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AUDIO
FIRE
™
2
AUDIO
FIRE
™
4
AUDIO
FIRE
™
8
AUDIO
FIRE
™
12
Owner’s Manual Version 2.1 for Macintosh
Important Safety Instructions
1. Read Instructions - Be sure to read all of the safety and operating instructions before operating this product.
2. Retain Instructions - The safety instructions and owner's manual should be retained for future reference.
3. Heed Warnings - All warnings on your Echo product and in the Owner's
Manual should be followed.
4. Follow Instructions - All operating and use instructions should be followed.
5. Moisture - Water and moisture are detrimental to the continued good health of your Echo product. Do not install or operate your Echo product near sources of water or moisture such as sinks, damp basements, leaky roofs, etc.
6. Heat – Your Echo product should be situated away from sources of heat such as heaters or radiators.
7. Power Sources - This unit should be operated only from the type of power source indicated in this documentation or on your Echo product. If you are unsure about the type of power at your location, contact your local power company.
8. Grounding – Precautions should be taken so that the grounding capabilities of the unit are not undermined. The AudioFire 12 and AudioFire 8 are provided with a cord with an equipment grounding conductor and grounding plug. This plug must be plugged into an outlet that is properly installed and grounded in accordance with all local rules and ordinances. Do not modify the plug provided with the equipment. If the plug will not fit into your outlet, have a proper outlet installed by a qualified electrician.
9. Power Cord Protection – Power supply cords should be routed so that they are unlikely to be walked on or pinched by items placed upon or against them. Pay particular attention to protecting the plugs, outlets, and the point at which the cord exits your Echo product.
10. Servicing - Do not attempt to service this unit yourself, as opening the case will expose you to hazardous voltage or other dangers. All servicing should be referred to qualified service personnel.
11. Damage Requiring Service - Unplug this unit and refer it to a qualified service technician when any of the following occur: a) Objects have fallen or liquid has spilled into the unit b) The product has been exposed to rain or water c) The product does not operate normally or when a marked change in performance is noticed d) The product has been dropped or damaged in any way
Registering your product online at
http://www.echoaudio.com/support/register.php
allows us to register key information so that we may handle problems faster and inform you of advance information on upgrades and other news. Thank you in advance for registering. We hope you enjoy your Echo product.
Limited Warranty
Echo Digital Audio Corporation warrants this product, when purchased at an Authorized Echo Dealer in the United
States of America, to be free of defects in materials and manufacturing workmanship for a period of one year from the date of original purchase. During the warranty period Echo shall, at its option, either repair or replace any product that proves to be defective upon inspection by Echo. Final determination of warranty coverage lies solely with Echo. Echo reserves the right to update any unit returned for repair, and reserves the right to change or improve the design of the product at any time without notice.
This is your sole warranty. Echo does not authorize any third party, including any dealer or sales representative, to assume any liability on behalf of Echo or to make any warranty for Echo.
Service and repairs of Echo products are to be performed only at the factory (see below) unless otherwise authorized in advance by the Echo Service Department. Unauthorized service, repair or modification will void this warranty.
To obtain factory service:
Contact Echo Digital Audio Corporation at (805) 684-4593, 9AM to 4PM Monday through Friday (Pacific Time).
If necessary, you will be given a return authorization number. Products returned without an RA number will be refused. Echo may, at its option, require proof of the original date of purchase in the form of a dated copy of the original authorized dealer’s invoice or sales receipt. Pack the product in its original shipping carton and attach a description of the problem along with your name and a phone number where Echo can contact you if necessary.
Ship the product insured and freight prepaid to:
Echo Digital Audio Corporation
6450 Via Real
Carpinteria, CA 93013
DISCLAIMER AND LIMITATION OF WARRANTY
Echo makes no other warranties, express, implied, or otherwise, regarding Echo products, and specifically disclaims any warranty for merchantability or fitness for a particular purpose. The exclusion of implied warranties is not permitted in some states and the exclusions specified herein may not apply to you. This warranty provides you with specific legal rights. There may be other rights that you have which vary from state to state.
In no event will Echo be liable for any lost profits, or for any consequential, direct or indirect damages, however caused and on any theory of liability, arising from this warranty and sale.
©2009 by Echo Digital Audio Corporation
6450 Via Real
Carpinteria, CA 93013
Echo
®
and AudioFire
™ are trademarks of Echo Digital Audio Corporation.
Tracktion
™ is a trademark of LOUD Technologies Inc.
Apple
®
, FireWire
QuickTime
®
®
, iTunes
®
, iMovie
®
, iDVD
®
, Mac
®
, Macintosh
®
, Mac OS
, and GarageBand
™ are trademarks of Apple Computer, Inc.
®
, Power Mac
®
, PowerBook
®
,
INTRODUCTION....................................................................................................8
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Copy Version Information to Clipboard..........................................................35
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CONTACTING ECHO CUSTOMER SERVICE ..............................................42
APPENDIX A: GENERAL TROUBLESHOOTING GUIDE ..........................43
APPENDIX B: AN INTRODUCTION TO DIGITAL RECORDING .............47
Introduction
Introduction
Thank you for choosing Echo Digital Audio. We think you’ll find your Echo product to be an extremely flexible, high-performance tool for your computerbased hard disk recording system.
What You Should Have Received in the Box
When you opened the box, you should have found the following:
• An audio interface box
• Four mounting screws with collars (AudioFire 8 and AudioFire 12 only)
• Two removable rack-mount brackets (AudioFire 8 only)
• A FireWire cable
• A MIDI and S/PDIF dongle (AudioFire 2 only)
• A 4-pin to 6-pin FireWire adapter (AudioFire 2 and AudioFire 4 only)
• A power cable or power adapter
• A CD-ROM containing:
• Windows XP and Vista Drivers
• Mac OS X Drivers
• PDF Owner’s Manual
• Tracktion multitrack recording, MIDI, editing, and sampling software for Windows XP & Mac OS X (not included with the
AudioFire 8 w/ ADAT)
• HTML Tracktion User’s Guide (not included with the AudioFire 8 w/ ADAT)
.
• A Quick Start Guide
8
Introduction
Introduction
System Requirements
In order to use AudioFire 2, AudioFire 4, AudioFire 8, or AudioFire 12 you’ll need the following:
• An Apple brand Macintosh computer (desktop or notebook) with:
• Mac OS X (10.3.9 or later)
• An unused FireWire port
• A G4 or better processor (G5 recommended)
• A minimum 256Mb of RAM (512Mb highly recommended)
• A fast, high-capacity IDE, SCSI or FireWire hard disk drive
• Peripheral audio equipment, such as a mixer, microphones, studio monitors, musical instruments, etc.
