Tape Recorders-A View From The Crystal Ball

Tape Recorders-A View From The Crystal Ball
The
Authoritative Magazine About High Fidelity
23602
Tape Recorders-A View From The Crystal Ball
Refacing Tape Recorder Heads
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A
Scott
components
always get
good reviews!
Why?
o
It could be their performance.
It could be their value for the price.
The professional reviewers' findings may be best
summarized by a respected test engineer who said,
"In the nearly twenty years I've been evaluating audio
components, Scott units have consistently met, and in
many cases, substantially exceeded, their published
specs." No one should be surprised at this. Hermon
Scott and his colleagues planned it that way from the
very beginning. Scott components are intentionally
rated conservatively to provide a safety margin, so that,
even with normal tolerances in piece parts and
production techniques, every Scott product shipped will
meet or exceed its published performance claims.
Reviewers have the edge on audiophiles, and even most
dealers, because reviewers get the opportunity to critically
evaluate virtually every product on the market, and
compare it with everything else in its price class. After
they've made a spec -for-spec and feature -for-feature
comparison of everything available, they know which
products represent the best value to the buyer. When a
reviewer says of a Scott product, "This receiver offers an
unexcelled value for the price," the audiophile can
purchase the unit with the certain knowledge that he is
getting his money's worth.
It could be their advanced design features.
When the present Scott line of audio components was
first shown to dealers and the press, a reviewer from a
non -audio-buff magazine commented, "My readers and
I are more interested in what the equipment does than in
how it does it. These Scott components seem to me to
have all the controls and convenience features the
serious listener needs." That, too, should be no surprise,
for H. H. Scott is traditionally the first to use advanced
design concepts in circuitry, function and appearance,
but only where such advances contribute demonstrably
to user convenience and satisfaction.
Professional audio equipment reviewers like H. H. Scott
components for their performance, advanced design
features and value for the price. But aren't these the very
qualities you look for when you purchase an audio
component or system? You'll find these qualities in every
Scott tuner, amplifier, receiver and speaker system now
on display at your Scott dealer's.
cuiscorrewlnnovalion
H.H. Scott, Inc.,
111
Isdition
Powdermill Road, Maynard, Mass. 01754
Check No. 100 on Reader Service Card
h
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TEAC AS -100 and
AT-100 expand your
system
componentially
Just as we make definitive Dolby* equipment at TEAC, we make consummate
components. They are designed to be the match of our professional -quality tape decks in
every detail. So they must do more qua components than merely frequency -demodulate
and amplify. And yet they must be sensibly priced so they don't make you ear -rich
and pocket -poor. Add either or both to your system and the total improvement is infinitely
more than a simple sum.
Take the AT -100 Stereo FM Tuner, for example. It's equipped with a new muting circuit
to eliminate inter -station noise, and unique multiplex channel -separation circuitry for
distortion -free reception, even in fringe areas.
Similary, the AS -100 Integrated Stereo Amplifier combines the most desirable features
and specs of a preamplifier/amplifier control center. Direct -coupled differential amplifiers
inspired by computer and instrumentation systems. Electronic protective circuits on outputs
to prevent damage from open or short circuit speaker conditions. Front panel tape deck
input jacks, headphone jack and switch selection of two speaker pairs and tape/source
monitoring. Its time to take a quantum leap with TEAC tape components.
For name of your local TEAC component specialist, write TEAC Corporation of America,
7733 Telegraph Road, Montebello, Calif. 90640.
TEAC©
TEAC Corporation of America, 7733 Telegraph Road, Montebello, California 90640
TEAC EUROPE N.V., Kabelweg 45-47, Amsterdam-W.2, Holland
TEAC Corporation, 1-8-1 Nishi-shinjuku, Shinjuku-ku, Tokyo, Japan
In Canada: White Electronic Development Corp., Ltd., Toronto
Check No. 29 on Reader Service Card
'Dolby
is a
trademark of Dolby Laboratories Inc.
AT -1 00
FM Stereo Tuner
Sensitivity
2.0 µV UHF)
Selectivity
Better than 65 dB
(± 400 KF'z)
Harmonic Distortion
Below 0.5% (1,000 Hz,
100% modulation)
APP,"
SPERM FM TUNER
AS -100
Integrated
Stereo Amplifier
A9 300
tNTECiRACEU AMPLIFIER
Fated Power
60 W (both channels
operated THD 0.2%,
8 ohms load)
Freq. Response
5-200,000 Hz +0 -2 oB
(powe- amp)
IM
Distortion
Below 0.2% rated power
www.americanradiohistory.com
AmericanRadioHistory.Com
lifetime
rantee
re-J111
AUDIO
APRIL 1972
Successor to RAD10 , Est.1911
Vol. 56, No.
4
FEATURE ARTICLES
12
16
Why is Sharpe
the only one to
guarantee
stereophones
s long as you live?
No one else does.
But we have good
reasons why rrve give a
lifetime guarantee on
our Model 773 ... and
full year guarantees
on all our others.
We build in the highest
quality that turns out
a near -zero detect
record.
The Sharpe Stereophone
you buy has been
through a testing
ordeal that would
reject most other headphones on the market.
It's rare for a' Sharpe
Stereophone to
come back to us.
That's why we can
pass on to you our savings
in repairs in the
form of absolute
guarantees. Inspect
this quality of Sharpe
Stereophones at your
nearest dealer. You'll
know what we mean.
For his name and
literature, check
the reader
service
card.
20
22
24
32
Lirpa Matrix System Unveiled
Choosing A Tape Recorder
Refacing Tape Recorder Heads
Mathematics 4 Beginners, Pt. IV
Microphones-Quo Vadis?
Activating Your Loudspeaker Crossover
36 From the People Who Brought You Franz Liszt?
40 Tape Recorders-A view from the Crystal Ball
62 Corporate Block Unblocked
BUYERS GUIDE TO OPEN -REEL TAPE RECORDERS
46 Directory of Open-Reel Tape Recorders
EQUIPMENT PROFILES
50
52
54
TEAC Cassette Deck
Marantz Speaker System
Telex 8 -track Cartridge Player
AUDIO
DIVISION
SCINTREX INC.
Tonawanda,
N. Y.
-
4150
Export Agents
ELPA MARKETING
INDUSTRIES, INC.
New Hyde Park.
N
Y
11040
Model A -24
Imperial VI
Model 48-H
RECORD AND TAPE REVIEWS
56
58
61
66
68
70
Solti's Magic Flute
Classical Record Reviews
Canby's Capsules
Weingarten Looks At ..
Tape Reviews
Jazz & Blues
Richard Freed
Edward Tatnall Canby
Edward Tatnall Canby
Sherwood L. Weingarten
Bert Whyte
Martha Sanders Gilmore
AUDIO IN GENERAL
4
4
6
8
10
71
74
Coming In May
Audioclinic
Tape Guide
What's New In Audio
Behind The Scenes
Classified Advertising
Advertising Index
Joseph Giovanelli
Herman Burstein
Bert Whyte
EDITOR George W. Tillett
PUBLISHER Jay. L. Butler
ASSOCIATE EDITOR Edward Tatnall Canby
MARKETING DIRECTOR Sanford L. Cahn
ASSISTANT EDITOR Eugene Pitts
COVER DESIGN John Kwasizur
DESIGNER Rowena Kendall
SUBSCRIPTION MANAGER Jean Davis
ADVERTISING PRODUCTION Sharon Mancini
CONTRIBUTING EDITORS: Herman Burstein,
Giovanelli, C. G. McProud, H. E. Maynard,
SHARPE
H. W. Hellyer
William B. Fraser
Norman H. Crowhurst
James H. Kogen
Michael W. King
George W. Tillett
Herman Burstein
Edward Tatnall Canby
Leonard Feldman, Richard Freed, Joseph
Alex Rosner, S. L. Weingarten, Bert Whyte
AUDIO (title registered U. S. Pat. Off.) is published by North American Publishing Co., I. J. Borowsky. President; Frank
Nemeyer and Roger Damio, Vice Presidents; R. Kenneth Baxter, Vice President/Production; Nate Rosenblatt, Promotion
Director; Mary Claffey, Circulation Director.
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 Columbus, Ohio. All rights reserved. Entire contents copyrighted 1972 by North American Publishing Co.
Second class postage paid at Philadelphia, Pa., and additional mailing office.
