User manual | May - American Radio History

Tomorrow's electronics
for today's enjoyment
new Scott 342C 100 -watt
FM stereo receiver
NEW 100-WATT SCOTT 342C..THE WORLD'S
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Power: IHF ±1 dB @ 4 Ohms, 100 Watts; IHF ±1 dB @ 8
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IHF Sensitivity, 1.9 µV; Frequency response ±1 dB, 20-20,000
Hz; Cross modulation rejection, 80 dB; Selectivity, 40 dB; Capture ratio, 2.5 dB. Prices and specifications subject to change
without notice. Walnut -finish case optional.
OS CO TT®
Dept. 35-05 Maynard, Mass. 01754
Export: Scott International, Maynard, Mass. 01754
Check No. 100 on Reader Service Cord
AUDIO
ARTHUR P. SALSBERG,
Editor
C. G. MCPRouD,
EDWARD TATNALL CANBY,
May 1969 Vol. 53, No.
Successor
Publisher
Associate Editor
JOHN HUBBARD
RICHARD CLIFF
Art Director
Design
L. CAHN
BAXTER
Production Manager
Advertising Manager
SHERWOOD L. WEINGARTEN
MARY CLAFFEY
Subscription Manager
FEATURE ARTICLES
Behind the ScenesThe $$ Crunch in Classical Recording
A "Pop" Recording Session
Crossover Distortion in Transistor Power Amplifiers
ABZ's of FM
West Coast AES Convention Papers
AES Exhibit Preview
Electronic Organs-Part 9, Conclusion
10 Bert Whyte
21 John M. Woram
26 James Bongiorno
30 Leonard Feldman
32
36
54 Norman H. Crowhurst
EQUIPMENT PROFILES
Sony/Superscope Portable Tape Deck 40 TC-770-2
H. H. Scott Stereo FM/AM Receiver Kit 42 LR -88
Rabco Servo-Driven Straight -Line Tone Arm 48 SL -8
Fairfax Bookshelf Speaker System 50 FX-100
RECORD/TAPE REVIEWS
Classical 14 Edward Tatnall Canby
Jazz 58 Bertram Stanleigh
Light Listening 60 Sherwood L. Weingarten
Tape Reviews 62 Bert Whyte
AUDIO IN GENERAL
Audioclinic
Book Review
What's New in Audio
2 Joseph Giouanelli
4
6
8
Letters
Tape Guide 16 Herman Burstein
Editor's Review 18
Classified 64
Advertising Index 66
fTITLTL Or
MANUFACTURERS
NC
BEN COCHRAN
Chief Engineer,
Military Products
JUDITH S. ZucKER
BERT WHYTE
HIGH FIDELITY
a series of discussions
by Electro -Voice engineers
Number 68 in
Est. 1911
T. THALBERG
Publishing Director
R. KENNETH
ALEXANDER ROSNER
LEONARD FELDMAN
5
Marketing Director
JOSEPH GIOVANELLI
BERTRAM STANLEIGH
,
GERSHAN
SANFORD
Contributing Editors
HERMAN BURSTEIN
to
ADI
To most people, all handsets are about alike.
But to the U.S. Army Electronics Command
at Fort Monmouth, handsets are a vital link
in field radio communications. And the
handset that works fine on your telephone
may have serious limitations in battle.
To this end, Electro-Voice has developed a
dynamic handset with characteristics that
help to solve the problems posed by'battlefield conditions. Goals set for the design included reduced mass (both size and weight),
increased reliability and durability, and
equal or better acoustic and electrical performance.
Perhaps the most dramatic change was in
mass. Part of the achievement can be credited to more sophisticated use of plastics.
Wall thicknesses were reduced and held to
very close tolerances. Dynamic microphone
and receiver elements were molded directly
into the outer shell, eliminating redundant
enclosures. The net result was a reduction
of mass of over 50% compared to the original design, without loss of durability. Indeed the lower mass reduces the likelihood
of damage if the handset is dropped.
Simplicity was also the watchword in the
new design. One result was a new switch
that eliminates springs as part of the detent
action. Instead a magnetic detent is used,
with vastly greater reliability. Life tests indicate over 2 million on -off cycles without
failure, compared to about t -million for
conventional switch designs.
Conventional form factors were abandoned
in order to tailor the handset shape to the
specific needs of the user. The slim earpiece
fits more easily under a helmet, for example. Improvements in performance also were
achieved. Increases in earphone output level
and microphone efficiency were attained,
largely the result of superior steels and magnetic circuit design. And the mass and
complication of a matching earphone transformer was eliminated by successfully winding voice coils to match the 1000 ohm
standard.
The net result was an unusual -looking but
remarkably effective handset that has proved
far better suited to battlefield use than the
conventional designs. Work is now going
forward on noise -cancelling versions that
will take full advantage of the one-piece design to offer a significantly higher order of
cancellation than earlier models.
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, $5.00 for one year; $9.00
for two years; all other countries, $8.00 per year. Printed in U.S.A. at
Philadelphia, Pa. All rights reserved. Entire contents copyrighted 1969 by
North American Publishing Co. Second dass postage paid at Phila., Pa.
For reprints of other discussions In this series,
or technical data on E -V products, write:
ELECTRO -VOICE, INC., Dept. 593A
602 Cecil St., Buchanan, Michigan 49107
REGIONAL SALES OFFICES: Gershan T. Thalberg and Sanford L. Cahn, 41
East 42nd St., New York, N. Y. 10017; Telephone (212) 687-8924.
Louis Weber, 5201 N. Harlem Ave., Chicago, Ill. 60656; (312) 775-0755.
Jay Martin, 15010 Ventura Blvd., Sherman Oaks, Calif.; (213) 981-7852.
ge.ep
AUDIO Editorial and Publishing Offices, 134 N. 13th St., Philadelphia, Pa. 19107
Postmaster: Send Form 3579 to the above address.
A
ofez
SUBSIDIARY OF GULTON INDUSTRIES. INC.
Check No. 101 on Reader Service Card
1
Coming in
June 1969
Can Crossover Distortion Be
Detected By Ear?-James Bon -
giorno compares modified
of transistorized
power amplifiers and a tubed
power amplifier in a listening test to learn if crossover
distortion reveals itself to the
versions
ear.
Post Recording Session Tech-
- John
Woram discusses the re -mix or tape
mastering methods used after
a recording session is completed.
... and more.
niques
EQUIPMENT PROFILES:
EICO Model 3150 stereo in-
tegrated amplifier and Model
3200 stereo FM tuner, Thor ens Model TD -125 "Electronic" manual turntable, and
others.
ALSO: Record and Pré -Recorded Tape Reviews, ABZs
of FM, Sound & Decor Styles,
and other regular departments.
ABOUT THE COVER: The brass
section of an orchestra is shown
during a recording session. Trumpets, not shown, are behind the
sound baffles, between the french
horns and the trombones. In the
spot photo, a Shure 546 dynamic
microphone is used in close for
an "up tight" pickup of the guitar.
2
Andioclinic
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.
Ping-Pong Stereo
Q. A friend of mine has a stereophonic set. The sound jumps from one
speaker to the other. In my stereo
music system, the sound does not.
What's wrong?-R. Roy Downsview,
Ontario, Canada
A. Some recordings are designed
specifically to bring about this stereo
effect. Classical music discs are not so
designed, and not all "pop" records are
so made. Therefore, it may simply be
that the records you are using are not
dramatic, and hence you do not obtain
the obvious type of stereo, known sometimes as "ping-pong stereo." If your
friend was playing a record, borrow it
from him and play it on your equipment. You should obtain the same effect that he did unless something is
wrong with your system. We will discuss that possibility now.
If two speakers are placed very close
together, you will not obtain much in
the way of stereo information. Both
speakers will produce sound, but their
proximity to one another will mean
that the sound from both speakers is
being radiated from virtually the same
point source. Therefore you cannot obtain a stereo effect. For the average
listening room, a separation of the
speakers of between six and eight feet
would seem ideal. If you still do not
obtain stereo, we must look to something else.
First, are both speakers working? If
they are, and you are not getting stereo,
the sound should be coming from a
point midway between the two speakers. If it appears to be coming from
two separate locations, reverse one set
of speaker leads, leaving the other
speaker wires as before. This should
enable you to hear all mono sounds
from the center, between the two speakers. Making this simple change can
result in marked improvement of the
stereo effect.
Do you get stereo from your tuner
and not from the phonograph? It might
be that you have your cartridge wired
incorrectly. Check the wiring against
that shown in the instructions which
came with the cartridge.
Check to see that the amplifier connections to the speakers are correct.
Perhaps one channel is shorted out.
Perhaps you have accidentally wired
two channels in parallel.
Check to see that all your controls
are set to receive stereo, whether from
FM or from phonograph.
If none of this works, you will need
to trace through the amplifier stage by
stage to find where the stereo separation is lost.
One Too Many Leads?
Q. My problem is that I have a dynamic microphone which has two leads,
one white and one red, inside the
shield. My tape deck, however, will accept only the conventional phono plug
with one lead and shield.
Is there any way I can adapt this
microphone so that it will be useful in
this situation?-J .C., El Paso, Texas
A. All else being equal, you will have
no trouble using your microphone with
your tape deck. Connect the white lead
and the shield together, and connect
this combination to the ground side of
the phone plug. The red lead goes to
the "hot" side of the plug.
I said "all else being equal" for a
reason. If the mike is low impedance
and your tape recorder is high impedance, you will not get much output
from the mike. If the mike is high impedance and the tape recorder is low
impedance, you might or might not
have sufficient output. There is a possibility that your mike will lack bass
to some degree. Especially in the first
instance, you can cure the problem by
using a mike transformer to match impedances between the mike and the recorder. That scheme might also be tried
in the second instance, but the transformer would have to work backwards.
The winding which is normally the
primary would serve as the secondary,
and vice versa.
A.C. Line Transients
Q. Twice recently I have had extensive power-supply damage in completely separate pieces of equipment. I
feel certain this damage stems from
the a.c. power line.
I observe "spikes of over 400 volts
Check No. 3 on Reader Service Cord
-
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exceptional arm: Fully adjustable counterweight is r dynamic balancing Rigid, one-piece aluminum construction
insert of Afrormcsla--least remnant of woods the gyroscopically gimballed mounting in which the arm floats,
on needle pivots, virtually friction-free Tiny ball bearings for freedom of movement Calibrated stylus pressure
gauge Tonearm safety rest Slide -in cartridge dip that assures positive alignment. Not showt.: The patente 1,
permanently accurate sliding weight anti -skating control Safe, gentle cueipause control The incomparable
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displayed on an oscilloscope. These
transients are of very short duration
and do not show up on a conventional
recording voltmeter designed only to
show average voltage fluctuations.
However, they do last long enough to
destroy transistors completely.
Can you suggest a protective circuit
using Zeners or other devices that
would offer adequate protection without destroying itself in the protective
process?-C. R. Witherspoon, Omaha,
Nebraska
A. Any power line contains transients, voltage peaks which indeed often
reach 400 volts. These peaks can result
in the producvtion of transient "clicks"
in equipment.
This may surprise you at first, but
look at it again. There are capacitors
in the power supply of your solid-state
gear. When power is first applied,
these capacitors take a charge which is
proportional to the applied voltage.
Further, this charging action takes a
measurable amount of time. Should the
voltage fall somewhat, the capacitors
will discharge into the load, thereby
attempting to maintain the original
charging voltage. If the under-voltage
condition remains for a time, there will
come a point where the original charge
is not sufficient to maintain the original
operating conditions, and the circuit
will then run at reduced voltage.
If the voltage increases rather than
drops, the capacitors will again attempt
to maintain the operating voltage
while they are charging up to the new
voltage. If the transient voltage is of
very short duration (as it would have
to be if we term it "transient"), the
capacitors will not have an opportunity
to obtain even a small fraction of the
charge which would have been required
to raise the voltage applied to the external load. Thus, the power supply
has a built-in protective mechanism.
If you are having trouble with a particular piece of solid-state gear, it may
be the result of poor design, rather
than power-line problems.
My thought is that if you cannot see
the increase in voltage on a voltmeter,
the load presented by our solid-state
gear will not be damaged. This built-in
protective system is all that is required.
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Improvised Heat Sinks
We all know how important it is to
use a heat sink to remove heat from
semiconductor devices when soldering
to the leads. There are commerically
available heat sinks for this purpose.
However, if you do not have such a
device, you still can solder to the semi-
conductor without damaging it if you
use a makeshift one.
For example, you can use an alligator clip. Make sure that it grips the
lead firmly before soldering.
If you don't have an alligator clip,
you can use a pair of tweezers. Use
a strong rubber band to hold them
closed.
If this is unavailable, use a pair of
long -nose pliers. Here again, a rubber
band can be used to hold the pliers
closed.
The main consideration here is that
there be sufficient conductive material
to remove the heat. However, the tip
must be small so it can fit between the
body of the device being installed and
the point on its leads to which solder
is
applied-Name Withheld
Book Review
Reference Data for Radio Engineers.
P. Westman
(technical publications editor) and
Melvin Karsh associate editor). 1150
pages; 1350 illustrations. Howard W.
Sams & Co., Inc., a subsidiary of ITT,
Indianapolis, Ind. $20.00.
Fifth Edition. Ed. by H.
This one -volume reference book is
of immense usefulness. Ask any en-
gineer-radio, electronics, telephony
-who
has one of the previous editions and he'll doubtlessly agree. If
you want to place your finger on a
formula, get a thumbnail sketch of
a special area in electronics or allied fields, the chances are that this
reference volume will provide the
answer.
Greatly enlarged and revised, it
includes seven subject areas that
were not covered by the fourth edition, including space communications and quantum electronics. As
important as the text and generous
number of illustrations is the volume's index and cross-index.
It was all started in 1942 by a British subsidiary of ITT. The first effort
was a 60 -page brochure, published
as a "complete," reliable reference
source for the radio and electronics
engineer. It grew from there to its
present 1150 pages, and from the
looks of things will continue to grow
with succeeding editions. And to
give you some idea about the new
material in the volume (50 per cent
is said to be brand new), stereo FM
was not in the previous edition,
which was published in 1956.
Check No. 4 on Reader Service Card
4
AUDIO
MAY 1969
Because accuracy of
reproduction is essential,
AR -3a speaker systems
are used by
Connoisseur Society.
For their Vienna recording sessions with internationally distinguished Czech pianist
Ivan Moravec, Connoisseur Society brought AR -3a speaker systems from their New York
facility. Earlier recordings by Moravec on Connoisseur Society records have received
awards for outstanding technical and musical excellence. The newest release in the
series is record CS 2010, piano music of Debussy and Ravel.
Acoustic Research makes AR speaker systems, amplifiers and turntables. All are described in our catalog, obtainable for the asking.
ACOUSTIC RESEARCH, INC.,
24
Thorndike Street, Cambridge, Massachusetts 02141
Overseas Inquiries: Write to AR International at above address
Check No. 5 on Reader Service Card
AUDIO
5
MAY 1969
www.americanradiohistory.com
AmericanRadioHistory.Com
IMPROVED
PERFORMANCE!
kHz ±2 dB, channel separation of 30
dB from 30 Hz to 12 kHz and 20 dB
from 12 kHz to 24 kHz. Priced at
What's New
In Audio
$100.00.
Check No. 128 on Reader Service Card
Audio Literature
Tape Recording Ideas and Hints are
outlined in a 35 -page handbook, Brochure A68-151, from the Ampex Corporation.
Check No. 129 on Reader Service Card
NORTRONICS
ANNOUNCES
THE 9000 SERIES
TAPE HEADS
FOR
PROFESSIONAL
New Transcription Turntable
Marketing Industries announces availability of a new turntable,
the Thorens model TD-125. It incorporates an electronic, transistorized
drive system. Among its features are an
electronic speed selector and pitch
control; three speeds; eight -lb., 12 -in.
turntable platter; suspended chassis;
Elpa
STUDIO
EQUIPMENT
Extremely smooth response from
20 Hz to 20 KHz.
Extra wide pole faces for minimum
low frequency contour effects.
Hi -Q, low loss core structures.
Extra deep deposited quartz gaps
for sharp, clean edge definition.
Full gap depth for maximum wear
life.
All metal hyperbolic face for re-
duced oxide loading and intimate
tape contact.
Gap Colinearity-Precise Gap
Alignment For Both Azimuth and
Phase on Multi -Track Heads, either
4 -Channel or 8 -Channel.
synchronous motor; and replaceable
tonearm board for mounting the user's
choice of a tonearm.
Flutter is reported to be .08%. Dimensions are: 18 -in. L x 14 -in. W x
5 -in. H. Weight is 32 lbs. $185.00;
$200.00 with oiled walnut base.
Check No. 127 on Reader Service Card
Interchangeable -Stylus Cartridge
The new ADC 25 stereo pickup includes three easily interchangeable
stylus assemblies: #251 is an elliptical
stylus with a contact radius of .0003"
and a lateral radius of .0007", #252 is
an elliptical stylus with a contact ra-
distributor.
8101 Tenth Avenue North
Minieapolis, Minnesota 55427
Phone: (612) 545-0401
6
Check No. 6 on Reader Service Card
Check No. 130 on Reader Service Card
Primer of Stroboscopy booklet is
available free from the General Radio
Company. It explains fundamental
A
Check No. 131 on Reader Service Cord
Available locally, from your
7/o1rfroni
COMPANY. INC.
chure from Telex Communications,
catalog BI -2166, covers over 30 general
communications and dictation headphones as well as other private listening devices and accessories.
British Valve and Electronic Industry booklet classifies 72 types of devices with the names of the firms
marketing each type. Available free
from the General Secretary, BVA/
VASCA, Mappin House, 4 Winsley St.,
Oxford St., London, WIN ODT.
EMT Wilhelm Franz Products: This
A
MORE CONVENIENT THAN
FACTORY REPLACEMENT
Replace heads in the field, minimum down time. Plug-in simplicity.
No need for a spare nest.
Wide choice of Record, Play, and
Erase Heads, for 1/4 inch, 1/2 inch,
and 1 inch tape, in a variety of
track styles.
Full details in Nortronics Bulletin
7295A, available free on request.
Headphone/Private Listening Bro-
concepts of stroboscopy, accessories for
electronic stroboscope, how it can be
used with a simple camera, and other
applications for the instrument.
and
UNEXCELLED PERFORMANCE IN
AMPEX, SCULLY AND OTHER
PROFESSIONAL RECORDERS
A
dius of .0003" and a lateral radius of
.0009", #253 is a spherical stylus with
a lateral radius of .0006". Each is color
coded. According to the manufacturer,
these styli will enable the user to obtain optimum sound reproduction from
the many record brands available, each
with their individual groove characteristics.
The ADC 25 features a tracking force range from 1/2 gram to 11/4 grams,
frequency response from 10 Hz to 24
pocket -sized catalog, available from
Gotham Audio Corp., provides capsule
data on such products as the EMT140st steel plate reverberation unit,
EMT-930st turntable, and the Studer
A-62 and C-37 master tape recorders.
Check'No. 133 on Reader Service Card
Building loudspeaker enclosures?
Two manuals from JBL offer instructions and hints. CF802, "Enclosure
Construction Manual," discusses the
basics of enclosure design, the ported
enclosure, grille assemblies, typical
cabinet construction, joints, bracing,
and professional finishing techniques.
CF706, entitled "Enclosure Construction for JBL 'F' Series Musical Instrument Speakers," is another manual for
do -it -yourself -ers. Actual dimensions
and port sizes are given for typical
enclosures. 500 each from JBL, 3249
Casitas Avenue, Los Angeles, Calif.
90039.
A 12 -page bulletin from Pittsburgh
Corning Corp. graphically describes its
GEOCOUSTICS® units, designed to improve room acoustics. Information on
how the 131/2 -in. square pads are in-
stalled, together with tables and charts
for estimating the number of units
needed in an area, are included.
Check No. 132 on Reader Service Card
AUDIO
MAY 1969
wilnue: rcvoluliooarY
&iu nil Effect lmplificr.
Unique "S.E.A." Sound Effect Amplifier tone control system of models 5001 and 5003
eliminates conventional bass and treble controls. Provides individual control of the five different
frequencies that comprise the total tonal spectrum; 60, 250, 1000, 5000 and 15000 Hz.
introducing the striking all solid state 60 watt
AM/FM Multiplex Stereo
Tuner Amplifiers, JVC brings the stereo fan a new
dimension in stereo enjoyment-the complete control of sound effects.
This exciting innovation is made possible through
the incorporation of a built-in Sound Effect Amplifier (SEA.), a versatile component that divides the
audio range into five different frequencies. It enables the 5001 and 5003 to be tailored to the acoustical characteristics of any room, or to match the
sound characteristics of any cartridge or speaker
system, functions that were once reserved for expensive studio equipment. But even without the
built-in S.E.A. system, the 5001 and 5003 would be
outstanding values. They offer improved standards
in FM sensitivity and selectivity by utilizing the latest
FET circuitry with four IF limiters in the frontend of
the 5001 and five in the 5003. They both deliver a
wide 20 to 20,000Hz power bandwidth while holding
distortion down to less than 1%. They feature comp etely automatic stereo switching with a separation
figure of better than 35dB. They allow two speaker
In
systems to be used either independently or simul-
5001 and 140 watt 5003
taneously. Indicative of their unchallenged performance is their refined styling. All controls are
arranged for convenient operation. The attractive
black window remains black when the power Is off,
but reveals both dial scales and tuning meter when
the power is on. For the creative stereo fan, the JVC
5001 and 5003 are unquestionably the finest medium
and high powered receivers available today.
For additional information and
JVC
America, Inc.,
a
S
E A
iaa
r
Frequency Control Characteristics
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How the SEA System Works
SOH;
Glance at the two charts appearing on this page. In
looking at the ordinary amplifier frequency characteristics where only bass and treble tone controls
are provided, you can see how response in all frequency ranges at the low and high levels Is clipped
off. Compare this chart with the one showing the
SEA frequency response characteristics, and the
difference is obvious. No clipping occurs in the SEA
system. It offers full control of sound in 60, 250,1,000,
5,000 and 15,000Hz frequency ranges from -10 to
4-10db. For the first time ever, you have the power
to determine the kind of sound you want to hear.
icwOrdinary Amplifier Frequency Characteristic
copy of our new full color catalog write Dept. AM:
Subsidiary of Victor Company of Japan, Ltd., c/o Delmonico International Corp.
5035 56th Road, Maspeth, N.Y. 11378, Subsidiary of TST Industries, Inc.
A
Check No. 7 on Reader Service Card
Manufactured by Victor Company of Japan, Ltd.
AUDIO
MAY 1969
7
Why
a
Servo -Driven
straight-line
arm?
Because the record is cut along
a
straight line.
Because the stylus of the modern
pickup is too compliant to cope
with the inertia and the friction
of prior straight line arms.
Because the Rabco SL -8 does not
"skate" and needs no anti -skating
gadgets.
Why not write for the complete
story on the Rabco SL-8, the
ONLY CORRECT ARM.
RABCO
ROAD,
SILVER SPRING, MARYLAND 20904
11937 TECH
Letters
3.
rate crossover frequency because
of the unavailability of precision,
high -power network components.
Difficulty in providing a well-defined crossover slope because of
the frequency -dependent impedance of the loudspeakers.
Damping -factor limitation imposed by the resistive component
of the elements in series with the
loudspeakers (as distinguished
from the effect previously described which is due to the reactive component.) This is the limiting factor in the pass -band of
the transducer. For example, the
d.c. resistance of a coil in series
with the woofer might be 0.4
ohms; the effective D.F. is then
limited to 10 if the woofer's impedance is 4 ohms. It makes little
difference if the output impedance of the amplifier is .01, .001,
or one nanohm, the D.F. will be
10 regardless of where the magic
damper control on the amplifier
.
Electronic Crossover Networks
I would like to mention several advantages for an electronic crossover in
addition to the ones mentioned in a recent Audioclinic column. The first is
also related to the discussion of damping factors. If any element connected
in series between an amplifier and loudspeaker has a significant impedance
compared to that of the loudspeaker,
it will deteriorate the effective damping factor. In the case of a crossover
network in the speaker line, this effect
occurs near the crossover region and
becomes progressively worse as the
amplifier "sees" less and less of the
loudspeaker load and more of the reactive load of the crossover elements.
This is particularly bad if the crossover slope is gradual because the loudspeakers are still radiating significant
amounts of power well into their stop
band where the effective damping factor is a fraction. I agree with you that
the effects of damping -factor changes
are often subtle, as is the difference between 0.1% and .01% distortion, but
when we have effective damping factors of unity or less, even in a restricted frequency range, I think we may
have cause for worry.
Another advantage I believe to be
important is that the efficiencies of the
midrange and tweeter, which often are
inherently relatively high, need not be
restricted to that of the woofer through
the use of an attenuator (which may
also serve to deteriorate the damping
factors of the midrange and tweeter).
In many low -efficiency loudspeaker
systems, the risk of voltage clipping of
the amplifier occurs as higher -frequency tones "ride" on high -amplitude
low -frequency tones. If the higher frequency is amplified by a separate amplifier, the risk of amplifier clipping
is reduced by having a more efficient
midrange or tweeter transducer, and/
or by the fact that it no longer "rides"
on the low -frequency signal. This attribute is even more valuable if the
amplifier has poor overload characteristics or recovery from clipping as do
several otherwise excellent amplifiers.
Other disadvantages of a passive
crossover network overcome to a large
extent by the use of an electronic crossover are:
1. Inferior transient response caused
by the reactive elements in the
2.
crossover.
Difficulty in providing an accu -
4.
is set.
Finally, I would like to comment on
the phase relationship between highs
and lows. I am not sure whether you
meant that phase relationship was unimportant between highs and lows as
long as it is maintained in both stereophonic channels, or whether you meant
the phase change of the high channel
with frequency should be the same as
the low channel with frequency. If you
meant the latter I agree (almost), but
if the former I would tend to disagree
as follows:
For either type of crossover, electronic or passive, it is possible to provide a flat phase response of 0 degrees;
i.e., no time delay of any frequency
with respect to any other. In both
cases, however, this is possible only
with a 6 dB/octave slope. This may be
verified by summing the transfer functions of the various sections of the network and checking to see that they
add to unity: i.e., the instantaneous
sum of the output voltage should equal
the input voltage at the same instant
for all frequencies. Of course it is assumed that the loudspeakers are phased
to the power amplifier properly. Likewise, it can be shown by the investigation of their transfer functions, that
12 dB/octave networks exhibit either:
A) speakers out of phase 180 degrees
at the crossover frequencies and
no time delay of high frequencies
with respect to low frequencies;
or B) speakers in phase throughout the crossover region, but with
a time delay of the high frequencies relative to lower ones.
