User manual | "Room Acoustic Tuning" The Art of Small Recording Studios Audio

the authoritative magazine about high f delity
letEzkelte-,.
STEREO
EQUIPMENT
& RECORD
REVIEWS
ef.p.Aay
NOVEMBER
1968
60e
THE WORLD OF PROFESSIONAL AUDIO: Inside a Major
Recording Studio A New Method of "Room Acoustic Tuning"
The Art of Small Recording Studios Audio Techniques in a
Broadcast Station Plus Regular Features
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KSJR/KSJN STEREO FM RADIO SAINT JOHN'S UNIVERSITY COLLEGEVILLE, MINNESOTA 56321
DIRECTOR OF
BROADCASTING
February 12, 1968
Hermon H. Scott, President
Scott, Inc.
111 Powdermill Road
Maynard, Massachusetts
01754
Mr.
H.
H.
Dear Mr. Scott:
A
We have had some interesting experiences with Scott receivers
that I thought might interest you.
KSJR-FM is a 150,000 watt
stereo station broadcasting from St. John's University.
Seventy-five miles to the south we operate a second station,
KSJN-FM, which broadcasts throughout Minneapolis and St. Paul.
This is a satellite station and as such it receives its programming "off -the -air" from KSJR-FM.
In building KSJN-FM we installed a professional rebroadcast
receiver.
It soon became apparent that the receiver was improperly aligned and that it had several other technical problems.
These problems became so severe that we had to take it out of
service and return it to the factory.
With no auxiliary receiver
available, I suggested to our engineer that we might try using
the Scott 344 receiver located as a monitor in my office.
He
reluctantly agreed and we installed the 344 on Thanksgiving.
Since that time it has operated in an unheated metal building in
its walnut cabinet in weather as cold as 25 below zero, twentyfour hours a day.
We feed our broadcast lines directly from it
and we have not had to tune the unit more than once or twice since
it was installed.
This past week we conducted a survey of our listeners in Minneapolis
and St. Paul and I will list some of their comments:
"The quality of your signal is superb and so are your
musical programs";
"The biggest problem at the beginning
of your operation was the poor quality signal.
With the
solution of the technical problems, you have undoubtedly
the best radio station going";
"The quality of sound
emanating from your station is especially good";
"The
sound here in Minneapolis is especially good".
I
think comments such as the above are particularly interesting in
view of the fact that all of Minneapolis and St. Paul are served by
the signal from one Scott receiver.
A satisfied customer is
our best advertisement
(See Scott's whole range of top -performing, long-lasting
receivers, in both AM and FM stereo, from 55 to 120 Watts)
Sincerely,
William H. Kling
Director of Broadcasting
C3SCOTT
Inc., Dept. 35-11 Maynard, Mass. 01754
Export: Scott International, Maynard, Mass. 01754
H. H. Scott,
Check No. 100 on Reader Service Card
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01968,
H. H.
Scott, Inc.
Vol. 52, No.
November 1968
AUDI()
ARTHUR
P.
SALSBERG,
EDWARD TATNALL CANBY,
PETER RENICH
Successor to
RADIO
,
1l.
PAGING
PROGRESS
Associate Editor
C. G. MCPRouD,
RICHARD CLIFF
Publisher
Marketing Director
Production Manager
Subscription Manager
Behind the Scenes-The Professional Viewpoint
Altec Acousta-Voicing
San Francisco High Fidelity Music Show
History of the Audio Engineering Society
Professional Prognostications
Professional Directory
The Art of the Small Recording Studio
Audio Testing in a Broadcast Studio
Electronic Organs-Part 3
ABZ's of FM-Detectors
8 Bert Whyte
21 Don Davis
26
28 C. G. McProud
30 The Industry
38
50 Joseph Giovanelli
54 Fred L. Zellner
76 Norman H. Crowhurst
82 Leonard Feldman
EQUIPMENT PROFILES
Erath Loudspeaker Systems
Pioneer AM/FM Stereo Receiver
Telex -Viking Stereo Deck
Scott FM Stereo Tuner Kit
60 Models I and VI
64 SX-1500T
68 433
72 LT112B-1
RECORD/TAPE REVIEWS
Classical
Jazz
Light Listening
Tape Reviews
86 Edward Tatnall Canby
92 Bertram Stanleigh
94 Stuart Triff
96 Bert Whyte
AUDIO IN GENERAL
Audioclinic
MINUFZTL ItIa
2
Joseph Giovanelli
Audiotechniques
4 Joseph Giovanelli
What's New in Audio
6
Tape Guide 14 Herman Burstein
Letters 16
Editor's Review 18
Classified 104
Advertising Index 106
AUDIO (title registered U. S. Pat. Off.) is published monthly by North
American Publishing Co., I. J. Borowsky, President; Frank Nemeyer, C. G.
McProud, Arthur Sitner, and Roger Damio, Vice Presidents. Subscription
rates-U. S. Possessions, Canada, and Mexico, $5.09 for one year; $9.09
for two years; all other countries, $6.00 per year. Printed in U.S.A. at
Philadelphia, Pa. All rights reserved. Entire contents copyrighted 1968 by
North American Publishing Co. Second class postage paid at Phila., Pa.
REGIONAL SALES OFFICES: Sanford L. Cahn, 663 Fifth Ave., New York,
N. Y. 10022; (212) 753-8824. Louis Weber, 5201 N. Harlem Ave., Chicago,
HI. 60656: (312) 775-0755. Jay Martin, 9350 Wilshire Blvd., Beverly
Hills, Calif.; (213) 273-1495.
REPRESENTATIVE: Warren Birkenhead, Inc., No. 25, 2-chome, Shiba Hamamatsu -cho, Minato-ku, Tokyo, Japan.
AUDIO Editorial and Publishing
Loudspeaker
Project Engineer
MARY CLAFFEY
FEATURE ARTICLES
HIGH FIDELITY
LARRY SALZWEDEL
R. KENNETH BAXTER
JOSEPH GIOVANELLI
LEONARD FELDMAN
ALEXANDER ROSNER
BERTRAM STANLEIGH
STUART TRIFF
BERT WHYTE
INfiITITt Or
REPORT
SANFORD L. CAHN
HERMAN BURSTEIN
e
by Electro -Voice engineers
Editor
Design
Art Director
Contributing Editors
a
Number 62 in a series of discussions
Est. 1911
N. 13th St., Philadelphia, Pa. 19107
Postmaster: Send Form 3579 to the above address.
Offices, 134
Paging speakers represent one of the more
interesting challenges to the electro -acoustic
designer because of the many limitations
imposed by function. Both size and cost are
restricted. In addition, paging speakers must
be efficient, easy to install, and unusually reliable. In recent months, Electro -Voice paging units have been redesigned to meet
ever -higher standards of performance.
Some of the changes were internal and
subtle, yet most significant in terms of operation. For instance, the thickness of the
front plate of the magnetic structure was
increased to achieve optimum flux in the
gap. The result was reduced leakage, increased total flux, and almost the same flux
per unit area, without the need to increase
magnet weight.
As a result of this change, bass response was
improved down to horn cutoff, over -damping at low frequencies was reduced, and
2 dB higher bass efficiency was achieved.
High frequency response was also improved,
primarily as a result of modifications to the
loading plug. Interferences at the throat
area were reduced by providing a large
number of small entrances between the cavity in front of the diaphragm and the throat
of the horn. This resulted in more uniform
response and an increase of about 2 dB in
high frequency output, plus somewhat extended high frequency response.
In addition to these internal changes common to both the rectangular PA30A and
the PA3OR, the horn shape of the round
PA3OR offers several unique advantages.
Horn flare has been calculated to offer the
proper impedance match while still flaring
fast enough at the mouth to permit frequencies above 4 kHz to be spread more uniformly than is typical. About 15° to 18°
wider coverage is achieved to improve intelligibility over a wider area.
Both speakers are now available with matching transformers built into the base of the
mount. These units offer 5 output levels instantly selected from an externally accessible switch. Both 25 -volt and 70.7-volt
models are offered. The design changes,
while modest in importance individually,
add up to a substantial improvement in
overall performance.
For reprints of other discussions in this series,
or technical data on any E-V product, write:
ELECTRO -VOICE, INC., Dept. 1183A
602 Cecil St., Buchanan, Michigan 49107
geet.
A
SUBSIDIARY
OF GULTON
olc&'
INDUSTRIES. INC.
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Coming in
December
The Commonality of Speaker
Systems and Musical Instrumeñts-Antony Doschek discusses the characteristics of
wind instruments 'as compared to horn speakers.
Twenty (Hi-Fi) QuestionsLeonard Feldman answers the
twenty questions most frequently asked by attendees
at his annual Novice Seminar, presented by him for the
past five years at the New
York High Fidelity Music
Shows.
Build a Presence ControlHere are construction plans
for a simple mid -frequency
tone control that would enable one to "move" a vocalist bn a recording into the
foreground.
Altec Acousta-Voicing, Part
II-Don Davis concludes his
description of a modern
method of "tuning" a room's
acoustic properties with a
practical discussion of how
it's actually done.
... and more
EQUIPMENT PROFILES:
Sony Model STR-6060 AM/
FM Stereo Receiver
Sony Model TA -2000 Stereo
Preamplifier
TEAC Model A-40105 Stereo
Tape Deck
... plus others
ALSO:
Record and Tape Reviews,
ABZs of FM, Audioclinic,
Tape Guide, and other regular departments.
ABOUT THE FRONT COVER:
A forest of microphones partially
masks musicians during a recording session at Fine Recording, New
York City. See candid comments
of Bob Fine on professional recording techniques, starting on
page 8.
Audio clinic
JOSEPH GIOVANELLI
If you have a problem or question on
audio, write to Mr. Joseph Giovanelli
at AUDIO, 134 North Thirteenth Street,
Philadelphia, Pa. 19107. All letters are
answered. Please enclose a stamped,
self-addressed envelope.
Eliminating Skating
Q. My tonearm has no anti -skate
device. My problem is that it is impossible to adjust the tonearm so that
it does not pull slightly towards the
center of the disc. How can I correct
this?-John Donmoyer, Allentown, Pa.
adjust your tonearm
that the inward pull toward the
A. If you can
so
center of the disc is only very slight,
you probably have done all that is
needed. You are luckier than a lot of
us. Some arms cannot be adjusted so
that the amount of inward pull is only
slight. When the pull is severe, the distortion, especially on the right channel, is increased considerably over that
of the left channel. However, if the inward force is only very slight, the
amount of distortion on the right channel will not increase sufficiently to
cause you to hear it or to create excessive record wear.
One scheme to overcome this problem is as follows: It involves a glass rod
mounted just above, and to the right of
the tonearm, near the pivot end. Just
forward of the pivot, tie a piece of
thread on the arm. This thread will
come up over the rod and hang down.
The free end of the thread is tied to a
weight whose amount will depend upon the amount of skating force to be
overcome and, of course, upon the
angle made by the rod and the tonearm.
As the arm moves, the angle made by
the rod and thread changes, thereby
changing the amount of neutralizing
force provided by the weight. This is
exactly what we want to happen, because as the tone arm comes nearer
and nearer to the center of the disc, the
less neutralizing force is required.
If the thread is tied to the tonearm
properly, there will be little effect upon
the tracking force with distance of the
arm from the center of the disc.
You will need to adjust the amount
of weight used and the distance of the
rod from the arm so that you can obtain the proper amount of counter -
2
force needed as the arm traverses various parts of the disc.
You can't use an ordinary disc to
determine the amount and direction of
the arm's motion. You will need a
smoother surface on which the stylus
can ride and be free to move. Further,
the surface must be of such a nature
that the stylus won't be damaged. I
suggest that you obtain a blank disc of
the type that recording studios use.
Such discs are mirror smooth.
The solution is not elegant, but it is
effective.
I believe that similar schemes are
used on commercial tonearms. However, the arrangement was taken from
a model developed by Mr. Robert Spei den of Rahway, N. J. He is an active
and skilled tape and disc recordist, well
known for his design of stereo cutting
heads.
FM Signal Strength Measurements
Q. For a small proportion of FM
listeners, there are instances where one
FM station provides all the music we
care to hear. I am in that category.
As a long-time reader of AUDIO, I
have read articles on FM antennas,
front -to -back ratios, antenna boosters,
antenna rotators, signal-to-noise ratio,
etc. All of these articles have given me
insight into the problems of receiving
an FM signal.
I believe one area has been constantly overlooked, viz., given a good antenna with a fine tuner, how can one
measure the signal strength in microvols of the incoming desired signal,
using some simple but sensitive measuring device? It would seem that being
able to measure the signal accurately
could at least serve as an excellent
means for orienting the antenna, certainly far better than the so-called
"magic eye" tube. It would be desirable
to know what the signal strength is before condemning the tuner to needless
investigation. Given the best orientation of the antenna, an adequate
knowledge of the signal strength would
also provide, among other things, the
appropriateness of the receiving location for a particular transmitted signal.-Name Withheld.
A. I would first say that knowing
the actual strength of a received signal
is not so important to antenna orientation as having a good indicator of relative signal strength. The input to the
first limiter is a good place to obtain
such information. Fairly sensitive indicator circuits can be easily designed
for this application. Various indicator
types are possible, but this is a subject
for an entirely different discussion.
Check No.
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-).
If your record player
f
today still has
a heavy turntable,
.
itmn.ust have yesterday's motor
Why din Garrarc switch
from heavy :urntables iwh:ch
Garrard pioneered cr automatics) to :he scienti ically
correct low mass turntable
.wv
featured cn the SL 95? Sitrnç.y because the synchronous
Garrard Synchro-Lab'" Motor has eLaiinated :he need for
heavy turntables, whichuere developed to compensa.e (by
impart_ng flywheel actipn) fcr the speed fluctua:io_ s inherent in induction motors. The light aluminum turntable
cr_ the SL 95, precision rratched to thee kinetic energy of
the Synchro-1,ab Motor. effectively relieves weight on the
renter bearing and redaces wear and rumble in this most
rritical area. And its ftl 11'72' d:arneter g:ves your records
Groper edge support.
The Synchro-Lab i/htar has also made variable speed
'controls as obsolete as :hey are burdensome to USE The
synchronous section of the motor eliminates the flurtua-
tioas in record rotation which
cause music 90 drift on and of
key. It guaran:ees completely
constant, unvarying speed regardless of voltage. warm ult
re ord load and other variables. By lochiag in to the faxed,
rigidly controlled 60 cycle current (rati er than varying
voltage), the synchronous motor insures unwavering rims:ca-_. pitch. And this brilliant new Garrand motor also incorporates an induction section that provides instant starring.
high driving torque and notable freedom from rumbles.
Garrard innovations such as the Synchro-Lab Motor
and new turntable are characteristic of tae achievement.
that make the SL 95, at $129.50. the most advanced re-_-cr:
Flaying unit available today.
For a Comparator Guide, describing all Garrarr
models, write Garrard, Dept. B2 -8A, Westbury, N.Y. 1E590
?í'(» 'il':;
Finest
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Of course, if you are attempting a
field study of a given location in terms
of its suitability for the reception of a
given station, you would, indeed, re-
This method will give you some idea
of relative signal strength and some
idea of the actual amount of signal
reaching the antenna terminals. Of
quire a calibrated source. That problem is not a simple one because you
would need some kind of standard signal strength upon which to calibrate
your equipment.
Probably the easiest thing to do is
to obtain a calibrated signal generator.
Connect a meter to the first limiter
grid of your tuner, or to the input circuit of the first limiter if it is a solidstate unit, and calibrate this meter in
terms of signal strength received at the
antenna terminals of the tuner with a
dipole antenna connected. The signal
generator would have to be made to
radiate some signal into the antenna.
You still won't have an absolute standard, though you will have an idea of
the linearity of your tuner's operation,
and you'll have some idea as to whether
or not a signal is weak or strong.
I think that considerably more accuracy will be obtained, and with less
likelihood of unwanted interference to
other nearby receivers, if you coupled
the generator right into the antenna
terminals loaded with its proper impedance, and the antenna disconnected. Now you can directly calibrate
the meter already described in terms of
input signal strength.
course, field measurements are often
made in terms of microvolts per meter
of antenna length and this would be
quite difficult for you to work out so
far as I can see right now.
One word should be said about the
meter connected to the first limiter.
Whatever circuit is employed to drive
the meter, it should not load down the
limiter. Improper operation of the
tuner will result. It is for the same reason we have high resistance in our
VTVM input circuits. You might find
it convenient to have several ranges for
this meter, similar to the operation of
a VTVM. I think you can improve the
accuracy of your readings this way.
Further, you can have a meter which
deflects further on any given range
than it would otherwise do. This will
enable you to see changes in signal
strength more easily.
The arrangement we have been discussing does not quite fulfill all of your
requirements. You had hoped that this
piece of equipment would indicate the
strength of the received signal so you
would know that tuner is working
right or not. If you make your tuner
double as a signal measuring device
and if the tuner breaks down, you have
Audio Techniques
other appliance unless it is a direct
part of the particular system.
I bought an eight -foot long, copper -
Reducing High Power -Line
Voltage
The line voltage here is, to my way
of thinking, much too high (128 V.)
Hence, motors and transformers run
too hot.
To alleviate this condition, I used an
old power transformer about 4 by 5
inches-first removing the old windings-to wind 60 turns of No. 12 Form var to make a swinging choke. I put
this choke in series with the line. This
gadget cut down the voltage from 128
V. to 115 V.
-
Now all motors and transformers
George R.
run cooler than before
Kirk, Stockton, Ill.
Reducing Hum
Many writers -in, it seems, have
severe hum problems.
Hum is no problem if a person attacks it in a straightforward manner,
using logic and not minding having to
run a stout lead each from turntable,
tape deck, tape recorder, tuner, amplifier, and preamplifier to a single, solid
ground which is not shared by any
clad steel rod, drove it into the ground,
and used some rocks until only a small
nubbin for the bronze clamp remained
above ground. Any gear which had a
three-wire grounded plug I lifted off
ground by using an adaptor socket
with the green wire and spade lug cut
off short. From each chassis I took out
to my ground stake a piece of no. 14
stranded wire for its own separate
ground lead.
These direct, simple, deliberate steps
have reduced hum to a state where the
tubes' "shot noise" is a mighty roar by
comparison. The ground is also cheap
by comparison with total system cost.
-Will Cochran, Hatfield, Pa.
Mounting Large
Electrolytic Capacitors
Editor's Note: This submission came
as a result of a discussion concerning
mounting of two 4500-12F 50-V electrolytic capacitors ("Audioclinic," Feb.
1968).
In my experience, the use of fibre or
rubber grommets to mount large electrolytic capacitors by their screws is a
risky and sloppy technique. A better
lost both the tuner and the "field
strength indicator." When the tuner is
repaired, you won't know if it is calibrated the way it was originally.
The strength of commercial stations
is fairly constant. Therefore, if you are
at your receiving location and there is
a degradation of the strength of the
received signal, the trouble is more
likely than not to be generated within
your tuner and not in the FM transmitter.
When you come down to it, if I
were to explore a potential receiving
site, I would use the tuner I expect to
use at that location. If it does not receive the station in which I am interested to my satisfaction, it really does
not matter very much what signal
strength you have available. This is
your tuner and it is the instrument you
will use.
Of course, if you knew the exact
signal strength at your proposed site,
and you knew your present tuner was
not adequate, you could select one
which would more likely do the chore
properly.
When I boil it all down, I would also
like to have a calibrated unit for the
purposes you have outlined, but it is
just too hard to make such a device
and know that it is as accurate as we
would both like. Therefore, I have discussed this matter from several angles.
technique to mount these 4500-p.F capacitors is to cut approximately 21/8"
holes in the chassis, through which the
2%4"-diameter, 4%4"-long capacitors are inserted. The capacitors are
then affixed by the use of proper
mounting clamps (that is, Mallory
George E. Mayer,
VR8 clamps)
Troy. N. Y.
.
-
Restoring Old Recording Blanks
I had a package of old Presto discs
that would not cut at all, even with a
hot stylus. I was able to salvage them
to a remarkable degree. I dipped them
in an acrylic retarder. The result was
that they were too soft to use for a
few days or weeks (I forget which) but
seemed to settle down and, while not
as good as new discs, work very well.
Also, by this same process I have
been able to re -use used discs (recorded microgroove), as the fine
grooves run together and a fairly good
surface results.
Unfortunately, I did not complete
my experiments, but just went far
enough to be encouraged. My process
was crude. I am waiting for the time
when I can dip them in a more dust free environment. John M. Kaar,
Menlo Park, California
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-.-
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What's New
In Audio
ventional FM receivers. The unit provides an accurate output from a fullscale indication of 1 L.1,V to 0.3 V, and
four ranges of deviation with full-scale
indications of 10, 25, 100, and 250 kHz.
Two internal modulation frequencies
are provided-400 and 1000 Hz-and
external modulation is acceptable to
accommodate stereo generators. Leakage is practically unmeasurable, and
modulation fidelity is flat within 1 dB
from 30 Hz to 100 kHz. Solid state
throughout, with minimal "warm-up"
time and high thermal stability, the
unit is suitable for production line use
where constant changing of output
level does not wear out the instrument
and change indications. Price, $695.00.
Check No. 10 on Reader Service Card
C/M Electronic Crossover
C/M Laboratories debuts its Model
601 electronic crossover, designed to
give the user any crossover frequency
from 100 Hz to 12.7 kHz in 100 -Hz
increments. A level control for relative
adjustment between high- and low-pass
amplifiers equalizes efficiencies of loudspeakers. The system is said to reduce
crossmodulation distortion between
high and low frequencies in a single
If you've been using any of the
so-called bargain tapes, chances
are you should have your heads
examined. The odds are good
that the heads are excessively
worn and you're not getting the
most out of your recorder. If you
want to keep a"factory-fresh"
sound to your recorder-and
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abandoned movie house in the Bronx,
MGM acquired Perspectasound and
Fine Sound and set up our operation
in elaborate studios at 711 Fifth Avenue in New York.
A Fifth Avenue studio was
a pretty far cry
chicken house in Stony Point. One
I remember vividly about that studio
at 711 was the fabulous aromas that used
to waft up the elevator shaft, since the
kitchen of the famous "Le Pavillon" restaurant was on the ground floor. If I remember, you did some pretty big pictures
in the Perspectasound process at 711.
FINE: I guess the best of them was the
from
thing
M2hSä
BERT WHYTE
The Professional
Viewpoint
a
Marlon Brando "Julius Caesar."
A dialogue with Bob Fine, colorful and controversial head of Fine
Recording, New York City
In the heart of the "silk-stocking"
district of New York City, across the
street from proud Steinway Hall and
surrounded by the chic boutiques and
swank shops that cater to the "beautiful people," stands the Great Northern
Hotel. It is old and begrimed, and gives
off an aura of genteel shabbiness. In
this unlikely locale, the modern studios
of Fine Recording occupy some 38,000
sq. ft. of space. A special elevator took
me directly to the reception area on the
penthouse floor, which is part of the
Fine Recording complex, and shortly
thereafter I was escorted into the panelled office of Bob Fine, president of
Fine Recording. Here the results of our
talk:
Bob, you've been in the recording business since you were a boy of fourteen, am
I right?
FINE: Yes, in 1938 I worked for Miller
Film in Steinway Hall as a general
flunky and as a "wax shaver." In those
days we were still doing direct mastering on cakes of wax, and my job was to
prepare them for recording.
that the same Miller whose cutter you
used years later when you were recording
the Mercury "Olympian" classical recordIs
ings?
FINE:
That's right. You may remem-
ber how appalled recording people were
because Miller wanted a thousand dollars for the cutter. What a change from
these days, when a Westrex stereo
cutter runs more than four thousand
dollars!
believe your first studio venture was in
1951, after you had left Reeves Sound.
York. Most of the equipment was in a
converted chicken house and the disc cutting operation was in a former barn.
A lot of the recording people resented
having to make the trek "up the mountain," but we prospered after a fashion.
It was while you were located at Stony
Point that you contracted to do the new
Mercury classical series, which gave birth
to your recording truck. Wasn't it about
this time that you invented Perspecta-
sound?
FINE: Well, you may recall that the
movie industry had been taking an awful licking from television, and they
were desperately searching for ideas
and gimmicks to stem the TV tide.
Thus we had the rash of three-dimensional movies and finally Cinemascope,
which with the wide-screen aspect ratio, virtually demanded stereophonic
sound. The trouble was that true stereo
was almost impossible to incorporate
into a movie because of the constantly
changing perspective. In the long run,
it really came down to was that the
most practical thing was an emphasis
on lateral directionality because of the
wide screen. I figured the way to do
this was by post mixing after the picture was finished. By means of panning
pots and pilot signals to activate left,
center and right loudspeakers behind
the Cinemascope screen, with deliberate "built-in" directional sound, we
could lick the perspective problems.
Perspectasound, then, was directional
sound on an optical track, which was
compatible with standard film reproduction, so all that was necessary was
to make one negative. In theatres
equipped with the Perspectasound circuitry and three speakers, a quasi stereo effect was obtained.
I
FINE: Right. I was quite happy at
Reeves, but I always had a yen to have
my own studio and thus Fine Sound
came into being in Stony Point, New
I take it that this is when Loew's/MGM
showed interest in Perspectasound?
FINE: Actually we had shown the idea
to several film companies, but after a
demonstration of the system in an
understand that you became emeshed
I
in some sort of patent fight and unfortunate legal problems, which resulted in the
ultimate demise of Fine Studio.
FINE: All too true. I never received a
nickel on my patents, even though
Perspectasound is still used in some
foreign theatres. In any case I wanted
to start another studio, so to raise
money I went to Europe and designed
studios. This was just about the beginning of stereophonic recording in Europe in 1956, and I did two in Paris,
one on Milan, and several others. I had
my lawyer looking for possible studio
locations in New York, with the proviso that it should have a ballroom.
Shortly afterwards he came up with
the ballroom of the Great Northern
Hotel; we signed a lease giving us exclusive use of the ballroom and, thus,
Fine Recording was born.
Speaking of leases, how secure is your
present lease in view of the fact that you
are in an old building, with the present
tendency to tear down the old and build
still another glass and aluminum skyscraper?
FINE: We have leases running to 1980,
and the plot of land the hotel occupies
is not in itself big enough to build on.
Someone would have to put together
a large expensive parcel of land, in addition to the hotel plot, to make a new
building a practical proposition.
assume this is why you are going ahead
with your present expansion plans?
FINE: Yes, we now have 38,000 sq. ft. in
I
this building. We occupy the total top
of the hotel where we have two mixing
theatres, all the disc cutting operations,
production offices, and main reception
area. On the twelfth floor we occupy
50 per cent of the space, consisting of
an office wing, another studio wing, the
automated mastering section, the electronic music operation (the Moog
synthesizer is here) and a research
wing where we carry on research in
AUDIO
8
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NOVEMBER 1968
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800 cycles upward. Below 800 cycles,
reverb just isn't significant.
In addition to the ballroom which is your
Studio A, I notice a Studio B just off the
hotel lobby. Would you describe it?
FINE: Studio B used to be the serving
kitchen for the ballroom. We cut it off
from the ballroom and put in an isolation wall which weighs several tons,
but which is in a "floating" mode to
avoid sound transmission. Studio B is
fairly small, but with a high ceiling.
We use it a lot for voice recording and
for rock-and-roll dates and orchestras.
We think it has a good sound, but it is
a contrived studio, whereas Studio A
has its own completely natural sound.
Fig. 1-Recording sessions in Fine Recording's Studio "A"-the ballroom.
audio and in other electronic but unrelated areas. The lobby of the hotel is
where the main studios are located. And
our tape duplication plant is in the
basement area. When we took over the
ballroom, which is now our Studio A,
it was a dirty mess, painted a garish
red. It had an old oaken stage where
the N.Y. Philharmonic used to rehearse. The chandeliers were broken,
the wooden panelling largely destroyed.
Two years later we restored the ballroom to its former glory, replete with
virginal white paint and gilt, as well as
new chandeliers.
What changes did you make to turn it into
a recording studio? I understand there
were large columns in the room which
some people criticized for breaking up
working space.
FINE: We have had some complaints.
Nevertheless we have been able to accommodate 60- to 70 -man orchestras
for symphonic recordings and motion
picture scores with a minimum of difficulties. We built a control room endeavoring not to change the acoustics
of the room. The huge old oaken stage
was removed and replaced with a
smaller stage which we use when it is
necessary to elevate an orchestra. As
far as I am concerned, the acoustics
make up for the small inconveniences.
complishments, I've disagreed with him
on this standard of reverb measurement which is calculated on the basis
of how long it takes from the initiation
of a sound until it measures 60 dB
down. I think this is quite wrong ..
you do not sense reverb past the point
where the sound is down 15 dB. You
just don't sense it, or hear it, or feel it.
.
Then you feel that according to your system of measurement the ballroom has suitable acoustics. Measurements aside, don't
you feel that the real burden of proof is
how your recordings actually sound?
FINE: That's true, but just for the record I think we have slightly over a
second of usable reverb. Of course there
is still the matter of the frequency
spectrum in the room. At what frequencies does the room reverberate?
Some rooms have huge peaks at say
400 cycles [sic] or standing waves
which by oscillatory reinforcement can
make a room appear to have more re verb. I am considering that you must
take the frequency spectrum into the
reverb picture and measure from about
Getting back to the ballroom, when you
do "pop" dates there, do you use the
natural reverb or do you augment with
reverb chambers?
FINE: We use EMT's reverb chambers
because, with the sound preferred in
today's pop market, with ears attuned
for exaggerated reverb, it is too difficult
to use natural reverb. Then, too, if you
have a singer in a live room, close to a
where you want isolamicrophone
tion
you eliminate so much of the
natural reverb you must make up for
it with EMT's. Unfortunately, when
you are recording rock and roll and all
these wild, screaming, brassy things .. .
a live studio is extremely difficult to
handle. For rock and roll the most successful approach seems to be these lowceilinged, very -dead studios, where they
don't really do conventional mixing and
can control the sound quite readily. I
like the sound of a big wild orchestra
in a live room, but it is difficult to mix
and achieve instrumental isolation.
However, when you talk of isolation in
stereophony, the acoustical coupling is
important and many people really
don't like that.
...
...
understand you have recently installed
recorders in the ballroom and that
this solves acoustic problems to a certain
extent.
FINE: Since we have installed the 8I
8 -track
2-Chief Engineer Ted Gosman at controls of the console used for Studio "A"
Fig.
sessions.
What is the reverberation time of the ballroom?
FINE: That is an interesting point.
Measured by the Academy standard
reverb scale, the reverb time is about
three seconds.
track Ampex and will soon be installing 12 -track Scully recorders, the ballroom has sort of been "rejuvenated"
for pop recording. You see, we no
longer record in the classic sense of the
word. Now we lay down against an
electronic click track [A click track is
like an electronic metronome with beats
down to a 32nd note, but 1/8ths notes
the rhythm on
are usually used]
the drums,
say two or four tracks
bass and guitar, and any other rhythm
instrument, and we record a basic
rhythm track on the machine. Everyno one
one works with earphones
...
Isn't that fairly long for recordings?
FINE: Yes, but I don't believe in that
reverberation measurement. In the
number of times I've spoken to Leo
Beranek, and with all due respect to
that learned gentleman and his ac-
...
...
10
AUDIO
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11
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...
works live anymore
everything is
recorded against these electronic metronomes. We may put out 30 to 40
earphones on a big date ... one for each
musician. As I said, we make a rhythm
recording on 2 to 4 tracks of the eight track machine, put the machine into
"sel -sync" operation [sel -sync (selective synchronization) works this way:
what has previously been recorded is
played back on the record head . . .
the record head becomes a playback
head
and a 4th head records the
new material or new track in synchronism with the previously recorded
sound. It is really just an elaborate
head switching system. After each track
is recorded, you rewind to the start and
you are ready to add another track or
tracks, as the case may be. As you can
see, the possibilities are limited only by
the number of tracks available.] If
there is a woodwind section we sel-sync
record them on another track or tracks,
as required. The woodwind instrumen-
...
talists hear the rhythm tracks through
their earphones and play against the
rhythm. Next we sel -sync the brass on
one or more tracks in the same fashion
as the woodwinds. If there are voices
they are usually recorded sel -sync on
tracks 7 and .8. The voices are recorded
singing the same material on the two
tracks, but at different times. They sing
the same harmonies, etc., but when you
mix the tracks together, because their
timing is not that precise due to the
human element, you get this bigger
sound which enables voices to compete
acoustically against the huge sounds of
brass and rhythm.
Bob, with so many tracks being used for
the various elements in a recording, I can
see now why you are installing 12 -track
machines and would probably like to put
in that monster 24 -channel Ampex which
uses tape two inches in width, if you could
afford it.
FINE: Well, I think it tends to get ridiculous after a certain point. You
could put practically every instrument
on its own track with the 24 -channel
unit ... and in certain of these wonderfully complex rock-and-roll recordings
recording sounds
they do just that
that are humanly impossible to produce on a standard recording basis.
...
Once all 8 tracks are recorded, what is
your next step?
FINE: We go into a re -mix situation
where we literally re-create the session
from the stored information. That can
go on for hours and hours ... which for
a studio is economically very nice .. .
it's a new thing which never was done
in studios before. It is a new market
because, after all, in the recent past you
mixed a date and, outside of a few balance adjustments, that was that; there
was no further processing. Now you
have 8 or 12 separate sources of information and it's a whole new world of
recording that can be either abused or
used constructively.
presume that, once you mix all the
tracks, it is brought down to a two -channel stereo recording for the ultimate consumer product, be it disc or tape in its
I
various formats.
FINE: You know it all used to be mixed
right down to monophonic, but with the
demise of mono recordings, we do two channel stereo, unless it is for a foreign
market where mono still is predominant.
amount of electrical energy to deal
with. With a normal type of compression system you can hear the "gating."
Just jangle a key ring or put maraccas
in front of a mike with the compressors
on and listen to what you have at the
output. In cases of very efficient modern compressors, you don't hear the
keys or the maraccas unless they are
down below the thresholding levels of
these instruments. Put a piano through
this kind of compression and you can
turn a piano into an organ!
Do you ever use limiting or compression
on classical material?
FINE: We do have to in some cases of
extreme dynamic range, which we have
done for years. We do have to use manual monitoring; this is always done
with A&R people
not with engineers. There are real-time situations
where you cannot possibly involve
yourself with the dynamic range you
have on the tape
it is usually impossible to put it on a record. If you
make a record with too wide a dynamic
range, people can't listen to it ... or
don't want to be bothered with the constant adjustment of controls. We can
record a wider dynamic range than we
do on any medium that we make
but every time we have fought this battle that people should listen at the right
level for the proper dynamics, we lost
the battle. We therefore temper the dynamic range to within usable levels below normal room levels. Our original
Mercury classical recordings had so
much dynamic range we used to get
complaints from the field that people
would lose whole sections of pianissimo
music when they adjusted the fortes to
the low listening levels prevalent in
most apartments and in many homes.
.
suppose the A&R producer
is the one who decides where the various
tracks should be placed in terms of left/
right stereo orientation.
At this stage,
I
FINE: Yes, and he may also decide to
...
all of our con"pan" some tracks
soles are equipped with panning pots
he may want an effect like a marching drum. What the producer may desire may be so complex as to require
another 8 -track mix from the original
8 -track recording.
.
Returning to the ballroom, Bob, I take it
that a recording in the classic three -channel stereo "symphonic style," with the
traditional instrumental positioning, is
quite rare these days?
Certain people still like the
"pure" 3 -channel approach, and we do
FINE:
some occasionally. Nowadays most
producers are of the type where 50 men
can be playing and they want to hear
an electric harpsichord isolated, and at
a louder level than the group. It is
incongruous, but it is typical of today
and is at least legitimate in terms of
an interesting sound, if nothing else.
What are your feelings about the use of
compressors or limiters?
FINE: When you put any limiting
equipment that is of a type where you
rectify the output of an amplifier and
appply it back to change the gain of
the input stage of the amplifier, you are
seriously affecting pulse information.
That is one of the reasons that 8 or 9
years ago we changed our whole compression system. We do not use an RC type compression system. Our compressions systems are based on the factor
that the long-wave information is redundant and is consuming the greatest
power. Our compressors pass pulses
and act on long -wave information. The
result is great presence on a record or
a film without having a tremendous
.
.
...
.
www.americanradiohistory.com
AmericanRadioHistory.Com
.
Are you still interested in film work?
FINE: Most assuredly. We have two
theatres on the top floor where we do
motion picture mixing. This is in our
Studio C.
Do you use 35mm magnetic film in the
scoring studios?
FINE: We use both tape and film, and
can go from one medium to the other
merely by switching.
Are your consoles of solid-state design?
FINE: We are in the process of install-
ing solid-state consoles in all the studios. At the moment, the consoles are
tube jobs with the exception of a new
solid-state unit in Studio D. The console in the ballroom has a turret that
controls reverb. I mention this because
we used to have concrete reverb chambers in the basement, which at one
time were food storage lockers. They
(Continued on page 100)
AUDIO
12
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NOVEMBER 1968
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AUDIO
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13
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Tape Guide
HERMAN BURSTEIN
If you have a problem or question on
tape recording write to Mr. Herman
Burstein at AUDIO, 134 North Thirteenth Street, Philadelphia, Pa.19107.
Please enclose a stamped, selfaddressed envelope. All letters are
answered.
Going Professional
Q. I haue decided to turn my tape
recording hobby into a business, but I
am confused by what type of equipment I might buy. I am going to use
12 microphones, with cable runs of 25
to 45 feet to the control room. I would
like to haue separate bass and treble
controls for each mike input, and I
would like to use a tape recorder with
built-in écho at 7.5 and 15 ips. I would
welcome your advice.-Jerald G. Boy Kin, Mailey, No. Carolina.
A. I do not recommend the use of
a tape recorder's built-in echo facility
for professional or semi-professional
purposes. Such "echo," which consists
simply of feeding some of the playback
signal into the record head, is only a
rough approximation of the effect produced by professional echo devices.
Your desire for as many as 12 mike
inputs, together with separate bass and
treble controls for each, suggests that
you may have to go into a custom-built
mixer (made for you or by you). A
desirable first step is to find out what
is commercially available, which you
can do by perusing the catalogs of mail
order houses and by writing directly to
manufacturers of professional mixing
equipment. You may also want to look
at the articles on mixers that appeared
in the October 1962 and October 1963
issues of
AUDIO.
Intermittent Noise
Q. I have an intermittent noise in the
playback preamp of my tape recorder,
sounding like a heavy scratch in a record at relatively regular intervals. It
seems to be in both channels and comes
and goes. Sometimes it will start when
the preamp is first turned on, and later
it will disappear; or it may not be pres-
ent at first and may appear after a
half hour or hour's use. I have tried
replacing transistors in the playback
preamp, but without improvement. I
will appreciate any thoughts you may
have.-Lewis J. Thomas, Philadelphia,
Pa.
A. There may be inadequate de coupling in your power supply, possibly because of a defective filter capacitor, which leads to oscillation that you
hear in the form of a periodic "heavy
scratch." If replacing the filter capacitors) does not help, investigate other
components in the power supply.
Tape Comparisons?
Q. Has any one ever compared the
quality of various tapes? It is hard to
tell which is best for a given applicaThomas Higgins, Alexandria,
tion?
Va.
-
A. To my knowledge, no one has
made an authoritative brand -by -brand,
type -by -type comparison of tapes, at
least for publication. The best approach
still seems to be to try several brands
and types made by reputable companies and find out empirically which
is best suited to your particular tape
machine and needs.
Adjustment of Bias
Q. In the instruction manual for my
tape deck, regarding adjustment of recording bias, it mentions to record a
1000 -Hz tone, adjust the bias control
for peak bias, and then back off on the
control 1/2 dB. This puts the tape deck
in an under -biased condition. Publications that I have read on the subject
state that many professional tape
decks are adjusted for peak bias, while
others are adjusted for a 2 -dB over bias. They state that under-bias causes
distortion, while over -bias cuts down
high -frequency response.
The manufacturer of my tape deck
claims fantastic treble response at 3.75
ips. I attribute this to under -biasing.
Am I correct? When I adjusted my tape
deck for peak bias with a 400-Hz tone,
I found that the 3.75-ips high -end response dropped from 15 kHz to 10 kHz.
At 7.5 ips the response dropped from
19 to 15 kHz. How should bias on my
machine be adjusted?-Don Woodruff,
San Rafael, Calif.
A. Under -biasing will extend treble
response, at the price of increased distortion. To elevate their claims as to
treble response, some manufacturers
resort to under -biasing.
The method of biasing tends to differ
somewhat among manufacturers, de-
14
pending upon their philosophy of treble
response versus distortion, upon the
kind of tape they envision to be used
with their machines, upon design characteristics of the machines and heads,
and upon considerations of signal-tonoise ratio.
To the extent there is a widespread
practice, and one that usually produces
close -to -optimum results, it is this: at
7.5 ips a signal of 1000 Hz (some manufacturers recommend 500 Hz) is recorded, and bias is adjusted until maximum signal is obtained in playback;
bias is then further increased until output in playback is 1/2 dB below maximum output. Such over-biasing tends
to put the tape in a region of response versus -bias that is relatively flat, so that
the tape is not too sensitive to moderate
variations in bias that may occur as
the machine warms up, as line voltage
changes, etc. Usually it does not matter
too much whether the signal is 500 or
1000 Hz at 7.5 ips; for both frequencies at this speed (i.e. for the wavelengths in question) the curve of output versus bias is very similar in the
region of maximum output.
For a machine seeking a desirable
balance among good treble response,
low distortion, and low noise, response
to about 15,000-18,000 Hz at 7.5 ips
and to about 10,000-12,000 Hz at 3.75
ips (down no more than about 2 dB)
is pretty much in line with the present
state of the art. To an extent, the upper
frequency limit depends upon the quality of the tape heads, particularly the
playback head.
Automatic Gain Control
Q. I am doing tape recordings of
weddings. The officiating Priest, Minister, etc., usually has a tremendous
voice, and he generally pins the VU
meter. The groom and the bride as a
rule speak subduedly, and all three
stand in a tight circle. Set the tape recorder for Minister, and I don't get the
bride and groom; set the tape recorder
for the bride and groom, and the Minister pins the VU meter but good. What
can I use to electronically equalize the
gain?-Andrew R. Winkler, Newark,
New Jersey.
A. Some of the inexpensive tape recorders have an automatic -gain -control
circuit. If such a machine isn't suitable
for your needs, you might obtain a
schematic of the machine and copy
that part of the circuit involving automatic gain control. Another possible
approach is to use a microphone with
a "figure 8" response characteristic (a
ribbon microphone) and aim it so that
the relatively dead side points most
nearly at the Minister.
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Four Heads. The 770-2 has
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also incorporates automatic built-in
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Sony Model 770. Priced at $750. For
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Letters
SCA Receivers
I have just read with interest the
article by Mr. Leonard Feldman concerning SCA-Private Music Channels
on FM Stereo.
I am wondering why he did not advise his readers that use of an SCA
Channel by unauthorized parties is a
federal offense, and subject to a sizable
fine and violates section 605 of Federal
Communications Act.
JOSEPH F. HARDs,
Seeburg Music Library, Inc.
Chicago, Ill.
Ln
o
Ln
V
Use of an SCA receiver is unauthorized for commercial applications, but
there are no restrictions for personal,
non-commercial uses. This was noted
in an article that followed in the next
issue of AUDIO, October 1968.
Ed.
I read your excellent article on SCA
in the September 1968 issue of AUDIO.
I had built a [SCA] receiver for use
at home but have never been able to
FREE
SEND TODAY
completely separate the main channel
audio from the SCA music. At normal
listening levels it can be barely heard,
but it is there.
Recently I reviewed the fundamentals of the transmission spectrum
transmitted and wonder if I have hit
on the reason. In your diagram of the
spectral distribution of information on
an FM channel you show the L -R side band as ending at 53 kHz. However,
I am wondering if the maximum deviation of the 53 kHz due to the 75%
excursion possible due to amplitude of
15 kHz would send that limit out to
67.5 kHz. If this is the case, the maximum separation possible to achieve,
regardless of the selectivity of the circuitry employed, would be limited to
less than 40 dB. This would mean that
the main channel could be heard in a
quiet room with normal listening level
of the SCA music.
