for Audio - American Radio History
THE SOUND ENGINEERING MAGAZINE
JUNE 1975
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IN THIS ISSUE:
Audio in San Francisco
for Audio
Square Wave Generator
Speed?
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Why
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20. The Audio Cyclopedia (2nd ed.). Dr.
Howard M. Tremaine. New and updated,
here is the complete audio reference library in a single volume. It provides the
most comprehensive information on every
aspect of the audio art. This new edition
includes the latest audio developments including the most recent solid -state systems and integrated circuits. It covers all
subjects in the fields of acoustics, recording, and reproduction with more than 3400
related topics. Each topic can be instantly
located by a unique index and reference
system. More than 1600 illustrations and
schematics help make complicated topics
masterpieces of clarity. 1760 pages, 61/2 x
$34.00
9% hardbound.
1. The Technique of the Sound Studio.
Alec Nisbett. This is a handbook on radio
and recording techniques, but the principles described are equally applicable to
film and television sound. 264 pages; 60
diagrams; glossary. indexed; 51/2 x 81/2;
$14.50
clothbound.
13. Acoustic Design & Noise Control.
Michael Rettinger. 1973. NEW. revised
and enlarged edition covers physics of
sound, room acoustics and design, noise
and noise reduction, plus noise and its
problems. Many charts and graphs. A
practical and useful book. 562 pgs. $22.50
16. Magnetic Recording. Charles E. Lowman. Reference guide to the technology
of magnetic recorders used in audio recording, broadcast and closed- circuit TV,
instrument recording, and computer data
systems. Includes latest information on
cassette and cartridge recorders; TV recorders; direct and FM signal electronics
from low to wideband; servo -control and
signal record /playback circuitry; capstan.
reel, and head -drum servos for longitudinal, rotary, helical -scan, and disc recorders. Glossary, index, bibliographical
information, 274 pp.
$17.50
28. Environmental Acoustics. Leslie L.
Doelle. Applied acoustics for those in environmental noise control who lack specialized acoustical training. Basic information in comprehensible and practical form
for solving straightforward problems. Explains fundamental concepts; pure theory
minimized. Practical applications stressed,
acoustical properties of materials and
construction listed, actual installations with
photos and drawings. Appendixes illustrate
details of 53 wall types and 32 floor plans
$21.75
and other useful data. 246 pgs.
39. Reference Data for Radio Engineers.
ITT Stall. 5th Ed. The latest of one of the
most popular reference books for radio
and electronics engineers as well as libraries and schools. Complete, comprehensive reference material with tables, formulas, standards and circuit information.
Contains 45 chapters. 1196 pages with
hundreds of charts, nomographs, diagrams,
curves, tables and illustrations. Covers
new data on micro -miniature electronics,
switching networks. quantum electronics,
etc.
$20.03
24. Basic Electronic Instrument Handbook.
Edited by Clyde F. Coombs, Jr. Hewlett Packard Co. A basic reference background
for all instruments. Offers saving in time
and effort by having complete information
in one volume on how to get the most benefit from available devices. how to buy the
best instrument for specific needs. Reduces chances of costly errors. Ideal reference book, it is an excellent source for
the beginner. technician. the non -electrical
engineering man, or general non -engineering scientific and technical personnel.
800 pages. Hardbound.
$29.50
25. Operational Amplifiers- Design and Ap-
plications. Burr -Brown Research Corp.
A comprehensive new work devoted entirely to every aspect of selection, use, and
design of op amps -from basic theory to
specific applications. Circuit design techniques including i.c. op amps. Applicatons cover linear and non -linear circuits,
A/D conversion techniques, active filters,
signal generation, modulation and demodulation. Complete test circuits and
methods. 474 pages.
$18.00
Beranek. Designed
for the engineer with no special training
in acoustics. this practical text on noise
control treats the nature of sound and its
measurement, fundamentals of noise control, criteria. and case histories. Covers
advanced topics in the field. 1960. 752 pp.
33. Noise Reduction.
ßocase
As a service to our readers we are pleased to
offer books from prominent technical publishers. All prices listed are the publishers'
net. Shipping charges are included.
$26.00
32. Circuit Design for Audio, AM /FM, and
TV. Texas Instruments, Texas Instruments
To order use the coupon below. Indicate
quantity on the special instructions line if
more than one copy of a title Is wanted. Full
payment must accompany your order. We
Electronics Series. Discusses the latest
advances in design and application which
represent the results of several years research and development by TI communications applications engineers. Emphasizes time- and cost -saving procedures.
1967. 352 pp.
cannot ship c.o.d. Checks or money orders
should be made payable to Sagamore Publishing Company, Inc. Because of the time
required to process orders, allow several
weeks for the receipt of books.
$18.00
Electronics. Hibbard. A
Basic Course for Engineers and Technicians. An extremely practical reference
book for anyone who wants to acquire a
good but general understanding of semiconductor principles. Features questions
and answers, problems to solve. 1968.
169 pp.
$10.25
31. Solid -State
Sagamore Publishing Company, Inc.
1120 Old Country Road,
Plainview, N.Y. 11803
Please send me the books have circled
below. My full remittance in the amount
is enclosed. N.Y. State resiof $
dents add 7% sales tax.
1
1
Alphabetical Guide to Motion
Picture, Television, and Videotape Productions. Levitan. This all- inclusive, authoritative, and profusely illustrated encyclopedia is a practical source of information about techniques of all kinds used
for making and processing film and t.v.
presentations. Gives full technical information on materials and equipment. processes
and techniques, lighting, color balance,
special effects. animation procedures,
lenses and filters, high -speed photog35. An
raphy. etc. 1970. 480 pp.
$24.50
40. Radio Transmitters. Gray and Graham.
Provides, in a logical, easy -to- understand
manner, a working knowledge of radio
transmitters for quick solution of problems in operation and maintenance. 1961.
$17.50
462 pp.
37.
Television Broadcasting: Systems
Maintenance. Harold E. Ennes. Covers
maintenance of the t.v. broadcasting system from switcher inputs to antenna.
Theory and operation of systems, tests
and measurements, including proof of
performance for both visual and aural
portions of the installation. Many illustrations. A thorough treatment of modern
television maintenance practice. 624 pgs.
$16.95
41. Modern Sound Reproduction. Harry
F. Olson. A basic text covers amplifiers,
microphones, loudspeakers, earphones,
tape systems. film sound, tv and sound
reinforcement
the significant elements
and systems of modern sound reproduction. Employs simple physical explanations which are easily understood without special engineering training. Highly
recommended text and reference. 328
-
pages.
$18.50
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Canada and foreign. Add $1.00 per book
38. Television Broadcasting:
Equipment,
Systems, and Operating Fundamentals.
Harold E. Ennes. An extensive text covering fundamentals of the entire television
broadcast system. Excellent for new technicians and operators and as a source of
valuable reference data for practicing technicians. Discusses NTSC color systems,
camera chains, sync generators, recording systems, mobile and remote telecasts,
t.v. antenna systems. Tables, glossary, exercises and answers. 656 pgs.
$16.95
26. The Design of Digital Systems. John
B. Peatman.
Textbook for students desir-
ing to develop a creative approach to design capability through a digital systems
approach. Answers these questions: Under what circumstances it is desirable to
implement a system digitally? What are
some of the components available for
implementing the system? How do we go
about designing it? 448 pages.
$17.50
LOU BURROUGHS
If you work with
microphones,
you need this book!
r
't '~
ISBN
LC #73 -87056
#0- 914130-00-5
'._...
^¡,.
The most important
THE AUTHOR
microphone book
ever published.
Holder of twenty -three patents on electro-acoustic products,
Lou Burroughs has been responsible for extensive contributions in the development of the microphone. During World
War II, he developed the first noise cancelling (differential)
microphone, known as the model T -45. Used by the Army
Signal Corps, this achievement was cited by the Secretary of
War. Burroughs was the creator of acoustalloy, a non -metallic
sheet from which dynamic diaphragms are molded. This material made it possible to produce the first wide -range uniform- response dynamic microphone. Burroughs participated
in the design and development of a number of the microphones which have made modern broadcasting possible - the
first one -inch diameter wide-range dynamic for tv use; the
first lavalier; the first cardiline microphone (which ultimately
won a Motion Picture Academy award) and the first variable D dynamic cardioid microphone. He also developed the rust
wind screens to use polyester foam. Burroughs was one of the
two original founders of Electro- Voice, Inc. He is a charter
member of the Society of Broadcast Engineers and a Fellow
member of the Audio Engineering Society.
A practical, non -theoretical reference manual for those
involved in the application of microphones for tv, motion
pictures, recording and sound reinforcement.
At last, the practical aspects of microphone design and
application have been prepared and explained in one
concise, fact- filled volume by one of audio's outstanding
experts. This book is so full of useful information, we think
you'll use it every time you face a new or unusual
microphone problem.
Perfect for Reference or Trouble- shooting
The twenty -six fact -packed chapters in this indispensable
volume cover the field of microphones from physical
limitations, electro- acoustic limitations, maintenance and
evaluation to applications, accessories and associated
equipment. Each section is crammed with experience- tested
you
detailed information. Whatever your audio specialty
need this book!
r
ORDER FORM
Sagamore Publishing Co., Inc.
1120 Old Country Road, Plainview, N.Y. 11803
Along with down -to -earth advice on trouble -free
microphone applications, author Lou Burroughs passes on
dozens of invaluable secrets learned through his many years
of experience.
He solves the practical problems you meet in day -to -day
situations. For example:
j copies of MICROPHONES: DESIGN AND
APPLICATION at 820.00 each.
Please send j
Name
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* When would you choose a cardioid, omni -directional, or
bi- directional mic?
* How are omni -directional mics used for orchestral pickup?
* How does dirt in the microphone rob you of response?
* How do you space your microphones to bring out the best in
each performer?
This text is highly recommended as a teaching tool and
reference for all those in the audio industry. Price: $20.00
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Sensurround, an illusion of motion
through carefully contrived sound vibrations, made news in the motion
picture, Earthquake. Meryl Altman's
article EARTHQUAKE -A MOVING EXPERIENCE, tells the inside story.
THE SOUND ENGINEERING MAGAZINE
JUNE 1975, VOLUME 9, NUMBER
The engineer who always seems to
have an answer to sudden ticklish
problems, doesn't carry a magic wand.
He owns one of Don Davis' HANDY
BLACK BOXES. Mr. Davis describes
the indispensible little items which
every audio engineer should keep in
his box, ready for instant use.
26
A British look at the ELECTRET
32
contribution of
Basil Lane, assistant editor of Wireless
World. Mr. Lane describes the principle behind the permanently charged
dielectric and other technical details
of this miniaturized capacitor mic.
MICROPHONE is the
Bonus db reprint brings back David
L. Klepper's ARCHITECTURAL ACOUSTICS, PART 2, which many readers
have requested for its clear instructions in designing studios to meet specific needs.
16
34
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4
6
9
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12
14
20
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6
LASERIUM -LIGHT WITH MUSIC
Martin Dickstein
HOW AUDIO IS DOING IN SAN FRANCISCO
Stephen Lampen
COVERS AUDIO BAND IN ONE SWEEP
James Davidson
ARCHITECTURAL ACOUSTICS -PART
David Klepper (Reprint)
WHY USE 15 IPS TAPE SPEED?
Josef Dorner
RECORDING STUDIO ACOUSTICS -PART 6
Michael Rettinger
1
LETTERS
INDEX OF ADVERTISERS
CALENDAR
FREE LITERATURE
THE SYNC TRACK
John Woram
THEORY AND PRACTICE
Norman H. Crowhurst
SOUND WITH IMAGES
Martin Dickstein
NEW PRODUCTS AND SERVICES
CLASSIFIED
PEOPLE, PLACES, HAPPENINGS
db is listed in Current Contents: Engineering and Technolog
Robert Bach
PUBLISHER
Larry Zide
EDITOR
Bob Laurie
ART DIRECTOR
All of the recording studios shown
here were photographed by Stephen
Lampen for his article on audio in
San Francisco (p. 26). Represented
in this colorful montage are: Record
Plant, His Master's Wheels, Columbia, Freeway Recording, Fantasy Records, Coast, Sierra Sound, Different
Fur, and Wally Heider's.
Eloise Beach
Alex Porianda
MANAGING EDITOR
John Woram
ASSOCIATE EDITOR
Hazel Krantz
COPY EDITOR
Ann Russell
PRODUCTION
CIRCULATION MANAGER
GRAPHICS Crescent Art Service
db. the Sound Engineering Magazine is published monthly by Sagamore Publishing Company, Inc. Entire
contents copyright © 1975 by Sagamore Publishing Co:, Inc., 1120 Old Country Road, Plainview, L.I., N.Y.
11803. Telephone (516) 433 6530. db is published for those individuals and firms in professional audio recording, broadcast. audio -visual, sound reinforcement, consultants, video recording. film sound, etc. Application should be made on the subscription form in the rear of each issue. Subscriptions are $6.00 per year
($12.00 per year outside U. S. Possessions, Canada, and Mexico) in U. S. funds. Single copies are 51.00
each. Controlled Circulation postage paid at Harrisburg, Pa. 17105. Editorial, Publishing, and Sales Offices:
1120 Old Country Road, Plainview, New York 11803. Postmaster: Form 3579 should be sent to above address.
letteis
ACTIVE EQUALIZERS
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THE EDITOR:
FEATURES
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Equal Q in both boost and cut
Magnetically shielded for low hum
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"
"
Variable low frequency cut
No insertion loss
All negative feedback for highly linear
and stable operation
Low noise
Dual outputs with plug -in networks for
bi -amp option.
Size:
3'h"
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8'/z" deep
Sound Fie. inf
ment Model -Security Cover
Rack Mounting
Transformer Coupled Input
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Phono Type Connectors
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GEORGE W. HAMILTON
(SYRACUSE UNIVERSITY,
BEIRUT, LEBANON
CIII
STL magnetic Test Tapes
are the Most Comprehensive
We offer precision magnetic
in the World
test tapes made on precision
equipment for specific jobs in 1" and 2" sizes as well as
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When you use STL test tapes you combine interchangeability with compatibility. You know you are using what
other leaders in the professional recording, equipment
manufacturing, government and educational agencies
throughout the world are using.
Make sure your system is in step with the rest of the industry.
Wri e for a free brochure and the dealer in your area.
Dis ributed exclusively by Taber Manufacturing & Engineering Co.
T
Reference the article appearing in
your January issue, audio certainly did
get a big boost at Syracuse, thanks to
the Newhouse publishing interests and
the attention lavished on the Newhouse Communications Center. How
times have changed!
I was Student Chief Engineer at
the University's WAER from 19501953. The station had just increased
power from 21/2 watts (that's right!
This was the forerunner of the 10watt educational stations) to 1 kW.
Remote recordings were made -in
mono, of course-on reluctant Pen trons, and bulky two- unit-plus -powersupply PT6H Magnecorders were considered state -of- the -art. The poor engineer headed off to do a remote
sports or music broadcast had to haul
fifty or sixty pounds of remote box,
power cable, mikes and all the rest.
Home -built mixing consoles, "adapted" disc recording amplifiers and the
like notwithstanding, the radio -tv center turned out some remarkable work
and some first -class professional broadcasters. With all of that wealth of
new equipment to play with, let's hope
that the students of today remember
that it's the product. and not the
means, that counts.
STANDARD TAPE LABORATORY, Inc.
2081 Edson Avenue
San Leandro, CA 94577
(415) 635-3805
'53/54)
THE EDITOR:
Martin Dickstein's February column
was most enjoyable.
However, he incorrectly describes
the method used for getting sound of
Fibber McGee's closet.
Fibber McGee and Mollie was originated from WLW in Cincinnati.
On a tour of the station as a high
school student in the mid -50's, I was
shown the actual "closet." It was a
wooden box, about 7 or 8 feet tall by
3 or 4 feet square. Inside were hinged
shelves on which items were placed.
The sound man would trip the shelves,
causing the items to drop. A mic was
placed in front of the closet; it did
not have a solid door, but one made
of slats to allow the sound to get to
the mic.
Thanks for constantly producing a
very interesting magazine.
RICHARD GOOD
ADM INISTRATIVE VICE PRESIDENT
COLUMBIA SCHOOL OF BROADCASTING
SAN FRANCISCO, CA.
(V
Circle 13 on Reader Service Card
www.americanradiohistory.com
Our new E series audio equipment will
improve your sound and cut your
costs . . . or your money back!
I
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MP-8E Mono $86
5P -8E Stereo $137
MIC & LINE AMPLIFIERS
Dual function and superb performance. Inputs for
mic and line, 4-0.5db response 10Hz.20KHz, 67db
gain on mic channel(s) +26db gain on line inputs.
Balanced inputs & outputs, +21dbm out max, 0.1%
distortion. Internal power supply.
MLA -1E Mono $98
MLA-2E Dual Mono /Stereo $139
AUDIO DISTRIBUTION AMPLIFIERS
From 1 in /6 out to 20 in /BO out in one small package. Whatever your distribution requirements we
have an answer. All units meet or exceed the following specifications: Balanced bridging /matching
inputs, balanced 600ohm outputs, ±0.5db response 10Hz- 20KHz, 4-3db 5Hz- 40KHz, 26db gain,
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down referenced to +21dbm out.
supplies.
DA-6/E
DA-6R/E
DA-6BR/E
DA -6RS /E
DA- 16BR /E
Table top. 1 in /6 out.
$131
Rack mount. 1 in /6 out.
$149
Rack mount. 1 in /6 out.
Individual
level controls for each output.
$165
Rack mount. 1 in /6 out stereo or 2
in /12 out mono.
$229
Rack mount. 1 in /8 out stereo or 2
in /16
DA- 2080/E
Internal power
out mono. Individual output
level controls, selectable metering &
headphone monitoring.
$287
Rack mount main frame with protected
DA- 2080/E
DA- 2080 /E
power supply, metering & headphone
monitor. Will accept up to 10 slide in
modules. Each module has 2 inputs
& 8 outputs. Individual output level
controls & selectable meter switch. Up
to 20 in /80 out.
Main Frame
$150
Modules 2 in /8 out
$135 ea.
AUDIO CONSOLES & CONTROLLERS
Our new series 35 audio controller introduces a
new concept in audio mixing. Allows separation of
controls from the audio functions. Controls can be
placed in any convenient location in the studio,
while electronics may be mounted anywhere for
easy maintenance & hookup. Remote DC control
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This versatility gives you a custom designed console at a standard production model cost.
Features include; 8 channels, mono, dual channel
mono, stereo, dual channel stereo, or combinations; paralleling 2 units for quad, fail safe power
supply & plug in interchangeable cards.
Performance specifications are; 0.3% or less distortion, 124dbm equivalent noise on low level channels, approximately 25w power consumption,
-70db crosstalk, balanced bridging /matching inputs & response within 4-2db 20Hz- 20KHz. Series
35 audio controllers start at $1200.
AUTOMATIC TAPE CARTRIDGE AND CASSETTE
LOADERS
So easy to use & accurate that our largest winder
competitor has been using one of these to load
their own carts.
Eliminates guesswork. Set the dials to the length
desired. The exact amount of tape is fed onto the
cart or cassette hub and then shuts off automatically. Also has exclusive torque control for proper
tape pack on different size hubs. Winds at 30 IPS.
ACL -25/E
$185
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Winders also come in higher speed models (ACL 60 series). Same operation as above but winds at
60 IPS. Accepts 14" pancakes.
(tone stop only)
ACL-60T /E
$266
ACL -60B /E
(Blank tape loader)
$331
ACL- 608T /E (for both prerecorded and
blank tape)
$375
STUDIO MONITOR AMPLIFIERS
Exceptional reproduction! Internal muting. ±2db
response from 20Hz- 40KHz. 25w music power, 20w
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Distortion less than 0.25% at less than 20w out,
1% or less at 20w. Works into 4.16ohms. Balanced
bridging inputs, variable bass contour, internal overload & short circuit protection.
SMA-50/E
Table top (mono)
$125
SMA-500/E
Rack mount (mono)
$142
SMA- 1000 /E Rack mount (stereo -40w)
$196
REMOTE POWER CONTROLLERS
Safe, transient free means of
(DUAL)
controlling 110V /AC.
Turntables, on the air lights, etc.
PR-2
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PR -28 (momentary contact actuation)
$39
$54
Give us a call or write today for further details.
You'll be money and performance ahead.
CALL COLLECT
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(916) 392 -2100
3516 -C LaCrande Boulevard
Sacramento, California 95823
RAMKO RESEARCH
AUDIOWAVES
The perfect beginning.
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Sound decisions start with a
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See your RCA representative.
It could be the perfect beginning of
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Automation Systems
Amplifiers and Speakers
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The best by far...
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MXR Innovations
Neumann
Rupert Neve
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Philips Audio (AKG)
Polyline
Precision Electronics
Ramko Research
Rauland -Borg
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Revox
RIA Tapes
Sescom
Sound Genesis
Southwest Technical Products
Standard Tape Labs
TEAC Corp. of America
Telefunken
Timekeeper
White Instruments
Woram Audio
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(miking
a drum set or other instruments
which greater separation is required, the
C -414 has a hyper -cardioid pattern (in addition
to switchable cardioid, omni or figure- eight).
For a close range vocalist, brasses or other
sources generating high sound pressure levels, the
C -414 is capable of handling 124 dB SPL with less
than 1% distortion (THD of complete system, including capsule; whereas others specify preamp. only) and
if all else fails, the C -414 has a switchable 10 dB pad to
prevent overload of its own preamplifier and your inputs.
And to help you cope with dynamic range, the
C -414's
equivalent noise level is 21 dB (DIN 45405).
You can power it directly from your console (standard 24 v. B +).
It doesn't require a special card. It's also fully compatible with
the popular AKG C -451E. Both were designed to make you
happy.
The C -414 will live up to your standards. Contact your
professional equipment supplier or write directly to us.
AKG MICROPHONES HEADPHONES
PHILIPS AUDIO VIDEO SYSTEMS CORP.
AUDIO DIVISION
91 McKee Drive, Mahwah, N.J. 07430
A North American Philips Company
The AKG C-414
It's all a matter of
professional
judgment.
n
Circle 17 on Reader Service Card
www.americanradiohistory.com
CALENDAR
JUNE
Brigham Young University
Audio Recording Technology
Course. Contact: Russel Peterson, Brigham Young University, Audio Recording Technology Course, 242 Herald R.
Clark Building, Provo, Utah
84602. Phone: (801) 374 -1211,
ext. 3784.
15 -18 AMTEC '75, Canadian Educational Communications Conference of the Association for
Media and Technology in Education, Calgary. Alberta, Canada. Contact: Garry Smith,
ACCESS Television South, Calgary Health Sciences Centre,
1611 29th St. N.W., Calgary,
Alberta T2N 418.