(Continued on page 63)
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8
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MAY 1969
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AUDIO
9
MAY 1969
www.americanradiohistory.com
AmericanRadioHistory.Com
31147M1
KniZM
BERT WHYTE
The $$ Crunch in
Classical Recording
FROM THE EARLIEST days of high fidelity, classical recordings have been
used to demonstrate the quality of the
component parts of a music system.
The classical record and, later, the classical tape, were the yardsticks we used
to measure progress in the field. This
was (and is now) not based on snobbishness or any personal bias in favor of
classical music over popular music. The
simple fact is that classical recordings
offer a technical challenge to the performance of a system, while the vast
majority of pop recordings are not of
much use in this respect.
The pop recording has limited dynamic range. On the order of 25 dB or
less, it rarely has any bass response
below 50 Hz, and with its dynamics
permitting very high-level recording
there is usually no problem with signal-to-noise ratio. In these stereo days,
the pop record with its multi-mike,
many -tracked complexities bears no
relation to reality in terms of what you
would hear with the same musicians
on a live basis. The pop record is a
creature of the studio. The stereo perspective is "custom made" to order for
directionality and reverberation content. These are some of the reasons
why some pop artists who made their
reputations on recordings bomb so
badly when they venture into the nightclub circuit. Shorn of their electronic
"crutches," their live performances are
but pale shadows of their phonographic
magnificence. This is also one of the
reasons for the upsurge of interest in
microphones with built-in echo facilities and elaborate sound installations
in night clubs.
There is little doubt that classical recordings made a significant contribution to the early growth of the hi-fi
component market. This in turn, of
10
course, increased the sales of classical
records. While all this is true, it must
be admitted that the pop record market
has always been greater by far than
the classical market. As progress continued in the hi-fi field, some of the
benefits began filtering down to the
"Queen Anne" consoles and the lower priced phonograph equipment of the
mass market. Pop records began to
sound better than ever and sales
boomed. Couple this with the advent of
the "affluent society" and the "youth
revolution" and the growth of the pop
record market became positively spectacular. For quite a few years the classical record market grew slowly, but
steadily, finally reaching a high water
mark when, if I remember correctly, it
constituted 26 per cent of the total
market. From that point there has been
a gradual decline. For about the past
five or six years the classical market
has been more or less static at about
9 to 11 per cent of the total. According
to the RIAA, sales in 1969 should be
close to a billion dollars. Thus the producers of the classical product will
have something on the order of 100
million dollars to share among themselves. This sounds like a lot of money,
but most of the classical marketing people I have talked to have bemoaned the
slimness of their share. They also were
dismayed by the mushrooming competition in the field, the flood of cheap
labels, and the sales plateau on which
they have been perched for the last few
years. In short, they are very unhappy
with the state of the classical record
market.
Why has all this happened? This is
a very complex question, with the answer scattered among many theories
and opinions. One holds that it was the
members of the "Establishment" who
could afford the component hi-fi and
who supported the classical market,
and that this is no longer true. Another
feels that once these people assembled
a "basic" classical library, their acquisition of newer and more adventurous
repertoire was relatively slow. Still
another feels that only the more avid
collectors have enough musical erudition to appreciate and want multiple
versions of standard classics. This is
disputed by a producer who says that
a person will buy a second and third
version of his favorite work if the successive recordings are demonstrably superior from a technical standpoint. Yet
another asks plaintively, "How many
Beethoven 5ths can the market absorb?" He is answered by a producer
who says, "Everytime we have strayed
from the standard repertoire and issued some exotics, it bombed."
The proliferation of new, cheap,
classical labels and the spate of reissues is cited for cutting into the "normal" market. The spokesman for one
of the big record companies says this
could be countered if they could afford
to record new versions of the basic repertoire (and even some "offbeat" material) with the big name artists and
orchestras, replete with all the latest
technical advances. "We are caught in
a profit squeeze," he said, "and in this
country it is now so expensive to record symphonic material that we must
drastically curtail such activity." Other
producers I contacted voiced the same
sentiments: that symphonic recording
in the United States is now almost prohibitively expensive. One candid gentleman said that if it were not for
certain grants and the aid of wealthy
people, even less symphonic recording
would take place. This matter of recording costs has been an issue for
some years now, and is largely responsible for so much symphonic recording
being done abroad, where costs are
considerably lower than in the U.S. In
view of some of the opinions expressed,
one wonders whether lower recording
costs in this country would substantially stimulate the classical market.
Many feel that it would. But in any
case, there is a unanimous condemnation of the cost problem.
What I have recently been told will
not make these classical record producers any happier. The American Federation of Musicians has decided to ask
for a "substantial" increase in the symphonic recording rate; it is said that
negotiations are already underway.
Will this be the last straw? Will there
be a strike, or an embargo on recording? Will the flow of recording to Europe increase dramatically? I wish I
knew the answers to these questions.
However, I have made symphonic recordings in this country and in Europe
and am familiar with costs. Let me give
you an idea of the amount of money
required to record a typical symphony,
both here and abroad.
Let us assume we are recording a
major symphony orchestra. The work
to be recorded can be accomplished
with perhaps 85 musicians, but it is
common practice to augment the
strings so that in this case we have an
even 100 musicians. The basic union
rate is $53.65 per man for a two-hour
session, thus we have an initial outlay
of $5,365.00. However, the amount of
actual music you can put on tape in
those two hours is restricted to 40 minutes. Since many symphonic works are
longer than 40 minutes, you need more
recording time. Even if the work was
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only of 41 -minutes duration, that one
minute over the allowable recording
time must be paid for by going into a
half-hour overtime, which for 100 men
is a matter of $1,341.00. In that halfhour you are allowed to record 20 minutes of music. Theoretically, then, you
could record an hour of music with one
session and a half-hour of overtime. In
practice, this would be a virtual impossibility. It is rarely possible to record a symphony in two sessions with
a half to an hour overtime. Usually it
takes three sessions and perhaps some
overtime. If you are unfortunate
enough to run into artistic or technical
difficulties, the recording might take
four or five sessions. When this happens and you are the recording director, you have the time hanging over
your head like some giant taxi meter
which inexorably ticks away the dollars.
To keep sessions to a minimum,
here is the usual procedure: The director of artists and repertoire has decided what he would like to record with
this particular orchestra and conductor. He clears his choice with the marketing executives in his company and
then consults with the conductor before
the start of a new symphony season.
If all is agreeable, the conductor will
program the work to be recorded.
Sometime during the season, the conductor will rehearse the work to be recorded. He will beg, borrow or steal
all the rehearsal time he can. Then the
work will be played at three, perhaps
even four regular concerts. At this
point, when presumably the orchestra
really has this work down pat, the recording team moves in and usually
records the work the day after the last
concert. In this fashion the work usually gets recorded within three sessions.
With our hypothetical symphony
this would total $16,095.00. If the orchestra is located away from the recording company's home base there are
transportation and expenses for the recording crew. If the hall in which the
orchestra gives its concerts is not suitable for recording, you must rent
another hall at from $500 to $1,500.
The score of your work may call for
instruments not normally owned by the
orchestra to be rented. If you are recording an oratorio or a Beethoven 9th
Symphony-anything that requires a
large chorus-you may have to rent
chairs. If the work you are recording is
not in the public domain you will have
to pay the composer's publishing company a royalty, as well as rent or buy
scores of the work. The musicians
union also requires a certain amount of
money to be paid into what is known
12
as the "performance fund," the proceeds of which are for the aid of indigent musicians. The conductor has a
royalty arrangement, which usually is
5 per cent of the retail list price of the
record (or tape) and he may or may
not require an advance on his royalty.
For some of the really "big shots," the
financial terms are more attractive.
Most contracts with a conductor stipulate that the recording company must
recover the costs of the recording before the royalty payments can commence.
What with one thing and another,
you can readily see that to record a
typical symphony would run from an
almost impossibly low $11,000 to an
average $15,0000 to $18,000, to a not
uncommon $20,000. Needless to say,
the costs for a really big project like a
Mahler 8th Symphony and for many
operas can be astronomical.
Now let us contrast these costs with
a typical symphonic recording in London, using an orchestra of the calibre
of the London Symphony or the London Philharmonic. The British musicians have a rather complicated payment in which rank and file members
of the orchestra get one set fee; what
they call "second principals" get a
higher fee, and "first principals"
(equivalent to our desk men) get a
still higher fee. They also have what is
called a "management fee" of 121/2 per
cent. It all adds up to 700 pounds or
about $1,680 for a three-hour session,
and unless they have changed recently,
within the session you can put 40 minutes of music on tape. Theoretically,
some "cheap and dirty" label could record a 35-40 minute LP for about
$2,000.
It is not likely to happen in this
case for none of the London orchestras
would ally themselves with such a label.
They prefer to contract for a number
of recordings and book the sessions in
blocks. The London orchestras do so
much recording that the men are fabulous sight readers, and they can cope
fairly rapidly with unknown scores. It
is rarely possible to have the same arrangement of performance before recording as in this country. For one
thing, most recording is not done during the regular season. For another,
specific condctors usually are contracted for specific works and it is conceivable that in a block of sessions you may
record with four or five different conductors. In any case, you can record
most symphonic LPs within three sessions, which would cost a little over
$5,000. Most of the "extras" I outlined
for an American recording session apply equally well here, except in most
cases the costs are less in London. One
striking example: the acoustically famous Walthamstow Hall used to rent
about $60. Perhaps it is more now, but
I would bet the increase would be
trifling. Of course, transportation and
living expenses for the recording crew
are going to be higher than in the
U.S., but it isn't all that expensive anymore to fly across the Atlantic. All
costs considered, the total for an LP
would average about $6500 to $7000.
Obviously, it is possible to make at least
two, and oftentimes three recordings in
London for the cost of one in the
United States. This economy is not
lost on American producers, which is
why there is so much recording activity
in London. I should add that recording
costs in several European countries are
substantially less than in London.
No matter what the reasons advanced by the many recording people
I spoke to, it is obvious that the classical record market is not what many
people think it should be. Dollar volume has increased each year, but the
percentage of the total market is static.
It is sheer conjecture whether any of
the remedial measures that have been
suggested would have any salutory effect on the market. Looming ominously
in the near future is the oft -quoted
statistic that half the population of the
country will be under 25 years of age.
This obviously pop -music oriented
group is likely to cut even deeper into
the total record market. The faint hope
of many is that, as maturity comes to
many of the young, they will "discover"
classical music. Perhaps so, but I think
it will take some pretty nifty promotion, on a level that the young can
"dig," to encourage this trend.
In any case, things are bad enough
without the ill-timed quest of the musicians union for an increase in recording
rates. I bow to no one in my admiration for the skills of our symphonic
musicians. Theirs is a most demanding
profession and they work very hard.
But we must remember that they receive a regular salary for their concert
duties. Recording money is strictly
augmentary, a bonus whose size is dependent on how much their orchestra
records. At this critical point in the
classical record business the musicians
could help the business and themselves
by reducing the recording rate, not asking for an increase. What sense does
it make to drive the rate so high that
no one wants to record, or at least severely limits the amount of recording?
Surely, many reduced -rate sessions are
better than a few high-priced sessions.
Let us hope wisdom prevails, or classical recording in this country will beÆ
come moribund.
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Classical
AUDIO MUSIC REVIEW
Record
Reviews
Edward Tatnall Canby
Revaluing the
Twentieth Century
Boulez Conducts Stravinsky Firebird Suite,
Bartók Music for Strings, Percussion, and
Celesta. BBC Symphony Orch. Columbia
MS 7206 stereo ($5.95)
My ears perk up whenever a Bartók
or early-Stravinsky recording appears:
Both composers' works, ultra-modern
and at the same time full of traditional
Romanticism, are subject to astonishingly varying emphasis in the interpretation. Moreover, there are often quite
different versions, to begin with. This
applies to both works on this dynamic
new recording the young French conductor -composer whose touch seems to
transform almost any music he works
on.
The Firebird music exists in numerous formats. There is the original ballet,
the much-reduced orchestral suite
form, the original thick scoring and the
Stravinsky -produced revisions of much
later years. As an early work it is full
of late -Romantic effects, but also of
astonishing modernisms. Boulez, paradoxically, chooses here the original
suite, in the older and fuller scoring,
then proceeds to make it sound newer.
He rips along, playing down the great
Romantic climaxes that once made
Firebird the best -loved "modern" piece
among our parents and grandparents,
building up the modern instrumental
effects and bizarre harmonies. This version, moreover, leaves out two familiar
numbers, the Berceuse and the longwinded (I always thought) Finale
though that ending was, if I am right,
a later addition by Stravinsky.
All in all, this is a very novel sort
of Firebird and a worthwhile one to
add to any Firebird collection. Be sure
to try, also, Stravinsky's own complete
ballet version, the one with the strange
and unfamiliar connective tissue that
carries on the stage action between the
big set pieces. Oddly, the most modern sounding music in the work is this inbetween material, left out of the Suites.
Stravinsky composed it in later years,
to join up the earlier segments.
-
14
Classical
14
Jazz
58
Light Listening
60
Tape Reviews
62
As for Bartók's 1937 masterpiece of
controlled fury, it also comes in two
versions, one for single strings, a
"chamber" work, and the other with
string orchestra. Boulez, using the big
version, once more manages to combine
elements of both. The taut, disciplined,
rapid playing de-emphasizes the Romantic elements that are, as always,
still latent, thereby giving the piece a
more chamber -like sound than in other
more opulent orchestral versions.
As Boulez says, the composer proposes, the listener
the performer
disposes. This is only one way to do the
music. Try RCA's early -stereo Reiner
version for a wholly different sound,
for example. But the Boulez approach
is a valuable one, and particularly in
recorded form-this being one of the
most horribly thorny scores ever to face
up to the microphone and tape recorder. Boulez definitely helps with its
major problems-the long, ultra -pianissimo opening for murmuring strings,
where the ear is unable to "set level"
(Boulez plays it louder and faster than
many others), the much -delayed explosive entrance of full percussion,
piano, xylophone and celesta, then the
wispy middle movement with its almost
inaudible xylophone pings, down dangerously near the "mud" level and
finally, the sudden violence of the racing last movement, back to maximum
level and maximum transient explo-
-
-
siveness.
Some score!
Worth having a dozen
versions in your record library just to
see how differently the performers, on
the one hand, and the engineers, on the
other, have faced up to Bartók's challenging "proposals."
Performances:
A-
Sound: A-
Stravinsky: The Rite of Spring; Fireworks.
Chicago Symphony, Ozawa. RCA Victor
LSC 3026 stereo ($5.98)
Here's another famous early 20th
century work that is peculiarly subject
since it,
to changing interpretations
too, combines the radically new with
-
many elements of traditional symphonic music, as we see it today. Most
past versions of the piece are on the
monumental side, heavily stressing the
extreme dissonance, the ponderous savagery of the famed Stravinsky pagan
rites. In its own day, and until recently,
the violent clashes of sound on sound
in this score were unbelievable to many
ears, and to the performing musicians
themselves. And that was what we
heard-we could almost sense the players' own shock as grating clashes
hurtled forth from their surprised ensemble.
Now, those dissonances are not only
a bit old fashioned.
So two instruments play along together
in minor seconds, curdlingly dissonant?
Now, they do it with the utmost calm,
for the effect is easy and familiar. We
can hear that, too.
The youngish, long-haired Japanese
conductor, Seiji Osawa, is very much
a part of this new attitude. His "Sacre"
is almost casual in its neatly tailored
treatment of the well known dissonance. No longer is there that great,
hideous groaning and grunting, no
longer the sense of shock communicated from the musicians themselves.
Instead, we have an almost Mozartean
classicism, an impeccably light, accurate, -polished playing, moving rapidly
along, clean-cut instead of rough hewn.
There is, even, a bit of the Japanese
in it. Chicago!! Who'd a' thunk it.
Appropriately, the dissonant texture
of the piece is not a bit diminished. It
is merely cleaner, more practiced, perhaps even more effective for being
taken for granted. The RCA recording
is somehow related to all this, a clean,
concentrated sound on the dead side,
almost intimate.
The dividend piece, the short early
Fireworks, comes first, at the beginning
of Side 1. Good. It would be an anticlimax coming last.
familiar but even
Performance: B+
Sound: B+
(Continued on page 56)
AUDIO
MAY 1969
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Check No. 15 on Reader Service Card
MAY 1969
15
www.americanradiohistory.com
AmericanRadioHistory.Com
Tape Guide
HERMAN BURSTEIN
Microphone Wind Screen
Q. A few months ago I purchased a
battery -operated tape recorder, principally for foreign -language practice.
Somewhat to my surprise, this little
machine has proved to be adequate for
another hobby of mine, which is recording of sound of trains. However,
the microphone is quite susceptible to
wind noises. Can you recommend a
microphone which is reasonably immune to wind noise?-Ralph Brunson,
Lubbock, Texas.
A. Most manufacturers of microphones make units equipped with a
screen to diminish wind noise. Also,
some furnish a screen as an accessory.
I cannot recommend a specific microphone. I suggest that you write to several microphone manufacturers for recommendations as to their respective
units which can meet your needs, at a
price within the range you care to
spend.
High -Speed Duplication
Q. There has long been a question
that I have wondered about. In recording from pre-recorded tapes made at
3.75 ips, would there be a decisive advantage to play this tape at 7.5 ips
and record from it at this same speed?
This is apart from the shorter time to
duplicate the tape. Of course the duplication would be done with two tape
machines of comparable quality.
James W. Larsen, Camp Lejeune, N.C.
A. I do not know of any decisive advantage in copying a 3.75-ips tape at
7.5 ips, other than the saving in time.
Rather, there is a question whether
this produces as good a duplicate tape
as copying at the 3.75-ips speed. The
answer is not clear, and quite a few,
based on experience, claim that the results are about as good or nearly as
good when copying at 7.5 ips as when
copying at 3.75 ips (assuming, of
course one is dealing with a tape originally recorded at 3.75 ips)
Theoretically, there is a disadvantage in copying at 7.5 ips. When a 3.75ips tape is sped up to 7.5 ips, all frequencies are doubled. Thus a 12,000 -
-
.
Hz frequency becomes a 24,000 -Hz one.
The question then is whether the electronics of the playback and recording
machines can handle the highest
(stepped up) frequencies. There is
also the increased possibility of beating
between audio frequencies and the bias
frequency. Ideally, the bias frequency
should be at least 5 times as great as
the highest audio frequency. But if all
audio frequencies are doubled, there is
less apt to be such a margin, with a resulting increase in the likelihood of
"beating," manifesting as noise. Finally, there is increased possibility of
tape distortion, owing to treble emphasis in the recording process being applied to stepped -up frequencies of con-
siderable magnitude.
The best answer you can obtain is
through practical experience. Try copying at both speeds on the same reel
of duplicate tape, and note whether
there is an audible difference.
Excessive Noise Level?
Q. With the playback gain control
set at maximum, my tape machine produces what seems to me to be an excessive amount of noise. How can I
check this?-Richard Firtik, Mountain
View, Calif.
A. Some tape machines aim at maximum output of as little as about 0.5
volt, while others go as high as about
5 volts-a difference of some 20 dB.
And, everything else being the same,
the 5-volt machine will also produce 20
dB more noise. Possibly yours is a
high -output machine, with a signal-tonoise ratio that is nevertheless satisfactory. I suggest you do the following.
Obtain a pre-recorded tape or record a
tape on your machine. Play it back on
your machine and note the noise level.
Play it back on a comparison machine
(perhaps a friend's) that you know to
be of high quality. If playback noise is
about the same for each machine, with
the audio signal at equal levels, then
your machine's signal-to-noise ratio
would appear satisfactory.
Monitoring the Tape
Q. I make live recordings and have
wondered how I may monitor my tapes
during recording.-John Eshia, New
Britain, Conn.
A. You must have a tape recorder
designed for monitoring, that is, one
with separate record and playback
heads and also with separate record
and playback amplifiers, so that you
can simultaneously record the tape and
play it back. Further, you must have
an amplifier with a monitoring facility,
so that it can switch between the in-
coming signal (which is also being fed
by the amplifier to the tape recorder)
and the tape recorder's playback signal. In the absence of a monitoring
facility in your amplifier, you can monitor directly from the tape recorder's
output jack, provided that this is of
low impedance. You can connect high impedance headphones to this jack. Or
you can use a low -impedance headphone in conjunction with a step-up
transformer in order to improve the
match between the headphone and the
tape recorder output.
Setting Bias
Q. I would appreciate any comments
you might have on the proper setting
of bias in a tape recorder. At 3.75 ips
I feed in a 1000 -Hz signal at 15 dB below 0 VU level. Using a VTVM, I
read the playback output at my speaker terminal. If 0 VU =. 100, then the
maximum output as I adjust bias is
at 70, using a high -quality tape. But
then the sound comes out definitely
tinny. However, for the tape I am using, the instruction book for my tape
recorder says I should set bias to read
0 VU in playback. But I cannot reach
0 VU. I would also like to know if
there is any way that I can measure
distortion. While I do not have distortion -measuring equipment, if I knew
where distortion was lowest as I adjust bias, this would be most helpful.
-Dennis S. Furbush, Flushing, N. Y.
A. In the better tape machines it is
often the practice to adjust bias until
maximum output is achieved at a frequency such as 1000 or 500 Hz, depending on tape speed (keep in mind
that a 1000 -Hz frequency at 7.5 ips
has the same wavelength as 500 Hz at
3.75 ips) ; and then increase bias so the
output drops about 1/2 dB. It would
seem, therefore, that you should increase bias past the point where you
set it.
To measure distortion-usually it is
harmonic distortion that is measured
in a tape recorder-you need a 400 Hz signal source and a harmonic distortion meter. In general terms, bias
increase causes distortion to drop at
first, but eventually to rise. The bias
employed in a tape machine usually
represents a compromise among conflicting requirements of extended treble
response (calling for reduced bias),
low distortion (calling for increased
bias) and low noise. At speeds of 7.5
and 3.75 ips. it is usually necessary to
use less bias than would result in
minimum distortion, thereby permitting extended treble response to be
attained.
,
Check No. 17 on Reader Service Card
16
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AmericanRadioHistory.Com
-*
Music lovers, take control!
Specs You Can Brag About. Frequency response: 20-22,000 Hz
@ 71 ips, 20-17,000 Hz @ 33/4, 2010,000 Hz @ 1/8. Wow and flutter:
0.09%. Signal-to-noise ratio: 52 db.
Three Heads. Allows monitoring of
either input source or the actual
recording made on the tape.
Professional Slide
Non -Magnetizing Record
Head. Head magnetization
build-up, the most common
cause of tape hiss, is eliminated by an exclusive Sony
circuit which prevents any
transient bias surge to the
record head.
Controls. Two fingertip controls are posi-
tioned vertically side
for immediate
by side
precision adjustment of
recording volume. Easi-
er to read, easier to
establish interchannel
volume relationship than
with conventional knobs.
Noise -Suppressor Switch.
Full -Size Professional VU
Meters.These internally lighted
Special filter eliminates
undesirable hiss that may
instruments provide the precision metering for really serious
recording. Calibrated to NAB
standards.
exist on pre-recorded tapes.
Built-in Sound -on -Sound and
Echo. Switching networks on the
front panel facilitate professional
echo and multiple sound -on sound recordings without requiring external patch cords and
mixer.
Sony Model 630-D Solid -State
Stereo Tape Deck. Buy it for less
than $299.50, complete with
handsome walnut base and dust
cover. Also available: The Sony
Model 630 Solid -State Three Head Professional Stereo Tape
System, with stereo control cen-
ter, stereo power amplifiers,
More Sony Excellence. Ultra -high -frequency bias.
(Sony achieves lowest recording distortion thn-ougn
use of ultra -high bias frequency -160 KHz!)
Scrape flutter filter eliminates tape modulation distortion. Automatic shut-off. Pause control with
lock. Vibration -free motor. Four -digit tape counter.
Automatic tape lifters for fast -forward and rewind
reduce head wear. Retractomatic pinch roller for
easy tape threading. Variety of inputs and outputs.
Vertical or horizontal operation.
=1969,SUPERSCOPE.INC.
microphones, and lid -integrated
full -range stereo extension
speakers, for less than $449.50.
For a free copy of our latest catalog, please write Mr. Phillips,
Sony/ Superscope, 8142 Vineland Avenue, Sun Valley, California 91352.
SONY
SUPER COPE
You never heard it so good.
manufacturing arm of the company, will find easier
sledding for its cassette machines when the company backs the concept with its pre-recorded
cartridges.
EDITOR' S
RliVIEW
Wild Sounds
Multi -Vider, a $244.50 four -octave electronic
device for wind instruments, developed by the
Conn Band Instrument Company, has assisted in
producing some of the wild sounds heard in some
Classical Music for the Rock Set
Mahler with psychedelic lights! A recital on the
Baldwin Electronic Concert Grand Piano! That's
the way it was last month in Philadelphia and
New York City, respectively.
In Philadelphia's Electric Factory, a local
discotheque, Mahler's Symphony No. 3 premiered
with psychedelic lighting.The orchestra, baritone,
choral groups, and dancers wore black turtleneck
shirts and slacks. The presentation had a two -fold
purpose: to introduce classical music to young
people in an environment that isn't forbidding
(... "many of them would be hesitant to go to
the Academy ...") , and to allow performers to
feel exhilarated by what they play. In New York
City's Fillmore East Auditorium, the Nety York
Times reported that Lorin Hollander played a
recital (Bach, Prokofiev, Ravel, Debussy, and
Schubert) on a Baldwin Electronic Concert Grand
Piano. Mr. Hollander wore a sleeveless leather
coat of mod cut, with black sweater and pants.
The decision to hold the concert in "the very lair
of rock" was apparently made because "young
people are reluctant these days to go to the marble
mountain at Lincoln Center."
As the man on the video tube says, "Very Interesting."
Cassette Concept Strengthened
In a surprise move, RCA-who, with the assistance of Lear Jet and the Ford Motor Company,
introduced eight-track stereo cartridges announced that they will now market pre-recorded
cassettes. Columbia Records followed on the heels
of this announcement with a similar statement.
Thus, the last two major holdouts in the pre-recorded cassette field joined the fold.
This doesn't indicate that eight -track stereo
cartridge sales have slipped. In truth, they are
skyrocketing. It simply indicates that RCA and
Columbia Records want a piece of the action in
the pre-recorded cassette field, which is also enjoying great sales. Furthermore, RCA's home entertainment division, the consumer equipment
-
18
motion pictures, pop records, and TV commercials, as well as on some "live" club dates. (See
photo of trombonist Buddy Morrow using the
device.)