Am I right or do I misunderstand?
SALVATORE A. ROMANO
f
z
CC
o
o
Q
_
V
Brooklyn, N. Y.
Author's Reply:
I have run into much the same problem with respect to cross -talk from
main channel into sub -channel, but
suspect the cause lies in several other
areas than the one you mentioned. For
one thing, the stereo sub -carrier information is AM sidebands about a center of 38 kHz, and even though the
carrier frequency itself is suppressed
before transmission, the sidebands, resulting from what started out as an
audio -modulated sub -carrier, can only
be two in number: one above and one
below 38 kHz by an amount equal to
the frequency of the modulating tone
or note. Thus, even when 15 -kHz audio
is being impressed upon the L -R channel, sidebands created will be at 23 kHz
(lower sideband) and 53 kHz (upper
sideband) only.
The two primary reasons for crosstalk that I have discovered relate more
to equipment than to spectrum distribution. For one thing, any main channel tuner non-linearities (as for example, in the main channel i.f. strip
of the detector circuitry) will cause
varying degrees of cross -modulation
between main and sub -channels. Remember, too, that main channel demodulated voltages are about ten times
as great as the amplitude of the 67 kHz sub -carrier which you are trying
to work with. Thus, the problem of
filtering out main channel is 20 dB
greater than if there were a one-to-one
relationship.
The SCA decoder which I described
in the following issue of AUDIO (October 1968) has an inherent rejection
capability (with respect to the main
channel) of better than 55 dB, yet, with
every tuner with which we've tried it,
some deterioration takes place. We did,
however, get as high as 50 -dB rejection using a good -quality, well -aligned
tuner. Incidentally, even the "commercial" units used in restaurants and the
like seldom do better than this, but
the level is kept low so that the crosstalk is all but inaudible.
We have noted, too, that some stations come through with more of this
cross -talk than others, which leads us
to believe that station equipment is at
fault to some degree, as well. The FCC
does not care about setting limits of
cross -talk from main channel to sub
channel at the transmitter (since SCA
service is not "public programming"),
but does set strict limits on SCA crosstalk into main or stereo channels. One
of the reasons that SCA operators turn
off the sub-carrier during pauses between music is to get around this small
amount of cross -talk, which is masked
when music is playing on the sub channel but would be more obvious
during periods of silence.
-
LEONARD FELDMAN
Great Neck, L. I., N. Y.
(Continued on page 98)
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AUDIO
16
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NOVEMBER 1968
-t
A Marantz
speaker system
is the finest
money can buy.
(Our competitors know about this ad.)
Marantz has always set the standards others follow. In
preamplifiers. Amplifiers. Turntables. Tuners. And
stereophonic receivers.
Today, Marantz once again expands its reputation for
audiophonic excellence with the introduction of
a new concept in speaker systems.
After years of experimentation, Marantz' first
two Imperial Speaker Systems are now ready to
be enjoyed by discriminating connoisseurs.
Technically, both feature a three-way design
incorporating five speakers. There is a 12" Quad linear woofer which crosses over at 700 Hz to two
mid -range drivers, then crosses over again at
6,000 Hz to two high frequency reproducers.
The sleek, contemporary Imperial I has a smart, walnut
cabinet with a hand -rubbed French lacquer finish aid is
priced at $299.00. The elegant Imperial II, hand-crafted
from selected hardwoods and finished in distressed
antique, features a stunning hand -carved wood
grille. It's yours for $369.30. Both possess
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Designed to be number one in performance... not sales.
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AUDIO
NOVEMBER
97f>ß
CO., INC., 1968. MARANTE IS A SUDSIDIARY OF SIJPERSCOPE, INC. P.O. ©OX
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a
beauty of cabinetry equalled only by the beauty
of their sound.
When you hear, when you see these magnificent speakers, only then can you fully appreciate
what goes into making a Marantz a Marantz. Your
local franchised Marantz dealer will be pleased
to furnish you with complete details and a demonstration. Then let your ears make up your mind.
SUN VALLEY, CALIFORNIA 91352
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17
a similar hi-fi show in the spring of '67, as AUDIO
readers and many Delaware Valley residents will
recall. As in the earlier show, component equipment will be sold at the show!
EDITOR'S
REVIEW
Hi-Fi Show Biz
The 19th IHF-sponsored New York High Fidelity Music Show held in September was a rousing
success, according to reports. The IHF advised
that public attendance came close to matching last
year's 22,500. Just as important, we got the impression that the show -goers were an enthusiastic
group who really enjoyed themselves. We were disappointed, however, in the Statler Hilton Hotel's
services for the show. Ventilation was very poor,
for example, and elevator service was frustratingly
slow. Fortunately, spirits were not appreciably
dampened. Another unhappy surprise was the
poor attendance at the show's free, and heretofore
very popular hi-fi seminars. Perhaps the sweltering
atmosphere and poor elevator service (seminars
were held 14 floors above the exhibit area) were
responsible. Also, most show-goers simply forgot
about the seminars as they darted from exhibit to
exhibit.
West Coasters will also have an opportunity, by
the way, to enjoy high-fidelity seminars. The seminars will be featured at the San Francisco show,
October 31 to November 3. An interesting innovation at the upcoming San Francisco Show will be a
Bonus Savings Certificate to all Show visitors that
allows them a saving on component equipment
purchases of at least $200. (Fair-traded merchandise or products with special franchise limitations
will be excluded.)
Another hi-fi component show-a European one
-was presented in September: The "Hi-Fi 68
Dusseldorf." This first hi-fi exhibition in Federal
Germany had 124 exhibitors from 12 countries.
An official report indicates that 32,000 tickets
were sold. The West German show also featured
hi-fi talks by experts, as well as musical performances. We understand, too, that exhibit rooms
were sound proofed.
Philadelphia will be the scene of a hi-fi component show, February 7-9, at the Benjamin
Franklin Hotel. The show will be presented by
Almo Radio Co., Inc., with many hi-fi equipment
manufacturers participating in it. Almo presented
18
Sound Talk
The 3M Company has revived its quarterly
"Sound Talk" bulletins, the first of which has already been published. If the five -page bulletin on
magnetic tape is any indication of what is to follow, it should easily equal popularity of the company's earlier bulletins. Readers can obtain these
bulletins FREE by writing to the 3M Company,
Magnetic Products Div., Marketing Services Department, 3M Center, St. Paul, Minn. 55101.
"We Try Harder"
Avis -Rent-A-Car has a
new version of the "We
Try Harder" theme in its
well-known button. It's a
reproduction of each word
as it appears visually on
an oscilloscope's cathode
ray tube (obtained by
speaking the words into
a microphone).
Electronic Music
New Yorkers and Bostonians can listen to
electronic music by Jean Eichelberger Ivey on
WNDT-TV (Channel 13, New York) weekdays
at 8:55 A.M. and in station breaks scattered
through the day. The music, called "Continuous
Form," plays on a continuous -loop tape cartridge;
excerpts are selected at random, each accompanied
by films by Wayne Sourbeer in a random association. The Psyche Sound and Sight is also being
used a few nights each week by WGBH-TV
(Channel 2, Boston) .
The New York Audio Engineering Society Convention and Exhibit, celebrating the AES's 20th
anniversary October 21 to 24, has a complete technical session on developments in electronic music
systems, with five technical papers on the subject
being presented. And it is reported that the new
West Coast hi-fi seminars at the San Francisco
High Fidelity Music Show will feature, among
others, Robert Moog, who will give a demonstration -lecture on electronic music.
Judging from the great activity in this field, as
noted above, and with recordings for LP discs and
broadcast commercials making wide use of electronic music, interest in this "music" form is not
A.P.S.
limited to "under -30" listeners.
AUDIO
NOVEMBER 1968
Invitation to euphoria.
Among all those who
listen to music from
records, there is a select
few who do it very,
very seriously. They
originally spent countless hours comparing
one component against
another. Then they tried
their speakers here and
there at home until they
worked to perfection
with the room.
And when people like
this listen, they do
nothing but listen. Just
as though they had paid
good money for dinner
out, orchestra seats and
a baby sitter.
They know what that
record should sound
like. From deep soul satisfying bass to those
delicate, sweet highs.
They're never satisfied
until they find themselves in that blissful
state that tells them
there's just nowhere
else to go.
Euphoria.
If you don't know it,
just leave everything
as it is. Except your
cartridge and favorite
record. Take both to an
audio dealer who has
a particularly good
listening room.
Listen first with your
present cartridge.
Then with the golden
XV 15/750E. That's all.
You won't mind spending the sixty dollars.
It's the least expensive
passage to euphoria
you'll ever find.
Pickering & Co.,
Plainview,L.I.,N.Y.
THE XV -151750E, WITH A DYNAMIC COUPLING FACTOR. O' i92. DELIVERS 100.1 MLSIC POWER THWOEIG-$OUT THE ENTIRE
AUDIBLE RANGE AT 1/2 TO 1 GRAM TRACKING FORCE. IT IS THE NEWEST AND FINEST OF PICKERING'S XV -15 SERIES.
EACH XV -15 MODEL IS DCF-RATED FOR A SPECIFIC CALIBER OF TONEARM, FROM A DCF OF 200 TO 750, AND ALL DELIVER
100: MUSIC POWER. PRICED FROM $29.95. DYNAMIC COUPLING FACTOR AND DCF ARE SERVICE MARKS OF PICKERING & CO.
AUDIO
NOVEMBER 1968
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19
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20
AUDIO
NOVEMBER 1968
Altec AcoustaVoicing*
DON DAVIS
Part
1
How the acoustic characteristics of a room can be compensated by a
new method of applying properly designed filters in the sound system
EQUALIZATION OF SOUND SYSTEMS to compensate for the
detrimental interaction that
can occur between the sound system and the acoustic environment
(auditorium, arena, etc.) where it is
installed has been under serious investigation by physicists, engineers,
and experimenters for a number of
years. (See Footnotes 1, 2, 3, 4, 5,
6, and 7.) These investigations determined that the acoustic environment affected the amplitude -frequency response of loudspeakers, as
shown in Fig. 1.
William B. Snow, a gifted scientist, showed that a sound reinforcement system near its regenerative
state ( just below acoustic feedback)
could and did increase the decay
time of certain highly reverberant
frequencies.8 Finally, Richard V.
Waterhouse of The American University, Washington, D. C., applied
the classic Nyquist criteria to discuss the conditions necessary to
achieve regeneration in a sound reinforcement system.9.10.11 With these
major breakthroughs and the accumulated experience of hundreds of
skilled but anonymous workers in
the professional sound field, the
stage was set for the realization of
detailed sound system equalization.
tude/frequency response to the
acoustic environment where it is
installed and used.
While the words "Acousta-Voicing" and its derivatives are more
than likely due the same eventual
obscurantism that finally engulfed
the words "high fidelity" and "stereophonic," this two-part series will
describe what they mean today while
they are still pioneer-pure.
The descriptive term AcoustaVoice* stems from the time-honored
practice of voicing or regulating a
Altec Acousta-Voicing
Acousta-Voicing is a total programmed approach to the application of these discoveries to the
design, installation, testing, and adjustment of a sound system's ampli-
pipe organ to fit the acoustic environment in which it is installed.
Therefore, an Acousta-Voiced sound
system is one that has been "voiced"
or regulated to fit its acoustic environment. In practice, AcoustaVoicing views the system design jn
terms of the maximum results that
theory will allow, designing up to,
but not beyond, that point. It further
sets up procedures and tests to ensure the ability of the electronic portion of the system to support the
acoustic requirements. Finally, it
regulates the amplitude frequency
response of the total electro-acoustic
system, including electronics, transducers, and the room itself to the
overall response that allows the
greatest tonal quality and acoustic
gain.
Acousta-Voicing removes no usable program material, but, rather,
brings into equality with the majority of frequencies those special frequencies that the room and sound
system together actually over -em-
"T.M. LTV Ling Altec Inc.
Harry Kimball, "Attenuation Equalizers," Motion Picture Sound Engineering, D. Van
Nostrand Co., Inc. New York 1938. Pages
228-272.
º Arthur C. Davis, "Steps to Improve TV Audio," Video Engineering, March 1950.
s Ercel Harrison, "Hi Q Equaliztion
Reactors,"
Altec Lansing Bulletin AL 1164, 1958. Page 11.
* Wayne Rudmose, "Equalization of Sound Systems," Noise Control 4, No. 24, July 1948.
s C. P. Boner and C. R. Boner, "Minimizing
Feedback in Sound Systems and Room Ring
Modes with Passive Networks, J. Acous. Soc.
Am., 37, 131, 1965.
° William K. Connor, "Theoretical and Practical Considerations in the Equalization of
Sound Systems," J.A.E.S. Vol. 15, No. 2,
pages 194-198, April 1967.
7 Don
Davis, "Adjustable 1,¢ Octave Band
'Notch' Equalizer for Minimizing Detrimental
Interaction Between a Sound System and Its
Acoustical Environment," paper given at the
102nd SMPTE Technical Conference, Sept.
AUDIO
NOVEMBER 1968
phasize. (See Figs. 2A and 2B.)
Through the use of a detailed technique and precision test equipment,
these adjustments can be made with
speed (as little as two hours) and
accuracy. The audible results are
high acoustic gain, wide and uniform
acoustical frequency response, and
remarkable freedom from reverberant coloration.
As might be expected, AcoustaVoicing is not for the beginner. The
successful Acousta-Voicer must understand the basic design problems
of sound reinforcement systems and
how to solve them. This first article
will discuss the requirements for
good hearing in a space, the role of
the sound reinforcement system, the
nature of acoustic feedback, reverberant coloration, and the basic design criteria for Acousta-Voicing.
Requirements for Good Hearing in
Traditionally, four
basic factors are considered to determine how satisfactory the listening conditions in an auditorium will
be. These four factors are:
Auditoriums.
Quietness of the auditorium.
Useful loudness of the program
material.
3. Evenness of distribution of program material to all areas in the auditorium where there are listeners.
4. Avoidance of excessive decay time
or delay time in the reception of the
direct and reflected sound combined at
the listener's ears. ("The successive
sound in rapidly moving articulation,
either of speech or music, is clear and
1.
2.
22, 1967.
William B. Snow, "Frequency Characteristics
of a Sound Reinforcement System," Journal
of the Audio Engineering Society, Vol. 3, #2,
April 1955, pages 74-76.
° Richard V. Waterhouse, "Theory of Howl back in Reverberant Rooms," Journal Acoustical Society of America 37, 921, May 1965.
1° H. Nyquist, "Regeneration Theory," Bell System Technical Journal, 11, 126-147, 1932.
11 H. W.
Bode, "Network Analysis and Feedback Amplifier Design," D. Van Nostrand Co.,
s
Inc. New York 1959.
21
www.americanradiohistory.com
AmericanRadioHistory.Com
2
100
3
4
5
6
7
9
8
10
11
12
14
13
15
16
17
18
19
20
21
22
23
tial acoustic gain has been devised"
This formula,
24
TEST LOUDSPEAKER
/IN ROOM "A"
TEST LOUDSPEAKER
90
IN ROOM
85
"B"
TEST LOUDSPEAKER
IN ROOM "C"
80
D1
effects of room
ti
75
size, shape, absorption, and speaker
\
70
65
placement on the
final response
TEST LOUDSPEAKER
IN ANECHOIC CHAMBER
S.G.B.F. = 20 loglo [-D.
1-A
compariof the same
loudspeaker in four
different environments showing the
Fig.
son
curve.
Therefore, 20 logro
80
100
125
160 200
250
315 400
500 630
800
100
100
125
160 200
250 315 400 500 630 800
1k
100
23.5 dB SPL.
It is theoretically
125
10k
FREQUENCY (HERTZ)
65
Fig.
ORIGINAL ACOUSTICAL
RESPONSE OF LOUDSPEAKER
IN REVERBERANT CHURCH
60
INVERSE OF FILTERS'
ELECTRICAL RESPONSE
55
50
45
FINAL ACOUSTICAL
RESPONSE OF LOUDSPEAKER
40
AFTER ACOUSTA.VOICING
35
30
80
100
100
125
160 200
250 315 400 500 630 800 100
125
160 200
250 315 400
1k
10k
Nature of Acoustic Feedback. The
basic theory of amplification9.10'11
would lead us to expect that the
maximum acoustic gain (loudness)
we could achieve with any sound reinforcement system would be as follows: Assume that a person talking
two feet from an open microphone is
generating at the microphone diaphragm 70 db SPL, and that a loudspeaker is mounted 30 feet above the
microphone diaphragm. Further, assume that free -field conditions exist.
What maximum SPL can we expect
to generate at 4 feet from the loudspeaker ( the distance at which professional loudspeakers are rated for
efficiency) before acoustic feedback
should occur.
Naturally we would expect feedback to occur whenever the sound
from the loudspeaker reached the
same SPL at the microphone's diaphragm as the talker's voice, inasmuch as that represents unity gain.
Under the conditions described, the
=
Wallace Clement Sabine, Collected Papers on
Acoustics, Harvard University Press, Cambridge, Mass., 1922, page 4.
125
sponse.
FREQUENCY (HERTZ)
distinct, free from each other and from
extraneous noises."12)
500 630 800 100
2A-Correction
of the reverberant
field response, with
allowance made for
normal air absorption, by AcoustaVoicing filters. Also
included is a comparison of the filters' inverse electrical response with
the original uncorrected acoustic re-
SPL from the loudspeaker could be
raised as high as the SPL at the
microphone diaphragm from the
talker's voice (70 dB SPL). Add to
this the inverse -square -law loss of
the SPL at 4 feet from the loudspeaker (sound pressure level decreases 6 dB for every doubling of
the distance), compared to the SPL
at 30 ft. from the loudspeaker:
30
4
7.5. Thus, 20 loglo 7.5 = 17.5
dB. Therefore, we would expect to
be able to approach 70 + 17.5
dB SPL at 4 feet from the loudspeaker, or 87.5 dB.
To a person sitting 80 ft. away
from both the talker and the loudspeaker, we would expect the
talker's voice unamplified to arrive
at his ears with an SPL of 38dB SPL
at the listener's ears. (80/2 = 40;
20 login 40 = 32 dB; 70
32 =38 dB) The sound from the loudspeaker would arrive at the listener's
ears with an SPL of 61.5 dB. (80/4
= 20; 20 login 20 = 26 dB; 87.5
26 = 61.5 dB) This would mean
that the acoustic gain (61.5 dB 38
dB) would be 23.5 dB SPL at 80 feet.
A formula for calculating poten-
-
-
-
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AmericanRadioHistory.Com
,
30
[
2
80
80
l
possible to
exceed unity gain slightly if the
phase angle is manipulated so as to
ensure that no amplitude exceeding
unity gain passing through the entire system, including the room, has
a phase angle equal to 2N radians
(N = 0, 1, 2, etc.) By inference,
then, feedback that occurs before
.
reaching this theoretically practical
limit is due either to a peak in the
amplitude response of the combined
electronics, the electro -acoustic
transducers, and the acoustic environment, or to a detrimental phase
relationship between all these components at the feedback frequency.
To further complicate the basic
nature of the problem, electro -acoustic transducers have resonance
points, and the acoustic environment in a large hall has thousands
of normal modes in the usable audio
spectrum.
Acoustic feedback, which is the
product of the auditorium's high -Q
modes in combination, plus the electro -acoustic transducer's response,
plus the coupling of the two systems
together, can on occasion reduce the
actual realized acoustic gain from
+23.5 dB to -2 dB or less. When
this occurs, the auditorium in question rapidly begins the expansion of
its reputation of "having trouble with
sound."
It is demonstrable that the sound
system in such a room always feeds
back at one frequency at a time.
But this is by no means proof that
only one room mode is involved.
Quite the contrary. In a large auditorium, the normal modes overlap
significantly, and the response at
"s
Arthur C. Davis and Don Davis, "Microphones
for Sound Reinforcement Systems," AUDIO,
Dec. 1967, page 65.
AUDIO
22
D2
works out in our example as:
D, = 30' distance from microphone to loudspeaker
Ds = 2' distance from talker to
microphone
Do = 80' distance from talker to
listener
D2 = 80' distance from loudspeaker to listener.
f
50
Do
NOVEMBER 1968
the
crow
Ra
hundreds of Pioneer franchised high fidelity dealers across
the country, the SX-1500T is drawing enthusiastic attention
because it is a no-compromise receiver. Its highly sensitive
front end pulls in the most difficult stations ... and is
consequently pulling in the crowds. The SX-1500T was made
for the thousands who wanted the finest receiver
possible ... at a reasonable price.
The specifications and quality of the SX-1500T are
substantiated by its perlormance and, more
importantly, its sound. li boasts an output of
170 watts of music power, an extraordinary capture
ratio of 1 dB, a signal-to-noise ratio of 65 dB, and
harmonic distortion actually below 0.1% at half rated power (0.5% at
full rated power). FM sensitivity is outstanding at 1.7 uv.
Frequency response is 20 to 70,000 Hz i- 1 dB.
If you want a better receiver, don't be misled
pick the one with
the honest price. You owe it to yourself to compare the SX-1500T
with any other receiver on the market regardless of price.
See and hear the SX-1500T now. Or write for literature and name of nearest dealer.
PIONEER ELECTRONICS U.S.A. CORP., 140 Smith Street, Farmingdale, L. I., New York 11735
In
Dleaser...
-
PIONEER'S NEW SX-1500T AM -FM STEREO RECEIVER
170 WATTS, FET FRONT END, AND 4 IC's
NN
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N
Ib
e
KA
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U
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wiz
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Check No. 23 on Reader Service Card
AUDIO
NOVEMBER 1968
PIONEER ...More
Value All -Ways!
23
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ELECTRICAL AMPLITUDE
RESPONSE OF
ACOUSTA-VOICE FILTERS
f
5
dB
3.-
Fig
Tone -burst photographs of the transient response of critical -bandwidth band 20
Ik
100
10k
20k
Fig. 2B-This shows the electrical response of the Acousta-Voicing filters in the case of the
reverberant church shown in Fig. 2A.
any one frequency is dependent on
more than one mode.
Again, while it can be demonstrated experimentally that appreciable nulls exist between modes, their
close spacing and great similarity
dictate that they be treated as
groups. In a very practical sense,
any attempt to handle a high -Q,
single room mode requires a very
high -Q filter which, due to its high
Q, introduces a transient problem in
the response of the sound system
sometimes equal to or greater than
the room problem it attempts to correct. (See Fig. 3.) In extreme cases,
sound systems using such filters can
be found that exhibit feedback without a microphone being connected.
As the gain controls are advanced,
the sound system goes into feedback
as if a microphone were present. Removal of the non -constant k high Q filters immediately remedies this
phenomenon. The problem is aggravated by the impedance of the transmission link suddenly changing at
each of the resonant frequencies of
the filters.
Fortunately, it can again be experimentally demonstrated that controlling the overall amplitude and
phase combinations of the electronics, electro -acoustic transducers, and
the acoustic environment, with band
rejection filters of approximately
critical bandwidths, results in
greater gain and smoother system
response than that achieved by
band -rejection filters with narrower
bandwidth characteristics. Our ears
detect subjective loudness changes
in typical program material (music
and speech) in critical bandwidths.'{
Making filters narrower than these
critical bandwidths at any given frequency results in no audible improvement when compared to the
critical bandwidth filter. Since the Q
of a passive filter may be measured
by its "ringing" ( transient decay
distortion) it is of real interest to
determine how narrow in bandwidth
a band rejection filter can be made
and still pass undistorted transients.11 Happily, "ringing" does not
become a problem until the filters
are made narrower than the desired
critical bandwidths. Additionally,
the band -rejection filters of approximately critical bandwidth can be
built as constant k in circuit configuration, thereby avoiding the
aforementioned transient distortion
when they are introduced into the
electronic portion of the system.
(Early experimenters ignored this
"ringing" problem, but professional
sound contractors, motion picture,
recording, and broadcast engineers
cannot.)
Reverberant Coloration. The second major limitation encountered in
large auditoriums with well -designed and properly installed sound
systems is a reverberation decay
time that jumbles and garbles the
amplified speech. By subjective tests
of speech intelligibility, followed by
objective measurements of the length
of time given tones take to decay in
various auditoria, it was determined
over the years within what parameters of decay times that speech
14
Wolfgang E. Ohme, "Loudness Evaluation,"
Hewlett Packard Journal, Nov. 1967. Pages 6,
7, and lo.
General Radio Co. "Q of a Resonant Circuit."
Publication #STX-1o2, Oct. 1966.
24
rejection filters vs. narrower -bandwidth filters.
(A) Source -32 cycles of 1000 Hz signals. (B)
signal at output of link circuit.
intelligibility was affected. In a definitive paper given to the Audio
Engineering Society in 1955s, William B. Snow described and demonstrated the increased decay time that
resulted if the sound system operating near regeneration picked up the
natural room decay. It became apparent from Mr. Snow's data that,
in the attempt to raise the signal-tonoise ratio via a sound amplification
system, it also could increase the
decay time, at selected frequencies,
by as much as six to seven times
their original decay time. ( See Fig.
4.) Thus, in the attempt to get the
direct sound louder, the sound system, by operating close to feedback,
also made the re -amplified decay
time longer.
Mr. Snow's paper also showed
that, as the sound system was operated well below regeneration (-10
to -12 dB), it no longer amplified
the natural decay time of the room.
As shown earlier, if the acoustic response of a sound system is made
more uniform, acoustic gain increases towards its theoretical limit.
In so doing, the sound system then
has sufficient acoustic gain developed to allow it to be operated well
below the feedback point, thus eliminating the magnification of the natural reverberant decay times in the
room.
When a sound system has been
equalized to produce the most uniform amplitude response possible,
as measured in the reverberant far
field, there is considerable improvement in acoustic quality and gain.
The practical results to the user are
manifested as complete freedom
AUDIO
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NOVEMBER 1968
HAND CLAPS
NEAR SING POINT
HAND CLAPS
12 dB BELOW
SING POINT
I!ffinIrrl!lArIIII1IIIIIIUflIi
dIItIIIIfIÏIÏIfi
-
(A) Source 32 cycles of 1000 Hz signal.
Link circuit with
constant -k filter inserted and set for
(B)
-6 dB.
-
32 cycles of 1000 -Hz signal. (Source pulled
into ringing by filter.)
(A) Source
(B) Link circuit with
series -tuned induc-
tor
filter
and set for
inserted
-6 dB.
4-The effect of an amplification system, near regeneration, on the decay time
of a handclap in a reverberant space compared to the same system well below the
regeneration level.
Fig.
Courtesy of William
from feedback-it can now be operated well below regeneration, as excess gain is available-and causes
minimum excitation of the room's
natural reverberation. Sound systems have been Acousta-Voiced in
spaces with reverberation times as
high as 10 sec. at 512 Hz! The actual
in-the -field results often seem miraculous to the first time observer.
But it is demonstrable over and
over.
Basic Steps in Acousta-Voicing
Process. Because of the inextricable
dependance of successful sound -system equalization on the quality of
the sound system itself, it must be
recognized that Acousta-Voicing, in
order to succeed, must encompass
more than the mere application of
filter circuits to an existing sound
system.
Altec Acousta-Voicing contractors, for example, follow a step-bystep method that ensures that no
vital link in the total chain of interacting components is overlooked.
These steps are:
1. Design a new system or re -design an old system of either the
central high-level or overhead distributed type (or necessary combination of the two that ensures sufficient electrical power to generate the
required acoustic power at the listener's ears, and that guarantees
even distribution without "hot" or
"dead" spots. This automatically
precludes re-entrant horns, sound
columns, loudspeakers placed on
both sides of a stage, loudspeakers
mounted in strings down side walls,
and other self-defeating but timeAUDIO
honored practices.
2. Perform complete tests of the
installed systems using accurate
calibrated test equipment. Tests
should include, but are not restricted
to, inspection of:
(A) Proper grounding of all components and circuits to a real earth
ground.
(B) Link circuits and loudspeaker -line impedances and their adjustment to optimum values.
(C) Hum, noise, spurious oscillations and crosstalk, and their
elimination, if present.
(D) Acoustic distribution of the
loudspeakers' output throughout
the audience area.
(E) Time -delay relationships to
ensure that the time relationship
between the live talker's sound
and the amplified sound is sufficiently short.
(F) Electrical levels to avoid an
early stage either being overdriven
or overdriving a subsequent stage.
3. After designing, installing and
testing the sound system, and only
when each of these steps is found to
have been properly accomplished,
can the adjustment of the sound system's acoustic response in the room
environment begin.
It is this third stage that is popularly identified with Acousta-Voicing. Because the interested observer,
such as the owner of a building with
a long acoustic tale of woe, observes
that his building ceases to be a problem to him, he not unnaturally assumes the "miracle" lies in the
Acousta-Voice* filters alone. Word
of such success spreads quickly, of
course. But unfortunately, many ex-
B.
Snow.
perimenters with equalizers are disappointed in their results. It should
be noted that when all three of the
foregoing steps are properly executed, it is our experience that
Acousta-Voicing always works. But
it cannot be performed by untrained
sound -system designers, engineers
without proper precision test equipment, or sound contractors without
access to both quality components
and equalizers. This third step
breaks down into three parts:
(A) Broadband equalization of
the overall acoustic response of
the system in the room.
(B) Narrowband treatment of
the feedback frequencies that the
room -sound system combination
prefers.
(C) The control of feedback triggered by proximity effects exhibited by the microphones.
4. The final step is usually carried out by the user to suit his own
tastes. This consists of varying the
overall broadband acoustic response
of the sound system to best please
his or his customer's ears. In some
cases, he may prefer to sacrifice
acoustic gain for an acoustic effect
beneficial to the program material.
He should be provided in all cases
with the necessary program equalizers to allow reasonable experimentation, but always of the type that
allows instant return to the calibrated base as set up by the AcoustaVoice* engineer.
The second part of the series will
discuss the design, installation, and
the actual Acousta-Voicing of a
sound system.
CONCLUDED NEXT MONTH
25
NOVEMBER 1968
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LIST OF EXHIBITORS
AUDIO'S Guide to the
1968
San Francisco
High Fidelity
Music Show
Civic Auditorium,
99 Grove St., San Francisco, Calif.
TIMETABLE:
October 31 (Thursday)
4:00 pm to 10:30 pm
November
1
(Friday)
4:00 pm to 10:30 pm
November 2 (Saturday)
1:00 pm to 10:30 pm
November 3 (Sunday)
1:00 pm to 9:00 pm
JUDGING FROM THE exciting new
products displayed at the New York
High Fidelity Music Show last September, the upcoming San Francisco
show should be equally attractive
to show goers.
Some manufacturers made extra special efforts at the N. Y. show to
create attractive exhibit rooms.
From a decor viewpoint, three exhibits captured our attention: Stanton , with two rows of modern-style,
leatherette chairs, each with stereo
headphones mounted on what appeared to be Luxor desk lamp
swivels. Simply sit down and swing
the headphones over. Good idea for
the home. Pioneer had a lovely
Japanese decor, Shoji screens and
all, complementing its exhibit rooms.
Pickering showed a variety of antique
instruments, together with historical
information. Other interesting exhibits included Garrard's SL -95 being operated with voltage varying
from 65 V to 125 V, while an electronic counter verified that motor
speed did not change. Crown's DC 300 amplifier was shown lighting up
four 150 -watt bulbs with 60 Hz fed
into the amp's input. Catch 'em all
at the West Coast Hi-Fi Show, October 31 to November 1.
ROOM
EXHIBITOR
412
Acoustic Research, Inc.
315
Altec Lansing
407
Corporation
Ampex
313
Audio Magazine
406
Bogen Communications Div.
422
Bose Corporation
316
R. T. Bozak Mfg. Co.
425
BSR (USA) Limited
417
David Clark Company, Inc.
321, 323
CM Laboratories, Inc.
419
Craig Corporation
413
Dynaco, Inc.
307, 309
Electro -Voice, Inc.
402
Elpa Marketing Industries, Inc.
405
Empire Scientific Corp.
403
Fisher Radio Corp.
303
Garrard Div., British Industries Corp
322, 324
Goodmans of England
415
Harman-Kardon, Inc.
304
JBL
414
JVC America, Ltd.
401
Kenwood
Here are some ear -catchers to
look for that were not mentioned in
AUDIO'S Hi-Fi Show preview last
month: CM Labs packed 'em into
its N. Y. exhibit room with a $1050
(yes, that's four figures) stereo FM
tuner that features digital readout
of frequencies on Nixie tubes (otherwise the tuner is fully solid-state).
It has 100 crystal -controlled frequencies, so there's no drift. Press
a button and the station clicks in.
There's a timer/programmer and a
remote -control option, too. Bogen
and Fisher both displayed Varactortuning receivers, each with a lowcost optional remote-control device
(connected by cable) for selecting
broadcast stations from a seat at the
other end of the room. The Fisher
model (Model 500TX AM/FM
stereo at $449.95) utilizes dual -gate
MOS devices in its front end (as
does the CM Labs stereo tuner mentioned previously) To our knowledge, these are the first consumer
uses of this advanced transistor type.
Show attendees visiting Panasonic's
exhibit could be seen trying out the
company's new headphones with
a complete battery -operated FM
stereo receiver mounted inside. Price
.
-
ROOM
EXHIBITOR
408, 410
Koss Electronics, Inc.
305
Martel Electronics
Nikko Electric Corporation of America 427
326
Panasonic -Matsushita
404
Pickering and Company, Inc.
Pioneer Elect. (USA) Corp. ...317, 319, 325
320
Rectilinear Research Corp.
426
Sansui Electronics Corp.
302
H. H. Scott, Inc.
328
Seeburg Corporation
Sherwood Electronic Laboratories, Inc.. 311
306
Shure Brothers, Inc.
308, 310
Sony Corp. of America
416
Stanton Magnetics, Inc.
409
Superex Electronics
411
Tannoy (America) Limited
TEAC Corp. of America
Toujay Designs
UTC Sound
418,
United Audio Products, Inc.
Wharfdale Div., British Industries Corp..
www.americanradiohistory.com
AmericanRadioHistory.Com
314
327
420
301
is expected to be under $100. H. H.
Scott spotlighted its new "Designer
Stereo" AM / FM stereo / phono
"consolette," which also has LP storage space. Sherwood showed a
compact for the first time, its Model
S-6000. The 100 watt, AM/FM
stereo compact gives the user a
choice of turntables from among
Garrards, Duals or Sherwood's own
SEL -100 (a photo -electric actuated
turntable with piano -key controls).
Price is $419.50 plus speakers and
turntable. Superscope showed its
Model 630 stereo tape recorders, a
$379.50 unit with three tape heads,
echo and sound -on -sound facilities,
fader -type level controls, and a noise
elimination circuit. Dynaco entered
the loudspeaker market, displaying
a bookshelf speaker system imported from Europe. Containing two
drivers, it is expected to retail for
about $80. Elite showed small air suspension speaker systems, "Sound
N' Color," with decorator -color enclosures. Priced at $24.95. Marantz
expanded its line with a lower -priced
FM stereo tuner (Model 20 at
$395.00) and a lower -priced AM/
FM stereo receiver (Model 19 at
$495.00)
.
AUDIO
26
423
NOVEMBER 1968
the new ELPA PE-2020 Automatic turntable lets you
escape
from the
ordinary
Here's why
(1) The Exclusive 15° Vertical Tracking Angle Adjustment.
For critical listening and perfect sound reproduction,
records should be played with the stylus at a 15`
vertical tracking angle. The new ELPA PE -2020 is
the only automatic turntable that permits the
critical listener to do this for a single record,
in single manual play
or for any record in a
stack in multiple automatic play. This feature
gives the ELPA PE -2020 the precision of a fine
manual turntable, and a greater precision in
...
-
multiple play than any other automatic turntable.
(2) Stylus Protection. It is impossible to damage
the stylus of the ELPA PE -2020 by lowering the
tonearm onto an empty platter. Should the turntable be
switched on accidentally, the tonearm will refuse to descend
if no record is on the platter.
(3) Automatic Scanning. You don't need to adjust the new ELPA
PE -2020 for various size records. The scanning device automatically determines the size of the first record on the platter
and automatically adjusts the tonearm to descend in the proper
play position.
(4) Simplicity Of Operation. One lever controls all modes of
operation: Start, Stop, Repeat, Cueing, Pause, and Lift making
the ELPA PE -2020 the easiest automatic turntable to operate.
The single control is located at the front of the turntable and is
easily accessible even in confined quarters.
(5) Anti -Skating. The most sensitive anti -skating device on any
automatic turntable. Combined with an exact adjustment dial
to compensate for stylus shape, size, and tracking weight. Less
wear on your records, more perfect sound reproduction.
-
AUDIO
NOVEMBER 1968
Check No. 27 on
(6) Motor Driven Cueing. The most advanced form of cueing
today. No extra levers, no viscous -damped hand controlled
manual devices. Eliminates accidental slips of hand striking
the tonearm.
AND THERE ARE MANY., MANY MORE SUPERLATIVE FEATURES ON THE NEW ELPA PE -2020.
Don't make a buying decision on an automatic turntable without
seeing the finest ... the new ELPA PE -2020. See it at your high
fidelity dealer, or write for full literature and name of nearest
franchised dealer. ELPA MARKETING INDUSTRIES, INC.
New Hyde Park, N.Y. 11040
Re oder
Service Card
27
Audio
Engineering
Society
Celebrates
20th
Anniversary
C G. McPROUD
believe you are serving a much neglected field, in a highly adequate
manner.
Now that the audio engineer has
been dignified by a specialized publication, which will tend to draw the members of the field together, is it not time
for him to have an organization of his
own?
I have in mind an association similar
in function and purpose to the I. R. E.
and S. M. P. E. in their respective
fields.
I will be glad to correspond with anyone interested in this matter.
Frank E. Sherry, Jr.
7051/2 W. San Antonio St.
Victoria, Texas
What do our readers think?-Ed.
One reader, at least, did something
about it, as is evidenced by his reply
in the succeeding issue, January,
1948:
Sir:
In the last issue, Mr. Frank E.
Sherry, Jr., suggested that audio engineering had grown to the point where
it needed a professional society of its
own.
C. J. LeBEL-first president of the Society
(1949), secretary, 1952-1965. Vice -President,
Audio Devices, Inc., Chief Engineer, Audio
Instrument Company, and formerly Chief
Engineer of The Maico Company, hearing
aid manufacturer. "C.J." was the guiding
genius of the Society, and a true audio
pioneer who firmly believed that audio
engineering was a profession separate from
radio or electronic engineering.
THE THIRTY-FIFTH CONVENTION
of the AES marks the 20th Anniversary of the founding of the Society.
For the last ten of these years, the
Society's activities have been well
publicized; its early history, however, is less familiar. AUDIO Magazine is proud of its part in the formation of the Society, since it was in
these pages that the following letter
appeared in December, 1947, eight
months after the magazine began its
life, as Audio Engineering:
Audio Association
Sir:
After receiving the first few issues of
your new magazine, I must say that I
A group of us, long active in broadcasting and recording, feel the same
way he does. Audio engineering will be
unhampered only when it has a society
devoted exclusively to its needs-controlled by, and run only to benefit, the
audio engineer.
We have been discussing this matter
for several months, and are preparing
to hold an organization meeting.
Will those interested in such a society please write the undersigned,
giving the following information:
Name
Mailing Address
Company
Title or nature of work
We will notify you of the meeting
date.
C. J. LeBel
307 Riverside Drive
New York 25, N. Y.
Obviously there had been some
previous discussion of the need for
such a society in the New York area,
and many audio men responded with
encouraging zeal. The first meeting
of audio engineers was called for
January 8, 1948, and a steering committee consisting of C. J. LeBel,
John D. Colvin, Norman C. Pickering, Chester A. Rackey, and the
28
writer, was appointed. The organization meeting was held on February
17, 1948 at the RCA Victor Studios
on East 24th Street, with 137 persons attending.
Among the reasons for forming
the Society was the need to establish
audio engineering as a separate profession. Also desirable was the provision of a means for publishing papers on the subject.
Even before the Constitution was
drawn up, the newly formed Society
began to hold technical meetings-.
the first on March 11, 1948, at which
Dr. Harry F. Olson gave a talk on
"Some Problems of High Fidelity
Reproduction," with demonstrations.
Through correspondence with
audio engineers throughout the
country, Mr. LeBel began to get responses in other cities, and sections
were organized in Denver, Hollywood, and San Francisco.
The first slate of officers was
elected September 28, 1948, and the
Society was finally officially in operation, with C. J. LeBel as President, Chester A. Rackey as Vice President, Norman C. Pickering as
Secretary, and Ralph A. Schlegel as
Treasurer-a post he holds to this
day. Mr. Pickering remained as Secretary for three years, and his post
was then taken up by Mr. LeBel,
who held it until his death on April
13, 1965. It was always "C.J.'s"
function to keep things moving, and
he did this well, devoting his time
indefatigably to the Society's activities.
The First Annual Convention was
held in conjunction with the Audio
Fair in October, 1949, at the Hotel
New Yorker, and the first West
Coast Convention was held in 1954.
Since then, the Society has held two
conventions each year. The Society's
first technical papers were published
in the AES section of Audio Engineering until January, 1953, when
the Journal of the Audio Engineering Society, now a quarterly association publication, first made its appearance. AES membership now
numbers some 4000, and active sections operate in New York, the Midwest, Washington, Los Angeles, San
Francisco, and Tokyo.
AUDIO
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NOVEMBER 1968
Some of the driving forces behind the AES's growth
JERRY B. MINTER-sixth president. Vice -President, Measurements
Corporation, Boonton, N.J., and
President of Components Corporation,
Denville, N.J. Fellow and past president of the Radio Club of America,
and a member of the Aircraft Owners
and Pilots Association.
ALBERT A. PULLEY-seventh
president and one of the original
Governors. Manager, general recording, RCA Victor Record Division,
New York.
SHERMAN
FAIRCHILD-tenth
president. Mr. Fairchild is president of
Fairchild Recording Equipment Co.,
and active in a group of companies
bearing his name. His financial aid to
the Society was instrumental in getting
the Journal started, and in providing
the preprints of convention papers.
DR. HARRY F. OLSON-thirteenth
president. Director, David Sarnoff
Research Laboratories, author of
several books on music and acoustics.
Dr. Olson was the first recipient of the
John H. Potts Memorial Award.
COL. RICHARD H. RANGEReighth president, and behind him, F.
Sumner Hall, fifth president, at an
early AES banquet. Colonel Ranger
was president of Rangertone, Inc.,
manufacturers of tape recording equipment, and his work on sync systems
for tape recording is the basis for many
present systems. Mr. Hall was President of Audio Equipment Sales,
manufacturer of accessories for studio
HERMAN HOSMER SCOTTfourteenth president. President H. H.
Scott, Inc., manufacturer of high
fidelity equipment, sound level meters,
and similar laboratory instruments.
Mr. Scott was the third recipient of
the Potts Award.
use.
WALTER O. STANTON-ninth
president. President of Pickering &
Co. Inc., and of Stanton Magnetics,
both of Plainview, N.Y.
AUDIO
DR. JOHN K. HILLIARD-one of
the original Governors of the Society,
and the thirteenth recipient of the
John H. Potts Award. Dr. Hilliard is
Director of Engineering, Ling-Altec,
Anaheim, California, and formerly
with the sound department of Metro Goldwyn Mayer.
29
NOVEMBER 1968
www.americanradiohistory.com
AmericanRadioHistory.Com
What
the Pro's
expect
in the next
20 years
LEO L. BERANEK
When AUDIO celebrated its 20th
anniversary last year, we asked a
number of the industry's executives
what they thought we could expect in
high fidelity in the next 20 years, and
they responded with their prognostications. Now that the Audio Engineering Society is celebrating its 20th
anniversary, we thought that a similar
set of prognostications from leaders
in the professional field would be
enlightening. We asked, and they
replied with the following estimates,
guesses, hopes, expectations, or
PROGNOSTICATIONS
30
Bolt Beranek and Newman Inc.