9 -27
JULY
-Core
Cwv) ClearInIman
fyAery
(415) 989 -1130
Datable
Circle 18 on Reader Service Card
THE NAME
AND THE
PRODUCT
THAT
sets the
an
Nashville Audio Exhibition seminar. Contact: Nashville Audio
Exhibition, P.O. Box 12123,
Nashville, Tenn. 37212. (615)
327 -3918.
8 -11 INTER NAVEX '75 (Audio
Visual Aids in Education)
London.
7 -11
A division of Lumiere Productions
759 Harrison Street, San Francisco, Ca. 94107
ar
SEPTEMBER
NOISE- CON'75National Conference on Noise Control Engineering. Gaithersburg. Md.
Pre -seminar at the Shoreham
Hotel. Washington, D.C. Sept.
11 -13. Contact (914) 462 -6719.
28SMPTE Technical Conference
Oct. 3 and Equipment Exhibit. Century Plaza Hotel, Los Angeles.
Contact: SMPTE Conference.
862 Scarsdale Ave., Scarsdale,
N.Y. 10583.
29 -30 N.Y. Chapter of ERA, Commercial Sound & Communications Show, Statler -Hilton
Hotel, New York City. Contact: GIM Sales Corp., 375 N.
Broadway, Jericho, N.Y. 11753
(516) 433 -4080.
15 -17
or PA. euniument
Whatever your PA needs, from a small office to large auditorium,
with amplifiers in every power range, including mobile,
Precision Electronics delivers the product and value .
including an entire line of accessories. Get all the facts,
without obligation, on the "right sound" for your needs.
.
Complete and mail this coupon today.
NAME
COMPANY
ADDRESS
STATE
CITY
Mall to: PRECISION ELECTRONICS, INC.
9101 King St., Franklin Park, Illlnols 60131
ZIP
.
OCTOBER
21 -26
International Audio Festival
Fair. London. England. Contact: British Information Service, 845 Third Ave.. New
York, N.Y. 10022. (212) 7528400.
co
Circle 19 on Reader Service Card
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PHASING vs FLANGING
the discernible difference
Phaser: An effects component
designed to produce
a
Flanger: An effects component
created by MXR Innovations to
provide repeatable reel -flanging
effects, caused by mixing a dry
and a time delayed signal to
create a comb -filter response
with harmonically related corn -
phase -
shift response created by a
comb -filter effect with frequency- related notches which is
mixed back with the original
signal.
ponents.
The effect of flanging is created
by mixing a variable time delay
signal back with the original dry
signal. The resulting comb -filter
response is characterized by the
precise mathematical relation ship created by the time delay.
The effect of phasing is obtained
by passing the input signal
through a series of all -pass filters exhibiting a phase response
that is variable in frequency.
When this signal is mixed back
with the input signal, cancellations and reinforcements occur.
The resulting comb -filter effect
spreads over a wide range of
frequencies. As these notches
are moved up and down the
audio range, a spacious, spinning effect is obtained.
The subjective effect is that of
conventional reel -flanging,
without the necessity for manpower and multiple tapedecks
a costly and highly special ized digital delay system. The
comb- filter response of flanging
causes random program material (i.e. drums, cymbals and
other percussion) to take on
musical tonality. Unlike phas-
or
The subjective effect of phasing'
is best at mid and low frequency
ranges, as opposed to flanging,
phasing's chronological predecessor.
ing, flanging is subjectively
more noticeable at mid and
high frequencies, due to the
time delay created response.
Unlike reel -flanging, the MXR
Auto Flanger is at the tip of your
fingers in real time.
You will find the Auto Flanger and Auto Phaser to be wise additions to any studio effects board.
Compact and fully compatible with existing systems, both components are easily incorporated with the
mere addition of a simple power supply (+ 15 to + 30V).
Once installed, the units' ease of operation and versatility will revolutionize your effects board.
External control capabilities allow for stereo operation of two units, and low power consumption ensures multiple use without excessive drain on your board supply. Both units are durable, reliable,
affordable ... innovative -and are internationally available at leading audio supply houses.
rF
p.¡,
.d
v.---
MXR Innovations, Inc.
Professional Products Group, 277 N. Goodman St., Rochester, N.Y. 14607
Circle 20 on Reader Service Card
www.americanradiohistory.com
You'll find what you need
...for Tape Duplicating
(cassette, 8- track, open reel or
any combination) for music,
industry, education in the
Electro Sound line from
and
AUDIOMATIC CORPORATION
You'll find what you need
...for Tape Mastering, or
Studio Recording
(mono-14" to 8-track-1" or
any combination) in the ES 505
Pro Recorder line from
aloud
AUDIOMATIC CORPORATION
You'll find what you need
...for Quality Control
of pre- recorded pancakes
(cassette, quad. 8 -track or any
combination) in the
Electro Sound line from
AUDIOMATIC CORPORATION
\10
1290 AVENUE OF THE AMERICAS
NEWVORK.N V 10019. PHONE (2121582-4870
CABLE AUDIOMATIC /TELEX 12 -6419
OVERSEAS OFFICE: 4 RUE FICATIER
92400 COU RBEVOI E. F RANCE, PHONE 333.30 90
CABLE. AUDIOMATIC /TELEX. 62282
Circle 21 on Reader Service Card
www.americanradiohistory.com
FREE LITERATURE
To obtain the free literature described,
please circle the appropriate number on
the Reader Service Card in the back of
the magazine.
LOW -COST MINIATURIZED
POWER SUPPLIES
Engineering bulletin provides typical schematics and suggested components for construction of low-cost,
miniaturized, unregulated and regulated power supplies. Mfr: Microtran
Co., Inc.
Circle No. 80 on R.S. Card
OSHA's noise regulations are described, with charts, in this brochure.
Mfr: B & K Instruments.
Circle No. 87 on R.S. Card
X36 types of
empty tape reels
\\ and boxes
TRANSFORMERS, INDUCTORS,
POWER SUPPLIES
More than 30 categories of transformers, including autoformers, bridging, CRT power, driver, geoformer,
input and interstage are covered in
this 52 -page 1975 -6 "Catalog of
Transformers, Inductors, Power Supplies and Circuit Cards for Industry."
Mfr: Litton Industries (Triad -Utrad).
Circle No. 88 on R.S. Card
for hli -speed duplicating
tv spots
C1 audio spots -
IMMEDIATE SHIPMENT
FROM MANUFACTURER'S STOCK
GET CATALOG PD 175
Polyliñe
A
A 24 -page catalog containing about
350 heads with cross references for
equipment produced by most major
professional recorder manufacturers.
Mfr: Nortronics Co., Inc.
Circle No. 81 on R.S. Card
MARK
INTERFACING COS /MOS SYSTEMS
8 -page application note providing
examples of practical circuits for interfacing situations between COS/
MOS and other technologies. Mfr:
RCA.
Circle No. 82 on R.S. Card
CONNECTORS AND COMPONENTS
INSTRUCTIONAL VIDEO TAPES
A list of video tapes on technical
electronics subjects are included in this
24 -page 1975 catalog. Subjects include a tutorial series on transistor
theory, trouble- shooting solid -state circuits, and digital electronics. Some
available in languages other than
English. Mfr: Hewlett- Packard.
Circle No. 84 on R.S. Card
BI- MONTHLY NEWSLETTER
The Sibley News, a two -page news-
letter is published bi- monthly, reporting on printed circuit design, wiring,
production, or packaging. Mfr: The
Sibley Co.
Circle No. 85 on R.S. Card
-
312/298-5300
DesPlaines, IL 60016
Circle 22 on Reader Service Card
AUDIO HEAD REPLACEMENT GUIDE
Card edge connectors, p.c. varicon
receptacles, rack and panel receptacles, contact strips, and card enclosures are listed in this 32-page catalog. Mfr: C. Tennant Electronics.
Circle No. 83 on R.S. Card
CORP.
1241 Rand Rd.
ON THE
FOLLOWING
OF
QUALITY
PRODUCTS:
Reverberation Units
Studio Turntables and
Pickups
Compressors, limiters
and noise filters
Digital audio signal
delay units
Auditorium microphone
winch systems
Specialized tape
machines for endless
loop cassettes and
logging purposes
Electronic tuning fork
and polarity tester
Wow and flutter test
equipment
Outside the U.S.A. contact:
TECHNOLOGY
LOUDSPEAKER ENCLOSURES
A U D
"Loudspeaker Enclosures
Their
Design and Use," is a 32 -page publication aimed at those who wish to
build their own cabinets for raw
frame speakers. Mfr: Altec.
Circle No. 86 on R.S. Card
mbH.
FRANZLAHR
EMT-I
1520
P O
8
I
O
D
-7830
W. Germany
Cables: MESSTECHNIK LAHR
Phone: (07825) 512
Telex: 754319
OSHA NOISE COMPLIANCE
Equipment needed to comply with
CD
Circle 23 on Reader Service Card
www.americanradiohistory.com
sYnc
Archeologists tell us that many
years ago, recording engineers used a
device known as a tape delay system.
Usually, signals on their way to a reverberation chamber were first fed
through this auxiliary machine, so that
they were delayed a bit on their way
to the chamber.
The system worked, but was inflexible, noisy, and a nuisance. The
delay tape would run out in the middle of the ultimate mix, and the delay
time was either too long or too short,
depending on the speed of the machine. Today, all the beautiful people
are using digital delay lines. You feed
the signal into a black box where God
knows what is going on inside. A little while later, the signal pops out the
other end, none the worse for wear.
On the front of the black box are
some controls, and you simply dial
up the amount of delay you need.
That's all there is to it-no rewinding
of tape, no fiddling with a capstan to
get the delay you want. And no moving parts (except electrons).
The delay line is one of the first
applications of digital techniques in
audio. And now there are those new
tape recorders that confuse so many
of us with their logic systems. The
logic system knows more about what
you want to do than you do, and you
must never make it angry! It's usually
got a built -in fail /safe system, which is
the first thing to crap out. This means
that when you press "stop," the machine may perform the following functions:
1. Stop.
2. Go into record mode.
3. Go into fast forward.
4. All, or none, of the above.
Your maintenance department does
not want to hear about it, for there
are neither tubes to tap, nor pulleys
to pluck. There may not even be a
spring to snap. In short, the machine
is unfixable. Unless you know something about
°
DIGITAL TECHNIQUES IN AUDIO
This was the subject discussed recently at the 1975 Midwest Acoustics
Conference, a joint venture of the
Audio Engineering Society's Chicago
section, the Acoustical Society of
America, the Institute of Electrical
and Electronics Engineers, the Chicago Acoustical and Audio Group, and
Northwestern University. This year's
JOHN M. W
-or
-
conference President
Big Mac
was Bob Schulein of Shure Brothers,
who got things under way with a talk
by Dr. Barry Blesser on Digital Processing of Audio Signals. Dr. Blesser
gave us some idea of what digital
audio is all about.
Consider the problem of transmitting an infinite number of voltages,
lying between, say, zero and 5V. If
we have a 5V source available at a
we can transmit either 5V
switch,
or zero V, depending on the condition
of the switch. Not very promising, if
we wish to transmit any voltage between these two levels. If we add a
second switch, 5,,, which will supply
a voltage of 0.5S, = 2.5V, we now
have four choices. (5 + 2.5, 5, 2.5, 0).
With a third switch, S,. = 0.55,, _
1.25V, we have 8 choices. (5 + 2.5
S
+
1.25, 5 + 2.5, 5 + 1.25, 5, 2.5 +
1.25, 2.5, 1.25, 0). The number of
voltages available increases by the
square of the number of switches, so
the system's capability for transmitting
any desired voltage increases rapidly
as switches are added, while the error factor decreases just as quickly.
Since each switch is either on or off,
we can represent all possible combinations by a series of zeroes (off)
and ones (on). So what?
Well, if we pick some convenient
d.c. voltage that happens to be lying
around, we can transmit a series of
pulses, each of which represents a
"switch on" condition. No pulse
means either the system isn't working, or the switch is in the oft condiHon. To eliminate this ambiguity,
another voltage level is usually used
to signify zero. Now, at one end of
the transmission medium, the (analog) voltage to be transmitted is converted into a series of (digital) pulses.
At the other end, the pulses are converted back to the analog voltage they
represent, and the listener hears the
original program, since the voltages
we are talking about are of course,
audio signals.
The reason for bothering with this
analog /digital and digital /analog conversion process is that the digital data
can be stored and retrieved with
greater accuracy (and expense) than
the equivalent audio, or analog, information. Since the digital information
is a function of the audio signal only,
noise within the transmission medium
tape hiss and all that-does not get
converted into audio at the output end.
ECHO AND REVERB SYSTEMS
Following Dr. Blesser, Mahlon
Burkhard of Industrial Research Products, Inc. discussed the specific application of digital technology to echo
and reverberation systems. In either
application, the audio signal is converted to digital pulses, which are
stored in a memory system and reconverted to audio after a suitable
delay. Although well suited for the
creation of an audio echo or two, an
orderly repetition of many delays, t,
2t, 3t, 4t,
may not sound altogether convincing as a simulation of
...
reverberation. Natural reverberation
consists of an incredibly large number of echoes, occurring at apparently
random time intervals and at differing
amplitudes. As Mr. Burkhard pointed
out, a digital simulation of natural reverberation is still a costly process.
However, there may come a time
when the natural reverberation of an
auditorium may be measured and artificially reproduced with digital techniques and at a realistic price tag. But
not today.
DIGITAL FILTERING
Next, Thomas Curtis of Bell Telephone Laboratories spoke about digital filtering of audio signals. Or at
least I think he did, but the math was
way over my head, and I got lost almost at once. I think the point is that
once the information is in digital
form, it can be extensively modified
before being converted back to analog audio. Earlier, Dr. Blesser alluded
to various signal processing techniques that might be used digitally.
Of course, neither conventional filters
nor limiters will be usable in the digital world, so we may expect to see a
new generation of devices presumably offering great flexibility at a very
high price
least at first.
Lexicon's Francis Lee demonstrated
digital techniques applied to frequency
shifting. Over the years, there have
been many attempts at independently
varying the frequency or timing of a
program. Radio stations in particular
would love a gadget that would allow
them to speed up the last few minutes
of a long running program, without
raising the pitch. However, such devices still need a bit more development work. Speech remains intelligible, but music does not do well at
all. Mr. Lee successfully demonstrated
real time frequency shifting of his
-at
voice, as well as time compression
and expansion of previously recorded
material.
During the afternoon session, Thomas Stockham of the University of
Utah had originally planned to compare 24th generation digital and analog recordings. However, by the 17th
generation, the analog recording had
just about self-destructed, while the
24th digital was still of master quality. The conference's analog tape recorder, on which the final generations
had been recorded for comparison,
got a little temperamental- frightened
perhaps at its prospects for future survival. However, the conference cornmittee managed to get it back in
shape in time for Mr. Stockham to
make his point on the viability of digital recording, editing, and duplication.
Derek Tilsley, from the Neve home
office in England, gave us a behind the- scenes glimpse of his company's
research work with digital technology.
Neve engineers seem to be on the left
side of fanaticism when it comes to
noise figures, and haven't been satisfied with current automated mixdown
techniques.
Towards the end of the conference,
Motorola's Scalatron was described
and demonstrated. The Scalatron, a
digitally programable keyboard instrument, may be quickly tuned to any
scale with up to 24 steps per octave.
For more traditional tastes, the Scalatron may be tuned to say, a just tern pered scale, to hear how it all sounded
before Bach. And, transpositions can
be worked out with little pain.
COMPUTER -GENERATED MUSIC
In the final presentation, Joseph
Olive of Bell Telephone Labs discussed
computer-generated music. Mr. Olive
has been quite active in the area of
computer music, and brought along
several examples of his work.
One of the limitations of some
computer-generated music is that the
feedback loop between man and machine is broken. The composer must
prepare his computer program, which
the machines will digest. Some time
later, out comes the music. Spontaneity of expression and phrasing is lost
-pretty much like on a vocal over
dub session-unless the computer
works in real time, which may not be
possible when complex sounds are required.
Mr. Olive demonstrated some interesting effects, such as the tone that
seems to be continuously falling in
frequency, without actually doing so.
(If you weren't there, don't ask me to
explain it).
The grand finale was an excerpt
from an opera for soprano and computer. Our scientist -soprano begins
teaching the computer to speak. After
a while, she tires of the exercise and
turns the machine off. Or at least she
thinks she does. Too late! The computer has been romantically aroused,
and declares its affection for the scientist. Due no doubt to its digital
heart, the computer's readout has determined that the scientist is a woman
as well as a person. And she has discovered that it is a man as well as a
machine. (I wonder what women's lib
will do with this one ?)
In a rousing duet that sounds suspiciously like the Brindisi from La
Traviata, our hero and heroine pledge
eternal devotion and other non- technical stuff. Perhaps their first genera-
tion reproduction will combine the
best of analog and digital techniques.
But that's another opera.
DEPARTMENT OF CORRECTIONS
For many years, the April sync track
has been an april fool put on, as some
very perceptive readers may have suspected. But last April's wasn't, except for one line that told about current going from water pipes to a.c.
receptacle, via the grounding wire!! I
wouldn't recommend that anybody try
this very unique method, and if you'll
just cross out the word "current," I
hope the sentence will make better
sense.
A
MARK
OF
QUAL Y
N
ON THE
FOLLOWING
E
PRODUCTS:
OM
Studio condenser
microphones and
accessories
Complete tape -to -disk
mastering systems
Cusrom studio mixing
consoles
N
N
For your local representative contact:
,1
AUDIO EXPORT
GEORG NEUMANN & CO.
71 HEILBRONN/ NECKAR FLEINERSTR. 29
POSTFACH 1180
Phone: 8 22 75
Telex: 728 558
Cable: AUDIOEXPORT HEILBRONN
J
Circle 24 on Reader Service Card
www.americanradiohistory.com
o-
o
t
A quest ion that has recurred
through the years appeared in my
mail again during the past month.
This particular reader asks, "Why are
good conventional hi-fi speakers unsuitable for musical instrument reproduction or public address work? What
are the major differences among
them ?"
ENVIRONMENTAL FACTORS
After having written that heading,
I find that it covers more than the
simple thought I had in mind when I
set it down. I was thinking of the
listening environment: what the place
in which you listen contributes to
what you hear. But it can also apply
to how the same environment influences the way the loudspeakers installed in it reproduce their sound.
So let us take those two influences
separately.
OWN LISTENER
We listen to sounds for much of the
time, and perhaps criticize them, without realizing that our surroundings
influence what we hear, quite considerably. If you doubt that, cast your
mind back to some time when you
may have been moving. After all the
furniture and perhaps the carpeting
had been removed from your living
room, did you notice what a hollow
sound the room seemed to have when
you spoke in it? Quite unlike the
room you had grown accustomed to
while you were living in it.
You may have been less conscious
that the family room, or the utility
room sounded quite different as an
environment, than your living room,
until you made that observation. As
you moved from room to room, the
sounds you heard in each seemed
quite normal for that room, so much
so that you were unaware that the
room contributed anything to those
sounds.
This is true, in a different way, of
EFFECT
auditoria. The natural reverberation
of an auditorium is something you
come to accept as natural for that
building, although it would seem
strange indeed, suddenly transplanted
into your living room. So one factor
in why systems have different requirements is the fact that you expect to hear different kinds of sound,
in different environments.
EFFECT ON LOUDSPEAKERS
In previous articles and columns,
NORMAN H.CROWHURST
we have pointed out
that different
kinds of loudspeaker systems suit different kinds of rooms. In the well furnished, more absorbent kind of
room, loudspeakers with a wide, flat
frequency response and uniform dispersion over the frequency range will
sound good, giving what would be
identified as high fidelity performance.
In the more reflective environment
of a family room, a different type of
loudspeaker system will sound good:
one that utilizes the many reflecting
surfaces to achieve the overall effect,
rather than one for which multiple
reflections would detract from the
performance.
Either system, listened to in the
environment that suits it, would
sound good, be recognized as a high
fidelity system. But now trade places.
In the wrong environment, each system would cease to give the same
impression of high fidelity. This
proves that loudspeakers sound different, according to the environment
you put them in.
PROGRAM FACTORS
Within limits, I suppose you can
listen to any kind of program in any
-a
kind of environment
pop concert
in a church, or a symphony orchestra
in a football stadium. This kind of
thought again links back to the environment. But considering kinds of
program also links to how you expect
each kind to sound. You would not
expect a full concert organ to sound
like a harpsichord (although it may
have a synthetic harpsichord as a feature). Nor would you expect a harpsichord to sound like a concert organ!
Accordingly, loudspeakers designed
to reproduce an electronic organ, or
an electronic harpsichord, will do
their job best if each complements
the instrument it is intended to reproduce. Similarly, a loudspeaker for
use with an electric bass needs plenty
of good, boomy bass and very little
in the treble range. But if your symphony orchestra came out sounding
like an electric bass, you would not
like it too well, would you?
As opposed to that situation, where
the loudspeaker will serve more effectively if its characteristics are similar to the instrument it is to reproduce, a high fidelity loudspeaker
should have no character of its own.
It should reproduce faithfully, whatever kind of sound is being fed to it
www.americanradiohistory.com
at the moment. This is a far more
rigorous requirement than will be expected of a unit that will be called
on to reproduce just one kind of instrument.
And what about public address
work? Doesn't that have to meet
similar demands to those made of a
high fidelity loudspeaker? In the
sense that, in some public address
installations, the loudspeaker has to
handle a wide variety of program
types, one might imagine so. But it
has to handle those varied programs
in a totally different environment
from that met by the high fidelity
loudspeaker.
The high fidelity loudspeaker operates in a relatively intimate environment-a living room, or a family room -and even those are different, as we have seen. In such an intimate environment, our hearing faculty is at its most critical. But the
public address loudspeaker has to
play its part in a much more public
environment.
Because of the sheer size of such
public places, the listening faculty of
the auditors is much less critical, although they may not be conscious of
the difference. We have met more
than one enthusiast for a public address installation who thought the
loudspeakers presented were the ultimate in fidelity, sounding better
than his hi -fi set, in his own living
room.
HEARING IS BELIEVING?
The old saying, "Seeing is believing," has been exploited through the
centuries by sleight -of-hand artists
who delude us with their magic acts.
Under those circumstances, we know
we are being fooled even if we don't
know how. We may be aware that
we can be fooled under other circumstances, but we are more reluctant to accept the fact that we may
have been.
The same is true of the faculty
that involves sound. Perhaps the
most convincing demonstration of
this that I remember concerns the
first really high power loudspeaker
unit I ever heard. I had been on vacation from the company that was
unit to handle 500
developing it
watts of sound, at an efficiency of
better than 50 percent. That means
it was capable of putting out more
than 250 acoustic watts.
Most "high efficiency" units, even
-a
today, seldom reach 20 percent efficiency. So that unit was really putting out a lot of power. I had left
for my vacation while it was being
built. When I returned, I thought
I heard a sound car making announcements in the next street from
my home. I wondered who it was,
so drove around to see. No sound
car. The sound must be coming
from the next street over.