With the use of a pushbutton control and dynamic volume control, wind -instrument musicians
can get, in addition to the note they play, sub bass, bass, and soprano octaves that can be used
separately or in any combination. The new musical sounds and effects it provides was used by Don
Ellis (trumpet) during the final chase scene in
"Rosemary's Baby" and in his LP album, "Shock
Treatment," and by Frank Rosolino (trombone) in
the sound track of "In Cold Blood," and by West Coaster Tommy Scott on five of eight cuts on his
new album "Honeysuckle Breeze" (Impulse -ABC
Records).
The list of
musicians
using the
Multi-Vider
for electronic
wind music is
said to be
growing.
Soon you
won't be
able to tell a
bassoon from
a clarinet on
sub -bass
octave.
Show -Time News
England's Audio Fair will be displaced by a new
show, the International Audio and Photo -Cine
Fairs. As the name indicates, this is to be a joint
venture designed to appeal to both hi-fi enthusiasts and photography hobbyists. Sounds like a
natural, since so many hi-fi buffs are also camera
"bugs." If you're London -bound in the fall, the
show will be held from October 16-21 in the
National Hall, Olympia, London.
The third annual Consumer Electronics Show
for the industry will be held June 15-18 at the
New York Hilton and Americana Hotels in New
York City.
A.P.S.
AUDIO
MAY 1969
Words are inherently limited in stimulating
the emotions aroused by music. This is especially so
in describing how high fidelity components perform.
With cartridges, for example, we speak of
flat frequency response, high compliance,
low mass, stereo separation. Words like these
enlighten the technically minded. But they do
little or nothing for those who seek only
the sheer pleasure of listening.
We kept both aspects in mind when developing
the XV -15 series of cartridges. We made the
technical measurements. And we listened.
We listened especially for the ability of
these cartridges to reproduce the entire range
Check No. 19 on Reader Service Card
AUDIO
MAY 1969
PHOTOGRAPH OY ROANE GDSOM
instrument. With no loss of power.
In the case of strings, this meant a cartridge
that could recreate the exact nuances that distinguish
a violin from a viola. A mandolin from a
lute. A cello in its lower register from a double bass
in its higher register.
We call this achievement "100% string power."
When you play your records with an XV -15, you won't be
concerned with even that simple phrase.
Instead, you'll just feel and enjoy the renewed experience
of what high fidelity is really all about.
of every
PICKERING
THE NEW PICKERING XV15/750E.
PREMIER MODEL OF THE XV -15 SERIES.TRACKS AT 'h T0 1 GRAM. DYNAMIC COUPLING FACTOR OF 750 FOR
USE IN FINEST TONEARMS. $60.00. OTHER XV-15,CARTRIDGES FROM $29.95. PICKERING & CO.,PLAINVIEW, L.I., N.Y.
19
Oni their sound
The P ilharmonic they're not. Joyful noisemakers
is real y more like it. But that's between them,
the r . udio engineer and the lamppost. On tape
they and strictly euphonious.
Bet een us, the unsung hero is the guy at the
contrls. Plus the compact, uncomplicated
noise--limination system with a small price tag
and a ig name. The Model 123 Graphic Frequency
Respo se Equalizer.
It di ides the audio spectrum into 36 critical
band idths for matchless selectivity in separating
s
u -wanted
sounds from any program.
ArIJ your program material suffers
nor_ in the least.
There's much, much more ... like
se active emphasis. Read all about it.
Or better yet, hear the 123 in action.
A iuick call or note is all it takes.
i
$
B
Brae1
Sr,
INSTRLTMBNTS. INC.
Kjaer Precision Instruments
Cleveland, Ohio 44142
5111 West 164th Street
Telephone: (216) 267-4800 TWX: (810) 421-8266
a
"pop"; recording
sessiono,M
or so before the first recording session of a new song
with singer Peggy March, a
series of informal meetings were
held with the Producer, Pierre
Maheu, and Composer-Arranger
Holdridge to map out the various
recording details. Discussed were:
choice of studio, tape format, placement of musicians, and selection of
microphones.
It was decided right at the beginning to record on 8 -track one -inch
magnetic tape. This might seem extravagant considering that the final
product, although richly orchestrated, contained no special effects
that might demand multi -track techniques. However, the multi -track
recorder is turning out to be a valuable tool for even the most straightforward of sessions.
At best, a phonograph record is a
simulation of the real thing-a live
performance. And, as good as records have become, they still lack
some of the ingredients of the live
performance. To help compensate
for these missing ingredients, the
record must try to achieve a level of
excellence, within its accepted limitations, that might not be realizable
at an actual performance. The record's medium is sound, and sound
only. There is no visual stimulation,
nor is there that two-way communication between artist and audience
that contributes so much to the live
performance's atmosphere. The record audience sits at home, separated
by time and space from the artist,
and with no visual or atmospheric
stimulation, concentrates on one
thing: How does it sound? Mistakes
that might pass unnoticed in the
concert hall will be noticed after a
few playings of a disc at home.
At the concert hall, it is also possible that you may not hear the
proper proportion of, say, drums,
and yet due to the stimulation of the
actual performance, you may not
actually notice the deficiency until
AWEEK
F
woaoM
Singer Peggy March visited the RCA Victor Studios in New
York City to record a new song, called Purple Hat. Here is
a description of the session-from the point of view of the
Recording Engineer.
i
chestra must never overpower, nor
be overpowered by the soloist.
Which brings us to the orchestration for the Peggy March session,
and, I hope, a passable defense of
multi -track recording. The finished
product will contain, in addition to
the voice of Miss March, the sound
of:
16 violins
1
piccolo
4 violas
2
6 celli
1
4 french horns
4 trumpets
1
guitars
piano
Fender bass
drums
tambourine
4
1
1-The author at the control console,
with producer Pierre Maheu at his right,
and singer Peggy March in the background
studying the score.
Fig.
the man in the next seat (who happens to be a drum connoisseur)
points it out to you during the intermission. By then it is too late, and
with apologies to drummers everywhere, it probably didn't affect your
total enjoyment that much anyway.
But when you play a record at home,
you expect to be able to hear the
drums-and every other instrument
all times. Not too loud, of
course, but in the proper balance despite the fact that the sound is now
coming from two speakers, rather
than from a three-dimensional orchestra spread across a large stage.
And in addition to a good balance
within the orchestra, the whole or-
-at
Check No. 20 on Reader Service Card
trombones
flute
1
1
It would be possible to bring all
these musicians into the studio, set
up a couple of microphones, and record the entire ensemble at one time.
In the past, all recording was done
in this manner. However, this technique leaves little margin for error
or for changes in judgment. If, on
listening to a reference lacquer at a
relatively peaceful after-session review meeting, it is found that more
drums are needed, there is nothing
much that can be done about it. One
is more or less stuck with whatever
balance (or lack of it) was achieved
during the actual session. Also, there
would be no such thing as adding a
little more reverberation to the violins only.
During such a session there would
be little that could be done in the
way of selective equalization, limiting, and so forth, since one microphone picks up so many instrument
families. One obvious improvement
is the multiple -microphone technique. If many microphones are
used at fairly close range, the Recording Engineer can exercise
greater control over the sound of
the various instruments. The violin
microphones alone can be fed into
21
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AmericanRadioHistory.Com
a
"pop" recording session
an eche chamber, the drum microphones through a limiter, and so on.
And since the "Universal Microphone" is still waiting to be invented, each instrument can be recorded with the type of microphone
thought best suited for it.
And now we add multi -track recording. With a modern 8 -track (or
more) recorder, we can put each set,
or type of instrument on its own
separate track. Now, long after the
session is over, we can balance the
tracks, listen, and if we care to, rebalance. In re -mixing later, reverberation can be added to a section,
and then removed if it is not satisfactory. In short, many decisions
that had to be made irrevocably during the actual recording session can
now be deferred. Thus the multitrack technique becomes a valuable
tool for almost any type of session.
Some may say that it is just a
sophisticated cop-out for Engineers
who can't get a good mix during the
tension of a session. No doubt it
works out this way sometimes, but
to ignore its obvious advantages because of an occasional misuse is unrealistic. Anyone want to fly with
an airline that passes off radar as a
gimmick for pilots who don't know
their way around foggy skies?
Multi -track recording is here to
stay, of course, and the only question that has not yet been finally
continued
answered is: How multi shall we
eventually get? For the Peggy
March session the answer was 8
tracks.
After going over the score with
composer-arranger Holdridge, the
following track layout was worked
out:
5. Fender Bass
1. Vocalist
2. Lead Guitar
6. Brass Section
3. Rhythm Guitar 7. String Section
& Piano
8. Brass & Strings,
doubled
4. Drums,
Tambourine
It might seem a little unbalanced
to allot one track to one guitar while
putting an entire string section on
another. However, tracks are rarely
assigned to achieve a numerical balance. Rather, different types of
sounds are assigned to their own respective tracks. The lead guitar-an
important part of the score-is put
on its own track. The subordinate
Rhythm Guitar and Piano are
placed together on one track. The
Fender Bass could be placed on a
track with, say, the drums, but since
a separate track was available, it
was used so that later on (during remixing to two tracks for stereo records) the Bass could be individually
treated. On some high-level passages, the lower notes of the Fender
Bass can cause excessive vertical
groove excursion when a stereo disc
is made. This happens in tape -to-
Fig. 2-Conductor-composer Lee Holdridge and a few members of the rhythm section are
shown here amid the usual clutter of cables, booms, and amplifiers.
disc transfer when the bass is put on
either the extreme right or left side.
The problem may be solved mechanically by putting the bass equally on
both tracks, with the result that the
bass sounds as though it is dead
center, the usual position for the
soloist, and somewhat of an artistic
compromise. To solve this problem,
the bass track is first fed through a
dividing network having a crossover
frequency in the neighborhood of
middle C (261.6 Hz). During remix, the section below C is fed in
equal proportion to both sides. The
above -C portion is fed to one side
only-the side from which the bass
is to seem to originate.
The above -C portion contains the
overtones and the instrument's
string noises. Although these sounds
contain relatively little volume, the
ear is so distracted by them, that
the below -C portion coming from the
other speaker is no longer consciously heard. The ear focuses on
that below-C portion originating
from the speaker containing the additional above -C sounds. Although
most of the bass signal is on both
sides of the groove, thereby minimizing vertical groove excursion on the
disc, the ear "thinks" the bass is
coming only from one side, thus
satisfying artistic requirements. Of
course, this treatment can only bé
used if the bass has been recorded
on its own track.
Before going further, we can now
point out another advantage of the
multi -track process. If musical considerations permit, we do not have
to record all the instruments simultaneously. Theoretically, we could
record one track at a time. However,
this would remove all sense of spontaneity from the finished product. A
common practice is to divide a song,
orchestrally, in two. On the first session, the rhythm or basic tracks are
recorded. Later on, during a socalled "Sweetening Session," the
strings, brass, and special effects
(if any) are added. On the Peggy
March session the music was divided
using the following basic tracks:
1.
2.
3.
4.
5.
Peggy
Lead Guitar
Rhythm Guitar and Piano
Drums, Tambourine
Fender Bass
Tracks 6, 7, and 8 were enumerated
earlier.
Check No. 23 on Render Service Card
-p'
w1111wiwwww
-,
W. A. L. 1408083-6
THE "THREE IN ONE" CONSOLE
This is a 14 input, 8 track, live recording console. Each of the 14 input positions has its own slide
attenuator, program equalizer, echo -send control, special effects insertion, pre/post echo switch
and mic./line input attenuator. In addition, there is an eight position illuminated engraved
color -coded output track selector switch panel which switches both direct and echo -send outputs.
Each of the eight output tracks has its own master echo -send control, edgewise mounted echo send V.U. meter, master record level slide attenuator, and a separate echo return control for
both the internal reverb system and your choice of external echo devices.
z
This is also an 8 input, 3 track remix console. Each of the 8 input positions has the same function
controls as the 14 live input positions except that the output selector switch panel is limited to
three positions. One position is for monaural and the other two for stereo. The monaural output
also drives a stereo pan pot. A fourth output can be ordered to drive a second stereo pan pot and
facilitate mixing down from 8 track to 4 track. Each of the 3 or 4 output tracks has its own internal and external echo -send and return controls and meter as in the live recording section of the
"Three in One" Console. This remix console allows simultanous remixes with Eq. and Echo during
live recording and playback for sample mix and monitor purposes.
This is also a self-contained recording studio in one package, incorporating these built-in features
and functions; Four 120 Watt per channel solid state monitor and playback power amplifiers,
Eleven reverb systems. Langevin Graphic Equalizer with special effects switching panel, Playback
and monitor control module, Talkback, Slating, Cueing, Special Effects, and Test Tone circuits,
plus optional tape recorder direction and Master/Sync. remote controls, patch panel, compressors,
and limiters. All inputs and outputs are terminated on a rear mounted Cannon Connector panel.
All you need in addition to our "Three in One" Console is recorders,
microphones, and speakers ... and you are in business!
Write or phone W.A.L. for complete "iterature on the W.A.L.
1408083-6, other W.A.L. Recording Consoles, and audio
components. Quotations on 4,
12, 16 and 24 track Consoles
are available on request.
WIEGAND
C
Aiel60
LABORATORIES
INCORPORATED
3402 WINDSOR ROAD WALL, NEW JERSEY 07719
PHONE: (201) 681-6443
www.americanradiohistory.com
AmericanRadioHistory.Com
a
"pop" recording session
Source
Peggy March
Lead Guitar
Rhythm Guitar
Piano
Drums
Bass Drum
Tambourine
Fender Bass
continued
Microphone
Model
Type
Neumann
67
546
Shure
546
1 Shure
2 Sennheiser
404
56
1 Neumann
67
1 Neumann
1 Electro -Voice
RE -15
421
1 Sennheiser
None (direct pickup off amplifier's Ext. Ampl.
through matching transformer to 150 -ohm mic
1
1
Microphone selection turned out
to be a combination of advance selection and on-the -spot changes. By
the time we were into the final takes,
the microphone layout was as outlined above.
This is certainly not a universal
microphone list. It's just a catalog
of what worked for us on this particular session.
As can be seen from the photos,
baffles were used around each instrument to minimize "leakage" from
one instrument into the microphone
that's in front of another. For further control, the vocalist was
"locked up" in an isolation booth to
permit the almost total isolation of
her track. It is often necessary during re-mixing to raise the level of
the soloist's track so that she is not
drowned out by the full orchestra.
If, during recording, her microphone
has picked up some of the sounds
of the accompanists, then as her
track is raised during the re-mix,
the accompaniment leaking into her
microphone comes up too. Not much
of course, but often enough to
change the overall sound quality.
In the isolation booth, the vocalist can barely hear the orchestra,
and they can't hear her at all, which
is sort of a hang-up if you're trying to accompany someone. So -o -o,
everybody gets earphones. In the
Control Room, we combine all the
microphones into the Earphone
Monitor Circuit. Now our soloist can
hear the band, they can hear her,
the microphones "hear" only their
assigned instruments, and everyone's relatively happy. After a few
"takes" we get our "Basic" tracks
recorded to everyone's satisfaction.
The musicians are dismissed and the
Recording Engineer and his assistant, the Technician, are left to "tear
down" the microphones and wrap up
the cables.
Condenser
Dynamic
Dynamic
Condenser
Condenser
Condenser
Dynamic
Dynamic
output jack
line).
The next step takes place a few
days later when the String and Brass
players come in for the "Sweetening
Session." The set-up is:
Instruments
1
French Horns
Trumpets
Trombones
Flute
1
Piccolo
2
2
2
Track 6
Microphones
2
2
2
1
1
Sennheiser 421
Shure 546
Electro -Voice RE -15
Neumann 67
Neumann 67
Track 7
Instruments
Microphones
8 Violins
2 Violas
3 Celli
4
1
2
Neumann 56
Neumann 56
RCA 77 DX
Once again the earphones come
out and the basic tracks are played
back to the musicians in the studio.
On the sweetening session, the socalled Sel-Sync technique is used. In
this process, the previously recorded
basic tracks are played back using
the first five tracks of the Record
Head Stack, rather than the usual
Playback Head. While playing back
3-AI Rogers on drums. A Neumann
model 67 is used here over the cymbals,
with a Neumann model 56 to capture
snare -drum sounds.
Fig.
tracks 1 to 5 over the Record Head,
tracks 6 & 7 of the same Record
Head record the Brass and Strings.
Thus the Head stack is performing a
dual function. The reason? To keep
the new "sweetening" tracks in -sync
on the tape with the basics. Since
the regular Playback Head is a few
inches removed from the Record
Head, there is a slight delay from
the time a signal is recorded until it
reaches the Playback Head. If the
new tracks are recorded in time with
the old tracks (as monitored from
the Playback Head) all new material will go on the tape a few inches
removed from the corresponding
basic tracks, hence the out-of-sync
situation. By monitoring from the
Record Head, the new tracks are recorded physically in-sync with the
old,
Of course it's a good idea to make
sure the Record function on the previously recorded tracks has been
turned off before the "Record" button is pushed, since a lot of otherwise placid people get very emo-
tional if the basics are erased (no
matter how neatly) during a Sweetening Session.
Anyway, we managed to get
tracks 6 and 7 recorded in-sync, and
without any disasters. These tracks
were now also switched to the SelSync position and fed back to the
musicians, who re-played their parts
in time with tracks 6 and 7. This
time the entire Brass and String sections were 'combined onto Track 8,
giving us a final product containing
one track of Brass, one track of
Strings, and one track with a new
combined Brass and String Section.
This double track enables us to get
the effect of a much larger Brass and
String section than was actually
used. And for stereo, it is possible to
achieve a large overall Brass/String
sound and also put occasional directional emphasis on either Brass or
Strings, as required.
A few days later, the complete
8 -track tape was "mixed down" to
a single-track 1/4" tape, which will
be used for tape-to -disc transfer to
a 45 RPM record. A similar two track version may also be made if
it is decided to include the song in a
future stereo LP album. This "Mix Down" process, often quite involved,
will be covered next month.
AUDIO
24
www.americanradiohistory.com
AmericanRadioHistory.Com
MAY 1969
"We depend on the Dolby System for noise -free,
low distortion classical tape masters, says Israel
The Dolby A-301
Horowitz, Director of Classical Artists
and Repertoire and W. L. Barneke,
Executive Engineer of Decca Records,
New York.
"The noise reduction qualities of the
Dolby System are well-known", says
Mr. Barneke, "but equally important
is that Dolby processed tapes have a
cleanness and lack of distortion that
greatly enhances the realism of our
classical productions."
Pop or classical, rock or Rachmaninoff, you can make superior tape masters with the dependable Dolby System.
DOLBY LABORATORIES INC.
333 Avenue of the Americas, New York, N.Y. 10014 C]
AUDIO
MAY 1969
Telephone (212) 243-2525 H; Cable: Dolbylabs New York
Check No. 25 on Reader Service Card
25
Crossover
Distortion in
Transistor
Power
Amplifiers
JAMES BONGIORNO*
The author examines the
cause and effect of crossover
or "notch" distortion in a
power amplifier's
output stage
in transistor ized amplifiers has been recognized for more than a decade now.
In the early days of solid-state amplifiers it manifested itself as brittle,
irritating music reproduction.
In addition, laboratory measurements revealed higher distortion at low
listening levels when compared with
high listening levels. This was contrary
to experience with vacuum -tubed amplifiers, where it was axiomatic that the
lower the power used, the lower the
distortion. This type of distortion appears as a non-linear transfer of a
signal when it is near the zero axis.
One of the difficulties that faced power
amplifier designers a few years back
was due to transistor devices that were
extremely non-linear at low collector
currents. This non -linearity could be
CROSSOVER DISTORTION
termed Vbe and beta dropout. For example, in a single -diffused device such
as a 2N3055, my spec sheet (see Fig.
1B) stops the beta curve at 80 mA.
Much better devices are available today. And there's one type, not much
used in consumer products, that seems
to be attracting the attention of design
engineers the triple -diffused planar
power transistor. This one wins the
most -linear -device contest hands down,
but the present cost is quite high. Even
as it stands now, however, early problems assocated with low-level distortion
in transistor amplifiers have been largely solved, with only an exception here
and there.
-
*Consulting Engineer
26
Crossover "notch" distortion, on the
other hand, has nothing to do with output power level, as often assumed.
"Primary crossover" distortion (see Fig.
2.) is due to using Class -B operation,
where signal current is not flowing during a portion of each half cycle in the
power output stage. In effect, there's a
time lag between the period when one
transistor is "on" and another in a
push-pull circuit is "off." This can be
corrected by increasing bias current so
that the "on" transistor time is longer
than the "off" transistor time, thereby
minimizing any discontinuity in signal.
What many people fail to realize,
however, is that there is another type
secondary
of crossover distortion
crossover distortion! And this one still
plagues solid-state power amplifiers.
Whereas primary crossover distortion is the result of a loss of signal during a time period, secondary crossover
distortion or notch distortion has nothing to do with the absence of signal.
Rather, it is the result of inherent transistor switching deficiencies that cause
switching transients to occur. Let us
first examine the nature of this secondary distortion, and then examine a
few modern output circuits to learn
how some manufacturers have taken
different approaches to alleviate the
problem. (Some efforts to reduce it
have been fairly successful, but none
has been fully successful.)
-
"Notch" Distortion
If a close examination is made of
Lissajous distortion patterns produced
by a solid-state power amplifier, one
will observe that there are only two
spikes in the waveform when "primary" crossover distortion exists. In contrast, secondary crossover distortion or
"notch" distortion usually exhibits four
spikes in the waveform, two of which
are generally subdued ones. And whereas the spikes in primary crossover distortion are in the center of the waveform display, the notches of secondary
crossover distortion are decidedly away
from the 'scope display's center.
The drawing in Fig. 3A shows a normal complementary emitter-follower
output, drawn this way for simplicity.
Figure 3B reveals what the circuit
really consists of because of the inherent capacitance inside the transistors.
Since crossover distortion is a frequency -selective phenomenon, becoming greater as frequency is increased,
it must be caused by some reactive action. Also note that, in Fig. 3C, resistors
have been added in the emitter circuits
to stabilize the bias. If there is any inductance at all in these resistors, it will
make the crossover notches worse.
Crossover distortion occurs here because capacitors C1 through C4 charge
up and discharge during alternate half
Fig. 1-Typical low-level transfer distortion is shown in (A), while (B) illustrates the beta
dropout at low current of some transistor devices. The poorest of the lot, 2N3055 output
types, has been widely used by many manufacturers.
160mW
o.1
©
N
10 W
100
80
SD T 8112
PLANAR
Q 60
I-
w
m
40
2N3055
20
0
.001
.01
.1
10
1
COLLECTOR CURRENT
AUDIO
MAY 1969
cycles of the signal. As the frequency
is increased, they are charged up more
and more because of the nature of the
capacitive effect. When the drive signal
alternates on half cycles, these capacitors do not discharge immediately because they are already charged in the
reverse direction. Upon the drive sig-
nal changing polarity, the transistor
cannot turn on immediately because
the reverse charge holds it off for an
instant. The same thing happens on
turn-off, but the effect is less noticeable because the maximum charge on
C2 or C3 is limited to the BV. emitterbase junctions of the output transistors. But C1 and C4 can charge to the
full value of the power supply because
one end is grounded through the supply. Also, the inherent charge -storage
time of the transistors adds to the dilemma being the real culprit in producing the huge turn-off notch.
It is almost impossible to remove
these switching transients from a Class
B output stage. Also the problem can -
Fig.
2 -Primary
crossover distortion.
not be solved by using high -frequency
power transistors as they still have inherent capacitances and storage times,
and as stated earlier, crossover distortion is not a function of bandwidth.
According to the previous statements,- a discrepancy might exist in the
fact that the transistor is supposed to
be a perfect switch (excluding power
yars that are at the present time incredibly high priced). Any engineer
knows that every transistor, even the
fastest, has finite delay and storage
times which bears out the capacitive
effect. So, therefore, transistors are not
perfect switches.
Turning to Fig. 4, we see the waveform of the upper transistor of Fig. 3.
This waveform is a current waveform
(not voltage) and is represented by the
heavy line. The lower transistor is represented by the dotted line. A close-up
examination of the circled portions is
shown in Fig. 5, in which (B) represents turn -on and (A) represents turnoff. One will immediately notice that
the turn-off spike is much larger than
the turn -on spike, bearing out some of
the previous statements. These drawings are of the output stage biased past
the zero-axis, which would represent
Class AB, or at low levels, Class A. Fig.
AUDIO
Fig. 3-(A) Emitter -follower output. (B) Invisible stray capacitances.
(C) With bias -stabilizing resistors.
ure 6 shows what happens when the
bias is increased further. In all cases
the. drawings are greatly exaggerated
to show the effect. Obviously, if the
bias is increased enough we will eventually reach pure Class A operation.
This would be greatly inefficient, however, but I don't doubt that somone has
done this in the belief that it is the
only solution to the problem.
It would be interesting to examine
some of the commercially available
products in order to see what is being
done to solve the problems. The first,
and by far the most popular-for economical reasons-is the old Lin circuit,
or by its more familiar name, the
Quasi -complementary output. This is
shown at (A) in Fig. 7 with the inherent capacitances shown dotted. The
Fig 4-Current waveform of Ql in Fig. 3.
Note turn-off (A) and turn -on (B) notches
greatly exaggerated.
5-Magnified
(A) Turn-off notch and
Turn -on notch.
Fig. 6 -The effect of increasing the bias
(greatly exaggerated).
Fig.
(B)
crossover distortion produced by this
type of output stage is shown at (B).
The large notches are caused by turnoff and the small ones by turn -on. If
the bias is further increased, the large
notches will diminish and move further
towards the outside of the display,
while the small notches will disappear.
As the bias is reduced, the large
notches increase and move towards the
center of the display and will eventually turn into primary crossover distortion. This action may not be evident
in all cases since the amount of power
delivered through the base-emitter
junction may vary greatly depending
on the size of the transistor chip itself.
In other words, in low -power output
stages where only a single emitter -follower output is used, there may be no
or little secondary crossover distortion
even as the bias is increased. I have
noticed this effect as the primary crossover distortion disappeared when the
bias was increased, but there was not
much ensuing secondary crossover distortion. I attributed this only to the
limited number of large junctions in
the output stage.
If one examines the Lissajous pattern, the second -harmonic content is
obvious in the figure -8 pattern. But the
notches can range anywhere from five
to ten times or more the height of the
second harmonic. At 20 kHz the second
harmonic is 40 kHz, and the spikes may
reach out to 400 kHz in harmonic content and possibly further than that.