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Introduction
Installation
Installation
To properly install your AudioFire product you will need to log in as an administrator, check your OS X version, run software update, connect the audio interface to a FireWire port and to your peripheral audio hardware and install the
Console software. The following steps will guide you through installing your
AudioFire product.
Log In as Administrator
In order to properly install your AudioFire product you need to make sure that you log in to your Mac with an account that has administrative privileges. To verify that your account has administrative privileges, open “System Preferences” from the Dock or from the Apple menu, select “Show All”, and then select “Accounts” in the “System” section. Now, select your account from the list on the left and click on the “Security” tab. Make sure that the checkbox at the bottom labeled “Allow user to administer this computer” is checked. If your account does not have administrative access, then you will need to log out and log in with an account that does.
Check OS X Version
OS X version 10.3.9 (or later) is required use your AudioFire product. If you have a version lower than 10.3.9, your AudioFire product may not install, or may not function properly. To check your OS X version open “About This Mac” from the
Apple menu. Verify that you have OS X version 10.3.9 or later. If you do not, then you will need to either purchase an upgrade or download it with Software Update.
Run Software Update
Before you install anything, you should make sure that you have the most recent updates for Mac OS X installed. This is especially important. If Mac OS X is out of date, you may not be able to use your AudioFire product at all. To do this, open
“Software Update” from the Apple menu. Download and install all of the updates, including updates for software like iTunes, iDVD, iMovie, QuickTime,
GarageBand, etc.
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Installation
Installation
Installing the AudioFire Hardware and Software
Now that you have logged in as an administrator, checked the OS X version, and updated your software, you are ready to install your AudioFire product in your computer.
1. Install the AudioFire Console. Insert the AudioFire Install CD-ROM into your machine. Simply drag the AudioFire Console to your Applications folder or whatever folder you prefer.
2. Once you have installed the console, locate the AudioFire interface box, the power cable, and the FireWire cable. If you are installing an AudioFire 8 or
AudioFire 12, securely mount the interface into your equipment rack. If you will not be mounting the box in a rack, then be sure to place the interface box in a secure location.
3. If you have AudioFire 8 or AudioFire 12, plug the power cable firmly into the interface and a power socket, and then turn on the interface by pressing the power button. If you have AudioFire 2 or AudioFire 4 your AudioFire can be powered directly through FireWire. No external power supply is needed. The
DC adapter is included for users of Windows notebook computers that have only an unpowered, 4-pin FireWire connector.
4. Plug one end of the FireWire cable into the FireWire connector on the rear of the AudioFire interface. Attach the other end of the FireWire cable to an open
FireWire port on your computer. (If the connector does not match the port on your computer then you will need to get an adapter.)
5. Your Mac will automatically recognize your new AudioFire product without any fanfare. See the “Software Configuration” section below for more info.
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Installation
Installation
NOTE: You should check the driver downloads area of our website
( www.echoaudio.com
) for any software updates and install them before continuing. The AudioFire hardware must be installed and powered on for the firmware update to load properly. You should also check the website periodically in the future in case any more updates are released at a later time.
6. You can now attach external audio devices to the connectors on the AudioFire interface box. Information on attaching external devices to the audio interface box may be found in the following section: “Connecting to the Audio
Interface”.
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Installation
Connecting to the Audio Interface
Connecting to the Audio Interface
The AudioFire 2, AudioFire 4, AudioFire 8 and AudioFire 12 audio interfaces contain a wide variety of connections that allow great flexibility in operation. For optimal performance, it is critical to use the appropriate cabling and connectors.
Analog Inputs and Outputs – AudioFire 2
AudioFire 2’s front panel has two analog line inputs (1 – 2), an amber power indicator light, and an 1/8” stereo headphone output jack, with a corresponding volume knob, which monitors analog outputs 3 and 4, labeled “Headphones” in the
AudioFire Console. The analog inputs operate with an input impedance of
10Kohms.
AudioFire 2 has two analog line outputs on the rear panel. The input and output connections can be used with balanced or unbalanced cables via the ¼” connectors.
By default, the inputs and outputs are set to receive or send a +4dBu signal.
You can switch between +4dBu and –10dBV for each individual input and output via the console software (see section below).
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Connecting to the Audio Interface
Connecting to the Audio Interface
Analog Inputs and Outputs – AudioFire 4
AudioFire 4’s front panel has two universal inputs (1 – 2) with meters and trim knobs, a phantom power indicator (+48v), and a power button with an amber power indicator light. There is also an 1/8” stereo headphone output jack, with a corresponding volume knob, which monitors analog outputs 1 and 2.
AudioFire 4 has two analog line inputs (3 – 4) and four analog line outputs on the rear panel. These analog inputs (3 – 4) operate with an input impedance of
10Kohms. The input and output connections can be used with balanced or unbalanced cables via the ¼” connectors. By default, the inputs and outputs are set to receive or send a +4dBu signal.
You can switch between +4dBu and –10dBV for each individual input and output via the console software (see section below).
Analog Inputs and Outputs – AudioFire 8
AudioFire 8’s front panel has two universal inputs (1 – 2) with meters and trim knobs, a phantom power switch and light (+48v), and a power button with an amber power indicator light (not shown below). There is also a ¼” stereo
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Connecting to the Audio Interface
Connecting to the Audio Interface
headphone output jack, with a corresponding volume knob, which monitors analog outputs 1 and 2.
AudioFire 8 has six analog line inputs (3 – 8) and eight analog line outputs on the rear panel. These analog inputs (3 – 8) operate with an input impedance of
10Kohms. The input and output connections can be used with balanced or unbalanced cables via the ¼” connectors. By default, the inputs and outputs are set to receive or send a +4dBu signal.
You can switch between +4dBu and –10dBV for each individual input and output via the console software (see section below). There are also two channel inserts on the rear panel where you can connect a serial effects device (compressor, EQ, etc.) for the universal inputs (1 – 2). The channel inserts are wired: tip = send, ring = return and sleeve = ground.
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Connecting to the Audio Interface
Connecting to the Audio Interface
The new AudioFire 8 (as of July 2009) now has optical S/PDIF and ADAT I/O, in addition to coaxial S/PDIF.
Universal Inputs – AudioFire 4 and AudioFire 8
The universal input connections can accept balanced or unbalanced signals via ¼” or XLR connectors. Since your AudioFire has built-in preamps, you can just plug your microphone or guitar cable right into the universal input. No external preamp, direct box, or mixer is needed!
To use a microphone, plug the microphone’s XLR cable into any of the universal inputs. Whenever an XLR cable is connected to a universal input, the microphone preamp is enabled and the gain range of the trim knob is set to range from +10 to
+59dB. The input impedance of each microphone preamp is 1.5Kohms. Full-scale input is 9dBu with the trim set to minimum gain.