President, Audio Engineering Society
Loudspeakers are the weak link in
the high fidelity chain. To produce
clean bass at 40 Hz and 100 decibels
in a living room, the necessary magnetic and radiating structures cause a
displacement of a volume of air of
about 500 cm3 on peaks, which, for a
10 -inch diameter cone, corresponds to
a linear peak -to -peak excursion of 3
cm. Even if perfect electroacoustic
conversion were accomplished, the
standing -wave pattern in the room
would mess it up. This much loudspeaker displacement is required
simply to move the eardrum about
0.03 cm, corresponding to a maximum
volume displacement of only one -hundredth of the loudspeaker cone.
I prognosticate that by 1980 we shall
have microminature batteries-a development that will permit the hi-fi
listener to plug two tiny radio receivers
into his ears. Thus, the glories of perfect stereo reproduction will be his,
with flat response, no distorion, and
full loudness. Architects and wives
would cheer the new freedom from
living-room clutter. Assembly -line
workers using the hi-fi plugs could enjoy work -with -music that would be free
of the din and distractions of the plant.
Stereo plugs could also be designed
to pick up acoustic stimuli simultaneously so that the listener could use
music for background and yet remain
in normal acoustic contact with his
surroundings. Even the telephone receiver could incorporate electromagnetic shielding that blocks the background music when the receiver is
pressed against the ear.
BENJAMIN B. BAUER
CBS Laboratories
This time, instead of making prognostications about equipment and techniques, I wish to address myself to the
men and women who will engineer and
operate the world of sound.
You will witness (to paraphrase
McLuhan) the continued implosion of
our electronic space-time. What we
think of as being difficult today, by
comparison, will loom simple tomorrow as fresh complexities emerge to encompass the new interactions of the
medium with the message, sight and
sound, tactile (as in Burris-Meyer's
infrasonic theatre sound), olfactory,
gustatory, and perhaps even extrasensory influences. So you will have to
know more and think new to stay on
top. In the antiquity of 1967 one could
design a saleable loudspeaker, through
inspired "putzing" with random
sample cones and magnets. In 1968 and
beyond you will need to use holographic interferometry and write a
computer program to cure the cone
anomalies; or better yet-forget the
cone and use modulated ozone or something.
A new engineering philosophy more and -more will be needed: More care
with the time -space of experiments,
more attention to reliability and
economy, more human engineering
(for the maker, the user, and the repairer) , more interaction between the
scientist and the artist through quieter
machines, better soundproofing, and
better earmuffs-in short, more personal involvement in the fields where,
at any given point along the time coordinate, the human excels and the
machine falters.
AUDIO
NOVEMBER 1968
"The tracking was excellent
and distinctly better in this
respect than any other cartridge we haue
tested,...The frequency response of the
Stanton 681EE was the flattest of the car-
tridges tested, within ±1 dB over most
of the audio range."
From the laboratory tests of eleven
cartridges, conducted by Julian D. Hirsch
and Gladden B. Houck, as reported in
HiFi/Stereo Review, July, 1968.
To anyone not familiar with the Stanton
681, this might seem to be an extraordinary
statement. But to anyone else, such as professional engineers, these results simply confirm
what they already know.
Your own 681 will perform exactly the
same as the one tested by Hirsch -Houck. That
is a guarantee. Every 681 is tested and measured against the laboratory standard for frequency response, channel separation, output,
etc. The results are written by hand on the
specifications enclosed with every 681.
You don't have to be a professional to
hear the difference a Stanton 681 will make in
your system, especially with the "Longhair"
brush that provides the clean grooves so essential for flawless tracking and clear reproduction.
The 68 lEE, with elliptical stylus, is
$60.00. The 681T, at $75.00, includes both an
elliptical stylus (for your records)
and an interchangeable conical stylus (for anyone else's records). For
free literature, write to Stanton Magnetics, Inc., Plainview, L.I., N.Y.
Check No. 31 on Reader Service Card
AUDIO
31
NOVEMBER 1968
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Prognostications
LOU BURROUGHS
Electro -Voice, Inc.
JOHN M. EARGLE
RCA Record Division
Twenty years ago I made a prediction that the recipe for success in the
acoustic business was dedication to reproduction of flat sound in every link
in the chain.
Our dedication to this concept over
the past twenty years has reinforced
ray belief and that of my associates
that the function of the manufacturer
in the electro acoustic business is to
provide the user with the mirror image
of the original sound.
As we have strived to achieve this, it
became increasingly obvious that to
reach our objectives in one element
within the chain and not in another
would negate a great deal of the user
benefits. In the years ahead, we believe firmly that loudspeakers, microphones of all types, and of course the
electronics linking the pick-up and reproduction will be improved in terms
of versatility, flatness, reliability, and
ease in handling.
Revolutionary changes did not take
place in the past two decades, and are
not likely to occur in the next two. The
gains made in acoustic products have
been painstakingly achieved by the
combination of more sophisticated materials, better instrumentation, and of
course the incalculable aid of scientific
electronic data processing equipment,
which has made it feasible to perform
years of calculations in hours.
As true high fidelity, which might
better be described as natural fidelity,
becomes easier to obtain, it will be
more widely sought until every form
of communication may well bask in its
subjective benefits. The reproduction
of music, the reinforcement of sound,
intercommunication, indeed all forms
of audio transmission, will become better as a result of the continuing advances made because of the need of the
professional.
There is enough that we know will
happen in the next twenty years without having to speculate upon what
might happen. Here are some thoughts
which occur to me:
We will continue to break records as
we have in the past twenty years. In
electronic components this means better performance in less space and for
less money. Miniaturization need not
continue beyond a certain practical
limit. However, tape and disc speeds
will likely continue to diminish as new
developments make it possible to hold
onto, or even better, our current quality standards.
One of the "last frontiers" in audio
is the matching of loudspeakers to listening rooms. A year and a half ago
there was virtually no activity in this
area. This year it is a big business in
sound reinforcement as well as reproduction in the home. There are already
loudspeakers for sale with "black
boxes" that match room -loudspeaker
characteristics, and these are destined
to become far more sophisticated in the
near future. We will also see an increase in bi -amplification as well as tri amplification of audio channels as part
of a return to more sophistication on
the part of tomorrow's audiophiles.
Today's techniques in noise reduction will find their way into tomorrow's
products. This will come first to recorded tape and then to discs. These
techniques will result in recorded product in the home with signal-to-noise
improvements of 10 to 15 decibels, and
one of the consequences of this will be
excellent quality on tape at 3% ips and
superb quality at 71/2 ips. The heart of
the system would be a small unit, a
special kind of pre -amp, which would
be switched into the circuit to "decode" and restore to normal tapes or
records that have been processed from
32
specially compressed masters.
Noise reduction techniques will
make more practical a move toward
multi -channel playback in the home.
Ju- ` as two -channel stereo provided a
leap forward in realism over mono, so
multi -channel techniques-four and
even beyond-will again carry us forward. Few people have had the privilege of hearing a four-channel playback with reverberant information
separately recorded. The effect is awesome, and it truly enables us to recreate in our living rooms the ambience of
much larger spaces, from recital halls
to cathedrals.
In the recording studio certain
changes are inevitable. Even more so
than today, pop music will be created
in the control room, and the sky will
be the limit as far as the use of signal
processing equipment is concerned.
Automation, currently a reality in the
areas of master tape and lacquer transfer, will undoubtedly move into other
studio areas.
Finally, there is the one development that we are all waiting for and
that is Sight and Sound, or whatever
you want to call it. Whether it is on
film, tape, or disc, we will have in our
homes video and audio on the same
medium. Research in this area is proceeding at quite a pace, and one dares
not hazard a guess as to which method
will win out.
IRVING JOEL
Capitol Records, Inc.
Twenty years ago, five 12 -inch 78 rpm records sold for $7.50. Today the
same amount of music is recorded on a
single stereo LP and lists for $6.00.
The record -making process is ex -
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
NOVEMBER 1968
the
a new addition to the AR family of
speaker systems
In October, 1967, after nine years of experimentation and development,
Acoustic Research introduced the AR -3a speaker system. It is the best speaker
system we know how to make, regardless of price. The most important
innovations in the AR -3a are two new hemispherical speakers which provide
very smooth mid- and high -frequency response, together with what one reviewer
called "virtually perfect dispersion. These two hemispherical speakers have
now been combined with an entirely new 10 -inch woofer to make the AR -5,
a speaker system almost as good as the AR -3a at a price about $75 lower.
The main difference between the two systems is that the AR -3a response
extends approximately one-third octave lower.
The cone of the AR -5 woofer is molded by a new low -vacuum process developed
especially for Acoustic Research. The unusual cone texture which results
reduces greatly the tendency toward coloration heard in conventional molded
cones of paper or polystyrene. At the cone's outer edge is a new suspension,
molded of urethane polymer. The cone itself has a compound curvature which is
new, it is in a new housing, and the voice coil attached to it is slightly larger and
longer. These internal improvements are complemented by a low 650 Hz
crossover frequëncy made possible by the wide range of the AR hemisphere
used for mid -frequencies. The crossover network is of the same type as is used
in the AR -3a, and uses 100 mfd of highly reliable paper -dielectric capacitors.
The two level controls are fully compatible with transistor amplifiers at all
settings, as are the controls of all AR speaker systems.
The AR -5 is priced from $156 to $175, depending on cabinet finish, and is
deep.
24" x
exactly the same size as the AR -2x and AR-2ax:131
"x
11/"
Impedance: 8 ohms.
Please write to us for technical data and descriptive literature.
ACOUSTIC RESEARCH, INC., 24 Thorndike Street, Cambridge, Mass. 02141
Overseas Inquiries: Write to AR International at above address
AUDIO
NOVEMBER 1968
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33
Prognostications
tremely complicated and requires
many steps between the sound pick-up
and the finished record, especially
since somewhere near the middle of the
process we have to cut a lacquer master
with a "hot dull chisel" and play the
finished record with a "round ball."
Where are we going? Pictures on
disc? It's already here, yes. They're
black and white and still, but the possibilities of color and motion are well
within sight. In fact, there is a magnetic disc which will reproduce color.
Tape, after a long awkward adolescence, is finally showing signs of becoming an excellent recording medium.
New tape formulas, high -quality, highspeed duplication, and new packaging
techniques will strengthen the usefulness of tape in the record industry.
I feel that in 20 years the phonograph record as we know it today will
be retired and in its place we will have
a record which will be manufactured
with a photographic process and the
reproducer will scan this record electrically thus eliminating all mechanical parts. In twenty years we will
count all our achievements and nostalgically look back to the "good old
days."
JOHN T. MULLIN
What of the future? We will ultimately find a practical limit to the
number of tracks that may be put on a
single tape. Then may come development of a continuous cross scanning
system similar to that employed in
video tape recorders, with the record
head multiplexed at video switching
rates to provide up to possibly 200
separate inputs, each sampled about
45,000 times per second. Synchronous
multiplex switching on playback would
permit selection and mixing of any
channel or channels as desired.
A special microphone may be developed, having an extremely narrow
pick up angle which may be scanned
across a full symphony orchestra in
synchronism with the cross scanning of
the tape, resulting in a "continuum"
recording wherein any small area of
the orchestra may be later mixed and
balanced against the others. Ten or
twenty years should see solution to
some relevant problems which seem
impossible today. Among these are
electrically scanning the narrow acoustical beam at' rates up to 45 kHz and
microphone response up to several
megahertz. System noise must be retained at extremely low levels and the
vast quantities of information must be
recorded with minimum consumption
of tape.
Mincom Division, 3M Company
LOREN L. RYDER
Nagra Magnetic Recorders, Inc.
Studio recording techniques have
changed markedly since the introduction of stereo tape recording. Today,
eight -track, one -inch tape systems are
providing master recording facilities of
great flexibility, particularly enabling
small groups of electronically oriented
musicians to achieve acoustical effects
never before heard in the history of
music.
Being introduced at this time, are
sixteen- and twenty -four-track mastering recorders, utilizing two-inch tape.
Their potential for the creative recording artist will be enormous.
My field is sound for motion pictures. I can well remember back in
1929, when working at Paramount, I
designed one of the first portable sound
recording trucks-it weighed 91/2 tons.
Today I am the U. S. representative of
Kudelski, and we sell the 14 -pound
self -powered Nagra-a weight reduction factor 1357 to 1.
During the last twenty years most
consumer products have been made to
give better service, and to be more
trouble free, simple to operate, and
more attractive. For the most part they
have found a correct size and weight
34
for utility. Look at the automobile. My
present car is about the same size and
weight as my 1940 car, but my present
car has been 50,000 miles and it has
never failed. My color television set is
now over ten years old. It has had one
complete replacement of all tubes and
a tune up. This is reliability.
In the field of professional sound
motion pictures, I do not expect much
reduction in size and weight of production recording equipment. The
great improvement in the future will
be in the "in plant" handling of sound
for better dramatic presentation. Our
present compositing procedure where
we combine dialogue, sound effects,
and music are based on the procedure
developed in the early 1930's. They are
obsolete and everybody knows it-oh!
what an opportunity for a break
through.
The greatest change is going to take
place in sound movies for the home.
"Do it yourself sound movies." All the
present systems are too cumbersome,
too expensive and too unreliable. I
venture that this change will not take
twenty years. The big thrust forward
should be in two to five years.
The new method of taking and presenting sound motion pictures in the
home must be simple for the beginner,
but for the more sophisticated it must
have the capability of editing, inserting
silent scenes and superimposing sound
along with sound effects and music.
Amateurs should be able to acquire
enough experience so they can make a
professional motion picture.
LAWRENCE
J.
SCULLY
Scully Recording Instruments Company
One of the questions most frequently
asked of us at Scully is "Where will it
end?" This question, from our friends
in recording studios, refers to the confusion created in the industry in the
past few years by the ever-increasing
number of tracks required for today's
recording techniques.
AUDIO
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NOVEMBER 1968
Should you be a nitpicker...
Should you be a nitpicker when it
comes to selecting a stereo deck? Only
if you want to get yourself a deck
you'll be happy with for years to come.
Because every manufacturer claims
to have the "guts" to make the best
sound. But, if you had the opportunity
to "tear apart" most of the tape
recorders on the market, you'd
find a lot of surprises inside.
Like flimsy looking little felt pressure
pads to hold the tape against the heads
which actually cause the heads to wear
out six to eight times faster than
Ampex heads.
Like stamped sheet metal and lots of
other not-so-solid stuff that gets by
but who knows how long? And all
kinds of tiny springs and gadgets
designed to do one thing or another.
(If you didn't know better, you'd
swear you were looking at the
inside of a toy.)
Like heads that are only adequate.
Heads that might work fine at first, but
wear out sooner and diminish the
quality of sound reproduction as
they wear.
There are lots of other things, but
that's basically what not to get in a deck.
Okay, now for a short course in
what to get.
Exclusive Ampex dual capstan
drive. No head -wearing pressure pads.
Perfect tape tension control, recording
or playing back.
Exclusive Ampex rigid block head
suspension. Most accurate head and
tape guidance system ever devised. Solid.
Exclusive Ampex deep gap heads..
Cost about $40 each. Far
superior to any other heads on the
market. Last as much as 10 times
longer. There's simply no comparison.
So much for the "general"
advantages of Ampex decks. Ready to
nitpick about specific features on
specific machines? Go ahead. Pick.
Pick the Ampex 755 for example.
(This is the one for "professional"
nitpickers.) Sound -on-sound,
sound-with-sound, echo, pause control,
tape monitor. Three separate Ampex
deep gap heads.
n
Model 755
A deck
for nitpickers.
AUDIO
NOVEMBER 1968
Or, pick the 1455. For lazier
nitpickers, because it has automatic
two -second threading and automatic
reverse. Plus sound -with-sound, pause
control and tape monitor. Four
separate deep gap heads.
One more thing you should get on
your next deck, whichever one you
choose: the exclusive Ampex
nameplate on the unit. Just big
enough to let everybody know you've
got the best. (Who says a nitpicker
can't be a name-dropper too?)
So, pick, pick, pick. And you'll pick
Ampex. Most straight -thinking
nitpickers do, you know.
AMPEX
AMPEX CORPORATION
CONSUMER EQUIPMENT DIVISION
2201 LUNT AVENUE
ELK GROVE, ILLINOIS 50077
-v2
Model 1455
And a deck
for lazy nitpickers.
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35
Prognostications
Most of us will remember when two track stereo, on quarter-inch tape, was
the only available system for multitrack recording. In the middle fifties,
three -track recorders using half -inch
tape became available and in the next
four or five years became the standard,
but not without some resistance from
the "old timers" who claimed the extra
channel was just a crutch to take the
place of a good A&R man. With the
advent of three -track recording, the
multi -track proliferation was on. It became obvious that if three was good,
four was better, and scarcely had
three -track consoles been completed
when the more progressive studios
shifted over to four -track on half -inch
tape. A concurrent development by
Ampex Corporation at this time, Selective Synchronization, was a large factor in the popularity of the multi -track
recorders. "Sel/Sync," as Ampex titled
this feature, enabled the studios to rerecord or over -dub on individual tracks
and still be able to listen to previously
recorded material on other tracks at
the same time. Sync techniques became a standard feature in the recording engineer's bag of tricks and opened
the way for the multi -track explosion
that was to come.
Eight-track recording, on one -inch
tape, was the next advance in the development, with several studios leading
the way. One of the earliest eight -track
studios was Atlantic Records, but the
successes of some independents in the
early sixties was probably most responsible for the industry move to eight track. Our Company was to take the
lead in one -inch recorders with some
studios going even further and installing twelve -track units. This latter configuration was about the limit for acceptable performance on one -inch tape,
but the race was on and the demand for
more and more tracks continued, and
the major equipment manufacturers
turned to two-inch tape!
Sixteen -track recorders, on two-inch
tape, are now coming into vogue and
will probably become the workhorse
unit in many recording studios. But,
even sixteen -track isn't enough for
some of the swingers! We've had requests for twenty-four and even thirtytwo track recorders. However, to attempt to answer the question raised in
the beginning, I feel that sixteen -track
on two-inch, eight -track on one -inch,
and two -track and full -track on quarter -inch will be the standard equipment in most studios in the next few
years. Because of some performance
limitations such as noise and cross talk,
I don't expect the twelve and twenty-
four configurations to become too popular, although we do expect some sales
in these areas.
However, these prognostications
must be considered with the knowledge
that I was one of those who thought
three -track and half -inch was "about
as far as they can go!"
STEPHEN F. TEMMER
Gotham Audio Corporation
Audio is a strange world. It is both
a business and a science, and yet the
business side and the scientific side
rarely if ever get together. Many business men feel that they can "make
windfall profits" by not only ignoring
scientific knowledge but even going
contrary to it. Let us hope that the future will bring a reversal of this trend.
Undoubtedly audio's greatest need
is education. There is no place in this
country today that offers training or
formal education to someone interested
in joining this industry. That is wrong
and the industry is beginning to feel
the pinch. The future must bring: increased knowledge derived from newly
established sources of information, increased integrity on the part of suppliers principally resulting from a
more knowledgeable consumer, and
genuine advancement of the art
through the interchange of ideas as
well as products between all of the
producing and consuming nations of
the world.
DANIEL R. VON RECKLINGHAUSEN
H. H. Scott, Inc.
Predicting the future is always a
difficult business. If you are right, you
are a prophet, and if you are wrong,
you should not try predicting in the
first place. However, there are certain
facts and facets which are likely to
materialize within the forthcoming
years.
Broadcast reception will become
more difficult rather than easier. The
number of FM stations in the world
may as much as double in the next ten
years, and their radiated power will
also increase. This, in turn, will make
reception of distant stations more difficult because of interference from the
more numerous local stations. Additionally, interference to reception from
other causes will also increase. There
will be more tall buildings acting as reflectors of radio waves with a consequent increase of multipath problems.
To make matters worse, I believe the
forest of roof -top antennas will slowly
disappear for aesthetic reasons. The
only way these interference problems
can then be minimized will be either by
the hopefully forthcoming development of a small directional indoor antenna, or by the introduction of cable
FM similar to cable TV.
Other interferences will become
worse. If the present trend continues,
other services will be sandwiched into
the present broadcast bands, as wireless microphones are at present, and
the increasing use of electrical equipment will increase local interference.
Again, a small antenna and the use of
cable FM will help to suppress this
type of interference.
What about new broadcast services?
It is theoretically feasible to add a
third channel to the present FM stereo
broadcast system. This third channel
might carry reverberation of the music
being broadcast or other special effects;
however, it is doubtful that such broadcasts will come into being because of
the ponderous nature of the rule -making proceedings required by the Federal Communication Commission.
What about other areas? We can expect that the amplifier horsepower race
will continue and that the average amplifier power will increase at the rate
of approximately 5% per year. Equipment for the home is likely to remain
about the same size as at present, at
least as far as the front is concerned,
because knobs and dials have to be
operated by human beings who so far
have resisted all efforts towards miniaturization. The increased power also
means increased equipment dissipation, and sometime in the future the
term "cool -running transistor equipment" will be forgotten because semiconductors will be developed some day
which will be capable of operating at
temperatures of hundreds of degrees.
This is necessary to have increased
power from the same size package.
There are other areas in which predictions could be attempted, such as
loudspeakers, tape recorders, or records; but any such prediction would
be considerably more hazardous than
any of the above.
AUDIO
36
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NOVEMBER 1968
The $89.50 Mircord
with the $129.50 features
The new Miracord 620 has most of the
features more expensive record
changers offer plus some that are
exclusive to Miracord.
For example
tonearm that is dynamically balanced in all planes by means of
an adjustable counterweight. A gram
calibrated knob and pivot bearing for
precise tracking force adjustment.
Continuously adjustable anti -skating
compensation, contoured to exactly the
correct value for every point on the
surface of the record. Remarkably
precise cueing. The ability to track any
cartridge at its recommended stylus
setting to well below 1 gram. A balanced
4 -pole induction motor for precise speed
accuracy. A heavy pressure -formed
turntable platter for smooth, steady
motion. That's what the 620 offers that
other automatic turntables offer!
-a
AUDIO
NOVEMBER 1968
Here's what other automatic turntables
don't offer. Light touch pushbutton
operation-a Miracord exclusive. The
gentlest touch puts the Miracord into
automatic play -up to 10 records. Or
you can ignore the pushbuttons and play
the single records manually by simply
placing the arm on the record. Another
Miracord exclusive lets you repeat the
same record over and over. That's how
easy it is to operate the Miracord 620
and to enjoy its performance.
The Miracord 620 follows in the great
tradition of the 50H ($149.50) and the
630 ($119.50). Model 620. Miracord
quality at 389.50. See what we mean at
your hi-fi dealer. Benjamin Electronic
Sound Corp., Farmingdale, N.Y. 11735.
New Miracord 620
Check No. 37 on Reader Service Card
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37
AES
Exhibit
Sampler
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3
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tude.
.;
"..:r
4
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1
L,r_x.
The following sampling of the new
and interesting equipment to be shown
at the AES Convention and Exhibit
held at the Park Sheraton Hotel in
New York- City, October 21-24,
illustrates some of the professional
gear that serves to keep up the high
standards of the audio profession. In
addition to (or instead of) exhibit
booths, many manufacturers have
working demonstrations in suites
elsewhere in the Hotel.
i
how it began
...and now
AKG Division of North American Philips
Co. Inc. is featuring the new C -451E
F.E.T. condenser microphone as a
component of the Condenser Microphone Modular System. This concept
offers extreme flexibility and allows the
microphone to be adapted to all types
of recording and sound reinforcement
situations. By simply changing capsule,
power source, or accessories, the user
can accommodate practically any requirement. For example, there are four
capsules-CK-1, cardioid; CK-2, omnidirectional; CK-6, switchable from
cardioid to omni to figure -8; and CK-9,
an interference tube or "shotgun" attachment. All four use the same amplifier and power supplies-either battery
or a.c. These microphones use a single
AKG C-451E Basic Microphone System
i
Edison's Tin Foil Phonograph sketch, Nov. 29, 187
pair of wires with a shield, thus making
it possible to use the C -451E in a system in which dynamic microphones are
also used.
Altec Lansing is featuring an idea,
rather than a product. The novel idea
is "Acousta-Voicing," a total programmed approach to the design, in-
ment used in tuning the sound installation, as well as instruct listeners in the
advantages of the system.
Ampex Corporation will display most
of its professional audio line, but the
"star" of the show is expected to be the
new MM -1000-16-a 16 -channel mas-
ter recorder recently introduced. This
model, like the 24 -track unit, uses twoinch tape, while the similar 8 -track
model uses one -inch tape. Conversion
from 8 to 16 to 24 channels is easily
Ampex Master Maker -1000
Altec Acousta-Voice Filter Set
stallation, testing, and tuning of a high quality sound system. The system
involves complete testing of all the important parameters of the installation,
including acoustic frequency response,
followed by a tuning of the room in
much the same way as a pipe organ is
tuned to its auditorium. On completion
of the "Acousta-Voicing," the system is
said to be capable of driving all frequencies in the room without fear of
uncontrolled feedback or reverberation
which would mar the reproduction.
Altec will exhibit some of the equip-
38
AUDIO
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AmericanRadioHistory.Com
NOVEMBER 1968
Humanized because ...
research on the physiological reaction
of the human ear to sound pressure
led to the development of a headphone
driver which functions with the human
ear as a unit, and is capable of generating full fidelity sound at close proximity to the entrance of the ear.
Humanized because...
of their seeming weightlessness.
Humanized because...
of their comfortable fit which allows
you to enjoy hours of stening pleasure without discomfort.
I
Humanized because ...
it permits you to enjcy transparent
reproduction of music and voice and
still remain in partial coitact with your
surroundings.
TYPICAL CUSTOMER COMMENTS
"Unbelievably fantastic."
"Superior musically to six other
types tested."
"Best sound yet."
"Best headphone at any price."
"Very comfortable to wear."
"Pleasure is now mine."
"Excellent sound anc comfort."
"The Best!"
"Prefer it to speakers."
"Very realistic sound."
Listen to the AKG K-20 or K-60 at your
dealer and convince yourself.
MICROPHONES HEADPHONES
OISTRIEWTED Ely
NORTH AMERICAN PHILIPS COMPANY, INC.
,r10 EAST 2ncl STREET, ,EW yORN, NEW rORK 10017
AUDIO
NOVEMHEK
I'w;
Check No. 39 on Reader Service Card
www.americanradiohistory.com
AmericanRadioHistory.Com
-
39
AES Exhibit Sampler
done with plug-in head assemblies, and
tape guides are instantly convertible to
accommodate either tape width. These
recorders permit each instrument or
group of instruments to be recorded
separately so that balancing and blending can be done at a later date by the
engineer and director after the musicians have left, allowing more time for
musicians to perform at each recording
session.
Audio Instrument Company, Inc. will
exhibit their Model 44 continuous -loop
reverberation unit. This rack mounted
fering sounds without noticeably affecting program material; to reject bands
of noise selectively and emphasize the
intelligence part of a program; to correct and equalize old records, microphones, speakers and amplifiers; and to
produce special effects by selective emphasis. Vertical attenuators mounted
in two rows on the front panel form a
visual configuration of the spectrum
shape, and a detachable memory bar
recreates any previously recorded spectrum in seconds.
The R. T. Bozak Mfg. Co. will feature
their new Model CAV-6-2 Co-ordinated Audio/Visual Perception mixer
amplifier, claimed as a step forward in
providing sensory perception to sound
reproduction. The unit has two outputs
to drive left and right speaker systems.
It has six inputs, each of which is divided to drive the left and right
speakers (through power amplifiers).
For each input a screwdriver adjustment on the chassis permits shifting the
balance between left and right outputs
to co-ordinate the apparent location of
Audio Instrument Co. Tape Reverberator
instrument utilizes a tape loop about
50 in. long which passes over an erase
head, a recording head, and seven play
heads. All but two of these heads may
be positioned at any desired point
along a slot in the panel so as to break
up the repetition time to avoid the objectionable feature of tape reverberation. Separate switches permit the use
of any desired number of the play
heads, and control is provided for reverberation time and reverberation
ratio. The entire unit is built for continuous use, and is of professional quality throughout.
B & K Instruments, Inc. will feature the
Model 123 Spectrum Shaper, which
permits dip -filtering of unwanted
sound in precise 1/3 -octave increments
over the entire audio range, with each
band individually adjusted from zero
to more than 50 dB of attenuation. The
Model 123 can be used to reject inter --
B & K Model 123 Spectrum Shaper
e
®
2
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,
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Bozak Model CAV-6-2
a sound source with the actual physical
location of the microphone. Each output has is own bass and treble controls.
Capps & Co., Inc. is featuring the
Capps Hot Stylus Unit which is a useful addition to the famous line of Capps
styli. This unit includes a control panel
and a stylus termination assembly
which is easily mounted on the cutting
head. The panel includes a stylus
temperature control and a meter, as
well as an on -off switch, pilot light, and
the line cord. Models are available for
most cutter heads. These units are used
to apply heat to disc recording styli so
as to soften the disc material at the
point of contact.
Crown International will show a number of versions of their recorders using
the PRO 800 computer logic control
tape transport. This mechanism combines a high -quality transport with a
computer which prevents damaged
tapes due to inadvertent mishandling
of the controls. The units are available
in two- and four -channel models for
40
Crown 800 Series Recorder
mastering and for general studio applications.
Dolby Laboratories, Inc. will introduce
a Duplicator Noise Reduction System,
Model 340. A special version of the
A-301 system, the new product is designed to replay noise -reduction tapes
at the high speeds used in the mass
production of pre-recorded tapes. With
state-of-the-art techniques in highspeed duplication, the noise level on
the duplicate is often limited by the
build-up of noise in the several tape
generations preceding the final one.
The Model 340 provides a way of effectively eliminating this noise contribution. According to the manufacturer,
this results in a superior quality "first
generation" duplicate. Here is the typical procedure:
A record company that uses the Dolby System and wants to issue a prerecorded tape of a particular performance can do so in two different ways.
If the master recording was made with
the Dolby A301, a copy of the master
can be made through another A301 in
the "compressed" mode. If the master
tape was made by conventional means,
it still can be copied through an A301,
also in the "compressed" mode. The
"compressed" tapes are sent to the
duplication plant where a high-speed
dubbing master is made with an A301,
the dubbing master still being in the
"compressed" mode. In the duplication
process, playback signals from the
high-speed tape reproducer are processed by the Model 340 and restored
to normal; the signals are then fed to
the high-speed slave recorders in the
usual way. Since the slave recorders
are receiving a signal which is the
equivalent of that from the orginal
master, the commercial pre-recorded
tape is, in essence, a first generation
AUDIO
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AmericanRadioHistory.Com
NOVEMBER 1968
PUT THEM
All
TOGETHER
.
..
1210 Master Unit
1220 Slave Unit
1260 Endless Loop Bin
THEY SPEIL ULTRA
-
HIGH SPEED
Combine the GAUSS 1210 Master Unit with the GAUSS 1260 Endless Loop Bin and add up to 20 GAUSS
1220 Slave units to form the most revolutionary high quality tape duplication system on the market:
the new Series 1200 Ultra -High Speed Tape Duplication System. Reproduces sound with crisp, clear
fidelity
... and fast too!
A 40 -minute Stereo 8 cartridge program in just 18 seconds. How? The secret is
FOCUSED GAP* recording. The process is uniquely GAUSS -- guarantees wider bandwidth, superior
fidelity, better signal-to-noise, lower distortion, top quality. Speed? How about 240 ips -- 2 to 4 times
faster than any competitor with optionally lower speeds of 60 or 120 ips. With the GAUSS 1260 Loop
Bin any master tape from 10 to 1800 feet can be run continuously without stopping to recue. Time consuming rewinding is totally eliminated. Snarls and tangles JUST DON'T HAPPEN! All machine time is
high quality profit -making production time. And that should be music to your ears.
*TM -GAUSS ELECTROPHYSICS, INC.
r
... specifications, prices, delivery ...
For the complete story
GAUSS ALECllVR.®Pll llYSJlCSq INC.
11
1653 12th Street, Santa
Monica. California 90404 U.S.A.
Check No.
AUDIO
please
41 on
an
write or call
-
MCA INC. company
Telephone. (213)451-9S76 / Cable: Gauss Santa Monica
Reader Service Card
41
NOVEMBER 1968
www.americanradiohistory.com
AmericanRadioHistory.Com
AES Exhibit Sampler
copy. The upper frequency limit of the
Model 340 is 500 kHz, which allows
duplication at up to 32 times normal
speed without sacrificing high -frequency response. Selection of 8, 16 or 32
times normal speed is obtained by
means of interchangeable control modules. Although all modules in the system are designed for high -frequency
operation, the overall complexity of the
Model 340 is similar to that of the
A301. Prices are reported to be the
same as for the A301 system.
Dolby Laboratories, Inc. will continue to show the Dolby S/N Stretcher
which has made such a hit in the past
two shows. Capable of giving a 10 -db
increase in usable dynamic range plus
generally cleaner, more transparent
recordings on original tapes, pressings
made from these master tapes are
much more attractive to the listener.
Already accepted by many major recording studios, the results are just
now appearing in finished phonograph
records, and consumers are fast becoming aware of the many advantages of
the system.
Electrodyne
Corporation
will
show
samples of its elaborate studio control
consoles, which incorporate all the
necessary controls, switching, equaliza-
Electrodyne ACC-1608 Console
tion facilities required in the preparation of master tapes in practically any
conceivable studio situation.
Electro -Voice,
Inc.
will be showing
their complete line of professional
microphones, ranging in size from the
649B lavalier up to the long-range
cardioid line unit Model 643. Among
most recently introduced models will
be the RE -15, a modestly priced unit
which is rugged and yet of broadcast
quality.
Gately Electronics will show their six channel "console in an attache case"
which makes it possible to record in
zontal endless tape bin for tape masters from 10 to 1800 ft. in length operates at speeds of 240, 120, or 60 ips.
The basic system is capable of producing over 1800 8 -track stereo cartridges
in each 8 -hour shift. As many as 20
slave recorders can be used with one
master and bin to produce over 36,000
cartridges per shift.
Gotham Audio Corporation will fea-
ture the complete Neumann Disc
Transfer System-shown for the first
time in this country. This system includes the SP -66 Transfer Console,
with a Telefunken M-10 A Professional
Tape Machine; a Neumann VMS -66
Computer Controlled Disc Mastering
Lathe; the Neumann SX-68 Stereo
Cutterhead; and the new VG -66S solidstate stereo electronics package for the
SX-68. The latter is the first all -solid -
Gately PM -1 Portable Mixer
locations where a mobile unit could not
possibly reach. Although operating on
117 V, 60 Hz, it requires only 10 watts
of power, yet provides for six inputs,
all of which can be switched to either
or both output channels. Output level
is + 24 dBm, at less than 1% THD
from 20 to 15,000 Hz. Available with a
variety of accessories to permit phono
inputs, or mic inputs of especially low
level, when required. Attache case is
only 18 x 121/4 x 51/4 in. high, and is
available in either black or olive finish.
Gauss Electrophysics, Inc. will be showing the new Gauss Series 1200 Ultra
High Speed Tape Duplicating system
which features tape speeds of 240, 120,
or 60 ips with ratio of 32:1 or 16:1 duplication. The system uses solid-state
electronics throughout, together with
the focused -gap recording process. The
revolutionary new Model 1260 horiGauss Electrophysics Horizontal Tape Bin
with Master and Slave Recorders
Electro -Voice RE-15 Microphone
A. Gotham's Neumann VMS -66
Disc -Cutting Lathe
B. Gotham's Neumann SP66S Control Console
state cutterhead electronics on the
market. This package contains all the
necessary amplifiers, equalizers, and
power supply equipment for use with
feedback stereo cutterheads.
Hewlett-Packard will feature a new
real-time audio spectrum analyzer, in
addition to their other acoustic measuring instruments (Sound Level
Meter, Loudness Analyzer). The
Audio Spectrum Analyzer, Model
8054A, looks at 24 1/3 -octave frequency
bands simultaneously and writes out a
spectrum in less than 30 ms, doing so
at rates up to 35 spectra per second. In
addition to having visual and analog
outputs, the new analyzer also has
digital outputs, giving it unprecedented
flexibility and speed in the processing
of data. The unit works this way: there
are 24 filters connected in parallel at
the input, and each filter has a detector
that determines the amplitude of signal
components in that channel. An elec-
42
AUDIO
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AmericanRadioHistory.Com
NOVEMBER 1968
Introducing three
new products from
Martin Audio
SONOMIX 601A
-A
...
NEW IDEA IN MIXERS
SIX CHANNELS
IN EUILDING BLOCK UNITS
- Line level for tape mixing
SEC )ND UNIT - Microphone preamp unit for live
BAS C UNIT
-ecording
THIFD UNIT-Nickel cadmium battery pack for
'emote recording
FOU 3TH UNIT
95 DB gain
200Q microphone input
100K Q line input
±4VU 600 52 output
XLR connectors on microphones and line
output
- Portable case
19 lbs.
with case and battery pack
$675.00 COMPLETE
VARISPEED III
- TAPE
RECORDER EFFECTS GENERATOR
studio
Vari::peed will vary the motor frequency
reccrder from 25 to 80 cycles and synchronize at
30, '8, 50 and 60 cycles.
o- a
Plugs directly into Ampex models 300-350-440,
Scul y models 280-282 and adapts to most other
stud o recorders.
INVALUABLE FOR
Sound effects
Correcting off speed tapes
Variable sound delay and changing pitch
Playing 33/4 IPS tapes on 71 IPS machines
Operating 60 cycle recorders on 50 cycles
Synchronizing film tracks
$395.00
STUDIO SYNC GENERATOR FOR 14000 CYCLE MODULATED FILM SYNC
Solid State modulated signal generator for
recording motion picture sync tracks on 1/4 inch
and multi -track non sprocket tape recorders.
$145.00
MARTIN AUDIO CORP.
A
56 West 45th Street New York, N.Y. 10036
Telephone 212-661-6987
VISIT US AT BOOTH 38, NEW YORK AUDIO ENGINEERING SOCIETY EXHIBITION
AUDIO
NO 'EMBER 1968
Check No. 43 on Reader Service Card
www.americanradiohistory.com
AmericanRadioHistory.Com
43
AES Exhibit Sampler
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Hewlett-Packard Audio Spectrum Analyzer
Langevin Mixer Console
tronic switch sequentially samples the
detector outputs in sync with a CRT
sweep to display amplitude vs. frequency. The speed of scanning (1 ms
per channel) presents the data virtually in real time.
tern basically includes the required
number of AM401 input modules, each
of which provides amplification, gain
Holzer Audio Eng. Co. (HAECO) is
showing the new "csg"-compatable
device which
stereo generator
makes it possible to combine the two
channels of a stereo program into a
monophonic signal without doubling up
-a
control, equalization, and switchingboth program and reverb lines. The
AM407 Program Module receives the
outputs of the various input modules
and provides for "reverberation point"
selection so that reverberation can be
recorded or just monitored without being recorded. The MG61 master gain
control provides for control of the entire system, as required.
frequency generating, modifying, and
controlling instruments, all designed to
perform their functions over a wide
range, and with an accuracy consistent
with the state of the art. The use of
these instruments with one or more
tape recorders offers a great flexibility
to composers in this new medium of
musical expression.
Nagra Magnetic Recorders, Inc. and
Ryder Magnetic Sales Corp. will be
featuring the Nagra portable tape recorder. Available in both synchronous
and non -sync models, the Nagra is
normally equipped with a mixing cor cuit for one microphone and a line or
bridging circuit, but with the addition
of another microphone preamp, two
microphones can be mixed readily. The
unit works at 15, 71/2, and 33/4 ips, and
will accommodate 5 -in reels with the
cover closed, 7 -in reels with the cover
Metrotech, Inc. will display its new
line of professional recorders. The
500A Series includes straight-line
threading, automatic tape lifters, inter-
Nagra Portable Sync Recorder
HAECO Compatible Stereo Generator
the "center," as is done when the two
channels are simply combined by paralleling. This unit thus makes it possible for an AM station, for example,
to broadcast stereo recordings monophonically with a program balance
more closely following what would be
obtained if it had been recorded originally in the mono mode. As a matter
of fact, the re-creation can be made to
have less than the correct amount of
"center" if such a condition should be
required. The encoding of the signal
will have no significant effect on the
stereo, but the mono reproduction will
be definitely enhanced, according to
the manufacturer.
Langevin will be featuring their
AM4A mixer assembly, which offers a
new concept in a sound mixer. The
building-block concept lets you buy
only the channels you need and drop
them into the AM4A housing, which
has an overall height of 7 in. and a
depth of 27 in. Width will vary with the
number of modules installed. The sys-
open, and works from a supply consisting of 12 standard "D" cells. The Nagra measures 121/2 x 8.7 x 4.3 in., and
weighs just under 14 lbs. Speed regulation is claimed to be .05 per cent or
better, and frequency response at 15
ips is from 30 to 18,000 Hz ±1 dB, and
at 71/2 ips it is from 40 to 15,000 Hz
+1 dB.
Sennheiser Electronic Corporation will
Metrotech 500A Series Recorder
locked controls, edit/cue functions, and
two -speed motors with automatic
equalization switching. Operating convenience is one of the principal advantages of the new design. A hinged head
cover provides easy access for tape
editing.
The R. A. Moog Company again brings
its wide line of electronic music composing equipment to the attention of
the engineer. These synthesizers are
integrated systems of modular, single -
feature their line of high -quality condenser microphones designed for studio
and professional applications. Among
them will be the MKH-110 which is a
special low -frequency test unit, and the
MKH-110/1, similarly good on the extremely low frequency ranges but capable of accepting high sound pressures
up to 5000 microbars. Two lavalier
models-both condenser types-will be
shown, Models MKH-124 and MKH125. In addition, test instruments and
headphones will be exhibited.
Shure Brothers, Inc. will exhibit their
line of studio dynamic microphones in
both cardioid and omnidirectional
AUDIO
44
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AmericanRadioHistory.Com
NOVEMBER 1968
GeLyeirri, .2eaclemitip me.semid ate
EW
Computer Logic Control
Pro 800 Transport
nimble -fingered tape -handlers there
exists a recurrent problem. It has been demonstrated time and again that anyone can ruin a
valuable tape by absentmindedly outsmarting the
interlock system of an otherwise safe tape recorder.
In the league of
MODEL CX 822
For the studio where flexibility
means creative productions.
this problem and similar problems arising in automated and remote control
applications, the CROWN Pro 800 was designed.
This recorder has a computer logic system using
IC's which prohibit all such destructive operations.
In answer to
The CROWN computer stores the last command
given it in its memory (forgetting all previous commands) and by a continuous knowledge of the
operating state of the machine (motion and direction), it takes all the necessary measures and
executes the command. This is all done without
time -wasting delay mechanisms.
Computer logic control brings to you rapid
error -free tape handling. It is actually
impossible to accidentally break a tape.
Call your CROWN dealer NOW!
MODEL CI 844
Four channel recorder for
perfect mastering.
FINEST TAPE HANDLING
MOST PERFECT REPRODUCTION
Performance as yet unequalled
Computer smooth operation
True straight line threading
Four years proven Solid
State circuitry
J
Extremely low noise electronics
THE HALLMARK OF CROWN
-
Patented Electro -Magnetic brakes
never need adjusting
QUALITY CRAFTSMANSHIP THROUGHOUT
MADE
ONLY
IN
AMERICA
Vl_
Uin
.
N( 7\
I
Mv,:.
BOX 1000, ELKHART, INDIANA 46514
Check No. 45 on Reader Service Card
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PHONE (219) 523-4919
45
AES Exhibit Sampler
contained regulated power supplies
operate from either 110-125 or 220-240
V a.c., 50 or 60 Hz.
Vega Electronics Corp. will he featuring the Vega S-10 Condenser Microphone, a solid-state unit with self-
contained battery. This
is a cardioid
model, finished in beige, with outputs
Tape-Athon Model 900 Logger
Shure Brothers Model 330 Ribbon Microphone
types, together with their line of microphone accessories. Shure's professional
mixer and its Audio Level Controller
are also expected to be displayed.
Spectra-Sonics will show the Model
101 Audio Amplifier, a solid-state circuit card offering a gain of 40 dB and
an output of +18 dBm. The low noise
level permits its use in any application
in an audio control system from micro-
;
I
iltiii°..:
A
fies Fi e
Spectra-Sonic Model 101 Audio Amplifier
phone preamp to line output amplifier.