REGIONAL SALES OFFICES: Jay L. Butler, Publisher, and Sanford L. Cahn. Marketing Director, 41 East 42nd St., New
York, N.Y. 10017, telephone (212) 687-8924.
Jay Martin, 15010 Ventura Blvd., Sherman Oaks, Calif. 91403, telephone (213) 981-7852.
REPRESENTATIVES. United Kingdom: Overseas Newspapers (Agencies) Limited, Cromwell House, Fulwood Place, London
W.C.I. telephone 01-242 0661, cables, WESNEWS, London PS4.
Continental Europe: John Ashcraft, 12 Bear St., Leicester Square. London W.C. 2, telephone 930.0525. For Benelux and
Germany. W. J. M. Saunders, Mgr., Herengracht 365. Amsterdam, Holland, telephone 24.09.08.
Japan: Japan Printing News Co., Ltd., No. 13, 2 Chome Ginza Higasi, Chuo-ku, Tokyo, telephone 541-5795.
AUDIO Editorial and Publishing Offices, 134 N. 13th St. Philadelphia, Penna. 19107
Postmaster: Send Form 3579 to the above address
Check Nc. 2 on Reader Service Card
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11
test reports on the Zero 100
by the industry's leading reviewers
first
Brief excerpts reprinted below. Let us send you the full reports.
HIGH
FIDELITY
AUDIO
Sept. 1971
Altogether, this new arm strikes us as an
excellent piece of engineering; it probably is the best arm yet offered as an
integral part of an automatic player. D
Operation is simple, quiet, and reliable.
All told, we feel that Garrard has come
up with a real winner in the Zero 100.
Even without the tangent -tracking feature
of the arm, this would be an excellent
machine at a competitive price. With the
novel (and effective) arm, the Zero 100
becomes a very desirable "superchanger"
with, of course, manual options.
August, 1971
Reproduction quality was excellent with
no detectable wow, flutter or rumble
under stringent listening conditions. End
of side distortion, which is always a possibility with pivoted arms, was virtually
absent, due no doubt to the tangential
tracking arm.
HI-FI
ßrr:,r.i,nr.-i
Stereo Review
July, 1971
The Zero -100 performed just about as we
Indeed, everything worked smoothly,
expected after reading the specifications.
Wow measured .08 per cent
that is in
the band from 0.5 to 6 Hz. Flutter, in the
band from 6 to 250 Hz, measured .03 per
cent, both of which are excellent. D Thus,
the Garrard Zero 100 is certainly the
finest in a long line of automatic turntables which have been around for over
50 years. D We think you will like it.
quietly, and just as it was meant to. If
there were any "bugs" in the Zero 100,
we didn't find them. D Garrard's Zero
100, in basic performance, easily ranks
with the finest automatic turntables on
the market. Its novel arm which really
works as claimed and its other unique
design features suggest that a great deal
of development time, plus sheer imagination, went into its creation. In our view,
the results were well worth the effort.
-
Popular Electronics
The (;RAMOPHONE
July, .1971
-
-
August, 1971
Our lab measurements essentially confirmed the claims made by Garrard for
the Zero 100. We used a special protractor with an angular resolution of about
0.5°, and the observed tracking error was
always less than this detectable amount.
The tracking force calibration was accurate, within 0.1 gram over its full range.
The Garrard Zero 100 operated smoothly
and without any mechanical "bug
Sept. 16, 1971
This unit has every imaginable gadget
and gewgaw one might possibly desire,
and it works. And considering how much
it does, and how well it does it, at 190
bucks it doesn't even seem expensive.
The changer has so much in it that an
analysis Of its innards is almost a case
study in record player design.
Fall, 1971
One could go on cataloguing the virtues
of the Zero 100 indefinitely.
I
I
'
I
I
1
1
I
For 8 -page test reports booklet and a 12 -page
brochure on the Zero 100 and the entire Garrard
series mail to British Industries Company,
Dept. D-12, Westbury, N.Y. 11590.
Name
Address
I
I
City
Zip_
A genuine step upward in automatic turntables
;G1 CirI_1;
"r4
The only automatic turntable with Zero Tracking Er -or
Mfg. by Flessey Ltd.
Dist. by British Industries Co.
s
$1895°
less base and cartridge
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oWó9
Audioclinic
May
The "open aire" principle in
headphone design-F. Warning
Letter-Don Aldous
* London
Equipment Reviews Include:
*Miracord 50H Il Record Changer
*Heathkit Digital FM Tuner
`
*
Men of Hi-Fi-Gerry Orbach,
Tom Lott, and Harry Maynard
discuss four -channel systems.
Late Flash!
Due to tremendous interest,
the Midwest Acoustic Conference will be held in a larger
hall-at the National College of
Illinois.
Evanston,
Education,
The date remains unchanged,
April 15th.
r°
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Hum in a Turntable
Q. I am having trouble with an excess
of hum in my turntable. I am certain
that the hum comes from the turntable
because it is present only when the
turntable motor is on, vanishing when
the motor is off. The hum is not present
when playing tapes or listening to the
tuner.
I checked the ground on my turntable.
The hum is about the same whether the
ground is connected or not. I tried
grounding the amplifier to things in the
room, like the radiator, the a.c. outlet
box, etc. This did not help either.
The position of the cartridge relative
to the record does influence the hum.
The further in the cartridge is moved
toward the center of the record, the
louder the hum becomes.
Any advice you can give me would
be appreciated.-Harry Hastings, Pullman, Wash.
A. The fact that the amount of hum
varies with the position of the tonearm
indicates that the problem is the result
of induction from the windings of the
motor into the pickup. Either the
shielding of the pickup is defective or
the shielding in your particular model
is insufficient when used with your
turntable. If you can obtain some magnetic shielding material, wrap it around
the cartridge, leaving room for the
stylus and to be sure that the shielding
material does not come into contact
with the record. I have done this. It
did help to some extent. It did not
eliminate the problem entirely, however.
I would say that you need to try
another cartridge, with the understanding that, if the hum does not cease,
you can return the cartridge to your
dealer and try a different one. I believe
there is no other solution to your problem.
Insufficient Loudspeaker Output
two rather
inexpensive outdoor speakers for use in
my music system. They are identified as
Wald Sound T-3 Tune Toater.
I am using them in conjunction with
a Fisher 500TX stereo Receiver. The
speakers are located approximately 40
to 50 feet from the amplifier. They are
equipped with self-contained volume
Q.
About The Cover: The demise
of open -reel tape recorders has
been predicted many times-but
they are still very much alive as
our Directory shows. This brings
to mind Mark Twain's comment
on reading his obituary. "The
reports of my death are greatly
exaggerated...
I recently purchased
controls.
My problem is that the volume I get
from these speakers is virtually nothing
compared to the volume I get from the
Joseph Giovanelli
indoor speakers at the same amplifier
volume control setting. Can you shed
some light on what my problem might
be?-Thomas A. Mantini, Havertown,
Pa.
A. As I have no data about your outdoor speakers, I cannot discuss them
with certain knowledge. If you have
literature which was supplied with
them, check it to see if perhaps their
impedance is something like 500 ohms
or perhaps designated as "70 volts."
If this is true, you must remove the
matching transformers which are inside
the speakers. Further, you must then
hope that the basic impedance of the
speakers is at least 8 ohms so that they
will not load down the amplifier when
used in conjunction with the main
speakers in your listening room.
Assuming that the speakers are of
the correct impedance, I suggest that
you use No. 16 gauge zip cord as the
interconnecting cable between them
and your amplifier. That will keep
down losses to an absolute minimum.
You indicated that you have a distance of 40 to 50 feet between amplifier and speakers. Sometimes this distance is longer as regards the amount
of interconnecting line required. You
know what happens. The line must go
around moldings and follow baseboards. That can add quite a few feet.
Therefore, if it happens that you have
50 to 60 feet of actual interconnecting
line, use No. 14 gauge zip cord.
You should check to see whether
there are other terminals on the rear
of the -speaker. Some speakers provide
for various arrangements of jumpers
which must be connected or disconnected depending on whether you are
going to use internal volume controls,
etc.
I am not sure just how loud your
outdoor speakers do play. More volume
will be required when speakers are
located outdoors than would be true
when they are located indoors. Further-
more, if these speakers are inefficient,
and if the indoor speakers are efficient, the indoor speakers will definitely sound louder than the outdoor
speakers, even when nothing is wrong
with them.