Your AudioFire provides 48 volts of phantom power for microphones that require it. On AudioFire 4, to enable phantom power, press the button labeled +48v in the
AudioFire Console (the +48V LED will light up) and phantom power will be provided to all microphone inputs. On AudioFire 8, to enable phantom power, press the button labeled +48v on your audio interface box (the LED next to it will light up) and phantom power will be provided to all microphone inputs.
Note: Phantom power will not be applied to any line level equipment or guitars plugged in using cables with ¼” connectors.
To record a guitar or line level signal, just plug a cable with a ¼” connector into one of the universal inputs. Whenever a ¼” cable is connected to a universal input, the guitar/line preamp is enabled and the gain range of the trim knob is set to range
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Connecting to the Audio Interface
Connecting to the Audio Interface
from 0 to +45 dB. The guitar/line preamp can support both guitar & line level signals. The input impedance of each guitar/line preamp is 102Kohms. Full-scale input is 18dBu with the trim set to minimum gain.
If you want to adjust the input level of a universal input, just turn the trim knob and watch the corresponding level meter. The red light at the top will light anytime the input signal is greater than –6.5dBFS (or within 6.5dB of clipping). The yellow light represents a signal greater than –12.5dBFS, and the green light represents a signal greater than –36.5dBFS.
For optimal audio quality, you should adjust the input trim knob so that your loudest recorded signal lights up the yellow light, but not the red. When the red meter light shines extra bright – you’ve clipped! If the signal level ever exceeds
0dBFS the signal will be “clipped” and you will hear a “pop” or “tick” in the recording. This is a very bad thing, and clipping should be avoided at all costs!
There is enough headroom so that you can be conservative in this area, and there is no need to push the input levels right up to the edge of clipping.
Analog Inputs and Outputs – AudioFire 12
AudioFire 12’s front panel has meters for the twelve analog inputs and outputs, indicator lights for sample rate and clock synchronization, and a power button with an amber power indicator light (not shown below).
AudioFire 12 has twelve analog line inputs and twelve analog line outputs on the rear panel. The analog inputs operate with an input impedance of 10Kohms. The input and output connections can be used with balanced or unbalanced cables via the ¼” connectors.
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Connecting to the Audio Interface
Connecting to the Audio Interface
By default, the inputs and outputs are set to receive or send a +4dBu signal. You can switch between +4dBu and –10dBV for each individual input and output via the console software (see section below).
The FireWire Connector
On the rear panel of each AudioFire interface box is a pair of connectors with the
FireWire symbol above them. These six-pin IEEE 1394a connectors operate at 400
Mbps and are used to connect the audio interface to your computer, and to other
FireWire devices. These connectors do not pass power from the computer to other
FireWire devices, so other devices will require external power to function.
A FireWire cable was supplied with your AudioFire product.
S/PDIF (AudioFire 4 and AudioFire 8)
Next to the FireWire connectors on the back of AudioFire 4 and AudioFire 8 is a pair of connectors labeled S/PDIF, IN and OUT. These S/PDIF connectors are used to transmit digital audio data between digital audio devices via an electrical signal.
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Connecting to the Audio Interface
Connecting to the Audio Interface
When connecting devices to the S/PDIF jacks, the use of standard analog RCA audio cables is not recommended. For reliable S/PDIF operation, 75-ohm coaxial
(RG59) video cables are recommended.
Optical S/PDIF and ADAT (New 2009 AudioFire 8 only)
The new AudioFire 8 is now equipped with Optical S/PDIF and ADAT. There is a digital mode switch in the Echo console which lets you choose the digital format that you prefer.
MIDI
Your AudioFire is equipped with MIDI I/O connectors. The MIDI ports can be used for receiving MIDI time code (MTC), or sending and receiving MIDI signals between your digital audio/MIDI sequencing software and external sound modules, keyboards, MIDI controllers, etc.
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Connecting to the Audio Interface
Connecting to the Audio Interface
MIDI cabling is standardized and widely available.
MIDI and S/PDIF Dongle (AudioFire 2)
To conserve the space on your AudioFire 2, the MIDI and S/PDIF ports are located on an external cable included with your AudioFire 2. This cable connects to the
MiniDIN connector on the back of your AudioFire 2.
This cable can be left off when you are not using MIDI or S/PDIF. The S/PDIF and MIDI ports are labeled IN and OUT on the dongle.
The S/PDIF connectors are used to transmit digital audio data between digital audio devices via an electrical signal. When connecting devices to the S/PDIF jacks, the use of standard analog RCA audio cables is not recommended. For reliable S/PDIF operation, 75-ohm coaxial (RG59) video cables are recommended.
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Connecting to the Audio Interface
Connecting to the Audio Interface
The MIDI ports can be used for receiving MIDI time code (MTC), or sending and receiving MIDI signals between your digital audio/MIDI sequencing software and external sound modules, keyboards, MIDI controllers, etc. MIDI cabling is highly standardized and widely available.
Word Clock (AudioFire 8 and AudioFire 12 only)
Next to the MIDI ports are the Word Clock connectors. These connectors allow you to synchronize your Echo product to any other device equipped with a Word
Clock connector.
The Word Clock I/O uses a BNC connector. As with the S/PDIF I/O, a shielded
75-ohm (RG-59) coaxial video cable should be used. BNC connectors have been widely used in the electronics industry for both video and computer networking.
However, computer networks use 50-ohm (RG-58) coaxial cables and not the 75ohm (RG-59) cable used by video. For reliable word clock operation, use only video grade cables with your Echo product.
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Connecting to the Audio Interface
Software Configuration
Software Configuration
Now that you have installed your AudioFire product, you can verify that everything is working properly.
Open “System Preferences” from the Dock or Apple menu, select “Show All”, and select the “Sound” panel. Under the “Output” tab, you should see your AudioFire product listed as a sound output device. If you want to use your AudioFire product with iTunes, iDVD, iMovie, QuickTime, etc. you will need to select it as the sound output device.
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Software Configuration
Software Configuration
You can also check out your hardware with the “Audio MIDI Setup” application.
Go to your Applications folder on your hard disk and from there to the Utilities folder. Open “Audio MIDI Setup.”
In addition to listing all the audio devices in the system, Audio MIDI Setup lets you examine the various audio formats supported by the hardware in your Mac.
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Software Configuration
Software Configuration
By clicking on the “MIDI Devices” tab, you will display the available CoreMIDI devices. You should see your AudioFire product shown as an icon here.
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Software Configuration
Console Software
Console
If you followed the instructions in Step 1 of the “Installing the AudioFire
Hardware and Software” section of this manual, then you installed a “virtual control surface” application called the AudioFire Console. The console allows you to control the audio I/O and clocking functions of your AudioFire product, and it brings these controls to a single easy-to-use location. From the console you can control the output levels, select synchronization clocks and digital mode, and adjust input monitoring. The examples in this section will be for AudioFire 8. The controls for AudioFire 2, AudioFire 4 and AudioFire 12 are similar.