The amplifier performs as if terminated by an external isolation trans-
Using triple -play tape, the 900 will log
over 400 hours of broadcasting on a
single 101/2 -in. reel. Frequency response at 15i!,2 ips is claimed to be from
200 to 3000 Hz with a S/N of 38 dB,
unweighted.
The 3M Company introduces a compact, remote overdub control as a professional mastering accessory. The
small control, which measures 6 by 6
by 4 inches, fits easily into recording
consoles. In addition to remotely and
electronically controlling overdubbing,
it also helps eliminate the possibility of
accidental erasure. The control is available as a factory -installed accessory
for 3M professional recorders at a cost
of $950.
is
United Recording Electronics Industries
presenting the Universal Audio 1176
Solid -State Limiting Amplifier which
utilizes an F.E.T. as a voltage -variable
resistor ahead of the first stage of amplification. Unique circuitry permits
severe limiting without added distortion, and no balancing is ever required,
former-thus providing freedom from
circuit grounds without the size or expense of transformers. Source impedance ranges from 50 ohms to
and
output loading can range from 600
ohms to 00 and it is stable under any
condition of pure capacitive loading at
either input or output.
,
Tape-Athon Corp. will show the new
Model 900 Logger, intended for application requiring long-time recording of
broadcast material. It operates at 15/.
or 15/;2 ips, with wow and flutter specifications of less than 0.3 and 0.5 per
cent, respectively, at the two speeds.
The Logger is equipped with an automatic reversing feature at each end of
reels to assure continuous recording.
Universal Audio 1176 Limiting Amplifier
says U.R.E.I. Attack time is adjustable
from less than 20 microseconds to 800
microseconds. This means that a 50 kHz peak is fully stabilized at the limited level within one cycle. Release
time is also adjustable from the front
panel from 50 ms to 1.1 seconds. The
1176 is rack mounted, and requires
only 31/2 in. of vertical space. Self-
46
Vega S-10 Condenser Microphone
of 50 ohms and high impedance. Output coupling is by means of a Cannon
plug, and a 20 -foot cable is supplied.
Also available is the S -10B, which is
the same except for an omnidirectional
pattern. A.c. supplies are available for
both models.
Wiegand Audio Laboratories
will be exhibiting their new
line of modular mixing console components and complete
factory -wired systems. The
W.A.L. Model 300 Master
Record-Reverb Module provides a master record straightline attenuator, two 22 -input
active combining networks, a
built-in solid-state reverb system, external reverb line input and output, direct line
output, a master echo -send
edgewise -mounted VU meter,
together with a master echo send control and two echo return -level mixers. In addition, a built-in reed relay is
employed to place slating information on the tracks in the
record mode. Another attraction of the W.A.L. booth will
be a Scully model 284-8 eight track recorder operating with
the W.A.L. console system.
Wiegand Model 300 Record-Reverb Module
AUDIO
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AmericanRadioHistory.Com
NOV'E4ll3ER 19(,8
Make Ckrtstmos A 14eotiJzLt®14ottdoy
Wish Your Family Merry Christmas This Year
With A New Heathkit Color TV ... A Better
Buy Than Ever With New Lower Prices
kit
NEW Deluxe Color TV With Automatic
Fine-Tuning-Model GR -681
$
Now There Are 4 Heathkit Color TV's ...
All With 2 -Year Picture Tube Warranty
GR -681
less
49995
cabinet)
-
The new Heathkit GR -681 is the most advanced color TV on the market. A strong
there
claim, but easy to prove. Compare the "681" against every other TV
isn't one available for any price that has all these features. Automatic Fine Tuning
just push a button and the factory assembled solid-state
on all 83 channels
circuit takes over to automatically tune the best color picture in the industry.
Push another front -panel button and the VHF channel selector rotates until you
reach the desired station, automatically. Built-in cable -type remote control that
allows you to turn the "681" on and off and change VHF channels without
moving from your chair. Or add the optional GRA-681-6 Wireless Remote
Control described below. A bridge -type low voltage power supply for superior
regulation; high & low AC taps are provided to insure that the picture transmitted exactly fits the "681" screen. Automatic degaussing, 2 -speed transistor
plus the built-in
UHF tuner, hi-fi sound output, two VHF antenna inputs
self-servicing aids that are standard on all Heathkit color TV's but can't be
bought on any other set for any price ... plus all the features of the famous "295"
and be convinced.
below. Compare the "681" against the others
$119.50
GRA-295-4, Mediterranean cabinet shown..
Other cabinets from $62.95
...
kit
G
R-681
...
...
now only
Deluxe
"295" Color TV... Model
GR -295
$44995
(less cabinet)
and packed with features. Top quality American brand
Big, Bold, Beautiful
new improved phosphors and low
color tube with 295 sq. in. viewing area
automatic devoltage supply with boosted B + for brighter, livelier color
...
gaussing
...
...
Automatic Color Control
Heath Magna -Shield
...Gainexclusive
Control for color purity, and flutter -free pictures under all
.
.
&
.
Automatic
preassembled IF strip with 3 stages instead of the usual two ..
conditions
wall,
deluxe VHF tuner with "memory" fine tuning ... three-way installation
custom or any of the beautiful Heath factory assembled cabinets. Add to that
the unique Heathkit self-servicing features like the built-in dot generator and
full color photos in the comprehensive manual that let you set-up, converge and
maintain the best color picture at all times, and can save you up to $200 over the
life of your set in service calls. For the best color picture around, order your
"295" now.
$62.95
G RA -295-1, Walnut cabinet shown
...
-
Other cabinets from $99.95
.
now only
Deluxe "221" Color TV... Model GR -227
$39995
(less cabinet)
Has same high performance features and built-in servicing facilities as the
GR -295, except for 227 sq. inch viewing area. The vertical swing -out chassis
makes for fast, easy servicing and installation. The dynamic convergence control
board can be placed so that it is easily accessible anytime you wish to "touch-up"
the picture.
. $59.95
G RA -227-1, Walnut cabinet shown
Mediterranean style also available at $99.50
now only
Deluxe "180" Color TV... Model GR -180
$34995
(less cabinet)
Same high performance features and exclusive self-servicing facilities as the
GR -295 except for 180 sq. inch viewing area. Feature for feature the Heathkit
tubes alone list for over
"180" is your best buy in deluxe color TV viewing
$245. For extra savings, extra beauty and convenience, add the table model
...
cabinet and mobile cart.
GRS-180-5, table model cabinet and cart
Other cabinets from $24.95
..
$39.95
Now, Wireless Remote Control For Heathkit Color TV's
Control your Heathkit Color TV from your easy chair, turn it on and off,
change VHF channels, volume, color and tint, all by sonic remote control. No
cables cluttering the room ... the handheld transmitter is all electronic, powered
by a small 9 v. battery, housed in a small, smartly styled beige plastic case. The
receiver contains an integrated circuit and a meter for adjustment ease. Installation is easy even in older Heathkit color TV's thanks to circuit board wiring
harness construction. For greater TV enjoyment, order yours now.
... $59.95
kit GRA-681-6, 7 lbs., for Heathkit GR -681 Color TV's
$69.95
kit GRA-295-6, 9 lbs., for Heathkit GR -295 & GR -25 TV's
$69.95
kit GRA-227-6, 9 lbs., for Heathkit GR -227 & GR -180 TV's
AUDIO
New Wireless
TV Remote Control
For GR -295, GR -227
& GR -180
$6995
New Wireless
TV Remote Control
For GR -681
$5995
47
No,, rV18[R 1%8
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AmericanRadioHistory.Com
Tki&s A 7ust Rtgk' 44ealkktt®
HEATHKIT AR -15 Deluxe Stereo Receiver
The World's Finest Stereo Receiver
the Heathkit AR -15 has received high
praise from every leading audio & electronics magazine and every major consumer testing organization. Here are some of the many reasons why. The AR -15
delivers 150 watts music power from its 69 transistor, 43 diode, 2 IC's circuit
75 watts per channel. Harmonic and IM distortion are both less than 0.5% at
full output for clean, natural sound throughout the entire audio range at any
listening level. The FM tuner has a cascode 2 -stage FET RF amplifier and an
FET mixer to provide high overload capability, excellent cross modulation and
image rejection. The use of crystal filters in the IF section is a Heath first in the
industry and provides an ideally shaped bandpass and adjacent channel selectivity impossible with conventional methods. Two Integrated Circuits in the IF
amplifier provide hard limiting, excellent temperature stability and increased
reliability. Each IC is no larger than a tiny transistor, yet each contains 28
actual parts. The FM tuner boasts sensitivity of 1.8 uV, selectivity of 70 dB and
harmonic & IM distortion both less than 0.5%
you'll hear stations you
didn't even know existed, and the elaborate noise -operated squelch, adjustable
phase control, sterel threshold control and FM stereo noise filter will let you hear
them in the clearest, most natural way possible. Other features include two front
panel stereo headphone jacks, positive circuit protection, transformerless outputs, loudness switch, stereo only switch, front panel input level controls, recessed outputs, two external FM antenna connectors and one for AM, Tone
Flat control, a massive electronically filtered power supply and "Black Magic"
panel lighting. Seven circuit boards & three wiring harness make assembly
easier and you can mount your completed AR -15 in a wall, your own custom
cabinet or the rich walnut Heath cabinet. For the finest stereo receiver anywhere,
order your AR -15 now. 34 lbs. *Optional walnut cabinet AE -16, $24.95.
...
-
kit AR -15
Wired ARW-15
'33995*
$52500W
NOW, THE TUNER AND AMPLIFIER OF
...
THE HEATH AR -15 RECEIVER ARE
AVAILABLE AS SEPARATE COMPONENTS
Y
_#....s.}_!ite
ilt
NEW kit AJ-15
$18995#
HEATHKIT AJ-15 Deluxe Stereo Tuner
For the nan who already owns a fine stereo amplifier, Heath now offers the
superb FM stereo tuner section of the AR -15 receiver as a separate unit. The
new A.1-15 FM Stereo Tuner has the exclusive FET FM tuner for remarkable
sensitivity, exclusive Crystal Filters in the IF strip for perfect response curve
and no alignment; Integrated Circuits in the IF for high gain, best limiting;
Noise -Operated Squelch; Stereo -Threshold Switch; 'Stereo -Only Switch; Adjustable Multiplex Phase, two Tuning Meters; two Stereo Phone jacks; "Black
Magic" panel lighting. 18 lbs. *Walnut cabinet AE -18, $19.95.
HEATHKIT AA -15 Deluxe Stereo Amplifier
NEW kit AA -15
$16995*
For the man who already owns a fine stereo tuner, Heath now offers the famous
amplifier section of the AR -15 receiver separately. The new AA -15 Stereo
Amplifier has the same superb features: 150 watts Music Power; Ultra -Low
Harmonic & IM Distortion (less than 0.5% at full output); Ultra -Wide Frequency Response ( ±1 dB, 8 to 40,000 Hz at 1 watt); Front Panel Input Level
Controls; Transformerless Amplifier; Capacitor Coupled Outputs; All -Silicon
Transistor Circuit; Positive Circuit Protection. 26 lbs. *Walflut cabinet AE -18,
$19.95.
kit AS -10U
$5995
(unfinished)
HEATHKIT AS -10 Acoustic Suspension System
This high performance Heathkit system features the extended bass response,
smooth high frequency response and low distortion that have made acoustic
suspension systems a favorite of thousands. The 10" woofer produces rich bass
down to 30 Hz, and the two 31/2" tweeters deliver clean, natural highs up to 15
kHz. The high frequency level control on the back of the factory assembled
cabinet lets you adjust the sound the way you like it and the system requires
only 10 watts to drive it, yet handles up to 40 watts of program material. Easy,
enjoyable one evening assembly
just wire the 2250 Hz L -C type crossover,
mount the speakers and sit back and enjoy the amazing performance. The rich
walnut of the assembled cabinet goes with any decor, or order the AS -10U and
have the added pleasure of putting the finish of your choice on it. Install either
horizontally or vertically. Order two for superb stereo now. 43 lbs.
-
HEATHKIT AS -16 Compact 2 -Way System
Don't let the small size and low cost fool ycu
the AS -16 performs with an
-
kit AS -16
$4995
authenticity comparable to many higher priced, larger systems. The 8" acoustic
suspension woofer and two 31/2" tweeters have smooth, lifelike response from
45 Hz to 20,000 Hz, without distortion or unnatural emphasis. The high frequency level control lets you balance the highs to suit your taste. Handles from
10 to 25 watts of program material and the compact 10" H x 19" W x 8'/4" D
walnut veneer cabinet is covered with a clear, tough vinyl to protect against
spills and scratches. Goes together in just 2 hours
the speakers are already
cabinet-mounted
just wire the 1500 Hz crossover network. Buy two of these
excellent Heathkit systems now and enjoy remarkable stereo at a reasonable
cost. 22 lbs.
-
48
...
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
NOVEMBER 1968
Gilt For Everyone On. Your List
HEATHKIT AD -27 FM Stereo Compact
The new Hcathkit AD -27 produces stereo sound comparable to many very good
stereo systems, for the simple reason that it wasn't engineered to meet the usual
performance standards of compacts. Heath engineers took their top rated AR -14
solid-state stereo receiver, modified it physically to fit the cabinet, and matched
it with the excellent British -crafted BSR McDonald 500A Automatic Turntable.
The result is the Heathkit "27" Component Compact. Here it is in detail: The
amplifier delivers an honest 15 watts music power per channel
enough to
drive any reasonably efficient speaker system
±I dB response from 12 Hz
to 60 kHz
channel separation is a remarkable 45 dB. Harmonic & IM distortion are both less than 170 at full output. The advanced transformerless output
circuitry provides lower phase shift and lower distortion plus protection against
transistor damage from shorted output leads. The performance of' the FM
Stereo tuner section is nothing short of outstanding. A flip of the rocker -type
power switch and the 31 transistor, 10 diode circuit is ready to go. Tune across
the dial with the smooth inertia flywheel tuning
the clarity & separation will
amaze you and you'll wonder where all those stations were before. Poor separation is eliminated thanks to the adjustable phase control and AFC puts an end
to drift. Stereo indicator light, filtered tape outputs and a low noise electronically
filtered power supply too. The precision BSR McDonald automatic turntable
has features normally found only in very expensive units, like cueing and pause
control, variable anti -skate device, adjustable stylus pressure, low mass tubular
aluminum tone arm with a famous Shure diamond stylus magnetic cartridge and
automatic system power too
the turntable will turn the system on & off. The
beautiful walnut cabinet with sliding tambour door will be a welcome addition
to any room too. For the finest stereo compact on the market, get your "27"
Component Compact now. 41 lbs.
-
...
...
...
NEW kit AD -27
-
$16995
HEATHKIT AD -17 Low Cost Stereo Compact
This new Heathkit Stereo Compact delivers quality stereo sound at a budgetsaving price. By taking the stereo amplifier section of the AD -27 above and
combining it with the top performing BSR McDonald 400 Automatic Turntable, Heath engineers were able to put together a stereo package that outperforms anything in its price class by a wide margin. And here's the AD -17
close-up. The 17 transistor, 6 diode amplifier puts out a husky 15 watts music
power per channel
sufficient power to drive most speaker systems. Harmonic
& IM distortion are both markedly less than other compacts in this range
less than % at full output. Channel separation is 45 dB. Front panel dual tandem controls for Volume, Bass and Treble let you adjust the sound to your
liking and the variable Balance control eliminates annoying level differences
between right and left channels. A stereo headphone jack is conveniently located
near the recessed inputs on the side of the cabinet. A front panel speaker on -off
switch lets you turn off the speakers for private headphone listening. Tuner
and auxiliary inputs allow you to add the enjoyment of FM stereo and tape
recording later if you wish. The high quality BSR McDonald 400 Automatic
Turntable features a variable cueing and pause control, adjustable stylus pressure adjust, adjustable anti -skating and many more precision features normally
associated with turntables costing much more. Comes equipped with a famous
Shure magnetic cartridge too. Easy, enjoyable 12-15 hour assembly is assured
through the use of circuit board, wiring harness construction and the easy to
understand Heathkit manual. Just wire the circuit board and install the assembled turntable in the handsome walnut finish cabinet
you'll have a stereo
compact that will look nice and perform great
the Heathkit AD -17. Order
yours today. 28 lbs.
-
-
1
-
NEW kit AD -17
$195
...
HEATHKIT AS -18 Miniature Speaker System
The new Heathkit AS -18 will remove your suspicions about the performance of
miniature speaker systems forever. Physically it's only 81/4" H x 151/4" W x 61/2" D
but it will outperform many larger systems that cost much more. Heath engineers
used well-known high quality Electro -Voice° speakers and good design methods
to produce the most surprising little speaker system you've ever heard. The 6"
acoustic suspension woofer produces full, rich bass down to an 60 Hz and the
21/2" tweeter delivers clear, natural highs up to 20 kHz
excellent performance
for most any system. A high frequency balance control lets you adjust the sound
to suit you. Handles 25 watts of program material. The speakers mount from the
front of the clear vinyl covered cabinet for easier assembly and better sound.
The AS -18 makes an ideal performance companion to either of the new Heathkit
Component Compacts above, and its perfect for anywhere you need superior
performance from a small space. Pick up a pair of these startling little performers for stereo. 16 lbs.
-
HEATHKIT
1969
Benton Harbor, Michigan 49022
In Canada, Daystrom Ltd.
Enclosed is $
Please send model (s)
Please send FREE Heathkit Catalog.
Please send Credit Application.
Name
FREE 1969 CATALOG!
Now with more kits, more color.
Fully describes these along with
over 300 kits for stereo/hi-f i,
AUDIO
NOVEMBER 1968
$3295
HEATH COMPANY, Dept. 41-11
NEW
color TV, electronic organs, electric guitar & amplifier, amateur
radio, marine, educational, CB,
home & hobby. Mail coupon or
write Heath Company, Benton
Harbor, Michigan 49022.
NEW kit AS -18
-
-
plr
c
sipping.
Address
City
L
State
Prices & specifications subject to change without notice.
Check No. 49 on Reader Service Card
www.americanradiohistory.com
AmericanRadioHistory.Com
Zip
CL -344
J
49
The Art of the
Small
Recording Studio
JOSEPH GIOVANELLI
THERE ARE MANY recording studios
whose products will never make the
"Top Ten," nor are they intended to.
This article will touch upon the activities of these studios, their probable
equipment requirements, and the problems they face.
How small is small? This covers a
wide range, and the answer about size
will provide an idea of the type of work
in which such studios are engaged. A
"studio" might merely consist of a
music teacher with a tape recorder who
tapes and sells to his students copies
of their performances. It may be someone who occasionally records a wedding ceremony with a view to selling
the recording to the bride and groom.
The small recording company might be
run by one man or a group of men.
Perhaps they make recordings for
would-be actors or singers to use as
audition material, or for teachers to use
as educational material. Probably the
small recording company will do all of
these things and more besides.
Generally speaking, all small recording studios have one thing in common.
Theirs is a custom service. They do not
produce records for the mass market.
They may make no more than one or
two copies from a given taping session.
Thus, each tape produced is custom
made to slit the individual requirements of the client. Whether it is rock
or chamber music, the products are
sold to the performers, seldom to the
general public.
The recordist might go to a highschool spring concert, tape it, and sell
tapes or discs to the performers and to
the audience. It would be impossible
for the large record companies with
their high overhead in terms of manpower, plant, and equipment to record
this same high-school concert and sell
the products at a price the audience
could afford to pay. It is obvious that
the small studio is not competing with
the giants for the same market. Therefore, their requirements in terms of
equipment, personnel, and studio facilities are considerably different.
The first consideration is the studio.
Some recording companies may not
even have a studio, especially those
who specialize in "dubbing" or making
copies from previously recorded material onto tapes or discs. This specialty
might be narrowed even further to
"air checks," the recording of programs
from radio or television in the hope of
selling their product to the participants
on such shows.
However, most small recording companies do have some kind of studio.
Such studios are usually small because
the number of people being recorded
at any given time rarely exceeds half a
dozen or so. This does not mean that
the small companies do not record large
groups of performers, however. In such
cases they may rent a hall for the purpose or use the group's own rehearsal
facilities as the recording studio. Of
course, there are studios with many
rooms where several recording sessions
or rehearsals can go on at the same
time, but these still come under the
classification of a small studio as opposed to the major recording companies.
Equipment Needs
The amount of recording and auxiliary equipment that the small studio
may own will vary, depending on the
type of work it performs, its budget,
and the ingenuity of its personnel. A
company that specializes in dubbing
obviously needs no microphones and
no console. All that is required is sufficient tape or disc equipment to carry
out the necessary functions. They may
or may not require some kind of equalizer to compensate for deficiencies in
clients' tapes. If the work involves recordings from radio or television, they
will often have the best obtainable AM
and FM receivers, and the best possible equipment for recovering sound
from the television channels. This last
is not easily obtainable commercially.
It is often specially built by or for the
studio.
When the company offers studio facilities-and most of us do-some kind
of mixing equipment will be required.
Generally, budget limitations prevent
ownership of eight- or twelve -track
equipment. We must make do with
two -channel stereo equipment, using
these two channels in much the same
way that large recording companies use
eight or twelve tracks. Over -dubbing
must be accomplished with a second
recorder rather than by taping track
upon track, with a view to later remixing.
The lack of such multi -track equipment imposes some considerable diffi-
50
culties on the engineer doing the mixing. If he does a poor mix, he has no
recourse but to re-record a given track
and hope that his mix on this particular over -dub was better than his previous mix. This calls for a considerable
amount of artistry, and most of us enjoy the challenge. After all, excellent
work was turned out before the advent
of all this multi -track equipment.
Therefore, small studios are not doing
the impossible in terms of producing a
fine product with limited equipmentlimited in terms of what is available to
the larger companies. In truth, much
of recording is art, not science. It is the
ability of the engineer which makes
the difference.
While not having the flexibility of
the larger companies, one can, with
proper care and patience, put out a
product which is as good as, and very
often better than, a similar product
marketed by a large record company.
Part of the reason for this is being able
to give a particular session more attention than it can be accorded in a large
company whose schedule is tight.
Another reason is that the number
of different pieces of equipment used
is far fewer than will be found in the
chain used by a large studio. For example, if able to make a successful
recording using a two -track original,
this master tape is used to make the
final discs or tapes for the client. This
is seldom possible in large installations
where virtually all taping is multitrack, requiring a mix -down before
duplication to the master disc. In addition to the fact that master tapes are
very often the originals, the number of
amplifiers, equalizers, limiters, and
other recorders through which the
signal must pass on its way from the
microphone to the final product is
usually far fewer in number in a small
studio than would be true of the large
house. Therefore, one can end up with
less distortion and with a wider frequency range.
One piece of equipment which is seldom involved in a re -mixing process in
a small studio, but certainly is in a
large one, is a recording console. I believe that a console for the small studio
is unnecessary since we are not recording more than two simultaneous channels. Of course, each channel may be
fed from a mix consisting of several
inputs. A mixer will serve the purpose
as well or perhaps better than a console. True, small studios lack the refinements of separate equalizers and
reverb facilities on each input, but for
their purposes these features are seldom necessary. Superb results can be
obtained by using overall echo, which
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
NOVEMBER 1968
The TEAC sound is getting around.
A round of hearty applause
-
from showroom to living room to sound studio. Aid why
not, with prestige performers like this one. Its totally unique
phase sensing auto reverse means continuous playback with
or without sensing foil. Worth up to four hours uninterrupted
performance! Another TEAC exclusive: a foolproof symmetrical
control system. Plus dual -speed hysteresis synchronous
motor for capstan drive, two exclusive eddy -current outer
rotor motors for reel drive. Four premium heads in a plug-in
unit, with four -track two -channel operation. Four solid-state
amplifiers, too, with silicon transistors for added strength
and sound quality. The top of the TEAC line!
Yes, TEAC delivers the biggest sound around, even from the
smallest models. Like the only cassette deck on the market
that works like
a big machine, thanks to its unique hysteresis
synchronous outer rotor motor. Other big exclusives include
pause control, digital counter and dual VU meter. It's the
latest concept in cassettes, with all -silicon transistor amp and
pre -amp, two specially -designed heads, four tracks and two
channels-for compact convenience, powerhouse performance
Small wonder!
Anyone for encores?
TEAC®
'EAC Corporation of America, 2000 Colorado Avenue, Santa Monica, California 90404
AUDIO
NOVEMBER 1968
Check No.
51
on Reader Service Cord
www.americanradiohistory.com
AmericanRadioHistory.Com
51
can be introduced at any time during
the overdubbing process.
Microphones must be given careful
consideration. Unlike the larger studios, the small studio, with a small
budget, must work with as few microphones as possible. Certainly we need
two high -quality condenser microphones. Generally these will be of the
omnidirectional type.
Then, too, small studios are often
plagued with poor acoustic conditions
when making remote recordings. Omnidirectional microphones will only
aggravate this situation. Therefore, I
believe that thg small studio needs at
least two microphones whose low -frequency range is limited, and whose
pickup pattern is both cardioid and
close -talk. Such a microphone will enable a singer to work as close to it as
he wishes in order to eliminate pickup
from other instruments or to eliminate
room reverberations. The lack of low frequency response from such a microphone makes it unnecessary to employ
separate equalization on that mixer input-an equalization capability which
we might not even have.
If possible, the studio should also
probably have a pair of cardioid microphones which have a wide frequency
range, in addition to the close -talk
mike just described. Thus, with half -a -
dozen mikes we are in a position to
meet the demands of most acoustical
environments in which small -studio
recordists are likely to find themselves.
Remote recordings also pose problems since, for the most part, equipment specifically for location recordings is generally not available. At least
one of the recorders and the mixer
must be readily detachable from the
remainder of the control room equipment so that it can serve as the remote
recording equipment.
Up to this point we have only discussed the equipment required to make
the original recording. If the customer
wishes a tape copy of the session, it is
no problem to copy from the master
tape as often as desired, but many
clients will require disc copies. This requires disc recording equipment. Discs
are far more difficult to make than
tapes.
Some small studios own their own
disc recording equipment, but others
prefer to make their own tapes and
farm out their disc recording work. Unless the operator of a small studio is
fascinated with the problems of disc
recording, farming out his disc work is
a very logical approach to the problem.
Also, unless he is mechanically inclined
and can build his own, a good disc re -
THE DOLBY A301 AUDIO NOISE REDUCTION SYSTEM
Making the
Master
Recordings
of the
Future
cording lathe will cost him several
thousand dollars. In addition, the recording head will cost a considerable
sum, especially if he plans to make
stereo discs.
In any case, if a person has never
cut a disc before, it will take him several months of frustration before he
learns to do so successfully. When you
stop to consider the investment in
equipment and time, the farming out
of your disc recording work looks very
attractive. I have made discs for more
than twenty years, so I know just what
a novice to this art must go through.
His problems are made more difficult
as the state of the art places more and
more exacting demands on the disc
maker.
We now have traced the activities of
the operator of a small studio through
the type of work that is performed and
the equipment used to perform that
work. The ability to make high -quality
tapes and discs is meaningless unless
his potential customers are aware of
his existence, of course. Budget limitations of the small studio permit only
minimal advertising. Therefore, one
must show his ability by turning out a
product of sufficiently high quality that
word-of-mouth and advertising will do
Æ
the trick.
Already in use in eighteen countries,
the Dolby system is making master
recordings which will withstand the
test of time.
The system provides a full 10 dB reduction of print -through and a 10-15
dB reduction of hiss. These improvements, of breakthrough magnitude, are valid at any time-even after
years of tape storage. This is why
record companies with an eye to the
future are now adopting this new
revolutionary recording technique.
features: Easy, plug-in installation
solid state circuitry modular, printed circuit
construction
high reliability, hands-off
A301
operation. Performance parameters such as
distortion, frequency response, transient
and noise level meet
quality professional standards.
Price $1950 f.o.b. New York.
response,
highest
NEW Remote Changeover option cuts costs,
enables one A301 unit to do the work of two.
NEW NAB and DIN level setting meters
simplify recorder gain calibration.
DOLBY LABORATORIES INC.
333 Avenue of the Americas
(212) 243-2525
Cables:
NewYork N.Y. 10014
Dolbylabs New York
Check No. 52 on Reader Service Card
52
AUDIO
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AmericanRadioHistory.Com
NOVEMBER 1968
sititteß
PAT -4 PREAMPLIFIER
89.95 KIT, 129.95 ASSEMBLED
IN
FM -3 TUNER
99.95 KIT, 154.95 ASSEMBLED
LASTING Q
the evolution of high fidelity, there have been some
stereo record, FM multiplex, and transistorization, to give some examples. Each of those changes
left its trail of obsolete equipment, frequently replaced with
much higher priced models. Through these periods of
change, Dynaco has maintained a level of quality so high
that our equipment is always current, never obsolete, and
always adaptable to the newest useful innovations.
Dynaco's underlying philosophy is to deliver exceptional
performance from designs so carefully and progressively
engineered that they defy obsolescence. We add new products only when we feel that they can make a contribution of
value to music reproduction. In each Dynaco high fidelity
component the total value of the separate parts is greater
than what you pay for the finished product, and you can
save even more by buying the kit.
Dynaco's separate components give you the ultimate in
flexibility and ease of installation. They can be interchanged
with full compatibility, not only with Dynaco units, but with
any other similar designs which are generally accepted as
being of the finest quality. No industry innovation can make
your system obsolete, and future changes, such as an
In
"revolutions"-the
ALITI
increase in amplifier power, can be easily and economically
accomplished.
The quality of performance obtained with the FM -3 tuner,
PAT -4 preamplifier, and the Stereo 120 power amplifier
cannot be matched in any single package regardless of promotional claims. Other Dynaco units which can interchange
with this system will also give similar results at lower power,
or with a bit less control flexibility at still lower cost, depending on the units chosen.
Whether you compare Dynaco with others by listening or
by laboratory test, you will find that Dynaco gives sound
closest to the original-with lucid clarity, without murkiness, noise or distortion. Every unit-whether purchased as
a kit or factory assembled, is assured of delivering the same
specified quality, for our reputation has grown through
directing our design efforts towards perfection rather than
to the planned obsolescence of yearly model "face-lifts."
You may find that your dealer does not have some Dynaco
equipment in stock, however, for the demand greatly exceeds
our ability to produce for a rapidly growing audience. Quality
is our first consideration, so we must ask your patience.
We believe you will find it is worth the wait.
STEREO 120 AMPLIFIER
159.95 KIT, 199.95 ASSEMBLED
Write for descriptive literature and complete specifications.
81UniaE0 ILI
AUDIO
3060 JEFFERSON
IN EUROPE
STREET,
PHILADELPHIA,
PA.
19121
WRITE: DYNACO A/S, HUMLUM, STRUER, DENMARK
NOVEMBER 1968
53
www.americanradiohistory.com
AmericanRadioHistory.Com
Audio Testing
in a
Broadcast Studio
FRED
L.
ZELLNER
American Broadcasting Company
FOR SOME TIME, there has been a
certain amount of confusion with regard to level measurements in vu,
DBM, PROGRAM LEVEL, PLUS 8, TEST
LEVEL, etc.
A DECIBEL (dB) is a unit of measurement which represents a ratio of
two (2) powers. It is usually used
to indicate the difference between
an input and an output, a before and
after, a yesterday and today. Just
as it might be said that the temperature has risen 4 degrees during the
morning, so it can be said that the
power in a particular circuit has increased 4 dB, or 10 dB, etc. Just as
in using a thermometer, there arose
a need to have some reference point,
such as zero; this same need arises
when using decibels. In the case of
the thermometer, there are several
reference points. There is one for
the CENTIGRADE thermometer, which
is set at the freezing point of fresh
water. There is a different zero for
the FAHRENHEIT scale, based on the
temperature of freezing a salt solution. The KELVIN scale has still another point for its zero (probably the
most logical, as well as the most
useful, scientifically), based on the
temperature at which all molecular
motion in an object ceases.
Similarly there are several reference points when it comes to a scale
based on decibels. Acoustically, a
zero reference was set at the threshold of audibility. But when it came
to electronic equipment using loudspeakers to overcome the background level in the average living
room, this zero was found to be way
up at 40 dB on this acoustical scale.
*Original paper was presented at the NAB Engineering Conference, April 1-3, 1968. A complete
transcript of the technical papers presented at
the conference plus a transcript of the FCC/Industry Panel discussion is available in a 256 -page,
plastic -bound book. Technical Papers Presented
at the 1968 NAB Engineering Conference,
$10.00, published by TAB Books, Blue Ridge
Summit, Pa. 17214.
Therefore, an arbitrarily set value
of 6 milliwatts of power dissipated
across 500 ohms was set as the reference power, and this level became
known as 0 dB.
All was well and good until it
came to measuring complex waveforms such as those produced by
normal speech and music. No longer
did RMS value have a meaning. The
average power level of speech and
music is much lower, compared to
the peak value, than for a corresponding sine wave with the same
peak. Sharp, thin peaks are the
rule greater spacing between peak
pulses is produced in short, sinusoidal measuring techniques no longer apply. Therefore, a special meter
was developed (with certain specific damping characteristics) which
would respond in a definite manner
to these complex waveforms. This
meter read a sort of average audio
power (as well as reading the RMS
value if a sine wave of 1 kHz was
used) . It required its own zero. An
altogether new reference was used:
namely, 1 milliwatt of power across
600 ohms, using a frequency of
1000 Hz.
Since this was a meter which measured the "volume of audio," the
unit of measurement became known
as a "VOLUME UNIT," or VU. If a
1000 -Hz sine wave is measured by
a VU meter (or VI, for Volume Indicator), the RMS value of the voltage is the result. A 1000 -Hz sine wave with power of 1 milliwatt
across 600 ohms will measure 0 VU.
By Ohm's Law, we find that it
represents an RMS voltage of 0.775
volts (across 600 ohms):
P = E2/R = 0.7752/600 (watts) _
1/1000 (watts) = 1 mW.
About this time, it was decided,
for the sake of conformity, to redetermine the standard dB, and use
this same 1-mW base instead of
In order to distinguish between the two standards, the power
ratio using 1-mW base was designated a "dBm" (the "m" standing
for milliwatt). The old designation
of 0 dB has practically been eliminated, and the new reference of
0 dBm is almost universally used.
With a sine wave, then, VU and
dBm mean the same thing. However, dBm is used ONLY with sine wave signals, and NEVER with
audio.
When program audio is sent
through a circuit terminated in 600
ohms, the level can be read as a certain number of VU above or below
the standard 0 VU which has been
established. It has become more or
less standard practice for U. S.
radio stations to use +8 VU as the
standard for feeding telephone lines,
transmitter lines, etc. If a meter attenuator is inserted in the metering
circuit, and set for +8, then when
the meter peaks zero, the VOLUME
UNIT of that peak is in reality 8 VOLUME UNrrs above the standard reference. It is called "zero at +8," and
is, in reality, +8 VU. If a 1000 -Hz
sinewave is used, a VU is the same
size as a dB, and 0 VU and 0 dBm
are then the exact same level.
Actually, the restrictions (600
ohms, 1000 -Hz, etc.) are for the VU
and not the dBm. The dBm is a unit
of finite audio power, when using
sine -wave signals, which has as its
zero reference a power of 1 mW.
This can be across any impedance
whatsoever. One mW across a 4 -ohm
speaker coil or 1 mW across a 1/2-meg
grid resistor would each represent
0 dBm, although the voltages would
be widely different. Thus, the meter
would have to be calibrated in volts,
and the value of the power in dBm
calculated.
6 mWs.
Check No. 55 on Reader Service Card
54
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Willi
Studer thought you'd
like
low noise
low distortion 30-20 kHz at 3% i.p.s. and
a dynamic range of over 60 db
plus beautiful styling and
a professional standard,
breathtaking finish
so he built the 77
REVOX CORP.,
Mineola Ave.,
Roslyn Heights, N. Y. 11577
Telephone: (516) 484-4650.
In Canada contact TRI -TEL Associates Ltd.
Name
212
Keeps Recording into the Future
Address
Please send full deta is of the Studer-Revox 77.
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than sine -wave peaks for the same
VU meter reading." In fact, this
The VU on the other hand is tied
to a 600 -ohm terminated circuit because it uses a specific meter calibrated in VU (and thus, in a sense,
in power units) Actually, it is a voltmeter and will read the actual
voltage across the two points being
measured, but it assumes that the
impedance is 600 ohms when it does
statement is made frequently, but
without a picture in the person's
mind of what the real significance
is. It has also been said that there is
a difference of about 7 dB between
the two. Some say 10 dB, others
.
from 8 to 14 dB.) In order to illustrate this, an oscilloscope was set up
and pictures taken of the phenomenon under discussion.
No hard fast rule can be laid
down with regard to the real amplitude of audio peaks, because so
much depends upon the tone being
used, the vowel sounds, and the
particular pitch or quality of a musical note. Again, it is a matter of
averages. The photographs shown
here were taken with slight time exposures, less than a second, so that
there was an average of many tones
and syllables in each case. First, a
tone was sent through some equipment so that the VU meter read zero
at +8 VU. (This was also +8 dBm.)
The signal was fed into an oscilloscope, and the vertical gain adjusted
to obtain 2 cms of deflection. The
trace was photographed. A card, cut
to size, was then placed over the
oscilloscope screen so that the sine wave was completely covered. (In
this way, the next trace would not
obliterate the sinewave on the photo -
.
Fig.
.
(
the mathematics necessary and
reads out in terms of power (VU)
Even a meter which is calibrated in
dBm, and reads dBm directly, must
be used in a circuit with the impedance specified for the particular
meter. This is usually 600 ohms, but
does not have to be. In the case of
the VU meter, the impedance must
always be 600 ohms because that is
one of the specifications of the meter.
Thus, if a 600 -ohm dBm meter is
compared with a VU meter, and
sine waves are used, they will both
indicate the same.
Now a VU meter is so constructed
and damped that a sharp audio peak
cannot possibly be followed by the
meter. In fact, the meter presents a
sort of average of the audio, and the
"peak" that is seen and read on
the meter is only a fraction of the
actual voltage that was present to
produce the peak. This produces a
very important concept.
The statement has often been
made that "audio peaks are higher
graph, since a double exposure was
planned.)
Audio was then picked up from
the radio station, and an audio man
"rode gain" as he would have for a
program, aiming for a good ZERO
LEVEL (at +8, of course) The resulting trace was then double -exposed on top of the previously photographed sinewave. Only that portion
of the audio which was greater in
amplitude than the sinewave was
visible because of the card covering
the center portion of the oscilloscope. The spectacular result is
shown in Fig. 2A.
The 2 ems represents the reference level, and it can be seen that.
audio peaks cover at least a 5.6 -cm
range, representing a voltage 2.8
times the voltage of the reference
signal. This translates into 9 dB.
Figure 2B is another picture of
the same thing, but with different
program material. The ratio here
calculates to 10.8 dB. Occasionally
du:ing this experiment, peaks as
high as 14 dB above reference 0
were noted, although not caught or
a photo. This average value of 10
dB or so is what is termed HEAD-
1-Typical audio equipment block diagram shows test levels.
ROOM.
Thus, as a VU meter is read showing a tone at 0 VU, and then program audio peaks hit this same 0
Fig.
2-Double exposures show relationship
between sine wave and audio levels.
STUDIO CONSOLE
-
PGM
LEVEL
-60VU
-20VU
-56VÚ
_16VU
-38VU
8VU
18VU
MIC. OR
TEST
+8VU
DB
SIG
x
o
A.G.0
CHAN
18 D B M
TEST
-s0.. -lo
SIG
LEVEL
DBM
DBM
-46 _ -6
DBM
DBM
-28 _
18
DBM
DBM
L
i wrr
eiliiffi
280 BM
I
.
AUDIO
56
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AmericanRadioHistory.Com
y
NOVEMBER 196,9
VU, it must be remembered that the
peaks that cause the 0 hits are in
reality approximately 10 dB higher
in voltage, or approximately 31/2
times the voltage of the steady-state
tone that also reads 0 VU.
In checking out the studio, ewe are
primarily interested in determining
the distortion produced by the system, its overall frequency response,
and how far below program level is
the basic noise of the system. The
first question which arises for all
three tests is to determine the level
at which the tests are to be made.
Since the tests will be made using a
steady-state tone, we realize immediately that we will not be checking
out the system properly unless we
do something about checking at the
peak -to -peak amplitude that we
have found audio peaks actually run.
Since we say that there is about
a 10 -dB discrepancy, it has become
customary to run all studio checks
at a level which is 10 -dB higher than
normal program levels. This means
+ 28 dBm where a normal program
level would be + 18 dBm, or +18
dBm where normal program level is
+8 dBm, or -50 dBm where normal program level (microphone)
would be -60 dBm, etc.
The actual test lineup of amplifiers and equipment will vary from
station to station, but let us use
Fig. 3-Photographs show sine-wave level increased to closely resemble audio peaks.
Fig. 1 as an example, showing a pre amp for the mike, followed, after
suitable attenuators for control, by
a booster amplifier, and finally a line
amplifier for the studio output. This
wouid then go through an AGC amplifier, and a line amplifier for transmission to the telephone company
or the transmitter.
Assume for purposes of discussion
that average mike levels is -60 VU
(this also happens to be a good
standard to use). Thus, to duplicate
program meter readings, a tone at
the input to the preamp, or -60
dBm, would be used. (0 dBm is produced by 0.775 volts across 600
ohms, or by 0.387 volts across 150
ohms. A signal 60 dB less than this
would be .000387 volts across 150
ohms.)
Set up a signal generator at 400
Hz and -60 dBm at 150 ohms output impedance, which is the usual
input impedance, and leaving the
master volume control where it is
usually used by the audio man; set
the microphone attenuator so that
the output of the studio is normal
program level, as shown on the VU
meter. (This is usually 0 at 8 VU.)
This is then metered after the final
channel amplifier and either before
or after the final splitting pad. (See
Fig. 2.) Let us look at it BEFORE
the final 10 -dB pad which normally
Fig. 4-Photograph (A) shows noise level at
55 -dB below normal program level. (B) Illustrates distortion at same level.
feeds the phone line, monitors, etc.
At this point, then, the level will be
plus 18 dBm. (After padding, the
normal +8 will appear for transmission over the line.)
Now comes the big moment! Increase the signal generator output
by 10 dB (to -50 dBm). This is to
make the sine -wave peaks more
closely resemble the actual audio
peaks that are normally used
through these circuits. See Fig. 3.
The needle of the VU meter in
the studio console will "wham"
against the pin, but have no fears or
misgivings. Do NOT change the attenuator or remove the meter from
the circuit. I have been doing this at
regular intervals for several years
now, and although I had strange
feelings the first few times, I soon
found that the meter is built to withstand this mistreatment. In fact, it
can withstand this level continuously for hours. The output level at
our measuring point is now +28
dBm. All studio tests are made at
this level.
It is not intended in this article
to describe methods of making studio or transmitter proof of performance tests, but rather to point out
some interesting traps and phenomena that have been observed
during several years of making these
proofs at regular inervals.
Fig. 5-(A) Distortion signal from Fig. 4B. (B)
Test frequency. (C) After a 40 -dB pad was
inserted.
IB)
AUDIO
57
NOVEMBER 1968
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To make noise measurements, the
reference level is taken at the +28
dBm point. Using this as reference,
the line is terminated at the input
jack field, and using a Noise and
Distortion Analyzer, the noise level
is determined. If everything is working properly, the preamp will be the
determining factor in the noise level.
To pass studio specifications, the
noise should be 65 dB below the
reference of +28 dBm. (This, of
course, converts to -37 dBm.) It
also means that the noise is 55 dB
below normal program level. Fig. 4A
shows the nature of the noise that is
present at this low level. (In this
particular case, the noise measured
72 dB below reference.) The overall
patterns shows some semblance of
120 Hz. The fine peaks, of course,
are a random noise caused within
the preamp's first stage and/or the
input transformer.
In making distortion measurements, again the +28 dBm level is
used as a reference, and the distortion analyzer removes the original
signal (400 Hz, for example); what
is left is read as distortion. Fig. 4B
shows this distortion. In this case,
it measures 0.9%. The basic configuration is 180 Hz.