If you have a problem or question on
audio, write to Mr. Joseph Giovanelli at
Street,
134
North Thirteenth
AUDIO,
19107. All letters are
Pa.
Philadelphia,
answered. Please enclose a stamped selfaddressed envelope.
AUDIO
4
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OUR 25th YEAR
APRIL 1972
Introducing
four completely new
stieren receivers with more
of everything.
Sooner or later other stereo receivers
will strive for the total combination of
power, performance, features, precision and iersati ity incorporated irtc
pioneer's totally new SX-828 SX-727,
EX -626
aid SX-525.
Why wei
Each of these except Dnal
receivers delñ.ers the most watts of
power for the money. You can Drove it
b, making yoar own comparisors.
SX-828, 270 watts IHF; SX-727, 195
watts IHF; SX-626, 110 watts IHF;
3X-525, 72 watts IHF. The use of
?
Fioneer has mo-e cf everything now.
88
I
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.
.
88
.t
92
94
91
98
'72
100
104
t(18
106
t
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90
94
14
98
;92
MC
Mb
104
direct -coup ed amplifiers and twin
power supplies i the -op two models
further enhancepe-fo-man e and
responses, while rr ninizing
distortion.
The crowded F Vic al and weak
stations offer nc c -allenge to this new
and advanced FE- and IC circuitry.
Every staticn scur is as though it's
just arourc the z.orner. Fur:her, your
speakers are protested against
damaçe and DC leakage (a cause of
distortion) by the ingeniously new an,d
exclusive PicnEerelectronic trigger
relaj system desiçnec for the
SX-828 anc SX-72=.
-The h çnest degree of versat lily is
ach eed wits a wide range of features, includ nc F"./1 ruling, loudness
contour, mode guts, click-stop tone
contrcls, te.ning meters, ultra wide FM
dial, plus a full complemert of cone
nections fcr turnt_bles, tape decks,
head_hones, rr crepbones, speakersanc even --channel, when you re
ready.
Ask ycar P oreer dealer to cemonstrate each of -here rew models.
Rega-dless whic- new Pioneer
receiver yriu fhalty select, you're
assured it represnts the'inest at its
price SX-:328 S.129.95: SX-7j7
$3L9.35; SX-623 $279.95; S}:-525
$239.95. Prices i-clLde walnu:
cab -etc.
U.S. Fione_rElectronics Corp.
138
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www.americanradiohistory.com
AmericanRadioHistory.Com
S. H.
PARKER CC_-ONTARIC
want someth ng better
Tape Guide
Make sure
Herman Burstein
to attend...
Trouble with
S -O -S
at my expense,
that the well -advertised features of
sound -on -sound and sound-with -sound
are impossible to achieve. Because of
the physical distance between the, record
and playback heads, there will always
he approximately a one second delay
between the two signals being recorded.
Therefore the signals cannot be synchronized. Does this difficulty exist in all
moderately priced decks? If so, can
synchronization of several musical parts
be accomplished with a mixer and two
tape decks?-Herbert N. Foerstel, Philadelphia, Pa.
A. So far as sound -with-sound is
is recorded
concerned, where signal
on track A, while signal 2 is recorded
on track B, you are correct in that
there is a distinct problem of synchronization when separate record and
playback heads are used. However, in
the case of sound -on -sound, signals
and 2 are both recorded on the same
track, and there should be no problem
in achieving synchronization with a
tape machine that has separate heads
and proper sound -on -sound facilities.
Such a machine permits you to listen
(through earphones or speakers) to
at the very instant it is being
signal
played on track A and recorded on
track B. Simultaneously, through the
mixing facility of the machine, you can
also record signal 2 on track B. The
displacement between the record and
playback heads is of no consequence.
Yes, if you wish, you can achieve
sound -on -sound synchronization by
using two tape decks and a mixer. This
would enable you to produce stereo
sound -on -sound.
Q. I have discovered,
THE AUDIO
ENGINEERING
SOCIETY'S
42nd Technical
1
Meeting and
Exhibition of
1
Professional
Equipment
1
at the
Los Angeles
Hilton
May 2-5
$
For details, write or phone:
AUDIO ENGINEERING SOCIETY
60
E.
42nd St., N.Y., N.Y.
10016
Phone:
661-8528...
AES PROGRAM INFORMATION
E.
40th St., N.Y., N.Y.
10016
Phone: 661-2355
124
or
For Tapes $
Many readers must have tapes which
they are particularly proud of. AUDIO
will pay $50.00 for the best tape of the
month-cassette or reel-to-reel. They
will be judged on technical excellence
and content. Selected tapes can be processed and marketed-if the owner
wishes. Who knows, that old tape may
make you a fortune! Please mark your
entries TAPE COMP. and send them to
AUDIO, 134 No. 13th St., Philadelphia,
Pa. 19107.
Four -Channel Conversion
Q. I have a Revox A77 tape deck
which I would like to modify so as to
be able to play four -channel stereo tapes,
such as the Vanguard Surround Stereo
series. I plan to replace the present playback head with a four -track one from
Nortronics and add two Re vox playback
amplifier circuit boards. Is this modification feasible? Will the conventional
record/playback facilities and/or qualities be affected?-Dennis J. Penner,
Pinawa, Manitoba, Can.
A. I think that this modification is
feasible, assuming that the Nortronics
head is specifically designed for mounting on your transport. You will of course
have to align the head carefully with
respect to azimuth and vertical height.
Keep the cables from the head to the
new playback amplifiers as short as
possible and of low capacitance per
foot in order to minimize treble loss.
Assuming that the Nortronics replacement head is of a quality comparable
with the original, I don't see why the
record/playback facilities in your machine should be adversely affected.
Speed Changing and Fade Outs
Q. Apart from spending $400 on a
commercial product, how is one to vary
the speed of a tape machine, with about
15% range of adjustment or even more.
the tapes I wish to copy are as
Some
much as a minor third off.
Is there a practical way of arranging
things so that, on a previously recorded
tape, a fade erase can be made after recording?-Matthew Notkins, New York,
N.Y.
A. To vary the tape speed you might
construct a power supply with variable
frequency. Such supplies have been described in the audio literature, and a
little research on your part should turn
up something suitable to your needs.
To accomplish fade erase, you might
try installing a variable resistance or
variable capacitance between the audio
oscillator and the erase head.
of
a problem or question on tape
recording, write to Mr. Herman Burstein at
Street,
North Thirteenth
AUDIO,
134
Philadelphia,
Pa.
19107. All letters are
answered. Please enclose a stamped, selfaddressed envelope.
If you have
AUDIO
6
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AmericanRadioHistory.Com
OUR 25th YEAR
APRIL 1972
Nobody ever made
a Thyadding Dolbyd
to an ordinary one.
The signal-to-noise ratio without Dolby is 45 de.
With Dolby, the signal-to-noise ratio is 55 dB.
doesn't need much help to begin with.
Which means noise is suppressed virtually to the point
Take the Harman-Kardon CAD5.
of non-existence.
Like all Dolbyized cassette decks, ours eliminates
Finally, the outside of the CAD5 is just as
tape hiss.
sophisticated as the inside. It comes with two VU meters,
But that's only one of the reasons you should buy it. an overload indicator, automatic shut-off and two sliding
The CADS was designed to give you recordings
record-level potentiometers.
that are as good as the original program material.
In all, the only thing the CAD5 doesn't have in
Wow and flutter is an extremely low 0.15%. And
common with higher -priced decks is their higher prices.
frequency response is an extremely wide 30 to 12,500 Hz
As Popular Electronics pointed out, the CADS is
with standard tape. (30 to 15,000 Hz with chromium
"a lot of recorder for *229.95." Which isn't quite correct.
dioxide tape.) So you not only hear more music, but more
The CADS now costs only $199.95.
overtones, and, therefore, more of the music.
That's perhaps the one CADS feature that isn't
Of course, there are times when you can't use
very advanced.
Dolby. (When you play non-Dolbyized, pre-recorded
For more information, write us: Harman-Kardon,
tapes, for example.) But even with the noise suppressor
55 Ames Court, Plainview, N.Y. 11803.
switched off, the CAD5 has very little noise to suppress.
One way to improve a cassette deck is by adding
Dolby. A better way is to make a cassette deck that
harman kardon
Check No.