No sound car there, either. I kept
going, toward the sound, until I
found it. The company was testing
the new unit, more than a mile from
my home. In those days, London
still had trolley cars, which made a
noise that had always drowned the
sound of loudspeakers.
I got right up to within a few feet
of the loudspeaker, and remember
being impressed with the fact that
it did not seem all that loud. It happened that I was standing listening to
it, on the opposite side of a sreet
where the trolleys ran. Presently a
trolley came by, and that was when
I could not believe my ears. I could
hardly hear the usual noise of the
trolley: it did not interrupt my hearing of the sound at all, even when
the trolley came betwen me and the
loudspeaker!
In those days, a 5 -watt speaker
was fairly loud, and it would be
fairly high efficiency at 5 percent,
which would mean it delivered 250
milliwatts of acoustical power. When
you think in watts, 250 watts is a
thousand times as much as 250 milli watts. But when you put that in dB,
it is only 30 dB higher in level. And
our hearing faculty can accommodate about a 120 dB range of levels.
That explained it. But the experience
proved it!
ROCK SOUND
So what makes modern rock groups
sem so loud? Of course, the fact that
they perform indoors, where reverberation builds up the energy, makes
the situation a little different from the
experience I just related, where sound
could go on expanding for miles. And
speaking of that, the fact that the
sound did not seem appreciably louder
as I moved from block to block
nearer to its source was due to the
fact that a block is only a fraction
of a mile. The level only raised a dB
or so for each block I got nearer.
But the bigger cause for difference
is the fact that rock people always
operate their system up where it runs
into distortion. It is the presence of
distortion that really makes it seem
loud, not the power they have.
This explains why these rock groups
keep demanding more power and
never seem satisfied. In their minds,
200 watts should be twice as loud as
100 watts. Then 500 watts should be
times as loud as 200 watts. And
1000 watts would be twice as loud as
500 watts. Actually, those steps in
loudness are only 3 dB, 4 dB and 3
dB, respectively. What gives the impression is not how many watts you
have, although more watts will make
it seem a little louder.
21/2
What really makes the rock groups
loud, is the fact that they run into
however many percent distortion
sometimes nearly 100 percent. As we
mature, we find distortion unpleasant.
It jangles our nerves, not much less
when a 10 watt amplifier is run into
high distortion, than when a 1000
-
watt amplifier is used. The latter is
just 20 dB loude r.
Try keying 20 dB of attenuation,
in and out. Th.e difference, admittedly, is quite noticeable. For that
matter, 10 dB is noticeable. But 2 or
3 dB requires careful listening, to
tell the difference. Isn't it time we
started giving our young people an
education in /physics that told them
some of these single facts of life, because if they would suffer their extra
"loudness" at. 10 or 20 dB lower, it
might get tb e resultant sound below
the threshold of hearing, a block or
so away, vvhere we might happen
to be!
A
MARK
OF
QUAL Y
ON THE
FOLLOWING
PRODUCTS:
"Mognetophon"M
professional
recorders
1/4
12
lape
"Magnetophon "M
FU
KE
15
master tape recorders
up to 24- tracks on 2"
width tape
N
Il
IIIF
Outside the U.S.A. and Canada contact:
AEG- TELEFUNKEN
Department "Magnetophon"
D -7750 Konstanz. West Germany
P.
0. Box 2154
Telex: 733233
Cables: telefunken konstanz
Phone: (07531) 852495
Circle 25 on Reader Service Card
im
ccizo
In the April issue, this column discussed the AAAS convention and the
concurrent exhibit which took place
at the Lincoln Center Library in New
York City. In that video exhibit, the
first cameras functioning without vidicons were on display. We briefly indi-
cated that miniaturization had come
to the camera as a result of a new development, the CCD or charge -coupled device. This made the solid -state
video camera truly solid- state, with
not even the vidicon to contend with.
Let's take a look a how these new
tubeless wonders work.
HISTORY OF TELEVISION
First, a peek at the chronology that
led up to this momentous new position in the video field. Back in 1873,
the light sensitivity of selenium was
discovered. Just two years later, the
first electronic television system was
demonstrated. It could only detect and
transmit the presence and absence of
light, but this was the first time moving images were transmitted electronically. The method used to detect
light was an array of 100 (10 x 10)
selenium photo -cells.
In 1880, a principle for scanning
was devised, and in 1884 the first
camera using the rotating disc principle for scanning was developed. The
method was to have a single spiral
around the center. As the disc revolved, each hole closer to the center scanned a line lower on the subject. For a scan of 60 lines, it was
necessary to have 60 holes. Equally
spaced holes delivered equally spaced
scan lines.
The next step came in 1897 when
the cold cathode ray tube with magnetic deflections and fluorescent screen
was demonstrated. Although a system
of television using the CRT for both
transmitter and receiver was first proposed in 1911, it wasn't until 1923
that the system was actually patented
usi-g the first electronic camera tube,
the iconoscope.
Then, in 1940, the recommendations
of the National Television Standards
Committee for a television standard
in this country was accepted by the
FCC, and the NTSC system we use
today came into existence. After that,
most equipment and systems were designed around this standard for compatibility.
The next two steps made possible
MARTIN DICKSTEIN
11 a
"Eye" on
a
Tubeless TV Camera.
the development of the closed circuit
television systems used in non- broadcast applications. In 1947, the first
transistor was developed and the solid
state of electronics was born, and just
three years later the vidicon came into
existence.
Next came the introduction of the
charge-coupled device in early 1970,
but it wasn't until this year that the
camera was introduced which made
use of an array in a general fashion
similar to the one demonstrated exactly 100 years ago this year! Generally, the CCD will find application in
fields making use of memory circuitry
and analog delay, but most rapidly in
the imaging area, the one with which
we are most interested here.
CHARGE -COUPLED DEVICE
A CCD, requiring technology similar to that for producing other silicon devices such as the mos, is a
wafer of a particular type of silicon
covered by an oxide layer. Metallic
electrodes are deposited on the layer.
By charging the electrodes positively,
electrons will collect at them selectively according to the intensity of the
positive charge. By transferring the
positive charge from electrode to
electrode, the packets of electrons can
be made to transfer accordingly. If an
electrode were charged negatively, this
would prevent the electrons from
moving in the wrong direction and
assure proper transfer. This, in essence, is the way the CCD functions.
In the case of the imaging device,
the charge is introduced according to
the light pattern of the subject picked
by the device. Different methods can
be used to collect the electron packets for conversion to impulses for
transmission of the images. In the
frame transfer method, for example,
the entire device consists of three vertical layers, with common horizontal
electrodes. During a frame period, the
light hits the first layer and electron
bundles are formed. During the vertical retrace time, the entire array is
pulsed and the electrons are transferred to the middle layer, in time for
another frame to begin forming.
The second layer stores the "image" and feeds it on in sequence and
at a specific time. During a horizontal
retrace blanking period, the bottom
line in `B" layer is fed to "C" layer
and then one element at a time horizontally to the video output diode and
amplifiers. These signals then modulate the beam in the display system
to recreate the image. It can be seen
that the more elements used in the
CCD, the higher the resolution of the
image. However, for practicality, there
are cerain limitations to the array arrangement. To provide broadcast
quality, it might be necessary to have
an array of somewhere near 500 x
500. If color were included, this would
require, at present, triple such arrangement. To achieve requirements
according to the NTSC RS-170 standard, RCA uses an array of 512 x 320
elements in the three -layer configuration.
This setup was arrived at by complying with the mathematical dictates
of the standard. Considering the need
for a 525 -line scan, the 2:1 interlace
requirement, the limitation of the usual closed circuit systems to 3 MHz in
the luminance bandwidth, and the aspect ratio of 4:3, the 512 x 320 configuration can be calculated. Extra
elements are included to account for
variations in system blanking and timing and to provide greater uniformity
around the edges of the picture.
RCA'S BIG SID
The CCD utilized by RCA is considered to be the biggest of its kind
presently in use. Since they named
their unit SID (Silicon Imaging Device), they actually call it Big SID.
With its over 1633,000 elements, the
resolution is higher than other similar units. In order to drive SID, a custom cmos has been developed which
provides all the proper voltages and
waveforms, takes the place of 35 conventional i.c.'s, and is already capable
of driving three Big SIDs when color
systems are introduced. (Incidentally,
SID, at just under 1.5 in. in length, is
100 times greater in area than the
conventional i.c., and has electrodes
so small that eight of them are equivalent to a human hair.) It is estimated
that the CCD applications will grow
$300 million a year in the next ten
years. SID will obviously be around
for a while.
RCA is offering two grades of SID.
For critical applications, a unit will
cost $2,300. Where budget is primary,
the cost will be $1,500 for the lower
grade device. The primary difference
"is with regard to the stringency of
blemish screening criteria." Delivery
of SID (and the two cameras being
offered which include this device) is
expected to be in the second quarter
of this year. It is anticipated that the
cost of devices similar to SID will
be available around 1980 for about
$30.
cent lighting and will operate satisfactorily in the 0.2 foot -candle range.
With fluorescent lighting, minimum
levels will run about two foot-candles.
(Incidentally, although the camera
plugs in to standard power, it operates on 15V and its consumption is
only 1.5 watts.)
ADVANTAGES
The advantages of the new technology in the video camera are that
the CCD avoids the lag that is common with the vidicon during the object movement, it does not bloom,
eliminates vidicon replacement due to
defects of breakage, face spots or
in. long.
It looks as if we have passed Buck
Rogers by a long shot. Now all we
have to do is to catch up to Dick
Tracy. Wristwatch t.v. camera- receivers may not be far off after all.
A
MARK
SOLID -STATE CAMERAS
The cameras (Models TC1150 and
TC1155) are black /white units and
can be purchased with either of the
SIDs. With the higher priced device,
the camera will cost $3,800, and with
the lower grade one it will be $3,000.
The TC1150 comes with a built -in
lens, adjustable from 14mm to 45mm,
with automatic light control, lv p -p
composite output (BNC connector),
weighs 2.5 lbs., and is less than 6 in.
long and less than 3 in. high. The
TC1155 comes with a standard "C"
mount to allow for choice of lens, and
has a greater sensitivity to permit operation in lower light levels.
Another camera using the solid state technology is Model Z7892 by
General Electric. It uses a charge-injection device (CID) sensor. It contains 244 rows of 188 elements each,
and is also capable of providing an
output compatible with standard t.v.
systems. The camera has a "C" mount
and comes with a 25mm, f-1.4 lens.
An optional lens system is available
which provides automatic light compensation.
The smallest camera of this type is
the Fairchild my -101. This unit is 3
in. in diameter and only /s in. long.
It weighs 11 oz. It uses a charge -coupled device with 10,000 photo -sensors. It has a "C" mount, comes with
a 25mm lens, and provides a 2V p -p
output. The vertical scan rate is 123
frames /sec. with 2:1 interlace, however, and since this does not conform
to standard t.v. receivers, a special
monitor is provided to accept the
camera's output signal.
It's interesting to note that since
burnout, is extremely low powered in
operation, and avoids the need for
critical alignment, necessary with vidicons in color applications.
As a final note on cameras, the
world's smallest camera was introduced last April. It is a vidicon -type,
using a tube only 0.5 in. in diameter
(made by British EMI). The camera
(produced by Reten Electronic of W.
Germany) is 0.75 in diameter and 5.5
ON THE
FOLLOWING
PRODUCTS:
,Ñ,
n
(E
M
OF
QUAL Y
reA
T)
1
the sensor used is responsive in the
infra -red region of the light spectrum,
it is suggested that the camera's performance is maximized in incandes-
TE LE
F UN
KEN
Sold and serviced exclusively
in the United States
1,4,
GOT
I---I
AM
AUDIO CORPORATION
Telefunken and Neumann are
also exclusively represented
by Gorham in Canada.
741 Washington
Street, New York, NY 10014
g
(Tel: 212-741-7411)
1710 N. La Brea Ave., Hollywood, CA 90046
(Tel: 213- 874 -4444)
Circle 26 on Reader Service Card
RADFORD
MARTIN DICKSTEIN
Audio Measuring Instruments
Laserium ...Light With Music
Low Distortion Oscillator
Series 3
A
A continuously variable frequency
laboratory oscillator with a range of
10Hz- 100kHz, having virtually zero
distortion over the audio frequency
band with a fast settling time.
SPECIFICATIONS:
Frequency range: 10Hz- 100kHz (4 bands)
Output voltage: 10 volts r.m.s. max.
Output source resistance: 150 ohms
unbalanced (plus 150/600 balanced/
floating)
Output attenuation: 0 -100dB (eight,
10dB steps plus 0 -20dB variable)
Output attenuation accuracy: 1%
Sine wave distortion; Less than 0.002%
10Hz -10kHz (typically below noise
of measuring instrument)
Square wave rise and fall time: 40/60
n.secs.
Monitor output meter: Scaled 0 -3, 0 -10
and dBV.
Mains input: 110V/13,0V, 220V/240V
Size: 17" (43cm) x 7" (18cm) high x
8%" (22cm) deep
Price: 150 ohms unbalanced output:
$950.00.
150/600 unbalanced /balanced floating
output: $1070.00.
Distortion Measuring Set
Series 3
A sensitive instrument with high input impedance for the measurement
of total harmonic distortion. Designed for speedy and accurate use.
Capable of measuring distortion
products down to 0.001 %. Direct
reading from calibrated meter scale.
SPECIFICATIONS:
Frequency range: 5Hz -50kHz (4 bands)
Distortion range (f.s.d.): 0.01% -100%
(9 ranges)
Input voltage measurement range:
50mv -60V (3 ranges)
Input resistance: 47Kohms on all ranges
High pass filter: 12dB /octave below
500Hz
Power requirement: 2 x PP9, included
Size: 17" (43cm) x 7" (18cm) high x
8 %" (22cm) deep
Price: $770.00
AUDIONICS
CO
10035 NE Sandy Blvd.
Portland, Oregon 97220
Authorized U.S. Sales Agency for
Radford Laboratory Instruments
fusion of music and the incredible colors produced
-a different entertainment experience.
by the laser
the entrance to
the Hayden Planetarium, there
is a crowd waiting to go in to see Laserium. Most of the visitors have already purchased their tickets from
Ticketron, but some will form a line
in hopes that this performance is not
a sell -out. Maybe there will be some
tickets still available at the box office.
A few minutes before the program
is to begin, the audience is allowed
to go upstairs and find seats in the
dimly lit circular amphitheater under
the planetarium dome. In the center,
stands the Zeiss star projector. There
is music, and there is a feeling of excitement and anticipation which always seems to be engendered in the
domed room, with its mysterious access to the universe.
A member of the Planetarium staff
welcomes the audience (right on time)
and explains briefly that the show
will take place on the dome overhead,
that the images will be produced by
a laser (which is completely safe,
should anyone wonder) operated by
a laserist who will create the program
completely live. Brian Bassett, the operator of the laser console is introduced, and the lights begin to dim.
The stars come out and the skyline
of New York can be seen around
the horizon.
As the music begins, the lights fade
out completely and the room is in
total darkness except for the stars
overhead. (The audience reacts vocally with surprise and pleasure at the
beauty of the scene.) The music
swells and the stars begin to move as
they normally do. The skyline has
disappeared and the tension builds.
AS
YOU APPROACH
Martin Dickstein is well known to
readers of db. Special thanks to Ron
Bassett, Brian Bassett, and Michael
Gershman of Laser Images, Inc.
Circle 27 on Reader Service Card
www.americanradiohistory.com
1. Composite photo showing a laser
pattern above the dome of the Griffith
Observatory in Los Angeles.
A cloud begins to appear, seemingly in space -not really on the
dome. It moves gently, changes form
and color, increases in size and follows the quiet serene music. The colors are bright, very bright, and again
the audience reacts with pleasure. As
the music flows, so do the clouds. The
music ends and the clouds vanish.
The stars, which have been a background to the entire selection, continue to move.
VARYING SELECTIONS
The next selection begins. The music builds in rising pitch. Wild images
follow the music -this portion of the
show is totally different from the first.
The selections follow in this manner
-some slow and gentle, some rock
music, some contemporary music.
Each is different from any of the
others, and the images on the dome
take form in movement and shape as
the laserist feels the music.
During the selections, the audience
reacts to the images and the rhythm.
There
is
laughter, applause, "oohs"
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Typical laser light patterns, stimulated by ,nusic.
input equipment
and "ahs," and a big round of applause at the conclusion of each portion of the show. A creative bond between the lasarist and the audience
grows; one senses this sharing in the
increased vigor of the performer. He
sets up the patterns and shapes with
the pushbuttons, controls size with
rotary knobs, and moves the images
around the roof with the joy -stick
control which permits slow glides or
quick leaps of any of the figures he
has built up. He knows each note of
the music, and the musical group
seems to follow each move he makes
(or is it the other way around ?).
The music begins with Fanfare for
the Common Man by Copeland, includes The Planets by Holst and The
Blue Danube by Strauss, as well as a
selection from Clockwork Orange,
then changes completely in texture
and rhythm and driving power with
Tank and Abaddon's Bolero by Emerson, Lake and Palmer and Space
Race by Preston. The Pines of Rome
completes the performance. The multicolored clouds, vibrating shapes, and
undulating patterns diminish as the
music ceases, soften, and end the
show quietly.
When the audience has finally left,
after asking all kinds of questions of
the laserist and the operator of the
star projector, the star projector is
again positioned to show the stars as
they appear in the New York sky on
the date of the presentation. The
laser system is again set up with mirrors and beam splitters in proper positions for the first musical selection.
The tape is recued. The power supply is checked, the console buttons
and controls are put in proper position. The laserist, really the star of the
show (besides the overhead display)
takes a break and collects his energies
for the next show.
LASERIUM -HOW DID IT
ALL BEGIN?
word coined a little over
Laser
10 years ago to describe a newly invented device
has since become a
household word.
word devised just a
Laserium
few years ago as a name for a new
application for the laser and a novel
soon to become
human experience
a household word!
The laser came into being in 1960
and got its name from the method by
-a
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-a
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RAULAND -BORG CORPORATION
3535 W. Addison St., Dept. N, Chicago, III. 60618
Circle 28 on Reader Service Card
V
We take the wait
out of erasing lots of tape
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GARNER INDUSTRIES
Circle 29 on Reader Service Card
which it gives off its light-Light Amplification by Stimulated Emission of
Radiation. A laser makes use of the
principal of physics that energy is
emitted when outer electrons of specific atoms move from one energy
level to another in the right direction.
Part of that energy is in the visible
frequency range, and light results. The
color of the light is determined by
the wavelength of the energy. By stimulating this emission of radiation,
amplifying it, and projecting the
beam, the laser has been made to do
what it does best, project an intense
light.
Lasers can be made with a solid,
liquid or gas medium in a tube with
highly reflective spherical mirrors at
both ends. Gas lasers emit continuous
light and have been found most satisfactory for work with three colors.
Once the energy is released by use of
either an electric charge or rf frequencies, the light particles are pulsed
to travel between the mirrors until
they are released through a tiny "window" at one end of the tube. Output
energy is about 1 percent of the total
in the tube.
The light from a laser is very
unique, and differs greatly from ordinary light. When the sun or any kind
of light bulb gives off light, it radiates equally in all directions and the
What
would
t
you Air.
expect
"'#
an IMA to do?
Perform SMPTE intermodulation analyses
quickly and easily, even in the millivolt range?
Measure amplifier noise?
Measure transistor noise?
Evaluate magnetic tape drop -out?
Test oscillator amplitude stability?
Measure tape recording distortion?
Evaluate phono stylus wear and tracking?
Test electromechanical transducers
for intermodulation?
0 crown
1718 W. MISHAWAKA ROAD
CO
The Crown IMA does
all of it. Internal inter-
modulation distortion
is less than 0.005 %.
Write us for more
complete information
and application notes.
inTErnarionai
ELKHART, INDIANA 46514
219-294-5571
Circle 30 on Reader Service Card
beams are non -coherent. The laser
emits a beam which is coherent, extremely narrow (a half -inch at the
tube spreads to a diameter of only
about 3 inches in a mile) and the frequency band is also extremely narrow
for the emitted rays, resulting in the
brightesi and sharpest colors ever
seen. Nevertheless, the power required
for a laser can be very small. These
factors make the laser a natural for a
Laserium presentation.
THE LASER IN ACTION
The laser has found application in
medicine and surgery (eye operations
without incision, for example), space
measurement (checking distance from
earth to moon to within inches from
reflectors left by the moon -walkers),
industry (checking for microscopic
defects in parts and machines) and
even-as a potential weapon, mentioned
often in science fiction. (It can burn
a hole, when concentrated, through
solid steel.)
Experimentation has been going on
in the creation of holograms and 3 -D
motion pictures. Extensive use was
made of the laser in the Pepsi Cola
Pavilion at Expo '70 in Osaka, Japan,
for environmental displays. But for
the first time in public entertainment,
in the Laserium display, the laser,
with music, makes possible the whole
show.
Laser Images, Inc. of Van Nuys,
California, was incorporated in early
1971 "primarily to engage in the use
of lasers for design and theatrical
purposes, including, but not limited
to the production of designs, photographs, films, light shows, and light
show devices." After several commissions to create films for motion pictures and television, experimentation
led to the most dramatic form of laser
imagery-Laserium. L.I.I. is still experimenting, considering offers for
new shows for various institutions and
It is with deep personal regret
that we report the death, on April
13, of Herman H. Scott, founder
and former president of H. H.
Scott, Inc. of Maynard, Mass. Mr.
Scott was the inventor of the dynamic noise suppressor, R-C oscillator, and selective circuits. He received the Distinguished Service
Award from President Kennedy's
Committee on the Employment of
the Physically Handicapped.
Mr. Scott was a development and
executive engineer with the General Radio Corporation from 1931
to 1946, president of the Technological Instrument Corporation in
1946 -7. He founded H. H. Scott.
Inc. in 1947 and retired in 1972.
further
installations of the Laserium presentation.
a rock group, and planning
LASERIUM
Lasèrium, emphasis on the second
syllable, is a word derived from
"laser," and "planetarium," the location where the shows take place. It
played its first show under the dome
of the Griffith Observatory in Los
Angeles and is still running there.
In New York, the show began its
performances in October, 1974 at the
American Museum of Natural History, Hayden Planetarium. Images, created in four colors-red, blue, green
and yellow are cast on the 81 -foot
dome by a I watt laser, in association
with music. Each performance has
the same music, but the visual aspects
of every show are totally different.
Each presentation is unique, a one and -only done live by a laserist, who
operates a console with illuminated
pushbuttons, rotary controls, and a
joy-stick. The rack next to him houses
the laser, its power supply, and the
water cooling system (35 degrees C
maximum) to keep the laser's ternperature at its normal level. The rack
also holds the 4 -track audio tape recorder which provides the music for
the show and some control cues.
(Total system, costs about $100,000.)