There is something interesting
about this measurement of the distortion. Since it was difficult to understand where a 180 -Hz signal
could be originating in the studio
audio equipment, I suspected that it
might be coming from the signal
generator itself. This indeed proved
to be the case. The 180-Hz signal is
apparently entering the system
someplace in the output transformer
of the generator. There is a calibrated ladder attenuator preceding
the output transformer. It was found
that by inserting a 40-dB pad between the generator and the audio
jack field, and then increasing the
signal to the output transformer by
40 dB by means of the ladder attenuator, it became possible to attenuate the 180 -Hz signal, while keeping
the signal strength of the signal the
same, as far as the studio was concerned. Fig. 5A shows the distortion
signal again, as shown in the last
photograph. Fig. 5B represents the
frequency that was used (400 Hz).
Fig. 5C (to the same scale as Fig.
5A) shows the result after the 40 58
dB pad was inserted. The signal reference was the same, but the distortion now measured only 0.15% (a
decrease of 15 dB). The distortion
consists mainly now of third harmonic of 400 Hz, or 1200 Hz. Thus,
the studio was really cleaner than
the tests at first seemed to indicate
-an interesting situation!
There are one or two interesting
points that should be brought out
when proofs are made through both
the studio and the transmitter.
Again, the matter of the level which
is used is a matter of importance. If
the level of the signal into the studio is decreased to the program level
of +8 dBm and sent to the transmitter, it will be found that the
modulation of the transmitter will
be about 45%, or approximately 7
dB below 100%. The transmitter is
a "peak -sensitive" device, and 100%
modulation is determined by the
actual peaks. Thus, a similar level
sine wave (as measured on a meter)
would be about 7 dB lower on peaks.
Obviously, the test level must be
brought up to 100% modulation.
The question arises as to where the
level should be brought up to produce 100% modulation. The limiter
at the transmitter has been disabled.
Let us see what would happen if the
level were to be brought up by
means of the amplifier in the limiter.
Let us assume, for example, that
our studio barely made its noise
specification of 65 dB below reference +28 dBm. Since we are now
using a signal of 10 dB lower than
this, or + 18 dBm at our measuring
point (+8 dBm at the input to the
telephone line to the transmitter),
the noise would now appear to be
only 55 dB below this new reference.
If the gain of the amplifier at the
transmitter is now raised to produce
the 100% modulation, both signal
and noise from the studio are raised,
and the relationship, or 55 dB, remains the same.
Let us suppose further that the
transmitter itself (FM) also just
barely makes its specification of 60
dB below reference 100% modulation. The resulting overall noise
through the entire system would
then be about 531/2 to 54 dB below
100% modulation, and this would
be far from the FCC specification
of 60.
Even if two identical signals of
-60 were added, the sum would be
only -56 dB. (I know the books say
it should be -57, but I have never
found this to be the case in actual
practice.) Similarly, -63 plus -60
equals about -581/2, etc. Finally,
when one noise signal is about 6 dB
or farther from the other one, there
is no apparent addition; (i.e., 66 plus
60, or 68 plus 62, etc.)
This then gives a clue as to where
the signal should be raised to produce the 100% modulation. With
the generator in the studio set for
-60 dBm, and no controls touched
at the transmitter, except for disabling the limiting action of the
limiter, the modulation of the transmitter should be brought up to 100%
by increasing the signal going into
the preamp. It will be found that this
increase is usually in the nature of
7 dB (achieved by adjustment of the
ladder attenuator on the signal generator) so that the studio signal-tonoise ratio in the extreme case mentioned above would become about
62 dB below the reference studio
output. This -62 added to -60, although still not passing specification, would be about -58 dB.
This shows that a better than
minimum noise measurement must
be met in the studio and transmitter
in order to pass the overall specifications.
This level of signal then is used
throughout the overall tests through
studio and transmitter. The 40 -dB
pad is again used for the distortion
measurements only. During the frequency-response test, the signal is
increased or decreased at the input
to the studio for each frequency to
allow for the pre -emphasis at the
transmitter for various frequencies.
Thus, we see that certain precautions must be taken when making
tests of audio equipment. HEADROOM
must be allowed for and taken into
consideration. The terminology VU,
DBM, etc., must be carefully understood so that there is unformity of
thought and expression during tests.
All in all, it is a very intriguing subject, and one in which some careful
study and consideration will pay
dividends in better audio and
smoother operation, and greater
satisfaction for the operating perÆ
sonnel.
.
AUDIO
NOVEMBER 1968
The
Goosebumper
A very strange and wonderful thing happens when you turn on a Harman-Kardon
Five Twenty stereo receiver. If the program material is right and the rest of your
system is up -to -snuff, you'll get goose bumps.
No fooling. Goosebumps.
It's kind of like when you're at a concert and the music wells up around you
and you get that marvelous shiver of excitement-that feeling that every musician is playing just for you.
The reason our Five Twenty sounds the
way it sounds is wideband response.
Many manufacturers restrict their amplifiers so that they do not go below 20 Hz
or above 20,000 Hz.
We don't.
harman
We build our amplifiers so they go well
beyond 20 and 20,000 Hz. The result is a
cleanness and openness in our sound that
you not only hear, but actually feel. True,
it takes a lot more time and money to
engineer a product with wideband response. You have to use a highly regulated power supply and every component
must be rock -stable. But we think it's
worth it.
How else could we have cornered the
market on goosebumps?
Hear the Five Twenty soon. Compare it
with competitive receivers. We're sure
you'll hear and feel the difference.
For more information write HarmanKardon, Inc., 55 Ames Court, Plainview,
N.Y. 11803, Box # A-11
kardon
We want you to hear more music.
Check No. 59 on Reader Service Card
AUDIO
NOVEMBER 1968
59
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Equipment
Profiles
The application of inverse feedback
to amplifiers has brought them to near
perfection in terms of frequency re-
Erath Models LWE-I and LWE-VI
Speaker Systems
Pioneer Model SX-1500T
AM/FM Stereo Receiver
Viking Model 433 Stereo Tape Deck
H. H. Scott Model LT -112B-1
FM Stereo Tuner Kit
Erath Models LWE-I and
LWE-VI Speaker Systems
MANUFACTURER'S SPECIFICATIONSLWE-I: One 15" woofer, one 6" midrange cone, one 5" horn tweeter. Nominal Impedance: 4 ohms. Freq. Resp.: (±5
dB) 22-20,000 Hz. Controls: High frequency, mid -frequency, room gain. Dimensions: 25" H, 17" W, 12" D. Weight:
61 lbs. Price: $250.00, oiled walnut;
$225.00, birch; $175.00, "instant kit."
LWE-VI: One 8" woofer, one 3h/2"
tweeter. Nominal Impedance: 8 ohms.
Freq. Resp.: (±5 dB) 29-15,000 Hz. Controls: High Frequency. Dimensions: 19"
W, 10" H, 9" D. Weight: 46 lbs. Price:
$100.00, oiled walnut; $90.00, birch;
$75.00, "instant kit."
-
Fig. 1
The LWE-I three -speaker system
(top) and the smaller LWE-VI two -speaker
system, both of which utilize
feedback system.
a
voltage
sponse and distortion. Therefore it is
not unnatural to consider the use of
feedback to improve a speaker system's performance. In fact, we heard
some excellent prototypes that used the
feedback principle many years ago.
But none ever succeeded in production.
Erath has!
Whereas others attempted to pick
up the radiated sound from the speaker
by means of an additional transducera microphone or an additional winding on the speaker voice coil-Erath
speaker systems utilize an electronic
network to generate their own error
voltages when the speaker does not follow the amplifier output, thus compensating for any speaker deficiencies.
Primarily, its purpose is to extend,
electronically, the speaker's bass response, as well as to improve transient
response. And whereas earlier efforts
in this direction required that one
purchase a complete system, from amplifiers to cabinet, the Erath speaker
systems, which externally, look quite
conventional, can be used with any
high -quality component amplifier or
receiver (the amplifier must have at
least 20 dB of feedback, which most
good units do).
Two of the company's four models
are examined here: Model VI, the
smallest in the line (19 -in. x 10 -in. x
9 -in.) features an 8 -in. woofer and a
31/2 -in. mid - range / high - frequency
speaker: Model I (25 -in. x 17 -in. x
12 -in.) is once removed from the biggest Erath system. It incorporates a
15 -in. woofer, 6-in. mid -range, and a
5 -in. horn tweeter. At $100.00 ($75.00
for an "Instant Kit") and $250.00
($175.00 for an "Instant Kit"), respectively, they would appear to hold
promise of being the most popular in
the line.
All the systems have air -tight enclosures, similar to acoustic suspension
systems, but efficiency is higher than
many sealed enclosure systems. Clean
20 watts/channel amplifiers should be
satisfactory for normal use. The VI has
a power -handling ability for program
material of 25 watts (peak power may
be much higher, of course), while the
bigger Model I can handle 50 watts.
Whereas the Model VI has a high frequency control, the Model I (and
the other two models in the Erath line)
adds a "Room Gain" control, as well as
a mid -frequency control. The unusual
"Room Gain" control is actually an
60
electronic broadband filter that works
in conjunction with the speaker's feedback circuit to minimize frequencies at
which a room resonates. Thus, its purpose is to influence frequency and
amplitude in order to compensate for
room acoustic deficiencies.
Before we discuss the performance
capabilities of this remarkably different speaker system, however, let us
examine the theory behind it and the
speaker construction more closely.
A cross-section view of any Erath
speaker system would reveal a typical closed -box -enclosure construction,
with lots of absorbent material-plus a
"black box" and crossover networks.
It's the black box that's intriguing, of
course. This is the novel feedback network, which includes some reactive
elements. It develops a voltage which is
fed back to the same point in the user's
amplifier at which the usual negative
voltage feedback is introduced, resulting in the arrangement of Fig. 2. This
circuit can thus eliminate boominess
-
Fig. 2 The drawing below shows how
feedback voltage is derived when an Erath
loudspeaker/feedback network is connected to an amplifier.
of a woofer, and with proper choice of
the reactive elements in the network,
extend the bass response of a system
appreciably.
The speaker has a 6 -terminal male
plug by which connections to the amplifier are made. Two of the leads carry
the voice -coil current to the speaker,
and two carry the "feedback" signal to
the amplifier from the speaker. The
other two may be used as tiepoints
for additional resistors which may be
needed to adapt the network to the
particular amplifier or receiver being
used. At the amplifier, the female output plug is connected to the speaker
terminals in the usual fashion, and two
additional connections are made inter -
AUDIO
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NOVEMBER 1968
MODELS 585SAV
AND 585SBV
f.
.
NISPHERE
UNIDIRECTIONAL MICROPHONES
The popular, "ball -type" Shure Unisphere A series of microphones are the kind of public-address
system problem -solvers that have made them run -away favorites with sound men, speakers, and
performers from coast -to -coast. And, they are budget -priced in the bargain! They have the
superb, world-renowned uniform cardioid pickup pattern that has made Shure Unidynes the
industry standard for controlling feedback. Their tone is uniquely suited to natural reproduction
of the entire voice range. They are unexcelled for controlling reverberant "boom" in partially
filled halls. In addition, ball -shaped filter assemblies control windnoise in outdoor applications.
-
The new models 585SAV and 585SBV are among the most ingenious and versatile of microphones
in that they feature a built-in volume control
they are ideal where amplifier controls are inaccessible, or where the speaker or singer wants to control his own volume for dramatic effects.
Instantly interchangeable from stand to hand. Whatever the problem, the Unisphere A microphones can help solve it ... economically!
SHURE BROTHERS, INC.
/
UNISPHERE A
Model 585SA High
Impedance; 585SB
Low Impedance. Budget priced for use in
low -budget systems. List Prices:
Model 585SA $65.00; Model 585SB $58.00
UNISPHERE A
WITH VOLUME CONTROL
Model 585SAV High Impedance; 585SBV
Low Impedance. Volume control versions
of the Unisphere A. List prices for either
model: $72.50
222 Hartrey Ave., Evanston, Illinois 60204
C 1968 SHURE BROTHERS,
INC.
Check No. 61 on Reader Service Card
AUDIO
NOVEMBER 1968
61
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Equipment Profiles (continued)
Fig.
the
3-A
side cutout on
LWE
shows the
I
"black box" feedback network in the right corner.
Fig. 4
Fig. 3
- The
LWE-VI
is
shown atop the LWE-I,
both with front grille
cloths
removed.
The
LWE-I pictured here is the
company's "Instant Kit,"
which has its controls
(room gain, mid -range,
high frequency) on the
front panel in the event a
user wishes to build the
unit into the wall.
nally by means of cleverly designed
"Q -ball" connectors.
This may sound like a difficult operation for the average purchaser, but
Erath has made it quite simple. A complete line of adapters has been worked
out by Erath engineers, and for $5.00
you obtain the one to match your amplifier or receiver. These simply clip
onto the designated points in the amplifier at the feedback junction, in
accordance with the instructions accompanying the adapter. Illustrations
of the proper connection points for
most popular amplifiers and receivers
make this quite simple to do.
The units we tested were used with
a Sony TA -1120 amplifier, and we also
obtained the adapter for the Acoustic
Research amplifier. The Sony had two
resistors and a choke, while the AR
had no external components whatever
-simply the cable plug with four
leads coming out from it-two for the
speaker terminals on the amplifier, and
two to be clipped on resistors inside
the amplifier.
Performance
Listening to the small, though not
subminiature Erath VI reproducing a
variety of source material, we were impressed by two facts: (1) For a small,
two-way system, it exhibited smooth
overall response, and (2) bass response
was exceptionally good.
Concerning the latter, the immediate
effect was very much like hearing an
unexpected half -octave more of clean
bass, not to mention the outstanding
crispness of the low end in general.
Our optimum preamp control settings
within the environs of its enclosure.
Thus it produces a wide, open sound;
a transparency that is most appealing.
The Model I has a control labeled
"room gain" which compensates for
different sizes of listening rooms. One
of our listening rooms is not large,
being about 3200 cu. ft., but with an
additional 1400 cu. ft. opening off
the kitchen and a short hallway. The
main portion of the room is an approximately symmetrical "L" shape. It
should develop resonances at about 26,
44, 61, and 77 Hz, thus coloring any
sound reproduction to some extent.
The effect of the "room gain" control
is to use these resonances-since they
influence the radiation resistance of the
speakers-to control the amplifier and
to make it perform in a way which will
minimize the resonances. This is, to
our ears, just what happens. Low frequency resonances due to the room
dimensions cannot be damped out by
the usual acoustical materials but the
LWE speaker can provide a controlling signal for the amplifier so that the
final result is a great reduction in resonance effects.
By measurement, the response in the
air rose slightly at 40 Hz, t`ben began
to fall off in accordance with the roll off network in the Sony amplifier-a
bridge -T arrangement which starts to
cut off about 60 Hz, and is down 6 dB
it-
Fig.
4
at all. Mid -range and treble response
were non -peaky and well balanced,
with sufficient high -frequency dispersion for small -to -medium -size rooms.
Judging the merits of the Model VI as
a small bookshelf speaker system, we
consider it to be among the hest we've
heard to date. It appears to meet the
manufacturer's specification claims,
and its low -frequency performance
rivals that of many larger and more
expensive speaker systems.
Erath's Model I, a large bookshelf size or medium floor -standing speaker
system (a $12.00 walnut base is available for the latter purpose), sounds
better and better as one listens to it
(them) for a substantial period of time.
This is characteristic of truly fine
speaker systems. With nothing flashy
to deceive a person on an initial hearing-certain frequencies favored, for
example-one cannot quickly focus on
an outstanding attribute. The Erath I
is such a speaker system. It does not
noticeably favor any part of the frequency spectrum, and the frequency
range is extremely wide and marvelously balanced. The upshot of this is a
speaker system whose acoustic reproduction does not appear to be entirely
5-Erath's cleverly designed adapter
clips onto the feedback junction point in
an amplifier.
Fig.
for this speaker (s) was bass tone controls slightly on the minus (-) side,
treble controls normal. There was a
whisper of "tightness" while reproducing low frequencies, but no tubbiness
at
10 Hz.
There is no doubt that a three-way,
three -speaker system, which includes
a 15 -in. woofer, has the capability of
producing fine sound. But since the
Model I goes beyond what is expected
of it, we can only attribute this to the
feedback network developed and applied by the L. W. Erath Company.
Without equivocation, the Model I exhibits immaculate low and very -low
bass response. We've never heard better in this size enclosure. Mid -range
and high frequencies are also excellent,
with the latter having the characteristic brilliance of a horn tweeter.
Clearly, speaker system designs are
not nearly as traditional as one might
think they are. Proof of this is the
new design path taken by Erath in developing a frequency -selective feedback system that automatically makes
a high -quality amplifier feed a corrective voltage to the speaker when it fails
to follow the amplifier's output faithfully. More importantly, both LWE
feedback speaker systems examined
here proved to be excellent performers
-especially in the areas of frequency
response and transient response.
Check No. 60 on Reader Service Card
AUDIO
62
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NOVEMBER 1968
The Sony Side of the Street
(it's any place they're showing the new 6060 receiver).
The Sony96060 receiver is the brightest thing that's hapture ratio, 1.5 dB. Spurious signal rejection, 90 dB. Abundant
pened to stereo hi-fi in a long while. A superb performer on
control facilities: automatic stereo reception; zero -center
FM stereo; FM and AM broadcasts; records and tapes. It will
tuning meter; front panel headphone jack; switches for tape
brighten up the music in your liife.
monitoring, muting, speaker selection, tape or Aux, input,
Here's what Sony built_Ampìifier 110watts 1HFpower into
loudness the works.
8 ohms. Distortion less than 0.2% at rated output. The tunerAt $399.50 (suggested list) the 6060 outshines receivers
sensitivity 1.8uV. Exclusive solid-state i.f. filters never need
costing up to $500. Get a Sony disposition.
alignment, provide razor-sharp selectivity, 80 d B; superb capSony Corporation ofAmerica,47-47 Van Dam St. L.I.C. N.Y. 11101
-
AUDIO
NOVEMBER
196E
-
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63
Equipment Profiles (continued)
Pioneer Model
SX-1500T
AM/FM Stereo Receiver
MANUFACTURER'S SPECIFICATIONSFM Section: IHF Sensitivity: 1.7 /t,V. Image
Rejection: 76 dB (@ 98 MHz). Signal -to Noise: 65 dB. Capture Ratio: 1 dB. Stereo
Separation: 37 dB (@ 1 kHz). AM Section: IHF Sensitivity: 20 /t.V. Image Rejection: 60 dB (@ 1 MHz). Amplifier Section:
Music Power (total): 170 watts @ 4 ohms.
140 watts @ 8 ohms. RMS Power (per
channel): 60 watts @ 4 ohms. 55 watts @
8 ohms. Harmonic Distortion: Less than
0.5°/o at rated output (1 kHz). Frequency
Response: 20 Hz to 70 kHz ±1 dB. Power
Bandwidth: 20 Hz to 70 kHz. Hum and
Noise: Tape Head: better than 75 dB. Mag.
In.: better than 80 dB. Aux. In: better
than 90 dB. Damping Factor: 25 @ 8
ohms, 1 kHz. Tone Controls: Bass +12
dB, -14 dB @ 50 Hz; Treble +10 dB,
-11.5 dB @ 10 kHz. Filter Action: Low:
dB @ 50 Hz. High: -10 dB @ 10
kHz. General: Dimensions: 167/6 in. W x
51/2 in. H x 13/4 in. D. Price: $360.00 (Including Metal Cover and Walnut -Finish
side panels).
-6
Among the better, high-powered
crop of receivers offered to the stereo
component purchaser this year is the
Pioneer Model SX-1500T. It is
equipped with just about every control
one might expect to find on separate
amplifiers or preamplifiers.
The unit is well -styled, sporting a
light gold and black anodized heavy
front panel, a walnut -colored metal
cover and two walnut -finished side
panels, all of which combine to give the
unit a trim, modern look. The upper
portion of the panel contains the tuning dial area, including the usual stereo
indicator light and a peak -reading tuning meter. A 0-100 logging scale serves
to divide the upper FM scale from the
AM scale beneath it. Calibration markings are not pinpointed, however
(while numerals appear for every 2
MHz of FM dial spread, no definitive
marking point for each numeral is
present). One can use the logging scale,
of course.
To the right of the tuning dial area
are the flywheel -mounted tuning knob
(not quite velvet smooth, but satisfactory nonetheless) and the main
function selector switch. Besides the
expected positions of this switch, such
as
AM, FM MONO, FM AUTOMATIC STEREO,
PHONO, and AUX, there are two very
-
tape -head positions
welcome ones
equalized for either 71/2 ips or 3% ips
for direct playback from a tape transport. Few receivers, let alone amplifiers
or preamplifiers, provide this option
and, we might add, both of these positions do offer correctly equalized
(NAB) response within 1 dB from 30
Hz to 18,000 Hz.
The lower portion of the panel, starting at the left, contains a speaker selector switch (main, extra, both, and
speakers "off") which, in its counterclockwise position, turns off all power
to the unit. Bass and treble controls are
of the dual concentric type, with clutch
action for left and right channels.
These are followed by conventional
balance and volume controls. Secondary functions are controlled by means
of six small, elegant lever switches.
These functions include loudness contour, low filter, high filter, muting,
AFC, and a "Phono -Phono 2" switch to
Fig. 2 (upper)-Rear panel layout of the
Receiver.
-
Fig. 3 (lower) The top -of -the -chassis
view shows the clean construction of
the Pioneer unit.
enable the user to have, say, a turntable and a record changer connected
to the equipment simuli:aneously.
Again, this last is a feature not normally found on all -in -one receivers.
The usual phono jack and a rotary six position "mode & tape monitor" switch
completes the layout of the front panel.
Why six positions for "tape monitoring"? To enable you to either listen to
left, right, or stereo channels through
both speakers or to monitor left, right,
or both channels from a "three headed" tape recorder. Figure 1 illustrates the front of this receiver.
Besides the usual input and recorder output jacks, the rear panel is
equipped with two a.c. convenience
outlets, the necessary antenna and
ground terminals, the fuse post (as well
as the voltage selector in the case of
the SX-1500TF model, which features
selectable voltages from 110 V to
240 V) and a loop -stick AM antenna,
movable for best AM reception.
Speaker connection is unique. There
are four polarized two -prong receptacles, one for main speaker connection
and one for extra speaker connection.
Four two -prong plugs are supplied
separately, to which speaker leads can
be connected under the heads of screws
in the usual fashion. These plugs are
then inserted in the appropriate
sockets. This has the advantage that
once you have properly wired the
speakers to the plugs for correct phasing, speaker systems may be disconnected at any future time (for moving,
cleaning, etc.) and, when reconnected,
phasing will always be correct, thanks
to the polarized plug and jack combinations.
The rear panel layout is shown in
Fig. 2, while Fig. 3 is a close-up view
of the chassis surface, showing the
separate AM and FM front ends, as
well as three of the eight P.C. boards
which go to make up this unit. The
four power output transistors are
mounted on large, heavy heat sinks to
which are affixed heat-sensitive thermistors for bias stabilization of the output circuits. Electronic switching in the
power supply further protects the output transistors from inadvertent shorting of speaker leads and other excessive
current loads. In all,this husky receiver
contains 4 integrated circuits (IC's),
all in the FM i.f. strip, 1 FET (in the
FM front end or r.f. section), 39 transistors and 29 diodes.
Performance
Measured performance was generally excellent, adhering quite closely
to published specifications. Referring to
64
AUDIO
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NOVEMBER 1968
All turntables
are not
created equal.
(This is a public service message from Marantz.)
There are two ways to build a turntable. The ordinary way.
And the Marantz straight-line tracking way.
Straight-line tracking makes a home turntable system
reproduce the sound on a phonograph record exactly as it
was originally etched by the studio cutting head. And only
Marantz has straight-line tracking. Straight-line tracking
keeps the tone -arm precisely tangent to the groovesnot sloshing around in them.
That's why it is the only known
way to give you absolutely uniform
stereo separation and frequency
response from the outermost
groove to tre innermost (where
distortion is greatest). In addition,
straight-line tracking eliminates
tracking error distortion, uneven
stylus wear, and skating force.
Another Marantz feature, positive cueing control, ends
accidental record scratching forever. One simple control
knob lets you set the stylus in any groove you desire.
The Marantz Model SLT-12U turntable is equipped with a
universal pick-up head which is adaptable to a broad selection of popular cartridges. No wonder-feature for featureit is the ideal instrument to enable you to enjoy perfect
stereo sound in your homeexactly as heard in the finest
recording studios. And best of all,
it is priced at just $295.
There is so much that goes into
making a Marantz a Marantz, that
your local franchised Marantz
dealer will be pleased to give you
a demonstration. Then let your
ears make up your mind.
m s3zeiserf
Designed to be number one in performance... not sales.
OMARANTZ CO.. INC., 1968 MARANTZ IS A SUBSIDIARY OF SUPERSCOPE, INC PO BOX 99C
AUDIO
NOVEMBER 1968
SUN VALLEY, CALIFORNIA 91352
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SENO FOR FREE CATALOG.
65
Equipment Profiles (continued)
Full Limiting
2
NV\
m 0
72.
10
I-
20
o.
30
IHF
Sens. (1.7i.V
Ó 40
>
~
W
With
L- Only
Applied
68dB
0.6%
30dB S/N
L Out
o
THD Max S/N
)
10
(1.5 NV )
Rés'¡".....................
wae4a/
50
Noise
&
to
J
Distortion
m 20
60
U
w
Residual Noise
70
0
w 80
R
Out With L Onl Y Applied
Pp led
30
/
40
0.2
20
100 200
10.0
1.0
100
ANTENNA INPUT (MICROVOLTS)
Fig.
FREQUENCY ('HERTZ)
4-FM performance characteristics of the SX-1500T.
6-IM and THD characteristics. Note
minimal distortion at low power output,
indicating virtual absence of crossover
distortion.
AL
10k 20k
1k
Fig.
5-Stereo separation characteristics of the Pioneer receiver.
Fig.
Fig.
60-
VO2.5
THO 81M -
pQZ2.0
QO
O
J¢Ñ
ÓZ
I
one channel
8 -ohm load, both
ñ
1.0
Reference 55W at 1%
+10
m
30-
v
w
275 W
27
-17Hz
70 kHz
7 20-
0.5
........................................
00
10
20
30
POWER OUTPUT
O
THD
40
50
and HI and LO filter
characteristics.
- 50-
3 40-
channels driven
1.5
8-Tone-control
Fig.
+20
3.0
70z
7-Power-bandwidth curve shows
excellent performance.
-+
0 Lo
-10
Hi
Filter»;..'
..
Filter
-20
10-
s
s
60
(WATTS)
Fig. 4, you can see that FM IHF sensitivity was exactly 1.7 ß,1,V, as specified.
Ultimate S/N ratio was 68 dB in FM,
as compared with a claim of 65 dB.
Total harmonic distortion at 75 -kHz
deviation was a mere 0.6%. In stereo
FM, for equivalent modulation, distortion measured 0.9%, after eliminating
residual 38 kHz and its harmonics.
These residual signals were down some
36 dB at the tape output, a figure that
could stand some improvement. The
use of IC's in the IF strip provides
excellent limiting (within 1 dB of full
output at only 2 jt,V), while the FET
in the r.f. section accounts for the very
excellent image rejection observed as
well as the almost complete absence of
measurable cross -modulation. As for
stereo FM performance, switching
from mono to stereo was accomplished
with no accompanying clicks or noise
bursts. Stereo separation, as shown in
Fig. 5, was 37 dB at 1 kHz and no
worse than 20 dB at any frequency
from 50 Hz to 10 kHz.
As for audio performance, we measured 52 watts rms per channel at a
THD of 0.5%, only a fraction short of
the 55 watts spec. In any event, we
were able to pump 55 watts out per
channel at a total distortion of only
20
10
100
1k
10k
100k
FREQUENCY (HERTZ)
1%, as shown in Fig. 6. IM distortion
was 1% for 50 watts rms per channel
output, and only 2% at a whopping
60 watts out.
The engineers at Pioneer must belong to the "wide-band" response
school for, although we suspected that
the Power Bandwidth published specification might be a misprint, it actually
does extend from 17 Hz (they claim
only 20 Hz) to 70 kHz! You'll never
lack for "highs" with this one! Power
Bandwidth is plotted in Fig. 7.
Tone control range is as shown in
Fig. 8. Also in the same figure are the
"cut" characteristics of the low- and
high -filters. These filters have pretty
much the same slope as the tone controls (about 6 dB/octave) even though
the crossover points are a bit lower and
higher, respectively. Had they been designed with a 12 dB/octave slope, they
might have proved more useful. With
tone controls set for flat response and
no filters in the circuit, one can sense
the smoothness of response and excellent transient attack characteristics of
this receiver. We borrowed an extra
pair of low -efficiency, high -quality
bookshelf speakers (in addition to the
main pair) to see what 55 watts can
do, and we can report that this amount
66
100
10k
1k
FREQUENCY
of power was more than adequate for
driving four low -efficiency speakers.
The sound remained clean from the
lowest level to "3 o'clock" on the volume control.
With a sensitivity of 1.7'í,V on FM,
it goes without saying that we pulled
in just about every mono and stereo
station from "fringe" and locally. The
muting was effective between stations
and added no distortion on marginally
received signals. Level balance between
AM, FM, and Phono was very good,
but Tape Head inputs had a bit more
gain, so volume had to be lowered when
switching to this service. There is a
separation control on the rear panel
which has been factory preset and customers are warned not to change the
setting (so why make it accessible?),
but aside from this paradox, controls
handle well, are smooth to the touch
and very functionally arranged.
If you crave lots of power and don't
want to get involved with separate
preamp-amps and tuners, the Pioneer
SX-1500T AM/FM stereo receiver certainly has enough power and enough
true component features to make it
very worthy of consideration at its remarkably low price of $360.00.
Check No. 64 on Reader Service Card
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20k
(HERTZ)
-..
This beautiful four-headed monster
does away with amateurs.
O -12.e you've met up with- cu- monster
with four heads, you're done fcr. Your
amateur days are over. That's beeauae the
4 -track Solid -State stereo RS '79C S has
just about everything you need to dc
a professional job of taping.
Firit, there's 3 -speed Dull Capstan
drive. it ends audible flutter Lnd wow.
And tl: sound is all the better fcr it.
Four heads are better for sptnd to).
And tl_e Console-Aire delivers 3C -18,0C.0
cps and a signal-to-noise ratic cf more
than 52 db's. It all adds up to the greater
fidelity :he pros lister for.
Another great thing is coritir uons
Automatic Reverse. Records ar_d plays
back in both directions. It means no more
interruptions And you'll r ever have to
lip over a reel aga n. At a no point on the
:ape you can mani r.11y punch up
reverse, too. Of course, if 'ol: don't
want it to run on forever, use the
automatic shutoff.
Pause Controls anotaer nice feature.
It operates in forward and reverse, and
ocks down for ease editing
It gets better.
There's eadplone output for private
istening. Makes it Easier to record
sound -on -sound ar_d sound -with-sound.
If that sounds like a lot cf sound,
t should. You_ get á'0 -watt output through
:wo 7" oval speaker; with baffle boards.
There's riore tc come. L:ke two
t
200 PARK AJ=NUE NEW YORK L0017
For your nearest Panasonic de9ler, call C3C0t243=Oß55. In Coon., 853.3600. We pay tar the ca
*Suggested t3 price. Canadian price higher.
I.
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Dynamic Pencil Mikes with stands.
Connecting ccrds and other extras.
That's nog al. Ycu get 2 precision
VU meters, se -parate tone and volume
controls, lighted directional indicators,
and a 4 -place liital counter. Top this
with a smoked-grass dust cover,
and you're on 'our way.
After all, it's N.hat you'd expect
from the world's leading manufacturer
of tape recorders.
into any dealer's we perrrit to
So
carry Panasonic. We have a feeling :hat
once you come face-to-face with our
beautiful four -headed monster, you 11
lose your amateur standing forever.
(And for just 3:329.95.* )
p
Equipment Profiles (continued)
See Fig. 2.
Viking Model 433
4 -Track Stereo
Tape Deck
MANUFACTURER'S SPECIFICATIONSRecord/Playback Frequency Response: 40
to 18,000 Hz ±3 dB @ 7V2 ips, 40 to
12,000 Hz ±3d8 @ 33/4 ips, 50 to 6,000
Hz @ 1'/e ips. Signal -to -Noise Ratio: 54 dB
or better. Distortion: 1°/o THD at 1000 Hz.
Bias/Erase Oscillator: 80 kHz. Crosstalk
Rejection: 55 dB. Fast Forward/Rewind
Time: 70 sec. for 1200 ft. Reel Size: 7"
max. Wow and Flutter: Less than 0.2°/o @
7'/3 ips, 0.25°/o at 33/4 ips, 0.5°/o at Da ips.
Diemnsions: 153/4" W x 143/a" H x 83/4"
D (behind panel, 61/3"). Price: $369.95.
With walnut base, $389.95.
Viking's new Model 433 is an attractively styled, unusually versatile, medium-priced machine. It offers lots of
worthwhile features for the serious tape
sound -on -sound and echo,
recordist
among them. At the same time, it is
an impressive performer. The model
number "433" spells out what the recorder includes: four tracks, three hyperbolic tape heads, and three speeds.
(It also has three motors.) As distinguished from a tape recorder system,
the Viking deck does not incorporate
power amplifiers and/or speakers, of
course. Thus, it is not designed to be
used as a portable unit (though it could
be used for this purpose with the addition of portable amplifiers and speakers
such as Viking's Model 4400 speaker/
amplifier system).
The 433 deck, which is a gold and
black unit, can be purchased fór cabinet
or panel -cutout "custom" installation,
or with an oiled -walnut base. The
former includes mounting brackets.
An operator of the 433 tape deck is
likely to find the two level meters most
useful since they are illuminated when
in use, indicating the mode of operation at a glance. That is, while recording mono, only the proper level meter
is active, as an example. Equally helpful are Viking's mode indicators. These
are four indicators (two on each side
of a level meter) that light up "Play"
or "Record," with a green or red illu-
-
mination, respectively. A single multifunction selector switch is used to
choose the desired function which can
be observed on the mode indicators
(and the function read even at a 10 -ft.
distance)
There are separate playback level
controls and monitor controls which
vary their respective outputs (RCA
phono jacks at the rear) A monitoring
headphone jack (for 4 to 600 -ohm headphones) is also provided on the front
panel. The inputs have separate microphone and high-level controls so that
mixing of auxiliary sources wtih microphones can be accomplished by the
recorder electronics without an external mixer. The mikes plug into the front
via phone plugs, while the hi -level inputs come into the rear. Another feature is an echo switch which enables
some of the sound picked up by the
playback head to enter the recording
circuits. The record head precedes the
playback head in time by a few milliseconds, so we get some echo while
recording. On most recorders this requires cable patching at the rear plus
some sort of control to vary the amount
of echo. Here the amount of echo is
controlled by the "play" controls while
recording. The mode switch also includes transfer modes from left to right
and vice versa, for sound -on -sound
(special effects) recording. Naturally,
a source/tape compare switch is also
provided on the front panel.
The 433 is mechanically and electrically separable into four parts that unscrew and unplug for easy replacement
in servicing. The top section has the
supply and take-up reel motors, together with associated electronics. The
center section contains the capstan
motor and flywheel, tape -gate solenoid,
and record equalization switch. A side
mination, respectively. A single multi section holds the tape -motion controls
and relays, and the bottom section contains all record/playback electronics.
.
.
68
Controls on the right consist of two
mechanically interlocked, three -position lever switches which defy user
error. Pause and record buttons are
above the levers, and a three -position
lever on the left side of the deck selects
speed by moving a rubber belt between
the capstan motor's stepped pulley and
the flywheel. A four-digit resettable
counter, above the speed selector, is
driven off the supply reel. A remote
pause button at the end of a long portable cord (which plugs into the rear of
the deck) allows momentary pauses to
be made during recording or playback.
The Viking 433 has three four -pole
motors. One drives the two -pound, dynamically balanced capstan/flywheel
assembly, while the others drive the
supply and take-up turntables directly.
A tilt -away pressure roller simplifies
tape threading through the straight
slot as shown in Fig. 3.
The entire head assembly (see Fig.
3) is removable by unscrewing two
screws and unplugging three molded
head connectors. A spring -loaded pressure pad is used al the left-hand guide
and two pin guides between the erase
and record heads and after the playback head, both attached to the movable gate, provide the necessary tracking for correct contact between the
tape and heads. Braking is dynamic,
with no mechanical brakes whatsoever.
One result of this is that, in threading
the tape, the reels are completely freewheeling. For someone used to mchanical brakes, there might initially be a
tendency to spill tape during threading, but once familiar with reels that
are completely free to turn in either
direction, one can thread very quickly,
with little tension applied to the tape.
An idler/run-out arm acts as the tape end and tape -break sensor, shutting
everything off at the appropriate time,
in addition to doing its duty as final
tape guide before the take-up reel.
Seven plug-in printed circuit cards
comprise the 433's all solid-state electronics. They are divided according to
function, and each is removable. Playback equalization and record bias are
adjustable from the rear of the deck.
See Fig. 4. But since the rear cover has
an interlocking a.c. power connector,
a "cheater cord" is required to make
these adjustments while the machine
is running.
Performance
As expected, the unit performed exceedingly well throughout all our tests.
Wow and flutter, measured at beginning, middle, and end of tape reel, and
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sansui 2000
S
Sansui Electronics Corpora ion 34-43 56th Street Woodside, N.Y. 11377 Phone: (212) 446-6300
Sansui Electric Compary, Ltd. Tokyo, Japan
Electron
7.
_'istributors (Canada) British Columbia
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Equipment Profiles (continued)
ere
_mend&
11111
Fig. 2-Rear view of tape deck showing four demountable sections.
Fig.
capstan and tilt -away pinch roller.
Note the easy access for cleaning and demagnetization.
Fig.
3-Head assembly, showing
Fig.
5-Playback frequency response. Test tape
was full -track, which
71/2 ips.
accounts for the boost at 100 Hz at
4-Plug-in electronics shown with metal shield removed.
0
100
10k 20k
1k
FREQUENCY (HERTZ)
Fig.
6-Record/playback frequency response.
10
7
ips
ipst
1;ips.
'
20,
20
10k
1k
100
20k
FREQUENCY (HERTZ)
then averaged, was 0.14% total with
0.05% wow at 71/2 ips. At 3% ips, the
machine was better than 0.20% total
with 0.12% wow. At 17/e ips, wow and
flutter was better than 0.4 total. These
figures are excellent, comfortably exceeding the manufacturer's specifications. Fast forward/rewind time was 70
seconds for 1200 feet on tape on a 7 -in.
reel, as specified.
The playback frequency response, as
shown in Fig. 5, yields a response of
50 to 15,000 Hz ±3 dB at 71/2 ips; 50 to
7,500 Hz ±4 dB at 3% ips. This response is very good, although the rising
high end could probably be readjusted
with the playback equalization control
at the rear of the machine to give us
a flatter curve. With the above -mentioned adjustment made, the unit is
certainly suitable for high -quality reproduction of recorded tapes, being limited only by the fidelity of the source
material.
The record/playback response, shown
in Fig. 6, yields 40 to 20,000 Hz ±3.5
dB at 71/2 ips, 40 to 15,000 Hz ±4 dB
at 3% ips, and 50 to 8,000 Hz ±3 dB
at 17/s ips. The response here also rises
at the high end, probably due to a
slight error in playback equalization.
Also, Scotch 202 tape was used for our
tests and, although not specified, most
likely the machine was factory adjusted
for the standard Scotch 111 tape, which
would account for the rest of the peak
at the high end. Even with the response
as it stands, however, the unit meets
its specifications. The record/playback
signal-to-noise ratio measured 57 dB
below the 3% distortion level, un weighted for both top speeds, except
that the test sample's right channel at
3% ips was only down 54 dB. These
measurements fall within the specs,
and are really quite good. Crosstalk
was measured at 50 dB down at 400
Hz, both ways, which is just fine for a
quarter -track machine. In matters of
distortion, or the absence of it, the
Viking 433 stayed below 1% harmonic
and 2% intermodulation, recorded
-10 dB from 0 level. Input and output
levels were as specified. One couldn't
ask for anything more from the machine.
In sum, the Viking 433 performed
quietly and flawlessly in both recording and playing hack of tapes. Mechanical operation was positive and smooth,
and the sound was definitely "high fidelity." The use of three tape heads,
each expressly designed to perform a
specific task, enhances performance of
the tape deck. The playback head, for
example, has a 50 micro -inch gap; the
record head, a 500 micro -inch gap; and
the erase head, a double gap. All are
quarter -track types, naturally.
Thus, it looks like the Viking 433
stereo deck is a winner.
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AUDIO
70
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NOVEMBER 1963
KENWOOD
TK -140x
i+..6NWrJ00
.K-,ÁOX
di"
3
AM/FM Solid State Stereo Receiver
200 watts music power
FET, super -sensitive Front -End 4 new Integrated Circuits
NEW SENSATION
...
..
,
the moment you turn it on you'll know the KENWOOD TK -140x is ALL NEW
in the brilliant blue luminous
dial that glows from dark to bright
has a new
large tuning meter, too.
NEW BEAUTY
NEW SENSITIVITY .. a superb 1.7 microvolts that starts
with the 3 FETs 4 -gang tuning condenser, 4 integrated
IF circuit front-end.
.
...
... so discerning ... especially in
major metropolitan areas where there are two FM stations
on the same frequency, a mere 1 dB difference is all that
is necessary for the TK -140x to capture one station
and completely reject the other.
NEW SELECTIVITY
... 200 watts (4 ohms) to drive the least
efficient speaker systems with power to spare. TK -140x
gives you 2 sets of stereo speaker outputs and a front
NEW POWER
headphone jack.
...
the reason for all the newness. The
TK -140x reproduces every delicate tone, every subtle
nuance of the original sound with complete fidelity.
NEW SOUND
Of course, some things we wouldn't change .. like the
traditional KENWOOD quality and dependability.
Turn on the NEW KENWOOD TK -140x for a new sensation
in listening pleasure. Visit your nearest Franchised
KENWOOD Dealer or for colored, illustrated brochure,
write to:
.
the sound approach to quality
S. Broadway Plc., Los Angeles, Calif. 90007
69-41 Calamus Avenue, Woodside, N. Y. 11377
Exclusive Canadian Distributor-Perfect Mfg. & Supplies Corp.,
3700
AUDIO
Check No.
71
on Reader Service Card
NOVEMBER 1968
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71
Equipment Profiles (continued)
H. H. Scott LT -1128-1
FM Stereo Tuner Kit
MANUFACTURER'S SPECIFICATIONSUsable Sensitivity (IHF): 1.8 /t,V. Cross Modulation Rejection: 90 dB. Signal-to Noise Ratio: 65 dB. Total Harmonic Distortion: 0.8°/e. Frequency Response: 5015,000 Hz ±1 dB. Capture Ratio: 2-5 dB.
Selectivity: 45 dB. Stereo Separation (1
kHz): 40 dB. Audio Output Level: 1.2 V
rms. Dimensions: 15 in. x 121/2 in. x 41/a
in. high. Price: $199.95.
Years ago the prospective kit builder
was warned against attempting construction of a tuner until he had
attempted less -critical construction
projects, such as an amplifier or a preamplifier. A number of important advances have enabled H. H. Scott to develop a tuner kit that can be assembled
with such ease that even the neophyte kit -builder need not be afraid to
tackle it:
(1) Prealigned, modular printed-circuit sections (six, in all) reduce the
amount of actual wiring to an absolute
minimum. Most of the wiring is confined to interconnections between the
modules and the power supply and
selector switch sections. (2) The critical front end is completely wired and
aligned. (3) Alignment of other tuned
circuits can be accomplished quickly
and easily without using a single instrument: (4) The 78 -page construction manual is written and illustrated
in a manner that fairly invites the kit builder to dive in and "build" without
the usual fears associated with kit
building. Full color diagrams show
actual placement of wires and parts,
and assembly and wiring instructions
are grouped in easy -to -follow sections.
In addition, the manual serves as a
well -written primer for anyone interested in the theory of FM and stereo
FM.