7
on Reader Service Card
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What's New in Audio
DIN AC
Burwen wideband gain controller
Lili
The GC 101 is a two -quadrant trans multiplier,
divider,
conductance
squarer, square rooter, and gain controller. It is said to control gain over
a 60 dB range with 1.0% or 0.1 dB accuracy, with extremely low distortion,
low noise, and wide frequency response. Price: $250.00.
Check No. 80 on Reader Service Card
Mura QP-300 headphones
This four -channel headset incorporates
eight speakers-two woofers and two
QD-1
$19.95 kit
$29.95
assembled
tweeters for each ear! The size is small,
no larger than a top -line stereo headphone. Featured are a simulated leather adjustable headband and oversize
foam -filled ear cushions for comfort.
The jacks are labeled for easy identification. A felt -lined, zippered carrying
case is supplied. Price: $49.95.
Check No. 81 on Reader Service Card
No new amp
necessary
-
The easiest step to 4just
Dimensional sound
$19.95. Connect this Quadaptor to your present stereo
amplifier; add two 8 ohm
speakers like the new low cost
Dynaco A -10s, and discover
the hidden ambience (the
feeling of the concert hall) on
many of your present discs,
tapes and FM broadcasts.
New 4-D recordings can add
front and back, as well as left
and right directionality, too.
Never before has such a significant improvement in realism cost so little.
Nortronics tape accessories
This comprehensive line of professional quality tape recording accessories includes liquid head cleaner,
and life extender for cassette and 8 track cartridge, wand head demagnetizer, bulk demagnetizer, cassette
demagnetizer, splicer for '/4 -in. tapes
and cassettes, alignment tapes for
cassettes and reel to reel, and other
products.
Check No. 82 on Reader Service Card
Heath AJ-1510 digital
0luI1IaC0 I NC_
3060 Jefferson Street
Philadelphia, Pa. 19121
Check No. 83 on Reader Service Card
tuner
This FM stereo tuner kit features
keyboard tuning, with the user pressing 3 or 4 buttons corresponding to
the station frequency desired. Two
other tuning methods are also incorporated, sweep/scan and card memory. The sweep/scan mode will tune
in all stations, stereo only stations,
or stereo stations with minimum signal quality selected through adjustable
noise and automatic gain controls.
Card memory tuning has inputs for
three cards, one of which is chosen
by pressing a button. The cards need
not be removed to use other tuning
modes, and new cards can be made
from blanks supplied. Computer -type
circuitry includes phase -lock loop
Hear 4-D sound now! See
your Dynaco dealer or send
$2.95 for your Pop and Classical Dynaco-Vanguard LP.
New Literature
Heathkit offers its 1972 catalog, which
contains more than 350 do-it-yourself
electronic projects. Included are color
TV with built-in service equipment,
electronic organs, ham radio gear.
Highlight of the catalog is Heath's
AR -1500 AM/FM receiver, which was
reviewed by AUDIO in January, 1972.
multiplex demodulator, varactor frontend, and pulse -counting, averaging
frequency discriminator. The front
panel meter is switchable between signal strength and multipath indication.
Using the built-in meter and signal
lights, the builder aligns the tuner
in three no -instrument adjustments,
peaking the sweep, sensitivity, and
separation. Price: $539.95, optional
pecan wood cabinet, $24.95.
Check No. 84 on Reader Service Card
AUDIO
8
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OUR 25th YEAR
APRIL 1972
All cartridges are different.
Empire cartridges are
more different than others!
Take a technical look
for yourself.
IIV.ilìabll
generating
element
diamond
How it works.
If you know how moving
magnetic cartridges are made, you
can see right away how different
an Empire variable reluctance
cartridge is. With others, a magnet
is attached directly to the stylus,
so that all the extra weight rests on
your record. With Empire's
construction (unique of its type),
the stylus floats free of its three
magnets. So naturally, it imposes
much less weight on the record
surface.
Less record wear.
Empire's light -weight tracking
ability means less wear on the
stylus, and less wear on your
records. Laboratory measurements
show that an Empire cartridge
can give as much as 50 times the
number of plays you'd get from an
ordinary cartridge without any
measurable record wear! HI -Fl
SOUND MAGAZINE summed it up
very well by calling the Empire
cartridge "a real hi-fi masterpiece
...A remarkable cartridge unlikely
to wear out discs any more rapidly
than a feather held lightly against
the spinning groove."
Superb performance.
1000ZE/X and 999VE/X.) AUDIO
MAGAZINE said of the Empire
cartridge "outstanding square
waves ...tops in separation." HIGH
FIDELITY noted "... the sound is
superb. The performance data
is among the very best." While
STEREO REVIEW, who tested 13
different cartridges, rated the
Empire tops of all in light -weight
tracking.
X
Designates newest improved version.
World Famous Long Playing Cartridges
The light -weight Empire
cartridge picks up the sound from
the record groove with amazing
accuracy. Distortion is minimal.
(None at all could be measured at
normal sound levels with Empire's
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For further details write:
Empire Scientific Corp.,
Mtd. USA
Garden City, N.Y. 11530.
Behind The Scenes
Bert Whyte
i
I AM SURE you have noted,
in this issue of AUDIO, the emphasis is on open reel magnetic
recording. Thus it is an appropriate
time to ask how fares this granddaddy
of all magnetic tape formats?
In spite of all the doomsayers and
carping critics who have been trying to
bury open reel for the past few years,
this medium is alive and well and is
in fact flourishing. Does this run contrary to what you have been told?
The key is in recognizing the disAs
tinction between the market for open
reel tape recorders and that for open
reel pre-recorded tapes. Almost without
exception, the manufacturers of open
reel tape machines have been enjoying
excellent sales and growth. This is
particularly true with tape decks in the
higher priced category-from $300.00
upwards. It would appear that the market for low end open reel decks is
virtually dead, with the better quality
cassette decks filling this void. Nonetheless, even with the low end decks out
of the picture, the dollar volume of
open reel machines has been rising.
The sales of open reel tapes has been
slowly declining over the past few
years, but not for the reasons usually
cited, such as handling problems and
high cost. I'll go into that a bit later.
There has been a tendency on the part
of some people to lump the open reel
decks and open reel tapes together as
a single market entity, thus giving rise
to the stories of the imminent demise
of this format.
As even a casual look at the open
reel tape deck market will show,
there is plenty of activity. Hardly a
month goes by without the announcement of a new model tape deck or of
related accessories. Nor is this activity
confined to the old line established open
reel manufacturers. Look who is in
this market now
Sansui, Kenwood,
Pioneer, Panasonic-all big receiver
manufacturers and all with one or
more models of open reel tape decks.
In truth, the entire open reel market is
in a state of flux (pun intended).
Everywhere you look there is revision,
refinement,
innovation,
evolution.
Revox has new models with built-in
Dolby B type noise reduction circuitry.
Teac has their own accessory Dolby B
boxes to go with their new SL tape
decks. Akai and Tandberg have updated
their crossfield head models. Easy
accessibility and adjustment of bias
for the burgeoning array of low noise
tapes is becoming commonplace.
Ferrite and ferrite/glass heads are
being used on a number of new decks.
...
And as for four -channel open reel
decks, the variety of models is quite
astonishing. Sony has come up with
a four-channel record/play model for
$299.95. Wollensak has a deck with
two -channel record/play and fourchannel playback. Crown has the same
arrangement in one of their models
and uses up to 101/2 in. reels. In spite of
the disastrous fire at the Crown factory
last Thanksgiving Day, they will soon
be back in production on their big
"built like a battleship," 10' in.
four -channel record/play decks. Kenwood has a four-channel record/play
deck with a very handy front/rear
headphone switch. If you do any live
four-channel stereo recording, you will
find that monitoring is a sticky problem
and this headphone switch is in real
help. Astrocom will soon be producing
their Model 711, a 101/2 in. four -channel
stereo record/playback deck with individual synchronous recording facilities on all channels. By the time the
Consumer Electronics Show in Chicago
rolls around, sometime in June, there
will be very few open reel tape deck
manufacturers without a four -channel
stereo deck in their line.
Those critics who look with jaundiced
eye at the discrete four -channel open
reel format are vociferous in their
objections to the continuing proliferation of four-channel decks when
there are so few prerecorded fourchannel tapes to play on these decks.