The laser itself is approximately 4
ft. long and 6 in. wide and weighs 50
lbs. (It costs approximately $10,000,
acording to Spectra-Physics of Mountain View, California, who made this
unit.) Although similar models are
made with argon or argon /krypton,
this one is made with krypton. The
beams of light, with special optics,
and front surface mirrors (with 50
coatings) can be projected onto the
ceiling in dots (only about 4 in. in
diameter) expanded to circles to almost the diameter of the dome, take
the shape of geometric figures, or become nebulous clouds which seemingly float in open space.
Shapes change, positions vary slowly
and smoothly or in bursts and jumps.
Sizes, also controlled to follow the
music, can change gently or very
rapidly. Every change is made manually by the laserist, with only a very
few exceptions which are controlled
by the tape cues.
The sound portion of the presentation comes from two of the four
tracks on the tape. Stereo music plays
through two Crown dual 300 -watt
amplifiers and is distributed by four
Altec A -7 speakers located behind
(actually above) the perforated dome.
There are also six surround speakers in the amphitheater for fuller
sound and special effects. (This equipment is part of the Planetarium's regular sound system.)
Laserium really must be seen and
heard to be believed. The programs
are presented on Friday, Saturday
and Sunday evenings. Since the first
showing less than two years ago, over
a quarter of a million people have
come and experienced the shows in
various cities. About 50,000 of them
have come to the display at the Hayden. There are also showings at the
Gates Planetarium in Denver, the
Morrison in San Francisco, the Reuben H. Fleet Space Theater in San
Diego (and the Griffith in Los Angeles, of course). There is now a traveling show (with a screen instead of
a dome) going to colleges across the
country. All installations seem to be
doing well and will continue indefi-
nitely.
Make Laserium a part of your enjoyment this summer-wherever you
are. Experience! Enjoy!
IT'S A SMALL WORLD!
SMALLER AUDIO TRANSFORMERS
Sizes: -3/8" x 1-15/16", 15/16" x 1.1/4 ",
1
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x
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(Send for complete catalog)
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Circle 31 on Reader Service Card
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www.americanradiohistory.com
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FREQUENCY SHIFTER
s-,
New sounds are created by model
735 frequency shifter through a change
in the harmonic structure of any natural or synthesized sound received at
the input. The device creates shifts by
as much as +5 kHz through zero to
-5 kHz (and simultaneously the inverse) through turning of a master
dial. Three pairs of output jacks provide the up and down shifted signals,
as well as a variable mixture of both.
The amount of frequency shift is voltage controllable in a linear as well as
exponential mode. In the exponential
mode, the device is compatible with
keyboard controllers of synthesizers.
In the quiescent state, a threshold- sensitive squelch circuit eliminates any carrier feedthrough. Frequency response
is 30 Hz to 16 kHz. Comes on a 19 in.
rack mount.
Mfr: Bode Sound Co.
Price: $995.00.
Circle 50 on Reader Service Card
TWO -TRACK MASTERING
RECORDER
trol. Cue control allows cueing in
either the fast wind or pause modes
and for manual reel rotation during
editing. There is an automatic stop
function from the rewind mode and
a zero vu click stop on the output
level control. Adaptors automatically
compensate for the height difference
between 7-inch and 101/4 -inch reels.
Mfr: TEAC
Price: $999.50
Circle 51 on Reader Service Card
microphone with built -in variable echo;
footswitch operation of microphone.
Clearly visible vu meters enable the
operator to keep track of proceedings.
Mir: Audio Transport Systems
Circle 53 on Reader Service Card
PORTABLE PARABOLIC
REFLECTOR
BACKGROUND MUSIC SYSTEM
Background music system TRAK -4,
utilizing two playback decks, can provide music that will intersperse with
commercial announcements, or play
two musical formats. This is done by
interfacing two TRAK -4 playback
units and a mixer switch. The system
is also capable of playing 32 hours of
music before repeating. The unit is a
continuous-duty type of machine with
built -in amplification, microphone input, volume and tone controls. The
16 -hour tape magazine can be quickly
loaded or unloaded without threading.
The mixer switch may be set to play
the two decks alternately or in a 3:1
sequence.
Mfr: Tape -Athon Corp.
Circle 52 on Reader Service Card
Depending on climatic conditions
and surroundings, PBR -400 parabolic
reflector can pick up high quality
sound from a distance of up to several hundred yards. The manufacturer
claims that the PBR -400 will improve
the sound sensitivity of most omnidirectional microphones 10 to 20 dB
over rated sensitivity. Angle of acceptance is approximately 26 degrees.
The unit, weighing less than three
pounds, is hand operable or can be
used on a tripod. Included with the
reflector are a microphone stand adaptor, tripod stand adaptor, and carrying case.
Mfr: Superscope (Sony)
Price: $79.95.
Circle 54 on Reader Service Card
CUE CLOCK
DISCOTHEQUE CONSOLE
o
A switchable playback head and
101/4-inch reel adaptors are featured
in model A -6100, a 1/4 -track recorder
with four heads, one of which is a
1/4 -track playback head that is switch able on the head bridge. The three
motors are powered with a hysteresis
synchronous capstan drive. The dual-
N
functioning metering system, consisting of two vu meters to indicate average levels and two peak reading
led's to indicate transients allows the
user to record 3 dB hotter when using
high- energy tape. There is also a pad
for 15 dB or 30 dB of attenuation.
High- density heads have a flip -up
hinged head cover. The unit has two position bias and eq. switches, and
microswitch pushbutton transport con-
Compact package system ATS DC202, designed for the confines of discotheque use, offers the following:
stereo operation; auxiliary stereo input; complete cueing system with volume presents; program send to cue
buss; separate hi and low EQ. on program and mic channels; built -in 30
watt cue amplifier with speakers and
headphone output; gooseneck d.j.
www.americanradiohistory.com
"Cue Clock" is an up /down digital
timer which counts up to or down
from any thumbwheel preset time; a
cue light shows the end of count. A
"set" light indicates that the unit is
programmed and ready. The clock,
which operates manually or through
remote control, has a timing capacity
up to 99 min. 59 sec. It uses TTL
logic throughout, with a seven -segment
display. The clock starts automatically
when any switched voltage is applied,
without relays. Data outputs are provided for custom interfacing with
automation systems.
Mfr: Electroneering, Inc.
Circle 55 on Reader Service Card
THE PEAVEY 1200 MIXER
J
12 O O
In
STEREO
response to the market demand, we present the 1200 Mixer,
the first truly professional mixer for less than $1,000.
transformer balanced, low impedance mike inputs
12 unbalanced, high impedance line inputs
Input attenuation & mike /line selection
High and low equalization on each channel
Stereo pan on each channel
Three send controls on each channel, all having pre or post capability
Output slide attenuators on each channel
control
area consisting of left & right main slide attenuators
Master
with associated low, middle & high equalization and monitor slide attenuator.
Effects master, return & pan controls
Reverb master, return, & pan controls
600 Ohm transformer balanced outputs on left & right main and monitor
Lighted VU meter on left & right mains, externally adjustable.
12
Suggested Retail price
$949.50
FOR MORE ABOUT THE 1200 MIXER WRITE: PEAVEY ELECTRONICS, BOX 2898, MERIDIAN, MS. 39301
Circle 33 on Reader Service Card
www.americanradiohistory.com
new products & services (cont.)
AT LAST!
HIGH VOLTAGE PROBE
INSTANT FLANGER
FOR TV
LIMITER
CR
1
OUT
4
. 3os
CN
IN
°LOT
.3o. .°9
CN
DUT
3o.
RENI
.
Self- contained, direct reading, high
voltage and current measuring probe
model HVP -5 provides for the safe
measurements of voltage up to 40,000
volts d.c., and for separate current
measurements up to 200 mA d.c. It
measures accurately the high anode
voltage of a color picture tube and,
through the use of a switch monitor,
the cathode current drawn by the horizontal output tube or the output
stage. The two circuits are completely
separate, enabling the technician to
switch from the mA position to the
HV position without disrupting the
operation of the set under test.
Mfr: EICO Electronic Instrument Co.
Price: $29.95.
Circle 56 on Reader Service Card
SERVO FEEDBACK SPEAKER
SYSTEM
An effect modifier block on Instant FlangerTM model FL201 allows
"bounce" circuit to simulate true tape
flanging by imitating motor or servo
hunting. Depth control regulates the
percentage of direct vs. delayed signal, and relative phase. Other features include internal regulated power
supply, remote control capability, dual
outputs for pseudo-stereo, internal envelope follower, line in /out control
and indicator, high level input and
output, optional balanced line in /out,
full frequency response to 15 kHz,
automatic operation with oscillator,
mode indicating lamps. The control
configuration-oscillator, manual, remote- envelope may be used in any
combination. The Instant Flanger uses
a true time delay circuit, which the
manufacturer claims will produce
many more nulls and thus a deeper
effect than previously available with
an all- electronic unit. Construction is
all solid- state, with I.e.d. front panel
indicators. Internal circuit boards plug
in.
Mfr: Eventide Clockworks
Circle 58 on Reader Service Card
PRECISION SOUND -LEVEL METER
P.M iN
L
100T
4- channel limiters
for TASCAM consoles
(compatible in
price and design)
manufactured by
SOlv1 Q4¢v esi5
445 Byrant Street
San Francisco, CA 94107
Telephone 415/391 -8776
a TASCAM dealer
N
N
The servo system controlling the
SmartSpeaker line utilizes a sensing
network that compares the mechanical
analog of the speaker output with the
applied electrical inputs and then generates a correcting voltage. This voltage is fed back to the amplifier to
adjust the input to the speaker's voice
coil and thereby compensate for errors normally introduced by conventional loudspeakers. Other benefits
claimed include improved transient
response, reduced phase distortion,
and increased dynamic range. The
line consists of three models, model
15, a floor-standing three -way system,
model 12, a large bookshelf unit, and
smaller bookshelf system model 10.
Mfr: C/M Audio Components
Circle 57 on Reader Service Card
Circle 34 on Reader Service Card
www.americanradiohistory.com
The capability to "hold and display" the maximum level measured
on a digital display while an analog
meter continues to indicate lower
levels is a feature of the model 1981
sound -level meter. The meter features
both a digital display and a large,
linear analog meter, meets ANSI S 1 A
and IEC 179 specifications, and has
a measurement range of 70 to 120
dBA. The analog scale spans the entire 70 to 120 dBA range linearly in
1dB increments. While measuring,
either fast or slow detector response
may be selected. The unit is available alone or in sets or systems.
Mfr: General Radio
Circle 59 on Reader Service Card
offer for
a special
A
o
readers!
MUST
FOR
ANYONE
INTERESTED
IN THE
MUSIC
INDUSTRY-
Lewitt The 8uéutue -
o Owe, l3uMn&u!
Compiled from Recording Institute of America's interviews with key executives and
makers", plus Reference Directory and Dialogue's Viewpoints of industry "stars ".
"hit
-
...
including
RIA Reference Directory,
songwriter affiliation forms, sample
artist contracts, writer contracts, etc., in
addition to a Directory of Record Manufacturers, Music Publishers, Personal Managers,
Producers and Booking Agents. Also Record
World's "Dialogues" with over 50 candid
interviews from Record World magazine, and
a cross -section of "star" personality interviews.
Listen to the industry "pros" describe the
workings of the Music Business. Hear the
most respected attorneys of the entertainment field define and discuss the legal
terminology of Recording Contracts, Songwriter Contracts, Professional Management
Contracts. Over 31/2 hours of professional
reference
could be the most important
200 minutes of your life!
Plus
sample
...
You get all the above (regularly $49.95) for only $39.95 for db readers.
T
'Interviews include:
Pete Bennett
Promotion. Apple Records
Sid Bernstein
Personal Manager and Promoter
Rick Blackburn
Dir of Sales. Columbia Records
Terry Cashman
Bob Cato
Pres Cashwest Productions. Inc
V.P.. Creative Services. United Artists
Kip Cohen
V P
Al Coury
V P
Al De Manno
V P
Torn Draper
Dir
.
.
Producer. Phtla Int Rec Co
Pres
d.
V
Marketing, Atlantic Records
Barbara Haras
Dir
Emil Lavinia
Prof
Michael Martineau
Booking Agent. Premier Talent
Mark Meyerson
A&R, Atlantic Records
Barry Oslander
West Coast Prof Do
Richard
Law Firm of Roemer & Nadler
H
Roemer
V P
[
I
copies of " MUSIC INDUSTRY
CASSETTE LIBRARY
at S39.95 each.
Music Department. CMA
RBB. RCA Records
David Glew
Alvin Teller
TODAY
Production. Capitol Records
Kenny Gamble
P
- MAIL
Sagamore Publishing Co., Inc.
1120 Old Country Road, Plainview, N.Y. 11803
Please send
ABR A&M Records
.
ORDER FORM
Artist Relations. Atlantic Records
Mgt Chappell Publishers
.
JObete Music Co
Please
Print
Name
Address
Zip
State
City
Merchandising Marketing
Columbia Records
Peter Thall
Law Firm of Casper & Tnau.
Ron Wersner
V P
P
C
Artist Relations Buddan Records
...
and many others
Total Amount
S
Check /Money Order for
10 Day Money Back Guarantee
www.americanradiohistory.com
S
db,
new products & services (cont.)
FRICTIONLESS TURNTABLE
fixed or scientific notation; and per-
form conventional arithmetical functions with the contents of its single
addressable memory. Since several
keys serve multi -functions, the number of operations possible has been
compressed into a small size. The device, which operates on two rechargeable batteries, features an RPN logic
system with a four -memory stack that
holds intermediate answers and auto-
CARTRIDGE TAPE SPLICE
FINDER
240 volt /50 Hz automatic cartridge
tape splice finder and bulk eraser,
model SFE -3, has been developed to
cut broadcast cartridge handling time
by automatically locating a splice on
a cartridge and kicking out the cartridge with the tape stopped just beyond the splice point, without the
need for human surveillance. Recording begins immediately after the
splice, precluding the possibility of an
audible blip. The pressure-sensitvie
device does not require a prerecorded
signal. It will also detect tape fractures
and exercise the tapes for better performance. An optional built-in bulk
eraser allows cartridges to be erased
and searched on the same machine.
Mfr: UMC Electronics Co.
Circle 60 on Reader Service Card
Model 8004 turntable features gyro poises frictionless magnetic suspension of the platter and single point
tone arm suspension. Powered by a
24-pole synchronous high torque motor, it has belt drive. The tone arm
has a magnetic hold bar and antiskate control adaptable to all types of
styli. The turntable is equipped with
a state-of- the -art cartridge, either the
681 triple -E calibrated to the tone arm
for stereo playback or 780 /4DQ for
discrete.
matically brings them
needed in calculation.
Mfr: Hewlett-Packard
back
Price: $125.00.
Circle 62 on Reader Service Card
FUNCTION GENERATOR
Mfr: Stanton Magnetics
Price: Stereo: $199.95
4- channel: $224.95.
Circle 61 on Reader Service Card
ENGINEERING CALCULATOR
CHEAP
hut not dirty
Trigonometric and logarithmic functions are handled by 6 -ounce HP-21
scientific calculator. In addition, the
user can calculate in either degrees or
radians; convert from polar to rectangular coordinates and vice versa;
format and round the display in either
Available in either kit or assembled
form, model 1271 function generator
generates sine, square or triangle
waveforms from 0.1 Hz to 1 mHz. A
short- circuit -proof output amplifier
supplies a 10 -volt peak-to -peak signal
into a 50 -ohm load. A calibrated step
attenuator adjusts from zero to 50dB
(10V p-p /30mV p -p) in 10 dB steps.
20 dB additional attentuation for each
step for a total of 70 dB is achieved
through the variable attenuator control. The manufacturer claims attenuator accuracy is
1 dB.
-
Mfr: Heath Company
Price: Kit: $99.95
Assembled: $140.00.
Circle 63 on Reader Service Card
R9
50 Watts -4.0 or 8.0 Ohms minimum sine
wave continuous average power from 20 Hz
to 20 kHz with less than .05% total harmonic
C6
distortion.
Our power amplifiers are some of the best
available. Our prices are some of the most
reasonable available. You may not be familiar with our products since we sell only by
direct mail and don't advertise a great deal.
We would like to send you our new 1975
catalog showing all of our fine audio products and test report information on our
famous "Tiger .01" shown above. You
might be pleasantly surprised at how little
clean power actually costs.
v
N
#207 Complete Kit
$ 77.50 PPd
=207 -A Assembled Amplifier
$110.00
PPd
Southwest Technical Products
Rhapsody
San Antonio, Texas 78216
-74l ÍiJ 219 W.
when
RI
R2
68K
470K
C3
470.f
R3
120K
IV
C2
5 µf
10V
27
IOOp
R4
470n
R5
N
*
GAIN ADJUST
MAX 10K
MIN
OA
CORRECTION
In the above direct -box diagram (which appeared in
db, April 1975, p. 18) the circuitry at two points,
A and B, was incomplete. The circuitry shown here
is correct.
Circle 35 on Reader Service Card
www.americanradiohistory.com
V DC
INS'IALL IT
AND FORGET IT!
WE BUILD AND TEST EACH AMPLIFIER WITH THE
CONVICTION THAT WE'LL NEVER SEE IT AGAIN
That's why 250/o of our people work in inspection and verification. And we have this confidence in our amplifiers because our people make sure you receive a better amplifier than you ordered. You'll find the Crown
line of power amplifiers unique in both specifications and operation. And that kind of confidence you can pass
on to your clients.
Output Power: 30 watts per
channel minimum RMS (both channels operating) into an 8 ohm load
over a bandwidth of 35 Hz -15
KHz at a rated RMS sum total harmonic distortion of 0.05%.
Dimensions: 19" wide by 83/4"
deep by 13/4" high.
Weight: 10 lbs.
The Crown D -60 stereo amplifier, small in size, big in
value and adaptability. Its uses include headphone power
supply for system monitoring; ideal power for high -efficiency speakers: can be easily used in bi- amping and tri amping situations and can be field modified to produce 25
volt monaural output power for industrial sound distribu-
tion systems.
The D -150 medium power amplifier, is by design an
ideal audio amplifier with the kind of rugged reliability
needed in portable sound systems. Especially where one
to one amp /speaker ratios are used. Well known Crown
protection circuits are an integral part of the D -150.
Output Power: 75 watts per channel minimum RMS (both channels
operating) into an 8 ohm load over
a bandwidth of 1 Hz -20 KHz at a
rated RMS sum total harmonic
distortion of 0.05%.
Dimensions. 17" wide by 83/4"
Protection from mismatched or shorted loads is provided, and a series limiting resistor protects against excessive input signals. Controlled slewing -rate voltage
amplifiers protect against RF burnouts. And a thermal
switch cuts AC line power if overheating occurs from improper ventilation.
deep by 51/4" high.
Weight: 24 lbs.
The Crown DC -300A. High power is first thought of
when referring to a "super" amplifier. However, this
Crbwn amplifier is also super in its reliability; super in its
capability to deliver sound without distortion, and super
in its ability to power any type of load. from 2.5 to 16
ohms. resistive or reactive! And whether it powers a
multi- speaker theatre system or is on line with a group of
twenty or thirty DC-300A's for an outdoor rock session,
this amplifier delivers 100%. And we know that in whatever application you use it, the DC -300A will give you the
kind of reliability you're loolçmg for.
Output Power: 155 watts per
channel minimum RMS (both channels operating) into an 8 ohm load
over a bandwidth of 1 Hz -20 KHz
at a rated RMS sum total harmonic distortion of 0.05%.
Dimensions: 19" wide by 93/4"
deep by 7" high.
Weight: 45 lbs.
The Crown M -600 power amplifier was designed specifically for applications requiring relatively high power
levels. The M -600 maintains all the exacting Crown laboratory performance standards, plus featuring built -in
cooling for continuous full power operation.
The M -600 also features Crown's patented protection circuitry allowing it to drive highly reactive and
low impedance loads without adverse effects. A newly
patented output bridge circuit permits extremely high
power levels to be sustained safely.
Output Power. 600 watts minimum
RMS into an 8 ohms load over a
bandwidth of 1 Hz -20 KHz at a
rated RMS sum total harmonic
distortion of 0.05%.
Dimensions: 19" wide by 16'b"
deep by 83/4" high.
Weight: 92 lbs.
If by this time you do not have
enough power to do the lob, consider the M -2000. DC -1200 or the
DC -4000.
These configurations
are combinations of the M -600
and are specifically designed for
applications where huge amounts
of power (2 kilowatts plus) are
needed.
Crown amps are widely known
for superior performance and reliability, and like every Crown product are covered by a comprehensive warranty which includes
parts, labor and round -trip ship ping for three years.
a
L
crownQ
7
m
BOX
1000 ELKHART, IN. 46514 219 /294-5571
Circle 40 on Reader Service Card
www.americanradiohistory.com
V
"'
Jim Nielsen at the console at Freeway Recording.
Wally Heider's Studio C, just completed, set for a
John Coaltrane album.
STEPHEN H. LAMPEN
How Audio Is Doing
In San Francisco
Major recording studios seem to be holding their own,
with many garage -types doing a lot of budget work.
Manufacturers feel the pinch of tight money.
TIMES have hit all sections of the audio industry. But, in the San Francisco area at least,
the response to a tightening money situation
and a drop in customers has been most unorthodox: Build now!
Among the ten 16- or 24-track recording studios surveyed, seven were in the process of expanding or improving their facilities. "It was a question of expanding while
we still had the money and fewer customers to bother, or
waiting until it was too late," I was told. Still, all admitted
that the hecic, profitable days of the late sixties when the
Grateful Dead, the Jefferson Airplane and Santana dominated the rock industry are gone now and may never return. At that time, some studios were booked a year or
more in advance. Now, a week's notice
less in some
cases
all that's necessary. And, while two large studios
have folded in the last couple of years, neither termination
was due to the present financial conditions. Perhaps curHARD
-is
-or
Stephen H. Lampen is the owner of 3P Recording in
Ñ
San Francisco.
rent circumstances now can be best described as solidification.
TIGHT MONEY EVERYWHERE
The same cannot be said of the manufacturers, however,
to whom tight money means strangulation. Almost all
manufacturers who were around five years ago are still
here, but the picture still looks grim for some. I was told
of one major manufacturer's chief executive appearing
before the stockholders in makeup, to indicate subconsciously that the company was as healthy as his ruddy
appearance. Don't know if it worked!
Distributors and representatives are a quick- moving,
fast -talking breed, almost impossible to keep track of over
the years. Over thirty pro dealers cover the Bay Area with
practically every line of recording, broadcasting, duplication, and public-address equipment. Some are borderline pro, offering what could easily be called good hi -fi equipment but also selling to small studios and independent producers who cannot afford major studio prices.
Thereby hangs another change in the sound scene: the
tremendous rise in the number of studios -in- garages. Any
estimates as to their number would be difficult because
www.americanradiohistory.com
Record Plant's psychedelic Studio B.