The kit was assembled by a person
who had never made such an attempt
before. Except for a slight bending of
a dial pointer to eliminate contact with
the dial face, and a rather sloppy job
of dressing some long wire lengths
(which did not affect performance), he
did a perfect job in about 10 hours. Precut, pre -stripped and pre -tinned wires
assisted greatly.
tory -assembled units. It does not have
a "home -built" look! A rich-looking
gold and charcoal -brown dress panel is
offset by a subdued dial -glass area that
employs soft-blue numerals to indicate
frequency, as well as a 0-100 logging
scale. The multi -function tuning meter
is also contained in the dial glass area.
The lower half of the panel contains
three selector switches, a stereo indicator light, a standard stereo jack from
which an output can be obtained for
making tape recordings. (The stereo
indicator lamp lights up blue, which
doesn't make for good contrast. A red
reflector would have been preferable.)
The first of the selector switches turns
on power to the unit and, in its alternate positions, introduces sub -channel
and noise filters for the elimination of
noise in less -than -optimum stereo reception situations. The second switch,
-
Closeup of
multi -function tuning meter that is
also used during
final alignment of
Fig. 2
the Scott LT -112B
FM stereo tuner kit.
labelled "selector," enables the listener
to choose mono or automatic stereo
listening, with or without interstation
muting. The third switch selects the
various functions of the meter. Its positions include "signal strength" (in
which the meter is a "peak reading"
one), "multipath" (in which the meter
indicates presence or absence of signal
reflections detrimental to good stereo
FM reception), "center tuning" (in
which the meter becomes a "center of
channel" indicator, for optimum station tuning) and finally, "align" (in
which the sensitivity of the meter circuit is altered to permit its use during
initial r.f. and i.f. alignment upon com-
pletion of the kit). A close-up view of
the meter face is shown in Fig. 2, illustrating its dual scale calibration.
The tuning knob is located at the
upper right of the panel, and its action
is fairly smooth and precise, good use
having been made of a heavy flywheel
assembly.
In addition to the usual left and right
outputs and antenna terminals, the
rear apron of the LT -112B has a pair
of jacks for connection to the vertical
and horizontal inputs of an oscilloscope. This can provide more meaningful indications of multipath fhan can
be obtained by means of an internal
meter. With a 'scope connected, it is
also possible to judge centered -tuning,
as well as modulation pattern of any
given station. For example, Fig. 7
shows a mis -tuned condition with relatively high modulation from an FM
station. In Fig. 8 we deliberately modulated a signal generator ±300 kHz
(more than would ever be encountered
in broadcast practice) in order to display the perfectly symmetrical, wide band response of the i.f. system. The
rear of the tuner also contains right
and left level adjustments, so that
tuner output levels may be adjusted
to match other program source levels
associated with the user's overall music
system.
Top and bottom views of the completed chassis are shown in Figs. 3 and
4. Careful examination of the underside of the chassis discloses that no
effort was made to "dress" wires neatly
-we deliberately wanted to check performance of a set that might be built
by a rank amateur, as this one was.
Circuitry
The circuit of the Model LT -112B
tuner, as previously mentioned, consists of several modules. The FM front
end contains four solid-state amplifying devices, three of which are FET's.
Five NPN devices are used in the 10.7 MHz i.f. and limiter strip (which also
Figs. 3 and 4-Top and bottom views of completely assembled kit. Lead wires were not
routed as neatly as one would wish, but the tuner operated perfectly after assembly by
a kit -assembly "beginner."
Features
The finished appearance of the LT 112B rivals that of many quality, facAUDIO
72
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NOVEMBER 1958
.
Jensen Mfg. Div., The Muter Co., 5655 W. 73rd St., Chicago, III. 60638
Like a lot of guys, you're probably
having a passionate affair with your
pet stereo album. And some groovy
45's. Right.
You keep them in top shape. No
dust. No static. Not one little scratch.
And they sound great. That's beautiful.
And if you were rich, you'd probably
buy the most expensive speaker system you could.
But you're not. So what do you do?
That's where we come in. We've
built two completely new speakers.
The TF -25. And the smaller TF -15.
We put a ten -inch FLEXAIR R' woofer plus a horn -loaded tweeter in the
AUDIO
NOVEMBER 1968
TF -25. And in the TF -15, we put a
special eight -inch woofer and a dy-
namic cone tweeter.
We built them to sound like
lion bucks. And they do.
a
mil-
No distortion. No break-up. No
coloration. The brass sounds like
brass. And the strings like strings.
True fidelity. That's beautiful.
This weekend. Take your favorite
side to anyone of our dealers. Listen
to it through the TF-25. Or the TF -15.
You'll hear exactly what we mean.
There's something else that's beautiful about our two new speakers. The
price.
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The TF -25 sells for only 89.50. And
the smaller TF -15 for 44.40. That's
beautiful. Right.
Who knows. This could be the start
of another love affair.
d
I
ICI
ens en
for people concerned
about the way life sounds.
73
Equipment Profiles (continued)
1
CO
-dB Limiting (1.6pV)
0
L Out With L-Only Applied
IHF Sensitivity
-
D -20
2.1
a 1-3
pV
(0.4Yo)
.R
O -40
Lu -50
> -60
H
á -70
m
-47dB
co
3
e-/ate Noise
& Distortion .......
............................
SidEle!
t-
a
t-
-10
O -20
w
Noise
R
Out With L-Only Applied
With Filter:
>
Jw
/
No Filter
-30
w
ct
0.2
0
1.0
10.0
100
-40
20
200
RF INPUT (MICROVOLTS)
Fig. 5 -FM characteristics of Scott LT -112B tuner kit after assembly
by a neophyte kit builder.
Fig. 7 (left) -With an oscilloscope connected to a pair of jack receptacles provided at the rear of the LT -112B, a mis -tuned condition
can be easily detected. Fig. 8 -Excellent i.f. bandpass response is
displayed with a sweep generator's ±300 kHz applied.
100
10k 20k
1k
FREQUENCY (HERTZ)
Fig. 6 -Stereo FM separation with and without sub -channel filter
introduced.
Fig. 9 -Visual display of FM stereo separation (graphic plot may be
seen above) of the Model LT -112B stereo tuner at (A) 1000 Hz and
(B) 10,000 Hz.
(A)
employs a ratio detector as the FM
demodulator circuit). The multiplex
printed -circuit module employs the
popular "switching" circuit for demodulation and includes the automatic
switching circuits developed by Scott.
In these circuits, switching will only
occur (to stereo) if there is sufficient
pilot signal to insure good synchronization with the locally generated 38 -kHz
signal. Additionally, the switching circuit requires a greater signal-to-noise
ratio for it to switch to stereo than for
it to switch back to mono. This prevents a marginally acceptable signal
from intermittently switching back and
forth from mono to stereo. Seven transistors are used in this carefully designed circuit. A small muting -circuit
module consisting of two transistors, a
"multipath indicator" module consisting of a transistor and two diodes, and
an audio-output amplifier module complete the complement of p.c. boards.
The latter includes four more transistors as well as the 38 -kHz and 19 -kHz
rejection filter components and level
adjustments for left and right output
signals.
Performance
In evaluating the specifications and
measurements which follow, the reader
is reminded once more that this unit
was built per the instruction manual
and aligned without the use of any
professional test equipment. While it is
remarkable that most of the specifications of the completed kit were met
or exceeded, further alignment using
instruments might, we felt, yield even
better results. Amazingly, the IHF
sensitivity could not be improved upon
using standard alignment procedures.
This speaks very well indeed for the
factory alignment of the front end, as
well as for the techniques developed
by Scott for home alignment without
the aid of instruments. Much of the
FM performance story can be gleaned
from Fig. 5. IHF sensitivity at 98 MHz
was 2.1 f,t,V, while at 108 MHz (not
shown) it measured 1.9 Ft V, which is
right on the specification nose, allowing for normal production tolerances.
Ultimate signal-to-noise ratio was exactly 65 dB, as rated, and total harmonic distortion was only 0.4% as
against the published figure of 0.8%.
Full limiting was achieved with a mere
input of 1.6AV!
Stereo FM separation was 35 dB at
1 kHz,
a very fine figure, though
slightly less than the spec's. Separation at other frequencies is shown in
the plot of Fig. 6. Also shown here
is the effect on separation when the
sub -channel filter is introduced. Note
that at the very -high audio frequencies
separation is seriously degraded by the
74
filter, as admitted by Scott. Therefore,
the filter is really intended for situations in which reduced separation is
preferred to very noisy, weak -signal
stereo reception. A dual plot of stereo
separation is shown in Fig. 9 for 1 kHz
and 10 kHz signals.
In use, the Model LT -112B confirmed its measured specifications. At
a distance of some 25 miles from the
center of the Metropolitan New York
area, we were able to receive 38 stations clearly, 12 of which were transmitting stereo FM. None of the twelve
required the use of the sub -channel
filter. Any evidence of distortion was
clearly a case of multi -path problems
(as confirmed by the self-contained
meter, as well as by scope readings)
which were almost completely cleared
up by a slight reorientation of our
antenna.
If you lean towards kit construction,
and have steered clear of FM tuners
until now, the Scott LT -112B may well
serve as your introduction to this fine
program source. You might remove
the bottom cover every so often,
though, or they'll never believe you
built it yourself. More importantly, the
stereo FM tuner works beautifully.
And there's nothing on the market that
is factory -assembled to match its performance, features, and appearance at
its price.
Check No. 72 on Reader Service Card
AUDIO
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NOVEMBER 1968
TIFIE
INAUDIBLE
WOOF!
A tympani crescendo with a hole in the
middle, a half -bar rest effect in place of a
bassoon Bb, a Valhalla that ends with a whimper,
musical lows that fade into nothing-all these
are Inaudible Woof phenomena.
And the world's finest pickup and
amplifying equipment can't make your living room
immune to it.
The cause of this audio abnormality is
known as a standing wave-a dirty acoustical
trick that builds 'dead' spots into concert halls and
makes liars out of speaker systems.
It happens when a bass tone coming out
of your woofer meets its own reflection coming
back. That's when 1 + 1 = O.
And that's The Inaudible Woof.
It's also the first thing we designed out
of our Grenadier speaker systems.
Your old physics textbook will give you
the math on nodes and loops and reflections
and reciprocals.
We'll simply point out that as sound
waves emerge from your speaker enclosures the
distances they travel from woofer to walls and
back again are seldom equal.
As they meet themselves coming and
going, they often intersect out of phase. That's
when you have a standing wave.
And an Inaudible Woof.
We designed this problem out of
Grenadiers by facing the woofer down.
EMPIRE Empire Scientific Corp.
AUDIO
NOVEMBER 1968
Instead of bouncing bass waves around
the room at random, a Grenadier's woofer reflects
them from the floor. They travel almost no
distance at all to the primary reflecting surface,
and that distance never varies.
Instead of a half -dozen significant
reflections that can set up standing waves, you
get a single, full -dispersion reflection.
Instead of traversing the width of the
room for reflection and reinforcement, a
Grenadier's bass tones travel mere inches to the
floor for full, faultless, unwavering concert -hall
sound.
No standing waves. No Inaudible Woof.
And, naturally, you get the converse
benefit, too. No ear-splitting, sonic -boom bass
blasts, either.
GRENADIER SPEAKER
SYSTEMS
The
The Royal Grenadier
1055 Stewart Avenue
$299.95
Grenadier 7000
The Grenadier 5000
$209.95
$179.95
Garden City, N.Y. 11530
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75
Electronic
Organs
NORMAN H. CROWHURST
Part
MANY READERS of this magazine
have probably toyed with the idea
of making their own organ. You can
do this, of course, by using one of
the kits now available from several
manufacturers, which can save you
much money by doing the assembly
yourself.
Schober and Artisan each specialize exclusively in organ kits and,
using slightly different approaches,
enable you to build as much or as
little organ as you like, or can afford.
Or you can start small and build on,
to make your organ bigger, as funds
are available. Heathkit has Thomas
organs in kit form, with "Band
Boxes" that can be added later to
create different rhythms, as well as
one to automatically add percussion
instrument sounds.
These are ways of saving money
and getting a good organ, if you
want to do the work yourself. But
another idea has intrigued a number
of readers: that of completely designing and building their own organ. I know this from the letters I
receive asking for advice on how to
do one or other part of it.
It seems these readers would like
a good organ, but the price tag deters them, and they have convinced
themselves they must be able to
build one cheaper themselves.
Actually, I'm a great advocate of
the home constructor who figures
out his own ideas, because many of
our best developments started that
way. And I know how hard the bug
can bite. So maybe you who suggest
this should get the bug out of your
system by trying it. At least enough
to find out what the problems are.
After that you will have a healthier
respect for the manufacturers who
make good organs at what is really
a very reasonable price, instead of
continuing to think the price is too
high!
3
of a series
What a home constructor
would have to go through to
build his own electronic organ, with special focus on
generators
When you try to build your own
generators, the first problem you'll
hit is holding the notes on key. Assume you're going to design yourself
an oscillator to generate 'A' of 440
Hz. How close does this have to be?
The musical scale is divided into
12 semitones, representing a ratio
from one note to the next of
1.059465496:1. This ratio is the 12th
root of 2. To sound true, each note
must stay close to its'own frequency.
It cannot possibly wander anywhere
near the frequency assigned to the
next note.
For precision tuning, musicologists divide each semitone interval
into 100 cents, which means this interval is the 1/1200th root of 2,
which represents a change in frequency of less than 0.06 of 1%. Actually, so small a change can only
be heard by the most highly trained
ear.
Musicologists generally concede
that most musical persons' ears can
detect a change of pitch, as out of
tune, when it reaches about 5 cents,
which is still only 3/10th of 1%
variation in frequency.
Of course, crystal control can hold
ratio frequencies much closer than
that. But do you intend to crystal
control every frequency on your organ? If so, you'll make the organ
manufacturers' price look quite low
by the time you're through!
To make the many different frequencies produced by an organ stay
closely enough in tune, at the cost
you have in mind, you're going to
have to find a way of making a rela-
76
tively inexpensive oscillator hold its
frequency much better. So let's take
a look at the problem.
The Electromechanical
Approach
Hammond, and the English
Compton, solve it very well by using
precision mechanical drives for their
electromagnetic and electrostatic
generators, respectively. If the
whole drive changes speed, the pitch
of the organ will change, but it will
still be in tune with itself. Do you
want to take a crack at copying one
of them?
The Compton approach would
probably cost you a million dollars,
to make just one organ. So that's out
for a one-shot deal. Of course, having tooled for the job, you could
manufacture organs for much less
than that, but they'd never be
"cheap."
Taking the other choice, how are
you going to shape the teeth of the
tone wheel, Hammond style? What
shape gives precisely sine -wave output? Assuming you are smart at
lathe work and can do that part, now
you've got to face some pretty complicated switching, between the
drawbars and the manual keying, to
synthesize the various voices you
want.
Hammond has gone through all
this and reduced the whole process
to a production basis. And they've
been producing good organs this
way, competitively, for a good many
years now. Do you really think you
could make a job of it, for less than
you can buy a Hammond?
Electronic Generators
So let's look at the possibilities of
doing the electronic job ourselves.
What kind of oscillator shall we use?
AUDIO
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NOVEMBER 1968
Our A.P. Van Meter designed the PRO -120 so well,
he had to go through
the indignity of being double checked.
bright idea, "Why not ask them to
certify that the Pro -120 will meet or
exceed its published specifications?"
Who ever heard of
double checking the
head project engineer,
just because his design
seemed too good to be true? Yet,
that's exactly what happened
when A.P. first submitted the
specifications on his new Studio
Pro -120 FM Stereo Receiver.
The men from U.S. Testing agreed,
but on one condition. They wouldn't
test a Pro -120 at their lab. (After
all, anyone who cares can "tune-up"
a unit just as you would a car.)
Instead, they would come to University
in Oklahoma City and pull units at
random right off the production lines.
"A.P.," management said, "we
believe you, but why should anyone
else? These specs are simply too good
to be true in a receiver that sells
And that's how the University Studio
Pro -120 came to be the world's first
and only certified receiver. Just
because it seemed too good to be true.
for $379.50!"
And that's when they got the idea for
the double check.
What about A.P.?
They called Nation -Wide Consumer
Testing (a division of no less august body
than the U.S. Testing Labs) for an
impartial analysis of A.P.'s work.
Well, getting his baby certified made
believers out of lots of people. Including
the boss. So, instead of a double check,
A.P. now has the dignity of a doubled check.
Then somebody in sales got another
1
V
/
UNIVERSITY
SOUND
DIVISION OF LTV LING ALTEC. INC.
A
J
9500 West Reno
PRO -120
AUDIO
NOVEMBER 1968
the only receiver with certified specs
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&
Oklahoma City, Oklahoma 73126
performance t
77
ALL EXCEPT THIS PIECE
IS PERFECT SINE WAVE.
CORRECT
FREQUENCY
3.5% HIGH
_-
Fig. 3-1
3.5% LOW
Fig. 3-2
Fig. 3-1-A waveform to illustrate the problem of stability in a tuned -circuit oscillator designed to produce a waveform close to sinusoidal. The waveform is a perfect sine wave,
except for a flattening at the top, that reduces amplitude in that direction by 2.5°/o (0.025).
This waveform would measure only 0.15% distortion, but for this reason is susceptible
to a frequency deviation of about ±3.5°/o.
Fig. 3-2-Only the length of the flat part in the waveform of Fig. 3-1 is changed. The rest
of the perfect sine wave is unchanged. But the effective frequency change due to this is
enough to make the generator unsatisfactory for organ use, regardless of the kind of
oscillator circuit used to generate it.
HIGH PURITY
TONE
GENERATOR
for you.
LIMITER OR
DISTORTION
BUFFER
STAGE
FORMANTS
STAGE
-
I
ALTERNATIVE POINTS FOR KEYING
3-3-Using the pure -tone concept of tone generator, each note on the organ needs
the first three stages shown here in order to use the formant method of timbre selection.
Keying can be effected after either the 2nd or 3rd stage. The formants may be common
to the whole organ or to whole sections (an octave or more) of notes.
Fig.
SUPPLY
R2
+
TO NEXT
MASTER
OSCILLATOR
Cl
DIVIDER
Rl
C2
MASTER
OSCILLATOR
1st DIVIDER
2nd DIVIDER
OUTPUT
OUTPUT
VIBRATO LINE
3-4-A typical master -oscillator -with -dividers circuit, using transistorized oscillator
and dividers. With slight variations, this kind of circuit is used by several manufacturers.
Fig.
B+
R3
DIAPSON
OUTPUT
FLUTE
OUTPUT
STRING/
C3
REED
OUTPUT
Will it be a tuned circuit, or a multivibrator type?
In audio engineering, the tuned circuit type is sometimes regarded
as the most stable. To hold stability,
the "L" and "C" must stay put. So
you buy yourself high -stability, low
temperature -coefficient L's and C's.
There goes the cost again. By the
time you have enough for all the
oscillators, you'll have spent enough
to buy a pretty good organ, before
you even start building.
Actually, for an organ -type oscillator, the variation in L or C value
isn't even the biggest cause of frequency change. So you've wasted
your money, as I know quite a few
people have done. Assume for the
moment you have an L and a C that
stay absolutely fixed in value. If you
can use them in an oscillator that
uses exactly 100% feedback, then
your L and C will fix the frequency
3-5-Modern Conn organs use an interesting combination of tubes for oscillators, with transistors for keying. The
oscillator circuit, shown here, delivers
three different kinds of waveform, used
for different groups of stops, which add
different formants to these forms.
Fig.
BIAS & TREMOLO
BUS
78
A variety of classic circuits can
make such an oscillator. Here's the
rub: if the feedback is 100.001%, the
tone slowly builds its output level
until distortion stops it from getting
any bigger; if the feedback is
99.999%, the tone slowly dies away
(assuming you somehow got it
started in the first place) and quits.
How are you going to control the
gain of your active element (tube or
transistor) to give such a precise
100% feedback?
Take the waveform of Fig. 3-1. On
an average -reading meter, this has a
measured harmonic content of
0.15%, which is pretty pure. The
ratio of the peak deviation from
sine wave to the fundamental's peak
amplitude is 2.5%. And the duration
of the deviation is 1/7th of the half
wave in which it occurs, or 1/14th
of the whole wave.
For 13/14th of its period, the
waveform is a perfect sine wave, and
thus controlled by the L and C
values. For the other 1/14th, it can
be influenced by external circuits,
via power supply, output coupling,
etc. Assuming such external influences can squeeze the actual duration of this nominal 1/14th to half
of that, or extend it to one -and -a half times that, the resulting variation in total period is 1/14th of the
nominal period (Fig. 3-2) . The only
AUDIO
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AUDIO
NOVEMBER 1968
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COUPLER
79
part that changes is the duration of
the flat piece.
Thus a frequency adjusted to be
440 Hz can vary as much as from
408.5 Hz to 471.5 Hz. The adjoining
semitones have nominal frequencies
of 415.3 and 466.16 Hz. So this 440
Hz nominal note can easily wander
into the frequencies belonging to adjoining notes. The precision of the
L and C values doesn't help at all,
unless some very careful isolation is
used as well.
But suppose, for the sake of argument, you get a nice pure wave, as
viewed on your oscilloscope, and its
frequency is stable within, say, 0.3%.
This means the circuit has a working
Q factor of 300 or more. You can't
switch this oscillator on and off as a
way of keying the notes. It will have
a build-up and decay time-constant
of more than 300 periods. Middle C,
with a frequency of 261 Hz, will take
more than a second to "speak."
So you must keep it oscillating all
the time and key its output in some
way. How do you connect the output? Any connection to the circuit
loads it. To get this degree of purity,
you have just the gain to produce
100% feedback, ± 0.03%. This precise amount of feedback depends on
a precise resistance value at the part
of the circuit where the output is
connected. So the external resistance must be more than 3000 times
that of the circuit to which it connects if it is not to change the circuit's operation by another 0.03%,
with a potential frequency shift of
0.3%. To achieve this, you'll have to
use a pretty well-designed buffer
stage, and then do your keying after
the buffer stage. Already you're
thinking of ways of doing the job
that will be more expensive than
those used by some organ manufacturers.
Actually, most organ manufacturers that use what look like tuned
circuits don't even try to maintain
that order of purity. The harmonics
can be useful as part of the voicing.
If you try listening to a sine wave,
the first thing that will strike you is
that its not much of an organ tone,
or any other musical tone. No musical tone ever sounded that "pure."
You've got to add harmonics
a -plenty to give it any kind of timbre, even flute or diapason. So, having generated a relatively pure tone,
you now have a choice: distort it to
put in the harmonics, and then use
formants to produce various timbres; or synthesize, which means
adding in various pure -tone harmonics with switching and separate controls.
The first is relatively easy to do,
and controlling timbre with formant
circuits is fun, even though it may
take you quite a while to find the
effects that sound realistic enough to
suit you. But it now involves (1) a
precision pure -tone oscillator for
each note; (2) a buffer stage to isolate the oscillator from the switching; (3) a distorting stage to put in
3-6-A popular method of getting vibrato. Biasing on the diode, D, parallels
small capacitor C3 with the main tuning
capacitor CI, for part of the vibrato
period, thus changing frequency with
virtually no amplitude change.
Fig.
a sackful of harmonics and (4) the
formant circuits to produce the desired musical qualities (Fig. 3-3)
As multivibrators produce stage 3
directly, for each note, we can see
why most organ makers use a set of
master oscillators, to which they
couple frequency dividers that work
on the multivibrator principle, producing a virtually square wave (Fig.
.
3-4). Even the master oscillators
don't try to work as high purity
sine -wave generators. If you've
played with the ideas we just finished discussing, you know why!
Actually, it is easier to control the
frequency of an oscillator that isn't
quite so pure. Although the master
oscillator circuit looks like the traditional tuned -circuit oscillator, it is
better understood if you view it as
controlled by the combined time constant effects of L, Cl and C2. It
oscillates hard, limited by the additional loading of R2 and R3 across
the voltage divider formed by Rl
and the transistor during the part of
the period when D is conducting.
Taking the output from this point
also obtains a somewhat "squared"
waveform. This circuit is similar to
that used by Thomas organs.
80
Using harder oscillation, so frequency is controlled by time constants rather than reactances, yields
better stability, but the design still
takes a lot of experimental work.
Some organs get two or more kinds
of tone from the one oscillator (Fig.
3-5) . This is one of the Conn circuits. This type of organ uses separate oscillators, one for every note.
The most sinusoidal tone comes
from the cathode tap of the oscillator coil. This is used for flute -type
tones. The resistor in the ground
lead picks up a pulse that reflects
grid -current charging on C2, whose
value is smaller than C1, the main
tuning capacitor.
The plate gives an output in
which tube current pulses discharge
C3, leaving it to recharge through
Rs, yielding a sawtooth output. The
inductor has variable -core tuning.
This method of providing different
basic output waveforms makes voicing with formants easier after keying. Formants can only modify
harmonics already in the waveform
you start with. They can't completely eliminate any, and they can't add
harmonics that aren't there.
A symmetrical waveform has no
even harmonics, only odd ones, and
thus simulates a closed organ pipe
quite well. An asymmetrical waveform has at least a strong second, or
octave overtone, which is important
for some tone qualities. A sawtooth
has them all, fairly richly. And a
spiky, or pulse -type waveform, is
rich in the higher harmonics, giving
a reedy effect.
To provide two or more kinds of
output for the whole organ normally
requires an oscillator for every note,
which Conn uses, not just a master
set of 12. As was said in the previous
installment, this sounds like "more
organ," but its also a lot more work
to make and tune.
The synthesis method involves
virtually the system used by Hammond, but using electronic instead
of electromagnetic sources. Some
manufacturers synthesize by combining different waveform outputs,
or by using coupling from other generators. But to our knowledge, Hammond is the only one to use complete
tone synthesis.
(Continued on page 99)
AUDIO
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NOVEMBER 1968
New
developments
in the great
bass revival.
Last year, when we introduced the Fisher XP -18
four-way speaker system with its huge 18 -inch woofer, we predicted a
renewed interest in bass among serious audiophiles.
We pointed out that no bookshelf -size
speaker, not even the top Fisher models that
The new XP -15B
are famous for their bass, could push the low
frequencies around a room with quite the same
authority as a big brute like the XP -18.
This came as no surprise to those
who remembered that a 40 -cycle sound wave
is more than 28 feet long. That's why it takes a
double bass or a contrabassoon to sound a note
that low. Bass and big dimensions go together.
But the sound of the big XP -18
did surprise a lot of people. They knew it
had to be good at $330, but they weren't
prepared for a completely new experience.
And then came the obvious request:
Couldn't we make the XP -18 concept available in
more moderately priced speakers?
We could. And did: in the new Fisher XP -12 and XP -15B.
The new XP -12
They're a little smaller (24" x 221/2" x 133/4" and
27" x 27" x 143/4", respectively), but still twice as big as bookshelf speakers.
They're three-way systems instead of four-way, but they have the same type of
small cloth -dome tweeter and 8 -inch midrange driver with molded rubber surround.
The main difference is in the woofers: a 12 -inch unit with a 6 -lb.
magnet structure in the XP -12 and a 15 -inch driver
with a 12-Ib. magnet structure in the XP -15B.
Mail this coupon for 1
your free copy of The
The prices justify the slight comedown
Fisher Handbook
in woof -inches; the XP -12 is listed at $199.95 and the
1969. This reference
guide to hi-fi and
XP -15B at $269.95.
stereo also includes
How do they sound? Not quite like the XP -18.
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Name
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City
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Zip
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AUDIO
NOVEMBER 1968
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101.
81
ABZs of FM
LEONARD FELDMAN
The Discriminator
as an FM
Detector
Having followed the FM signal
through its conversion to an i.f. of 10.7
MHz and its subsequent amplification
and limiting, we now have to remove
the audio information from its i.f. carrier. This process is known as FM detection or FM demodulation. The two
most popular circuits used for this vital
function remain basically unchanged.
They are the so-called Foster-Seeley
Discriminator and the Ratio Detector.
We shall first examine the discriminator.
Figure 1 is a schematic of an early
form of discriminator and, although it
is not in use today, it is simpler to understand than the later -developed
Foster -Seeley type. Ll and Cl form
the output load of the preceding final
limiter stage. This tuned circuit is
broad enough to pass the 200 kHz (or
more) bandwidth deemed necessary in
FM reception. L1C1 energy is inductively coupled to two secondary tuned
circuits, L2C2 and L3C3. To obtain
FM detection, L2C2 is tuned to a frequency about 100 kHz below the i.f.
frequency (10.7 MHz), while L3C3 is
tuned above the i.f. center point by an
equal number of kHz. Figure 2 is a
combined plot of the response curves
of the two adjacent resonant circuits.
Note that the L3C3 response curve is
inverted with respect to the L2C2
curve, indicating an inverted polarity
conforming with the actual hook-up
and polarities established in Fig. 1.
Thus, if the voltage appearing across
R1 is larger than the voltage across R2,
the net output voltage (with reference
to ground) will be positive. A negative
resultant output voltage will result if
the voltage across R2 is greater than
the voltage across Rl. It should be
noted that each of these resonant circuits may be looked upon as a complete
AM detector, including its own diode
rectifier, load resistor, and even r.f. bypass capacitors (C4 and C5).
Since each of the resonant circuits is
tuned to a different frequency, the am-
plitude developed across their respective loads will differ, depending upon
the instantaneous frequency present.
With no modulation present (frequency dormant at 10.7 MHz) equal,
small positive and negative voltages
will be developed across Rl and R2,
respectively. Being opposite in polarity, these voltages will cancel each
other out and the resultant will be zero,
as it should be for a "no -modulation"
condition.
Suppose now that the instantaneous
frequency shifts to point "A" as a result of some instantaneous modulation.
The voltage across L3C3 will be greater
than that across L2C2 because the frequency is closer to the resonant point
of the L3C3 circuit. As seen in Fig. 2,
the instantaneous resultant voltage developed across the combination load of
R1 and R2 will be negative. Furthermore, as the frequency of the carrier
(and hence the i.f. stages) shifts back
Fig.
1-An early version of
a
discriminator
(or FM detector).
Fig. 2-Superimposed response curves for
the secondary tuned circuits of Fig. 1.
3-Combined "S" curve of the discriminator shows linear portion (no curvature) from point 1 to point 2.
Fig.
Fig.
1
LAST
LIMITER
Fig. 2
L2C2
RESPONSE
AMPLITUDE
POINT
10.4
10.5
i10.ß 10.9
10.6
"a"
11.0
10.7
FREQUENCY
L3C3
RESPONSE
(MHz)
T
Fig. 3
10.7
10.8
10.4
10.5
10.9
11.0
10.6
FREQUENCY (MHz)
82
and forth at a rate determined by the
audio tone to be reproduced, the output across this combination load will
rise and fall through positive and
negative values, effectively converting
frequency variations into their corresponding amplitude or audio variations.
Since the output voltage is really the
difference in voltage across R1 and R2,
both curves can be represented as one
continuous curve, as shown in Fig. 3.
This is the familiar "S" curve so often
referred to in alignment instructions
for FM sets. The central, linear portion
of the curve must be at least 150 kHz
from point 1 to point 2 if distortion free audio demodulation is to take
place. Generally, 250 kHz and even
more of linear region is designed into
these circuits to insure against slight
mis -tuning away from center of channel and to further reduce audio distortion.
To summarize the action of this
early form of discriminator, it may be
said that two separate actions occur.
First, the tuned sections convert frequency modulation to amplitude modulation at i.f. frequencies. Then, by
inserting a diode detector, the audiomodulated i.f. frequencies are con converted to the desired audio. From
the foregoing, you can deduce that this
form of discriminator is sensitive to
AM variations, and it is for this reason
that limiters must be used ahead of the
discriminator, so that the discriminator
input is "pure" FM with no AM content.
From the foregoing simple analysis
we go on to the Foster -Seeley, shown
in one of its many forms in Fig. 4.
In this circuit, both secondary windings are combined and a single capacitor is used to tune the circuit to 10.7
MHz. Inductive tuning of both primary and secondary is usually employed. The discriminator output
voltage no longer depends upon difference in response of two tuned circuits
to various incoming frequencies. Instead, the voltage appearing at each
diode will depend upon the phase of
the secondary voltage as compared to
the phase of the primary voltage.
Each different frequency (above
and below 10.7 MHz) alters the phase
response of the secondary network
which, in turn, causes each diode to
receive a different amount of voltage.
From that point on, however, the action is as described before, in that the
rectified voltages across R1 and R2
give the proper audio output.
To illustrate this "phase" of discriminator theory, let us consider what
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happens first when the incoming i.f.
frequency is at its mid -point (10.7 MHz)
or with no modulation applied. The
voltage induced in the secondary E;
produces an in -phase secondary current,
since, at resonance the impedance
presented is purely resistive.
On the vector diagram of Fig. 5, E
and Ia are therefore drawn along the
same straight line. The voltage developed in L2 and L3 due to I, is 90
degrees out of phase with I,. This, of
course, is true of any inductance. In
the vector diagram, E2 and E3 (the
voltages developed across L2 and L3)
are both drawn at 90 degrees from L.
These two voltage vectors are drawn on
opposite sides of Ie because of the
reference center tap on the secondary
coil. With reference to this center tap,
E2 and E3 are 180 degrees out of phase
with each other. Now, if ETA (the equivalent primary voltage which can be
shown to appear across L4) is added
vectorially to E2 we obtain E,,,. By
adding EL4 to E3 we also obtain E,2,
the two respective voltages applied to
the diodes y, and v2. It is obvious from
the diagram that E,., and E v2 are exactly
equal in amplitude. Therefore the same
current will flow through each diode
and similar voltages will appear across
R1 and R2. Being out of phase, these
voltages will cancel and there will be
no audio output. Again, this is as it
I
Fig. 4
should be, since no modulation is
applied to the signal, which remains
static at 10.7 MHz.
By way of contrast, let us consider
the case in which the FM signal, now
modulated, swings towards a higher
frequency. As shown in Fig. 6, E;,, and
EL4 still bear the same reference relationship to each other (namely, 180
degrees apart in phase). At frequencies
above resonance, however, XL (the
inductive reactance) exceeds X,, (capacitive reactance) and the current, Ia,
will lag behind E;,,. E2 and E3 still
maintain a 90 -degree relationship to
I,, however, since that relationship
always exists between the voltage and
the current in a given coil. If we once
again add E2 to ELa and E3 to EL4,
vectorially, we see that resultant E,, is
now greater than resultant E,.2. As a
result, the voltage developed across R,
will be greater than that developed
across R2, and the output voltage will
be positive with respect to ground or
the center tap.
A similar, but opposite phase analysis by means of another vector diagram could easily be drawn for the case
in which the incoming frequency shifts
below center, in which case the output
voltage would be negative with respect
to ground. The unbalanced condition
that arises from the shifting frequency
(either negative or positive) is made
VI
4-One version of the
Foster Seeley discriminator
Fig.
circuit.
Fig. 5-Vector relationships
in the discriminator of
Fig. 4 when no demodu-
lation
Fig.5
Evi
Ev2
EL4
is
taking place. Volt-
ages E,, (across R1) and
E,2 (across R2) cause cur-
Fig. 6 Evi
rents which cancel each
other out.
E3
E2
Fig. 6-Phase relationships
EIN
when frequency is shifted
above resonance cause E,.,
to be greater than E v2, and
a net output voltage (+)
will appear across R1 and
EIN
Fig. 7
C3
R2.
MR
L2
0+
R3
VI
68K
R1
C5
1000
.
á
ó
Fig.
7-A modified version
of
a
discriminator,
in
and C5 have
been omitted, also shows
parts needed for proper
de -emphasis.
which
L4
linear with respect to frequency by
careful design of the discriminator
transformer so that the audio output
will be a faithful replica of the audio
which caused the modulation at the
transmitter. The S curve previously
shown applies equally to this design;
the linear portion can be made just as
great as in the previous case.
A modification of the Foster -Seeley
circuit is shown in Fig. 7. At first glance
you might suppose that voltage EL4,
the reference voltage needed for proper
operation of the discriminator, has been
eliminated with the removal of L4.
Actually, however, R2 is now effectively in parallel with Ll (thanks to
coupling capacitor C3); therefore E1
appears across R2. In this circuit, R2
performs a double function-it develops
the rectified voltage from the diode and
serves to apply E1, the reference voltage, to the opposite diode. The advantage of this configuration lies only
in the fact that fewer parts are required.
Rl and R2 must be high in value,
however, because they are effectively
in parallel with Ll. In the original
Foster -Seeley circuit (Fig. 4), L4
served as a choke, isolating Rl and R2
from Ll. For reasons which we shall go
into when we discuss stereo FM, the
higher output impedance can sometimes create problems in coupling to a
stereo FM decoder.
Whether a discriminator or a ratio
detector is used in a given design, there
remains one important job to be done
before the demodulated audio can be
applied to an audio amplifier. You will
recall that the frequency response of
the program material broadcast is anything but "flat" in the high-fidelity
sense. Rather, the high frequencies
have been deliberately "boosted" above
about 1500 Hz to improve the signalto-noise ratio of the overall received
signal. The. scheme is called "preemphasis." In order to restore "flat"
response, a de -emphasis network must
now be introduced. R3 and C5 in Fig. 7
serve this function. Note that the R -C
time constant, as shown, is only 68
microseconds, as opposed to 75 microseconds used at the transmitting end.
Usually, length of connecting shielded
cable and/or stray wiring capacity
make up the difference. Sometimes,
less meticulous designers will under de -emphasize recovered audio in order
to create a more "brilliant" sounding
output, but they are only deluding
themselves and the public. Further,
this causes inaccurate frequency response and a less -than -optimum signalto-noise condition.
Next month we shall examine the
Ratio Detector.
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--
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Recorded Tapes
95
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Classical
Record
Reviews
EDWARD TATNALL CANBY
Four Hants
-
Though television prospers, we
still have radio broadcasting in
totally blind form. For good reason!
We don't always want to see everything we hear. If silence is sometimes golden, then the absence of
visibility is often sweet. Often
enough, it is nice just to hear, without seeing a thing.
Music particularly. TV has had a
dreadful time, over the years, figuring out what we should look at while
serious music is playing in the TV
sound channel. (I mean, of course,
music to listen to for itself, not
background music to the TV foreground.) It's a problem.
In the concert hall, the musicians
are situated at a decent distance
from you, visible in the round but
not so you see the hairs on their
faces and the sweat on their brows.
On TV, the distant musician is
mainly a shapeless blur-not enough
lines to the inch, not enough definition. So TV moves in close. Sometimes admirably, as when. Toscanini
tortured his expressive face before
the close-up camera. But more often
in a pedestrian, uninteresting fashion; because musicians aren't supposed to act like movie actors when
they play. Most of them make
meaningless faces, or swoop and
sway around, or worst of all, merely
look deadpan. Their expression
quite rightly is in the music itself.
That's where you are supposed to
gauge their sentiments, not by looking at their faces.
Also, keep in mind, many mouth blown instruments require the players to make dreadful contortions.
Have you ever looked a bassoonist
in the mouth, close -to? Or watched
an oboeist nervously licking his
reeds, or a trumpeter blowing out
cheeks and growing redder and redder in the face? (Bright purple on
TV color.) And let us not mention
the French horn, who must periodically empty the saliva from his instrument onto the floor. Let's have
that at a distance, by all means!
To carry this one little step further, we might note-and this is the
point of my musings-that even in
the "live" form a great deal of
music -making does not bear too
close a scrutiny via the eyes. In particular, there is that happy homemaker form of musical duet usually
called "piano four hands." What
you see when you look at it is one
piano and two rears. Two people
squeezed together on one piano
bench, at one keyboard. It can be
just lovely for the two participants.
But it isn't something to look at
from the outside. Thus of all famous
and worthwhile forms of classical
music, the piano four hands literature is heard the most seldom on
the concert stage. A very great loss,
since some of the finest classical
music around comes in the once
highly popular (for home use) format. It is next to impossible to play
this splendid music on any stage, of
any sort, without extreme clumsiness in the visible aspect.
And lo!-we have records, and
stereo too. At last, we can listen to
piano four hands for as long as we
want without a behind to be seen.
And what a boon to the recording
artists! They play in privacy as far
as prying eyes are concerned. Only
the ears hear.
So in due course, over the years,
a good part of the four -handed literature for one piano has appeared
on records, much of it even before
the expansiveness of stereo gave the
four simultaneous hands the unmistakable sonic impact that belongs
to this special music-twenty fingers that span a keyboard in almost
orchestral fashion. The latest album
to reach these reviewing ears is
86
typical, the complete works of
Mozart for piano four hands, filling
up an ample album of three stereo
LPs. Some of Mozart's finest music
is on these records, the range of expression extending from his earliest
childhood years until the last days
of his short life. One piece is unfinished; it ends an LP in a startling
"cut," right in the middle of an
idea. (Easier to manage on records
than in the concert hall, come to
think of it.)
Yaltah Menuhin and her husband
Joel Ryce are the piano team in this
recording. The performances were
appropriately made in a spacious
private music room, sounding reasonably old Vienna though it happens to be in old New York, U.S.A.
The two performers integrate their
playing to the split microsecond,
with never a fraction of a degree of
phase shift between the parts; they
are one, always. The players do,
however, shift places, sometimes one
at the top end, sometimes the other.
I find that I like the husband on the
treble best, but there isn't really
much to choose. (You can find
which is where via the accompanying notes.)
Sonically, the recording suffers
from a minor and common piano
ailment, hard, percussive peaks on
some notes without a doubt due to
reflections and standing waves in
the relatively small space-small in
relation to a concert hall. Big pianos
do that. (Mozart's piano was less
powerful, with more in the overtones and a less highly charged
fundamental. So-fewer problems in
home acoustics.)
Yes, the recording is a budget job,
minus studio charges, but the tapes
are OK, decidedly. One of these
days, somebody's going to issue a
stereo recording made on a cassette
portable. Then what?
Mozart: The Complete Works for Piano
Four Hands. Yaltah Menuhin, Joel
Ryce.
Everest 3168/3 Stereo ($14.94)
Performance: B+
Sound:
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More Piano
Hindemith: Sonatas for Viola and Piano.
Walter Trampler, Viola, Ronald Turini,
Piano.
RCA Victor LSC 3012 Stereo ($5.79)
Hindemith's instrument was the
viola and these two sonatas, from 1922
and 1939, represent early and late
Hindemith for his own special use as
well as for other violists. Of the two
sonatas I enjoyed the early one bestmainly because it is one of those early
works that doesn't sound like Hindemith! His later idiom is so dogmatically
fixed, even if masterfully worked out,
that we tend to think-oh no, not more
of that sound? The early sonata is refreshingly without it.
Of the two types of violist, Hindemith was the scratchy, hoarse -voiced.
out -of -tune type, a very respectable
breed of string performer in musical
circles. (Some instruments are allowed
that sort of individuality.) But, luckily
for us, Walter Trampler is the other
sort of violist, playing a smooth,
creamy viola without a trace of harshness. Much easier in the listening! And
the young pianist here, Ronald Turini,
is a whiz; he promotes Hindemith's
piano parts with convincing energy and
enthusiasm. (Note: Trampler also has
a companion disc of solo viola music,
LSC 2974.)
Performance: B+
Follow
the
leader
Sound: B
Prokofieff: Piano Concertos Nos. 3 and 4.
John Browning/Boston Symphony/Erich
Leinsdorf.
RCA Victor LSC 3019 Stereo ($5.79)
In his younger days, living in Western Europe and often touring America,
Prokofieff was mainly a pianist, often
playing his own works-to uncomprehending audiences. The four piano concerti thus are bunched together in the
twenties and thirties, before his return
to Russia. He had a curious piano
style, wangingly percussive (in the
avant garde manner of that time) and
very thickly notated the piano seldom stops for a moment. There are the
now-familiar big Prokofieff melodies
here and there; but it was a time when
dissonance (for the "classical" modernist) was absolutely the rule, and so
you'll have to extract those tunes both
from the masses of piano notes, by the
millions, and from their rather dissonant harmonizations. In spite of RCA's
optimistic heading, "two high-spirited
pleasures," the music isn't really that
easy to take in. Let's not over -do the
optimism!