Many people will say that nobody can
hear out to these high frequencies so
why worry about it. Tests show that
they are evident in listening. [An unusual experiment by the author will be
described next month to prove this
claim-Ed.]
Fig. 6
There is also a further problem in
measurement. Unless the analyzer used
is capable of wideband measurements,
at least out to a megahertz or so, the
27
MAY 1969
www.americanradiohistory.com
AmericanRadioHistory.Com
notches will be quite subdued, if present at all. Low-cost kits will almost
never be capable of the required bandwidth, and therefore are not suitable.
All measurements for this article were
made with a Hewlett-Packard 331A distortion analyzer with special filters
which has useful response out to about
4 megahertz, and a 50 -megahertz Fairchild 767H scope. The oscillator used
was a special design which has a residual distortion of around .002 per cent.
Getting back to Fig. 7B, one might
notice a difference in the notch heights
between the large top one and the
smaller bottom one. This is due to the
different transfer characteristics of the
two output -stage halves. The worst one
by far is the top half which contains
the double emitter follower. This occurs because there are two junctions to
switch off, while there is only one junction on the bottom half. Many engineers must have noticed this difference
and have gone to using completely complementary outputs to solve some of
these problems. It would be interesting
to look at a couple of these circuits,
which have both been published before,
although not necessarily explained.
Commercial Output Stages
7-
Fig.
(A) Quasi -complementary output
stage showing strays. (B) Typical distortion
waveform produced by this stage.
The first one is the JBL T -Circuit as
shown in Fig. 8. The output stage consists of three cascaded complementary
Fig. 8-(A) Equivalent of the JBL amplifier circuit. (B) Typical distortion produced (note
very small notches).
28
emitter followers. The circuit is unique
in several respects. What is most unusual about the circuit is that the four
driver transistors, Qi through Q4, never
cutoff at any time. They are always
conducting on both half cycles. Because of R1 and R2, current will always
flow in the same direction. Only the
output devices themselves, Q5 and Q6,
will cutoff on alternate half cycles. But
since the drivers never cutoff there will
be very little charging of the capacitances and hence little crossover distortion. But there will be some, even
though it is small, and some very small
notches at the low frequency of 200 Hz
were noticed. JBL engineers have used
a very cute trick by introducing R3 and
R4, which apart from helping to stabilize the bias under high temperature
conditions, also help to neutralize the
reverse current flow when driving an
elliptical load line.
Before the first of several of these
amplifiers was measured, it was assumed that there would be third -harmonic distortion by its very nature,
simply from viewing the schematic,
rather than second harmonic. It was a
surprise to find that the distortion
products were almost all 3rd harmonic,
and at nearly all frequencies. This assumption was made because there was
a triple transfer function in the output
stage rather than a double or single
transfer function. It was extremely difficult to view the crossover notches
while measuring the JBL, only because
they were below the harmonic content.
How many engineers have assumed
that since the notches are masked by
the harmonic products, they don't
exist?
Another product, using a totally different design approach, is the Marantz
Fifteen which is diagrammed in Fig. 9.
In the Marantz design, diodes D1 and
D2 play an important role in the reduction of crossover distortion. The approach can be understood better if we
view the transfer characteristics as
shown at (A) and (B) in Fig. 10. Figure
l0A shows the transfer characteristic
without diodes D1 and D2. The switching characteristics are very sharp and
abrupt, and the distortion waveform is
shown at (B). Figure 10C shows what
happens to the transfer function when
diodes DI and D2 are added, making
the necessary bias adjustments. Due to
the tremendous capacitances of the
power diodes in the forward direction
at high frequencies, the transfer function becomes very smooth, much like a
triode rather than a pentode. The crossover notches are much lower than the
inherent harmonic distortion. This
AUDIO
MAY 1969
IF THE CROWN CX822 IS JUST
ANOTHER TAPE RECORDER
- the Stradivarius is just another violin
The Crown CX822 has been opening eyes in testing
labs all over America. In early 1968, Audio magazine
put it to the test, and published its findings in the
April Equipment Report. Following are a few excerpts
=
-
"The Crown CX822
.
.
_
simple."
_ "Editing facilities delightfully
great."
=
"Tape threading is
serviceman's dream, considering the
masters, the sound produced through the Crown CX822
was peerless. When recording and playing back from
records and FM broadcasts, there was absolutely no
aural difference between the original and the copy at
15 ips. The same held true at 71/2 ips, though theory
says, there should have been."
is probably the finest tape
recorder that has been reviewed in these pages. In
addition to delivering phenomenal performance, it
incorporates numerous features and refinements that
place this machine in a class by itself."
.
a
"Playing back first -generation transfers from original
from that report:
_
=
"The CX822 is
unit's inherent complexity."
Construction appears to be rugged enough to withstand parachute drops."
are
"The new Crown CX822 is capable of providing the
most faithful reproduction of sound through the magnetic recording medium that we have observed to date.
And it does it in as foolproof and as easy a way
as we've seen."
"We found the tape motion command system to be as
foolproof as Crown says it is, and could not beat the
computer by design or by accident."
=I11.47"Rdirrir
5 h Stradivarius
of the
sape `Jndusfry
=
-
To receive your copy of
the 4 -page Audio test
report, check the reader
service card, or write:
International
=
Box 1000, Dept. A-5
Elkhart, Indiana 46514
Check No. 29 on Reader Service Card
AUDIO
MAY 1969
29
smooth symmetry is also achieved because all the output current and all the
output voltage is referenced back to the
input inside the bias loop. Notice that
I said bias loop and not feedback loop.
There is also a further difference in
the Marantz amplifier which is unlike
all other units encountered. The output stage is current driven rather than
voltage driven as in the JBL and Lin
circuits. This is beneficial in the sense
that a current drive must be symmetrical at high currents, where a voltage
drive becomes very nonlinear. This is
offset in the JBL circuit by using a
triple emitter follower which greatly
increases the power gain. However,
driving an output stage is not the subject of this article. But it should be
assumed that all the distortion should
come from the output stage of an amplifier, although this may not be true in
all cases.
Next month, modified versions of the
above amplifiers, plus others, are employed in a listening experiment. Æ
0.47
10 mA.
i
+DRIVE
200
mA.
-DRIVE
0.47
Fig. 9-Equivalent of the
output stage of
the Marantz Fifteen amplifier.
Fig. 10-(A) Transfer function, and (B) distortion pattern of the amplifier of Fig. 9
without diodes D1 and D2, and the transfer function (C), and distortion pattern
(D) of the amplifier of Fig. 9 with diodes
Di and D2.
D2%
47-
V
A BZs
of FM
LEONARD FELDMAN
"Front-end" Alignment
ALIGNMENT OF THE r.f. sections of an
FM tuner or receiver is surprisingly
similar to the methods used for AM
radio alignment. Most r.f. tuned circuits are single-tuned (or single
peaked) which requires that they
simply be tuned for maximum output.
This makes r.f. adjustment actually
simpler in many respects than i.f. adjustment. R.f. alignment should never
be attempted unless the i.f. system is
known to be in perfect alignment. In
addition, if an AFC circuit is present
in the tuner or receiver, it should be
defeated or deactivated before r.f.
alignment is undertaken.
In most cases, alignment of the r.f.
section will include making certain
that the receiver, after alignment,
meets its published specifications, particularly with regard to "quieting sensitivity," or IHF "least usable sensitivity." For this reason, it new becomes
imperative that the exact number of
microvolts reaching the antenna term-nals of the receiver under test be
known. With today's ultra-sensitive
tuners and receivers, this means that
the r.f. generator used must be capable
of attenuation down to a fraction of a
microvolt. Furthermore, when the generator output is reduced to its minimum, there must be no "leakage" or
radiation of r.f. from the transmission
cable, the generator metal housing or
even the a.c. power cord. These shielding requirements are part of what
makes good FM generators so expen-
sive.
Manufacturers involved in the design and production of FM receiving
equipment often test their products in
a magnetically and electrostatically
shielded room, often called a "screen
room," since tightly woven copper
screening is usually used to cover
walls, ceiling, and floor, as well as any
doorways leading into the room. The
use of such a shielded room prevents
broadcast signals from nearby stations
from interfering with the alignment
and test process. The IHF standard for
tuner measurement (and alignment)
requires that tests be made at three
frequencies: 90 MHz, 98 MHz, and
106 MHz. Since there may well be stations within 100 kHz of all of these f re30
quencies, it is important to block out
reception of these stations and deal
only with the r.f. produced by the signal generator.
As mentioned previously, the coaxial cable should connect r.f. energy
to the antenna terminals by means of
a matching network. Most generators
have an internal "output impedance"
of 50 ohms, while most FM tuners have
input impedance of either 75 ohms or,
more popularly, 300 ohms. In the case
of a balanced 300 -ohm system (the
most popular type), the network shown
in Fig 1 should be used to provide a
proper match between generator and
receiver or tuner. Since a voltage drop
will take place across the series resistors, however, the actual number of
microvolts reaching the tuner or receiver antenna terminals will be half
the number of microvolts read on the
calibrated dial of the generator.
Test points for connecting a VTVM
or an oscilloscope are the same as those
used for i.f. alignment, since the i.f.
system, having been previously aligned,
TUNER
GENERATOR
1200
t
-+-
-gen.
=
50St
3002
b
o
o
á
CO
1201-2
1-Matching network required for
connecting 50 -ohm generator to 300 -ohm
balanced antenna input on FM tuner.
Dotted connection may be omitted with
practically no increase in mismatch.
Fig.
is now being used as a fixed amplifier.
If using a meter as the indicator, the
steps to be followed are these:
1. Set the tuner dial to 106 MHz and
set the FM signal generator to the
same frequency.
2. Adjust the oscillator section trimmer capacitor for a peak indication,
rocking the trimmer adjustment back
and forth a couple of times to make
sure absolute peak has been achieved.
Always work with the least amount of
r.f. signal consistent with on -scale
meter readings, using the lowest available scale of the VTVM.
3. Adjust trimmers of all r.f. sections
of the variable capacitors for a peak indication. The number of trimmers will
depend upon the number of tuned sections there are in the r.f. section of the
set under test.
4. Repeat all adjustments, at a lower
signal level, if possible. In many circuits, adjustment of one trimmer may
affect adjustment of others, and so the
final adjustment points should be
"zeroed in" by repeated adjustmentsincluding even the local oscillator
trimmer.
(Continued on page 62)
AUDIO
MAY 1969
Martin Audio announces
the first professional stereo mixer
with built in echo mixing facilities
SONOMIX 602E
Sonomix 602 is the newest member of our mixer
family. It incorporates all the features of the
Sonomix 601 mono six microphone or line inputs,
AC or accessory ni -cad battery pack
plus dual
stereo outputs with each mixing pot switchable to
left, center or right channel. Each input has its own
echo pot, which mixes to a mono echo send to
drive an external echo chamber. The echo signal is
fed to left and right echo return pots, and mixed
with the channel outputs.
95DB Gain 200 Microphone Inputs 100 kst Line Inputs
-
-
SZ
+4 VU
60052 Stereo
Outputs
XLR Connectors on MIC Inputs and Line
Outputs
Model 602E with echo mixing and desk top cabinet $1005
Model 602E without cabinet for rack mounting
$ 945
Model 602 without echo mixing for rack mounting $ 795
MARTIN AUDIO CORP.
320 WEST 46th STREET/ NEW YORK, NEW YORK 10036/212-661-6987
BE SURE
AUDIO
MAY 1969
TO VISIT US AT BOOTH 41, A.E.S SHOW, HOLLYWOOD ROOSEVELT HOTEL, LOS ANGELES, CALIF., APRIL 28 -MAY
Check No. 31 on Reader Service Card
-
www.americanradiohistory.com
AmericanRadioHistory.Com
1.
31
A comparison of the performance of
VU and peak reading meters
Richard D. M. Negus, Capitol Records,
Inc.
C3
AUDIO ENGINEERING SOCIETY
PROGRAM
Tiírty-síti ConventIon
and *x1iíbítíon
of
?rof essíonal ?roducts
April 28 -May 1, 1969
HOLLYWOOD ROOSEVELT HOTEL
7000 Hollywood Boulevard, Hollywood, Calif.
REGISTRATION: Mezzanine, 9:30 AM -8:00 PM
EXHIBITS: Monday and Tuesday: 1:00 PM -9:00 PM
Wednesday and Thursday: 1:00 PM -5:00 PM
THE TECHNICAL PAPERS
For readers unable to attend, many of
these papers can be had in preprint form
(50e ea., AES members; 85e ea. non-members) from Audio Engineering Society,
Inc., Room 248, The Lincoln Building, 60
E. 42nd St, New York N. Y. 10017. Write
A new user -oriented professional unidirectional microphone
B1
Robert B. Schulein, Shure Brothers, Inc.
B2 A new underwater earphone
Louis A. Abbagnaro and Benjamin B.
Bauer, CBS Laboratories
B3
for list of available titles.
Loudspeaker phase characteristics
Richard C. Heyser, Cal. Tech. Jet Propulsion Laboratory
The meaning of quantitative loudspeaker measurements
Charles McShane, Acoustic Research,
Inc.
B4
Monday, April 28:
(10:00 a.m.)
AMPLIFIER AND
AUDIO CIRCUITS
Chairman: Paul Spranger, Altec Lansing
Al
Design considerations of low -noise
B5
Design parameters of a dual woofer
speaker system
Edward M. Long, Ampex Corp.
B6
An improved theatre -type loudspeak-
audio input circuitry
A. Douglas Smith, Shure Brothers, Inc.
A2 Transmission lines in studios
O. Everett Wiedmann, LTV Research
Center
A3 An unusually flexible OP amp mixing console
Lyle Fain, Fedco Audio Labs
B7
Bridging the audio limiter gap
J. Noble and Robert James Bird,
Altec Lansing
A5 Automatic presence equalizer
Richard G. Allen, Emil L. Torick and
Benjamin B. Bauer, CBS Laboratories
A6 Low -noise
replay -preamplifier for
professional audio recorder
Zoltan Vajda, University of Minnesota
(8:00 p.m.)
A4
James
(1:30 p.m.)
Chairman:
Center
32
B.
er system
John K. Hilliard, LTV Research Center
developments in high -frequency drivers and horns for auditorium
sound reinforcement
William L. Hayes, Altec Lansing
R.
AUDIO SYSTEMS
Chairman: Jack Purcell, Purcell & Noppe &
Associates, Inc.
ACOUSTICS AND HEARING
Chairman: Mark B. Gardner, Bell Telephone Laboratories, Inc.
An experimental sound system for
the Hollywood Bowl used in 1936
Arthur R. Soffel, LTV Research Center
D1
D2 Talking and listening levels in verbal
communication-Importance of specifying
parametric values
Mark G. Gardner, Bell Telephone Labo-
ratories, Inc.
Sound reproduction in the home
Harry F. Olson, RCA Laboratories
D4 Acoustics of multipurpose auditoriums
Vern O. Knudsen, University of California at Los Angeles
D3
The ear as an instrument for determining the quality of musical tones
Harvey Fletcher, Brigham Young University
D5
(1:30 p.m.)
MUSIC AND SPEECH
Chairman: James Campbell, University of
California
A directional communications receiver for underwater swimmers
Guy V. Love, Emil L. Torick, Benjamin
B. Bauer, CBS Laboratories
A recording console for the needs of
Robert A. Bushnell & J. Jerrold Ferree,
Bushnell Electronics Corp., Van Nuys,
California and United Recording Corp.
New music buildings-the sonic en-
El
vironment
Gerald Strang, California State College
at Long Beach, Department of Music
E2
Loudness meter
A. Hackley, H.
F. Olson and D.
McCoy, RCA Laboratories
R.
S.
Some recent developments in computer -generated tone qualities
J. C. Risset, Bell Telephone Laboratories,
E3
Inc.
A music department,
1966; Died:
E4
born:
1
July
of
L.
Campbell, Department
Music, University of California
James
Cl
tomorrow
Beavers, LTV Research
Vaneklasen & Associates
Tuesday, April 29:
(9:30 a.m.)
Recent
Held at A&M Studios, Sunset Blvd. & La
Brea, Hollywood, Calif.
C2
TRANSDUCERS
F.
Loudspeaker voice coils
John King, Cleveland Electrónics
B8
A description and tour of the new
A&M studios
Howard Holzer, HAECO, Larry Levine,
A&M Records, and Jerry Christoff, Paul
C4
(7:30 p.m.)
NOISE
Chairman: Karl S. Pearsons, Bolt Beranek
and Newman, Inc.
F1
Transportation noise source
Richard C. Potter, Wyle Laboratories
Check No. 33 on Reader Service Card
---
The best your money can buy. Period!
Lightweight. A full 7 -inch reel capacity professional studio tape deck. Pick it up and take it
anywhere. Operates on a self -enclosed rechargeable nickel -cadmium battery pack-or
plugged into AC.
11
Four Heads. The 770-2 has
two -track erase, record, and
playback heads plus a four -
track playback head. The
770-4 has four -track erase,
record, and playback heads
plus a two -track playback
head.
Better -than -Studio Specs.
Frequency response: 20
Hz to 22 KHz, 40 Hz to
18 KHz ±2 [email protected]/zips.
S -N ratio at peak level
to unweighted noise:
(Model 770-2) 58 dB
ServoControl Motor with
VariSpeed Tuning. Auto-
or better; (Model
matically maintains
exact speed during
mechanical load
770-4) 56 dB or better. Wow and flut-
ter: less than
0.09%
@
changes and voltage
71/, less
variations. Built-in
VariSpeed tuning
than 0.12% @
33/4, less than
0.2% @ 17/e.
permits vernier adjustment of plus or
minus 7% of any of
the three speeds.
Ideal for pitch tuning to any musical
instrument.
Exclusive Sony
Noise -Reduction
System. Sony "SNR"
automatically reduces
gain of playback
amplifier by 6 dB
during very low
passages, when background noise is
most predominant. Noise level is
greatly reduced, dynamic range expanded 100%. Also incorporated is a
built-in limiter to automatically control overload distortion. Both "SNR"
and limiter are switch defeatable.
'1969. SUPERSCOPE. INC.
71/2, 3314, 1z/8 ips. Other
features include two professionally -
Three Speeds.
calibrated VU meters, built-in
line -and -mike mixing, push-button
operation, scrape flutter filter, lowimpedance Cannon plug mike inputs, tape/source monitoring.
Sony Model 770. Priced at $750. For
a free copy of our latest tape recorder
catalog, write to Mr. Phillips, Sony/
Superscope, Inc., 8142 Vineland Avenue, Sun Valley, California 91352.
SONY
You never heard it so good.
Monday, 7:30 p.m.-Cont'd.
tion
NOISE
Klauss
Inc.
Plumbing noise control
Ronald McKay, Bolt Beranek and Newman, Inc.
H3
Updating and interpreting the speech
interference level (SIL)
John C. Webster, U.S. Navy Electronics
Laboratory
H4
F2
F3
Human phase sensitivity to impulse
F4
signals
Sanford Fidel!, Bolt Beranek and Newman, Inc.
Procedures for evaluating damage risk
from exposure to noise
F5
Kari D. Kryter, Stanford Research Insti-
tute
F6
Magnetic tape testing and interpreta-
H2
Evaluation of ear protection devices
John E. Parnell, PNP Associates
E.
Naumann, BASF Computron,
The measurement of medium -wavelength flux on a magnetic tape record
John G. McKnight, Ampex C & E Products Div.
A simplified -hysteresis -loop model of
the AC biased magnetic recording process
Zoltan Vajda, University of Minnesota
An examination of dropouts occurring in the magnetic recording and reproduction process
William Van Keuren, Jet Propulsion Laboratories
H6 Design improvements applied to the
Fairbanks time -alteration device for recorded sound and uses of the time -alteration technique
Wayne Graham, Discerned Sound
H5
Reliability in production testing of
loudspeaker components and systems
Donald S. Schroeder and Edward M.
Long, Ampex Córporation, Elk Grove
Village, Illinois
K1
Automated frequency -response measurement
Allen E. Byers, United Recording Electronics Industries
K2
Crosstalk meaurements on magnetic
recording heads
Robert E. Barbour, Nortronics Co., Inc.
K3
`1
Real-time spectrum analysis
David Rose, Hewlett-Packard
K4
Real-time spectrum analysis as a tool
in Acousta-Voicing
Don Davis, Altec Lansing
K5
The seven deadly sins of instrumen-
K6
tation
E.
John Wootten, B&K Instruments, Inc.
Instrumentation techniques used for
performance evaluation of hearing aids
Erwin Weiss, Beltone Electronics Corp.
K7
Wednesday, April 30:
Thursday, May 1:
(9:30 a.m.)
(9:30 a.m.)
SIGNAL PROCESSING
DISC RECORDING
Chairman:
Chairman: Frank
E.
Pontius, Westrex
A tape -to-disc mastering system featuring unique control and monitoring
facilities
improved solid-state
driving system for the Westrex 3D and
Microphone
J1
and
J2
HAECO SC-1 stereo cutterheads
Howard S. Holzer, HAECO
The first all solid-state stereo recording package for disc recordings
Stephen F. Temmer, Gotham Audio
Corp.
J3
Performance characteristics of the
commercial stereo disc
G4
Inc.
Jaffe & Associates, Inc.
Equalization/Filtering
Lawrence Levine, A&M Records; 2. H.
Philip lehle, Atlantic Records; 3. John P.
Jarvis, Universal Audio Division of UREI
Compression/Limiting
1. Richard Welch, Bonneville International; 2. DeWitt F. Morris, United Recording Division of UREI; 3. Charles F.
Swisher, Christopher Jaffe & Associates,
Inc.
John M. Eargle, RCA Record Div.
J4
G5
Reverberation/Echo
Western Records Division
of UREI; 2. Richard Stumpf, Universal
Studios; 3. Stephen F. Temmer, Gotham
Audio Corp.
1. John Neal,
B.
Automatic record pressing
William S. Bachman, Columbia Records
G6
J5
Tape machine
Thomas Hidley, T. T. G., Inc.; 2. Hamilton Brosious, Scully Recording Instruments Corp.; 3. C. Dale Manquen, 3M
Company; 4. Leon A. Wortman, Ampex
Chairman: Charles
TAPE RECORDING
Chairman: Keith O. Johnson, Gauss Electrophysics, Inc.
A simple tailoring machine for Philips
cassettes
James B. Wood, General Recorded Tape,
Inc.
H1
Corp.
Chairman: Bernard Katz, B&K Instruments,
Inc.
Swisher, Christopher
A sound reinforcement system for
multiple conference rooms
Melvin S. Draper, The Boeing Company Space Div.
Location of loudspeakers in sound reinforcement systems
Don Davis, Altec Lansing
L2
L3 A new music and sound -effects system for theatrical productions
Dan Dugan, American Conservatory
Theatre
L4 Comparison of room-loudspeaker response in well-behaved reverberant rooms
to the response in an anechoic environ-
ment
James Long and
tro -Voice, Inc.
William Raventos, Elec-
Design innovations in a modern portable sound reinforcement system
L5
Stephen W. Desper, Beach Boy Entertainment Enterprises, and Robert L. Bennett, Quad -Eight Sound Corporation
(1:30 p.m.)
INSTRUMENTATION
F.
11
1.
(1:30 p.m.)
L
SOUND REINFORCEMENT
1.
G3
SESSION
(7:30 p.m.)
David Ronne, Metromedia Producers
Corp.; 2. Thomas May, Columbia Records; 3. L R. Burroughs, Electro -Voice,
1.
Engineering
The dynamic range of disc records
Daniel W. Gravereaux and Benjamin
Bauer, CBS Laboratories
Dilley, Spectra
A series of five separate panel discussions,
followed by audience/panel participation.
Jack K. Williams, Pacific Recorders and
A new
G.
Sonics
G1
G2
William
On the objective testing of circumaural hearing protectors
R. H. Campbell, David Clark Company,
Inc.
K8
L6
Sound amplification system for the
Diego All American stadium
Wilfred A. Malmlund and David L. Klepper, Bolt Beranek and Newman, Inc.
San
AUDIO
34
www.americanradiohistory.com
AmericanRadioHistory.Com
MAY 1969
OUR NEWEST STEREO TUNER
The stereo FM -3 was introduced in 1963 and
we are still barely able to keep up with the
demand. After six years, it remains the most
popular of all stereo tuners.
Our newest stereo tuner doesn't replace the
original mono FM -1, which after nine years still
outsells all other mono tuners combined.
This unprecedented longevity is explained
by Dynaco's unswerving devotion to performance, reliability and unmatched low cost. The
stereo FM -3 is only $99.95 as a kit and
$154.95 factory assembled. The $79.95 mono
FM -1 can be converted to stereo at any time
by adding the $29.95 FMX-3 multiplex module.
Dynaco introduces new products only when
they fill a real need. They never render previous models obsolete. And at less than half
the cost of other tuners, such consummate
value just naturally gets around.
We can't promise that the FM -3 will still be
our newest tuner in 1979.
But we do know it won't be out of date.
DYNACO, INC., 3060 JEFFERSON ST., PHILA., PA. 19121
AUDIO
MAY
1969
35
The Product
Sampler
The following sampling of the new
and interesting equipment to be shown
at the 36th AES Convention and Exhibit illustrates some of the professional gear that serves to keep up the
high standards of the audio profession.
Abphot Corp. will introduce its new
Model 1302 Audio Analyzer, intended
for general-purpose audio measurements where a balanced signal source
is not required. The frequency range
has been extended from 120 Hz to 1.2
MHz for the generator, and from 1 to
3 MHz for the voltmeter. Also built-in
is a tracking distortion meter with a
sensitivity of 100 mV set level and
0.3% THD full-scale reading, and a direct -reading phase -angle measurement
between send and receive signals. Highpass and low-pass filters are also included, and the meter sensitivity extends down to -80 dBm. The unit is
flat within ±0.2 dB over the entire
operating range.
Check No.
21
on Reader Service Card
AKG Div., North American Philips
Corp. will show two new microphones
-the D -190E cardioid dynamic with a
user net of $50.00, and the D -900E dynamic "shotgun" model with a user net
of $149.00. The latter is 261/8" long and
exhibits a 20 -dB rejection at the sides
and back throughout the entire frequency range. It is equipped with a
two -position bass rolloff switch providing cuts of 7 and 20 dB respectively at
30 Hz. The D -190E offers a typical
cardioid pattern, with rejection at the
rear of 18 dB at 1000 Hz, and the cardioid characteristic is maintained over
the entire frequency range.