You know, these characters have always been around since the beginning
of the hi-fi era, and they never change.
When stereo arrived about 1954 (via
tape of course) they were moaning about
the dearth of tapes, that stereo was a
"rich man's game," that they were
going to "stick to monophonic," etc.,
ad nauseam. They give me a pain.
What the hell did they expect
that
a comprehensive catalog of stereo
tapes was just going to "spring into
being"?
Fortunately, a recent development will
still the voices of these fulminating
critics or at least bring them down to
sotto voce. I told you last month about
the impending release of four-channel
open reel tapes from Project Three
and Vanguard Records, and I am happy
to confirm this. I recently spent a pleasant afternoon with Enoch Light,
discussing the entire four-channel
stereo situation. Mr. Light told me he
had done very well with four -channel
stereo tapes in 1971 and was thus
encouraged to issue nine new open
reel tapes. Incidentally, the same material will be released on discrete
...
four-channel stereo cartridges and on
Sansui and EV matrix discs. Mr. Light
intimated that henceforth four-channel
open reel tapes would be issued on a
regular basis. Mr. Light's Project Three
catalog of four-channel open reel tapes
now lists 18 productions. Vanguard
will release new open reel four-channel
tapes including pop material by Joan
Baez and others and for the classical
enthusiast such items as Handel's
"Messiah" and oratorio, "Judas Maccabeaus." Then there is the Tchaikovsky
4th Symphony with Leopold Stokowski
conducting his American Symphony
Orchestra, the Cherubini "Requiem
Mass," and several other works as yet
unknown to me. To top it all, these new
Vanguard four-channel stereo tapes will
be issued with Dolby "B" type noise
reduction in front and rear channels!
This presents an opportunity for someone like Advent or Teac to come up
with an inexpensive playback only
Dolby "B" box for the rear channels.
The anticipated introduction of the
Signetics Dolby "B" IC chip should
make such a unit a reality before long.
I should also mention a discrete fourchannel open reel tape issued by Dick
Shory's Ovation Records. Actually
it is a two reel release of mostly pop
"surround" music. It is very well done,
with intelligent use of the four -channel
medium and it has been processed with
care for an overall excellent sound
quality. Presumably Mr. Shory will
be issuing new material, in view of the
Project Three/Vanguard releases. Now,
with close to 40 four -channel open reel
tapes available, the purchase of a fourchannel open reel tape deck will be
more attractive and practical.
As I mentioned earlier, most people
seem to think that the reason for declining sales of open reel tapes is the
handling/threading problem and the
higher costs of the tapes. While admitting the threading is a problem for
some people, let me say, with malice
aforethought, that if you gave these
people the tape for free, you would be
surprised how fast they would learn to
thread tape! OK, so obviously no one is
going to give tapes away, but in the
larger cities where tape is discounted
with the same fine fervor as discs,
the same piece of music on tape or
disc has almost reached price parity.
What really has ben the trouble with
open reel tape sales is sheer availability
of the tapes in the record stores and
department stores throughout the country. As I pointed out last month, Ampex
decided to try and remedy this with a
mail order service and the response was
AUDIO
10
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OUR 25th YEAR
APRIL 1972
From Rock to Bach in 0.25 Seconds
Sony can't stop those little family arguments. But we can make
them more worth winning. And a flip of Sony's unique, knob and -lever dual selector switch gets the winner into the music of
his choice just a little quicker than an ordinary, single -knob
selector. Because until your fingertips unleash the STR-6065
receiver's performance, it might as well not be there.
So we didn't just engineer our circuits and our switches. We
human -engineered them. For instance, in normal FM -stereo
operation, all the 6065's levers make a neat row, and all its knob
indexes point straight up; ahy control that's out of place shows
up immediately.
You, who have no doubt adjusted to the crotchets of your
current equipment (and perhaps even love them). may not think
this much. Julian Hirsch, who must re-adjust to every new component that he tests, commended it: "Most receivers and amplifiers are surprisingly deficient in ease of use. Sony is to be
congratulated."
With performance this accessible, the 6065 had better
perform. And it does: 2.2 uV IHF sensitivity ("1.9 uV says
Julian Hirsh) gets you the weak FM signals; an FET front
end prevents overload from strong ones. And our high selecCheck Pe.
tivity makes tuning easier. If you find those stations easier to
listen to. you might also credit our direct -coupled amplifier
circuitry. It's supplied with both positive and negative voltages (not just positive and ground), so we don't have to put a
coupling capacitor between the speakers and the amplifier.
And, so that we can maintain full power (255 watts IHF, 160
watts RMS into 4 ohms; 220 watts IHF, 140 watts RMS at
8 ohms) or all the way down to 20 Hz at 50 watts RMS per
channel.
Which brings up another way we made the 6065's performance more accessible to you: the price. And if its moderate
price isn't accessible enough, we also make a lower -priced
model, the 6055. Its power is a little less (145 watts rather than
255 watts) as is its rated sensitivity (2.6 uV instead of 2.2). But
its otherwise almost identical.
So perhaps we can solve those family squabbles after all: a
6065 for yourself, and a 6055 for your son.
Sony Corp. of America, 47-47 Van Dam St., Long Island City, N.Y.
SONY®6065/ 6055
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so astonishing that the project was im-
LIRPA
Professor I. Lirpa, of Bucharest,
inventor of the Transpet, has sent us
details of his quadraphonic matrix. The
article may have suffered somewhat in
translation as our Romanian is nothing
to boast about-but here it is.
"Four -channel sound is not cheap as
more amplifiers are required and then
there is the decoder itself which uses
expensive ICs. Also, these ICs can cause
some phase -distortion. My idea (patents
pending, RPO) uses just two loudspeakers mounted back to back (see
Fig. 1) in the enclosure with a divider
between. This divider, with two sections
mounted at right -angles in front of
the speaker cones, forms an acoustical
matrix. It is made from wickerwork and
the twig spacings are most critical.
Two small results in poor location and
too large causes reduced separation.
The formula is:
S = A + N
A
Where
-
V
10
the spacing in cm.
A is the cone area in cm',
N is the capacity of the box in liters.
and
V is the velocity of sound in meters/
S is
sec.
Density of the material should be between 0.5 and 0.6 and the Cthula
(Young's?) modulus not less than 1.3.
The resulting algebraic coefficients at
25 degrees C. are:
Lr=a+0.31b+c-0.54d
Rr = 0.561a -0.131b + 1.81c -0.671d
L = 1.31a + 0.1b + 0.54c - d
R = -1.3a + 0.97b - 0.67c + 0.817d
The material for lab tests came from a
Chinese basket used for another re-
search project. The speaker system
should be placed as near to the center
of the room as possible and it could
be used as a coffee table."
Lf
Rf
LR
Fig. 1-Diagram of Lirpa quadraphonic
speaker.
mediately elevated from an experiment
to a permanent service. The other reason that open reel sales were declining
was that no one had done anything
about the tape hiss that was the only
flaw in otherwise fine recordings. I
covered this last month too, and I don't
want to beat a dead horse, but if repeating can help make it happen,
I'll babble on all day
process open
reel tapes with "B" Dolby and open
reel sales will be the success story of the
year. 'Nuff said.
...
All right, so the open reel tape deck
market is in a healthy state. And you
want to keep your open reel deck in a
healthy state too! In previous issues I
have gone over the importance of demagnetization, the inadequacies of most
consumer type degaussers, and the
special qualities of the R. B. Annis
Handimag unit. I duly mentioned the
importance of frequent cleaning of the
heads and tape path. Well friends, I
had an experience recently that calls for
another look at the cleaning process.
I was making some tape dubs for a
friend, playing back a 15 ips two -track
Dolby A type master and feeding the
output of the Dolby 361 units into a
Dolby B box and thence into the dubbing recorder. After setting the correct
Dolby B playback levels on the meters
of the B box, I was feeding the Dolby
tone into the recorder to set the record
levels on the blank tape I was going to
use to make the dub. Usually, it takes
two or three passes, with various adjustments of the recorder's input gain
controls to establish the proper record
level. But this time I was having problems. If the meter indicated I had to
come down slightly to achieve the
desired level, once the control was adjusted, the result was not as anticipated.
If I had to come up in level, the control
adjustment was off here too, in fact
more so than when I wanted to attenuate. Suspecting it might be dirt on the
heads I applied Q Tip and alcohol and
there was slight brown/black coloring
on the cotton, but certainly nothing that
would have caused the noted fluctuations. Tried to set levels once more ..