The cutting room at Fantasy Records.
many do not advertise for customers. But there must certainly be over a hundred of them cranking out marginally
acceptable quality programs for budget labels or broadcast.
FREEWAY RECORDING
Minorities and women were not very much in evidence
in any of the studios visited, the one exception being Freeway Recording in Oakland, which is owned by Bernie
Reveira. Because of his minority status, he received a substantial SBA loan to start his studio and other ventures.
From what we saw, the money was spent intelligently. A
custom Opamp board feeds their 3M 16 -track machine
which can be mixed to two 3M 2- trackers. A dbx 216
noise -reduction system is used.
Other support equipment includes UREI 527A graphic
equalizers and 1176 limiters, Spectrasonics 610 complimiters, McIntosh and Crown power amps. Besides the
Altec 604E's which almost every studio offers, Freeway
had a double -pair of Quad electrostatics. While clean, and
even with the surprising low -end which a pair produces,
they lack the power-handling abilities of standard speaker
designs such as the Altecs. When we visited, they were just
completing the installation of the studio and were looking
forward to major business in the near future.
WALLY HEIDER'S
Wally Heider's, in San Francisco, is a different story.
Although not the oldest studio in the city, they are one
of the first which come to mind because of their work
with the rock stars of the last ten years, turning out one
Sierra Sound's recorders.
million-seller after another. Studio C, upstairs, had just
been completed and, even with plaster still on the floor,
was set up for Van Coaltrane, who was doing some work
later in the day. Hot Tuna was also in the building in
Studio D. All studios, in fact, most of the Heider chain,
standardize their equipment: Dimidio custom board, modified by Miter Productions; 3M 24- or 16 -track recorder;
3M 2 -track machines; Altec 604E monitors; McIntosh
275 amps; UREI LA3A and 1176 limiters; Dolby 361As
in one room; APL 550 EQs on all board inputs in Studio
C; Pultec PEQ -2 equalizers. Studio A had a Quad -8 board
modified to 24- channel use and also had the Altec 891A
mini monitors for limited range mixes.
RECORD PLANT
Meanwhile, Record Plant in Sausalito, the "beautiful"
studio in the Bay Area, is also expanding its facility. In
keeping with its "subdued freak" decor, the new studio,
dubbed The Pit, will be recording -in- the -round-with a
twist!
"Where's the console going to go ?" I asked the secretary.
"Why, right here," she said pointing to a large opening
in the circle of what will be plush seating.
"What about recorders ?" I continued.
"Over here," she indicated, pointing to smaller gaps in
the seating.
"Well then," I asked, "where's the studio if this is the
control room ?"
"This is the studio," she insisted.
Everything's portable at His Master's Wheels, even the
Neve console.
www.americanradiohistory.com
N
Engineer & producer working on commercial at
Different Fur.
Columbia's cutting room. Their patchbay is the largest
the author has seen.
At this point I gave up. But I can't wait until it's finished and I get to see what they did. These two existing
studios, often the hangout of Sly and the Family Stone,
are plush-plush-plush designed with the richer labels in
mind by Westlake Audio. API boards feed 3M 24-track
and 2 -track machines, with extra Ampex 2- tracks, and 4tracks. Dolby M -16 or M -16 -8X units provide noise reduction with UREI LA3A and 1176 limiters, Eventide phasers,
Pultec equalizers, Cooper Time Cube, United Audio's Little Dipper and Westlake monitors filling out the scene.
I strolled among the studios. "And this," continued my
guide, pointing to a deep fold in the tapestry wall, "is
where Sly puts his baby when he's recording." I look
puzzled. She continued. "They put a mic on the kid and,
every so often, the engineer hits the solo button to see if
the little one is crying." A customer breakthrough: nursery
service!
In the other direction, down the peninsula, we find Pacific Recording finishing up Studio 2. The main studio is
supplied with an Ampex MM- 1000 -16, 2 Ampex MR-702, and 440 -1, all fed from a custom board. The Grateful
Dead cut their first hits here.
been re -fitted for film scoring, complete with Magnatech
mag -film machines and complete projection equipment.
The film version of "One Flew over the Cuckoo's Nest"
was waiting to move in.
SIERRA SOUND
Across the bay in Berkeley, Sierra Sound is working hard
with mixing TV tracks for the Serendipity Singers, many
gospel groups and some commercials. Sierra will be reworked completely this year, owner-chief engineer Bob
de Sousa told me. "We can't stay in business without doing it. Customers require absolute separation." Quite a
tall order, I would think, and if he succeeds, I want to
know who the architect was.
co
N
FANTASY RECORDS
Only a few minutes away from Sierra lies the massive
concrete blockhouse of Fantasy Records. I was amazed to
see a customer actually turned away! I asked why, and
manager Jim Stern's reply was, "We do only in -house
production; we don't need any outside business."
With three well- equipped studios-Studio A had just
been completed -they must have a solid core of return
customers. He assured me they did. Still, in spite of their
entry hall lined with all the Gold Records earned by
Creedence Clearwater Revival, times have calmed down
for them as well. This is the only concern in the Bay Area
that does recording, cutting, record promotion, and distribution under one roof. All they're missing is a pressing
plant of their own, something Mr. Stern said they were not
planning on establishing. Farming out the work worked
fine. Studio A, one of the largest rooms in the area, had
HIS MASTER'S WHEELS
One of the newest studios in the area is San Francisco's
His Master's Wheels which, as the name suggests, does a
lot of on- location recording. However, they also maintain
a studio equipped with their totally removable gear. Everything is either carryable or on wheels. Part of a wall collapses to let their Neve console and two MM- 1000 -16
Ampex machines roll out and into the truck. They had
just finished recording the Grateful Dead's last concerts,
which I had photographed, by coincidence, and they were
enmeshed in the re-mixing for record release and for the
feature film which had been shot.
The studio, the best acoustically I found in my survey,
has a skylight -but no outside leakage. Still can't figure
out how they did it. Their equipment also features Studer
A -80 -2 and Ampex 351 -2 machines, the latter modified
with MCI electronics, Phase Linear amps feeding JBL
or Klipsch monitors, Pultec equalizers, Eventide phaser,
Multi -Track equalizers and UREI graphic equalizers.
DIFFERENT FUR
Not far away lay Different Fur, a small, but prospering
studio, also in San Francisco. Pat Gleason told me they
had just had their 12th consecutive quarter of growth.
With their custom-built Spectrasonics console, Scully 10016- and 4- track, they could offer pro quality at a competitive price. But, the outlook was not that good, Mr. Gleason emphasized. "There's less business coming in the near
future for all studios, but we're not going in for price cutting. Any studio would be crazy to cost cut now. It's better to compete on service. There's no sense to lose money
working full- time."
COLUMBIA -COAST
The San Francisco scene is rounded out with the two
oldest studios in the area: the Coast -Columbia complex
and Golden State Recorders. Coast and Columbia both
seem to represent the conservative aspects of the industry;
they don't have the latest gadges-just the best. No doubt
part of the reason for this is that as part of the Columbia
chain, all equipment changes must be authorized through
the head office. Even I had to be cleared through the head
office! Still, being under a mother's wing has its advantages in hard times.
All artists on the Columbia and related labels use the
www.americanradiohistory.com
studio so that one has, in effect, a built -in clientele. Equipment available includes two Ampex MM- 1000-16- with
an EECO synchronizer for 30 -track recording if required,
4 digital delays, UREI LA3A limiters, and the largest
patch bay I have ever seen. "We can patch anything to
anything," Chief Engineer George Horn told me. There
are also Pultec equalizers, RCA limiters, Ampex 440 -4
and 440 -2 machines and monitoring on Altec 9845 speakers modified with J.B.L. 2420 drivers. A custom 38 -in
console feeds the system with rotary switching which can
bring any track from any machine up on any fader. Versatility, right?
The next room, Studio B, was busy with the mix for
Michael Schreve's new album, (Schreve is late of Santana.) Across the hall, Coast Recorders, a smaller studio,
held the last vestige from the umbrella days of a few
years ago: a large beach parasol over the drum set. They
had a 3M 8 -track and Ampex 300 -4, 440 -2, 300 -1 machines. Down the hall, the Columbia master room held
their Scully lathe with Westrex 3D -2 cutter and 440 Ampex playback machine.
GOLDEN STATE
And then we have Golden State, where hits they produced in the early fifties are still on the walls. This is also
the home of the College for Recording Arts, the only recording school in the area. Both are ably run by Leo
deGar Kulka, who, at first glance, looks sure to throw you
out for the slightest infringement, but who turns out to be
one of the nicest people I met on my journeys. With their
Stephens I6- track, custom board and an ancient (but rock solid) Ampex 200 full -track complement, as well as Altec
604C monitors and support gear, they offer not only a
well- equipped atmosphere but a good place to learn.
So, everyone seems to be surviving. In some cases, one
might almost say, prospering. I still think of one of the
defunct studios. I heard through the grapevine that the
owner had to choose between his wife and the studio. Maybe he made the wrong choice.
Mike Stobin Co. 836 -2937
MENLO PARK:
H
&K Sales. 369-6244
Sony
Hervic
Winlab
Marantz
Grace
Supex
OAKLAND:
General
Electronics Systems, Inc.
658-9490
Neumann
Electro -Voice
Sennheiser
Turner
Shure
AKG
BASF
3M Tape
Switchcraft
Rauland
Sony
Atlas
Argus
Ampex
Teac
Tascam
REDWOOD
AKG
Ampex
Vega
Norleen Sound Service. 652 -2631
3M Tape
Audiotek
Editall
Electro -Voice
Atlas
Hank Gabriel. 465.5361
Fairchild
DBX
Sescom
Telex /Magnecord
University
Edcor
Mohawk
Sony
Parasound
Shure
Tascam
Switchcraft
Marantz
Nortronics
Spectrasonics
MRL
Teac
Electro -Voice
True Recordings. 652 -8863
Revox
LPB
AKG
Altec
Cetec
Crown
Scully
Crown
Tandberg
Nagra
Otari
McIntosh
Beyer
Co. 562-9241
Editall
Neumann
Telex
Recortec
Taber
Royal
Liberty
Magnetic Tape Distributors
Accuphase
326 -3540
3M Tape
DALY CITY:
465.1312
The Woodworth Company
Cetec
365-0252
Waters
Gauss
CMS
Electro -Voice
Cetec
Shure
Gauss
Turner
Audio Tape
Audio Pak carts
LAFAYETTE:
Wilkins -Mason Associates
284 -9200
Ampex Tape
Phase Linear
Koss
Audio Tape
Electro -Sound
JVC
Cass Electronics. 834-4225
DBX
Research
Countryman
Russco
Stevenson
Tascam
Sennheiser
VIF
Soundcraftsman
Acoustic
Innovonics
3M
Revox
UREI
Audio Technica
QRI Corp.
Asco
1BL
Professional Audio Electronics
654.6630
Electro -Sound
Electro -Voice
Paul Seaman
Teac
Tascam
TDK
CITY:
Accurate Sound. 365-2843
DBX
All Area Code 415
Sennheiser
Tandberg
Beyer
Fairchild
Soundcraftsman
DISTRIBUTORS /REPRESENTATIVES:
Revox
Vega
Sony
Shure
Lamb
Teac
Uher
Klipsch
our computer!
Western Audio Imports. 321 -0664
Crown
McIntosh
AKG
R-Columbia
Memorex
Sony
Crown
Accuphase
Thorens
As an aid to those working In the Bay Area we list
herewith a directory of DISTRIBUTORS and
REPRESENTATIVES that handle professional equipment. Also listed are MANUFACTURERS of pro -audio
equipment. We have made every attempt to make this
little directory as complete as possible, but since
that seems to be an impossible feat, we will bring it
up to date as soon as we receive the usual indignant
"you- left -me -out" letters. Maybe we can blame it on
PALO ALTO:
MB
Phillips
Altec
Shure
BAY AREA DIRECTORY
SAE
ADS -Braun
SAN CARLOS:
Dobbs -Stanford. 592.5958
Crown
Switchcraft
DBX
Dyna
Uher
Yamaha
Group 128
SAE
Teac
Telex
Winlab
Schweitzer
ro
Vaco -Rac
<o
(continued)
www.americanradiohistory.com
Neve
THE
QUALITY MIXER
SAN LEANDRO:
Taber Manufacturing &
Engineering. 635.3831
Ampex
Scully
Electro -Sound
Gotham
Revox
Tascam
UREI
ON
THE ROCKS
STL
Burwen
Inovonics
Electro -Voice
AKG
Russco
Altec
Wireless
Vega
Nortronics
Cetec
Teac
University
Soundoliere
Telex
Crown
SAN FRANCISCO:
McCune Sound. 777-2700
Altec
Jensen
Atlas
Vega
OR
STRAIGHT
Switchcraft
Clear -Com
Shure
3M Tape
Crown
Toa
Koss
UP
Electro -Voice
AKG
Edcor
Telex
Orrtronics
Alembic Inc. 864 -3800
JBL
Parasound
Adolph Gasser Enterprises
495.3852
Nagra
Stellavox
Sony
Arrivox
Sennheiser
Shure
AKG
Vega
NEVE ANNOUNCES THE NEW 8024 CONSOLE. Where else can
you get a 24 track recording and do simultaneous quad, stereo and
mono mix downs?
This
24
track console provides all the flexibility one can imagine
within the astonishing length
80.5 inches.
-
LOOK AT THE FEATURES
24 In /24 Out
Overdub 24 Track
Full EQ on Every Channel
Simultaneous Quad,
Monitoring
Stereo and Mono Mixers Quad Positioning on Each Channel And
for Added Flexibility There are 240 Jacks.
Of course, the Neve quality is built into this console which is
delivered with its own handbook, spares kit, and all mating XLR connectors, and you will be amazed at the low price. Couple this with the
now famous Neve Service and you again have a winning combination.
CALL US
-
Rupert Neve Incorporated, Berkshire Industrial Park,
Bethel, Connecticut 06801 Tel: (203) 744-6230, Telex: 969638
Rupert Neve Incorporated. Suite 616.
1800 N. Highland Ave.. Hollywood. California 90028 Tel: (213) 465 -4822
Rupert Neve of Canada, Ltd., 2717 Reno Road,
Mallon, Ontario L4T 31(1. Canada Tel: (416) 677 -6611
Rupert Neve & Company Ltd., Cambridge House,
Melbourn. Royston, Herlfordshire, SC8 6AU England. Tel: (0763) 60776
Rupert Neve GmbH. 6100 Darmstadt Bismarckstrasse
114 West Germany. Tel: (06151) 81764
Circle 37 on Reader Service Card
Electro -Voice
Nagra
Crown
Atlas
Electro -Voice
Sony
Stellavox
D &M
Uher
AKG
Teac
Tapco
Ampex
Countryman
Edisco. 756 -0300
Shure
Atlas
Lowell
Nortronics
Bogen
Utah
BASF
Electro -Voice
University
Memorex
Sound Genesis. 391 -8776
Advent
Atlas
Crown
Electro -Voice
Langevin
Metrotec
Ramko
Scully
Sony
UREI
AKG
Ampex
DBX
MB
Parasound
Revox
Sennheiser
Soundcraftsmen
Otari
Allison
Beyer
Editall
Gauss
Maxell
Scotch
Russco
Sescom
Tascam
Altec
Countryman
Electro -Sound
JBL
McIntosh
Quad -8
Scott Instruments
Shure
Teac
San Francisco Radio: 863 -6000
Teac
Shure
Telex
Koss
Sony
Sennheiser
McIntosh
Electro -Voice
AKG
Altec
Thorens
Bogen
Brooks Camera. 392 -1900
Sony
Marantz
Uher
Jensen
Teac
Acoustic Research
Technical Sales Associates
467-1434
Oxford
E-V /Game
Permapower
McMartin
Fourjay
Audio -Video Associates.
Lowell
Sennheiser
Frasier
Belden
Cornish
Atlas
Electra -Voice
AKG
Bogen
Columbia
Cannon
Soundoliere
Bozak
Skinner Studios. 986-5040
Sennheiser
Shure
Audio Devices
Magnecord
University
Alpha
Shure
626.2038
Lumiere Productions.
Altec
Crown
989 -1130
JBL
Shure
Atlas
Electro -Voice
McIntosh
Stevenson
Cerwin -Vega
Community Light & Sound
Sennheiser
SAN
MATEO:
Protronics Co. 574-8511
Altec
Teac
B &O
Thorens
Tandberg
Sherwood
Marantz
Alembic
JBL
Ampex
401 Broadway
Redwood City CA 94063
367-2011
60 Brady St.
San Francisco CA 94105
864 -3800
Phillips
Sony
TIBURON:
Gauss
Shure
Vega
MB
AKG
Ampex
McKenzie
McIntosh
Sony
Sony
Tape -A -Thon
Electro -Voice
Wireless
UREI
AKG
Edcor
Fairchild
Sennheiser
WALNUT CREEK:
1BL
ARP
MacPherson Sales Corp.
937 -1482
Toa
Bose
OEM
McIntosh
AKG
Fisher
Superscope
Altec
Vega
Tapco
Teac
Shure
Dather
Innermedia
MRL
999 Commercial St.
Palo Alto CA 94303
327.6724
94140
824.2223
Kinetic Technology
3393 De La Cruz Blvd.
Santa Clara CA 95050
408 -296 -9305
Memorex Corporation
University
Rotel
Scully -Metrotech
475 Ellis St.
Mountain View CA 94040
968 -8389
Countryman Associates
424 University Ave.
Palto Alto CA 94302
326 -6980
FRAP
PO Box 40097
San Francisco CA
Parasound
Tascam
Quantum
Gately
Catania Sound. 479.7043
635 -3831
TenteI
1210 Camden
Campbell CA 95008
408-377 -6588
415-989-1130
Electronic Music Associated
3400 Wyman St.
Oakland CA 946159
532-5034
UREI
TERRA LINDA:
San Leandro CA 94577
Clear -Com
759 Harrison St.
San Francisco CA 94107
Marantz
Spectrasonics
BRANCH OFFICES:
Agfa
1
CA
94005
B &K
1611 Borel Pl.
San Mateo CA
#236
Laboratories
CBS
408 -987-1325
Parasound
680 Beach St.
San Francisco
776-2808
Mill Dr.
W.
Brisbane
1200 Memorex Dr.
Santa Clara CA 95052
Phillips
Edison Ave.
2081
Audio-Tek
2970 Scott Blvd.
Santa Clara Ca 95050
408. 244-1776
Electro -Sound
725 Kifer Rd.
Sunnyvale CA 94086
408-245-6600
Corporate Media Systems.
435.2020
Altec
Sennheiser
Quad -8
Recortec
777 Palomar
Sunnyvale CA 94086
408 -735 -8821
Sound Genesis
445 Bryant
San Francisco CA 94107
391 -8776
Taber Manufacturing & Engrg.
ESS
Shure
Telex
Countryman
Crown
Neumann
MANUFACTURERS
Kenwood
Embarcadero Center
San Francisco CA 94111
1
»495
CA
3M Tape
320 Shaw
South San
94109
Francisco CA
Why does Studio Tempo use the Amber
--.
Audio Spectrum Display?
d I
Studio Tempo uses an Amber Audio Spectrum
Display in their Montreal recording studio.
Michel Lachance, Chief Engineer, explains why:
"I use the display primarily during mixing to
I
prevent problems later on in mastering.
constantly watch the display during a mix to
ensure my tape does not have excessive high or
low frequency energy. If I want to highlight a
particular instrument I can see the effects of
equalization or other forms of processing. The
peak responding characteristics of the display
give far more information about what's on a tape
than a VU meter.
"One very handy thing I use the display for
verification of performance of equipment. I'm
very particular about alignment, and I like to put
a sweep tape on our 24 track before each session,
and read each track with the display. It shows
exactly in dB any response errors and all 24
tracks can be checked in minutes ".
See for yourself. Contact Amber for the name of
a nearby dealer and arrange for a demonstration
in your studio - it really works.
t
1
T.
-4*
\
Circle 38 on Reader Service Card
-.
`
550 Audio
F.mberSn
.040$1- 800 US tisi.
"
Spéitum-Hispla
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AI1tiElt HECTRO DEsic¡N Lrd
1064 clrEMiN du GoLF
MONTREAL QUEBEC CANAdA
13E
1144
w:1) 769 2739
JAMES J. DAVIDSON
Covers Audio Band
In One Sweep
timer can be adapted to create a square-wave
generator which covers the 20- 20,000 Hz range in one sweep
with no band switching.
A 555
handy to have a
generator which covers the entire 20- 20,000 Hz
range in one sweep, with no band switching. The
ubiquitous 555 timer can be adapted to this function, producing 50 percent duty cycle square waves whose
frequency is controlled over a 1000:1 range by a single
potentiometer.
The complete circuit is shown in FIGURE 1. Note two
items: 1. The capacitor is charged and discharged by the
output stage (pin 3), rather than the discharge transistor
(pin 7) as is usually done. That simplifies the frequency
control. 2. A symmetry resistor, Rs, goes from pin 5 to
ground. This resistor adjusts the duty cycle and the prober
value yields exactly 50 percent, as will be explained.
Recall that, for the connections shown in FIGURE 1,
the maximum voltage on the capacitor is the same as that
on pin 5 (V;), and the minimum is half that on pin 5
(IhV,). If we assume that the low voltage from the output
stage (V,I) is approximately zero and leave the high output voltage (V,H) temporarily unspecified, then the charging time for the capacitor is:
OMETIMES, IN AUDIO WORK, it's
t,.
=
RFC In
and the discharge time is:
1/2V,
V,x - V,
Fgure
1.
20- 20.000 Hz square -wave generator.
=
RFC 1n2.
For 50 percent duty cycle, t,, = td, or V,
td
Vc_
=
35 V,H
Now if it were the case that V,H = V, ,., Rs would not
be needed since the internal divider string puts pin 5 at
1/2V. But as the data sheets for the 555 show, V,H is
about 1.4 volts below Vec. Using this value, the formula
for Rs is
V
R(.476V .667)
Rs = R V,
1.5V5 =
where R is specified as 5000 ohms per resistor. For a 5volt supply, Rs = 8.6k to give a symmetrical square wave.
-
James J. Davidson is a consultant with Davidson
Consultants, in Overland Park, Kansas.
The frequency of oscillation, very simply, is
f
-t+
1
1
=
-
.721
2RFC 1n2
RFC
If C = 0.0721 uf, f = 10T /RF.
The frequency determining resistor, RF, consists of a
fixed part of 500 ohms and a variable part of 0.5 megohm.
A log -taper audio volume control gives a much smoother
distribution of frequencies with rotation than a linear taper
would. For a proper sense of rotation, put the frequency
calibration marks on a skirted dial rather than on the
panel. (If that sounds puzzling, try it.) The 500 -ohm fixed
resistor sets the 20,000 Hz frequency. However, check the
minimum resistance of the pot (terminals 1 and 2) and
subtract this from the fixed resistor.
www.americanradiohistory.com
td
COMPARE
ADM'S NRC and the `Usual" Consoles!