Check No. 22 on Reader Service Card
Altec Lansing will unveil a number of
new products for the broadcast and recording industries, including the Model
9300 broadcast console of modular
plug-in design capable of up to 28 input and 24 output channels. Input
modules will include preamps, with
echo and cue facilities, and a new type
of volume indicating device employing
light instead of VU meters is introduced. In addition, the famous 9200A
and 250T-3 consoles will be on display,
together with a new 100 -watt solid-state
amplifier, Model 9477A. The Model
9473A solid-state limiter amplifier, designed around the concept of spectral
separation, which eliminates envelope
Oc;
Altec 9477A
100-W Amplifier
Electro -Voice
Microphone
Type 2006
Heterodyne Voltmeter
B & K
RE -20
distortion caused by too short a release
time will also be shown, as will the
new Senior Monitor/Playback Speakers System, Model 9845.
Check No. 24 on Reader Service Card
Audio Designs
& Mfg. Inc.
will show
their Audex switching modules in three
-
versions Audex I, which will separately switch a program source to 16
program busses and 4 echo busses, preventing selection of more than one buss
at a time, and cancelling the previously
AES Exhibitors
Manufacturer
Abphot Corp.
Booth No.
18
AKG-Div. of North American Philips
1
Corp.
9/10/11
Altec Lansing
Room C
Ampex Corp.
Audio Designs & Manufacturing, Inc..... 45
Mezzanine
Automated Processes, Inc.
12/13
B & K Instruments, Inc.
Mezzanine
Creatronics, Inc.
Rooms H &
Dolby Laboratories, Inc.
17
Electrodyne Corp.
Mezzanine
Electro -Sound
Boulevard Room
Electro-Voice, Inc.
Fairchild Recording Equipment Corp..... 2
43
Gately Electronics
7/8
Gauss Electrophysics, Inc.
21/22
Gotham Audio Corp.
Room F
Harman-Kardon, Inc.
38
Harvey Radio Co., Inc.
39/40
Hewlett-Packard Co.
25
Holzer Audio Engineering Corp.
33/34
1BL-lames B. Lansing Sound, Inc.
Langevin, Div. of Scientific Industries, Inc. 5
16
Lipps, Inc.
35/36/37
3M Company
24
Magnetic Recorders, Co.
41
Martin Audio Corp.
32
McMartin Industries, Inc.
29/30
Melcor Electronics Corp.
15
Metrotech, Inc.
Room E
R. A. Moog, Inc.
47
Nagra Magnetic Recorders, Inc.
44
Nortronics Company, Inc.
Parasound, Inc.
Suite 1106/07
Orban Associatates
14
Quad -Eight Sound Corp.
Scully Recording Instruments Co. ...26/27/28
3
Sennheiser Electronics Corp. (N.Y.)
4
Shure Brothers, Inc.
23
Spectra Sonics
45
Stanton Magnetics, Inc.
31
Superscope, Inc.
Taber Manufacturing and Engineering Co. 6
42
Tandberg of America, Inc.
United Recording Electronic Industries:
20
Universal Audio
20A
Waveforms
19
Wiegand Audio Laboratories
I
selected buss when a new one is selected on the switcher control. Audex
II will cumulatively switch a source to
any one or all 16 program busses and
4 echo busses, and Audex II, which
solves the problem of matrixing in multichannel consoles, since it will accept
20 input sources and combine them to
a single output. Channel indication is
shown by computer -type digital readout on the face of each module, all of
which switch noiselessly with a switching life in excess of 10 million operations.
Check No. 26 on Reader Service Card
B & K Instruments, Inc. will display a
new Spectrum Shaper, Model 124,
especially designed for the audio market, along with its Model 123 which has
been shown heretofore. And in addition
to a wide range of sound level meters,
including an impulse type, they will
show the Model 2006 Heterodyne Voltmeter, which is ideal for measurements
in the r.f. and v.h.f. ranges. It is portable, light in weight, and battery operated to provide maximum flexibility
in use. It will measure the amplitude
of high -frequency signals and determine their frequency as well as the
percentage modulation. The voltmeter
covers the range from 40 kHz to 230
MHz, and has a sensitivity ranging
from 2 /IV to 50 V, with bandwidths of
2.5 kHz and 200 kHz.
Check No. 28 on Reader Service Card
Dolby Laboratories, Inc. will show the
KLH recorder as well as Dolby A301
Noise Reduction units and remote
change-over unit (enables 301 to
change to record or playback configuration remotely). New items are custom-made, heavy-duty portable cases
for Dolby equipment. One case is made
for a single Dolby A301 unit; a second
model case is made for the A301, plus
a remote change -over unit. There will
be continuous demonstrations of the
Dolby system.
Check No. 30 on Reader Service Card
Electro -Voice, Inc. will present the
RE20 microphone, a rugged, extremely
AUDIO
36
www.americanradiohistory.com
AmericanRadioHistory.Com
MAY 1969
This little speaker
may cause the
downfall of the
capitalist system.
Until a few months ago, only capitalists
owned high-fidelity systems of really
superior quality. For the ordinary rich
American, the price was simply too high.
Of course, we aren't talking about
those nice middle-class systems for six
or seven hundred dollars, with their
loud and clear but unmistakably canned
sound. We mean the real goods, the
big, professional -type stereo installations in which the two loudspeakers
alone may have cost well over a thousand.
That kind of capitalist system was
economically justified by its performance, until the September Revolution.
Then, at the New York hi-fi show last
September, Rectilinear introduced a
small loudspeaker, called the Mini -III
and priced at $79.50. After hearing it,
even capitalists began to wonder why
anyone should pay more for any
If
that claim strikes you as so much
propaganda, we're not the least bit
worried. The superiority of the Mini -III
isn't so subtle or elusive that you can
possibly fail to recognize it when you
hear it. Its exceptional smoothness, definition, freedom from distortion and lack
of "boxiness" are easily audible characteristics to music lovers.
However, you may not recognize the
full consequences of this revolution. The
downfall of the capitalist system is just
one of them. (Obviously, the same system with the same-or better-sound for
about a thousand dollars less is no
longer exclusively for capitalists.) But
middle-class and even lower-middle-
speaker.
The Rectilinear Mini -III is the brainchild of a group of young, unorthodox,
we might even say radical, engineers.
The kind you'd be more likely to find
working for, say, NASA than for the
hi-fi Establishment. They took great delight in demolishing the Establishment
myth that speaker performance depends
on size and price. And they came up
with enough bright new ideas to make
the 12" by 19" by 191/2" deep, under eighty -dollar Mini -III one of the four
or five best -sounding loudspeakers
available today-regardless of size or
price.
AUDIO
MAY 1969
class systems are also affected.
Suppose, for example, that you've
been thinking of buying one of the
widely advertised stereo compacts. The
better ones cost upwards of $400, complete with their own speakers. Now
consider the alternative:
A pair of Mini -Ill's for $159. One of
the new generation of high-powered
solid-state stereo receivers (they're
great!) for well under $300. One of the
best imported four -speed automatic
turntables with a good magnetic stereo
cartridge, for about $100. Total: just
over $500.
This combination will perform almost
in a class with the world's most expensive systems and about seventeen
classes above the best stereo compacts
-for barely $100 more. Plus about ten
minutes more of your time, to connect
the speakers and plug in the turntable.
Remember, it's capital that we made
superfluous. Not labor.
(For further information, see your
audio dealer or write directly to
the Rectilinear Research Corporation,
30 Main St.,
Brooklyn,
N.Y. 11201.)
by
Check No. 37 on Reader Service Card
Rectilinear
37
MI wen MI 119 Millim!a
roomiuooimuro
Martin Sonomix 602E
Gotham Model OY Speaker System
3M 16 -track, two-inch recorder
wide -range, high -quality cardioid dynamic model. Its ruggedness is assured
by its case which is machined out of
solid -steel bar stock, and the cartridge
is shock mounted and electrically
shielded. A built-in pop filter eliminates any breath or wind noises, and
an external mount including extra
shock protection is available for boom
or stand use. Also to be shown are the
RE16 dynamic cardioid microphone
created for the most exacting professional use. Physically it is much like
the RE15 except for a newly designed
blast filter. In addition, its characteristics are carefully controlled so as to
match performance closely between
two separate microphones of the same
model. The RE11 is a similar microphone, but meets requirements where
there is less need for precise unit -to unit matching. All of these models employ the Acoustalloy® non-metallic
diaphragm which is exclusive with
Electro-Voice. Two monitor speaker
systems, Sentry I and Sentry II, will
also be a feature of the E -V exhibit.
Check No. 32 on Reader Service Card
Gately Electronics will show their entire line of mixers-in both attache case
together with
and console models
their new EM -7 Stereo Echo Mixer
and accessory four -channel equalizer,
EQ-7. The EM -7 mixer handles up to
eight inputs (four line and four mike
inputs) switch selectable from the front
panel, and any mixing or echo -mixing
channel can be switch-assigned to
either output channel or to both simultaneously. These mixers are stackable
to permit increasing the number of input channels to 16, 24, or more, if required. The EQ-7 accessory 4 -channel
equalizer plugs directly into the EM -7
mixer, and allows adding up to 15 dB
of boost or cut at 20 Hz and 20 kHz on
four channels independently and simultaneously. Suitable amplifiers are
included in the EQ-7 to make up
equalization losses.
-
Check No. 34 on Reader Service Card
Gotham Audio Corporation will show
the new Monitor Speaker Model OY,
a wall -mounted loudspeaker system
containing four speakers and two 30 watt amplifiers. The response of the
system is said to be from 40 Hz to 16
kHz ±2 dB. Also to be shown is the
38
ME -102B wow and flutter meter, which
is suitable for laboratgry investigations
and the testing of high -quality recorders. This solid-state instrument includes its own oscillator, and measures
between ±.01 and ±1.0%. In addition,
they will show the Beyer DT-48S
Headphones which have a frequency
response which extends to well below
20 Hz and subjectively to beyond 18
kHz, with distortion below 0.3%, making them especially suitable for highlevel listening. The Newmann FET-80
Series of transistor condenser microphones will be shown. This series permits serving up to 40 mikes through
existing outlets without the necessity
of changing the wiring. This series is
represented by seven different models
of microphones with varying characteristics.
Check No. 36 on Reader Service Card
JBL marks its introduction to the professional monitor speaker field with the
initial models, which include the Model
4310-a compact monitor speaker system with independent adjustment of
presence (1500 to 7000 Hz) and brilliance (5000 to 15,000 Hz), and capable
of handling 35 watts of continuous program power with a smooth frequency
responsible from 40 to 15,000 Hz. Dispersion is greater than 90 deg. in both
planes, allowing either vertical or horizontal mounting.
Check No. 44 on Reader Service Card
Langevin, a Div. of Scientific Industries, will exhibit a completed program
of prewired modules and console housings for nineteen positions. These are
available in any one to four output
channels. Exclusive features are the
new high-level modules that allow 8 to
1 and/or 4 to 1 mix -down, and also
provide multi -track wiring to headphones for selected sync work. Also to
be shown is the first of a line of highpowered monitor and sound reinforcing solid-state amplifiers, the AM100,
which has multiple impedances and low
distortion output, with a variety of input impedances. Overload and shorted output protection is integrated into the
overall design.
Check No. 46 on Reader Service Card
Lipps, Inc. plan to display their latest
version of a 16 -track 2-inch head as-
Nagra IV Portable recorder
sembly for multiple -channel recording.
This assembly is completely pre aligned and contains all necessary
hardware, including scrape -flutter idlers and a precision slide control for
operating tape -lifter arms. The record
head is of Lipps "LXT" design which
provides up to 17 dB crosstalk rejection
and has a flat response past 10,000 Hz
when used for sel -sync playback.
Check No. 48 on Reader Service Card
3M Company will show a compact
2 -inch 16-track professional recorder/
reproducer featuring an integrated
overdub control for remote synchronization of tracks. This model is the latest addition to the line of 3M mastering recorders, which are available in
configurations ranging from 150 -mil to
2 -inch tape widths and two to sixteen
tracks. Also to be shown is a model
which is convertible to either 1 -inch,
eight -track, or 2 -inch, sixteen track
configurations.
Check No. 80 on Reader Service Card
Martin Audio will show the Stereo
Sonomix 602 which offers echo mixing
facilities and the ability to switch any
of its six inputs instantly between line
and microphone. It is available with a
plug-in rechargeable nickel -cadmium
battery pack which permits its use in
settings where a.c. power is inaccessible. The unit exceeds studio requirements, yet is packaged in a compact
20 x 8 x 10 in. housing which makes it
ideal for travel and location use, or for
studios where space is limited.
Check No. 50 on Reader Service Card
Melcor Electronics Corp. will display
a new 100 -watt monitor amplifier fea-
turing automatic dissipation -limiting
circuitry, high -reliability push -pull parallel output, and optional isolated
70 -volt line output transformer. This
model is available in either rack or
shelf mounting. In addition, a new
Channel Programming Switch module
with a built-in pan -pot control will be
shown, as well as additional IMPAC
modules and power supplies.
Check No. 82 on Reader Service Card
Metrotech, Inc., which recently became a division of Dictaphone Corporation, continues to offer the unique
advantage of two -directional record
AUDIO
MAY 1969
Superscope's
Shure Model SE20 Phono Preamp
Sony C-77
Tele -microphone
and reproduce capabilities, together
with front -panel controls for each reel drive motor. These machines are available in any adjacent pair of standard
speeds from 11/2 to 15 ips, with logger
models extending the slow speeds to
0/16, 10/42, and 15/16 ips.
Check No. 53 on Reader Service Card
Nagra Magnetic Recorders, Inc. will fea-
ture the new Nagra 1/4 -in. tape synchronous sound recorder and accessories. The Nagra IV embodies 48 new
features not previously available,
among them a new modular assembly
which makes it possible to include
within the recorder a number of formerly external accessories. Automatic
mixing with a new dual -timer automatic gain control, automatic overload
protection, increased S/N, reduced
distortion, and increased permissible
recording level are among the new
features.
Check No. 54 on Reader Service Card
Quad -Eight Electronics will display a
new Monitor Module for multi -track
consoles which includes a remote -sync
control, stereo mix -down, echo, speaker
matrix, and headphone cue. Also featured is an eight -frequency active
graphic equalizer with 12 dB of boost
and attenuation, available in multichannel models.
Check No. 69 on Reader Service Card
Sennheiser Electronic Corp. will show
their MITEC Synchro-System, distributed solely by Gordon Enterprises of
North Hollywood, Calif. This device,
which is a wireless system, provides the
necessary accessories to connect any
professional film camera that is
equipped for Neo Pilot Tone to the
Nagra tape recorder without connecting cables. The wireless microphone/
transmitter/receiver makes the cameraman independent from the sound
man, and both may move around freely
within the range of the wireless microphone. The unit transmits a pilot sync
signal and the start mark, in addition
to a talkback channel from the cameraman to the sound man, and all these
functions operate simultaneously without interference with each other.
Check No. 70 on Reader Service Card
Shure Brothers, Inc., will
AUDIO
feature the
UREI Model 1100 Power Amplifier
SM60 omnidirectional dynamic microphone which is a slim, neat -appearing
model which is also rugged and versatile. It is designed for professional applications, and is equipped with a builtin wind and pop filter. In addition, they
will show their M67 professional microphone mixer specifically designed
for studio, remote, or original sound
reinforcement use, or as an add-on
mixer for expanding existing facilities.
Also to be featured is the SE20 two-
channel solid-state equalized preamp/
line amplifier designed to provide the
highest quality disc reproduction for
broadcast and recording studio use. Its
high -impedance inputs properly match
almost all magnetic disc reproducers,
and it is provided with individual high and low -frequency equalization trimmers on each channel.
Check No. 56 on Reader Service Card
Spectra-Sonics will feature its Model
500 program equalizer, a miniature de-
vice employing an active feedback element which will provide boosts and
cuts of up to 12 dB in 2-dB steps at
any of four high frequencies and any
of four low frequencies simultaneously. Measuring only 11/2" wide, 31/2"
high, and 21/4" deep, the equalizer has
an insertion loss of zero, and can be
attached to panel holes by the nuts on
the switch controls. Among other products to be displayed are: amplifiers,
equalizers and filters, and console support equipment.
Check No. 64 on Reader Service Card
Stanton Magnetics will show their
Models 500A, 500AA and 500E broadcast standard series, as well as the
Model 681 Calibration Standard. The
500's are equipped with conical styli in
either 0.7 or 0.5 -mil radii, while the
500E is fitted with an elliptical stylus
with radii of 0.4 and 0.9 mils. All
models are flat from 20 to 10,000 Hz
±1 dB, and from 10 to 20,000 Hz ±2
dB, and interchangeable styli make it
possible to adapt the cartridge for the
most exacting applications.
Check No. 71 on Reader Service Card
Superscope, Inc., will feature the Sony
Model 770 seven-inch portable stereo
tape recorder (see profile on page 40),
along with their latest in miniaturiza-
tion-the
C-115 "Electret" FET con -
Wiegand 8-track Mixing Console
denser microphone which weighs less
than a quarter of an ounce and can be
worn as a tie tack. In one form-the
C-116-the microphone is uniquely
equipped with a telescoping rod for better accessibility to the sound source,
yet when closed measures only 0.515"
by 8.66" and weighs 2 oz. The electret
microphone has a diaphragm made of a
special plastic film which can be
"charged" to provide the polarizing potential for the condenser transducer.
The C-77 condenser Tele -microphone,
new to the line, is said to be the most
highly directional and sensitive microphone in the world. It features a
cigarette -pack size booster/headset
monitoring pack with a 6-, 12-, or 18 -dB
gain factor.
Check No. 57 on Reader Service Card
United Recording Electronics Industries will exhibit a highly flexible, 20 input, 12 -output recording console con-
taining almost all products of UREI's
Universal Audio product line, and
which was custom-built for a major
Los Angeles studio. They will also
show two additional versions of Model
1100 LU, a 75 -watt studio monitor am-
plifier-the
1100 LV, which will have
the same features as the LU, plus an
output transformer, and the 1100 JV,
which features an output transformer
but which does not have the equalizer
section of the 1100 L series. Also to be
shown will be a compressor/limiter option for UREI's Model 2100 S Input
Module, which will be available either
factory installed or for field modification.
Check No. 72 on Reader Service Card
Wiegand Audio Laboratories will be
displaying their new model 1408083
Eight -Track Mixing Console, which is
really two consoles in one. It is a 14input, 8-track console, plus an 8-input,
three -track remix console. It incorporates such built-in features as self-contained reverb on all eleven output
channels, special-effects switching with
graphic equalizer, slating, talk -back,
cueing, and test -tone facilities, together
with four 120 -watt solid-state power
amplifiers all in a six-foot wide console
cabinet. Other products will include the
company's new, solid-state, stereo -disc recording amplifier system.
Check No. 78 on Reader Service Card
39
MAY 1969
www.americanradiohistory.com
AmericanRadioHistory.Com
This Month:
Equipment
Profiles
Sony/Superscope Model TC -770-2
Portable Stereo Tape Deck
H. H. Scott Model LR -88 Stereo FM/AM
Receiver Kit
Rabco Model SL -8 Tone Arm
Fairfax Model FX-100 Speaker System
Sony/Superscope
Model TC -770-2 Portable
A.C./Battery-Powered
Stereo Tape Deck
MANUFACTURER'S SPECIFICATIONS:
Model TC -770-2; 2 -track stereo/mono (also
available as Model TC -770-4, 4-track
stereo/mono). Max. reel size: 7 in. Speeds:
71/2, 33/4, 13/e ips. Heads: Four-erase, record, play 2 -track, play 4 -track. Inputs: Low impedance microphones, auxiliary. Outputs: line, stereo headphone. Frequency
Response: 71/2 ips, 40-18,000 Hz, ±2 dB.
Wow and Flutter: .09°/o at 71/2 ips. S/N:
4 -track-56 dB without SNR, 62 dB with
SNR; 2 -track-58 dB without SNR, 64 dB
with SNR. Harmonic Distortion: 2°/o at
0 dB line output. Dimensions: 16'/8" wide
x 513/46" high x 155/46" deep. Weight: 24
lbs., 11 oz. Price $750.00.
Portable, battery -powered tape recorders are a breed in themselves. They
--
have to be light enough to carry comfortably they must operate on batteries they must be flexible and if
they are to be used for professional
purposes, they must be of the highest
quality. Concerning the latter, it is desirable that they have speeds of 71/2 ips
for their professional applications, and
some lower speeds for those applications where they will be required to record for longer periods of time. It is
also desirable that they accommodate
7 -in. reels with the cover on, and their
-
operating characteristics must be comparable to studio -type machines. All
these attributes are offered in the Sony
TC -770, the only sacrifice being in the
weight department. The model tested
was the TC -770-2, which records and
plays two tracks, alid by throwing a
switch, additionally plays four -track
tapes. The TC -77-4 records and plays
four -track tapes, and the switch permits playing two -track tapes. Fig. 1
Fig. 1. Sony TC -770-4
portable tape recorder. The 770-2 model
is identical in appearance except for the
number on the
nameplate.
shows a typical 770, while Fig. 2 shows
the recorder with the top plate removed.
The unit is a handsome device, with
its pebble -grained black covering and
chrome hardware. The inside reveals a
chrome metal plate, with reel hubs
which accommodate 7 -in. reels, two tension rollers, and the capstan and idler.
The head cover is a casting which slips
over two slotted pins for location, and
locks in place with a thumb screw at
its rear. On the sloping front panel are
from left to right two monitor
-
-
push/push buttons to select source or
tape monitoring. Below these is the
power switch, and the inside of the
case is fitted with a plastic projection
which prevents the top being put on
unless the switch is in the OFF position.
To the right are the two VU meters,
with the record-level controls below
.
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.
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Y.
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111
with the top plate and
head cover removed.
Fig. 2. The recorder
them.These are dual concentric knobs,
with the smaller one for microphone input and the larger for auxiliary input.
Next to the right is a black button
which provides a battery test when depressed the VU meters deflect to an
indicated portion of their dials
the
left one for the 71/2-V amplifier battery
and the right one for the 10-V motor
battery. The track selector switch is
on the head cover. Next are two red
RECORD buttons which must be depressed at the same time as the FWD
key to start recording. Recording level
may be adjusted without running the
machine simply by depressing the monitor buttons for SOURCE. With these
buttons up, monitoring is from the tape,
and the meters indicate the recorded
level on the tape. At the right are the
four function keys-REwiND, FAST FORWARD, FWD, and STOP. These are interlocked so the FWD key cannot be de-
-
-
pressed while the fast -wind keys are
down without first depressing the STOP
key.
The front panel compartment is
accessible by opening a hinged door
downward. In it are the "SNR"-SonyMatic noise reduction-switch, shown
40
AUDIO
MAY 1969
in Fig. 3. Near the center are three
push -push switches which select the
speed-71/2, 33/4, 17/s ips. Next is the
limiter switch, then the speed -tuning
knob. In its normal pushed -in position,
the speed is fixed at the specified value.
Pull it out and rotate it to the right for
faster operation, or to the left for
slower, on playback only. This switch
is disabled in the recording mode. Next
come two playback control knobs which
set the output level. Above them, and
visible with the hinged cover closed, are
the power indicator lights-one for a.c.
and one for battery.
In an opening on the right side of the
case are two sockets-one for the a.c.
line plug or the 12-V battery cable plug,
and another-a DIN socket-for the
remote control cable, which is a furnished accessory. In a similar opening
on the left side, are the two Cannon
microphone receptacles, two phono
jacks for auxiliary inputs, and two
more for line outputs. A compartment
at the back holds the battery pack,
which plugs into the unit by means of
another DIN plug. All connections to
the battery pack are made with this
plug. The batteries are of the nickel cadmium type, and they run the device
whenever it is turned on, even though
the a.c. plug or the 12-V plug is in
place. The battery "floats" on the incoming power supply, and may be
charged from the a.c. line with the
power switch off.
The limiter circuit mentioned previously serves as a controlled voltage
divider, and affects distortion minimally. Even with 30 dB of compression,
the distortion is still a respectable
1.2%. This is practically unheard of in
any compressor or limiter which has
been measured by us heretofore.
The variable speed control will vary
speed (on playback only) about ±5%
from normal, which is more than adequate for any situation likely to be
encountered. The SNR control will add
a comfortable 6 dB to the S/N, and all
without affecting frequency response.
The circuit is essentially the same as
used in the TC -666D, described in these
pages in the February issue.
In all, the TC -770 series uses 55 transistors and 39 diodes. Thirty transistors
are used in the amplifying section, 4 in
the bias -oscillator section, 5 in the
SNR circuit, 13 in the speed -control
section, and one in the power supply.
In addition, there two more which control the power -indicator lights. If running on battery alone, one light is on,
lit by the collector current of one transistor. If the a.c. plug is in, there is an
a.c. voltage applied to the base of the
second transistor (through a diode),
AUDIO
MAY 1969
and its collector current lights the
lamp, at the same time shutting off the
first transistor and extinguishing the
battery lamp. If you are recording with
the a.c. line and power fails or the plug
is pulled out, there is no change in
speed nor any click-the machine continues to run without a flicker. Only the
lights change.
A single d.c. motor operates the
transport. On its shaft is an a.c. generator which furnishes the signal to the
control circuits. These circuits are factory adjusted to provide any of the
three speeds with an accuracy better
than 2%.
One of the tension rollers actuates a
microswitch so that power to the motor
is shut off when the tape runs out. The
Fig.
3.
while for 1%, it appears that the 202
might give better high -frequency response at the standard bias settings.
This is the first time these results have
been plotted in a Profile, and it may
give the reader some insight as to the
importance of correct bias settings for
each type of tape. The bias frequency
was measured at 168 kHz, which would
certainly permit recording as high as
34 kHz without interference or beating
with the fifth harmonic of the signal,
but more important, the bias is not
likely to beat with any harmonic of the
38 kHz used in multiplex stereo circuits. Of course, you might get a 14 kHz beat with the fourth harmonic of
the 38, but it seems most unlikely, even
if the fourth harmonic were strong
The open front compartment showing the auxiliary controls.
other simply keeps tension on the feed
reel, and, with the scrape -flutter filter
in the head assembly, completely eliminates scrape flutter, which is present in
some machines.
Performance
Figure 4 shows the frequency responses of the TC -770 to standard tapes
at 71/2 and 33/4 ips, as well as record/
playback responses at all three speeds.
Note the dotted curves for each speed.
It is our usual practice to use Scotch
202 tape for these measurements, and
the dotted curves show the responses
with this tape. The 770 instructions say
that it is aligned and biased for a more
standard tape, naturally Sony PR -150.