Running the Console
You can open the AudioFire console by going to the “Applications” folder (or wherever you chose to put it during installation) and double-clicking on the icon.
Alternatively, you can drag the icon to the Dock for easier access and just open it from there.
Automatic Flash Update
As the console starts up, it checks the firmware that is loaded in each AudioFire. If the AudioFire is running old firmware, a dialog will come up requesting your confirmation to update the firmware. If you click “Yes” the firmware will be updated to the latest version and you will need to restart your AudioFire before continuing.
Console Window
The basic metaphor for the console interface is a digital mixing board, and it works in terms of output busses. An output bus represents a pair of outputs on your
AudioFire hardware. For example, analog outputs 1 and 2 are an output bus. The console window allows you to select an output bus and control what is mixed and sent to that output bus. Audio played through the selected channels by an application, any analog input, and any digital input may be mixed to an output bus.
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Console Software
Console Software
The AudioFire 8 Console Window: Analog Out 1-2 Tab selected.
Bus Select Tabs
The output bus is selected by clicking on one of the tabs at the top of the console window. The above example shows the console window for AudioFire 8. Eight different output busses are shown here: four analog busses and four digital busses.
Note: The digital busses are collapsed in this view. To view the digital busses, click on the left facing arrow. This will collapse the analog busses and expand the digital busses. Metering activity is still visible on collapsed busses.
Each output bus has its own tab, marked either “Analog” or “Digital”, and a channel number pair. When you select a tab it will come to the front, and the other tab titles will be gray. In this case “Analog 1-2” is the currently selected output
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Console Software
Console Software
bus. Clicking on an output bus tab simply selects the settings that are displayed.
This means all input monitor parameters such as volume, pan, and mute only
apply to the audio coming out analog outputs 1 and 2 of AudioFire 8. To select, view and change the input monitoring and playback settings for another set of outputs you must select a different output bus by clicking on one of the other output bus tabs. AudioFire 12 does not have S/PDIF, so it does not have a digital output bus; it has 6 analog output bus tabs instead.
Master Output Bus Control
The master bus control is the area on the far right of the console window. At the top are the labels “ANALOG”, “Out 1”, and “Out 2.” This indicates you are currently controlling everything mixed to analog outputs 1 and 2. These channels correspond to the currently selected output bus tab.
Beneath the labels are two green label fields that can be changed by clicking in them and typing. Below the green label fields are nominal level buttons, mute buttons, level meters and faders. The mute buttons and faders affect everything
being mixed to this bus. Thus, pulling the fader down will make both the input monitors and playback quieter. The level meters display the amount of signal being sent out of the selected outputs.
The gang button sets the gang mode. If you are in gang mode, the mute buttons will work together for the left and right channels; for example, clicking the mute on one channel activates the mute button on the other channel. Also, ganging ties the faders together so they will maintain their relative placement in regard to each other.
Playback Controls
The playback controls are to the left of the master output controls and are similarly labeled, except instead of “Out” they are labeled “Play”. The playback controls affect the level of audio being played by an application out the currently selected output bus. These controls operate the same as the input monitor controls, except there are no pan knobs, solo buttons, or level meters.
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Console Software
Console Software
Analog Inputs
The controls for the analog inputs are on the left side of the console and have the labels “ANALOG” and “1” through “8” at the top. There is one strip, or input
channel, corresponding to each of AudioFire 8’s eight physical analog inputs. The input level meters remain visible at all times, whereas the input monitor controls
(pan, solo, mute, faders and gang) that you see will change depending on which output bus is currently selected.
The input monitor controls are a little complicated. Basically, there is a different
set of input monitor controls for each output bus, but only one set is visible and
changeable at a time. In the example above, the only set of input monitor controls that is visible and changeable is the one for the output bus called “Analog 1-2". To see and change a different set of input monitor controls you will need to select a different output bus (see the “Bus Select” section above).
The level meters do not change when a different output bus is selected. They always reflect the signal level being received on the inputs. For example, if you adjust the input faders to -12, this will decrease the amount the input signal that is being sent to analog outputs 1-2. Thus the signal level on the ANALOG Out 1-2 meters will be less than that on the input meters. If the Analog 3-4 tab is selected the console would appear as in the example below.
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Console Software
Console Software
The AudioFire 8 Console Window: Analog Out 3-4 Tab selected.
Note that since the Analog 3-4 tab is selected you are no longer looking at the input monitor and output controls for analog outputs 1 and 2. You are now looking at the controls for analog outputs 3 and 4. However, you can still see the input signal on the input level meters for Analog input 1-2.
At the top of each input channel, below the channel number, is a green label field that can be changed by clicking in it and typing. Below the label is the nominal level setting for that input channel. The labels, nominal levels, level meters and gang settings are the only things in this section that do not change when different output bus tabs are selected.
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Console Software
Console Software
Moving down the input channel strip you find the input monitor controls, starting with the input monitor pan knob. This knob changes how the input channel is monitored between the two channels of the currently selected output bus. Holding the Ctrl key and clicking on a pan knob will set it to the center position. Below each pan knob is a non-selectable green field that tells you the current setting of the pan knob. Note that adjusting the pan knob will not affect your recording, as the input monitor controls only affect how the input signal is sent to (or monitored on) the outputs.
Below the pan knob are the monitor solo and mute buttons. Activating the solo button will make sure that the selected output bus only monitors the inputs that are soloed. Activating the mute button on an input channel will prevent it from being monitored by the currently selected output bus. Again, this does not affect recording. These are followed by the monitor fader, which controls the input monitor level. Like the pan, solo, and mute controls, this does not affect your recording level. The faders also have gang buttons, and their operation is the same as the gang button for the master output bus controls.
Digital Inputs (AudioFire 2, AudioFire 4 and AudioFire 8)
The controls for the digital inputs can found to the right of the analog input controls and have the labels “Digital” 1-8 at the top. Their operation is identical to the analog inputs.
Note: Even though 8 Digital Input channels are always visible, they are not always available depending in which Digital Mode you are using. S/PDIF coax and
S/PDIF optical only use inputs 1-2. ADAT optical at 44.1K or 48K uses inputs 1-8 and ADAT optical at 88.2 or 96K uses inputs 1-4.
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Console Software
Console Software
The AudioFire 8 Console Window: Digital Out 1-2 Tab selected.
Adjusting Playback Volume
Output volume adjustments are made in the digital domain. When you lower a volume fader below 0dB, you are actually decreasing the number of available bits, thereby taking away from the potential dynamic range of the system. Therefore, we suggest that whenever possible you leave the output faders (Playback & Output
Bus) set to 0dB, and perform any necessary attenuation on your external mixer.