Same result. Tried again, and this time
the left channel was way down (later
measurement showed it to be off by
18 dB). I thought that it must be trouble
with the record amplifier. Since the home
service base of the manufacturer of the
recorder was just a few minutes drive
from my home, I took the recorder
there. Sure enough their tests showed
the 18 dB drop. But imagine my chagrin when the technician said that it
was just a dirty head! I protested that
not only do I clean the deck's heads
about every 3rd or 4th recording, but
that I had just cleaned the heads before
I came to him. The technician picked
up what looked like a miniature tooth
brush, except that instead of bristles,
there was a square of fairly stiff white
felt cemented to it. He moistened it
with alcohol and really scrubbed the
heads. The design of the "toothbrush"
allows you to exert considerable pressure. Needless to say, the once white
tip was almost dead black. The deck
was then swept from 20 to 20kHz on a
Bruel and Kjaer frequency spectrum
analyzer with graphic readout. The
chart was just as pretty as could be.
I was still shook up that head dirt had
really been the cause of the trouble.
Nevertheless, I armed myself with a
supply of the fancy "toothbrush"
cleaners, and it was a good thing I
did for later I ran into the same trouble.
Now, depending on the brand of
recording tape, some shed oxide more
than others. But in general the top name
brands of tape are rarely problemsome.
The tape I was using was a top brand
of premier low -noise formulation I
had used with complete satisfaction
many
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But things
do
plasticizer, and adhesive are not driven
off in the curing process, so the oxide
surface remains ever so slightly
"tacky," but enough that when the
tape passes over a head, guide or
roller, the friction created rolls off
tiny little balls or "pearls" of oxide and
adhesive. Naturally tape passing over
this obstruction is lifted from the head
with resultant drop in signal. The
tenacity of this oxide "gunk" is incredible. Obviously the usual Q Tip
measures are ineffective and the added
pressure and compactness of the felt
is needed to dislodge the gunk. Usually when you buy a carton of ten
or a dozen rolls of tape, they are all
of the same "emulsion" number. If
you have trouble with one of the tapes,
you will almost certainly have it with
the other tapes in the carton. Your only
recourse is with the manufacturer, and
in the meanwhile try another batch of
tape. Thus it was with me ... using tape
of another manufacture I did not encounter any troubles. In the light of my
experience, I'm going to clean my heads
more thoroughly in the future and keep
an eye peeled for any tapes which seem
to shed more oxide than usual. As a
final note . .. I'm trying to find out
the name of the manufacturer of the
fancy "toothbrush" cleaner so they can
be bought separately and in bulk.
At present they come as part of a cleaning kit.
AUDIO
12
times before.
happen ... I found out that this particular batch of tape was exhibiting a
phenomenon known as "pearling."
Evidently under certain circumstances,
some of the volatile agents in the binder,
OUR 25th YEAR
APRIL 1972
After the monthly
breakthroughs and
revolutions in speaker
design, how come
the Rectilinear III
still sounds better?
Figure it out for yourself.
More than five years ago,
without much fanfare, we came
out with a very carefully engi-
neered but basically quite
straightforward floor -standing
speaker system. It consisted of
six cone speakers and a crossover network in a tuned enclosure; its dimensions were 35" by
18" by 12" deep; its oiled walnut cabinet was handsome but
quite simple.
That was the original Rectilinear Ill, which we are still selling, to this day, for $279.
Within a year, virtually every
hi-fi editor and equipment re-
viewer went on record to the
effect that the Rectilinear Ill was
unsurpassed by any other
speaker system, regardless of
type, size or price. (Reprints still
available.)
Then came about forty-seven
different breakthroughs and
revolutions in the course of the
years, while we kept the Recti-
linear Ill unchanged. We
thought it sounded a lot more
natural than the breakthrough
stuff, but of course we were prejudiced.
Finally, last year, we started to
make a lowboy version of the
Rectilinear Ill. It was purely a
cosmetic change, since the two
versions are electrically and
acoustically identical. But the
lowboy is wider, lower
and more sumptuous, with a very
impressive fretwork grille. It
measures 28" by 22" by 121/4"
deep (same internal volume) and
is priced $20 higher at $299.
The new version gave Stereo
Review the opportunity to test
the Rectilinear Ill again after a
lapse of almost five years. And,
lo and behold, the test report
said that "the system did an essentially perfect job of duplicating our "I ive music" and that both
the original and the lowboy
version "are among the best sounding and most 'natural'
speakers we have heard." (Reprints on request.)
So, what we would like you to
figure out is this:
What was the real breakthrough and who made it?
For more information, including detailed literature see your
audio dealer or write to Rectilinear Research Corp., 107
Bruckner Blvd., Bronx, N. Y.
10454.
new
Rectilinear III
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AmericanRadioHistory.Com
We believe the
Heathkit AR -1500
to be the world's finest
stereo receiver.
The experts
seem to agree.
"The AR -1500 is the most powerful and sensitive receiver we have ever measured ..."
- JULIAN HIRSCH, Stereo Review.
"... a stereo receiver easily worth twice the cost (or perhaps even more) ..."
- Audio Magazine.
"Great new solid-state stereo receiver kit matches the demands of the most golden of golden ears ..."
- Radio Electronics.
The Heathkit AR -1500 AM/FM/FM-Stereo Receiver
www.americanradiohistory.com
AmericanRadioHistory.Com
...
379.95* (kit, less cabinet)
Mr. Hirsch goes on to say: "The FM tuner section of the AR 1500 was outstandingly sensitive. We measured the IHF sensitivity at 1.4 microvolts, and the limiting curve was the steepest
we have ever measured ... The FM frequency response was
literally perfectly flat from 30 to 15,000 Hz ... Image rejection was over 100 dB (our measurement limit)...
"The AM tuner was a pleasant surprise ... It sounded very
much like the FM tuner, with distinct sibilants and a quiet
background, and was easily the best -sounding AM tuner we
have had the pleasure of using...
"... all input levels can be matched and set for the most effective use of the loudness compensation. This valuable feature
is rarely found on high-fidelity receivers and amplifiers...
"The phono equalization was perfectly accurate (within our
measuring tolerances) .. The magnetic phono-input sensitivity was adjustable from 0.62 millivolt to about 4.5 millivolts,
with a noise level of 66 dB, which is very low ... When
properly set up, it would be impossible to overload the phono
inputs of the AR-1500 with any magnetic cartridge...
.. it significantly bettered Heath's conservative specifications. Into 8 -ohm loads, with both channels driven, the continuous power at clipping level was 81.5 watts per channel.
Into 4 ohms it was 133 watts per channel, and even with 16ohm loads the receiver delivered 46.5 watts per channel.
Needless to say, the AR -1500 can drive any speaker we know
of, and with power to spare...
"At 1,000 Hz, harmonic distortion was well under 0.05 per
cent from 1 to 75 watts per channel ... The IM distortion was
under 0.05 per cent at levels of a couple of watts or less, and
gradually increased from 0.09 per cent at 10 watts to 0.16 per
cent at 75 watts ... The heavy power transformer is evidence
that there was no skimping in the power supply of the AR 1500, and its performance at the low-frequency extremes
clearly sets it apart from most receiver's...
"Virtually all the circuit boards plug into sockets, which are
hinged so that boards can be swung out for testing or servicing without shutting off the receiver. An `extender' cable
permits any part of the receiver to be operated in the clear
even the entire power -transistor and heat -sink assembly! The
245 -page manual has extensive tests charts that show all voltage and resistance measurements in key circuits as they should
appear on the receivers built-in test meter...
"With their well-known thoroughness, Heath has left little to
the builder's imagination, and has assumed no electronic
training or knowledge on his part. The separate packaging of
all parts for each circuit board subassembly is a major boon...
"In sound quality and ease of operation, and in overall suitability for its intended use, one could not expect more from
any high-fidelity component."
-
-
From the pages of Audio Magazine:
..the AR -1500 outperforms the near-perfect AR -15 in almost every important specification...
"The FM front end features six tuned circuits and utilizes
three FETs, while the AM RF section has two dual -gate
MOSFETs (for RF and mixer stages) and an FET oscillator
stage. The AM IF section features a 12 -pole LC filter and a
broad band detector. The FM IF section is worthy of special
comment. Three IC stages are used and there are two 5 -pole
LC filters...