When you buy an Audio Designs NRC Console, you get a
professionally engineered unit built to the highest
quality standards. And you are assured of "no hassle"
service assistance whenever you need it. But that's
not all. You get extra performance and features not
usually found in the ordinary console.
Look at the "unusual" extras you get in ADM Consoles
ADM FULL -FEATURED CONSOLES
AUDEX -solid state audio reed switching system
SLIDEX- noise -free linear attenuator with elements sealed against dirt
VUE- Scan -bar graph TV screen for monitoring up to 28 audio channels,
switchable between peak and average reading
4 -band 14 frequency reciprocal equalizer on all inputs
4 sets cf Machine Remotes
Full quadraphonic capabilities with 4 joy sticks
Simultaneous multi -track (8, 16, 24 track), quad, stereo and mono outputs
Complete tip, ring and sleeve patching
4
2
cue channels.
solo systems
5 -Year
Warranty on parts and labor
not the "usual" troublesome push buttons.
not the "usual" open elements (noisy).
not the "usual" mess of meters.
not the "usual" 3 -band.
not the "usual" one or none.
not the "usual" one or two joy sticks.
not the "usual" multi -purpose outputs.
not the "usual" miniature size or
limited patchin D.
not the "usual" one or two.
not the "usual" one.
not the "usual" 90 days to one year.
AUDIO DESIGNS AND
COMPONENTS
S CONSOLES
Write or call collect
for further information
on the UNusual
ADM Console.
MANUFACTURING, INC.
16005 Sturgeon
Roseville, Michigan 48066
Phone: (313) 778 -8400, Cable: AUDEX
Circle 39 on Reader Service Card
In Canada: TELAK
Scarborough, Ont.
(416) 438 -3804
DAVID L. KLEPPER
THE BEST OF
db
Architectural Acoustics, pari 1
By following certain rules, you can design and build, or modify,
studios to meet specific acoustic needs.
Reprinted from db March 1968
TFIE professional worker in audio is involved with
acoustics, regardless of his specialty within his field.
Indeed, the fields of audio and acoustics overlap
more than they are separate and distinct. The acoustics of recording and broadcast studios, theaters, concert
halls, and other performing spaces affect the work of the
recording and broadcast engineer-while the acoustics of any
space requiring an electronic sound amplification system will
affect the performance of the system and the work of the
system designer. installer, and operator.
A theater, concert hall, auditorium, or a radio or television studio should be designed acoustically: first to form
a good room -acoustic link between the live sources of
speech and /or music, and the live listeners and /or micro phone(s); and second to exclude noise. Both the roomacoustics and noise-control aspects of architectural acoustics
have been under continuous development for many years.
The goals of the room- acoustics design may be stated as:
Insuring an even distribution of sound energy throughout the space.
Controlling discrete echoes, rapidly repeating echoes
(flutter-echoes) and bunching of the normal modes of vibration of the rooms which might emphasize certain frequencies.
Providing the proper reverberation time characteristics.
Assuring the proper ratio of reverberant -to -early sound,
related to the shape of the reverberation decay curve and
particularly important in spaces where live music is heard
by live listeners.
Providing a short enough initial time -delay gap, for early
reflections, again important in live -music spaces.
Diffusivity and Echo Control
egi
Even sound distribution and satisfactory control of echoes
and normal modes is achieved where there are no extreme
variations in sound pressure either as the frequency of the
signal or the position in the room is varied. Diffusivity can
be accomplished by avoidance of parallelism in the basic
shape of the room, as in FIGURE 1, or large -scale modulations of basically rectangular shapes, as in FIGURE 2. The
popular polycylindrical diffusers (FIGURE 3) are one form
of "break -up" that can be added to basically rectangular shaped rooms.
Where large, concave or flat surfaces are essential because
of architectural or other planning considerations, echoes
may be controlled by sound -absorbing treatment. Usually,
however, diffusion by surface break -up and shaping should
Figure
1.
A non -rectangular plan
for
a
studic.
be considered first and the sound -absorbing treatment limited
to that required for reverberation control.
Elements added to basically rectangular rooms for sound
diffusion must be approximately equal or larger in scale
compared with the wavelengths of sound energy being controlled. (The wavelength of a 100 Hz signal is 11.3 feet.)
For speech studios a designer might restrict diffusion to the
range above 200 Hz (5.65 ft.), but for music studios the
range down to 50 Hz (22.6 ft.) or even lower to the 20
Hz lower limit of human hearing may be important.
In many auditoriums and concert halls, balconies or applied decoration in the form of statues, etc. are "natural"
sound -diffusing elements.
-
-
Reverberation Time
We define reverberation time as the time required for
sound to decay to one -millionth of its value (60 dB) after
cessation of the sound source. In any real room it usually
varies as a function of frequency and may be predicted accurately by the ratio of the volume of the room to the total
sound -absorption present, according to the following
formula[:
l
This equation is called the Sabine equation after Wallace Clement
Sabine, father of modern architectural acoustics. It appears generally applicable for must diffuse -large spaces, although the Norris
Eyring equation or other modifications of Sabine's original equation
are perhaps more appropriate for small or very dead rooms.
R, (reverberation time)
Where
V
- 0.049
Sa
V= room volume
S= room surface area
a = average absorption coefficient
Sa =total sound absorption
WOOD BRACING
Although early studios were uniformly dead, there has been
a trend from the early days of broadcasting to the present
for more reverberant studios, particularly for music performance.
Beranek's suggested criteria for speech, general, and music
studios still appear to be generally applicable and are illustrated in FIGURE 4. Large music studios should have much
the same reverberation time characteristic as a fine concert
hall. Speech studios should have essentially no audible
reverberation with less or equal reverbation time at frequency extremes (low- frequencies and high- frequencies) as
compared with mid- frequencies.
General studios may be a compromise between speech
studios and music studios. Regarding auditoriums for "live"
listeners, experience suggests the following mid-frequency
reverberation times for different uses:
Optimum
Lectures
Drama (theaters)
Musical Comedy
Opera
Instrumental Recitals
and Chamber Music
Orchestral Concerts
Vocal Recitals
Choral and Organ concerts
(liturgical music the
upper limit depends on
the type of music)
-
0.9 1.1
0.9 -1.4
1.2-
1.5
- 1.8
1.4 - 1.8
1.8 - 2.0
1.5 - 1.8
1.5
RANDOMIZED
TWO LAYERS
THIN WOOD
FELT BETWEEN
9
Possible"
0.5 1.4
0.5 -1.6
-
1.0-
1.7
- 2.0
1.0 - 2.0
1.4 - 2.5
1.4 - 2.0
1.4
Figure 3. Typical polycylindrical diffuser construction.
The diffusing effect of a cylinder is maximum when
diameter equals one -half wavelength, and a combination
of different radii will provide optimum diffusion over a
wide range. The construction shown also provides low-
frequency absorption.
-
2.0 minimum
1.7 minimum
reverberation time calculation will reveal
"dead" side (too low a reverberation time), even without any applied sound -absorbing
Occasionally
2
Good results possible provided other parameters are optimized.
Figure 2. Sound diffusing wall modulations of several
types applied to a rectangular room.
a
a studio or auditorium on the
treatment. For example, the calculated reverberation time
for a studio planned for music broadcasting may be under
1.5 seconds at mid- frequencies, even with all interior finish
materials hard and sound-reflecting. The reason may be a
relatively low cubic volume (interior volume less than say
40,000 cubic feet), with the predicted sound-absorption of
the 100 members of a full symphony orchestra present.
Economics may dictate the design of studios or halls below optimum size. Under these conditions the wise designer
or acoustical engineer will often refrain from attempting to
make the hall or studio as live or reverberant as possible
within the available volume, because under certain conditions in small halls or studios, he would be concerned that
the space would simply be too loud for proper performance
conditions. Instead, particularly in studio situations, he
might choose to provide a relatively dry acoustical environment to be supplemented by electronic reverberation devices,
either within the hall itself (for performers, listeners, and
recordings) or for recordings alone.
We have been discussing mid -frequency reverberation
time goals for various spaces. These are reverberation times
measured in the 500- 1000 Hz range. The variation in reverberation as a function of frequency is also very important; and it is a good measure of the "frequency response"
of the room. For example, a concert hall with a reverberation time of 2.8 seconds at 125 Hz, 2.0 seconds at 500 and
www.americanradiohistory.com
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-
ó 2.5
/j
-/
//
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(Mozart Haydn) and contemporary (Stravinsky) music.
Rather than shorten the reverberation time to obtain the
added clarity, today's acoustical engineer would rather supplement the direct sound with additional sound energy that
arrives at the listeners' ears soon enough to reinforce the
direct sound, adding to clarity without destroying the richness of a long reverberation time. The goal is a "have your
cake and eat it too" solution, which combines clarity and
reverberation. Such a hall can have a large-hall liveness of
sound with a small-hall intimacy. The time of arrival of
these early reflections and their strength is important. If too
late (after the initial sound) or too low in strength, they
will be ineffective in aiding clarity: if they are too strong
and early enough they will so dominate the sound heard
by listeners that the liveness of the hall simply will not be
heard, and the hall will have a reputation for dryness despite
an adequately long reverberation time.
These early reflections may be compared to a pinch of
pepper in a well -prepared soup. Just the right amount is
needed. Too much and we'll taste only the pepper (too much
clarity); not enough and the pepper may as well be absent
(too little clarity); and the pepper should be added at the
right time for best effect (the proper initial time delay gap).
The amount of energy in the early reflections, together
with the energy of the direct sound, determines the ratio of
early -to- reverberant sound, while the timing determines the
"initial time delay gap ". The ratio of early-to- reverberant
sound is for our purposes, defined as the ratio of sound
energy received at a listener's position for the first 50 milliseconds during and after the receipt of the initial pulse of
sound to the total sound energy received after the first 50
milliseconds.' Often, the inverse ratio the ratio of rever-
-
-
A%///////,%//////.%%
%//
/i%
/4
1"'i
ir05
%/////,//,%/,r.
0
2
50
4
8
500
100
2
1000
4
8
5K
10K
FREQUENCY IN Hz
-
Figure 4. Suggested studio reverberation criteria.
3
1000 Hz and 1.6 seconds at 2000 Hz would be characterized
as warm. On the other hand, a similar hall with reverberation
times of 1.5 seconds, 2.0 seconds, and 2.0 seconds at 125,
500 -1000, and 2000 Hz, respectively, would probably be
characterized as harsh, or bright. Today, acoustical engineers plan large halls or studios for music performance to
have rising low- frequency reverberation time characteristics:
that is longer reverberation times at low frequencies than at
middle or high frequencies.
In a speech studio, particularly a small one, a longer reverberation time characteristic at low frequencies would be
characterized as a boomy acoustical environment. Speech acoustics spaces should generally have flat reverberation time
characteristics. Studios and auditoriums planned for both
speech and music may be planned as a compromise, or
as discussed earlier adjustable treatment or electronics may
be employed to bridge the gap between optimum speech and
optimum music conditions.
-
-
We assume use of a short -duration (5 milliseconds or less) pulse or
impulsive sound source to obtain measurements of the quantities
here discussed. Such sound sources would be analogous to transient
sound in speech and music the attack of a musical instrument or
consonants in speech rather than the stead -state or vowel sounds.
Proper hearing of transients is necessary for adequate clarity.
-
-
+10
CLOWES HALL
INDIANAPOLIS
+5
0
LA GRANDE SALLE
MONTREAL
5
Initial Time Delay Gap and Ratio of
Early -to- Reverberant Sound
These quantities have been analyzed primarily with respect to concert hall acoustics although there is every indication that we should consider them important in large
speech halls also.
In a large concert hall having an "ideal" reverberation
time characteristic (a long one, say 2.0 seconds) there can
be a tendency for the sound heard by a live audience to be
muddy or lack sufficient clarity, particularly for classic
-
10
2
100
4
8
500
2
1000
4
5K
810K
FREQUENCY IN Hz
Figure 5. Ratio of reverberant sound energy to early
sound energy of modern halls, expressed in dB (10
log o) as a function of frequency.
www.americanradiohistory.com
The BeogramTM 4002. If you are serious about your audio system, there is no alternative.
The Beogram 4002 began when Bang &
Olufsen engineers were told to set aside the
traditional solutions to turntable design and
begin anew. Their goal was simply stated:
Develop an electronically controlled turntable with optimum specifications. The
result of their work was the Beogram 4002.
an audio component unequalled in both concept and performance.
The cartridge. The quality of any turntable
is easily negated by using an inferior or mismatched cartridge. Bang & Olufsen engineers felt it was essential to develop a cartridge which was an integral part of the turntable and not simply an appendage added
later by the user. Therefore, an entirely new
cartridge was developed which could meet
the specification levels set for the turntable.
This cartridge was the MMC 6000: a brilliant piece of miniaturization capable of
reproducing a frequency spectrum from 20
to 45.000Hz. The MMC 6000 features the
new multi -radial Pramanik stylus for exceptional high frequency tracing and has effective tip mass of only 0.22mg. It has a tip
resonance point of over 45,000Hz, a compliance higher than 30 x 10-". and a recommended vertical tracking force of I gram.
tial tracking effectively eliminates tracking
error and skating force. When a record is
being played. each revolution brings the
stylus one groove's width closer to the center. This inward movement causes the tone
arm to pivot the equivalent fraction of a
degree and reduce the amount of light received by a photocell within the tone arm's
housing. This causes a servo motor to very
slowly move the entire assembly the exact
distance required to compensate for the
angular deviation. Precision, low- friction
A color brochure presenting all Bang & Olufsen products
in detail is available upon request.
Bang &Olufsen
Fine instruments for the reproduction of music.
The tone arm assembly. The Beogram 4002
features one of the most sophisticated tone
arm assemblies ever developed. Its tangen-
Bang & Olufsen of America, Inc.
2271 Devon Avenue
Elk Grove Village. Illinois 60007
ball bearings keep the vertical and horizontal
friction of the tone arm to between 5 and
15mg. As the toile arm is always kept tangent with the record groove, skating force
is eliminated.
Operation. The Beogram 4002 utilizes computer logic circuits for automatic control of
the operation cycle. Once you have depressed the "on" switch further assistance
is unnecessary. The detector arm preceding
the tone arm senses the presence and size
of the record and transmits the appropriate
information to the control unit. If there is no
record on the platter, the arm will be instructed to return to the rest position and
shut off the unit. When a record is detected,
the correct speed is automatically set and
the stylus cued in the first groove. A patented electro- pneumatic damping system
lowers the tone arm at a precise, controlled
speed to prevent damage to the stylus. The
entire cueing cycle takes only two seconds.
The control panel of the Beogram 4002 also
permits power assisted manual operation.
You may move the tone arm in either direction and scan the entire record at slow or
rapid speed. A slight touch on the control
panel will lower the arm exactly in the
groove you have chosen: another touch will
immediately lift it for recuing elsewhere.
During any operation, either manual or automatic, you need never touch the tone arm.
Bang & Olufsen components are in the permanent design collection of the Museum
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www.americanradiohistory.com
of Modern Art.
4)
V
e
F
A
Figure 6. A 3000 -seat Concert Hall -Opera House and 1700 -seat Recital Hall- Theatre Combined in One Hall. (A) -Planleft stage enclosure in position for 3000 -seat concert hall, right, 1700 -seat theatre, stage enclosure stored. (B)- Longitudinal section, stage enclosure in position for 3000 -seat concert hall. (C)- Longitudinal section, stage enclosure
stored for 1700 -seat theatre.
1' -Fixed Balcony Seats 2
Seats 3 and 3' -Stage Apron
Elevator 4 -Fixed Auditorium Walls 5 and 5'- SoundTransparent Movable Auditorium Walls 6 -Fixed Audi1
-Fixed Orchestra Seats
and
2'- Movable Orchestra
torium Ceiling 7- Movable Auditorium Ceiling 8 -Movable Stage Enclosure, Walls and Ceiling 8'- Movable
Stage Enclosure Walls, Recital Position 9 -Stage Teaser and Tormenter 10- Proscenium Pull -out Panels
Shaded areas are spaces closed off by movable ceiling and rear walls.
berant -to-early sound energy is used. The ratios are usually
expressed in decibels rather than fractions. FIGURE 5 shows
the ratios for two modern halls as a function of frequency.
The initial time delay gap is the delay between receipt of
the initial sound and the receipt of the first reflection.
Beranek's study (see Ref. 4) has indicated 0 to 20 milliseconds as ideal for the initial time delay gap, and up to 30
milliseconds as good.
The proper early -to- reverberant sound ratio and the initial time delay gap were inherent in the design of the older.
narrow, rectangular "shoe box" concert halls. The designs
included broken -up or diffuse side walls. spaced sufficiently
close together (and to the halls' center -lines) to provide the
required early reflections. However, the newer, larger and
sometimes more radically shaped wide halls seem to require
supplementary sound-reflecting clouds (Tanglewood; Clowes
Hall in Indianapolis; Jones Hall in Houston; La Grand
Salle, Place des Arts, Montreal; DeDolan Hall, Rotterdam;
for example) or one large sound reflector per hall in the
form of a "lip" (Saratoga Springs; Chandler Pavillion, Los
Angeles; Opera House, Seattle) to assure the right balance
between clarity and liveness.
The recording engineer may not be overly concerned with
these balances. Given a sufficiently live hall, he can increase
clarity by closer microphoning or use of more directional
microphones; or increase liveness by use of more omnidirectional microphones or greater distance from source to
microphones.
The sound -system designer may broaden his understanding of room acoustics problems to have a better grasp of
the combined room -sound system results. In special cases.
where architectural means are impractical, an electronic
sound reinforcement system may be called upon to simulate
early reflections by amplified sound.
theatrical rigging system, with the walls in the form of interlocking self- supporting pieces or rolling towers. There is a
trend, however, to mechanized stage enclosures that reduce
dependence upon normal stage -hand labor for erection and
striking while freeing the rigging system completely for its
prime purpose of storing scenery. In the Jesse H. Jones Hall
for the Performing Arts. Houston. Texas, the forward ceiling panels of the stage enclosure fold down as one unit from
the stage house wall above the proscenium, the side -walls
fold out from the stagehouse walls on each side of the stagehouse, and the rear wall and rear ceiling fold out from the
lower up -stage (rear stagehouse) walls. All this is accomplished with the help of push-buttons and electric motors.
Such a theater design can free the acoustical designer toward
the use of adequately heavy materials, regardless of their
weight. In this case, 12 gauge steel, backed with damping
material and faced with thin wood veneer was employed.
The surface weight of the combined structure is close to 7
lb. /sq. ft., assuring good sound reflection down to 25 Hz.
The improvement of an existing mutlipurpose theater concert hall by provision of a properly designed stage enclosure, whether wood, plastic, or damped metal, is a
familiar event today. Often the improvement in hearing
conditions for the live audience is matched by improvements
in liveness and balance in the sound as picked up by microphones; however, more often than not complete re- engineering of the microphone pickup arrangements are required if
best results are to be obtained.
Stage Enclosures
Auditoriums used for opera and plays usually have generous fly -space over the stage and side -stage areas to permit
movement of scenery and curtains. These voids can act as
traps for sound energy during live music performances; the
proscenium (stage opening) acts as a barrier between the
musicians on the stage and the audience. A music studio or
concert hall surrounds an orchestra with many hard, sound reflecting surfaces. Movable stage enclosures accomplish the
same results in multi -purpose auditoriums, they help in the
"quick- change act" between theater and concert hall. When
in place, the enclosure assures that the audience and performers are in the "same room ".
To be fully efficient, such enclosures should usually be
constructed of fairly heavy material, usually weighing 2
lbs. /sq. ft. or more, to reflect low-frequency sound energy
which can pass through thin, lightweight material. Half -inch
or three -quarter -inch plywood is a popular material for stage
enclosures, both custom -built for particular halls and available from stock from several manufacturers.
Good critical reviews have greeted concerts performed
within relatively lightweight enclosures. These enclosures
employ a process which has been described as selective
absorption to achieve optimum frequency response and instrumental balance. Gaps are left in certain areas of the
enclosure to absorb middle and high- frequency energy, balancing the absorption of bass energy by thinner than usual
material.
The usual system for the erection of a movable stage enclosure is for the ceiling pieces to be suspended on the
listen
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1
AMPLITUDE STATISTICS (SPECTRAL O.STRIRUTION1
/
20
S
ED
EAST
30
NEbbk
Q
/
IIELIO
-10
SLOW
40
AT RECORD EQUAL.
0
IN
FREQUENCY
IOK
20N
IK
INN,
Figure 1. Typical high frequency losses of a constant
current recording (no record pre-emphasis) well below
tape saturation.
li
10N
-20
20N
Figure 2. Amplitude statistics (spectral distribution).
JOSEF W. DORNER
Why Use 15 -ips
Tape Speed?
Is 15 in. /sec. tape sometimes an extravagance when
measuring frequency response? Points in favor may help
you make a logical, and most economical, decision.
A
TEVYE the dairyman's world, audio procedures, young as they are, have already established their traditions. One of these is the practice of measuring a tape record's frequency
response some 20 dB below full modulation, in order to
avoid the possibility of tape saturation at high frequencies
as the result of the high- frequency boost required in the
recording process. Iconoclastic audio engineers might ask,
if the specification sheets for recorders running at 71/2 and
15 in. /sec. show almost identical performance data, why
use twice as much tape at 15 in. /sec. if the same results
can be obtained at 71/2 in. /sec. anyway?
The answer is not, as Tevye melodiously put it. "Tradition." It's not even as your mother might have said,
"Because." This particular practice is based on sound reasons (pun unintentional).
First, we may ask, "Is there really a difference in quality between a 71/2 and a 15 in. /sec. recording, and if so,
why ?"
0
sIN
Josef Dorner is an audio engineer in Zurich, Switzerland
Let's consider record and playback equalization, the
electrical transfer characteristics of the amplifier, which, if
properly adjusted, will produce a linear over-all frequency
response with a given recording tape. If such equalization
were not used and a recording made with constant audio
current passing through the recording head over the whole
audible frequency range, the output would remain constant
at first. But as higher frequencies were approached, a
drooping response would become evident. This fall -off of
high frequencies would be more severe at a slow tape
speed than at higher ones. This effect is shown in FIGURE
1. The amount of high- frequency loss depends on a number of variables, including the tape; therefore, the curves
represent only the general trend and are not to be taken
as absolute figures.
COMPENSATING FOR LOSS
This loss at high frequencies is a wavelength-dependent
effect. The wave length of a given frequency becomes
shorter on tape as tape speed is reduced. Record equalization is used to compensate for this loss of highs. An increasing amount of current is pushed through the head
with rising frequency and decreasing tape speed. That is
possible, to a certain degree, because high-frequency
sa----------,
)2^
500 ,Hz
0
[`.