When the playback volume controls are set to 0dB and the input signal approaches the maximum pre-clipping level, you can achieve the full 24-bit dynamic range of the system.
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Console Software
Console Software
Nominal Levels
The console buttons that are labeled “+4” or “-10” are nominal level buttons.
These buttons allow you to change the nominal level settings for the analog inputs and outputs. By default, the levels are set to send a +4dBu signal. You can switch between +4dBu (professional level) and –10dBV (consumer level) for each analog output and input by clicking on the appropriate button. This feature allows you to connect either professional or consumer gear to each input and output.
Settings Tab
Clicking the “Settings” tab allows you to access settings for controlling your
AudioFire hardware. The Settings page includes the Sample rate, Core Audio sample rate (Vista only), Clock source, Digital mode, S/PDIF format, Wave devices, Buffer size and the About button.
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Console Software
Console Software
The AudioFire 8 Console Window: Analog Out 3-4 Tab selected.
Sample Rate
The sample rate for your AudioFire hardware is set here. The sample rate, also known as clock rate, affects recording and playback. For more information please refer to Appendix C: An Introduction to Digital Recording. The application or audio software you are using may change the sample rate. The settings tab gives you an easy way to see exactly what sample rate your audio is set to.
You can also set the sample rate in Audio-MIDI Setup.
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Console Software
Console Software
Clock Source
Under clock source you may select the input clock source. The clock source setting is used to synchronize your AudioFire hardware to another piece of audio hardware. If a given synchronization source (input clock) is not detected, that clock source will be grayed out. You will only be allowed to select input clocks that are currently connected. For more information please refer to “Synchronizing
Multiple Devices” later in this manual.
If an external clock is selected and that clock is disconnected, the button will turn red. You will either need to reconnect the clock source or select the internal clock button.
Digital Mode (AudioFire 8 only)
There are three different digital modes: S/PDIF coax, S/PDIF optical and ADAT optical. Click on the mode that best suits your needs. For instance, if you want to sync to ADAT, you will need to click on the ADAT optical button.
Note: At 44.1K and 48K there are 8 channels of ADAT available. At 88.2K and
96K there are only 4 channels of ADAT available.
About Dialogue Box
Version Information
Version information for all the components of your AudioFire system is displayed in the About Dialogue Box which can be found on the Settings Tab. Simply click on the About button. Note that when the About Dialogue Box is open, you are frozen out of the console until you close this box.
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Console Software
Console Software
Copy Version Information to Clipboard
The About Dialogue Box also has a button labeled "Copy to clipboard". Clicking this button will copy all of the version information displayed on this dialog to the system clipboard; you can then paste it into an e-mail if you need to communicate with our customer service.
The AudioFire 8 About Dialogue box
Flash Update
The console will automatically update your firmware. If you want to re-flash your hardware to this release of the firmware, click on "Flash update".
When you click this button, the console will load the current version of the firmware into the box. Note that this will also erase any settings you have saved to the flash memory.
AudioFire2 and AudioFire4 Playback Routing
The AudioFire2 and AudioFire4 now support routing playback from the computer to different physical outputs.
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Console Software
Console Software
Audio applications see the AudioFire’s outputs listed as "Playback 1" through
"Playback 6". Using the console, you can then route the playback channels to either the analog outputs, headphones (AudioFire2 only), or digital outputs. Each playback pair can be independently routed to any of the outputs. You can also duplicate playback pairs so the same audio goes to more than one set of outputs.
To change the routing, open the AudioFire Console. Select the Settings tab; near the bottom of the window you will see the new routing control.
The AudioFire 2 Console Window: Settings Tab selected
36
Console Software
Console Software
Console Sessions
The AudioFire console supports saving and loading the state of the AudioFire device to a file, called a “session”.
Sessions are stored in the “(My) Documents” folder in a sub-folder named after the device. For example, AudioFire 8 sessions are stored in a folder named
“AudioFire 8 sessions”.
To save or load a session, select one of the audio output tabs at the top of the console window and click the appropriate button.
To restore the device to its default state, click the “Reset” button.
The “Gang” buttons, the “Phantom power” button, “Clock source” buttons, the
“Sample rate” buttons, the “Locked” sample rate button, and “Buffer size” do not reset.
The “Locked” sample rate button, and “Buffer size” do not save.
Console Settings and Stand-Alone Mode
When the console is closed, all the console mixer settings for your AudioFire are saved to flash memory in the AudioFire. So, these settings will be recalled when you reboot your AudioFire or move it to another computer.
Your AudioFire need not be connected to a computer to operate. This is called
stand-alone mode. Simply set the mixer setting as you desire in the console and close the console to save those settings to flash memory. Then, when you turn on your AudioFire, those settings will automatically be loaded into the AudioFire’s internal mixer.
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Console Software
Console Software
Synchronizing External Devices
Your AudioFire is designed to work alongside other audio equipment. If you are planning on using your AudioFire with other audio equipment, please note the following:
You can use your AudioFire product with other audio devices outside of your computer, but in order for accurate synchronization to occur, the other audio product(s) must support a synchronization mode that is compatible with your
AudioFire hardware. Without such synchronization, the individual pieces of equipment will act independently of each other. This scenario may be fine for some musical applications; however, it is not appropriate for situations where sampleaccurate synchronization is required.
Let’s take a brief look at the various synchronization types.
Word Clock – The Word Clock connectors can be found on the back panel of
AudioFire 8 or AudioFire 12. When your AudioFire product is set to “Internal” this synchronization clock runs at the AudioFire product’s selected sample rate.
Think of it as a kind of electronic metronome, which clicks back and forth at the digital sample rate. It is one of the most widely used forms of synchronization in digital audio. Your AudioFire product is always generating Word Clock on its
Word Clock output BNC connector. Although it can generate Word Clock at any sample rate it is set to, your AudioFire product can only sync to Word Clock if the master device is set to a sample rate between 30kHz and 100kHz (200kHz for
AudioFire 12). Otherwise you will get noise and/or loss of sync.
ADAT – The Alesis ADAT optical interface can send and receive up to 8 simultaneous channels of digital audio data over fiber optic cables. Unlike wire cables, fiber optic cables do not add noise or interference. The new AudioFire 8 can send out (or “master”) ADAT clock as well as slave to it. If you want your
AudioFire 8 to slave to an ADAT clock, just set the input clock to the ADAT setting. Your AudioFire 8 can only sync to ADAT clock if the master device is set to a sample rate between 30kHz and 100kHz. Otherwise you will get noise and/or loss of sync.
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Console Software
Console Software
Note: To preserve the high audio quality of the AudioFire 8’s converters it is best to use the internal input clock setting instead of synchronizing to an external
ADAT clock, which may add unwanted jitter to the signal.