"... IHF FM sensitivity ... turned out to be 1.5 uV as opposed
to the 1.8 uV claimed. Furthermore, it was identical at 90
MHz and 106 MHz (the IHF spec requires a statement only
for IHF sensitivity at 98 MHz but we always measure this
important spec at three points on the dial). Notice that at just
over 2 microvolts of input signal S/N has already reached 50
dB. Ultimate S/N measured was 66 dB and consisted of small
hum components rather than any residual noise. THD in
Mono measured 0.25%, exactly twice as good as claimed!
Stereo THD was identical, at 0.25%, which is quite a feat...
.. the separation of the multiplex section of the AR -1500
reaches about 45 dB at mid-band and is still 32 dB at 50 Hz
and 25 dB at 10 kHz (Can your phono cartridge do as well?)
"The real surprise came when we spent some time listening
to AM ... This new AM design is superb. We still have one
classical music station that has some simultaneous broadcasting on its AM and FM outlets and that gave us a good opportunity to A-B between the AM and FM performance of the
AR -1500. There was some high -frequency roll -off to be sure,
but BOTH signals were virtually noise -free and we were hard
pressed to detect more THD from the AM than from the FM
equivalent. Given AM circuits like this (and a bit of care on
the part of broadcasters), AM may not be as dead as FM
advocates would have us believe! ...
"Rated distortion [0.25%] is reached at a [continuous] power
output of 77.5 watts per channel with 8 ohm loads (both
channels driven) . At rated output (60 watts per channel)
THD was a mere 0.1 % and at lower power levels there was
never a tendency for the THD to `creep up' again, which indicates the virtually complete absence of any `crossover distortion' components. No so-called `transistor sound' from
this receiver, you can be sure. We tried to measure IM distortion but kept getting readings of 0.05% no matter what we
did. Since that happens to be the `limit' of our test equipment
and since the rated IM stated by Heath is 'less than 0.1% at
all power levels up to rated power output' there isn't much
more we can say except that, again, the unit is better than the
specification we just don't know how much better...
"As for the amplifiers and preamplifier sections, we just
couldn't hear them and that's a commendation. All we
heard was program material (plus some speaker coloration,
regrettably) unencumbered by audible distortion, noise, hum
or any other of the multitude of afflictions which beset some
high fidelity stereo installations. The controls are easy to use
and quickly become familiar...
"As always, construction instructions are lucid enough for the
inexperienced kit-builder and there is enough technical and
theoretical information to satisfy even the most knowledgeable audio/ RF engineer."
-
-
And Radio Electronics had this to say:
"As you know, the original, the AR -15, has been widely acclaimed as one of the very best stereo receivers that has ever
been made. Therefore, it's hard to imagine that anyone has
gone ahead and built a better one. But spec for spec, the AR 1500 is ahead of the AR -15..."
Kit AR-1500, less cabinet, 53 lbs.
379.95*
ARA -1500-1, walnut cabinet, 8 lbs.
24.95
See and hear the new AR -1500 at your nearest Heathkit Electronic Center ... order direct from the coupon below ... or
send for your free Heathkit catalog.
HEATHKIT
FIEATHKIT ELECTRONICS CENTERS
ARIZ.: Phoenix, 2727 W. Indian School Rd.; CALIF.: Anaheim, 330 E.
Ball Rd.; El Cerrito, 6000 Potrero Ave.; Los Angeles, 2309 S. Flower
St.; Redwood City, 2001 Middlefield Rd.; San Diego (La Mesa), 8363
Center Dr.; Woodland Hills, 22504 Ventura Blvd.; COLO.: Denver,
5940 W. 38th Ave.; FLA.: Miami (Hialeah), 4705 W. 16th Ave.; GA.:
Atlanta, 5285 Roswell Rd.; ILL.: Chicago, 3462-66 W. Devon Ave.;
Downers Grove, 224 Ogden Ave.; KANSAS: Kansas City (Mission),
5960 Lamar Ave.; MD.: Rockville, 5542 Nicholson Lane; MASS.: Boston (Wellesley), 165 Worcester St.; MICH.: Detroit, 18645 W. Eight
Mile Rd. & 18149 E. Eight Mile Rd.; MINN.: Minneapolis (Hopkins),
101 Shady Oak Rd.; MO.: St. Louis, 9296 Gravois Ave.; N.J.: Fair
Lawn, 35-07 Broadway (Rte. 4); N.Y.: Buffalo (Amherst), 3476 Sheridan Dr.; New York, 35 W. 45th St.; Jericho, L.I., 15 Jericho Turnpike;
Rochester, Long Ridge Plaza; OHIO: Cincinnati (Woodlawn), 10133
Springfield Pike; Cleveland, 5444 Pearl Rd.; PA.: Philadelphia, 6318
Roosevelt Blvd.; Pittsburgh, 3482 Wm. Penn Hwy.; TEXAS: Dallas,
2715 Ross Ave.; Houston, 3705 Westheimer; WASH.: Seattle, 2221
Third Ave.; WIS.: Milwaukee, 5215 Fond du Lac.
Dept. 41-4
Benton Harbor, Michigan 49022
HEATH COMPANY,
Enclosed is $
by return mail.
Enclosed is $
Schlumberger
plus shipping. Please send my AR -1500
plus shipping for ARA -1500-1 walnut
cabinet for
AR -1500.
Please rush my free Heathkit Catalog.
FREE CATALOG...de- Name
scribes AR -1500, plus over
350 other fun -to -build Address
home and hobby kits. Mail
State
lip
coupon or write Heath City
Company, Benton Harbor,
Prices & specifications subject to change without notice.
Mich. 49022.
*Mail Order Prices; F.O.B. Factory
HF -255
L.
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Choosing A Tape Recorder
H. W. Hellyer
0
did not have
this problem. Choosing a tape
recorder at the turn of the
century was a simple matter-it was
Magnetophon or nothing.
Now we have hundreds from which
to make our choice, all-if you believe
the advertisements-offering something
special. The problem is, very often, to
distinguish between those that offer
what you want and those which are
simply embellishing what may be a
basically good model, but for which
you pay more, get more, but use less.
First-read the reviewers. Read 'em
diligently. Contrary to many opinions,
these gents (myself among them, though
not in these pages or even in this
country) do their best to describe good
and bad points of the equipment sent
to them, adding a personal nuance here
and there, which their own coterie of
followers will learn to love or hate,
and should always back their opinions
with the hard bedrock of measured fact.
UR GRANDFATHERS
Second-if there is a point on which
you are not clear, then ask! Ask the
reviewer, ask the Editor, ask Joe Giovanelli; or for specific advice on tape
questions ask Herman Burstein, ask
the Editor, or, if you are prepared
to wait for the Transatlantic carrier
pigeons, ask Donald Aldous or me-but
ask.... We are here to serve. We do
not want you to waste your money,
tuck the tape recorder under the bed
and go back, disgruntled, to off -the -air
programs of someone else's choosing.
If there is a question about a switch
function, a system matching, interpretation of technical terms, or any other
suchlike bother, then we should be able
to help you. But if it is a question of
whether A is better than B, you may
not be so easily served.
With tape, it depends on what you
mean by "better."
Less noise? Well, yes, the noise ,reduction systems do have an effect and
it is greatest with necessarily slow -speed
cassettes.
For reel-to-reel machines it may
16
seem less important. But tape hiss, the
everpresent bugbear, is also relevant at
higher speeds and on wider tracks. So
the "add-on" noise reduction device is
worth consideration.
Some tape recorders will already
have the noise reduction facility builtin. Watch for those which add distortion or rob your recording of its
dynamic range. There are several
methods: One aim of most is to reduce
the higher frequencies when the overall
signal is lowest. Using the same argument as the more sophisticated Dolby,
they sense signal level and apply a
frequency -conscious stop filter. Some
of these can be viciously potent; my
advice is record and replay a familiar
piece of music, then listen very carefully for those artificial rises and falls
in ambient noisé level that give the
game away.
Some machines do it both ways,
that is, they apply extra pre -emphasis
during recording or can be switched to
high-energy tape activation, then
utilize a noise reduction switch on replay. Although these refinements are
more often encountered on cassette
machines, where practically any improvement has to be beneficial (Ouch!