Inasmuch as the response with 202 was
not within specifications, we requested
a roll of Sony tape and remade the
measurements, with the results shown
in the solid lines. This does not indicate
that anything is wrong with the machine-only that its bias was set for the
Sony product. The same results were
obtained with the more common 111,
which is most similar to Sony PR -150.
Certainly for the 71/2 and 33/4 speeds,
we would recommend the Sony tape,
enough to beat with anything
Wow and flutter measured .08% at
71/2 ips, .09 at 33/4, and 0.16 at We, all
better than specifications. S/N measured 59 dB without and 65 dB with
SNR at 71/2, and only at 4 dB less at
33/4. The 3% distortion point occurred
10 dB above the indicated 0 dB on the
meter scales, with distortion around
1.2% at all frequencies from 50 to
10,000 Hz at the indicated 0 -dB level.
The microphone input signal required
to get a 0 -dB level was .04 mV with the
control at maximum, while 46 mV
would produce the reference level from
the auxiliary input. The output at the
line terminals was 0.775 V at the same
level, and the monitoring output for
8 -ohm phones was 54 mV, which provided a comfortable listening level.
Note that the limiting action, shown in
Fig. 5, indicates no increase in distortion over a wide range of input signals,
and that the limiting-or rather, compressing-action was very effective.
.
All of the operating controls work
smoothly with no hitches. For editing,
the head cover is readily removable,
giving good access to the heads them -
41
Equipment Profiles (continued)
Limiter
Off
71/2
5dB
3
3/4
Output
Limiter
On
Playback from standard tape
:Off
Sony PR -150 tape
---Scotch 202 tape
71/2 ios
.'
2%
1%
-
-30
-40
-50
-60
-70
-80
INPUT LEVEL FROM MICROPHONE (dB)
Fig. 5. Limiter -compressor characteristics: Solid lines show relative
outputs for the wide range of microphone input signals with the
limiter on and off. The dotted curves show the distortions under
both conditions.
5dB
-90
33/4
---------'
4
Distortion
%,
;On 3% 0
17/s
5dB
4
Record/playback at all three speeds
20
10k
1k
100
t
Fig. 4. Performance curves: Upper pair show responses to standard frequency tapes. Lower curves show record/play responses with
Sony PR -150 tape (for which the machine was biased) in solid
20k
lines, and with Scotch 202 tape in dotted lines.
FREQUENCY (Hz)
selves. They are completely exposed
with the cover off, and the usual grease pencil markings can be applied exactly
at the head gap-making sure to use
the correct head for the track configuration you are using. The remote control previously mentioned will start the
transport at a distance, leaving the
mode-recording or playback-undisturbed. It will not permit remote rewinding or fast forward winding, but
that is rarely needed from a remote
location anyhow.
The machine's speed accuracy holds
well until the battery voltages are be -
low the limits marked on the meters,
which ensures that recordings made in
the field will be compatible with those
made in the studio.
In evaluating the total Sony/Super-
scope Model 770, one must concede that
it is not a machine you would carry
around as you would a cassette recorder. It weighs too much for that
application. Since it is a professional
machine with important extra features
and 7 -in. tape reel capacity, it should
be viewed in that light. As such, its 25
lbs. appears to be amazingly light. In
fact, we would view the Sony/Super-
kit with a real hot front end, fairly high
power output, low distortion, and excellent operating flexibility. Besides
that, it's a good-looking unit when assembled; no "kit look" to this one. And
assembling it yourself saves money.
Most of the kit -building consists of
mechanical assembly of parts, and
Receiver Kit
1-Front view
of the H. H. Scott
LR -88 receiver kit,
after assembly.
Fig.
Stereo Separation: 35 dB @ 400 Hz. AM
30 watts per channel at 8 ohms. THD:
0.6°/o at rated output; 0.4°/o at 15 watts
rms/channel. IM: 0.8°/o at rated output;
0.690 at 15 watts rms/channel. Frequency
Response: Tape, Extra: 20 to 20,000 Hz
±1.5 dB. S/N Ratio: Tape, Extra: 80 dB;
Phono: 65 dB; Tone -Control Range: Bass:
±10 dB @ 50 Hz; Treble: ±10 dB @ 10
Tuner Section. Sensitivity: 200 AV (built-in
antenna; 9 AV (ext. antenna). Amplifier
Section. Dynamic (IHF) Power Output: 80
watts total at 8 ohms. RMS Power Output:
pleted unit) 17'/o" W
Price: $334.95.
MANUFACTURER'S SPECIFICATIONS:
FM Tuner Section. IHF Usable Sensitivity:
2.5 AV. S/N Ratio: 65 dB. Capture Ratio:
2.5 dB. IHF Selectivity: 45 dB. Frequency
Response: 50 to 15,000 Hz ±2 dB. Cross Modulation Rejection: 80 dB. Total Har-
42
Distortion
Check No. 45 on Reader Service Card
Here's a stereo FM/AM receiver
H. H. Scott
Model FR -88
Stereo FM/AM
monic
scope Model 770 as a superb tape deck
even if it were an a.c.-only machine.
With a built-in battery power supply
and a stereo system that maintains accurate speed, Sony has surely developed an exceptional unit that fills a
niche sorely needed by professionals
and other serious recordists. And if
$750 sounds like a lot of money, remember that you're getting a portable
that can also be used as a no -compromise a.c. tape deck. An added fillip is
a marvelous instruction book that includes a complete schematic.
(Mono):
0.6°/o.
FM
kHz. Power Bandwidth: 20 to 20,000 Hz.
Damping Factor: 30. Dimensions: (comx
15" D
x
5V2" H.
wiring output transistor circuitry, selector-switch, and all of the interconnecting cables between the various p.c.
boards. A view of the underside of the
chassis, after completion, is shown in
Fig. 2. All but one of the p.c. assemblies can be seen in mounted position.
The H. H. Scott silver-plated, FET
front end comes completely wired and
aligned. In all, the Model LR -88 has
a total of 34 silicon transistors, 24 diodes, 4 integrated circuits and 2 stabistors.
Our kit builder was asked about con AUDIO
MAY 1969
There's more to
the new Marantz
speaker system
than meets the eye.
(Lend an ear.)
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 in an
enclosure only slightly larger than a standard book shelf speaker. Yet, the power and
quality of the sound they deliver are cornparable to theatre speaker systems not only
twice their size but many times their cost.
The sleek, contemporary Imperial has a
I
smart, walnut cabinet with a hand -rubbed French lacquer
finish and is priced at $299.00. The elegant Imperial II,
t+~;*g
Iii'4+,`.*#i4i
3:5;;,#t+
V 1s,i,'iW,
. .! ` 4+i
i iu
++i+i,
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hand-crafted from selected hardwoods and
finished in distressed antique, features a
stunning hand -carved wood grille. It's you,s
for $369.00. Both possess 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.
THE SOUND OF MUSIC AT ITS VERY BEST.
B MARANTZ CO.. INC
AUDIO
MAY 1969
.
1969. MARANTZ IS A SUBSIDIARY OF SUPERSCOPE. INC. P.O. BOX 99C
SUN VALLEY. CALIFORNIA 91352
Check No. 43 on Reader Service Card
SEND FOR FREE CATALOG.
43
Equipment Profiles (continued)
struction of the kit, so before we deal
with the "finished product," here are
his comments:
"Instructions were excellent ... This
kit displayed exceptional design and
color diagrams
packaging concepts
were easy to follow. Parts were delineated by construction number and beautifully packed in foam separators.
Solderless connectors helped considerably were used."
Minor difficulties encountered were:
"... some screws had stub ends instead
of pointed (self -tapping type) and were
hard to start in self -tapping holes. One
wire length was missing."
Pre-cut and pre -stripped wire, with
critical sections being pre-wired and
pre -aligned, plus liberal use of printed circuit boards, simplifies construction.
And Scott's use of built-in meters for
alignment purposes, makes it all so
easy for the non -pro. It took our builder, who was admittedly meticulous
about everything, a total of 45 hours to
finish the stereo FM/AM receiver kit.
The instruction booklet, by the way,
is far more than just an assembly and
wiring manual. Pages 28 through 67 in
this 152 -page book are actual step-bystep instructions. Other sections include general kit construction tips, a
detailed parts list, test procedures and
alignment (without the need for any
test equipment) , installation and operating instructions, a section on
AM/FM receiver theory (fully twelve
pages), technical service instructions,
...
and a station log and custom-mounting
template (full size).
The Completed Receiver
The photo in Fig. 1 shows the front
panel of the LR -88. The upper half of
the panel is black, disclosing a well lighted dial scale only when the unit is
turned on. Two tuning meters are at
the left, one for center -of -channel tuning of FM stations, the other for peak
signal indication while tuning in FM
and AM stations. The expanded FM
scale has marks for every MHz, and
they are extremely accurate, deviating
from true frequency by less than a
"pointer width" at all points on the
dial. An equally well -calibrated AM
and logging scale are provided. To the
right of the dial scale is a tiny red spot
of light, illuminated in the presence of
a stereo FM signal; to the right of that
is a nicely balanced flywheel tuning
knob.
The lower half of the panel is in
anodized gold color and contains all
the other controls. A pair of microphone jacks are at the extreme left.
These are followed by a five -position
selector switch (mic., phono, FM, AM
and Extra), the usual balance control,
clutch -type dual bass and treble controls (each channel's tonal response can
be individually adjusted) and a loudness control which, in its counterclockwise position, turns off power to the
entire unit. We wish power on -off had
been accomplished in some other manner, say by means of one of the push-
Fig. 2-Rear panel
and underside view
of the LR -88
receiver. The latter
shows extensive
use of pre -wired,
printed -circuit
boards.
push buttons at the lower right of the
panel. As it is, there are seven of these
button switches for such secondary
functions as loudness on/off, tape monitor, mono/stereo, noise (high -frequency) filter, FM muting, remote
speakers on/off and main speakers on/
off. A stereo headphone jack completes
the front -panel layout.
The rear connection panel, shown in
Fig. 2, has two a.c. convenience receptacles (one switched, one unswitched) ;
a line fuse, as well as individual channel speaker fuses; antenna terminals
for FM, as well as a terminal for external AM antenna; speaker terminal
strips (barrier type, to prevent accidental shorts) ; a phono sensitivity switch
(either 4 -mV or 7 -mV sensitivity for
full output) ; tape input and tape output jacks; an access hole for the muting
threshold adjust (variable from 3- to
30-F,t,V sensitivity. And there's a new
feature we haven't seen on a complete
receiver before: a small slide switch
alters the remote-speaker output terminals from stereo channels to a monophonic mix of left and right channels.
This strikes us as a very good idea, in
that it permits the mounting of a single
remote speaker in another room (or
even one in each of two secondary locations) and, when thrown to the
"mono" position, affords a compatible
mono mix of program material while
the main speakers continue to provide
full stereo. Another suggested use (by
Scott) is the possibility of using a single remote speaker as a fill-in center
channel for overly separated program
material or two widely spaced main
speakers (because of decor necessity).
In such cases, a single remote speaker
is connected to either set of remote
speaker terminals, the mono -stereo remote speaker switch is set to "mono,"
and this single speaker then can be
placed mid -way between the two main
speakers to provide the needed third channel fill.
The AM loopstick antenna is plugged
into an appropriate socket at the rear,
so that it can be disconnected (and
even removed entirely together with its
protruding brackets) in the event that
an external antenna is used for AM.
The output transistors are mounted on
the rear surface, too, as is common.
Suitable protective covers are used to
prevent access to these devices, which
carry voltage on their cases.
Performance Measurements
We have long maintained that IHF
sensitivity alone does not tell the complete story concerning a product's performance as an FM receiver. Here is
another case in point. Although the
44
AUDIO
MAY 1969
Marantz announces
the end of
distortion.
(And the beginning of the new -generation IC amplifier.)
For the first time in audiophonic history, the all -new
Marantz Model 16 stereo power amplifier brings to music
lovers distortion -free amplification.
Marantz' new -generation integrated -circuit amplifier
eliminates intermodulation and harmonic distortion to
such an infinitesimal degree it cannot even be measured
by conventional test equipment!
The first in a new -generation series of stereophonic
equipment from Marantz, the Model 16 RMS eighty -
eighty stereo amplifier represents a significant advance
in the state of the art. It features
exclusive separate power supplies for total isolation of each
channel. This means there is
absolutely zero cross -modulation distortion. Now for the first
time, you hear individual instruments. Distinctly. Without annoying cross -talk from instruments
reproduced from the other
channels. There is absolutely no
sound leakage between channels. When you listen to
music through the Marantz Model 16, you will be listening to the purest, cleanest sound ever achieved by any
amplifier.
The new Marantz Model 16 stereo amplifier RMS
eighty-eighty means just that: 80 watts delivered per
channel. (RMS means continuous power-from the lowest to the highest reproduced frequency. Not the
"dynamic" or "peak" or "music power" that other manufacturers quote in their specifications. When Marantz
quotes 80 watts, Marantz mears
80 watts. Period!)
To truly appreciate how infi-
THE SOUND OF MUSIC AT
m MARANTZ
AUDIO
MAY 1969
CO. INC.
1969. MURANTZ S A
SUBSIDIARY OF SUPERSCOPE. INC. P.O. BOX 99C
nitely superior the $395.00
Marantz Model 16 stereo amplifier is, we suggest you visit your
local franchised Marantz dealer.
He will be pleased to furnish you
with complete details together
with a demonstration. Then let
your ears make up your mind.
ITS
VERY BEST.
SUN VALLEY. CALIFORNIA 91352
Check No. 45 on Reader Service Card
SEND FOR FREE CATALOG.
45
Equipment Profiles (continued)
1
-dB limiting
$
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-0
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20
1"
-30
IHF sens
2.5
0be
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-10
)..IV
II
11
-50
-60
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'L'output with "L only signal applied
audio output.75- kHz deviation
1
R
kHz
I=1
10 kHz
output,with "L only"signal applied
-30
noise
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ct -40
0.1
1000
100
10
1
20
INPUT SIGNAL (MICROVOLTS)
100
10k
1k
20k
FREQUENCY (Hz)
Fig. 4-Stereo FM separation, with 1 kHz and 10 kHz dual -trace
Fig. 3-FM (monophonic) characteristics of the LR -88.
photos.
Power bandwidth (1/2 power)
Fig. 6
stretches from 18 Hz to 23 kHz. Square Fig. 7-Tone control, loudness, and high Fig. 5-Total harmonic distortion and inter wave response at (A) 100 Hz and (B) 10
frequency filter action.
modulation distortion of the LR -88 rekHz is also shown.
ceiver vs. power output (rms watts).
-
3.0
+20
--
2.5
be
Z
2.0
O
15
8 -ohm load.
Single channel.
Both channels
1M
distortion
harmonic
distortion
driven.
+10
_watts
%
18
Loudness
H,
-10
IM
O
H to
-
0
Filter
L
5
-20
THD
\
0.5
(A)
10
20
30
40
50
60
100
POWER OUTPUT (WATTS r.m.s.)
Scott people claim a sensitivity of 2.5
p,V, and our sample come close to it
as shown in Fig. 3, actual FM performance seems better than that. For example, we logged no fewer than 43 FM
stations with adequate quieting, using
only an indoor dipole antenna. Of
these, 15 were in "listenable" FM
stereo. When we switched to an outdoor Yagi antenna, with the aid of a
rotator, we were able to pick up a grand
total of 51 usable stations (at least
30 -dB rejection of noise and distortion)
and the stereo number increased to 17.
All this in a suburban New York location. Now, 2.5 ¡IV IHF sensitivity is
not the lowest ever measured in our
labs, but this is a new record for number of stations received.
The feat is all the more remarkable
when you remember that the kit builder did not have access to a single piece
of professional test or alignment equipment. Whatever alignment was needed
was done simply by following the
Ez-A-LIGN® procedure given in the Scott
manual. Essentially, the tuning meters
of the finished receiver serve as the
necessary indicators during this ingenious alignment procedures. Other relevant FM characteristics are also shown
in the composite graphs of Fig. 3. It
should be noted that while THD in
46
(B)
1k
10k
20
100k
100
10k
1k
20k
FREQUENCY (Hz)
FREQUENCY (Hz)
mono was actually better than claimed
(0.4% instead of 0.6%), it did reach
1.0% in the stereo (no manufacturer's
spec given). Signal-to-noise was exactly 65 dB, as stated and full limiting
occurred at an input of only 3 microvolts.
As for amplifier performance, the
manufacturer's specifications were easily met or exceeded. For example, rated
distortion was reached at 32 watts r.m.s.
per channel, as compared with 30 watts
claimed. THD with an eight -ohm load,
as well as IM distortion, are shown in
Fig. 5. Power bandwidth, shown graphically in Fig. 6, is seen to extend from
18 to 23,000 Hz; again, better than
manufacturer's claims if one bases the
measurements upon 30 watts rms per
channel of full output. Tone -control action is illustrated in Fig. 7, in which
the loudness compensation characteristic as well as the high -frequency filter
action is indicated. It must be pointed
out that this filter is not very effecive
because of its limited slope (6 dB per
octave) which acts like little more than
an auxiliary treble control with a
slightly shifted cross -over point.
Square -wave response at 100 Hz and
10,000 Hz, shown in Fig. 6, is typical
of most all -in -one receivers, and is
deemed to be adequate.
,
Scott multiplex decoder circuits are
noted for their sophisticated and excellent design, and the one built into the
LR -88 is no exception. Particularly
noteworthy is the fact that separation
of at least 25 dB between channels is
maintained from 50 Hz to 10,000 Hz,
with fully 35 dB of separation measured at mid -band frequencies, as
shown in Fig. 4. Accompanying photos
taken of a dual trace 'scope screen visually confirm the meter measurements.
Threshold of switching from mono to
stereo FM is positive, and occurs at
about 4 microvolts of r.f. input signal.
At this minimal signal level, stereo performance is fairly noisy, of course, but
the mono -stereo pushbutton switch enables the user to defeat the automatic
switching feature and listen to such
marginal stations in a mono mode.
When the switch is depressed to mono,
the stereo indicator light is extinguished, to remind the user that he is
not listening in stereo, station announcements notwithstanding.
All in all, if kit building is your forte
(or even if you've never tried it for fear
of possible complexity), the Scott LR 88 offers a most competent design at
a price well below that for an equivalent factory -assembled unit.
Check No. 84 on Reader Service Card
AUDIO
MAY 1969
Moto-Courtesy of Hi -Fl Tiade News':.
It's taken you only a year to make Pioneer one of the
fastest selling headsets in America today!
Take our SE -50 (so many of you have!), its quality
literally speaks for itself. We've miniaturized Big
Speaker System design and sound into each of its
lightweight, comfortable, vinyl covered earcups. It
features cone -type woofers and mylar-diaphragmed
tweeters, resulting in extraordinarily smooth response
from 20 Hz to 20 kHz. The SE -50's performance and
features, at only $49.95 are in a class by themselves.
That sounds astounding, but so does the SE -50!
The Pioneer SE -20 ($19.95) and the Pioneer SE -30
($29.95) equal and surpass the performance of headsets far more costly and every Pioneer headset is
supplied complete with its own permanent storage
case. Pioneer has a reputation to live up to, and these
headsets are fine examples of how we go about it.
Why don't you put us on? And make an enormous
sound discovery for yourself-right between the ears!
only at fine high
Insist on a Pioneer demonstration
fidelity dealers. Or write Pioneer for full details on
the entire Pioneer component line and the name of
your nearest franchised Pioneer dealer.
-
SE -30
SE -20
SE -50
PIONEER
,eD
...More
Value All -Ways!
PIONEER ELECTRONICS U.S.A. CORP., 140 Smith Street, Farmingdale, L.I., New York 11735
AUDIO
MAY 1969
Check No. 47 on Reader Service Card
www.americanradiohistory.com
AmericanRadioHistory.Com
(516) 694-7720
47
Equipment Profiles (continued)
Rabco SL -8 Servo -Driven,
Straight-Line Tone Arm
MANUFACTURER'S SPECIFICATIONS:
Dimensions: 33/4' high (adjustable); 14"
long. Weight: 3 lbs. Tracking Force: 1/4
gram minimum. Servo System: Crossed -
wire precious metal contacts operate a
precision servo motor through a single transistor amplifier. Lift at end of record
is automatic. Power supplied by a standard
"C" cell. Battery life roughly equivalent to
shelf life. Pickup mounting: Cartridges
with standard 1/2" spacing mount with
two screws. Holder can be adapted to any
other spacing. Cartridge holders are interchangeable. Output connections: Standard phono jacks provided on the frame.
3 -ft. cable supplied. Price: $149.50. Accessories described in text.
Here's a phono cartridge tone arm
for audio buffs who can put their money
where their hearts are. It's a straightline -tracking tone arm for manual turntables. A servo drive system inhibits
the tone arm from moving in an arc
while the cartridge moves inward on
the disc being played. By moving in a
straight line toward the center of a record, the tracking -angle error exhibited
by conventional tone arms is eliminated.
As everyone who has ever seen a
professional disc cutter in operation
knows, the head is carried on a lathe
which moves the cutting stylus along
the radius of the recording blank. It
would thus seem obvious that the way
to move the playing cartridge would be
exactly the same along the radius.
While the problem was solved by Edison around 1895 by driving the playing
stylus along a cylindrical record by
means of a threaded rod-just as, in
-
chanical drag on the arm or carriage,
Mr. Johnson suggested a lamp which
illuminated either of two photocells,
depending on the position of a mask.
The idea would have worked perfectly,
although the device would have been
unduly complicated.
The Rabco SL -8, however, employs
a simpler geared -down d.c. instrument
motor, and the contacts are precious
metal wires which exert a minimum of
"drag" on the carriage.
The arm itself is counterweighted,
and swings on two sets of pivots-the
horizontal ones being just as close to
the record surface as possible, which is
considered good practice. The vertical
pivots are directly under the center of
the carriage, which rides on four nylon
rollers that travel along the main channel-an extruded aluminum channel.
The lift bracket controls the raising
of the arm, and when the arm is in
the raised position, it is centered by
the duo -conical shape of the clamping
screw which holds the tubular cartridge -holder end in place. When the
lift bracket is depressed, the stylus
lowers to the record surface, and at the
same time the carriage is clamped to
the ball -chain driving loop. An extension from the arm carries a 30 -mil gold
wire in a vertical plane. Any inward
movement of the arm with respect to
the carriage causes the gold wire to
contact a thin spring wire of platinum
alloy which energizes the transistor
amplifier and drives the servo motora Swiss instrument type geared down
so that it takes 90 sec. for it to complete one revolution. This motor, the
amplifier, the battery, and the output
terminal strip are all mounted in a
cast aluminum housing at the left end
effect, the current recording equipment
operates-it has not been so simple for
reproducing a disc record, which may
be cut anywhere from, say, 80 grooves
per inch (for a 78) up to about 250
for an LP.
Those who have followed hi-fi for
years have seen several different devices designed to maintain perfect per-
pendicularity to the radius of the record
along which the stylus moves, regardless of position of the arm (the B -J
arm, for example) , and the lateral moving cartridge holder of the Bard
arm, which depended upon the stylus
itself to impart the necessary motion
to the carriage. Neither of these is still
on the market. In the case of the B -J
arm, the many additional pivots caused
too much friction to be overcome by
modern light stylus forces, and the
high compliance of modern cartridges
proved too much for the Bard, although
both of these configurations had their
advantages which were apparent when
stylus forces were in the 3- to 5 -gram
range.
As recently as May, 1966, the Servo
Groove Tracker was presented in these
pages almost as a home construction
article, and about the same time another article was submitted, but rejected in favor of the one which appeared under the authorship of Arthur
G. Johnson.
The requirements are well knownthe arm should move laterally along a
track parallel to the radius of the record so that the cartridge is constantly
perpendicular to the radius, and it
should either move so freely as to be
impracticable from the construction
standpoint, or it should be moved by
a servo mechanism. To avoid any me-
Fig. 1. The Rabco SL -8 arm mounted on the Thorens TD -150 turntable, and drawing with parts callouts.
+
Terminal Up
Lift Switch Button
Release Latch Lever
Counterweight
Battery Case
Cover
Lift Bracket
AUDIO
48
www.americanradiohistory.com
AmericanRadioHistory.Com
MAY 1969
Which of these comparably
priced, top-quality speakers
utilizes the new principle
of electronic suspension?
only LWE.
®o
BOSE -901 $496*
LWE
I
$500**
AR -3a $500**
For years now inverse (negative) feedback has been used in
Hi-Fi amplifiers to improve performance. Recently LWE research has uniquely adapted the same principle to control the
resulting in dramatispeaker cone electronically at all times
cally improved speaker performance. No resonant mechanical
or acoustic mass -spring system can influence low frequency response. Transient response is unrivaled. Room Gain
Control is provided to compensate for
room acoustics.
-
LWE
LWE speakers are available in four basic sizes to meet the power and
space requirements of any room. You choose from a wide variety of
woods and finishes, as well as unfinished kits. LWE prices range from
$75 to $3,000 and include LWE's standard five year speaker guarantee.
Hear the LWE at your dealer or write for LWE's "Sound of Excellence"
Brochure.
ACOUSTRON CORPORATION
2418 BARTLETT STREET/HOUSTON.
TEXAS 77006/PHONE
(713) 524-7407
*Manufacturer's suggested retail' price for twin speakers and "Equalizer." **Manufacturer's suggested retail price for twin speakers. Single speaker is $250.
AUDIO
MAY 1969
Check No. 49 on Reader Service Card
49
Equipment Profiles (continued)
Fig. 2. The working
parts of the arm in-
verted to show the
construction,
together with a closeup of the amplifier/
servo motor housing.
of the track. The motor is fitted with a
pulley which is grooved to fit the ball
chain, and the other end of the chain
loop feeds over a nylon pulley at the
right end of the track. Most of these
the Rabco arm nicely, and the ingenious experimenter could undoubtedly figure out some way to mount it
on other turntables.
details can be seen in the accompanying figures.
At the end of the record, the arm
moves more rapidly because of the run out groove, and the gold wire contacts
a second platinum alloy wire which
energizes a second motor on the carriage to release the lift bracket, thus
raising the cartridge from the record.
If the user wishes to lift the arm before
the end of the record, he depresses the
release latch lever on the carriage
which mechanically lifts the arm, or he
depresses a red button on the top of the
motor housing which energizes the lift
motor. The "C" cell fits into the casting and is held in place by a cover
which also serves to make contact with
the positive pole of the battery.