S/PDIF (AudioFire 2, AudioFire 4 and AudioFire 8) – The Sony/Phillips Digital
Interchange Format is a serial bit-stream that has a clock signal embedded in the data stream. When recording from an S/PDIF source, your AudioFire will utilize the synchronization clock that is embedded in the S/PDIF while it decodes the bitstream. Your AudioFire can only sync to S/PDIF clock if the master device is set to a sample rate between 30kHz and 100kHz. Otherwise you will get noise and/or loss of sync.
Note: When synchronizing your AudioFire product to an external device via
S/PDIF or Word Clock, you must set the AudioFire to the correct base clock rate.
See the following table for the correct base clock rate setting.
AudioFire 12 Only
External Clock Rate 30kHz – 50kHz 50kHz-100kHz 100kHz-200kHz
AudioFire Base
Clock Rate
44.1kHz or
48kHz
88.2kHz or
96kHz
176.4kHz or
192kHz
Now let’s take a look at some sample configurations and how you might set them up from a synchronization standpoint.
Let’s start with a simple example. Suppose that AudioFire 8 is the only audio device used in your studio. Since you have no other devices to synchronize with, simply select Internal for AudioFire 8’s input clock. AudioFire 8 will then use its own clock to control its operation.
Now a little more complicated set-up: You want to have an AudioFire 8 synchronized to another device via word clock. Simply set the AudioFire 8 to
Internal for its input clock. Now connect the AudioFire 8 to the other device via a
BNC cable running from Word Clock Out on the AudioFire 8 to Word Clock In on other device. Now select Word for the other device’s input sync. The other device will slave to your AudioFire 8 and they will now operate in unison.
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Console Software
Console Software
No matter how many devices you are synchronizing, the concept is essentially the same. You are merely “daisy-chaining” devices together using compatible clocks.
One device will operate as the source of the master clock, with each successive device using that clock to sync.
Connecting to your computer
You can connect multiple AudioFires to your computer by daisy chaining FireWire cables (connecting one AudioFire to the next) or by connecting each AudioFire to a different FireWire connector on your computer. AudioFire 12s, AudioFire 8s,
AudioFire 4s and AudioFire 2s can be mixed in any order and the clock master can be anywhere in the chain. Note that 192kHz will only be supported when only
AudioFire 12s are used.
Clocking
When using multiple AudioFires, they MUST BE clock synced together as explained in the previous section “Synchronizing Multiple Devices.” Using a BNC word clock cable, a S/PDIF cable or ADAT optical cable connect from the out to the in of the next AudioFire. In this manner, each AudioFire must be daisy chained. The first AudioFire in the chain is the clock master, the rest are clock slaves. On the “Settings” tab of the AudioFire Console you must set each
AudioFire to the correct clock settings. The clock master should be set to
“Internal” clock and the slaves should be set to “Word” clock, “S/PDIF” or
“ADAT”. If these settings are changed while audio is running, sync will be lost and your AudioFires will stop working until they are re-synced and the audio is restarted.
Console and Channel Names
When you install your AudioFire, a 4-digit number will be appended giving it a unique name. So if you install multiple AudioFires, each will have a unique number. In the installation examples above, the AudioFire is designated
“AudioFire 8 (0312).” In the Console examples, the AudioFire is designated
“AudioFire 8 (0409).” (This is because two different audio interfaces were used.)
This name will appear in your “Sound” panel and your “Audio MIDI Setup” panel.
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Console Software
Console Software
With multiple AudioFires, multiple console windows will open when you open the console. Each console will be identified by the AudioFire’s unique name.
41
Console Software
Appendix A: Troubleshooting Guide
Contacting Echo Customer Service
If you experience any trouble with your Echo hardware please go to the support area of our website at www.echoaudio.com
, and check out the “QuickTips” &
FAQ’s we have there. If you can’t find a solution to your problem there, please contact technical support via email. There is an example form that can be copied and sent to our technical support staff, and they will respond to you quickly.
Please fill in all the details completely. The best way to get the help you need is by giving us plenty of detailed information about your computer system, your audio software and hardware, and the problem you are having.
We do ask you to please read through this manual and the support area of our website before contacting us. Also, you may find an answer to your problem in the
Appendices of this document – starting on the next page.
Thank you for buying an Echo product!
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Appendix A: Troubleshooting Guide
Appendix A: Troubleshooting Guide
Appendix A: General Troubleshooting Guide
Problem: You can’t get your AudioFire product to install properly under Mac OS
8, OS 9, or OS X (10.3.8 or lower).
Solution: There is no driver support for AudioFire 8 or AudioFire 12 under Mac
OS 8 or 9. There is only driver support for Mac OS X (10.3.9 or later).
Problem: You’ve installed your AudioFire product, but it isn’t listed in the System
Preferences or the Audio MIDI Setup application.
Solution: Your installation of OS X may be out of date. Try running Software
Update; you’ll find it in the System Preferences. You need version 10.3.9 or later.
Problem: You can’t use more than one Echo product at a time with your audio software.
Solution: This is a limitation of your audio software. Currently, Apple’s
CoreAudio spec does allow multiple hardware devices to be used simultaneously by an audio software program, but most audio software programs currently do not support this feature.
Problem: When you connect a bus powered FireWire device to your AudioFire product it does not receive power.
Solution: Your AudioFire product does not pass power from the computer on its
FireWire connector. Use a FireWire device with an external power adapter.
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Appendix A: Troubleshooting Guide
Appendix A: Troubleshooting Guide
Problem: You are unable to get your DAT recorder to recognize the S/PDIF output from AudioFire 2, AudioFire 4 or AudioFire 8.
Solution: Digital information is transmitted in either of two modes, “professional” or “consumer.” The professional mode is usually implemented in devices that are likely to be used in professional recording environments, whereas the consumer mode is commonly implemented on equipment designed for home use in the consumer market. The primary difference between the two modes is in the implementation of the SCMS copy protection bit, which, in the consumer format, prevents the user from making digital copies of a digital copy. In most professional equipment, this copy-protection bit can be turned off or on according to the user’s needs. In consumer products, the SCMS bit is always enabled.
Unfortunately there is no way for the transmitting device to automatically detect which format the receiving device is able to accept. If you have a DAT deck that is not able to read the S/PDIF output from your AudioFire, chances are it is transmitting in the mode that the deck is not equipped to handle.
We have provided a software switch in the driver that allows you to select which mode AudioFire 8 transmits. To access this switch go to the console. Click on the
Settings tab. In the window that appears you’ll see a pair of radio buttons in an area labeled S/PDIF Format; one radio button is labeled Consumer and the other
Professional. Select the appropriate format for your DAT (if you don’t know which one to use, simply select the one that is not currently checked). Now click the Close button and again try recording to your DAT.