I have the curious impression that
young John Browning, the pianist,
knows these works a lot better than
-
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Classical Record Reviews (continued)
the members of the orchestra, which is
supposed to have specialized in Prokofieff all these years. There are many
surprisingly sloppy bits of orchestral
ensemble (surprising, that is, for the
Boston Symphony) in the admittedly
difficult orchestral backing. Whereas
Browning cheerfully whangs forth
the trip-hammer piano music with the
greatest of aplomb. Could it be, that
this orchestral weakness is a symptom
of poor rapport between orchestra and
conductor? Leinsdorf has since left the
Boston, in something less than a state
of bliss.
-
r
A companion disc, LSC 2897, contains the other two Prokofieff concerti.
Performance:
B-
Sound: B
Daniel Barenboim Conducts Mozart Symphonies (No. 32 in G; No. 35 in D,
"Haffner"; No. 38 in D, "Prague." The
English Chamber Orchestra.
Angel S-36512 Stereo ($5.79)
Double -threat Daniel Barenboim is
a young pianist who is also a young
conductor; like many of the new generation, he finds a single musical role
too small, and aspires towards the
eighteenth century all-around musician type. In not too many more years,
most of our conductors will be performers as well, and often composers.
The three Mozart Symphonies,
No. 32, not often heard, and the other
two very familiar, are given a tasteful
and well balanced treatment a bit on
the chaste side, as though to lean over
backwards from those juicy renditions
(with very large orchestra) that used
to be standard from the older conductors. I don't mind the chasteness; what
seems more questionable is a curious
slurring of detail work. In Mozart, the
.-.-.i:-ir./i,r./ip.iiii-i/./i//firiii,vi-vi-ii.f.r.1v.fii,lu
The queen of Instruments
EDWARD TATNALL CANBY
One of E. Power Biggs' happiest
experiments for Columbia Records,
this last year or so, has been his
enthusiastic recordings on the pedal
harpsichord, a mammoth livingroom instrument with two regular
finger keyboards in the usual lap high location plus a complete lower story mechanism lying underneath,
on the floor, a case full of resounding heavyweight strings and a regular organ foot pedal board to operate
them. Seated on this instrument's
bench, the organist plays with all
his hands and feet, exactly as on a
pipe organ. And E. Power Biggs, of
course, is an organist. So was J. S.
Bach. And Bach also owned a pedal
harpsichord.
The interesting thing about this
now rare and slightly impractical
home -type instrument is its very
close relationship to the organ of
Bach's day. In fact this was its
entire raison d'être.
There have never been more artfully sonorous organs built than in
the Baroque era, as most of us now
know by virtue of our own ears and
record players. But not matter how
big, with no matter how many key-
boards-up to four-and dozens
of
complete stops, every organ had to
be pumped up by hand. The organist needed muscular assistance,
sometimes with relays of pumpers
working on enormous multiple bellows. Under such circumstances, no
player could afford to muse along in
a revery of improvisation, or compose (like the saintly César Franck)
by the hour while the pumping
crew puffed away to keep the pressure up and ahead of the leaks.
The only comparable expert that
I can think of in our present world
is the air -coupled deep-sea diver
-
Iha/i.Ji.he/%Ji.
whose life depends on a hand pump
at the surface. Even he is now out
of date.
Moreover, in Bach's day organs,
as now, were in churches, but those
edifices were unheated in winter,
even during the four-hour services
that were common on Sundays.
With so much cold weather in the
year, and human pumpers hard to
come by, how could a man like Bach
do his vast quantities of musical
homework? At home-on the pedal
harpsichord.
Thus this somewhat ponderous
home instrument (in terms of livingroom space) was an organist's
dream of convenience. It could be
played as an organ, with feet and
fingers, but without pumper assistance, in privacy and at leisure. The
organist could even "register" his
music; for the harpsichord has
"stops" like the organ, if fewer and
with less variety. Most important,
the vital aid of his two feet in addition to ten fingers allowed solo performance of music that was totally
impracticable on any other solo instrument but the organ itself-the
king of all the instruments then
available.
Mr. Biggs is an irrepressible humorist as well as an ever -zestful investigator into organ matters. His
first record of the pedal harpsichord
(built especially for him by John
Challis) was, predictably, the music
of Bach. From there, however, he
turned to high comedy booming
out such oddities as Chopin and the
Schubert "Marche Militaire" with
an effect somewhat like a circus
steam calliope. That record was
quite delightful. I once went so far
as to use it for background music in
a very zany home movie.
The newest Biggs pedal -harpsichord disc is again serious, and
again Bach. Very properly, since
Bach is the best known name di-
-
rectly connected with the instrument. The six Trio Sonatas, indeed,
are cryptically subtitled "for two
keyboards and pedals," which could
mean the organ but even more likely
indicates the pedal harpsichord
that Bach is known to have used.
Nothing, as usual, can be proved.
But the sound of the Trio Sonatas,
three on each of two Biggs records
(plus an extra concerto to round
each disc out) , is highly convincing
on its own. The music is ideal for
the massive three -voiced harpsichord effect, the two upper melodic
lines each on a finger keyboard and
the bass line solidly boomed out on
the massive strings of the pedal section. For those who enjoy the big,
"walking bass" of so many Bach
works, this novel harpsichord sound,
far more solid than a mere hand played instrument, is not to be
missed.
It remains merely to say that
E. Power Biggs, though occasionally
a rather uninspiring player, is capable of rising to new heights when
his favorite enthusiasms are involved. His playing of these Trio
Sonatas is really first rate, for the
most part carefully phrased and the
registration on the various hand played stops and the sonorous
strings of the pedal bass unusually
imaginative and lively. Don't ever
underestimate the Biggs potential.
On this counterfoil to the great King
of Instruments
which we might
properly call the Queen of Instru-
-
ments-Biggs and Bach make a fine
team.
Bach on the Pedal Harpsichord. The Six
Trio Sonatas. Vol. I, Nos. 1-3; Concerto in G after Johann Ernst. Vol. II,
Nos. 4-6; Concerto No. 2 in A Minor
after Vivaldi.
Columbia MS 7124, 7125 ($5.79 ea.)
Performance: A
-
Sound: A
-
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88
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Our speaker is now
a household word.
more crystal-clear is the phrasing and
articulation, the better is the musical
impact.
Performance:
B-
Sound: B
Three Tchaikowsky
Symphonies
Tchaikowsky: Symphony No. 1 ("Winter
Dreams"); No. 2 ("Little Russian");
No. 3 ("Polish"). U.S.S.R. Symphony
Orch., Yevgeny Svetlanov.
Melodiya Angel
SR
40057 stereo ($5.79
One of the best aspects of the LP
record is its persuasiveness as a medium for complete collections-like sets
of books all bound in the same covers.
The three early Tchaikowsky symphoñies don't often appear on concert
programs; we know the last three very
much better. But in LP collector's form
they are powerful and useful additions
to the basic Tchaikowsky repertory,
not only to fill out the complete list of
six symphonies but as interesting
sources for the later music, throwing
much light on it-and, last but hardly
least, as worthwhile music in their own
right.
The first three symphonies sound
like scaled -down models for the last
three. They have all the familiar features, but in a lower relief; the "big
tunes" are not quite as catchy, the
skillful orchestration is no less professional but is put to less effective dramatic use, the noise and bombast are
precisely as in the later works but,
again, with a more diffuse impact.
Not by much. Tchaikowsky was the
very model of a total professional and
there is not a note anywhere that is
out of place, not a trace of youthful
clumsiness. Even the style is already
totally Tchaikowsky-you can recognize it in an instant.
Good, authoritative Soviet performances, nicely recorded in very adequate, if slightly old fashioned, stereo.
Performances:
B-
Sound: B
Sibelius Back -to -Back
Sibelius: Symphony No. 2. Antol Doratil
Stockholm Philharmonic Orch.
RCA Victrola VICS 1318 Stereo ($2.50)
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The Sibelius Second was once one
of the big Romantic -modern repertory
concert pieces, and in many a live symphony concert series it still is. But,
alas, present-day musicians have lost
the Romantic touch and they often
flounder in this sort of music, unless
they have a "maestro," young or old,
who can teach them how to play
the way Beecham, Stokowsky, Kousse-
it-
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89
Classical Record Reviews (continued)
vitsky made the music sound within the
memory of plenty of us.
Not Dorati. His is an accurate performance via a good orchestra; nothing
is smeared, blurred; there are no sour
notes. But the spirit of the music, the
intention of the superb orchestral
effects, is incredibly faulted. The music
is parrotlike, point after point missed
cold. It is as though one were reading
Finnish out loud without understanding a word. Such an expressive and
dramatic idiom, too, even if dismally
old fashioned, and so marvelously written for playing! I was appalled and
fascinated.
If you are an old Sibelius fan you
will be much disappointed. If you are
new to that skillful composer of big
Romance, this recording is a poor way
to get to know him.
Performance: C-
Sound: B
Sibelius: Symphony No. 2. Sinfonia of
London, Tauno Hannikainen.
Crossroads 22 16 0026 Stereo ($2.49)
Yes, it's conducted by a genuine
Finn, out of Sibelius -land; and the
English (the orchestra) have always
been the foremost champions of Sibelius. But I found this performance
correct and dull. It is accurate enough
but somebody the conductor just
doesn't understand what it is all about,
misses the grand tensions, the climaxes, the passages that are supposed
to be supremely distraught, or grandly
triumphant. Definitely, I wouldn't
want to recommend this as a model for
those who are curious as to what makes
Sibelius tick.
-
Performance: C+
-
Sound: B
Ormandy/Bernstein in Space
2001-A Space Odyssey; Aniara-An Epic
of Space Flight in 2038 A.D. Ormandy
Philadelphia Orchestra, Bernstein N. Y.
Philharmonic, Gregg Smith Singers,
Added Electronic Effects by Morton Subotnik.
Columbia MS 7176 Stereo ($5.79)
Yeh, yeh, we know all about it. Tie-in
publicity and all that. Frankly, I found
this record a pain in the aural neck,
and not because the individual segments are necessarily "bad." It is just
too, too contrived, for cash -in purposes.
You've probably seen "2001" by this
time. If not, you'll find when you do
that the electronic music (Ligeti) and
the several "classical" items, such as
"Zarathustra" of Richard Strauss and
"Blue Danube" by Johann S., blend
remarkably well into the unusual picture with its stunning combination of
space -spectacle and everyday normality. But to hear these items excised
and separate from the film is another
matter, especially in the uncomfortable
tape -editing synthesis here displayed.
They've simply taken the war-horses
out of the Columbia catalogue and
spliced 'em together, along with the
electronic (and part -live) Ligeti items,
the whole smeared up with an overlay
of electronic bridge music by Subotnik.
Ghastly, I say. But you'll maybe like it
as trick background Musak.
As for the Blomdahl "Aniara," a selfstyled space opera, that also is a bit of
happy publicity coincidence. (Imagine
it, only 37 years apart!) The Blomdahl
was out a good while ago on records
and I found it pretentiously old-fashioned in spite of its super -modem exterior, all electronic hoopla of the sort
now too familiar right and left. So you
can have that side as well, for your
Musak.
(But do see the movie-and also,
afterwards, go out and buy the tie-in
book, which oddly enough goes a long
way to explain the background of the
confusing and controversial last portion of, the film.)
Electronics and Percussion-Five Realizations by Max Neuhaus.
Columbia MS 7139 Stereo ($5.79)
No matter how far-out, avant garde
art these days tends to fall as rigidly
into stylized schools as far-out politics.
In five seconds you will know that this
record belongs to the special school
that goes in for fragmented blips, plops,
oozes of sound, minus beat and minus
"tunes," much of the material being
pregnant silence. Decidedly a school of
thinking, though many composers belong to it, each in his own way. This is
also the school of the free -form "score"
-which merely lays down options for
performance that assure no two versions of ever being the same. Like, for
instance, the score here which is on a
single page which may be read "with
any edge up," or another score that is
circular and can begin at any point,
moving either clockwise or counterclockwise back to the beginning. Still
another "score," by that old-time
shocker John Cage, is realized here
via mikes set in front of loudspeakers
to produce random (but controlled,
within the set limits) squawks and
howls of electrical feedback! Ouch.
Lots of stimulating ideas here and a
vast quantity of plicks and plops and
gurgles, worth listening to if only as an
exercise for the ear in precision sonics
What else is any music, after all?
Performances:
?
Sound: B
90
Benny Goodman/Bartók
Bartók: Excerpts from Microkosmos; Contrasts. Bartók, Szigéti, Goodman (1940).
Odyssey 32 16 0220 Mono ($2.49)
Bela Bartók himself plays some of
his many "Microcosmos" piano pieces
on side 1; Bartók, Benny Goodman and
Joseph Szigéti play the Goodman -commissioned "Contrasts" for piano, clarinet and violin, on Side 2, these being
reissues of notable 1940 78 -rpm recordings-I own the original "Contrasts"
album, and once reviewed it.
For pianists, especially, the Bartók
piano renderings are good listening and
instructive. Nothing very difficult for
today's ears, and lots of Hungarian Bulgarian folk tunes to help. "Contrasts" is a wry, dry, astringent piece
with an ever so delicate sense of irony,
a dusty feeling of jazz, that fits Benny
Goodman's clarinet perfectly. Very dissonant, but very expressive too. The
recording is clean enough, but lacks
highs. The clarinet comes through best.
Performances: A
Far East
Sound: C+
. , .
and West
Messiaen: Turangalia Symphony.
Takemitsu: November Steps. Toronto
Symphony, Ozawa.
RCA Victor LSC 7051 (2) stereo $11.58)
Messiaen's enormous late -Romantic
symphony in modern idiom dates from
the 1940s and is the biggest, most blatant sound -blast on a very high level)
I've listened to for many a month. For
all its skillful complexity and its extreme dissonance, for all the whoops
and wails of the Ondes Martinot (a
French electronic instrument), for all
its immensity of physical size and of
length-ten movements on three LP
sides
found it overblown and, in
places, just plain corny (in a high level
way). It hasn't a tenth the subtlety of
Mahler's big music, nor any of the originality. It goes very well with such as
the much -vaunted Penderecki, or the
more monumental pieces by Carl Orff.
But it makes for marvelous hi fi, I'll
have to admit.
By contrast, the spare, sparce "November Steps," by a Japanese, combining two ancient traditional Japanese
instruments with a "Western" instrumental ensemble, is quite beautiful. The
flute tones and the twang sounds are
of terrible intensity, depending much
on silence, on sudden bursts of ferocity.
The orchestral dissonant background is
used only a few times, and blends perfectly. Terrific, particularly for young-
-I
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NOVEMBER 1968
er listeners who like the new Oriental
slant to our music.
Performances: A
Sound:
A-
Flower Dance. Japanese Folk Melodies.
The Noday family and others.
Nonesuch H-72020 stereo ($2.50)
One can never be quite sure how to
judge the music of another culture. I
can only say that, inside a charming
cover (a line drawing adapted from
the ex -Checkmate stylings) there was
music that struck my Western ear as
sort of uninteresting-but how wrong I
could be. The music is all -instrumental,
consisting
of
plucked -instrument
sounds and the sounds of flute -like instruments. It has, to be sure, a fascinating monotony-it is all the near -key
of G minor, or the modal Japanese
equivalent. There is near -harmony, but
you'll hear no outright chordal passages; the music is not corrupted (as
some is) by Western influences and
TV -style harmonizations.
Excellent hi-fi close-up recordings,
fit for the fanciest listening systems.
The record is part of Nonesuch's wideranging Explorer Series.
Performance:
Sound:
Shih-Kun, Pf. "The Butterfly Lovers"
(Concerto for Violin and Orch.). Shen
Yung, VI., Chinese Conservatory Orch.,
Fan Cheng -Wu.
Everest 3212 Electronic Stereo ($4.98)
A fancy title but a very sad content.
As the notes say, this is music "for
the masses" (and it seems to emanate
from China, though just how I cannot
imagine). If so, then the Chinese
masses are getting not Chinese pap
but watered-down Western. The stuff
is perfectly awful, full of a pathetic
pseudo - Hollywood
pretentiousness,
aping the very worst of sleazy Western
music without even the beginning of an
understanding-even of our worst.
Yet
the instrumentalists, soloists
and orchestra, are highly competent.
They play like Western pros! Just goes
to prove that you can always export
a muscular artistic skill, but the content that goes with it is something else
-
again.
Keep in mind, incidentally, that the
Russians first imported Western music
as far back as the sixteenth century
and have been acclimatizing it ever
since. Not so the Chinese. It's new for
them.
Sound:
want to buy
the Uher4000-L
when they can have
the same thing in stereo?
A-
Chinese Classical Masterpieces. "Youth"
(Concerto for Piano and Orch.). Liu
Performances: B
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The Uher 4400 contains every one of the great features of the 4000-L... in stereo. Therefore its reproductive capabilities are limitless. By hooking it up in
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NOVEMBER 1968
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ences no matter what kind of aggregation or repertory may be involved. This
set offers a mixture of pop standards:
Yesterdays and Too Late Now, Montgomery's own Missile Blues and
Jazz
Jingles, and Monk's 'Round Midnight,
Ellington's Salin Doll, Horace Silver's
Ecorah, and Benny Golson's Whisper
Not. Sound and stereo are both quite
satisfactory without, of course, beginning to approach the brilliance of the
newer sets.
Blues
Performance: A
BERTRAM STANLEIGH
Wes Montgomery Legacy
The Best of Wes Montgomery, Vol. 2.
Verve Stereo V6-8757
When one has recorded as much as
\Ves Montgomery did in the mere nine
years that he was a national figure on
the jazz scene, it's a bit hard to crowd
all of an artist's major achievements
onto a single album. Recognizing that
volume 1 omitted a number of likely
"best" candidates, Verve has repackaged a second set of numbers from
earlier collections. This time including Bumpin' and California Dreamin',
both title tunes from sets that date
back a year or two. The only problem
with this reshuffling technique is that
it probably won't stop until all of the
old Montgomery material has been reissued in every possible combination.
But aside from the obvious commercial considerations, this set does contain some of Montgomery's strongest
late work, with large instrumental
backgrounds. And the sound is simply
splendid.
Performance: A
Sound: A
Wes Montgomery Trio: 'Round Midnight.
Riverside Stereo RS -3014
A reissue of the original Riverside
first recordings of Montgomery, now
being distributed by ABC Records, this
set provides a fascinating contrast to
the Verve reissues noted above. Melvin
Rhyne, organ, and Paul Parker, drums,
function as close collaborators, playing
real jazz. This is very different from
the slickly adroit string backgrounds
by Claus Ogerman, Oliver Nelson, and
others on his later, more commercial,
releases, but Montgomery was one of
those rare jazz musicians who produce
exciting, meaningful musical experi-
Jazz
Sound:
A-
"Greats" on Riverside
When the first reissues of the Riverside label were released under the auspices of ABC Records, it was evident
that they had been culled from that
portion of the Riverside catalog that
was primarily of interest to mainstream
and modern jazz fanciers. Bill Evans,
Thelonious Monk, Wes Montgomery,
Johnny Lytle, Sonny Rollins, and
Yusef Lateef were among those performers whose important contributions
to Riverside were happily re -instated.
A second ABC release of treasures
from this same source includes additional Monk, Evans, Montgomery, and
Lytle, and it gives us, as well, Art
Blakey, Max Roach, Tad Dameron,
Milt Jackson, and the less familiar recordings of Joe Albany and George
Russell.
Missing from the ABC -Riverside reissues are all of the early Riverside
transfers from 78s of classic jazz that
originally graced the Gennett catalog.
Now these are also coming out in new
transfers on a new label, Orpheum.
For its first release, on its "Jazz Legend Series," Orpheum has issued five
albums "rechanneled for stereo" that
feature the New Orleans Rhythm
Kings, Bix Beiderbecke, Jelly Roll
Morton, Muggsy Spanier and King
Oliver's Creole Jazz Band. The later
item has kept its somewhat deceptive
title The Great Louis Armstrong, 1923.
Louis, as every student of jazz history
knows, had joined the Oliver group for
its legendary season at Chicago's Lincoln Gardens, and his first records
were cut in 1923 while he was playing
second trumpet to the great King
Oliver.
All of the material on these five albums was originally recorded by the
Starr Piano Company, which made
Gennett records. With the exception
of two numbers recorded in New York
in 1924 by Beiderbecke and George
Brunis, all of the originals were waxed
in Richmond, Indiana, between 1922
and 1928. These were not modern electrical recordings. Indeed they were not
even the best of acoustical recordings,
and it is plain that these new reissues,
even "rechannelled for stereo," do not
represent any startling improvement
in sound quality over the Riverside LPs
of the late Forties and early Fifties.
They fill a gap in our historical archives, and their reappearance is most
welcome, but I have reservations as to
whether these particular reissues are
as good as they might be. It is no more
than suspicion on my part, but I have
a hunch that these new masters were
cut from the original 78 -to-tape transfers made by Riverside some years
back. A lot has been learned since that
time about how to get the most from
an old 78.
Even if there may be more on these
platters than can be heard in the present transfers, there is still a lot of good
listening to justify their return to the
catalog. While some of the material
was duplicated by other early record
companies, the Muggsy Spanier and
Bix Beiderbecke sets offer rare early
performances by these two trumpeters
that do much to place their careers and
later achievements in proper perspective. The Jelly Roll Morton piano solos
are also documents of value, and unlike some of the other sets in this series,
the Morton sessions of 1923 and 1924,
at which this dozen numbers were recorded, have been properly referenced,
even though details of the original
discs are omitted. If Orpheum has
plans to bring out more of the early
Riverside cache, we hope they will
make an effort to achieve a brighter,
closer sound and present more complete documentation. There is probably no chance that they could be cajoled into leaving these mono recordings in their original single -channel
perspective. Orpheum's "rechanneling"
has been done without resorting to
very extreme devices. As a result, there
is a slight difference in balance between right and left channels when
heard alone, but the final blending of
the two channels results in nothing but
a slightly tubby mono sound.
The Great Muggsy Spanier
Orpheum Stereo 101
Performance: A
Sound: C
The Great New Orleans Rhythm Kings
Orpheum Stereo 102
Sound: C
Performance: A
AUDIO
92
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NOVEMBER 1968
The Great Jelly Roll Morton
Orpheum Stereo 103
Performance: A+
Sound: B
The Great Bix Beiderbecke
Orpheum Stereo 104
Performance: B+
Performance: A
Sound: C
Henrique
and
Sound: C
Walter
Wanderly:
Popcorn.
Verve Stereo V6-8734
As a delightful set of Bossa -jazz or
as a stereo spectacular, this set is a
knockout. Without resorting to ear blasting volume levels, Messrs. Henrique, guitar and voice, and Wanderly,
organ, abetted by flute and percussion,
turn in some of the crispest, close up,
musically natural sound
want in his living room.
happiest when Henrique
ing in Portuguese rather
anyone could
Frankly, I'm
does his sing-
than English,
Norman Eisenberg said in
Dick Hyman and "The Group": Sweet
Command Stereo
Jazz a la Organ
Luiz
`HIGH
RS
933 SD ($5.79)
Playing organ and clavinette, Dick Hyman whips up a bit of a storm with the
able assistance of Bobby Rosengarden's
percussion and Bob Haggart's bass.
This is richly melodic jazz that's exciting both for the technical prowess
of the performers and the clear, bright
sound of the recording. It's a rather
small aggregation for a Command record, but it has as much big sound on
it as if it held a full orchestra.
Performance: B+
Performance:
A-
Sound: B
David Newman: House of David. Atlantic
Mono 14899 ($4.79)
Tenor saxophonist David Newman
was a leading light of the Ray Charles
band in the early sixties. After a departure from the jazz scene for three and -a -half years, he returns to discs
with a solo set of attractive mainstream statements. With the sure support of Koussie Gardner, organ, Tod
Sound: A
Miscellany
T -Bone
Dunbar, guitar, and Milt Turner,
drums, Newman makes clear that his
Walker: Funky Town. Blues Way
return is a welcome one.
Stereo BLS -6014 ($4.79)
A guitarist -singer with a strong, rocking drive and a deeply felt personal
Performance: A
Sound: A
FII LI'rv':
'SURROUNDANO CONQUER.... the Bose 901 strikes me as the
best -sounding speaker system in its size and price class l have yet
auditioned. Indeed it rivals many systems built to larger dimensions and/or costing considerably more. In its midrange and highs
-for clarity, full range, wide dispersion, open and natural soundit is unsurpassed by anything I've heard.... the 901 system is the
closest approach to the concept of "sound conditioning" of a listening room yet encountered in a commercially available, competitively priced product.... Add to these virtues the utterly clean
wide -range response of a 901, its neutral, well-balanced transparent quality on all program material, and you feel you've made
some sort of stereo discovery. And it doesn't pall either: you can
listen to this system for hours on end without getting listener fatigue-if your own response to it is like ours, you'd be reluctant to
turn it off and go to bed"
Julian Hirsch said in `Stereo Review':
'After a couple of months of living with a BOSE 901 system, lam
convinced that it ranks with a handful of the finest home speakers
of all time.... The BOSE 901 had an utterly clean, transparent, and
effortless sound Its clarity and definition when reproducing complex orchestral passages were, in the writer's opinion, unsurpassed
by any other speakers he has heard... Its low -bass response was
difficult to credit to such a compact system. It had all the room
filling potency of the best acoustic -suspension systems, combined
with the tautness and clarity of a full -range electrostatic speaker
The spatial distribution, which brings an entire wall alive with
sound contributes greatly to the sense of realism.... I must say
that I have never heard a speaker system in my own home which
could surpass or even equal the BOSE 901 for overall 'realism' of
-
sound"
Sound: A+
Sweet Soul
The Great Louis Armstrong, 1923
Orpheum Stereo 105
Performance: A
message, Walker is heard in a collection of his own compositions with a
band that wastes little time on subtlety
or low level passages. Walker's fine
guitar solos are over -amplified, as is
the electric organ, and the reeds in the
band rarely drop below a fff shriek.
There is much fine music -making on
this record, and the engineering is not
bad, but the combination of continuously loud performance levels and
close-up miking make this release a bit
painful for extended listening.
and I would have been grateful if
Home on the Range hadn't turned up
smack in the middle of side 2, but
there's so much brisk, up -spirited
music making here that such reservations really amount to quibbling.
We Say:
Out of 12 years of research has come a deeper understanding of what a loudspeaker is trying to accomplish in reproducing a musical performance in your
living room ... and a better technology to accomplish it.
The
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BOSE 901 incorporates four major advances in speaker design, covered by patents issued and pending.
The proper balance of direct and reflected sound, as measured in the concert hall.
The use of multiple, same -size, full -range speakers, internally coupled, to
eliminate audible resonances and distortions inherent in woofers, tweeters
and crossover networks.
Active equalization for utterly smooth power output throughout the
spectrum.
A new and different scale of measurement for a new and better concept of
speaker function. The 901 radiates a flat total power output into the room,
whereas the conventional speaker is limited to flat frequency response on
axis.
You can hear the difference now.
THE
OW
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Check No. 93 on Reader Service Card
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NOVEMBER 1968
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standout cut is a really beautiful instrumental version of the talented Jim
Webb's "MacArthur Park." Top-notch
stereo reproduction.
Light
Listening
Performance: B+
Sound: A
Music from "The Young Girls of Rochefort." Composed and Conducted by
Michel Legrand.
United Artists UAL-3662/UAS-6662
STUART TRIFF
($4.79)
Music from "Man of La Mancha." Joe
Sherman and The Washington Squares.
Columbia CS -9657 ($4.79)
Though it's not likely to suit all
tastes, this is a decidedly fresh and
novel approach to an instrumental version of a Broadway show score. Arranger Sherman has blended Spanish
rhythms and Dixieland to give Mitch
Leigh's music a new dimension; it
works beautifully and the renditions
are truly exciting, from the title tune to
the popular "The Impossible Dream."
Clean, sharp stereo definition.
Sound: B+
Performance: B+
Strings Latino: Edmundo
Ros and His
Or-
chestra.
London Phase -4 Stereo
SP-44107
($5.79)
A mixture of old and new latin tunes
in the typical Edmundo Ros manner,
meaning an album of pleasant listening, albeit a bit dated (echoes of Xavier
Cugat in his heyday). Nothing oldfashioned about the reproduction,
though, being quite up to the standard
we've come to expect of Phase -4. The
tunes include such Ros specialties as
"Rhumba Rhapsody," "Green Eyes,"
and "Delicado," with the old maestro
supplying the vocals on "A Man and a
Woman" and "Thank U Very Much."
Performance: B
Sound: B+
"Angel of the Morning" and Other Hit
Themes for Young Lovers. Percy Faith
Orchestra and Chorus.
Columbia CS -9706 ($4.79)
Another Percy Faith offering resulting from his apparently successful formula of "in" theme albums, dedicated
to the Younger Set. This is a collection
of current favorites in warm, intimate
renderings by silky Faith strings, augmented by an all -femme vocal group.
Included are "Scarborough Fair/Canticle" and the "Mrs. Robinson" theme,
both from the movie, "The Graduate";
and two Burt Bacharach tunes-"Do
You Know the Way to San Jose?" and
"This Guy's in Love with You." The
As is usually the fate of most sequels,
"The Young Girls of Rochefort" suffers by comparison with Legrand's
score for "The Umbrellas of Cherbourg." The former, however, has much
to recommend it, and the composer's
musical creativity and melodic invention are still head and shoulders above
the output of most of today's tune -
smiths.
Unless you share Legrand's excessive fondness for vocal writing in the
instrumental "do -be -do" technique,
you'll find this orchestral version of the
score more enjoyable than the original
soundtrack recording. The arrangements here are, of course, by Legrand, and particularly fetching is the
"Theme du Concerto," a tongue-incheek opus inspired by the stereotyped
Hollywood cinema concerto. Bright
and effective stereo.
Performance: B+
Sound: B+
Don Shirley in Concert. Don Shirley Trio.
Columbia CS -9684 ($4.79)
As an old Don Shirley fan, I've often
lamented this superb pianist's relative
inactivity in the recording studios.
Now, Columbia has had the good sense
to make a "live" recording of his recent
Carnegie Hall concert and the result is
in every way a notable event. Sensitively supported by the outstanding
work of cellist Gilberto Munguia and
bassist Henry Gonzalez, Shirley applies his classical, chamber music approach to an artfully -selected group of
popular standards.
The program includes a seven-minute sonata version of Vernon Duke's
"I Can't Get Started" (with some exquisite cello passages), and a scherzo like "I Feel Pretty," lasting little more
than a minute, plus lovely tone poem
treatments of "Yesterday," "I Cover
the Waterfront," "By Myself," and the
touching "Water Boy." Very commendable sound for an "on -location"
job. Run
don't walk, friends, and
listen to a magnificent artist in one of
the year's outstanding releases!
-
Performance: A+
Sound: B+
94
Jack Jones: If You Ever Leave Me and ten
other songs. Arr. & cond. by Marty Paich.
RCA/Victor LPM/LSP-3969 ($4.79)
Easy listening all the way as Jack
Jones swings gently through his newest collection of songs, mostly of recent
vintage, with a couple of oldies added
for good measure. He brings an ingratiating warmth and intimacy to
such tunes as "Goin' Out Of My Head,"
"By the Time I Get To Phoenix,"
"The Letter," and "Baby, Don't You
Quit Now."
Also included, is "There Comes a
Time," from a musical that blitzed in
London not long ago, called "The Four
Musketeers." Fine backings by Marty
Paich.
Performance: B+
Sound: B+
Discovery: Larry Adler, harmonica; with
Morton Gould and his Orchestra
(George Gershwin's "Lullabye Time"
plus music by Porter, Gould, Rodgers,
Kern, Arlen, & Gershwin). RCA Victor
LM/LSC-2986 ($5.79)
For his recording debut on RCA,
harmonica virtuoso Larry Adler has
collaborated with conductor-arranger
Morton Gould in this album of esoteric
material, garnered from the musical
trunks of some of the elite among
American show composers. When musical compositions remain in the form of
unpublished manuscripts and are relegated to a dusty attic by their creators,
it is usually for a good reason ... a
reason which this collection (with one
exception) makes all too clear.
Fortunately, the Adler -Gould explorations have uncovered one fascinating item that makes this disc worth
having-the 8 -minute Gershwin work
called "Lullabye Time." The version
heard here is Morton Gould's tasteful
and wholly appropriate transcription
for harmonica (playing the first violin
part) and string orchestra. The performance is beautiful; played with sensitivity, warmth, and obvious affection.
It's a pity to report that after "Lullabye Time," this collection goes far
astray musically and artistically. The
other numbers, though pleasant
enough, and perhaps even a few notches
above most of the pap that passes for
popular music today, are really not distinguished.
Performance: A ("Lullabye Time")
C (Everything else)
Sound: B+
AUDIO
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NOVEMBER 1968
Recorded
Tape
Reviews
BERT WHYTE
Bernstein/Watts:
Brahms Piano Concerto
Brahms: Piano Concerto #2 in B Flat.
Andre Watts, piano. Leonard Bernstein
cond. the New York Philharmonic
Orch.
Columbia MQ999, 4 tr., open reel, 71/2
ips ($9.95)
Maybe you have noticed that there
have been 'quite a few recordings of the
Brahms B -flat concerto issued lately.
No one seems to know why this sudden interest
there isn't any kind of
anniversary or Brahms festival in
sight. In any case, this reading by
Watts and Bernstein is one of the latest and, from many aspects, one of the
most attractive.
...
For one thing, young Andre Watts is
possessed of a phenomenal technique.
The difficult runs, octave progressions,
trills, he tosses off with almost insouciant ease. Yet for all his Horowitz -like
proficiency, he is an extraordinarily
communicative musician with a maturity that has come at a very early
age. His is a bravura reading, intensely
passionate and poetic. Yet his traversal
of the third movement was exceptional
for his handling of texture, his clean
phrasing, the warmth, and depth of his
involvment, the utter elegance of his
playing. In this concerto, where the orchestral part has considerable weight,
Bernstein's accompaniment (while
generally sympathetic) is almost too
intense. He allows his sense of drama
full sway and, at times, comes close to
overwhelming Watts. If you can walk
this kind of ragged edge ... indulge in
this "musical brinkmanship," the results can be very exciting.
As to quality, this is a recording
notable for superb balance. Balance between piano and orchestra, and between orchestral choirs. Left/right
directional effects were nicely proportioned with the piano solidly in the
phantom center channel. Frequency
response wide with a good solid bass.
Dynamics were wide, transient re -
sponse excellent, as attested by the
bright, clean sound of the piano.
This is another of those recordings
which must be played at a fairly high
level for best balance. At this kind of
level, the hiss was somewhat obtrusive.
There was also some print -through
and some occasional crosstalk. On an
overall basis this recording is not as
sonically spectacular as some others I
have heard ... and I have yet to audition several other new recordings of
this concerto. Nevertheless, with Andre Watts' altogether ingratiating
performance and the thoroughly respectable sound, this must be reckoned
as a solidly competitive recording that
will appeal to many people.
The Versatile Von Karajan
Liszt: Les Preludes; Hungarian Rhapsody
No. 2. Smetana: Vysehrad; Die Moldau.
Herbert Von Karajan Cond. the Berlin
Philharmonic.
Ampex/D.G.G. DGC9037, open reel, 4
tr., 71/2 ips ($7.95)
This man Von Karajan is amazing
in his versatility. What a study in contrasts is represented on this tape ...
the rather pompous and overblown
"Les Preludes" gets a performance of
such majestic power as to make the
(Continued on page 96)
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NOVEMBER 1968
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piece newly palatable. The 2nd "Hungarian Rhapsody" is also powerfully
conceived, but the rhythmic aspects
are not neglected. "Vysehrad" is part
of Smetana's epic cycle, "Ma Vlast," as
is the much more familiar "Die Moldau." Both are given a beautifully
atmospheric and evocative reading,
featuring superb string work from the
orchestra.
There seems little doubt that the
combination of Von Karajan and the
Berlin Philharmonic has become something of a phenomenon. Certainly he
is one of the most recorded of today's
conductors, probably because of his
aforementioned versatility as well as
for his considerable personal magnetism and "box office" appeal. His income from recordings must be tremendous ... he has so many recordings
currently available I could fill this
entire column with them! The sound
he gets from Deutsche Grammophon
doesn't hurt either. It is rarely less
than first class and, in many cases, as
in this recording, quite outstanding.
Beautifully balanced and proportioned,
wide in dynamics, appropriate in
acoustic perspective, possessed of all
the stereo virtues, this is a winner in
every respect including top notch EX Plus processing.
Shostakovich: Symphony No. 10 in E
Minor. Herbert Von Karajan Cond. the
Berlin Philharmonic.
Ampex/D.G.G. DGC9020, open reel, 4
tr., 7'/2 ips ($7.95)
Shostakovich's 10th Symphony is
slowly becoming recognized as one of
his major works. It doesn't assimilate
too easily the first time around, but
subsequent auditions help to sort out
its complexities and you begin to realize what a powerful personal statement the composer has made.
It would seem that this is also one
of those "conductor's" symphonies, an
ideal vehicle for the aristocrats of the
baton. Hence there have been three recordings issued recently of which this
is in my opinion, by all odds the best.
It is obvious Von Karajan is enjoying
himself here, abetted by his magnificently responsive Berlin Philharmonic.
This is a very dynamic performance,
very intense and dramatic, a supercharged reading that demands an iron willed conductor who is a great technician and an orchestra of exceptional
precision. One has but to listen to the
propulsive energies of the boisterous
finale to appreciate the quality of
musicians necessary for such brilliant
playing.
The sound here is of huge, almost
overwhelming proportions. The acous-
96
tic perspective is fairly broad, miking
moderately close-up, the whole adding
up to that happy blend of orchestral
definition with presence that is so difficult to produce. Left/right directionality and center phantom channel combined to present an unbroken sonic
panorama of the orchestra. Balance
between the various choirs of the orchestra was superb. Dynamic range
was quite wide, excellent transient response. All was exceptionally clean
and a final bonus was the low noise
levels of this splendidly processed
EX -Plus tape.
Sibelius: Finlandia, Valse Triste, Swan of
Tuonela, Tapiola. Herbert von Karajan
cond. the Berlin Philharmonic Orch.
Ampex/DGG DGC9016, 4 tr., open reel,
7'/2 ips ($7.95)
Herbert von Karajan has always
been quite successful with the music
of Sibelius. In this recording he gives
us some outstanding performance of
these popular works. The Valse Triste
and the Swan of Tuonela are studies
in virtuoso playing, and the English
Horn solo in Tuonela is simply beauti-
performing these works, maintaining
that there are many differences. I feel
that at least as far as recordings are
concerned, it is mainly in matters of
sound quality that affords a basis for
comparison. The Grenadier Guards are
without question a "marching band"
and they perform these familiar
marches with great verve and commendable precision. The program is typical with such favorites as "El Capitan,"
"Semper Fidelis," "Washington Post,"
"The Thunderer" and, of course, the
inevitable "Stars and Stripes Forever."
The sound is excellent although
lighter in weight than the kind afforded
Fred Fennell in his Mercury recordings. Acoustics were not too spacious,
but the miking was nicely handled and
gave the music good presence. Good
directional qualities with adequate center fill. Ensemble well-balanced, projection good, except for the bass drum
which was a bit lacking in weight and
prominence. Other percussion quite
clean, brass and woodwinds nice and
bright. At moderately high-level playback, hiss and crosstalk were low, some
print -through noticeable.
ful.
Karajan pulls out all stops in his
rousing performance of Finlandia. It
has propulsion, nobility and, above all,
it is exciting. Tapiola receives one of
the best performances ever, very properly atmospheric with absolutely stunning string work by the Berliners.
The sound is superb, and appropriate to each work. The two quieter
works are clean and richly sonorous.
Finlandia and Tapiola have sound of
great power and presense. Some really
weighty brazen brass here, and strings
are almost searing in their intensity.
The acoustics were spacious and miking nicely handled for excellent depth
effects. Left/right directionality and
orchestral balances in general were
good. Dynamic range was exceptionally wide. Played at a fairly high level,
the hiss was low, almost no print through or crosstalk were noted. If you
like Sibelius, you can't go wrong' with
this recording.
"Marching Band"
Band of the Grenadier
Guards cond. by Major Rodney Bashford.
Sousa Marches:
London/Ampex LPL74103, open -reel,
tr.
4
71/2 ips ($7.95)
This is a fine recording of its type.
Although you might feel that if you've
heard them all, this doesn't apply to
band buffs, whose numbers are legion.
They make the fine distinction of a
marching band versus a concert band
Ormandy/Ives
Ives: Symphony No. 1 in D Minor; Three
Places in New England. Eugene Ormandy and the Phila. Orch.
Columbia MQ991, open reel, 4 tr., 7'/2
ips ($9.95)
One can dispute the merits of the
various conductors who have espoused
the cause of Charles Ives, in an endless academic exercise. Ormandy has
his faults, but I like what he does
with this music, especially his "Three
Places" reading. Perhaps I'm influenced by the splendid sonorities of the
orchestra. At any rate, I'll be hard to
convince that there is a better sounding version.
The Lighter Side
Is King: Ted Heath and His Music.
Ampex/London LPL74104, open reel, 4
tr., 71/2 ips ($7.95)
Swing
This isn't for those under thirty,
but if any of that breed would like a
sampling of what made their "square"
parents "blow their cool," this tape will
serve admirably. They are all here...
those numbers that will always be
equated with the thing called "swing,"
and so closely identified with certain
"big bands." "Flying Home," "One
o'Clock Jump," "Woodchoppers' Ball,"
"Sing, Sing, Sing" and eight other nostalgic flights back to the late '30's and
'40's make up the program played with
AUDIO
NOVEMBER 1968
appropriate swingin' style by Ted
Heath ... himself a refugee from that
era. The sound is typical Phase Four,
very live and BIG, with much exaggeration of directivity and reverb, but
nonetheless quite clean and of considerable impact. Pleasingly low hiss,
but some audible print -through and
crosstalk.
Joel Grey: "George
M!"
Columbia OQ1023, open reel,
ips ($7.95)
4
tr.,
71/2
This show received rave reviews, and
from the evidence here they were well
deserved. It has plenty of drive and
zip, Joel Grey is perfectly cast as the
brash George M. Cohan and the supporting cast would be hard to fault.
The Cohan songs are a virtual roll call
of Broadway. In spite of all these virtues, after awhile I found the songs
repetitious and the whole thing rather
dated. Heresy? Maybe so, or maybe
I'm not as old as is necessary to fully
enjoy this music. Good sound throughout, although I thought the voices
somewhat peaky. Excellent stage movement. Some print -through and crosstalk, but the hiss level was very low ...
in fact this is one of the quietest tapes
I have encountered.
Walter Wanderley: Kee-Ka -Roo.
Ampex/Verve VVC8739, open reel, 4 tr.,
71/2
ips ($7.95)
I don't know whether Kee -Ka -Roo
is the call of some jungle bird, or whatever. There is some sort of weird sound
that ties in perfectly with Walter Wanderley's exotic latin, yet jazzy rhythms.
As usual this group plays with its typical bouncy ebullient drive and almost
nervous propulsion. The sound is very
bright, recorded quite close-up, but
with just the right touch of reverb that
combines for excellent presence. Little
hiss, slight amount of print -through,
crosstalk no problem.
The Enoch Light Singers.
Ampex/Project
3 PJX 5021,
open reel.
4 tr., 33/4 ips ($5.95)
The Enoch Light Singers are not
identified on this tape ... which is a
shame, for they certainly deserve credit
for some excellent performances. They
sing with considerable expression, with
precise diction and are always articulate ... a refreshing change from some
of the dismal mumbling that passes for
choral work these days. As the title
indicates (and with justification for
once) this fine group sings such
"smash" hits as "It Must Be Him,"
"Love Is Blue," "I Say a Little Prayer,"
and "Up, Up, and Away." Eight other
reasonably current hits round out the
program, including a particularly attractive version of the "Ode to Billy
Joe." Good vocal/orchestral balance,
fine ensemble work. The reverb was
moderately applied and the miking
fairly close, adding up to good definition and presence. Hiss was moderate
at fairly high-level playback. There
was occasional print -through, almost
no crosstalk. Nothing earth -shaking
here, but a very pleasant tape, well
above the average of its type.
Hugo Montenegro: Music from "The
Good, the Bad and the Ugly," "A Fistful
of Dollars," "For a Few Dollars More"
Music to Spy By.