The Rabco arm must be mounted
directly on the motor plate, or on some
part of the turntable structure that
moves as the platter does. Thus it is
suited for use with the Thorens TD150 table, on which the test sample was
installed. This turntable provides the
needed spring mounting from the base,
yet provides a place for mounting an
arm so it will be rigid with the turntable, for no relative movement between the arm and the center of the
platter can ever be permitted. Several
Thorens models should accommodate
Performance
Fairfax Bookshelf
Loudspeaker System,
Model FX-100
cabinet which differs from most other
ported cabinets in that the port tube is
MANUFACTURER'S SPECIFICATIONS:
Two-way system. Woofer -8 in. dia. ducted
port; Tweeter, 3'/2 -in. cone. Crossover
frequency: 5500 Hz. Frequency range: 3020,000 Hz, Power Handling Capacity: 30
watts. Impedance: 8 ohms. Dimensions:
21" x 12" x 8" deep. Weight: 24 lbs.
Price: $89.50.
This new compact bookshelf model
employs two speakers in a ported reflex
50
Without question, the Rabco arm
does what it is supposed to do, and does
it nicely. There is sufficient latitude for
the arm to sway slightly enough to
accommodate minor eccentricities of
the record movement without energizing the servo motor, but even if it did,
the arm would only move slightly in the
proper direction and then stop and let
the cartridge "catch up." Then the
cycle would start all over again.
Obviously, there is no skating-since
skating is the result of the geometry of
angled arms and their overhang positions-so no anti -skating provision is
necessary. And because the only work
the stylus has to do-other than track
the groove and wiggle its magnet or its
armature so as to produce the signalis to move the arm against the fine
platinum alloy spring wire, the cartridge is able to track at usually well
under the cartridge -manufacturer's
specification. The Shure V15 -II, which
was fitted on our test sample, would
track anything we gave it at 1/2 gram,
and if we sat still and didn't walk
around on the not -too-solid floor, it
would track at 1/4 gram on most material. Some heavy modulations would
not come through as they should, so we
Fig. 1-Fairfax FX-100 Loudspeaker system.
would recommend 1/2 gram as the minimum for this cartridge, assuming a
solid flooring.
The driving motor can barely be
heard by placing the ear close to the
track, but could not be heard through
the reproduction at all. At first we
thought that some form of dashpot
would be desirable to slow the dropping of the stylus to the record, which
seemed to be rather abrupt, but dropping a half -gram a quarter of an inch
(at most) couldn't possibly hit very
hard, so we quit worrying about that.
The track is readily adjustable to
any platter height, and stylus force is
adjusted by turning the counterweight
one full turn for each gram of force
desired, after balancing the arm completely. The counterweight has a
marker on its back so as to permit
accurate adjustment.
Our only suggestion for a change,
after rejecting the few other ideas we
first had, would be to color the release
latch lever red instead of the yellow
now used. The electrical release button
is red, and the yellow is jarring, in our
opinion. We know the principle is right,
and we must admit that the embodiment of the finished product works
perfectly, as far as we can see. It is a
delightful device.
As mentioned, our test sample was
fitted with a Shure V15 -II cartridge,
and it was mounted on a Thorens TD 150. Factory fitted, the cartridge is
an additional $67.50, and the table is an
additional $85.00. The base, in oiled
walnut, is another $12.00, making a
total of $314.00 for the complete assembly. Additional plug-in cartridge holders are $7.50 each, for those who must
have a number of cartridges ready to
use.
This is not inexpensive, but you get
a lot for your money: minimized record and stylus wear, superb reproduction, and perfect anti -skating compensation (since none is required).
Check No. 134 on Reader Service Card
cut off at an angle of about 45 deg.,
rather than perpendicular to its length.
The tube itself is 21/2 in. in diameter,
41/2 in. long at its longer dimension, and
2 in. long in its shorter. This form of
port should tend to smooth out the
lower end of the spectrum, much in the
same manner as an exponential horn
does if it is large enough to reproduce
lows. The speaker puts out a good level
at 60 Hz, without doubling, and a measurable output up to 22,000 Hz, although it is down considerably at that
frequency, as one would expect.
Check No. 51 on Reader Service
Card.-
match your
auto -turntable to
the quality of a
Sherwood 6000
The No -Compromise 'Sound Center" for Limited Space.
Now get maximum performance in a mini -space! Sherwood's new
6000 is the full -feature, 120 -watt music power AM/FM "STEREO
SOUND CENTER" that provides unlimited choice of matching
components. Choose any automatic turntable'-any magnetic
cartridge. Mount perfectly on the pre-cut oiled walnut cabinet.
Choose any speaker. Big or little, low or high efficiency. Your
Sherwood 6000 has the power to spare for clean, pure, wall-to-wall
sound. Compare features. FET FM tuner for ultra -sensitivity.
Front -panel tape dubbing and headphone jacks. Stereo and mono
extension speakers. As the high-performance heart of the finest
component system, the Sherwood 6000 takes no more space than
"compromise compacts." It's the modern solution to big sound in
small space. Features: 120 watts music power, 1.8 µv II -IF sensitivity
-95 db crossmodulation rejection, automatic FM stereo switching,
zero -center tuning meter, front and rear panel tape inputs/outputs,
mono speaker output. Perfect match for your 6000-Sherwood's
new Berkshire II spea<er system: slim 9" deep cabinet with 12"
woofer, 5" mid range, 160° "omni-polar" tweeter,
28-22,000 Hz response.
NNOVATORS IN
FINEST CUALITY TUNERS / AMPLIFIERS / RECEIVERS / SPEAKERS
4300 North California Avenue, Chicago, Illinois 60618
Write Dept. 5-A
'Any of the Dual (current models) or Garrard SL55 or SL65.
WMr
Equipment Profiles
(continued)
The impedance of the system shown
in Fig. 2, measured relatively smooth
from 150 to 20,000 Hz, varying from 6
ohms at 5500 Hz (the crossover frequency) to 101/2 ohms at about 1200
Hz. The two low -frequency peaks are
at 90 and 23 Hz, respectively, with impedance of 20 ohms at the higher and
24 ohms at the lower -frequency peak.
32
T.,
28
E
24
-
20
ó
crossover frequency
U I
100
1k
10k
20k
FREQUENCY (Hz)
Fig.
2-Impedance curve measured at the
terminals of the FX100.
It has been our experience that when
the lower peak (there are always two
in a reflexed speaker system) is the
higher, the speaker tends to give the
impression of having more "low bass"
than _t does if the lower -frequency
peak is lower in impedance than the
upper peak. That impression is borne
out in listening when the speaker is on
the floor. Raise it off the floor and it
apparently loses some of its lowest response.
We found the terminals on the
speaker input strip to be too closely
spaced. Thus the user should avail
himself of spade terminals for making
connections to avoid the possibility of
a single strand of the connecting cable
shorting to the adjacent terminal, with
the consequent possibility of damaging
the amplifier output transistors (or at
least blowing fuses). The high -frequency level control, also mounted on
the terminal board, provides for an adjustment of treble response to accommodate the room environment over a
range of about ±3 dB, which is adequate for normal installations. Any
more than that and the user should
consider taking another look at his furniture, drapes, and so on.
We tried FX-100s on a wide variety
of program material, including both
male and female speech, and found
them within the usual limits of bookshelf -size speakers in its price rangethat is, with a falling off of the lower
bass frequencies, and with a loss in
high -frequency response at more than
30 deg. off axis of the tweeter. There is
a slight chestiness in male voices, indi-
"Like hearing 500
other exhausts...
all behind me:'
cating a bump in the response in the
100-150 Hz range. The tone -burst
photos, shown in Fig. 3, indicate fairly
good transient response and little hangover, both in the 1000 -Hz bursts at (A) ,
and in the 6000 -Hz bursts at (B).
Fig. 3-Tone-burst response at (A) 1000
Hz, and (B), 6000 Hz.
Assuming, therefore, that the speakers are placed on the floor or in a
bookshelf near an adjacent wall, the
FX-100's would be a good choice at
$89.50 each. They are efficient in comparison to the average acoustic -suspension types, and show no objectionable
peaks throughout their range. Concerning the former, one need not have a
powerhouse amplifier to drive it satisfactorily; a ten-watter would be adequate. And the absence of major peaks
in response gives the Fairfax -100 an
overall listening quality that could be
described as smooth, with a balance between lows, midrange; and highs that
has been well chosen.
Driver Ritchie Pelham had
just one question. "How do
they get so much sound out
of such a little box?" "Never
mind how," we said. "We
just do it." And we do.
When we introduced the
Ultra -D our competitors
asked themselves the same
-
question. Product reviewers
and critics raved
said it
was the equal of systems
costing twice as much. It
has since become an in-
Check No. 135 on Reader Service Card
dealer's. Its big sound will
open your ears. Its style and
size will open your eyes.
And its low price will open
your wallet.
ULTRA -D features 10" ultra -linear
woofer, 4" midrange speaker, 31/2'
direct radiator rigid diaphragm
- -
tweeter with aluminum voice coil
30 Hz to beyond audibility
23 13/16 x 117/e x 93'
24 lbs.
Also featured: STUDIO PRO 120A
FM/stereo receiver, nation's only
"certified" receiver.
-
dustry yardstick, against
which other compact systems are measured.
To everyone's amazement
(including our own) we've
even managed to improve it
making today's Ultra -D a
more outstanding value than
-
ever.
-
hear it
Why not see it
now, at your University
Listen
...
University Sounds Better
UNIVERSITY®SOUND
INC.
Of 1.11 ([email protected] ALrf
C.
ON
BOX 26105
52
OKLAHOMA CITY, OK
Check No. 52 on Reader Service Card
73126
Check No. 53 on Reader Service Card
ÿ
/
(ic;1i1DE1_7)
i`/``¡
This is the f.-601OJ,
top of the TEAC tape
deck line. Ali these are
just a coup!? of itt
supersonic.3yeakt-iroughs:
Unique phase sensing auto
reverse operates electronically at
any chosen çoint cn tt-L tape. Or it
can take a sensing foil if desired. BLit con't
look for this system on anybody e se's machine.
Separate h&-cds fc- record a -d pla}back allcw
off -the -tape ronif)ring whit_ recording; most other
machines in this price range can monitor the
sound sour:a only..
What's the tarries- to your completa sound enjoyment?
Chances are, TEAC has broken that, too.
Breaks
the sound
barrier.
Exclusive symmetrical control system Dual -speed hysteresis synchronous motor for capstan drive 2exclusive
-current outer rotor motors for reel drive Pause control Unique tape tension control 4 heads, 4 solid-state amps,
A -6010U eddy
all -silicon transistors Independent LINE and MIC input controls
TE
c
O
America
Corpaoratido
ofvenue
Aon
000D Color
Santa Monica, Calüfornia 90404
T2
CLASSICAL RECORDS
Edward Tatnall Canby
(Continued from page 14)
Schoenberg: Transfigured Night. Vaughan
Williams: Fantasia on a Theme of Thomas
Tallis. Strings of the N. Y. Philharmonic,
Mitropoulos. Odyssey 32 16 0298 (sim.)
stereo ($2.50)
Schoenberg: Transfigured Night. Loeffler:
A Pagan Poem. Leopold Stokowsky and
His Orchestra. Seraphim S 60080 stereo
($2.50)
Transfigured Night (Verklaerte
Nacht) , composed in 1899, is still
another of those near -modern works
which exists in more than one format,
and is highly "interpretable"-depending on which elements the conductor
feels like bringing to the fore. In one
sense, it is the ultimate and final Romantic piece, straight out of Tristan.
In another it is the beginning of
Schoenberg atonality (that, too, out of
Wagner). It is super-passionate-but
can be toned up, or toned down, to
taste. Here are two reissue versions by
two superb older conductors, totally
unlike.
It is good to find Mitropoulos reappearing. He was one of the great
ones, though too belatedly recognized
and not very popular when he was in
New York. (He modernized a bit too
fast for local tastes.) But his Schoenberg is of the old school, all shrieks
and sobs, carried to the ultimate passion. This is the way I always used to
know it-and hate it. (I detested passionate music as a youngster; I was all
for neo-classical restraint.) One vital
point that makes me love this version
now-it is in tune. The Schoenbergian
Wagner -type harmonies change so fast
that many orchestral string players
simply do not hear what is happening,
especially in the very high-pitched passages, hard enough to hit accurately in
any case. So they sob excruciatingly out
of tune. Not so here. Mitropoulos knew
what he was doing. Good man.
As for that unpredictable old sob expert, Stokowski, he is all modern retraint in his version. The piece (like
Bartók's Music for Strings, Percussion,
and Celesta) was originally "chamber
music," one instrument to a part, but
was re -arranged by Schoenberg for
string orchestra with some passages
still played on solo instruments. Where
Mitropoulos plays these down you
hardly notice them-Stokowsky plays
them up and tones down the big climaxes to such an amazing degree that
-
56
one hears almost a new piece, semichamber-like and not at all over -passionate. Very interesting.
The Mitropoulos "stereo" derives
from Columbia's ML 6007, which would
be one of the very earliest LP releases,
not even taped, back in 1948. The stereo
is, thus, simulated, even if it doesn't
say so. Somewhat grainy sound by
present standards but not bad, consid-
singing (same effect appears among the
Symphonies) , lots of innocuous little
folksy melodies and much thumping
and bumping of percussion plus a good
deal of the then -new jazzy sort of
rhythm. No great shakes, and pleasant
home listening today. Maybe it's as
well we are spared the actual production!
ering those screetching strings. Don't
know where Angel got hold of Stoky
"& His Orchestra," but the recording
seems fairly new and in true stereo.
You can have the two accompanying
works. Loeffler's Boston -bred Pagan
Poem, of the early part of the century,
is a big, turgid piece of American impressionism with some famous trumpet
passages, including a walk-on trio of
them at the end-this is not a convincing version of the music. As for the
Tallis Fantasy, it always has seemed
to me a lugubrious and utterly dated
elaboration of poor Tallis's original;
Tallis is very good on his own, thank
you. Good friend of mine, even if he
did die in 1585.
Performances: B
Performances:.B+
Milhaud:
Six
Sound: B
Little Symphonies; L'Homme
et son Désir. Soloists, Orch. of Radio Luxembourg, Milhaud. Vox Candide CE 31008
stereo ($3.50)
Symphonies? With Milhaud, be ever
prepared for surprises. Part of the
"French Revolution" of the period after
WW I was a conscious slapping-in -theface for every basic tenet of the older,
more genteel music. Since the Symphony was the 19th century's ultimate
form, Milhaud, you can guess, must
slap it down. These are tiny little
morcels, only a few moments long and
deliberately of an inconsequential effect-though there is much Art concealed in their varying, etude -like instrumentations. They are also, of
course, tinny, squeaky, saucily dissonant and often inelegant that was
part of the deal. Accept all this, and
-
you'll enjoy the whole business. Milhaud was a good craftsman. Still is.
"L'Homme et son désir" was a 1921
ballet, in the days when ballet was the
biggest source of shock in the new
Revolution. No use going into the outrageousnesses of the actual performance-that had people foaming at the
mouth. (Was this the one where the
audience arrived for the premiere, to
find the cast had taken off for a vacation? Big joke.) What you will hear in
the audible music is a lot of wordless
Sourd: B+
Prokofieff: Symphony No. 2; Lieutenant
Kije Suite. D. Clatworthy, bar., Boston
Symphony, Leinsdorf. RCA Victor LSC 3061
stereo ($5.95)
Prokofieff: Symphony No. 2; Symphony
No. 7. USSR State Radio Symphony, State
Philharmonic Orchs., Rozhdestvensky.
Everest 3214 (sim.) stereo ($4.98)
Two choices here for the loudest,
brassiest, most dissonant of Prokofieff's
symphonies, the No. 2, a work straight
out of the depths of the 1920s and heretofore tactfully ignored-for it is an
earful! But today, we are beginning to
enjoy this kind of earful. It is so very
"modern," and so very dated. Rather
nice to hear all that old fashioned cacophony, especially in stereo hi fi. The
two discs offer contrasting material to
accompany No. 2. Everest has the last
of the symphonies, No. 7 of 1952, a
sweet, ingratiating, nostalgic piece and
the last work the invalid composer
managed to complete. From Boston, on
RCA Victor, we get the familiar Lieutenant Kije, the man who never was,
his little .trumpet tune hopping unexpectedly from key to key-but here
with a difference. Two items in the
original film score were sung by a baritone; here these two revert to the original format, for a change. (I prefer the
instrumental version, thanks.)
RCA's Symphony No. 2 is a big, fat,
shiny production, massively recorded,
as befits the august BSO. Good performance. Everest's, via the USSR
Radio Symphony (assuming they
haven't reversed their labeling-see below) is even a little better, a drier
sound and a tighter playing to emphasize the 1920s seriousness of all this
dissonance, an effort by the young
Prokofieff to show that he could be as
modern as anybody at the time. This is
a true stereo recording if I hear it
rightly, and a good one of its dry sort.
Everest's No. 7, on the reverse side,
has the same conductor, but the other
orchestra-whichever one it may be. It
is well enough played, though I have
heard more persuasive versions, even
AUDIO
MAY 1969
including Ormandy's on Columbia. But
the recording on this side is another
story. As you flip, the sound deteriorates; this is out of a wholly different
set-up, even with the same conductor.
Moreover (says my ear), this appears
to be a simulated stereo, out of a mono
original, even if it doesn't say so. And
those vague stirrings in the background-are they a "live" audience? Is
this from a broadcast? Could be, even
if, supposedly, the other side is the
"Radio" orchestra. (The ascriptions are
casually reversed, you'll note, as they
appear on the backside of the jacket.)
So who knows? The conductor does.
He conducted both. Go ask him, if you
want to know.
Just to confuse the issue, I note that
Angel also offers the same Symphony
No. 7 with the very same conductor, on
its Melodiya label! There, the orchestra is listed as the Moscow Radio Symphony. And the recording on that one
is in full stereo.
One thing is definite. It'll cost you
more to hear No. 7 conducted by Rozhdestvensky via Melodiya, the official
USSR recording outfit.
long for its various messages, and more
professional than original. Good listening just the same. The earlier Roussel
is in a similar vain, out of 1934, also
very expert and rather glibly complex.
Nielsen, the Great Dane who is now
having a Revival, wrote his little Opus
1 Suite, played here, back in 1888. For
its time it must have been strikingly
modern; to our ears it is a bit amateurish, diluted Grieg, not at all pretentious
(which is in its favor) and merely too
long. What Opus 1 isn't too long?
Only the Hindemith Trauermusik
(Mourning Music), a short piece written on the death of King George V in
1936, comes a real cropper here. Just
doesn't make sense and it's a good
piece. The Italians sadly miss its entire strengths, the very Germanic
"dotted" slow -movement rhythms, the
pointed dissonances, the passionate
Teutonic dignity. A fine viola soloist,
even so.
What will interest the general music
listener here is not so much the Sills
vocal fireworks as the curious period
sound of these numerous excerpts from
the two Italians of the first part of the
19th century, Bellini and Donizetti. It
is a sort of double-feminine Rossini, a
Mozart style gone all sugar, a gentle
yet remarkably artificial kind of singing, quantities of the sheerest vocal
ornament crusted onto the thinnest of
fragile harmonic foundations ... it was
from this that the Wagnerian heavy-
Performances: A- to C+ Sound:. B+
Performance: B+
B-
I
Beverly Sills. Bellini and Donizetti Heroines. Vienna Volksopern Orch, Akademie
Chorus, Jussi Jalas. Westminster WST 17143
stereo ($4.79)
Though it isn't exactly mood-music
in effect, the sound of this superbly
skillful Italian string group remains
one of the sensations of today's music
listening. Once hailed by no less a
Maestro than Toscanini, I Musici were
one of the first of the new-style virtuoso groups of a dozen or less players,
smaller than an "orchestra," larger
than a chamber ensemble, and ideal for
recording (though I Musici was primarily a concert organization). I Musici's precision is now fantastic. The
recorded sound by Philips is a model
of stereo string portrayal. Normally,
I Musici has played older music, often
of the Baroque period and largely out
of Italy. Here they go modern, if conservative -modern.
The most imposing and longest work
is by the Swiss Frank Martin, now in
his late seventies. His Etudes for String
Orchestra though composed in 1956 are
in the manner of the Thirties, neoclassic, with skillful suggestions of
earlier Stravinsky, Hindemith, even an
almost -quote straight out of Bartók (a
pizzicato scherzo). It is superbly written for strings and sounds out most
impressively, but for my ear it is too
All coloratura sopranos emulate the
proverbial canary-but as time marches
on, their song -style changes. And, also,
it depends on what country you're
from. Beverly Sills comes from the Boston region, as of today, but she travels,
as can be noted from the above. She
has been a recent sensation in New
York opera; she is one of those singers
who mass-produce the world over with
no trouble at all. She mass-produces
here, faultlessly.
No-her exploits do not hark back to
the great days of the golden age, however brilliant. Her sound is strictly of
today, and out of the U.S. at that, and
not in the slightest like the famed
European coloratura voices of recent
memory, nor those of a half century
ago. She has the characteristic strong
vibrato of our time, the complicated
yet white-sounding tone color (the earlier singers produced a thinner, more
brilliant tone almost without vibrato)
the somewhat indifferent "scale," that
smooth progression of color from low to
high notes that once was the special
pride of a good singer, the somewhat
breathy production, all of which mark
the current product of the singing
teacher's art. Typical, if Grade A in
current terms.
Performances: A, A+ Sound: A,
Musici Play Works by Martin, Hindemith,
Roussel, Nielsen. Philips PHS 900-198
stereo ($5.98)
AUDIO
-
Specialties
weight reforms took off!
Sills produces the fireworks with
aplomb and ease; you get the feeling
she could do it all night with one eye
opened. But it really isn't very exciting.
No tension in it. There isn't much in
the music itself for her to work on.
(Yet some of the old gals, around 1900,
could make your hair stand on end in
this sort of music. A different singing
league.)
Sound: B
National Anthems of the World. Vienna
State Opera Orchestra. Everest 3239 stereo
($4.98)
The assembled flags of the United
Nations make a colorful display, as per
the cover of this record; the collected
anthems are something else again.
Everest's "orchestra" is in fact a
ponderous brass band of the tubby,
thumpy sort, and nary a string to be
heard. Nineteen ponderous anthems,
one right after the other, and each solemnly introduced by an official drum
roll (gotta maintain the diplomatic
niceties)
except, inexplicably, Israel
and Japan. Each one played with all
the pomp and circumstance that national pride presumably requires. And
all nineteen, in this case, done up with
a wholly Austrian weightiness even
unto the Star Spangled Banner, which
-
-
is full of wrong notes.
It's like a nineteen -course state banquet, every course a fat hard-boiled egg.
There are a few amusing side notes.
Israel's anthem seems to be the English
tune "I had a little nut tree, nothing
would it bear" put into a minor key.
"God Save the Queen" sounds, as always, like "My Country 'tis of Thee,"
which in fact it is. The Swiss anthem
"Rufst du mein Vaterland" sounds like
"My Country 'tis of Thee," which it
also is. Whatever happens when the
Switish and the Brish get together?
Performance: Heavyweight Sound: B
57
MAY 1969
www.americanradiohistory.com
AmericanRadioHistory.Com
Jazz
BERTRAM STANLEIGH
Jelly Roll Morton
EACH TIME RCA Victor brings out
a new collection of Jelly Roll Morton reissues, I am bowled over once
more by the enormity of Morton's
genius, as well as the skill and sen-
Check No. 58 on Reader Service Cord
58
sitivity of the Victor engineers in
handling these transfers. It has been
28 years since Morton left us, but
thanks to the creative and responsible use of its archives, RCA has
kept the recorded legacy of this artist available to the public. And it
has done so with scrupulous concern for extracting all of the music
from the old 78 grooves while leaving out the bulk of objectionable
hissing, ticking, and popping.
For this, the fourth in its Vintage
series of Morton reissues, producer
Mike Lipskin has selected nine numbers from Morton's last two sessions
for Victor in 1939. On the first of
those two occasions, Morton had selected a band consisting of Sidney
de Paris, trumpet; Claude Jones,
trombone; Sidney Bechet, soprano
sax; Albert Nicholas, clarinet;
Happy Cauldwell, tenor sax; Lawrence Lucie, guitar; Wellman Braud,
bass; and Zutty Singleton, drums.
The second session had much the
same line-up, except that Bechet
did not participate, and Fred Robinson replaced Jones on trombone.
Morton had a special ability for selecting both exceptionally able performers and men who could adapt
their styles to his requirements. No
matter who played on a Morton session, the music that resulted had
that special swagger that was a
Morton hallmark, and there was always an excitement and immediacy
both in the playing of Morton and
in that of his collaborators.
Of particular interest are the recordings of "High Society," with
Bechet and Nicholas competing in
the famous solo spot; "Oh, Didn't
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
MAY 1969
He Ramble," the traditional number for New Orleans bands on their
way back to town following a funeral; and Morton's nostalgic vocal
on his own "I Thought I Heard
Buddy Bolden Say." In addition to
the 1939 -session recordings, this
new reissue contains some of the
trios that Morton waxed in 1929
with Barney Bigard, clarinet, and
Zutty Singleton, drums: Morton's
"King Porter Stomp"; a piano solo
taken from one of the Chamber
Music Society of Lower Basin
Street's NBC broadcasts in 1940;
and a recording of Morton at the
piano in a waxing of "New Crawley Blues" by Wilton Crawley and
the Washboard Rhythm Kings.
Of course, these performances
don't sound like the very best of the
new recordings, but it is absolutely
amazing how good they do sound,
and that sound is enhanced by the
excitement that runs through these
great performances. Once one adjusts one's listening attitude to the
initial sound quality, there is little,
if any, awareness that one isn't listening to fresh, new recordings.
jelly Roll Morton:
I
Thought
I
Heard
Buddy Bolden Say
RCA Victor Mono LPV-559
Performance: A+
Sound:
A-
Urbie Green: 21 Trombones, Rock, Blues,
Jazz, Vol. 2
Project 3 Stereo PR 5024SD
The evolution of a better turntable
The New Sony PS-1800 playback system
has something missing. It also has several
things not found in other turntables. And
therein lies the story of its superior performance.
What's missing? Sony has done away
with the mechanical linkages between
arm and turntable required in the automatic shutoff systems of all other record
playing instruments. To achieve this, Sony
developed a completely new kind of solid
state device, the SONY Magnetodiode
(SMD). It replaces the troublesome mechanical linkages and eliminates any chance
of drag in the tonearm's motion across
the record.
What does the PS -1800 have that other
turntables don't?