Note: AudioFire never transmits the SCMS bit; regardless of which mode is selected.
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Appendix A: Troubleshooting Guide
Appendix A: Troubleshooting Guide
Problem: When you play an audio file, it plays at an altered pitch.
Solution: When your AudioFire product is set to synchronize with an external device, it will play back at the rate generated by that device. For example, if the sound you are playing was sampled at 44.1kHz, but you are synchronized with a device running at 96kHz, the sound will play back at this faster rate. You have four choices - ignore the altered pitch, switch to your AudioFire product’s internal clock, change the sample rate of the external device, or use a different device for the sound playback.
Problem: Your AudioFire product doesn’t seem to recognize the synchronization clock to which it is connected.
Solution: Although it may seem obvious, the first thing to check is that there is a physical connection between the device generating the clock and your AudioFire product. Just because multiple devices are connected to the same computer doesn’t mean they are synchronized. Next, be sure that you have selected the desired input clock source in the Console for your AudioFire product and that the sample rate matches the incoming clock.
Problem: You’re syncing to an external device and suddenly you’ve lost sync.
Solution: Whenever your AudioFire product is syncing to an external device and you change the sample rate in that device, you may need to reset the input clock setting in the AudioFire Console software. Just click on the appropriate input clock button to reset it.
Problem: Recordings made using the S/PDIF input contain occasional pops or skips.
Solution: When recording with the S/PDIF input, you must manually select the
S/PDIF clock as the input clock. This can be done from the console.
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Appendix A: Troubleshooting Guide
Appendix A: Troubleshooting Guide
Problem: The sound cuts in and out, or the left or right channel doesn’t work.
Solution: You may have a bad audio cable. Try using a different cable in the problem channel.
Problem: There is no sound unless I pull the audio plug out a little.
Solution: Not all ¼” plugs are made to the exact same dimensions. Try a plug/cable from a different manufacturer.
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Appendix A: Troubleshooting Guide
Appendix B: An Introduction to Digital Recording
Appendix B: An Introduction to Digital Recording
Converting Sound into Numbers
In a digital recording system, sound is represented as a series of numbers, with each number representing the voltage, or amplitude, of a sound wave at a particular moment in time. The numbers are generated by an analog-to-digital converter, or
ADC, which converts the signal from an analog audio source (such as a guitar or a microphone) connected to its input into numbers. The ADC reads the input signal several thousand times a second, and outputs a number based on the input that is read. This number is called a sample. The number of samples taken per second is called the sample rate.
On playback, the process happens in reverse: The series of numbers is played back through a digital-to-analog converter, or DAC, which converts the numbers back into an analog signal. This signal can then be sent to an amplifier and speakers for listening.
In computers, binary numbers are used to store the values that make up the samples. Only two characters, 1 and 0, are used. The value of a character depends on its place in the number, just as in the familiar decimal system. Here are a few binary/decimal equivalents:
BINARY DECIMAL
0000000000000000 0
0000000000000001 1
0000000000000011 3
0000000000000111 7
0000000000001111 15
0000000000011111 31
1111111111111111 65,535
Figure A. Binary numbers and their decimal equivalents
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Appendix B: An Introduction to Digital Recording
Appendix B: An Introduction to Digital Recording
Each digit in the number is called a bit. The binary numbers expressed in Figure A are sixteen bits long, and have a maximum value of 65,535. The more bits that are used to store the sampled value, the more closely it will represent the source signal.
In a 16-bit system, there are 65,535 possible combinations of zeroes and ones; so
65,535 different voltages can be digitally represented. (See Figure A above).
Figure B. The more bits there are available, the more accurate the representation of the signal and the greater the dynamic range.
Your Echo product’s analog inputs use 24-bit ADCs, which means that the incoming signal can be represented by any of over 16 million possible values. The output DACs are also 24-bit; again, over 16 million values are possible. The
S/PDIF inputs and outputs also support signals with up to 24-bit resolution. Your
Echo product processes signals internally with 24-bit resolution to insure that there is no degradation to the audio signal as it is processed through the system.
The number of bits available also determines the potential dynamic range of the device. Moving a binary number one space to the left will multiply the value by two, so each additional bit doubles the number of possible values that may be represented. Each doubling of the number of values provides 6dB of additional dynamic range (see decibel section below). So, a 24-bit system can theoretically provide 144dB of dynamic range (6dB times 24 bits = 144dB) versus a 16-bit system with a maximum dynamic range of only 96dB.
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Appendix B: An Introduction to Digital Recording
Appendix B: An Introduction to Digital Recording
Also important to the quality of a digital recording is the frequency with which the samples are stored, called the sample rate. In order for a waveform to be faithfully digitized, it must be sampled at a minimum of twice the highest frequency to be stored. Failure to sample frequently enough results in a kind of distortion called aliasing. (If you like technical issues, do some research on The Nyquist Theorem, which explains why this happens). In addition to aliasing, sampling too slowly will result in reduced high frequency reproduction. Your Echo product allows you to sample sound at up to 96,000 times per second (192,000 with AudioFire 12).
Once the waveform has been transformed into digital bits, it must be stored. When sampling in stereo at 96kHz using a 24-bit word size, the system has to accommodate 4,608,000 bits per second. In the past, storing this vast amount of data was problematic. Today, computer-based digital recording systems record the data directly to the computer’s hard disk. Today’s hard disks are capable of storing large amounts of data, though the performance of hard drives can vary substantially. The speed and size of your hard drive will be a major determining factor in how many tracks of audio you will be able to simultaneously record and playback.
Decibels
Audio signal levels are generally expressed in units called “decibels” which are abbreviated as “dB”. This is a “logarithmic” scale where each doubling of signal level is represented by an increase of 6dB. Therefore a signal of 6dB is twice as big as a 0dB signal and a signal of 12dB is four times as big as a 0dB signal.
Since digital audio signals are represented by binary data, each bit of audio information represents 6dB. A 16-bit number can represent a total range of 96dB and a 24-bit number can represent a total range of 144dB (6 times the number of bits). It’s much easier to say that one signal is 72dB less than another instead of saying it is 1/4096 the size of the other one. It also more accurately represents the way we hear sounds, since the smaller signal in the above example will still be audible and not appear to be only 1/4096 as loud when we listen to it.
Just as there are different types of degrees used to represent temperature
(Fahrenheit, Celsius, etc), there are different types of decibels used to represent the
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Appendix B: An Introduction to Digital Recording
Appendix B: An Introduction to Digital Recording
level of analog audio signals. The most common are dBu and dBV decibels. Both of these represent voltage levels and still double for every increase of 6dB. It is only the reference point, or 0dB level that is different. A 0dBV signal has a voltage level of 1.0 volts. A 0dBu signal has a voltage level of .775 volts. Since .775 is approximately 2dB less than 1.0, converting dBV levels into dBu levels is as simple as subtracting 2dB (2.21 to be exact).