RCA Victor TP3-5052, open reel, 4 tr.,
33/4 ips ($9.95)
"The Good, the Bad and the Ugly,"
"A Fistful of Dollars," and "For a Few
Dollars More," is a trilogy of films
noted for their excessive and graphically displayed violence and gore. They
were also characterized by music composed by Ennio Morricone of Italy,
that caught the public's fancy and produced several hits. The music is rather
sensationalistic and filled with tricky
effects, that afford a field day for the
sound engineers. A super multi -mike
mix here with much spotlighting of instruments and deliberately overblown
reverb. A lot of it is pure corn, but one
cannot but admire the masterful recording job. Much the same can be
said of "Music to Spy By," a compilation of TV and movie themes reflecting the current emphasis on spies and
super -heroes. Thus we have music
from "I Spy," "The F.B.I." and "Get
Smart" along with "Thunderball,"
"Goldfinger" and the "James Bond
Theme," and others. The engineers
pull out all stops here and the result
is almost like a short course in modern
studio recording. Even with the restrictions of the 33/4-ips speed the
sound is ultra -brilliant, with razor
sharp definition and overwhelming
presence. Like olives, one must develop
a taste for this sort of thing ... for
those who are muy simpatico, this tape
should make them flip!
OTHER RECOMMENDED TITLES
Sergio Mendes/Favorite Things.
Ampex Cassette ALX58177 ($5.95)
Tony Mottola/Latin Love -In.
Ampex Cassette PJX55010 ($5.95)
Roger Williams/More Than a Miracle.
Ampex Cassette KTX53550 ($5.95)
Something New/The Glenn Miller Orch.
Epic 8 Track, N1810116 ($6.95)
Bobby Hackett/A String of Pearls.
Epic 8 Track, N1810114 ($6.95)
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7o,fron,es
COMPANY. INC.
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Phone: (612) 545-0401
Check No. 97 on Reader Service Card
AUDIO
97
NOVEMBER 1968
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AmericanRadioHistory.Com
LETTERS
Have you an
ear for music?
(Continued from page 16)
Electronic Organs
I like your article on electronic organs in the September issue of AUDIO.
Perhaps there's something I don't
understand about the various methods
of tone generation, but isn't ElectroVoice's system of engraving wave forms
on a stator plate a different method
that you didn't discuss? That's the invention of Dr. Jean Dereux. Or is that
method similar to the Compton's that
you mentioned?
JOHN R. EMBLEN
Then
your ears
pamperWith
SUPEREX
TOP-RATEST--13R
stereo -Phones
Complete with woofers, tweeters,
and crossover networks built into
each earphone. The experts say
"they're something special" and
they "deserve to be heard." Once
you've heard them you'll agree.
Ask your dealer for a demonstraWrite for Superes specification brochure and
reprint of ST -PRO -B review.
SUPEREX ELECTRONICS CORP.
1
tion. Approx. $50
RADFORD PLACE, YONKERS, N.Y.
10701
Check No. 98 on Reader Service Card
STATEMENT OF OWNERSHIP, MANAGEMENT AND CIRCULATION,
Title 39, United States Code.
Act of October 23, 1962; Section 4369,
Date of Filing, Oct. I, 1968; 2. Title of Publication, AUDIO; 3. Frequency of Issue, Monthly;
4. Location of Known Office of Publication, 134 N. 13th Street, Philadelphia, Penna. 19107; 5. Location of the Headquarters or General Business Offices of the Publishers, 134 N. 13th Street, Philadephia, Penna. 19107.
6. Names and Addresses of Publisher, Editor, and Managing Editor: Publisher, C. G. McProud,
134 N. 13th Street, Philadelphia, Penna. 19107; Editor, Arthur P. Salsberg, 134 N. 13th Street,
Philadelphia, Penna. 19107; Managing Editor, none.
7. Owner, North American Publishing Company, 134 N. 13th Street, Philadelphia, Penna. 19107.
1. J. Borowsky, 134 N. 13th Street, Philadelphia, Penna. 19107.
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or More of Total Amount of Bonds, Mortgages or Other Securities: None.
9. Paragraphs 7 and 8 include, in cases where the stockholder or security holder appears upon
the books of the company as trustee or in any other fiduciary relation, the name of the person or
corporation for whom such trustee is acting, also the statements in the two paragraphs show the
affiant's full knowledge and belief as to the circumstances and conditions under which stockholders
and security holders who do not appear upon the hooks of the company as trustees, hold stock and
securities in a capacity other than that of a bona -fide owner. Names and addresses of individuals
who are stockholders of a corporation which itself is a stockholder or holder of bonds, mortgages,
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the interests of such individuals are equivalent to percent or more of the total amount of the stock
or securities of the publishing corporation.
IO. This item must be completed for all publications except those which do not carry advertising
other than the publisher's own and which are named in Sections 132,231, 132,232, and 132.233,
Postal Manual (Sections 4355a, 4355b, and 4356 of Title 39, United States Code).
Average no. copies
Single issue
each issue during
nearest to
preceding 12 months
filing date
47.966
60.000
A. Total no. copies printed (Net Press Rut)
B. Paid circulation
I. Sales through dealers and carriers, street vendors and
counter sales
13.117
14,400
23,297
31,187
2. Mail subscriptions
36,414
C. Total paid circulation
45,587
D. Free distribution (including samples) by mail, carrier or
1.024
2,788
other means
37,438
E. Total distribution (Sum nf C and D)
48,375
2,000
1.784
F. Office use, left -over, unaccounted, spoiled after printing
9,625
Return Copy Privilege
8,744
E
net
press
rut
Total
(Suet
of
und
F-should
equal
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60,000
shown in A)
47,966
I certify that the statements made by me above are correct and complete.
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1.
1
Plainfield, Ind.
Author's Reply:
The Electro -Voice company has been
active in two distinct areas of the electronic organ market. When I prepared
my original books on the subject
(Sams' ABCs of Electronic Organs),
the company had only recently introduced the home models which featured
the chord coupling I described there,
using the lower keys of the manual,
with electronic oscillators and dividers
for tone generators.
These organs were discontinued a
couple of years ago and, knowing this,
I did not check with Electro-Voice
when I started to prepare the present
series. At that time I was unaware
that the company had more recently
entered the larger organ market, using
the type of generator to which you
refer for organs usually installed in
churches or public buildings. However,
I understand that they are now discontinuing this production also.
To answer the technical aspect of
your query, these larger Electro -Voice
organs used a scanner that worked very
similarly to the Compton. The difference was in the technique used for producing the circular tracks, which they
did under license from the French inventor you named.
NORMAN H. CROWHURST
Gold Beach, Oregon
Capacitor PC Mounting
Re your answer in February 1968
Audioclinic, the 4500 l,(,F, 50 V capacitors are most probably CG452U50D1's,
which are 2" diameter x 41/8" high.
This is a little big for printed -circuit
board mounting by the terminal posts.
The main point is, however, that normal practice is to use "mounting rings,"
which are a standard Mallory part,
cost 18¢ for this size, and provide a
wide, three-point mount. Sprague has
them also.
WALT FERRIS
Palo Alto, Calif.
98
AUDIO
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NOVEMBER 1968
ELECTRONIC ORGANS
(Continued from page 80)
Vibrato
A later installment will go into details about vibrato, but applying a
`wobble' to the' notes also relates to
the problem of frequency stability,
which we will consider here. If all
the tones aren't precise, wobbling
them a little, which vibrato does,
will disguise the error. Some of the
cheaper organs rely on this, to "get
away" with poor tuning stability.
But even if your tuning is perfect,
you'll want vibrato. An electronic
organ doesn't sound right without
vibrato, for most of the music you'll
play. Some church or cathedral type
music may sound right without vibrato, but you'll probably want
something more versatile than that.
This brings in the question of how
you'll get your vibrato. The idea of
vibrato by phase shift, introduced in
the previous installment, is very attractive, in theory, and quite possible. But it isn't easy, except at the
lower frequencies.
Suppose you phase -shift a lower
frequency, say, 55 Hz. Its period is
18 milliseconds. If this is advanced
a quarter of a period during half a
second, the average period will be
reduced and frequency momentarily
increased.
Half a second of the original frequency would contain 27.5 periods.
It will now contain 27.75 periods, or
the frequency will swing up to 55.5
Hz average, with a peak of about
55.8 Hz. In the next half second the
number of periods will be reduced,
so the frequency drops to about 54.2
Hz. Thus the nominal 55 Hz will
swing from 54.2 Hz to 55.8 Hz, or
3.2%, total of about half a semitone
(quarter of a semitone deviation) .
This is quite an audible vibrato.
But now do the same thing with,
say, 880 Hz, which is not the top of
the keyboard by any means. With a
one -second vibrato rate again, a
single phase -shift stage can shift
only from 879.2 Hz to 880.8 Hz,
which is ± 0.06%, a deviation only
the very best ears can barely detect.
You'd never know you had vibrato!
To use the phase -shift method,
multiple stages are needed, so that
total phase shift can run several
cycles or periods. If we rule that out
as too complicated for us to tackle,
we are left with methods that change
the tuning of the oscillator. Organ
makers do this in one of two ways.
Since semiconductors came into
vogue, a popular way is to change
the tuning of the oscillators by
changing the bias on a diode that,
when conducting, shunts an extra
capacitor across the tuned circuit
(Fig. 3-6). This is from a Lowrey
circuit. When we discuss this, we'll
find that care is needed in how the
bias is changed, to avoid a jerky vibrato.
The other method in common use
changes the bias of the oscillator itself. This is used in Fig. 3-5, which
is typical of the method used in tube type circuits. The actual mode of
operation varies. The Conn, shown
in Fig. 3-5, uses the oscillator almost
in Class C. An oscillator working
this hard, so the active element is
inactive for the major part of the
period, can best be considered as
tuned circuit again.
Changing bias, which the vibrato
voltage does, thus varies the amplitude more than frequency, although
they are never completely separate.
Although the vibrato connection
in Fig. 3-4 looks similar to that in
Fig. 3-5, it works a little differently.
The vibrato changes the bias in the
base circuit, but it works through the
change in collector voltage this
causes. It combines frequency and
amplitude shift.
Any vibrato circuit that shifts frequency can leave it permanently
shifted, or out of time, if switching
the vibrato off leaves an asymmetrical bias from the mid -point of the
vibrato fluctuation. So the vibrato
circuit must be designed to care for
this.
This installment has covered most
aspects of tuning (as regards stability, not the job of tuning the organ) .
Some modern organs use variable
resistance for tuning, but the majority use a variable inductance. In the
next installment, we'll move on to
different ways of putting the possible electronic pieces together to
make a whole organ.
HOW
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THE W4-101,E
TRUTH
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The reproduction of
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You'll like the sounds you hear from
a Klipschorn only if you like the
sounds that were recorded. It has
no sound of its own. If you're looking
for exaggerated bass, sensational
treble, or dramatic "hi-fi" effects,
don't depend on your sound repro-
ducing system, tell the recording
artists. Strictly speaking, there is no
such thing as "high fidelity!' only
"fidelity" or "infidelity:
Our speakers are designed and built
for but one purpose fidelity.
They're built in Hope, Arkansas,
under the personal supervision of
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you get a system with fidelity.
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NOVEMBER 1968
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BEHIND THE SCENES
stage which could pick up the real
sound of the dancing and moving
around, since the mikes naturally could
not pick up the voice and orchestral
tracks.
(Continued from page 12)
were great chambers, but they were
costing us too much in rental so we put
in EMT units. We found an interesting
thing with the EMT units quite by accident. We put them right in the ballroom and found that we got acoustic
coupling of the EMT's from the orchestra in the room, aside from the electrical drive, and it makes an unusual
sound. I have an idea that ultimately,
if we ever get time, I want to suspend
plates in the studio over the various
orchestral choirs ... probably they will
be much lighter in weight than the
plate in the EMT, but likely of hardened steel. With them we'll pick up
reverb selectively from the sound
waves of the orchestra impinging directly on the driving unit. It may be
impractical, but I'd like to try it.
How do you intend to use this technique?
FINE: Well, we have such a maze of
wires in the studio when we put out as
many as 40 earphones on one of these
8 -track pop recordings, that we are
thinking of installing a similar radio
transmitter earphone system. The only
thing to figure out is how to keep the
earphones from vanishing after each
session.
suppose you try to use some inexpensive
phones, but there is a limit as to how
much you can restrict quality.
I
FINE: Right, but even the little phones
such as supplied with transistor radios
cost 50 cents apiece. Nevertheless, we
are going ahead with the radio earphone system for the flexibility it will
afford.
How many inputs on your consoles? Does
it vary?
FINE: Studio A has 14 inputs, Studio
B has twelve. The new console for
Studio A will have 24 inputs with a 16 -
channel output, plus a semi -computerized matrix mixing system, where you
mix the monitor. In these multi -track
systems, where you record wide open
to the 8 or 12 tracks, where there is no
mixing, they matrix the monitor, listen
to every channel and mix in on the
monitor so they hear some semblance
of what they are doing, even though it
has nothing to do with what is going
on the tape. You also need an earphone mixing system, which we have
in Studio A, because you are selecting
from so many tracks a mixture of something to feed to the musicians to selsync against. Speaking of earphones,
we are thinking of adapting an old
Hollywood movie technique that is
quite interesting. I should note at this
point that all the 8- and 12- and 24 track recording of today is merely a
modern upgrading of what are essentially old movie techniques.
You mean they actually did multi -track
recording in those days?
FINE: I'll give you an example. In the
old musical pictures of the Astaire/
Rogers era, the orchestra recording was
made, then the singing recording
all on optical push-pull tracks, and on
synchronized equipment. This was
played back to the artist who was photographed lip-synching to the sound.
Loren Ryder of Paramount Pictures
made an ingenious invention in the late
thirties. He felt there was something
missing about those people dancing in
the musicals ... the real sound of their
clothing, the real sound of their danc-
..
.
Bob, in which of your studios do you
prefer to do a rock-and-roll recording?
FINE: We are presently building Studio
E, which among other things will have
an especially dead room for this type
of multi -track recording. However, as I
have pointed out, due to the use of
click tracks and sel -sync, even the ballroom is suitable.
Fig. 3-Cutting Engineer George Piros is
shown at the controls of a Scully lathe
used by Fine Recording.
4-35 mm magnetic film dubbing in
Studio "C."
ing in the room that makes it lifelike,
as compared to the lack of perspective
in the picture where the sound was always at the same level, whether the
dancers were close-up or far away. So
he put a 150-kilocycle radio transmitter with a huge loop over the shooting
stage and with a big antenna radiating
from the roof of the building .
reFig.
.
.
member, this was long before solid
state, a typical brute force system ..
and made a device that fitted behind
the performers' ears and couldn't be
seen, with a germanium rectifier and a
bone -conduction earphone ... and just
pumped enough "juice" into this system to rectify enough to drive the bone conduction unit. Then they could play
back the various orchestra and singing
tracks to the performers, who could
dance, while leaving mikes open on the
100
On these rock-and-roll dates, the musi
cians are equipped with electric guitars
and other electric instruments, each with
its own amplifiers and speakers. I assume
you don't pick up the sound of their
speakers via microphone, but go into your
preamps directly from their bridging outputs?
FINE: No, we don't go in direct. But
it is wise to eliminate mikes. I've found
that the only place you can get that
raw sound peculiar to these instruments is across the voice coil of their
speakers. You don't get the same thing
out of their bridging amp output because it is before the power stage. So
we are putting in a system that clips
right to the voice coil. This picks up all
the "distortion" that gives these instruments their "character" and would appear to be a product of the clipping
of the output transistors.
Disc cutting has always been one of your
major interests. What constitutes your
present system?
FINE: Our stereo disc mastering equipment is of our own design. You'll be in-
terested to know it was installed 9
years ago. We took a different philosophy about what is necessary to cut a
stereo disc than generally prevails in
the industry. For one thing, we use
AUDIO
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AmericanRadioHistory.Com
NOVEMBER 1968
softens to a "listen," the cartridge used is the ADC 10EMkII.
Top -rated, this mini cartridge
is almost human in its instinct.
200-watt -per -channel modified McIntosh's as our cutting amplifiers. And
we use only the original Westrex 3A
It brings out the brilliance,
cutter.
Why is that, Bob? I've heard comment
that "Fine ought to get modern and use
the Westrex 3D."
FINE: We modify the suspension of the
3A ourselves. We don't use feedback.
We use something else because we don't
believe in feedback, especially the Wes-
trex feedback system, because that is
not a true way to correct mechanical
motion.
That surprises me. -Weren't you always an
advocate of feedback in the days when
you used the Miller cutter?
not the same feedback ..
the Miller used a mechanical feedback.
There were certain rods in the cutter
that had to be tuned. At any rate, with
our present system we can put pulse
information and high frequencies on a
record without resorting to Conax
equipment. [the Conax equipment is a
frequency -selective limiting system]
Almost every studio in New York uses
Conax equipment because the Westrex
3D systems will not pass high -frequency, high -power information, so
they use frequency compression systems to get the level on their records.
FINE:
It
is
.
Six or seven months ago we got a Westrex 3D cutter and set it up on another
Scully lathe. We were asking ourselves
whether we were behind or ahead in
cutting technology and thought it was
time for a general review of disc cutting. We set up the 3D without a Conax
and fed it and our 3A system the same
program material. As far as I was
concerned, the 3D couldn't put what
I wanted on the disc. The 3D exhibited
that d.c. blocking which comes from
feeding instability in the system ... it
just sounded nothing like we were
doing. You couldn't put anywhere near
the peak levels on the record that we
could with our system.
Some people will never be "in."
Their fancies run high and they
are fanatically loyal to logic,
imported beer and aged cheese.
Their taste in music can run
the gamut of Beatle fad, Bach
fugue and Ravi Shankar.
The one thing that is most
common is a demand for great
performance.
When the conversation becomes subdued and the mood
from the lowest bass to the
highest treble.
HiFi Stereo Review in an
independent survey made these
claims, "... its ability to trace
highly modulated grooves at
only 1 gram, is a feat achieved
by few cartridges in our experience." And, "... it would track
the HF/SR test record at 0.5
gram, lower than any other
cartridge tested."
And, England's Hi-Fi News
had this to say: "It can be
stated unequivocally that this
The"Out- Crowd Plea ser:'
is a beautiful pickup which
must be ranked among the best
available."
The cost is high. Just a breath
under sixty dollars. But understandably so. Our appeal is to a
small "out" crowd. For com-
plete information write
ADC or hear
it at your
Z
ADC dealer. ADC 10E-MKII
AUDIO DYNAMICS CORPORATION
New Milford, Conn. 06776
Check No. 129 on Reader Service Card
They still don't know how
we did it
Getting the big sound of a 12 -inch woofer and a midrange tweeter
from an enclosure measuring only 71/4 x 101/2 x 51/2 inches was
thought to be impossible.
The famous Maximus 1 changed all that. Today, our ultra -compact
Maximus has imitators, but the creative and advanced engineering
that made it possible is still there in every speaker system of the
Maximus line.
Budget systems, compact units, or magnificent 4 -speaker 3 -way
systems. Seven superb speaker systems, from $39.95 up. Find
the one for you. See your Maximus dealer.
MAXIMUS
was under the impression that most companies using the 3D are using the HAECO
I
amplifiers, which are reported to be quite
good.
FINE: Yes they are, and the HAEco is
quite an improvement over the Westrex amplifier, which is really rather
primitive. But this still does not overcome the problems of the 3D. The 3D,
by the way, was made with a looser
suspension to reduce the power requirements. I don't believe in that. I feel
that a cutter should be absolutely
rigid. The Miller cutter had no movement of the armature at all
you
actually distorted the metal with a
magnetic current.
.
.
.
UTC SOUND DIVISION of TRW Inc. 809 Stewart Ave.. Garden City, N.Y. 11530
Check No. 130 on Reader Service Card
AUDIO
101
NOVEMBER 1968
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AmericanRadioHistory.Com
TEN YEARS
THE
I notice you still use the Scully lathes. Do
you anticipate any changes, perhaps to
the new Neumann computer lathe, for
example?
WORLD'S LEADER
FINE: I think they are fine machines
and are good for studios with a great
amount of disc cutting, but they are
1958
1959
1960
1961
1962
1963
1964
1
96 5
1
96 6
1
9 6 7
1
968
III
NAGRA
SYNCHRONOUS
fä" TAPE RECORDER
NAGRA MAGNETIC
RECORDERS, INC.
565 Fifth Ave., New York, N.Y. 10017
Western States Service
RYDER MAGNETIC SALES CORP.
1147 N.Vine St.,
SEE NAGRA
Hollywood, Calif. 90038
-
BOOTH
=17
AUDIO ENGINEERING SOCIETY EXHIBIT
OCTOBER 21-24, 1968
PARK SHERATON HOTEL
NEW YORK
concessions to individual mastering. In
other words we took off all the Scully
sensing equipment on our automatic
variable pitch lathes. This would have
made life easier having it, but it can't
"think" how much the time factor is on
the record or how loud you want the
record to be. So you are making a concession whether you master with a
Scully or Neumann or Ortofon automatic system. You never really make a
record on this kind of equipment that
has that little extra something in it that
makes it a better product. I believe that
when you go to the trouble and expense
of making a symphony recording or any
high -quality recording, it deserves to
be cut onto a disc with individual attention to levels and dynamics and
every other significant parameter. However, just so I won't be accused of sour
grapes
if I had the amount of disc
cutting that RCA and Columbia do,
I would own an automatic Neumann
...
too!
Bob Fine has often been accused of putting too much level on records.
FINE: It's true
I feel that the records should have a lot of level on them.
I must confess we do get up to extreme
velocities.
...
Up to 30 centimeters per second,
stand.
I
under-
FINE: Yes, peaks of 30 cm, but in defense I challenge you tQ see a Teldec,
a Grampian or a Westrex 3D cutter put
that down on a record, and put it down
with complex pulse.
Can present playback equipment cope
with these high velocities?
FINE: Most certainly the better stereo-
phonic arms and cartridges can, and
even some lesser consumer equipment,
which is getting better all the time.
addition to all your studios you have
a tape -duplication facility in the basement
of the hotel. Is it the usual master playIn
back with reel-to-reel slave machines, or
do you use a common mandrel system?
FINE: We have a master and ten slaves
in a special modification which is saving us a lot of money. Heretofore, if we
were not running the kind of tape for-
mat the slaves were set up for, the machines were idle and non-productive.
Now these ten slaves have a programmed head system. They have a 52 prong machined base, with a 52 -prong
plug-in head assembly which is
changed for each tape configuration.
On quarter -inch tape we have interchangeable heads for monophonic, two track, and four -track. On cassette 150 mil tape, we have two- or four-track
heads. The heads pick up the guidance
of the type of tape and there is room
to program the tensions on the machines and what kind of a master is
being used
either loop or reel to
reel. On the top of each head is a level
and bias control
no more diddling
with the bias controls on rear panels.
So whatever kind of tape format we
are asked to duplicate, it is a simple
matter of plugging in the appropriate
head, and this keeps the "down -time"
on the machines to a minimum. We do
cassette duping at 16 times speed ratio,
reel to reel at 8 times speed, and 8 -track
cartridge is also duped at 8 times the
speed ratio. The 8 -track is made on
another bank of ten slaves which we
are going to convert to the plug-in programmed head system.
.
.
.
...
High hiss levels seem to be the particular
curse of present cassettes. Can't anything
be done to bring the hiss down to "tolerable" level?
There is a very critical bias -frequency and bias -level problem when
running cassette dupes at 16 times the
speed. There are also problems of stability with the tape and tape tensions
on the duplicators. We are making
progress in overcoming these problems.
We are now looking into different
types of bias systems. We are looking
into different bias arrangements than
just the bulk pumping of bias into a
head to record. There has been a lot
of saturated gap recording. I have no
experience with it, but question the
merits of this approach. I believe there
will be technological advances that will
eliminate the basic practical problems
of bias on tape. Most present oxides are
a holdback. In our duplication set-up
we have tried many different kinds of
tape, and only one tape works well
at high speeds.
FINE:
What are your feelings about the new
DuPont chromium dioxide tape?
FINE: I think there is great potential
in the Crolyn tape.
What about the reported abrasiveness of
the tape to the head and the requirement
for almost double the bias?
FINE: The bias problem exists because
of the present configuration of the circuitry. We certainly can build new
equipment to handle this, and I believe the abrasiveness can be licked.
Do you think tape and disc can continue
Check No. 102 on Reader Service Card
102
AUDIO
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AmericanRadioHistory.Com
NOVEMBER 1968
to co -exist in the music market?
FINE: Very definitely. I think
both
mediums have yet untapped potential.
I am very optimistic about tape as a
recording medium. With its constant
lineal speed there is no diameter problem, as in the case of discs. Since most
music has a loud finale, and this usually appears at the inner diameter of
a record, we run into tracking difficulties. This has no relevance in tapes. Of
course, one of the big problems in tape
duplication is the number of generations we must go through before we
get to the consumer product. What we
get from a record company is usually
a third generation working part. This
is, in essence, library material which
we can't cut up, so from that we make
an intermaster, which is then compressed in dynamic range to give us a
better signal-to-noise ratio with all the
dubbing going on. Then the tape goes
through program preparation, according to whether it is cassette, 8-track,
etc., and a running master is made.
This is your dubbing master for highspeed duplication. The result of all this
is that we may have gone through six
or seven generations. Which, incidentally, is what makes the Dolby system
so useful in this respect. Naturally all
this dubbing of tape cannot be compared with a record, which, at worst,
is a third -generation product. Consequently, a good record is quieter than
most pre-recorded tapes, and why the
record still is so strongly competitive.
Telex Encore
Stereophones
Made in America
Unbelievable at
$9.95
(Clever, these Americans)
You'll become a believer once
you look and listen. Dramatic
sound. 50 to 18,000 Hz. response.
Light weight. Comfortable. Tough
Cycolac plastic. Removable foam
filled vinyl cushions. Rugged 8'
Superflex cord. Hearing is believing. See your Telex dealer.
TELEX.
9600 Aldrich Avenue South
Minneapolis, Minnesota 55420
Check No. 131 on Reader Service Card
The cassette seems to have caught the
fancy of the public. Would you venture
some prognostications about the future
of cassettes?
FINE: For one thing, I have no doubt
that chromium dioxide tape is a superior medium for cassettes. I foresee
that a whole LP record can be contained in a package half the size of the
present cassette, running at a speed of
a half -an -inch per second, that will give
you a frequency response from 15 Hz
to 20 kHz. There should be no problem with heads. The cassette will be
"bubble" packaged, which should cost
less than a cent and a half, and the
total cost will be less than a record
pressing. I envision this within 5 years.
What about signal-to-noise ratios?
FINE: It will be far superior to what
we have now. You see, head technology
is moving ahead at a tremendous pace.
This is due to the stimulus of sophisti-
cated telemetry systems in the space
program, where they are doing incredible things with frequency response at
slow lineal speeds. I am certain many
of these advances will "filter" down to
Æ
the consumer level.
It's Crown's model SHC55 high
fidelity stereo instrument with
AM/FM/FM stereo tuner, stereo
phonograph, 30 watt stereo amplifier
and professional type stereo tape
cassette deck. Compact stereo components-a complete tape home
entertainment system, engineered
and manufactured by Crown, the
tape recorder professionals. Super
compact and super attractive in a
rich handsome walnut table -top cabinet. You select the speaker system
that YOU want. Our CPS7's are
optional.
Only $349.95.
Ask about our new Model SHC51/
FM500*, too. This 3C watt, combination stereo cassette recorder and
AM/FM/FM stereo tuner is an industry first! Only $299.95 including
handsome walnut case.
' Not illustrated.
WAN
See your local Crown Dealer or write INDUSTRIAL SUPPLIERS COMPANY
755 Folsom Street, San Francisco, California 94107
Check No. 132 on Reader Service Card
AUDIO
103
NOVEMBER 1968
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AmericanRadioHistory.Com
WORLD'S
FINEST
CLASSIFIED
Rates: 25¢ per word per insertion for noncommercial advertisements; 50¢ per
word for commercial advertisements. Frequency discounts as follows: 2 times,
less 15°/o; 6 times, less 20°/o; 12 time s, less 30°/o. Closing date is the FIRST of
the second month preceding the date of issue.
ERSIN
SERVICES
FOR SALE
HIGH FIDELITY SPEAKERS REPAIRED
SCULLY Professional Tape Recorders, from
AMPRITE SPEAKER SERVICE
168 W. 23rd St., New York, N. Y. 10011
CH 3-4812
to 12 tracks, complete recording studios
available in prewired console cabinets
starting at $8,000.00. 70°/o financing. WIEGAND AUDIO LABORATORIES, 3402
Windsor Rd., Wall, N. J. 07719.
PROTECT YOUR LPS-Heavy poly sleeves
for jackets 5¢, Round bottom for records
3'/2¢ ea. New LP jackets, White 20¢, Colors
25ç. Min. order $5.00. House of Records,
Box 323A, Hillburn, N. Y. 10931.
MULTILORE
RENT STEREO TAPES-75¢ week. Catalog.
Art's 1613'/2 N. Mariposa Ave., Hollywood, Calif. 90027.
CUSTOM RECORDING SERVICE. Tape and
disc. Stereo and mono. Live and copies.
Editing. Masters and pressings. High quality at reasonable rates. Joseph Giovanelli,
Audio -Tech Laboratories, 2819 Newkirk
Ave., Brooklyn, N. Y. IN 9-7134.
BUY IT AT RADIO-TV PARTS STORES
Check No. 133 on Reader Service Card
1
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ALLIED RADIO, Dept. 134
P.O. Box 4398, Chicago, Ill.
60680
Print
Middle
Last
ADDRESS
CITY
STATE
HARPSICHORD: Same as owned by Philadelphia Orchestra and RCA Victor. In kit
form for home workshop assembly, $150.
Clavichord kit, $100. Free brochure. Write:
Zuckermann Harpsichords, Dept. R. 115
Christopher St., New York, N. Y. 10014.
DISC RECORDING EQUIPMENT: Cutter heads, Recording Amplifiers, and Lathes.
New and used. From Rek-O-Kut to Scully.
Send requirements. Wiegand Audio Labs,
3402 Windsor Rd., Wall, N. J. 07719.
for money saving stereo catalog AM and lowest quotations on your individual component, tape recorder, or system requirements. Electronic Values, Inc.,
200 West 20th St., New York, N. Y. 10011.
FREE! Send
RECORDING MAGAZINE-Enthusimonthly magazine for amateurs and
professionals. Send $3.75 for 1 year subscription to 14-18 Holborn, London, E. C.1.
TAPE
asts
ZIP
EQUALIZER, passive for tapes, records and
mikes. Full frequency. Detailed specs and
graphs. Megatronics, 214-05 Richland Ave.,
Flushing, N. Y. 11364.
ACOUSTIC RESEARCH, Dyna, Koss, Shure
discount specialists. Write for free catalog.
SCS Corp., 95 Vassar St., Cambridge, Mass.
02139.
2 ALTEC
M50 Condenser microphone sys-
tems. Each system contains: Cardioid capsule, preamp, battery power supply, windscreen, 25 ft. cable. 6 months old. Excellent
condition. $300. Charles P. Repka, 76 Tuella
Ave., E. Paterson, N. J., 07407. 201-7963783.
JAPAN PRODUCTS SERVICE. U.S. $5 per
inquiry or U.S. $30 yearly. Intercontinental,
CPO 1717, Tokyo, Japan.
STEREO TAPES saves up to 30°/o; no mem-
bership fees; postpaid anywhere in USA.
BIG 70-page catalog 50(ph). We discount
batteries, recorders, tape/accessories. We
will not be undersold. For information
send to: William & Diffay, 19 W. 020 13th
St., Lombard, Ill. 60148.
CATALOGS Broadcasts, Soundtracks, Personalities of Thirties, Forties. Box 225, New
York, N. Y. 10028.
RECORD RIOT! Five 45 RPM's, $1.00. Albums, $1.50. SPECIAL, 3 albums PLUS 5
singles for $5.00. By famous rock groups.
Satisfaction guaranteed or money tearfully
refunded! J.A.S., P.O. Box 403, Queens,
N. Y. 11379.
England.
NEW HIGH -QUALITY SPEAKER SYSTEMS,
TAPE RECORDER
Please
NAME
First
FOR SALE
1
Brand new nationally advertised brands, $10 above cost.
Amazing discounts on stereo components.
Arkay Electronics, 1028-H Commonwealth
Avenue, Boston, Mass. 02215.
SALE.
SCOTCH
RECORDING TAPE,
lowest
prices. Tape Center, Box 4305, Washington, D. C. 20012.
cabinets, OEM. Write for information. Cizek Enterprises, Inc., P. O. Box 1342,
Bloomington, Indiana 47401.
TWO ELECTRO -VOICE
Bass Horns with
15WK's. Factory made. Magnecord PT6AH/J Recorder. Wanted: Hartsfield Speaker System. Paul Lambidakis, 7213 Cedar
Ave., Takoma Park, Maryland 20012.
Check No. 134 on Reader Service Card
104
AUDIO
www.americanradiohistory.com
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NOVEMBER 1968
FOR SALE
STEREO COMPONENTS, Tape Recorders,
Tapes, Citizen -Band Transceivers, Brand
Names, Free Catalog, Free Quotations.
GLOBE ELECTRONICS SALES, INC., 1160
Globe Avenue, Mountainside, New Jersey
07092.
ELECTRO-VOICE ARISTOCRAT, Mahogany, SP12B, T358B; perfect cond. $75.00
plus freight. R. Markese, 171 W. Walnut
St., Des Plaines, III. 60016.
SONY CR -6 Wireless Microphone system.
Transistor receiver and transmitter. Batteries or AC operation. Condenser microphone. Mint condition. New $450. Sell
for $350. Charles A. Richardson, 1932 Old
Annapolis Blvd., Annapolis, Md. 21401.
100 4 -TRACK stereo tapes and LPs, $1 ea.
Dynaco Amp, tuner wired. J. Harry Feldman, 3345 Richmond St., Philadelphia, Pa.
19134.
FOR SALE: Ampex MX -10 Mixer,
3
mo.
old, $225; Shure M68 Mixer, like new, $45;
Bogen MX6 Mixer, $20; Ampex 601 Recorder, full track, $200; Ampex 620 Amplifier, $95. Vernon Castle, 642 Birches
Drive, Lake Geneva, Wis. 53147.
SOLID-STATE 50 -WATT rms plug-in d.c.
thru 25 kc operational power amplifier kit,
model 440K. Price $30.00 Plus $1.00 postage. Send for free catalog and 50 opera-
tional amplifier applications to: Opamp
Labs., 172 So. Alta Vista Blvd., Los Angeles,
Calif. 90036.
VARNER'S PIANO SHOP. In business over
25 years.
Impeccable reputation and
knowledgable audio service. Special: two
AR 2ax speakers, one ARXA turntable, one
AR Model A amplifier, one Shure V15
Type II cartridge, and Sherwood Model
S-2300 FET AM/FM tuner -$620, not including freight. Varner's Piano Shop, Box
176, Delaware, Okla. 74027.
MASTERING
AND REFERENCE COPY:
Mono, Stereo, Top notch equipment, top
engineering. Son -Deane Records, Hartsdale, New York 10530. Telephone: 914
OW 3-1590.
HYPNOTIZE SUCCESSFULLY! "Instantaneous" -"One Word" -"Against
Will"
Methods Exposed! Complete illustrated
course including "Secret Nerve Pressure
Technique" -Self -Hypnosis -10 inch Hypnodisk $2.00. RESULTS ABSOLUTELY
GUARANTEED! Fowler, Box 4398, Woodbury, New Jersey 08096.
MAGNECORD S36B, New electronics, 4 Track Heads. Plays, needs work to record
properly. $100. Alan Douglas, Box 225,
Pocasset, Mass. 02559.
AUDIO
FOR SALE
EQUIPMENT WANTED
genuine "Panamuse" Mahogany console Victrola of 1933 vintage
with 4 -band receiver and new record
changer. This audio collector's item originally cost $300. Make offer. Box 1276, Arcadia, Calif. 91007, Phone (213) 446-7445.
AMPEX 300 needed in either 4- or 8 -channel configuration, preferably with "Sel,
Sync." John DiCanio, 730 North Chestnut,
Arlington Heights, Illinois 60004.
CAPEHART,
DYNACO STEREO 70, wired, in sealed
box, $90.00. Rod Bauer, 5203 Tramore Rd.,
Baltimore, Md. 21214.
General Electric Rechargable Batteries. Size AA, C, D. $3.95 Pair; Charger
$9.95; Postpaid. Donald Bisbee, 685 South
Roys Avenue, Columbus, Ohio 43204.
AR1-W, Janzen 65 Tweeter, Shure SME
3009 Arm, Sony or Marantz Elec. Crossover, Parts for Weathers Turntable. Robert
Bartok, 561 Mill Street, Lincoln Pk., Michigan 48146.
SELL:
TWO McINTOSH MC -30 Amps with C-8
preamps. $100 each. Amp/Preamp combination or $180 all four pieces. Chrome
pitted. G. B. Zwetzig, 21107 Chase St.,
Canoga Park, Calif. 91304.
TWO AR 3's: Oiled walnut, used, new
sound. Best offer over $125 each. Stani,
170 Milford Street, Rochester, N. Y.
RECORDS, TAPES, Movies, Books. Send
250 for catalogs. Murphy's Records, Route
1, Box 600A, LaPlace, Louisiana 70068.
outstanding value pages sent free, brand
names, lowest prices, blank Cassettes, accessories. CASSETTES, UNLIMITED, P. O.
BOX 13119-A, Pittsburgh, Pa. 15243.
CASSETTE Tape Recorders, Players, 10
PAIR JBL OLYMPUS S8R speakers, Oiled
Walnut, perfect, $595 each. No. 15 Marantz, $325; No. 7T Marantz, Walnut Case,
$245; MX10 Ampex Mixer, $250; No. 2010
Ampex amp/spkr, $125; No. 1028 Magne cord '/2-tr, 15-7'/2, extra 1/4-tr playback
head and mike transformers installed.
$765. Frank Temple, Box 788, Winter Park,
Fla. 32789.
SERVICE TO THE TRADE
CIRCUIT BOARDS, name plates, power
transformers made to your specifications,
custom electronic equipment built from
your plans. Information 25¢. BELO (Ball
Electronics Co.) 1006 W. Riverside Dr.,
Salem, Va. 24153.
STEVENSON SONGWRITING: We will
write songs for you. We write words to
pre-recorded music, tape is preferred at
7'/2 IPS, 50e per song. Also Mike Mixer
for sale $15.00, excel. Michael Stevenson,
1199 Clairmount, Detroit, Mich. 48202.
SURVEILLANCE Countermeasures
Brochure $1.00. Neg-Eye, Box 1036, Anderson,
Indiana 46015.
STEREO Tape Club: Average cost $3.78$4.20. Cartridges, Cassettes, Reels. No
Minimum monthly purchases. Free bro-
chure-catalog. Star Recording, Box 1055,
El
Paso, Texas 79946.
Newest from
Electrodyne
INTEGRATED CIRCUIT
AUDIO
HELP WANTED
EXPERIENCED HI-FI, HAM, CB salesmen
wanted. J. S. Draper, Lafayette Radio Electronics, All Cape Shoppers Bazaar, Rt. 132,
Hyannis, Mass. 02601.
EQUALIZER
AMPLIFIER
MODULE
FRANCHISED DEALER for the following:
Klipschorn, Tannoy, Altec, Rectilinear, AR,
Inc., Wharfedale, Dynaco, Sherwood, Ken wood, Teac, Uher, Garrard, Benjamin.
Microphone preamplifier.
Low noise level
(-127 DBM equivalent input)
Superior Sound, 1801 Brewerton Rd., Rt.
11, Mattydale (Syracuse), N. Y.
Booster and echo amplifier
Four high frequency, two low
frequency equalization points.
EQUIPMENT WANTED
Isolated echo output
71DB gain overall
Simplifies console design.
WANTED -Heath Legato Speaker System,
Model H.H.-1. Write to Kenneth Wene,
402 E. 15th Ave., Columbus, Ohio or call
614-291-5277.
WANTED: ELECTRO -VOICE 15WK woofer
of pre -ceramic magnet design. Larry Clare,
1031C Preston, Charlottesville, Va. 22903.
NOVEMBER 1968
Designer color panels for
coding and color co-ordination
For complete literature write or phone:
rELECTRODYNE
CORPORATION
7315 Greenbush Avenue
North Hollywood
Phone
Cable Address
(213) 875
1900
Calif 91605
ELECIRODYNE.
Check No. 105 on Reader Service Card
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FOR YOU
with
a
FINCO
AWARD -WINNING FM Antenna
Model
FM
Benjamin Electronic Sound Corp. ..37, 85
93
Bose Corp., The
3
British Industries Corp.
-4
$24.90 List
II
World's Most Complete
line of HI-FI Phased
FM ANTENNAS
Write for Catalog 20-213.
FINNEY COMPANY
THE
34 WEST INTERSTATE
BEDFORD, OHIO
DEPT. AM
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_r.i
'We
e
UVe OWn
Pencif3
S,arpe3i
OU SAVE MORE
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45
103
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Crown Radio Company
COMPONENTS
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We invite your test of our
"We Will Not Be Undersold Policy."
15 -day money -back guarantee.
2-yr. unconditional guarantee parts &
labor no charge, at local warranty
station or factory.
Trade-ins-highest allow. Send your list.
Most items shipped promptly from our
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Our specialty-APO & Export.
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HI -FI DELI TY
CENTER
"The House of Low Low Prices"
239- V test 149th St.
New York, N.Y. 10451
Panasonic
Dolby Laboratories
52
Dynaco, Inc.
53
EICO Electronic Instrument Co.
Electrodyne Corporation
Electro -Voice, Inc.
Elpa Marketing Industries
Empire Scientific Corp.
5
105
Cover IV, 1
27, 87
75
lob
Finney Company, The
Fisher Radio Corp.
;
I
Garrard Sales Co.
Gauss Electrophysics, Inc.
Harman-Kardon
Heath Company
Hi -Fidelity Center
59
67
19
23
Pickering & Co. Inc.
Pioneer Electronic U.S.A. Corp.
ReVox Corporation
Cover III, 55
Sansui Electronics Corp.
Scott, H. H., Inc.
Sherwood Electronics Labs, Inc.
Shure Brothers, Inc.
Sony Corporation of America
69
Cover
II
20
9, 61
63
Sony/Superscope
Stanton Magnetics
Sterling Hi-Fi
Superex Electronics Corp.
6, 15
31
95
98
TEAC Corporation of America
Telex Corporation
Qn
n
JoWn
ON
33
Acoustic Research, Inc.
AKG Div., North American Philips Co. 39
104
Allied Radio Corp.
89
Altec Lansing
35
Ampex Corporation
101
Audio Dynamics Corp.
51
83, 103
University Sound
UTC Sound Division, TRW, Inc.
11, 77
101
Viking
83
cassetie
becomes
bl-lì
47, 48, 49
106
Jensen Manufacturing Division
JVC America, Inc.
I
7
settle for low -fi when you
upgrade your K -Set tape
player with a Michigan Magnetics
Don't
Kenwood Electronics
Klipsch & Associates
Koss Electronics
71
99
79
17, 65
Marantz Company
Martel Electronic Corp.
91
43
Martin Audio Corp.
Matsushita Electric Corp. of America
67
McIntosh Laboratory, Inc.
16
106
Michigan Magnetics
can
head. These heads are completely
compatible with Norelco, Mercury, Standard, and most import
K -Set
machines.
The
complete
family of heads is made in the
U.S. and immediately
available
from Allied Radio
Multicore Sales Co.
104
MICHIGAN MAGNETICS
Nagra Magnetic Recorders, Inc.
102
VERMONTVILLE, MICHIGAN 49096
A DIVISION OF VSI CORPORATION
Nivico
7
North American Philips Co., AKG Div. 39
Nortronics Corp.
97
Telephone (517) 259-8911
Send For:
Consumer Audio Catalog # 680
Check No. 128 on Reader Service Card
Check No. 106 on Reader Service Cord
106
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
NOVEMBER 1968

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