3:
THIRD
1
/
i0N/15.c1
200
t4_
BELOW LEVEL
OE
0
3%
320nWO/m
20
101u7 s
LauaLE
u+
B
0,
!
.
Figure 3. Frequency response at different speeds and
different levels.
o
----10
o
+i0
,AMPLE
A
SAMPLE
B
L__,
+20
INPUi
Figure 4. Saturation characteristics at high and low
frequencies for different speeds and different modern
high -output low noise oxides.
sounds in voice and music have rather low energy levels.
They may be lifted up to produce on tape a level of
magnetization which is stronger than their presence in a
live performance. Compensation becomes effective for the
losses which occur in the magnetic recording and playback
process, maintaining the same spectral energy distribution
as an over -all effect. To avoid tape saturation, the emphasis must not exceed the amount by which the high frequencies are present at a lower level in the original sound.
Based on various measurements, a curve (FIGURE 2)
has become widely accepted and is considered representative of the average intensity levels in a wide variety of
live sounds (spectral distribution.) The inverse of that
curve is taken to be the maximum permissible record
equalization for any recording process.
However, various researchers1.2 have shown that spectral energy distribution may vary widely, in some cases
being flat up to 16 kHz, within 3 to 5 dB. Obviously, the
record equalization that must be used for music with such
a high energy content at the treble frequencies will drive
the magnetic oxide into saturation.
We can simulate this by trying to run a frequency response on a recorder, not at the conventional level of -20
dB but at a peak recording level instead. The results will
reveal an interesting insight into what actually happens to
the frequency response of a recording at different speeds
and at different levels of magnetization.
STUDYING OUTPUTS
In FIGURE 3, we see the graphic presentation of a typical
performance obtained with modern high- output tapes on
a high -quality tape recorder. From these graphs, one can
conclude the following: A slow speed recorder will drive
the tape into saturation at comparatively low levels; musical selections with high intensity of high- frequency sounds
cannot be recorded without severe losses at the upper spectrum. A recording tape may have reduced saturation characteristics at short wavelengths, causing high- frequency
saturation to occur much sooner than on other magnetic
oxides. (See FIGURE 3, samples (A) and (B) at -15dB.)
Not only the frequency response has to be considered
in such an evaluation, but some difficult -to- measure distortion products are generated when saturation is reached at
high frequencies, causing the recorded sound to take on
a fuzzy quality as a result of the different intermodulation
products which are generated.
COMPRESSION EFFECT
By investigating a tape's transfer characteristic at long
wavelengths, we see that a compression effect (about 0.6
dB) becomes evident at a level which corresponds to the
universally tolerated maximum of 3 percent of third harmonic. At the point where 1 dB of compression is reached,
distortion already measures 12 percent. At the high frequencies (e.g. 10 kHz) distortion products are difficult or
impossible to measure because the limited frequency response of the replay electronics does not normally allow
the determination of their third harmonic content. That
leaves only one alternative, to consider the point of 0.6 dB
compression at 10 kHz as the highest tolerable modulation
level. On the two tapes under investigation, that point
was only a few dB below the 3 percent distortion mark
for 500 Hz when using the speed of 15 ips. At 71/2 ips,
however, the tapes began to show compression (distortion)
at 10 kHz at a much lower level, as can been seen in
FIGURE 4.
Attempts are being made by at least one national standards organization to express a recording system's high frequency saturation performance in terms of a decibel
value for its signal -to -noise performance at a specified frequency. More accurate tests, such as the recording of two
closely spaced high frequencies at different levels of magnetization while measuring their third -order product, will
also yield very useful information.
In any event, it is apparent that the special characteristics offered by modern magnetic oxides should be carefully weighed against such desirable features as improved
signal -to-noise ratio and extended frequency response, if
the risk of high- frequency overmodulation is to be kept as
low as possible. The purpose of using 15 -ips tape is not
just a caprice, or because someone else does it. It is necessary for that margin of excellence necessary to preserve
on tape all the sparkle of a live performance.
REFERENCES
1. McKnight, John G., "The Distribution of Peak Energy,"
Journal of the Audio Engineering Society, April 1969, p. 65.
2. Bauer, Benjamin, "Octave Band Spectral Distribution," AES
Journal, April 1970, p. 165.
A
STUDIO
STUDIO 22
21
FIBERGLASS BOARD
Y".
3
TWO SHEETS
3" ELASTIC PAD
PLAS'ERBOARD
!
FORMEOARD
FIBE RGL ASS
Fg3ERGLASS BOARD
CEILING
JOIST
STUDIO
.4
Z
11
TWO SHEETS PL ASTERBOARD
Figure 1. Cross -section of
studio complex, showing a
floating concrete floor.
}t
STUDIO
12
HEETS PLASTERBOARD
FLOATING CONCRETE FLOOR
a
S
CEILING JOIST
'SS
M.
.
S
---
FORMBOAR D
FIEERGL ASS
Recording Studio
Acoustics, Part 6
Attenuation of noise from exterior sources, such as air conditioning equipment, overhead noise, and traffic requires
careful structural modifications.
MICHAEL RETTINGER
Part 6 concludes db's series, Michael Rettinger's
"Recording Studio Acoustics." Mr. Rettinger is an
acoustical consultant in Encino, California.
IS severely limited, two or
three recording studios of different volumes are
preferable to one large studio with variable volume. Reasonably acceptable proportions for
height, width, and length cannot be maintained for all possible studio volumes by moving one wall or by lowering
the ceiling of the room. When massive movable walls or a
massive ceiling are employed to achieve a low noise level
in the enclosure, the cost of the moving mechanism becomes very high. The acoustic treatment cannot be optimally distributed for all possible volumes unless a second
mechanism is employed to change the acoustic treatment
along with the volume.
Multiple studios may be horizontally or vertically disposed. In either case, each studio should have a floating
floor, that is, a resiliently supported concrete slab, for efficient sound and vibration control.
EXCEPT WHERE SPACE
FLOATING FLOORS
FIGURE 1 shows a cross -section of an elaborate studio
complex for a government project in Ryadh, Saudi Arabia.
A floating concrete floor, besides acting as a second bar-
PRE LOCATED EQUIPMENT
PRELOCATED EQUIPMENT
/ MOUNTING HOLE S
MOUNTING HOLES
WELDED STRUCTURAL -BEAM
INTEGRAL BASE
INDIYIDLA. WELDEC STRUCTURAL
WIDE FLANGE (R :-BEAMS
1
(INTEGRAL
FAN, &
MOTOR BASE SHOWN)
HEIGHT REDUCING
MOUNTING BRACKETS
FIBERGLASS NOISE/
ISOLATION PADS
PADS
SPRING ISOLATION MOUNTS
Figure
2.
HEIGHT REDUCING
MOUNTING BRACKETS
"101SE
S
SPRING ISOLATION MOUNTS
Structural rail equipment bases.
rier for airborne sound, also represents a type of inertia
block which absorbs the mechanical vibrations of impulsive
disturbances like footfalls, the moving of furniture or instruments, etc. Because of the elastic support below the
floor, such a floating slab behaves as a low -pass mechanical
filter whose cut -off frequency is given by
= 3.13/ (d) 1/2,
where d is the static deflection, in inches, of the compliant
mount below the floating floor upon application of the
concrete slab load.
In the case of a studio 30 ft. wide and 50 ft. long, 1,500
sq.ft., a 4 -in. thick concrete floor will weigh 75,000 lb., or
50 lb. /sq.ft. A 2 -in. thick, 3 x 3 -in. Neoprene, cork, or
precompressed plastic -jacketed fiberglass pad may be
loaded to 20 lb. /sq.in., or 180 lb. /pad. Hence 75,000/180
= 416 pads will be required. They may be spaced 2 ft. on
center, with 16 pads along the width and 26 pads along the
length of the floor. Considerable steel reinforcing rods will
be necessary to prevent cracking of the concrete floor,
which may also necessitate several expansion joints. The
concrete should be poured on a sturdy formboard, such as
a 3A -in. thick exterior plywood on which a waterproof
plastic sheet has been placed to prevent water -infiltration
into the wood.
f
RESILIENTLY HUNG CEILING
Another structurally isolated sound barrier is represented
by a resiliently hung ceiling. Much in the manner of elastic pads spaced at 2 -ft. centers under a floating concrete
floor, a gridwork of channel iron and metal lath is hung
by means of spring or Neoprene hangers from the overhead structural building slab. The lath is then plastered,
generally after some fiberglass material has been placed
above the lath for sound absorption in the space between
slab and ceiling.
The cheapest footfall attenuator from an upper to a
lower studio is undoubtedly a thick carpet with an equally
thick underlay. The disadvantage of such a floor treatment
lies in the fact that no strong first reflections from musical
instruments can be had from such a covering. To lay plywood panels on the carpet near an orchestra shell is merely
a makeshift procedure. Such a device is simply an improvised floating floor, without aesthetic appeal and of dubious
quality acoustically because of the high damping.
thick concrete block outside boundary and a studio with
double-stud walls reduced the noise from a near jet -aircraft run -up operation to complete inaudibility in the
studio.
The construction must be carried out properly. Not to
plaster a concrete -block wall is to invite unexpected high
sound transmission through it. Even painting such a wall
has increased its sound insulation by as much as 6 dB over
the entire audio frequency range, and plastering it on both
sides has increased it by 12 dB over the same range. Concrete blocks are rarely sufficiently dry when they are delivered to the job. Shrinkage is bound to occur with consequent openings in the wall, particularly at the joints,
which by themselves are often so porous it is possible to
blow cigaret smoke through them. Every core in every
block, not only every second or third core, must be filled
with concrete to obtain the necessary surface density for
the wall, together with the required seals.
Corridors should be constructed in the same way as
studios if they are to act as effective sound attenuators.
Thus, their floors should be floated on elastic pads, their
ceilings should be resiliently hung from overhead structural slabs, and a generous amount of sound -absorbent
material applied to both the ceiling and the walls. Rubber
pads should be placed on the floor to attenuate the sound
of footfalls and the trundling of carts.
(continued)
FAN
90 dep
85.8 dB
S
V
30
WL
SPL
SO FT
22,000
CU. FT
90 dap
85.8 dB
/MIN
100 FT
40 FT
V
T
10,000 CU. FT.
5 SEC AT 250 HERTZ
REWIRED WL: 47.5 dBp
STUDIO
MULTI -STUDIO CONSTRUCTION
In multi- studio construction, corridors often can be
placed advantageously to act as highly effective sound
attenuators. In one instance, a corridor between a 12 -in.
W L
SRL
-0
Figure
3.
REQUIRED SPL
Duct -silencer.
www.americanradiohistory.com
34dß
AT
250 HERTZ
w
AIR -CONDITIONER VIBRATIONS
Solve all studio timing
problems with ingeniously
simple, low- priced digital
timers from...
r
ES-300
15
530
ES-302
ES
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ES-400
ES-510
In large studio installations, the location of the air-conditioning system equipment often becomes a critical problem. This situation is made more difficult because of the
almost conspiratorial silence regarding machinery vibration
levels on the part of equipment manufacturers. On more
than one occasion, I have had to check the disturbances of
an existing installation employing the compressors or chillers for the planned studio to be able to arrive at the necessary vibration isolation measures. When no such investigation is possible, it is advisable to over -engineer the attenuation. That may save extraordinary expense at a later
date, if it is found that the equipment is audible in the
studio.
My experience is that for most installations, the air-conditioning system machinery near the studio must be placed
on inertia blocks. These should be mounted either on very
tall springs (to achieve, sometimes a required 3 -in. static
deflection) or else on pneumatic mounts with an automatic
feedback of air into the bags in case "bleeding" should occur over a prolonged period. Never place tall springs directly under equipment; that causes a wobbly motion on
part of the machinery. They should be placed under a
cradle, a heavy metal bar with upturned ends under which
the springs can be located to produce a low center of
gravity (FIGURE 2).
Needless to say, the use of an inertia block which may
weigh several times as much as the machinery on which
it is to be mounted requires consultation with the structural engineer of the studio project so that he may specify
sufficient steel in the floor support.
SOUND POWER LEVELS
As good practice, one describes the noise of air-con-
minute up /down timer with incandescent digital display 8 momentary
pushbutton controls on top of an etched aluminum case.
ES -300: A 100
DIMENSIONS: 234" high
8" wide x 5 3/4" deep
60 Hz l0W max.
x
ELECTRICAL: 117 VAC
OPTIONS: B,D,G.H.1.KP.O.R.S.LW,Y
ES -301:
Price: 5168.00
Same as the ES -300 except with Planar gas discharge display.
DIMENSIONS: 21/2" high e 8' wide x 6" deep
ELECTRICAL: 117 VAC 60 Hz
7W max.
Price: 5185.00
OPTIONS: B.D.G.H.I.K.P.O.R.S.T.W.Y
ES -302:
Same features as the ES -301 PLUS lever -wheel, fast-set programming
DIMENSIONS: 21/2" high x 10' wide e 6" deep
Price: $238.00
ES-400: Three-digit, ten minute timer in etched aluminum case.
DIMENSIONS: 274" high x 6" wide o 5 4i" deep
ELECTRICAL 117 VAC 60 Hz 8W max.
OPTIONS: 8,0.1,10,O.R,S,T,W
ES -510: Four -digit,
Price: $98.00
sixty minute timer with momentary pushbutton controls and etched
aluminum case.
x 6" wide x 5%"
ELECTRICAL: 117 VAC
60 Hz 8W max.
OPTIONS: B,D,1.10.O.R,S.T,W
DIMENSIONS: 23/4" high
deep
Price: 5125.00
Twelve volt, 12 hour D.C. digital clock in black anodized aluminum case: no
60 Hz Hum- m -m-m.
DIMENSIONS: 474" high a 3 74" wide x 1" deep
ELECTRICAL: 12 UDC
OPTIONS: B.D.E.F.1.K.P.O,R.S.W
Price: 5200.00
ES -132:
ES -132 except 24 -hour, military time.
Price: 5200.00
twelve-hour. six digit, combination clock /timer with five action momentary
pushbutton controls: etched aluminum case.
DIMENSIONS: 234" high x 8" wide x 5 44" deep
ES-
134: Same as the
ES -500: A
ELECTRICAL: 117 VAC 60 Hz
OPTIONS B.C.OJ.KP,O.R,S.W
12W max.
Price 5150 00
-
OPTIONS
Output
Crystal Timebase
220 VAC, 50 Hz
Nit
19" Front Panel. 31/2" high
9" Front Panel. 31/2" high
Remote Connector
Slave
Tenths of Seconds
Three Wire Cord and Molded Plug
Relay Contact Closure at Zero
BCD
0
E
G
H
g
Remote Connector, 6' Cable and
Pushbutton Set
AC Operation with Crystal
Timebase
AC Operation with Line Frequency
Timebase
Stop at Zero
Relay Contact Closure and Stop
at Zero
P
0
R
s
T
w
Y
Call or Write for our catalog of Timers. Counters. Measurers. Programmers. Clock
and Simple Solutions To Custom Problems.
1
TS116-
vv
505% CENTINELA
INGLEW00D, CA 90302
(2131 674-3021
Reliable, Simple Products Designed
ditioning equipment in terms of octave -band sound power
levels to make the rating independent of distance and
thereby to facilitate the acoustic design of the installation.
Because both the sound -pressure level SPL and the power
level WL are expressed in decibels, the latter are noted as
dBp's, the p standing for picowatts (10-2 watts) as the reference level. A numerical example will illustrate the use
of this system.
Assume a fan with a WL of 90 dBp in the octave whose
mid- frequency is 250 hertz. This fan has a 30- sq.ft. S -port,
S, capable of delivering 22,000 cu.ft. of air per minute. A
100 -ft. -long unlined duct of the same cross -sectional area
is to be connected to the fan. At the other end of this
main feeder, the duct branches off into a 40 -ft. -long, 3sq.ft. duct to deliver 2,200 cu.ft. of air /min. at a WL of
47.5 dBp into a studio with a volume V, of 10,000 cu.ft.
and a reverberation time, T, of 0.5 sec. at 250 hertz.
What are the SPLs and WLs at the various points, why
the 47.5 dBp, and how can this specification be achieved?
At the port, where WL is 90 dBp, the SPL is:
SPL = WL
10 log S + 10.6
= 90 10 1og30 + 10.6 85.8 dB
At 100 ft. from the port, the WL and SPL are still 90
dBp and 85.8 dB, respectively, because there is no spreading of the sound in the duct. At the branch, the WL in the
3- sq.ft. section will be 10 log(3 /10) = -10 dB less,
or 80 dBp. The SPL will also be 10 dB less, or 75.8 dB. At
the end of the 40 -ft. long line, the WL and SPL are the
same as at the branch end, since the studio is to have a
noise level spectrum of NC -20, with an SPL of 34 dB at
250 hertz, the WL at the ceiling has to be:
WL = SPL + 10 logV
29.5
10 logT
= 34 + 10 1og104 10 log.5 29.5
= 47.5 dBp.
Hence, in the 40 -ft. -long line a duct -silencer with a dynamic insertion loss of 80
47.5 = 32.5 dBp at 250 hertz
is required to achieve NC -20 in the studio (see FIGURE 3).
To
Serve You. Not "Break You."
Circle 41 on Reader Service Card
www.americanradiohistory.com
-
-
-
-
-
-
-
0
o
dassthed
SPLICE FASTER, BETTER, BY SHEARING; replaces razor; attached splicing
tape dispenser; quality workmanship;
reasonably priced; endorsed by professionals. $24.95 prepaid. Guaranteed.
Distributors wanted. NRP, Box 289, McLean, Virginia 22101.
Closing date is the fifteenth of the second month preceding the date of issue.
Send copy to: Classified Ad Dept.
H
db 1
SOUND ENGINEERING MAGAZINE
1120 Old Counry Road, Plainview, New York 11803
for commercial advertisements.
Employment offered or wanted ads are accepted at 25ç per word.
Frequency discounts: 3 times, 10 %; 6 times, 20 %; 12 times, 33 %.
Rates are 500 a word
REELS AND BOXES. 7" and 5" large
and small hubs; heavy duty white boxes.
W -M Sales, 2010 Balboa, Dallas, Texas
75224.
ONE WAY NOISE REDUCTION for cut-
FOR SALE
MONITOR EQUALIZERS for your Altecs
& J.B.L.s are a steal at $75 /channel
ROOM EQUALIZATION with purchase of 1/3 octave filters. This is not
a misprint. Music & Sound, Ltd., 111/2
Old York Rd., Willow Grove, Pa. 19090.
(215) 659 -9251.
S.M.E. Damping Mods -$30.00
FREE
CASSETTE LABELS, blank and custom
printed. Free samples. Tarzac, 638 Muskogee Ave., Norfolk, Va. 23509.
EMS SYNTHESIZERS. Find out how you
can save money on EMS systems. We
promise it's worth your while. Write
EMSA, 460 West St. (S), Amherst, Mass.
01002.
ORTOFON
DYNAMIC MOTIONAL FEEDBACK mono
disc cutting system. Complete amplifier
system: drive, feedback, and feedback playback monitor preamp; rebuilt, original factory parts. Guaranteed. Albert B.
Grundy, 64 University Place, New York,
N.Y. 10003. (212) 929 -8364.
RENT AN 8 -TRACK SCULLY by the day/
week. Contact F. Rubin, (212) 631 -5919.
LEBOW LABS, INC.. 56 Chestnut Hill
Ave., Boston Mass. 02135. New England's foremost pro audio /video distributor, representing over 100 major
manufacturers. Sales, consulting, design, and service by expert staff. Broadcasting, industrial, educational, and recording installations. Frank Petrella,
(617) 337-6303, (617) 782 -0600.
ONE STOP
FOR ALL YOUR PROFESSIONAL
AUDIO REQUIREMENTS
BOTTOM LINE ORIENTED
F. T. C. BREWER CO.
P.O. Box 8057, Pensacola, Fla. 32505
ting rooms /tape copies; retains highs,
rids hiss /surface noise & clicks /pops
by a full 10 -14 dB and costs $150 up
per channel! Music & Sound, Ltd., 111/2
Old York Rd., Willow Grove, Pa. 19090.
(215) 659-9251.
BROADCAST AND RECORDING EQUIPMENT: Scully; Metrotech; Langevine;
Electrodyne; Q.R.K.; Micro -Trak; M.R.L.;
Nortronics; McMartin; U.R.E.I.; Revox;
Crown; Byer; Lamb; Master Room; Stellavox; E.V.; A.K.G.; Sennheiser; Atlas;
Ferrograph; HAECO; Stevenson; Gately;
dbx; Advent; Altec; Fairchild; Audio Designs; 3M; Magnacord; Telex; Inovonics.
Disc recording systems; package deals;
installations; service. Wiegand Audio,
Middleburg, Pennsylvania 17842. (717)
837 -1444.
FOR SALE: TWO (NEW) ELECTROSOUND ES -505C two -track, $2,650.00
each; one Spectra Sonics 502 w /amp,
$180.00; one SS model 403RS power
supply ±24V, $130.00; one SS model
400RS 24V, $125.00. RM Sound 8 Co.
Inc., P.O. Box 72, New Berlin, Wisconsin 53151.
AMPEX SPARE PARTS; technical support; updating kits, for discontinued professional audio models; available from
VIF International, Box 1555, Mountain
View, Ca. 94042. (408) 739 -9740.
FOR SALE: DOLBY M -16, $7,800.00; 3M
206 2500' 2" w /reel & box, $20.00; 1 ",
$10.00 (min. order, 10 reels). Sound 80,
Inc., 2709 E. 25th St., Minneapolis,
Minn. 55406. (612) 721 -6341.
LOWEST PRICES IN THE COUNTRY on
microphones, power amps, speakers,
musical instruments, P.A. equipment.
including Peavey, Heil, J.B.L.; huge
stock, top brands only. Gratin's 110,
606 Rte. 110, Huntington, N.Y. 11746.
(516) 549 -5155.
NEW MODELS: Ampex AG440C 2- track
servo capstan motor; Scully 280B; used
AG440Bs: used Scully 280, 8- track, new
heads, in console, excellent condition:
Sennheiser mics. Immediate delivery
from stock. Malaco Recording, Jackson,
Miss. (601) 982 -4522.
.
I'M BLOWING A DIFFERENT TUNE!
SALE: Bassoon, Polisi standard;
perfect condition, only two years old.
$800.00. Box 61, db Magazine, 1120
Old Country Rd., Plainview, N.Y. 11803.
FOR
FOR SALE: TASCAM 4 -track 701, $1,900;
Tascam 2 -track 701, $1,500; dbx RM157,
$950; Advent Dolby B, $175; custom
consoles, $100 each; dbx 161 compressor, $215; other equipment available.
Call: 301 -933 -9221 or write: Willow
Mill Recorders, 2807 University Blvd.
W., Kensington, Md. 20795.
...
...
if
Now the BEST SELLING
multi -track recorder!