Signals are also occasionally represented with units of dBm. This is an older unit that measures power instead of voltage levels with 0dBm representing 1 milliwatt.
Earlier tube-based audio equipment used standardized input and output impedances of 600 ohms, so a 0dBm signal was produced with a voltage of .775 volts. Since most of today’s equipment uses impedances other than 600 ohms, it is more useful to represent signals by voltages rather than power and the dBu unit was introduced.
A signal level of 0dBu is identical to a level of 0dBm.
Digital signals, after they are recorded, no longer directly represent any physical quantity such as voltage or power and 0dB is generally used to represent a “fullscale” or maximum signal level. All other signal levels are lower and are expressed as negative decibels. Most meters on digital equipment have 0dB at the top and range downward from there. A signal that is 30dB below full scale would simply be referred to as a –30dB signal.
Nominal Signal Levels and Headroom
Today’s equipment is generally referred to as +4dBu equipment (professional) or
–10dBV equipment (consumer). These levels are the typical or “nominal” signal levels you can expect to see with professional (studio) equipment such as mixers or with consumer equipment such as home stereos and CD players. A +4dBu signal has a voltage level of 1.23 volts and a –10dBV signal has a voltage level of .316 volts.
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Appendix B: An Introduction to Digital Recording
Appendix B: An Introduction to Digital Recording
The above nominal levels represent typical or average levels that are often exceeded when recording loud signals such as drum beats. The difference between the nominal level and the loudest signal that can be recorded without clipping is called “headroom”. Your Echo product provides approximately 14dB of headroom allowing an 18dBu signal to be recorded.
Unbalanced and Balanced Inputs and Outputs
An unbalanced signal, commonly used for guitars and consumer electronics, contains two components, a ground signal and a “hot” or active signal. The ground is the barrel of a ¼” connector and the shell of an “RCA” style connector.
A balanced signal contains two active signals instead of one in addition to the ground. These are referred to as the “plus” and “minus” signals. A balanced input amplifier amplifies the difference between these two signals. Any extraneous noise picked up from power lines or other sources will appear equally on both the plus and minus inputs. This is called “common mode” noise since it is common to both signals and the input amplifier will subtract the noise on the minus input from the noise on the plus input.
If the input amplifier is perfectly balanced and the noise on both plus and minus is precisely equal, the noise will completely cancel out. In the real world this is not the case and some of the common mode noise will still make it through, although at a much reduced level. How well an input amplifier rejects this common mode noise is called the “common mode rejection ratio” (abbreviated as CMRR) and is expressed in dB.
Balanced outputs typically drive the plus and minus components of a balanced signal in one of two ways. A “differentially” balanced output signal is one where the minus output is the mirror image of the plus output. That is, if the “plus” output is at +1 volt, then the “minus” output is at –1 volt.
An “impedance” balanced output provides most of the benefits of a differentially balanced output at a lower cost. In this case only the plus component actually carries the signal. The minus component is tied to ground through a resistor so that the output impedance matches that of the plus component. Since the impedances
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Appendix B: An Introduction to Digital Recording
Appendix B: An Introduction to Digital Recording
are matched, any noise added to the minus component will still be approximately the same as that picked up by the plus component and will be subtracted out by the input amplifier. Your Echo product uses this type of output.
Balanced signals connect with either XLR connectors or TRS (tip, ring, sleeve) connectors. Your Echo product uses XLR connectors for microphones and TRS connectors for connecting balanced (and unbalanced) line level signals.
The three sections of a TRS connector are used to transmit the three components of a balanced signal (T = plus, R = minus, S = ground).
Dynamic Range
Dynamic range represents the difference between the maximum signal that can be recorded and the “noise floor”, or level of noise with no signal present. A system with a high dynamic range will be quieter than one with a lower dynamic range.
Dynamic range is a very important specification, and your echo product uses converters that have very high dynamic range.
Theoretically, a 24-bit system has a dynamic range of 144dB and a 16-bit system has a dynamic range of 96dB. Two questions immediately come to mind:
1) Why does my Echo product only have a dynamic range of 110 to 114dB?
2) For mastering 16-bit CDs with a dynamic range of 96dB, isn’t anything more than 96dB just overkill?
First, today’s analog-to-digital converters typically produce a full-scale input voltage with an input of +7dBu. If they were to have 144dB of dynamic range, they would have to be capable of resolving signals as small as –137dBu (7dBu –
144dBu) or approximately 10 nano-volts. That’s 10 one-billionths of a volt!
Transistors and resistors produce noise in this range just by having electrons moving around due to heat. Even if the converters could be perfectly designed to
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Appendix B: An Introduction to Digital Recording
Appendix B: An Introduction to Digital Recording
read these levels, the low noise requirements of the surrounding circuitry such as power supplies and amplifiers would be so stringent that they would either be impossible or too expensive to build.
In answering the second question, consider the fact that music is often compressed or amplified after it is recorded, and that some headroom is necessary when recording to avoid clipping. The only way that 96dB would be adequate is if all music were recorded so that the peaks were just under full-scale and no compression or amplification was going to be applied after recording. Any time recorded music is amplified, so is the noise at the low end. Your Echo product has enough dynamic range to allow sufficient headroom and post-processing to be applied while still keeping the noise either off the recording completely or down as far as possible.
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Appendix B: An Introduction to Digital Recording
Index
Index
A
ADAT.............................................. 39 adjusting playback levels ................ 32 analog-to-digital converter.............. 48
B
balanced........................................... 52
C
CD-ROM contents ............................ 9 clock settings................................... 35 console sessions .............................. 38 consumer mode ............................... 45 contacting customer service ............ 43 contents ............................................. 9
D
decibels............................................ 50 digital data....................................... 50 digital recording .............................. 48 digital-to-analog converter.............. 48 dynamic range ................................. 53
E
Echo Console .................................. 26
I
input level meters ............................ 18 input trims ....................................... 18 installation ....................................... 12
M
microphone preamp .........................17
MIDI ................................................20
MIDI time code......................... 20, 22
MTC.......................................... 20, 22
P
phantom power ................................17 professional mode............................45
S
S/PDIF .................... 19, 21, 40, 45, 46 safety instructions ..............................3 sample rate .......................................48
SCMS copy-protection ....................45 stand-alone mode .............................38 synchronization......................... 39, 46 synchronizing multiple devices .......39 system requirements ........................10
T
technical support..............................43 troubleshooting guide ......................44
TRS ..................................................53
U
unbalanced .......................................52
W
website .............................................43
Word clock................................ 22, 39
54
Index
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