airy, defined, 230
Alesis FirePort, 290, 291, 299
Alesis Lightpipe cable, 65
Alesis MasterLink, 362
Amazon.com, 522
Ambience microphone, 113
Ambience microphone arrays,
surround, 460
Amplification, 212
Amplifiers
analog summing, 299–300
guitar amplifier modelers,
228
miking, 132–33
power, 77–78
Amplitude, 21
Analog I/O, 294–95
Analog mixers, 239–53
additional features in large
mixing consoles, 251–53
input section, 240–47
aux, 245–47
channel assign switch, 244–45
direct out, 244
EQ, 244
input connectors, 241
input fader (channel fader),
244
input selector switch, 242–43
insert jacks, 243
mic preamp, 242
overview, 240–41
pan pot, 245
phantom power (P48, +48),
242
trim (gain), 242
monitor section, 250–51
output section, 247–50
bus output connectors, 248
group faders, 248
main output connectors,
248–49
master faders, 248–49
meters, 249–50
mixing circuits, 248
overview, 247–48
stereo mix bus, 248–49
overview, 239–40
Analog summing amplifiers,
299–300
Analog tape simulators, 227
Analog vs. digital, 171–72
Analog-to-digital (A/D) converter,
253
Anti-aliasing filter, 172–73
Anti-imaging filter, 173
Assigning
inputs to tracks, 259
patches to MIDI tracks, 373–74
Assistant engineer, 351–52
ATRAC (Adaptive Transform
Acoustic Coding), 187–88
Attack, 25
Attack time, 214
Audience microphones, 424–25
Audio files
compressed, uploading, 478–80
processed, 392
Web-related, 475–76
Audio Interchange File Format
(AIFF), 475
Audio Interchange File Format
(AIFF ) file, 174
Audio interfaces, 46, 289–99
Alesis FirePort, 299
for computer DAW, 11
control surface, 297–99
I/O breakout box, 292–97
analog I/O, 294–95
data transfer format, 293–94
digital I/O, 294
driver support, 295–96
interface options, 297
MIDI ports, 295
overview, 292–93
sampling rate and bit depth,
295
word clock, 295
overview, 289–90
sound card, 290–92
types of, 290
Audio magazines, 522–23
Audio restoration programs, 228
AudioSuite plug-ins, 311
Audition program, 303–6
583
Practical Recording Techniques
Automated mixing, 278–81
controls, 252
overview, 278
procedure, 280–81
snapshot vs. continuous
automation, 280
types of automation systems,
279–80
Automatic double tracking (ADT),
220
Automatic pitch correction, 227
Automation, continuous vs.
snapshot, 280
Automation systems, 279–80
Autopunch, 264, 375
Auto-Tune, 227
Aux, 245–47
Aux controls, 246–47
AUX knobs, 272
Aux output, FOH mixer, recording
off, 402–3
Aux-send function, 245
A-weighted self-noise spec, 98
B
Background vocals, 168–69
Backup, 198–99
Baffled omni pair, 127, 128–29
Bagpipes, 164
Balance
bad, 339–40
natural, 326
setting for, 270–71
tonal
bad, 340–41
good, 320–21
Balanced connections, 61, 294
Balanced line, 59–60
Balanced microphone pads, 400
Balanced vs. unbalanced
equipment levels, 495–96
Ballsy, defined, 230
Banjos, 156–57
Bandwidth, 204
Banks, 373
Bass
acoustic, 155–56
chorus, 221
compressor settings for, 216
electric, 135–36
management, 443–44
muddy, 340
584
part of audio spectrum, 202–03,
207
tight, 322–23
Bass chorus, 136
Bass guitar, see Electric bass
Bass traps, 33
Bassy, defined, 230
Battery powering, 297
Bi-amping, 77
Bidirectional mic, 91
Bidirectional pattern, 94
Big-band jazz, miking setup for,
162
Binaural head, five-channel
microphone with, 455–57
Biphase modulation, 561
Bit depth, 174, 295
Bitrate, 474
Blank recording media, 56, 398
Blanketed, defined, 235
Bleed, see Leakage
Bloated, defined, 230
Block diagrams, 412
Bloom, defined, 230
Bluegrass bands, 160
Blumlein array, 122
Books and videos, 521–22
Booms, 106
Boomy, defined, 230
Boost, 206–8
Bottom head, for drum tuning,
139
Bouncing tracks, 52
Boundary microphone, 94, 101–2,
113, 118, 145, 154
Bouzoukis, 157
Boxy, defined, 230
Brass, 161
Breaking down, 353
Breathing, in compression, 214
Breathy, defined, 230
Bright, defined, 230
Brittle, defined, 230
Bruck, Jerry, 454–55
Buffers, 315, 506
Burning reference CDs, 354–56
Bus in connectors, 245–46
Bus output connectors, 248
Buses, stereo mix, 248–49
Bus-mastering drivers, 551
BUS/MONITOR/CUE switch, 252
Bytes, 172–74
C
Cables, 59
connectors, 61–63
microphone, 106–7, 432
running, 421
and snakes, 415
speaker, 78
types, 63–65
Cakewalk Sonar program, 306–9
Calibration, 447–49
Cam-lok connectors, 418
Capacitor mic capsule, 88–89
CardBus cards, 294
Cardioid condenser microphone,
54
Cardioid dynamic microphone, 54,
105, 133, 140
Cardioid pattern, 91, 93
Cases, protective, 413–14
CD, see CD-R
CD checker, 362
CD-R, 183–87
burners, 47
burning, 183–86, 354, 360
data areas, 185
Disc-At-Once, 186–87
formats, 184–85
layers, 185
overview, 183–84
recording, see CD-R, burning
sessions, 186–87
standalone CD-R writer, 187
technology, 185–86
Track-At-Once, 186–87
transferring mastered program
to, 360–62
CD-RW, 183–84
CDRWIN program, 361
CDs, 462
burning, 354–56
encoding software and
hardware for, 469–70
for mastering, 356
programs for burning, 354
Super Audio, 466–67
surround encoding for, 467–68
Ceiling, reflections from, 167–68
Center speaker, 450
Center-channel buildup, 82
Central processing unit (CPU),
288, 552
Channel assign switch, 244–45
Index
Channel fader (input fader), 244
Channel strip, see Input module
Charbonneau, Guy, 420
Chase mode, 564
Chesty, defined, 231
Choir, 169–70
Chorus, 221
Church Production, 573
Clarinet, miking, 163–64
Clarity, 321, 332–33
Classical music recording
on-location, 429–38
editing, 438
equipment, 429–32
microphone placement, 435–37
overview, 429
preparing for session, 433–34
session setup, 434–35
stereo microphone techniques,
432–33
vs. popular recording, 317–18
Class