MCI
only from
Audiotechniques, Inc.
in the great northeast!
Tape recorders from
one track to 24 track.
Recording consoles
up to 40 input.
MCI sates- service,
Factory trained technicians.
Studio design and
construction service.
Audiotechniques, Inc.
142 Hamilton Ave.
Stamford, Conn. 06902
(203) 359-2312.
MCI
*
*
*
*
*
SERIES "B" MIXING CONSOLE
VARI -BAND 5 SECTION
PARAMETERIC EQUALIZER
DUAL EQUALIZED REVERB
LONG & SHORT THROW SLIDE
FADERS
HIGH BALLISTIC VU METER
P.O. BOX 3187
HOLLYWOOD, CA 90028
(213) 467 -7890
PRO
LEADING
YORK'S
AUDIO /VIDEO DISTRIBUTOR for
audio, video, broadcast, public address, and hi -fi systems; representing over 130 audio /video manufacturers, featuring such names as
Ampex, Scully, Tascam, Sony, J. B.
Lansing, Neumann, Altec, McIntosh,
AKG, Dynair, T.V. Microtime, UREI,
3M, and other major brands; the
largest "in stock" inventory of
equipment, accessories, and parts;
NEW
competitive discount prices; factory
authorized sales, service, parts, systems design, installation. Write for
free catalog! Martin Audio /Video
Corporation, 320 W. 46th St., New
York, N.Y. 10036. (212) 541 -5900.
MIXER MODULES: modular construction
provides economical route to studio type mixing console; modules available
with mic /line, pan, echo send, plastic
element slide faders; equalization is also
available as an add -on module. Typical
cost of 6 -in, 2 -out mixer (no EQ) is less
than $450.00. Send for catalog. Wall of
Sound, Box 239, Glen Burnie, Md.
21061.
SCULLY, ELECTRO- VOICE, Neumann,
Shure, Spectrasonics, Quad Eight, Masterroom. ARP. Coown, Microtak. Russco.
dbx, Interface, EMT. and others. The
Audio Marketplace, Div. United Audio
Recording, 5310 Jackwood, San Antonio, Texas 78238. (512) 684 -4000.
KING MODEL 800S TAPE WINDER
(hub); pre -recorded tape winder, will
wind either 1/4 in. or 150 mil. widths; as
new condition. Also used Rangertone
resolver, as is. Gary E. Taylor, Continental Film Productions Corp., P.O. Box
6543, Chattanooga, Tenn. 37408.
TUNED ROCK P.A.s Customized
high intensity touring /permanent installation sound systems, including
narrow band (5 Hz!) feedback suppression, detailed regenerative response Acousta-Voicing /environmental equalization (± 1 dB at your
ears), room design /measurement/
treatment, -= 15% articulation loss
of consonants; 1000s of customized
professional products, including fiberglass horns, consoles, comp /rms/
peak limiters, 18 dB continuously
variable electronic crossovers, digital /acoustic delays, omnipressors,
phasors, reverb, echo, doubling/
tripling effects, P.A. noise reduction;
piezo transducers; frequency shifters from: J.B.L. /Altec pro, Tascam,
U.R.E.I., Eventide, Gately, Schoeps,
Beyer, Crown, Community Light/
Sound, Mom's Audio, McIntosh, Bozak, Allen & Heath, etc. etc. All
shipped prepaid /insured. Music &
Sound, Ltd., 111/2 Old York Rd., Willow Grove, Pa. 19090. (215) 6599251.
Inventors /Engineers
2 -track
w /console,
AMPEX AG-440
$2,300; Scully 280 -2 w /console, $2,600;
Scully 280B -2 w /console, $2,995; Neumann VG -2 cutting rack containing: LV60 power amp. GV -2A feedback amp,
SI -1 circuit breaker, WV-1 monitor amp,
plus new ES -59 head, all for $1,400.
Contact Ron or Grant at: Sound Recorders, 206 S. 44th St., Omaha, Nebraska
68131.
AUDIO BEEPER for all audio -visual systems. For information call or write
C-TRONICS, P.O. Box 84, E. Brunswick,
N.J. 08816. (201) 254 -9487.
the sensaAUDIO PRO CLEANER
tional new cleaner that eats up studio
grime, makes your equipment look like
new, cleans heads, tape guides, capstans .
and everything else in the
studio! Send $11.95 for one gallon plus
8 oz. sprayer post paid to: Audiotechniques, Inc., 142 Hamilton Ave., Stamford, Conn. 06902. (203) 359-2312.
.
.
.
.
B.B.C. REFERENCE MONITORS, pre -
monitors;
equalized
J. B. L. /Altec
Dahlquist phased arrays; I. M. F.
transmission lines; Infinity electrostatics; Crown /McIntosh 16 R /bridged
bi -amps; Scully /Revox A -700 recorders; Micmix reverbs; Eventide
phasors /omnipressors; Lexicon digital delays; dbx /Burwen N.R. corn panders; Little Dipper hum /buzz
notch filters; Cooper Time Cube
echo send; moving coil Supex /Ortofon; B & O straight line arms /cartridges;
Schoeps /AKG /Sennheiser
condensers; Beyer ribbons, U.R.E.I.
comp /limiters /crossovers; Gately pro kits; Q.R.K. tt. 1000s more. Music &
Sound Ltd., 111/2 Old York Rd., Willow Grove, Pa. 19090. (215) 6599251.
-. All Shipped Prepaid + Insured
.
WANT TO GO BI -AMP?
DeCoursey Electronic Dividing Networks
are available from $89.10 (monaural biamp) to $205.00 (stereo tri -amp). Price
includes plug -in Butterworth filters; 6,
12, or 18 dB per octave at any desired
cutoff frequency. DeCoursey Engineering Laboratory, 11828 W. Jefferson
Blvd., Culver City, Ca. 90230.
COHERENT CONCERT SOUND -more
than P.A.! We work with musicians to
create an aural environment in concert
that matches studio production. (212)
947-1271.
AMPEX, SCULLY, TASCAM, all major
professional audio lines. Top dollar
trade -ins. 15 minutes George Washington Bridge. PROFESSIONAL AUDIO
VIDEO CORPORATION, 342 Main St.,
Paterson, N.J. 07505. (201) 523 -3333.
GOTHAM AUDIO CORP. LEASED EQUIPMENT SALE. The items listed below
were in use for less than one year and
are therefore guaranteed to perform
like new. STUDER A -80 2 -in. 16 -track
with remote controller + 8 -track conversion kit; STUDER A -80 /2 -in. 4track; STUDER B62 stereo w /console;
DOLBY M -16. For special low prices call
1
(212) 741 -7411.
competitively priced used Revox
A77 decks available. Completely reconditioned by Revox, virtually indistinguishable from new and have the stanA FEW
dard Revox 90-day warranty for rebuilt
machines. Satisfaction guaranteed. Example, A77 with Dolby, $675, plus shipping. Write requirements to ESSI, Box
854, Hicksville, N.Y. 11802. (516) 9212620.
CROWN
WHATEVER YOUR EQUIPMENT NEEDS
-new or used -check us first. We specialize in broadcast equipment. Send
$1.00 for our complete listings. Broadcast Equipment & Supply Co., Box 3141,
Bristol, Tenn. 37620.
MIXERS from $325.00;
equalizer speakers with built -in power
amplifiers; bi -amped systems and complete portable discotheque systems.
Write us for literature. Dealer inquiries
invited. GLI, Box 2076, Dept. D, Brooklyn, N.Y. 11202. (212) 875 -6992.
DISCOTHEQUE
D1200,
M600,
and
M2000;
drives RTR "Monitor" speakers, on
demo now in our showroom. Barclay
Recording, 503 Haverford Ave., Narberth, Pa. (215) 667 -3048.
WANTED
WANTED: AUDIO CONSOLE (MCI, Spec trasonics, Electrodyne) 8/8 or larger).
Must be in complete working order, factory- assembled. Gaff Productions, 1725
S.W. 17th St., Ocala, Fla. 32670. (904)
732-4585.
EMPLOYMENT
AUTOMATED QUAD PANNING
THE UNIQUE AQC SYSTEM (PAT. APPLIED FOR)
CAN DO WHAT HANDS CANNOT
4,8,
16 & 24 INPUTS
VIDEO & AUDIO ARTISTRY CORP
p.o. box 4571. boulder, colorado 80302
(303) 499 -2001
www.americanradiohistory.com
POSITION DESIRED: Recording experienced on A.P.I. and Ampex. Career position desired; wiling to relocate if offer
secure. References. Mario J. Salvati,
271 Third Ave., West Babylon, N.Y.
11704. (516) 893 -0266.
FOR SALE
REPAIR
.;
=4
FOR SALE: STEREO DISC MASTERING
SYSTEM, Neumann transistor VG66 amplifier rack; SX68 cutterhead; AM32b
variable pitch and depth lathe, with
Leitz microscope, playback arm, suction
system and stylus microscope; 2 racks
with 2 Pultec EQPI -A; Fairchild 670 limiter, 2 in. oscilloscope, complete TRS
jackfield, control panel with program
and preview metering and controls; 2
Fairchild 688 amplifiers and 2 KLH4
speaker. Console with Ampex 300 deck.
advance heads and 4 solid -state playback preamps. Best price over $25,000.
Caedmon Records, 505 Eighth Ave.,
New York, N.Y. 10018. (212) 594 -3122.
SCHOEPS tTELEFUNKEN) VACUUM TUBE
CONDENSER MICROPHONES REPAIRED.
Original factory parts8factory calibration of capsules.
BODE FREQUENCY SHIFTERS since
Advanced designs for elec1963 .
tronic music studios and high quality
P.A. systems. New real time performance, synthesizer compatible model
(patented features): $995.00. Anti -feedback and special effects model with
variable frequency shifts, down to 0.5
Hz.: $575.00. Prices f.o.b. North Tonawanda. Delivery: stock to 6 weeks. For
details and information on other models
write to: Bode Sound Co., Harald Bode,
1344 Abington Place, N. Tonawanda,
N.Y. 14120. (716) 692 -1670.
.
64
i0-1
ALBERT B. GRUNDY
University PI., N.Y., N.Y. 10003
(212) 929-8364
NMI%
MODERN RECORDING TECHNIQUES
by Robert E. Runstein. The only book
covering all aspects of multi -track pop
music recording from microphones
through disc cutting. For engineers,
producers, and musicians, $9.95 prepaid. The Great Northern Recording
Studio, Ltd. Box 206, Maynard, Mass.
TASCAM REVERBS -$500; Tascam mixing consoles -$2,350; Tascam 1/2 -inch
recorders -$2,750; Tascam 8 -track recorders-S4,600. All shipped prepaid/
insured, including tree alignment /equalization /bias /calibration. Music & Sound,
Ltd., 111/2 Old York Rd., Willow Grove,
Pa. 19090. (215) 659 -9251.
.
18145, Denver, Colorado 80218.
DYMA builds roll- around consoles for
any reel -to-reel tape recorder. Dyma
Engineering, Route 1, Box 51, Taos,
New Mexico 87571.
FREE
CATALOG 8 AUDIO APPLICATIONS
CONSOLES
KITS S WIRED
AMPLIFIERS
MIC., EO, AC N,
LINE, TAPE, DISC,
Don't let its size or price fool you!
TO -1 SPECIFICATIONS
Frequency response: ±0.1 dB
THD (total harmonic distortion):
less than 0.05%
Frequency accuracy: ±5%
Frequency stability:
2% for temp. 32 -104 degrees F.
Source (output) impedances:
600 ohms ±5% at +4 dBm,
200 ohms ±5% at -56 VU
Current drain: 5 mA with 9V supply
Size: 71/4' x 2" x 1"
Weight: 6 oz. (169 gm)
Consultants in Studio Systems
Engineering. Design and Installation
-offeringA COMPLETE CONSULATION
SERVICE FOR STUDIO
PLANNING AND
CONSTRUCTION
FREE -LANCE RECORDING
SERVICE IN THE
NEW YORK AREA
212 673 -9110
64 University Place
New York, N.Y. 10003
POWER
OSCILLATORS
AUDIO
TAPE BIAS
POWER
Oscillator
Switch selectable frequencies:
30 Hz, 400 Hz, 1 kHz, 15 kHz
Balanced outputs:
+4 dBm and -56 VU into 200 ohms
WORAM AUDIO ASSOCIATES
.
-.
DYMA builds custom studio consoles,
desks, enclosures,
studio furniture.
Dyma Engineering, Route 1, Box 51,
Taos, New Mexico 87571.
SS -1
SPEAKER SYSTEM,
$1,200.00; Audio Research amplifiers:
D76, $700.00, D51, $450.00. (516) 889-
.
Held
Highland, Cleveland, Ohio 44143.
SINGLE EDGE RAZOR BLADES, tape
editing. $23/M. Flyer. RALTEC, 25884
INFINITY
THE LIBRARY
Sound effects recorded in STEREO using Dolby throughout. Over 350 effects on ten discs.
$100.00. Write, The Library, P.O. Box
N
The TO-1 is a new pocket size battery
powered test oscillator specifically designed for testing, aligning, and troubleshooting audio equipment, transmission
lines and systems. It permits testing of
frequency response, distortion, gain,
crosstalk and noise for almost any type
of equipment. Its performance and
specs are of the highest standards, making it an indispensible tool for audio
measurements and maintenance, yet it
easily slips into your shirt pocket!
.
DYNACO RACK MOUNTS for all Dynaco
preamps, tuners, integrated amps. $24.95
postpaid in U.S., $22.50 in lots of three.
Audio by Zimet, 1038 Northern Blvd.,
Roslyn, N.Y. 11576. (516) 621 -0138.
r
01754.
.
3777.
Fimekeeper
Models CMS1, 61, 66: M201, 221, MK24, 26 etc.
Attn: Dan Wolfert.
AMPEX SERVICE COMPANY: Complete
factory service for Ampex equipment;
professional audio; one -inch helical scan
video; video closed circuit cameras;
video systems; instrumentation and consumer audio. Service available at 2609
Greenleaf Avenue, Elk Grove Village,
III. 60007; 500 Rodier Dr., Glendale,
Ca. 91201; 75 Commerce Way, Hackensack, N.J. 07601.
121"-
Designed to feed a 600 ohm line at #4
dBm, the TO-1 balanced output can
feed any patch bay using a simple
patch cord. A calibration curve supplied with the unit indicates the output
level for other load impedances as well.
An internal trim pot provides an additional variation of oscillator output.
For testing purposes, the TO-1 can
be used as any other type of high quality audio oscillator with the additional
ability to truly resemble a floating balanced signal source, with distortion and
noise levels matching the best available
microphone. It is a perfect substitute
for any unbalanced signal source as well.
Since it is battery operated, it can be
used as a portable test oscillator in
practically any field situation. At its
low price, it can be an indispensible
tool in any studio, shop or station.
The TO-1 carries a 1 -year warranty.
To order, send check for $59.95
(includes shipping costs) (N.Y. State
residents add 7% sales tax) to:
TIMEKEEPER
Box 35, Great Neck, N.Y. 11021
SUPPLIES
V
www.americanradiohistory.com
coa people/places/happenings
equipment for educational audio, such
as a new l.e.d. device for transmitting
video and audio information and new
miniaturized audio systems.
KASSENS
MILLER
Harold L. Kassens, former assistant
chief of the FCC Broadcast Bureau,
has become a partner in the consulting
engineering firm of A. D. Ring & Associates of Washington, D.C. Other
partners in the firm, which was established in 1941, are A. D. Ring, Dr.
Frank G. Kear, Howard T. Head,
Marvin Blumberg, nad Ogden Prestholdt. Mr. Kassens is well known in
the broadcast industry because of his
activity in f.m. stereophonic and
quadriphonic broadcasting, as well as
his work in broadcast re- regulation
and broadcast allocations.
Hi fi veteran Paul Miller has joined
Maxell Corporation of America, of
Moonachie, N.J. as product /advertising manager. Mr. Miller comes from
Altec, where he was product manager,
and formerly served with Ampex and
Reeves Soundcraft.
Arthur A. Schubert, Jr. has joined
Ward -Beck Systems, Ltd. of Scarborough, Ontario as director of engineering. Mr. Schubert served in the CBS
television engineering department before coming to Ward-Beck. Previously
to that, he worked in England as chief
development engineer for Neve Electronic Laboratories, Ltd. In his new
position, he will be responsible for
engineering management in the design
and production of Ward -Beck audio
consoles and related products.
The 117th Technical Conference
and Equipment Exhibit of the Society
of Motion Picture and Television Engineers (SMPTE) will be held at the
Century Plaza hotel in Los Angeles,
September 28 to October 3. This will
be the first year in which SMPTE will
hold only one conference instead of
two in order to consolidate costs to
exhibitors. For information, write to
SMPTE Conference, 862 Scarsdale
Ave., Scarsdale, N.Y. 10583.
m
RCA International, Ltd. has established a new regional office in the
CICCONE
TRAUSCH
London, England area to service the
European and African markets. The
office will be headquarters of Commercial Communications Systems
Europe, Middle East, and Africa. It
will be located at Lincoln Way, Windmill Rd., in Sunbury -on- Thames. Patrick J. Murrin has been designated
vice president in charge of the new
-
facility.
A new northeastern regional office,
based in Boston, has been established
by Electro Sound, Inc. The office will
be headed by sales manager Joseph
C. Ciccone. His territory will include
all states from Virginia on the south
to Canada on the north, and west
from the Atlantic seaboard through
Pennsylvania. He will also service Canada west to Toronto. Mr. Ciccone
comes to Electro Sound from the Data
Packaging Corporation and was also
associated with RCA.
Charles Trausch has been named
midwest manager for Capitol Magnetic
Products, a division of Capitol Records. His responsibilities include the
sale of music tape and professional
products manufactured under the
Audio label. Mr. Trausch has been
with Capitol since 1970 and previously
was associated with Totel Systems.
A decision has been reached by
prestigious A & M Records to assign
their long -term quad commitment to
the CD -4 discrete record system. This
came about after considerable experimenting with all three of the major
quad systems. The nod to CD-4 by
A & M is regarded by many in the
industry as a major triumph for the
discrete form as opposed to matrix
quad.
A ten week course in the art of
multi -track recording is being offered
by the Recording Institute of America, 6565 Sunset Boulevard, Los Angeles, Ca. 90028 at forty locations
throughout the country. Students
learn to operate equipment such as
the control console, multi-track recorders, equalizers, limiters, noise reduction units, etc. and receive instruction in techniques of microphone selection and placement, patching, overdubbing, mixing and editing. The
course features a two -week experience
with live 16 -track recording and mix
down sessions.
Focalizing customer services, Bill
Hamilton has been appointed regional
sales manager of the Auditronics Systems Division, of Memphis, Tenn.
Mr. Hamilton will be based in Philadelphia. His duties will include providing assistance to recording studios with
equipment, system design, acoustic design, and financing.
CCA Electronics Corporation of
Gloucester City, N.J. has announced
the appointment of A. W. Trueman
to the position of director of engineering. Mr. Trueman came to CCA from
his own consulting firm. Prior to that
he was with RCA.
Two subsidiaries of Filmways, Inc.
of Los Angeles have been consolidated
to form a new Broadcast and Sound
Services group. Broadcast Electronics,
Inc. of Silver Spring, Maryland and
Wally Heider Recording Studios of
Hollywood and San Francisco, Ca.
will be unified under the same executive direction. The group will be
headed by Andrew Szegda, president
of Broadcast Electronics.
Three educational companies have
bean purchased by International Audio
Visual of Van Nuys, Ca. from Alco
Standard of Pennsylvania. The companies include Standard Projector and
Equipment Company, Electronic Systems for Education, and Educational
Projections Company. The combination of resources from the new companies will be utilized to produce new
H. N. Larkin has been appointed
to the newly created position of vice
president for marketing at the Ampro
Corporation, of Willow Grove, Pa.
Mr. Larkin comes from the Control
Design Corporation. Edward N. Mullin, who has been with the firm since
its inception, has been promoted to
the position of vice president for engineering at Ampro.
Our 8 Tracks on Half-Inch tape
Vs.
Their 8 Tracks on One -Inch tape
With the money you save on ours
you can buy a board to go with it.
Our new Series 70 8 -Track is for people who need a
good, but inexpensive multitrack machine. People with an
8 -track application and a 4 -track budget.
competitors combined. We introduced the design philosophy
of low level, high impedance signal processing in mixing consoles (the first first from TASCAM). And it worked.
The Professional Alternative
The standard in the industry calls for high level, low
impedance, half -track formats. That technology is no secret
(we can give you a high level, low impedance version), but
the point is you probably don't need it. And if you don't need
it. why pay for it?
We pioneered the quarter -track format in multi -channel
recorders and we've probably built more of them than all our
You need it. Now you can afford it.
The true test of what goes on a tape is what comes off;
quality is as much a matter of talent as tools. If you want professional quality and yot.'re willing to work with a tape recorder
to get it, take half the tape width for about half the price of a
one -inch machine and see the Series 70 8 -Track at your
TASCAM dealer soon. For your nearest dealer just call (800)
447 -4700. In Illinois: (800) 322 -4400. We'll pay for the call.
8-Tracks on Half -Inch tape.
The second first from TASCAM.
TEAC 1974
TA SCAM
TEAC PROFESSIONAL PRODUCTS
TEAC Corp. of America, 7733 Telegraph Rd., Montebello, Calif. 90640. TEAC offices in principal cities in the United States. Canaca. Europe, Mexico and Japan.
Sometimes you want
lots of
effect.
ïí
4áa;
"The Mike With Guts"
E -V's New 671
Single -D Cardioid.
Proximity effect. It's that husky bass boost a singer
gets working close to the mike. It's just one of the things
our new 671 does better than other mikes. Make a comparison test. We think you'll find that the 671 provides
greater gain before feedback than the mike you are.using
now -or any competitive mike. You'll also find that our
sophisticated shock mounting assures superior rejection of
handling noise. And it's got all the tough -as-nails ruggedness
you expect from an Electro-Voice microphone.
Som
mes you don't.
"The Clean
Mike :' E -V's
New 660/661
Continuously
Variable-D
Super Cardioid.
Successor to the famed 664 ( "The
Buchanan Hammer "), our new 660/66 minimizes proximity effect to deliver
clear, crisp sound at any working
distance. Frequency response, both or
and off axis, is continuously smooth and
uniform. Rear sound rejection capabilities are excellent. The 660/661 mike
is the one mike for doing the most jobs
best. The same professional performance as our famous RE series at
less than professional price.
The 661 has a high /low impedance switch. The
660 and 671 have no-solder impedance change
that takes less than a minute.
Elecfrol/oice
660 clamo-mounted $72.00, 661 stud- mounted...$75.00; 671...
$68.70 (suggested resale net- slightly higher in western states).
Titian ccxnFany
Electro-Voice, Inc. Dept. 652BD, 686 Cecil Street Buchanan. Michigan 491(
Circle
11
on Reader Service Card
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