The convenience of automatic shutoff
after record is played. A servo -controlled
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cisely the correct speed. A DC motor that
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What does this all mean to you? A
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The new Sony PS -1800 playback system
-turntable, tonearm, oil -finish walnut
base, dust cover. Under $200. Evolution?
It's a revolution. Sony Corporation of
America, 47-47 Van Dam Street, Long
Island City, New York 11101.
Enoch Light's ability to come up with
new sonic surprises has earned him a
special position in the ranks of record
impresarios. Probably one of his most
unusual innovations was bringing together 21 of the country's finest slide horn virtuosos. Headed by Urbie Green,
a young veteran who seems equal to the
most rigorous demands, and backed by
a batch of colorful rhythm and percussion effects, these trombonists stood
the public on its collective ear in
their first set of pop numbers. The success of that first platter has resulted
in a second, even finer effort. We still
have the rare, dark brooding sound of
all those trombones, but now we also
have some music that makes the group
catch fire. Be sure to catch their waxings of Perdido, I Got a Right to Sing
the Blues, and their adaptation of
Flight of the Bumble Bee.
Performance: B+
Sound: A4-
SONMS-1800
PLAYBACK SYSTEM
59
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It costs a few pennies more.
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remember, Sony professional -quality recording
tape is made by the world's
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Light
Listening
SHERWOOD L WEINGARTEN
A Thrush for All Seasons
A husky quasi -whisper sneaks from
the speakers, smoothly changes to a
semi -boisterous trill, then switches to
a gossamer warble. Barbra Streisand,
right? Wrong!
Well, half -wrong. It's Roslyn Kind,
Barbra's half-sister, who has parlayed
the partial kinship and a total talent
into a winning ticket to instant stardom. The younger thrush, a barely -18
hazel -eyed brunette, seems to have
everything Funny Girl has -with the
exception of the need for a nose job,
and the addition of an appeal to the
Shaggy Set.
GIVE ME YOU (RCA Victor, LSP4138) , her initial recording, quickly
shows by its range that the singer
seeks no narrow bag into which she can
artistically crawl. "It Was Only a
Dream," for instance, is sung in a
glossy soul style, supported by an easy
Latin beat and a chorus. "I Own the
World," though, is a Broadway -type
Streisand presentation without Roslyn
resorting to the Ethel Merman -like bellowing Barbra occasionally enjoys..
And "A Modern Version of Love," a
tricky melodic composition, delves into
country music midway (and is somewhat marred in the process). "The
Shape of Things to Come," the only
track of the 11 aimed directly at electronics -crazed youngsters, finds Roslyn
slipping into Judy Collins contemporary art garb, while "Summer Tree"
offers extra Kind-ness as the vocalist
harmonizes with herself via overdub-
bing.
You
never heard it so good.
+1965 SUFERSCOPE. INC.
SNY®
Not unlike Barbra, Roslyn seduces a
song, squeezing the meaning from lyrics, caressing the nuances, insisting the
melody be branded by the white heat
of her intensity. Vocal phrasing of the
sisters is similar, especially on ballads
such as "Who Am I?" and the title
tune. A nonsuspecting listener would
mistake one for the other. Yet when
the tempo builds, and the pop emphasis
is introduced by arranger -conductor
Lee Holdridge, the differences are as
distinct as the stereo separation on
.. Dream." Only two cuts fail: "Can
I Stop the Rain" is over -orchestrated
and ends as if no one were sure any
grooves were left; "If You Must Leave
My Life," a Jim Webb composition, is
merely bland.
Roslyn Kind, whose enunciation
equals that of Lena Horne, created a
mild sensation on a recent Ed Sullivan
videoptic extravaganza. She was rapidly signed for a reprise. Clearly, the
teenager's star is rising like a Saturn
booster. She deserves it, for she offers
a Voice, not an echo.
*
*
*
If singer Mel Torme is the Velvet
Fog, troubadour Rod McKuen is the
Burlap Mist. McKuen, whose pen usually intertwines a love of nature and
a zest for life, somehow managed the
improbable-being both a best-selling
poet and an anti-hero for the Don't Trust -Anyone -Over -30 crowd. But now
the minstrel, approaching 40, is trying
the impossible-aiming his sandpaper textured tonsils toward those who prefer Lawrence Welk over Lawrence Ferlinghetti.
BITS AND PIECES (Decca, DL 75078) is likely to satisfy no one.
Youngsters will dislike the dilution of
the folk -oriented melodies; oldsters will
object to the hodge-podge character of
the LP, and to a non -singer vocalizing;
sound addicts will shun the almost
stereo -less stereo; McKuen buffs will
fume because he renders only two of
his own compositions. "Hi-Lili, Hi -Lo"
seems to be the only track that is totally pleasing to the ear, perhaps because of the breezy woodwind riffs that
give it color.
*
*
*
Spurred by Mideast tensions, manufacturers have pressed Israeli groups
and songs. The unfortunate result is an
avalanche of mediocrity. One exception
is JEWISH RHAPSODIES FOR
THOSE IN LOVE (Bravo, B-35502),
SUPERSCOPE®
Sun Valley, California 91352
Check No. 60 on Reader Service Card
60
AUDIO
MAY 1969
a disc arranged by Pete King for an
anonymous studio ensemble called the
Israeli Strings.
The dozen melodies by the aggregation offer half an hour of relaxed, cotton -candy listening for audiophiles who
choose to pay attention; for those who
prefer Muzak mellowness, orchestration easily can be subordinated by conversation; for those with an insatiable
thirst for good sound, enjoyment will
be ensured by a graceful separation
that avoids the gimmicky ping-pong effect. The strings, naturally, carry most
of the burden. But woodwinds-particularly flute and oboe-and piano solo
often contribute heavily.
The package dips into Broadway for
"Sunrise, Sunset" (from "Fiddler on
the Roof") and "Milk and Honey." It
borrows from Hollywood ("The Exodus
Song") and Tin Pan Alley ("Bei Mir
Bist Du Schön"). And it leans on Al
Jolson, for "Anniversary Song," and
tradition, for "My Yiddishe Momme."
For the most part, the LP is a winner in the softness sweepstakes. Only
"Milk and Honey" gets at all bouncy.
*
*
*
...to the finest stereo cartridge
*
The trouble with William Basie is
that he reached the top and had nowhere to go. HOW ABOUT THIS
(Paramount, PAS -500001) contains a
glossy, ultra -commercial mixture totally lacking in innovations. The Count,
in a half-jazz/half-pop bag, is stuck in
a groove instead of being groovy.
Even the addition of Kay Starr's
vocals (the two stars are paired for the
first time) don't help, for she never
seems quite sure whether she's a blues
singer or someone trying to hit high
C -note on the cash register. She also
errs in trying to re -interpret songs too
well associated with others (such as
Billie Holliday's "God Bless the
Æ
Child") .
-
-
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*
Jackie Gleason has become an American mirror image of Mantovani, turnout one velvety LP after another. THE
BEST OF JACKIE GLEASON, Vol. 2
(Capitol, SKAO-146) is the latest compendium of romantic sweets from the
triple -threat man (humor, music, and
booze, in any order you choose).
Bobby Hackett's trumpet and Tony
Mottola's guitar are the real diamonds
of the lush orchestra, although Gleason made sure to flavor his melodies
with an occasional touch of artistry
from oboe, trombone, flute, and piano.
Best tunes are "My Funny Valentine,"
"I Got It Bad and That Ain't Good"
and "It Had to Be You."
*
STEP UP
61 on
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61
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Stereo Corp. of America, 2122 Utica Avenue, Brooklyn, New York 11234.
MUSIC LOVERS, background music, continuous, uninterrupted, from your FM
radio, using new inexpensive adaptor. Free
literature. R. Clifton, 11500-E N.W. 7th
Ave., Miami, Fla. 33168.
HARTLEY Speakers now available in Tokyo,
Hong Kong, Manila, Noumea, Johannesburg. Hartley Concertmasters on demonstration in Los Angeles and Daly City,
Calif.; Albuquerque, N. M.; Logan, Utah;
Holland, Mich.; Newtown Square, Pa.;
Miami, Fla.; West Orange, N. J.; and Port
Jervis, N. Y. Write Hartley Products Corp.,
Box 68A, Ho-Ho-Kus, N. J. 07423.
GRAPHIC CONTROLLER, Serial No.
1969. New-May 1968, Never Used. $300
complete with manual and walnut sides.
J. Bongiorno, 48 Washington, Westfield,
N. Y.
JBL
TAPE RECORDER SALE.
40 PAGE CATALOG offers hundreds
of recordings of rare Renaissance, Baroque
and Classical music. Some records priced
as low as $1.00 each! All late recordings in
stereo only. MHS Records, Box 932 -AM,
New York, New York 10023:
OLDIES-45 RPM. Original hits. Over 3000
available. Catalog 250. C & S Record Sales,
Box 197, Wampsville, N. Y. 13163.
ACOUSTIC RESEARCH products now available to overseas personnel, diplomats, and
citizens of foreign countries. Write for
full product and dealer information. AR
International, Dept. SR, 24 Thorndike St.,
Cambridge, Mass. 02141.
DISC RECORDING EQUIPMENT: Complete mono and stereo cutting systems
featuring rebuilt Scully, Neumann, Van
Eps, and Fairchild lathes and new W.A.L.
amplifiers. Priced from $2500.00. Wiegand
Audio Laboratories, 3402 Windsor Road,
Wall, N.
J.
0719.
FOR SALE: Marantz 15, $300.00 and Marantz 7T $260.00 with oil cab. Paul Mascetta, 2837 Decatur Ave., Bx. 10458, N. Y.
SCULLY Professional Tape Recorders, from
to 24 tracks, complete recording studio
packages designed to order featuring
W.A.L. console systems and other leading professional audio products. Phone
201-681-6443. Wiegand Audio Laboratories, 3402 Windsor Road, Wall, N. J.
07719.
1
Brand new na-
tionally -advertised brands, $10 above cost.
Amazing discounts on stereo components.
Arkay Electronics, 1028-H Commonwealth
Avenue, Boston, Mass. 02215.
NEW UHER 4000L recorder, Nicads, charger, Akustomat, attache case, etc. Make
offer. Jack Trimble, 3817 Ronning Drive,
Sioux Falls, So. Dakota 57103.
RECORDS, TAPES, MOVIES, BOOKS.
Unlimited selection. Send 250 for catalogs.
Murphy's Records, Route 1, Box 600A,
LaPlace, Louisiana 70068.
CATALOGS, Broadcasts, soundtracks,
Personalities of Thirties, Forties. Box 225, New
York, N. Y. 10028.
64
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
MAY 1969
A
FOR SALE
EQUIPMENT WANTED
McINTOSH/BOZAK Bi -amp system. MR -71,
C-24, two 2505's, two B -4000's, Bozak electronic crossover. Crown SX-724, Dual 1019
with Shure type II. Individual cabinets.
Absolute mint condition. 1 year old.
$2800.00. Will not argue. 213 Merrill Dr.,
Milton, Fla. 32570.
CASH FOR YOUR unwanted LP's and prerecorded tapes. Record House, Hillburn,
New York 10931.
DYNA 120 and PAT -4. Both perfect condition. $200. L. Drasin, 139-80 85 Drive, Ja-
HEATH IB-28, Tom Groom, Box 766, Murfreesboro, Tenn. 37130.
Complete Audio Reference
Library in
WANTED: V -Disc. Stephen Bedwell, 5850
Spring Garden Road, Halifax, Nova Scotia,
Canada.
I
1
a Single Volume!
(cw
1r,fla'*
AU
cycLppEplA
maica, N. Y. 11435.
REVOX G36, $350.00. As new (25 hours)
warranty. After 7:00 pm, 609-854-3448.
Barclay, Apt. 408B, Parkview, Collingswood, N. J.
NEUMANN U-67 MICROPHONE, plug-in
power supply, 25 ft. ext. cable. Perfect
condition. $200.00. Edward Lisk, 113 Stanton St., New York City, N.
Y. 10002.
CROWN SX 824 Pro -Deck, 11 months old,
Mint Cond. 212-HO 5-4717.
24-TRACK?-Modular tape recording amplifier with bias and erase buffer. Dop
Audio, 601 S. Vermont, Los Angeles, Calif.
90005 (213) DU 8-7104.
AUDIO 48-67 $3/year.
E.
Fewell, 5323 Cic-
ero, Mesa, Ariz'
ORGAN OWNERS, BUILDERS & TECHNICIANS. We sell new and used consoles,
electronic kits, manuals, pedals, speakers,
reverbs and percussions. Buy direct and
save. Write for catalog. Newport Organs,
300 W. Coast Highway, Suite D, Newport
Beach, Calif. 92660.
AMPEX AG -500-2 in case, 71/2 and 15 fps,
only a month old, $1275. AMPEX F-4470
in case with amplifiers and speakers, 33/4
and 71/2 ips, excellent condition. ITT stereo
multiplex AM -FM tuner-amp, excellent
condition, $125.00. REK-O-KUT 16 -inch
turntable, 33 and 78 speeds, hysteresis
motor, in excellent condition, $75.00. AR
turntable like new, with ADC cartridge,
$65.00. KLH-6 speaker, one month old,
$90.00. All f.o.b. Associated, Box 632,
Beverly Hills, Calif. 90210.
from Japan-tape
recorders, speakers, amplifiers, turntables,
and accessories. Free catalog and quotations. Playboy Shop, Box 221, Agana,
Guam.
STEREO COMPONENTS
KLH MODEL 1, Walnut. With or without
tweeter. Fred Brandt, 8201 Garland Ave.,
Takoma Park, Md. 20012.
STEREO TAPE RENTALS for the discriminating listener. Free catalog. Gold Coast
Tape Library, Box 2262, Palm Village, Hialeah, Fla. 33012.
McINTOSH 2505. John Pasiecznick, 52
Crest, Murray Hill, N. J. 07974.
-V MARQUIS or Aristocrat enclosure. Factory assembled. Walnut. A-1. WiII pay $100
E
y.wa4lN
t.ed
plus express. SP4-Jay E. Smaltz, HHC, 1st
Bn, 69th Armor, APO San Francisco 96262.
HOBBYIST will purchase detailed plans
and schematics for transistorized recording console and accessories. Describe and
quote price. Lane Cameron, 1801 S. Dixie
Hwy. #80, Pompano Beach, Fla. 33060.
WANTED: Audio, Radio Electronics, Electronics World, Broadcast
Engineering, B-M/E, other volumes preferred, recent and early. Send dates, condition, price. Lowery, 1950 Preston, Los
Angeles, Calif. 90026.
NEW
Audio Cyclopedia
by Dr. HOWARD M. TREMANIE
Greatest Single Compendium of
Information on Every Phase of Audio
BACK ISSUES
WANTED: Used Marantz model 18, Sony
6060F or TA -1120 and ST-5000FW.Send
condition and price. P. Lin, 5459 Cornell,
Chicago, III. 60615.
EVEREST 2 -track classical commercially recorded tapes. Must be in facty 2-tr printed
boxes. Will pay up to $8 per tape if in
mint condtn. Send list H. A. Slataper, Jr.,
5902 Telephone Rd., Houston, Tex. 77017.
KENWOOD amplifiers and speakers-discount prices-free catalog and quotations.
Playboy Shop, Box 221, Agana, Guam.
SITUATION WANTED
WOULD LIKE TO WORK
tributor assistant. Call
as a
Just Out! The single book offering the most
comprehensive information on every aspect
of the audio art. Fully updated to include
latest developments, right down to the newest solid-state and integrated circuits. Gives
you concise, accurate explanations of all
subjects in the fields of acoustics, recording,
and reproduction ... each subject instantly
located by a unique index and reference
system.
25 Sections! Contents include: basic principles of sound; acoustics, studio techniques
and equipment; constant -speed devices, motors, and generators; microphones; attenua tors; equalizers; wave filters; transformers
and coils; sound mixers; VU meters; tubes,
transistors, and diodes; amplifiers; disc recording; cutting heads; recording and reproducing styli; pickups; magnetic recording;
optical film recording; motion picture projection equipment; speakers, enclosures, and
headphones; power supplies; test equipment;
audio -frequency measurements; installation
techniques; special charts and tables. This
is the indispensable, complete reference book
for the audiophile.
PRE -PUBLICATION OFFERI Available for limited time only at the special pre -publication
price of only $26.95.
Order today from your Sams
Distributor or mall coupon.
Pre -publication price good
only untilJuly 1,1969.Thereafter, price will be $29.95.
record dis-
KNOWLEDGE
COMPOAGGRESSIVE,
NENTS, music. Experienced sales manage-
buying, merchandising. Seeking
major company, major product, for major
potential. Box AMA9-1.
ment,
Over 1300 fact -packed pages
Covers more than 3400 topics
Over 1600 illustrations
Completely updated content
(215) KI 6-0220.
MANUFACTURING MANAGER, business
and technical experience in audio amplification and devices, sales and profit oriented, engineering design and evaluation,
styling, organization, motivation, cost controls, sales promotion, administration and
controls, industrial engineering, 45, Energetic, E. E. Graduate, self starter, can travel,
P. O. Box 155, Bricktown, N. J. 08723.
UPDATED 2ND EDITION
SPECIAL SAVINGS ORDER FORM
t
Howard W. Sams
Co., Inc. Dept. AU -5
4300 W. 62nd St., Indianapolis, Ind. 46268
Enclosed is $
Please send me
copies of the AUDIO CYCLOPEDIA at the special
pre -publication price of $26.95 each. I understand
books are returnable within 10 days for full refund.
Pre-publtcetion price of $26.96 to good anal
Ja17 1. 1969; thereafter the price will be 129.96.
Name
Address
State
Zip
J
Check No. 65 on Reader Service Card
AUDIO
MAY 1969
65
Stereo
FM
*INDOW
ANTENNA
by
F//VCO
Outperforms any
indoor antenna!
List Price
$16.95
All directional receiving pattern.
Aluminum construction with goldcorodized corrosion -proof finish
on antenna.
Fits horizontally or vertically in
windows up to 42" wide or high.
Extension bars available for larger
windows.
Write for Catalogue 20-462 Dept. AM -5
F/NCO THE FINNEY
COMPANY
34 West Interstate St., Bedford, Ohio 44146
Enjoy Relaxing
Advertising
Index
Background Music at Home
with
Acoustic Research, Inc.
COMMERCIALS!
5
& K Instruments, Inc.
Benjamin Electronic Sound Corp
British Industries Corp.
20
Classified
Crown International
Crown Radio Corp.
64
29
63
Dolby Laboratories, Inc.
25
Dynaco, Inc.
35
B
HO
15
3
Elpa Marketing Industries
Erath, The L. W., Co.
61
Our SCA-1 Decoder makes possible reception of this "private" musical programming,
transmitted by nearly 400 FM stations
around the country. YOUR FM tuner or
receiver can recover this "hidden" music
with the simple addition of an SCA-1.
Hook-up in minutes-full instructions
supplied. SCA-1 is self -powered ... uses all
solid-state circuitry (FET's, IC's, NPN's).
Works with any quality FM Tuner or
49
Receiver.
Finney Company
66
Garrard Sales Company
Gotham Audio Corporation
63
Hi -Fidelity Center
66
JVC America, Inc.
7
Electro -Voice, Inc.
Cover IV,
1
...
3
Send check or m.o. for either
SCA-1 (Wired, ready to use)
$64.50
SCA-1K (Kit, all needed parts)
$49.95
Etched, drilled P.C. Board plus special IC &
full construction plans
$12.50
One year parts guarantee
Prohibited for commercial use
Free Brochure
& SCA Station list
upon request
SCA Services Co.
Check No. 90 on Reader Service Card
Box 601,Port Washington, N.Y. 11050
Check No. 92 on Reader Service Card
¢
Sitarh¢3E
penciLs
J,1 JoWn
Marantz Company
Martin Audio Corp.
McIntosh Laboratory, Inc.
Mikado Electronic Corp.
Nortronics Corp.
Pickering & Co., Inc.
Pioneer Electronic U.S.A. Corp.
/
YOU SAVE MORE
ON HI-FI COMPONENTS
& TAPE RECORDERS
invite your test of our
"We Will Not Be Undersold Policy."
We
15 -day money -back guarantee.
2-yr.
labor
unconditional guarantee parts &
no
charge, at local warranty
station or factory.
Trade-ins-highest allow. Send your list.
Most items shipped promptly from our
$250,000 inventory, fully insured.
Our specialty-APO & Export.
23rd yr. dependable service-world wide.
Rated
service-satisfaction according to
nationwide survey.
Write for Our Price First!
You'll Be Glad You Didl
tl
31
4
a
6
19
47
37
SCA Services
Sams, Howard W., Inc.
Sansui Electronics Corp.
66
65
13
66
62
9
Saxitone
Schirmer, G.
Scott, H. H., Inc.
Cover II
Sherwood Electronics Labs, Inc.
51
Shure Brothers, Inc.
11
Sony Corporation of America
58, 59
Sony/Superscope
17, 33, 60
Stanton Magnetics
Cover III
53
CENTER
he House o1 Low Low
University Sound
52
Wiegand Audio Corp.
23
Check No. 66 on Reader Service Card
challenging opportunity for
growth with a manufacturer of top
quality stereo equipment? Do you
have a working knowledge of
electronic theory? McIntosh Laboratory, Inc. needs an Assistant
Service Manager.
8
Rectilinear Research Corp.
ReVox Corporation
TEAC Corp. of America
'frees-
Do you want
61
HI -FIDELITY
239- V East 149th St.
New York, N.Y. 10451
66
Rabco
43, 45
If you think you may qualify, and
if your future at your present job is
not as bright as you'd like, phone
collect. A. L. Hyle, (607) 723 3512.
ore/co
j CASSETTE
If
RECORDER
for
the
will refund difference within IO da
rchase.
of
our
price
not
NORELCO is
LOWEST we
CASSETTES
LIFETIME GUARANTEE f (Unbreakable Boa)
C-30
s/s Hr. .79 Postage 8% of Total Pur C -60
1
Hr. .99 chase (over $20 we pay)
Catalogs:
C-90 W2 Hr. 1.39 FREE Music
or
C-120 2 Hr. 1.69 4 track open reel
8 track
or -cassettes.
Also blank tape and Recorder discount catalog.
1776 Columbia Rd.. N.W. Wash.. D. C. 20009
-
- -
afförsIE
Check No. 94 on Reader Service Card
AUDIO
MAY 1969
You can tell it's the Opéra at Versailles
when you listen with a Stanton.
The Opéra at Versailles, completed 1770, scene of the first performances of Jean Baptiste Lully's operas and ballets.(Lully was court compoier to Louis XIV.)
The ultimate test of a stereo cartridge isn't the
sound of the music.
It's the sound of the hall.
Many of today's smoother, better -tracking cartridges can
reproduce instrumental and vocal timbres with considerable
naturalism. But something is often missing. That nice, undistorted
sound seems to be coming from the speakers, or from nowhere in
particular, rather than from the concert hall or opera stage.
It's easy to blame the recording, but often it's the cartridge.
The acoustical characteristics that distinguish one hall
from another, or any hall from your listening room, represent the
subtlest frequency and phase components of the recorded waveform. They end up as extremely fine undulations of the record
groove, even finer that the higher harmonics of most instruments.
When a cartridge reproduces these undulations with the
utmost precision, you can hear the specific acoustics of the Opéra
at Versailles, or of any other hall. If it doesn't you can't.
The Stanton does.
srarvror
Stanton
The specifications!' Frequency response from 10 Hz to 10kHz, ±1/2 dB.
From 10kHz to 20kHz, individually calibrated. Nominal output, 0.7rnhr/cm/sec.
Nominal channel separation, 35dB. Load resistance, 47K ohms Cable capacitance,
275 pF. DC resistance, 1K ohms. Inductance, 500mH. Stylus tip, .0002"x .0009"
elliptical. Tracking force, 'Li to 1'/e. gm. Cartridge weight, 5.5 gm. Brush weight
(self-supporting), 1 gm.'Each Stanton 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
cartridge. The 681EE, with elliptical stylus and the "Longhair" brush that clean';
record grooves before they reach the stylus, costs $60. The 681T, identical but
with interchangeable elliptical and conical styli both included, costs $75.
For free literature, write to Stanton Magnetics,Inc., Plainvïew,t.L, N.Y. 11803.
Check No. 103 on Reader Service Card
At last someone
has made. another
PA speaker like the unique,
distortion-free CDP®
There's a good reason why only
Electro -Voice has produced the
compound horn. That reason is U.S.
Patent No. 2,856,467. And though several have tried, there's just no equal
to this ingenious design.
The difference made by a compound
horn is easily heard. Distortion is lower,
particularly at or near full power.
Response is smoother, flatter, with
extended highs for better intelligibility.
And with no peaks in response, the.
chances of feedback are greatly reduced.
This improved performance is
gained at no loss in efficiency. In fact,
in many installations fewer compound
horns are needed to do the same job
as reentrant horns. So, costs are lower,
installation time is shorter, and main-
It had to be us.
tenance is easier.
Until recently, the advantages of
compound design were available only
in the wide-angle CDP (FC100)-the
fiberglass horn that started the trend
to high fidelity response in public
address. Now you can have a choice.
Our newest compound horn is the
round ACI0O horn. It puts more useful
energy on axis than much larger reentrants. And the ACI0O concentrates
its energy with the same high quality
that has made the wide-angle CDP
famous. Smooth response, low distortion, extended highs-all advantages
that every audience will hear and
appreciate, and all exclusive with E -V
compound horn design.
Both the AC1OO and the FC10O
require E -V convertible drivers. And
now there are four from which to
choose. Rated at 30 and 60 watts, with
and without 70.7-volt transformers.
Every driver offers the efficiency of
E-V ceramic magnet design, combined
with utter reliability. Even so, diaphragm assemblies are field replaceable
(after all, accidents will happen).
Find out for yourself how our compound horns can improve your next
sound installation without compound-
ing your problems. For complete
catalog information, write today.
SHOWN ABOVE: Left, 848A 30 watt CDP speaker,
$89.00 list; or FCI00 horn only, $53.50 list for use with
any E-V convertible driver. Right, ACI00 horn only,
$92.00 list. Not illustrated, smaller 847 25 watt CDP
speaker, $59.00 list. Normal trade discounts apply.
high fidelity speakers and systems tuners, amplifiers, receivers public address loudspeakers microphones phonograph needles and cartridges organs space and defense electronics
ELECTRO -VOICE, INC., Dept. 596A,602 Cecil Street, Buchanan, Michigan
Check No. 104 on Reader Service Card
49107teem,
arc®
A SUBSIDIARY OF GULTON INDUSTRIES, INC.

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