Ed.), makers of reel-to-reel tape
recorders are adding all sorts of similar
sophistications.
Choice of a reel-to-reel tape recorder,
as distinct from a cassette or cartridge
machine, argues that one wants the
choice of speeds or some greater trackswitching flexibility than is currently
available because of cassette head size
and mounting restrictions.
Accepting that argument, you should
look for the tape recorder that does
what you particularly want and no
more, but one that does it as well as
can be.
Tape recorder makers will not love
me for saying so, but there's a heck of
a lot of apparatus gathering dust because its promise outlived its performance. New models come along:
they glitter more, have a lot of inviting
facilities, merit a very close look. ..
But when you look, remember that a
"track -transfer, multi -sound, echo -flip
device" may sound impressive when
you show your friends, but may have
cost you the dollars you could have
spent in getting the simpler, higher speed, better -performing machine.
Make your choice logically. Say:
(1) What do I want to do with this
thing? (2) What am I likely to want to
do later? and (3) How about after that?
Point
is the most important as
well as the most immediate. If your
main work is vocal-interviews, reports of meetings, out -and -about effects
-you need as good a microphone as
you can get. Likely you will have
bought it or still be drooling over the
catalogs. OK, don't waste money on
the machine with mic. Not unless that
machine, for other reasons, seems the
best.
General purpose work is a vague
term, but we all know what it means.
Monday you just had to catch Station
Zee -Dee -Kay giving forth on Mahler's
love -life; Tuesday was when Junior
visited, with his newest -born just
gurgling to be historied; Wednesdaywell, wasn't that the day the Stag Club
just "took off" and haven't you just got
to prove that Joe had said what he did
before carting your precious tapes and
slides to the PTA social on Thursday
for your annual lecture on the Lakes
of Saskatchewan? General purpose
means what it says: your machine has
to withstand a bit of hard handling
and maybe a can of beer in its innards.
.
1
So choose it, expecting the worst.
But remember, that Mahler has to
come over soft and clear, and you'll
do that better at a higher speed, if
quality of performance matters more to
you than a miserly saving on the cost of
tape.
Which brings up another point. Tape
length, and, related to it, tape thickness.
Calculate your probable program length
AUDIO
OUR 25th YEAR
APRIL 1972
We doubt that anyone will be overly surprised to learn that our newest loudspeaker sounds
terrific. Most people really expect KLH to make
terrific sounding things. But at $ó2.50t a piece,
our new Model Thirty -Eight delivers an amount and
quality of sound that we think will astonish even
our most avid fans. The bass response is absolutely
staggering; the transient response is flawless; and
the Thirty -Eight's overall smoothness matches anything we've ever heard. Most important, you can
use a pair of Thirty -Eights with virtually any mod-
estly priced receiver. What good is an inexpensive
pair of loudspeakers that need a $400 receiver to
effectively drive them?)
The Thirty -Eights are at your KLH dealer now.
After hearing them, we think you'd pay $125 for
just one. But $125 buys you two. Which has got to
make the Thirty -Eights the biggest stereo bargain
since ears.
For more information, visit your KLH dealer or
write to KLH Research and Development, 30 Cross
St-eet, Cambridge, Mass. 02139.
The New KLH Model shirty-Eight.
Two for $125.
1111111111111111M11,10111111111111*
RESEARCH AND DEVELOPMENT
LH
A
(Suggested east coast retail
Division of the Singer Con acny
ce. Slightly higher
it
the south and west.
'A 'rademark of
Check No. 17 on Reader Service Care
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AmericanRadioHistory.Com
The Singer Company.
Bringing up
the rear.
The
ADC 404A.
If you've hesitated about
making the switch to four
channel because of the
complications posed by
rear speaker placement,
relax.
We've got the answer.
It's our ADC 404A.
The choice of leading
testing organizations for
two channel systems,
this unobtrusive, high
quality, low cost speaker
is also the perfect solution to the biggest hang
up in four channel sound
reproduction.
The ultracompact
ADC 404A
(117/8" x 734"
x 81/4") pro-
vides the clean,
uncolored,
well balanced
sound normally associ-
ated with far larger and
more costly systems.
Best of all, its small
size and light weight
enormously simplify
placement problems.
Just place a pair on a
back wall and almost
before you can say four
channel, you're hearing
it.
And once you've heard
the 404A, we think you'll
agree that with ADC
bringing up the rear,
you're way ahead.
Manufacturers suggested retail price $45.
Pickett District Road,
New Milford, Conn. 06776
and add a bit for fluffing. There are
plenty of good tape length/time/grade
tables around-no need to bore you with
another. But let me remind you that,
for example, a mil polyester tape on a
7 -in. reel (1800 feet length) can give
you 45 minutes of recording if you are
using half-track stereo at 7' ips, to
get the best signal-to-noise ratio and
dynamic range from your machine.
Use a quarter-track machine (I don't
like the term 4 -track in this context,
with so much multi -track studio stuff
about) and you'll double the playing
time, but have to invert reels midway
through that doubled performance.
The use of 33/4 ips would have gotten
you the same playing time, but for that
you would have sacrificed a couple of
thousand Hz frequency response at the
top end (and don't kid yourself, the
hiss is not all up there!) and had to
put up with a fractionally worse wow
and flutter performance.
The point I am trying to make is that
the real perfectionist will go for the
highest speed and the widest track and
to hell with playing time per spool.
Bert Whyte was enthusing about the
Nagra-only just breaking out into
stereo, forsooth!, when we are all in a
quadraphonic fever-and my personal
memories of this machine are a blissful month of full -track 15 ips recording
while its owner, an explorer friend of
mine, laid low by some bug, left it in
my loving care. As Bert says, if only
we could run two units in sync, we
could make such things as outdoor
four -channel stereo recordings.
Coming down out of the clouds a
while, let me say that, as an engineer,
I have the utmost difficulty in choosing
tape recorders. I am always more concerned with the design factors and the
probable life, the true specification
(not just what is quoted, which can be
regrettably ambiguous), and the basic
facilities of the machine.
This is all the more important when
reel-to-reel recorders are considered.
Mainly because the range of facilities
becomes so much wider-and the ultimate quality realizable so much higher.
(That should offend a few marketeers!
Ed.)
I assume you are reading this because
the virtues of easy loading, portability,
and a library you can carry in your
auto map pocket are not so important
as those of wider frequency range,
better speed stability, improved signalto-noise ratio (Dolby notwithstanding),
and a tremendous eruption of facilities.
Choosing your reel-to-reel recorder
is truly a matter of matching your needs
1
to your pocket. In a challenged market,
you can be sure that the goods are
competitive. If you are a true tape
enthusiast, now is the time to invest.
Quadraphonics, as far as you are concerned, is an impossible or impossibly
costly conversion from two -channel
stereo. If you want surround sound, get
in there now. Makers are jostling for
your custom and the technology is not
likely to be outdated in the lifetime of
your machine-all the headwork is
going into broadcasting and discs.
The design commitment in tape
recording today is toward getting more
flux on the tape, tailoring circuitry to
get less noise without losing or distorting signal, and-most significantly-
motor control.
Where only one of the "big boys"
had a servo -controlled motor a year
ago, several are seeing the advantage of
this device in 1972 and there are more
waiting in the wings. It calls for a hunk
of circuit, but that is no great problem
in these days of ICs. It gives spot-on
speed and makes for less hum radiation,
besides cutting down weight.
Automatic recording level control,
once the specialty of the portable, is
creeping into more and more of the
larger models. So is single meter (peak selective) indication. Both can have
advantages in the right situation. Question is, is it yours?
How to choose from the welter of
superlatives in the catalogs? The
answer, as I said at the outset, is: Read
your reviewers. Find whose opinion
most matches your own experience or
who consistently convinces you. Before making a choice, read as many
independent reports on the model as
you can. Shop around and try out that
all-important factor, operability.
Yes, I know the word's not in Webster's. I coined it a coupla years ago
when reviewing a portable which was
the first I'd met where all the controls
seemed to "come to hand." And that
was a reel-to-reel machine, incidentally.
Make your choice the same way:
Check the specs., read the reports, and
handle it. If you are buying across the
counter, be sure you get the chance to
try before you buy. If you are buying
mail order, well, you take a chance
along with your discount.
Note that I've named no names?
Deliberately. You have to do the choosing, friend: all I can hope is that my
remarks may have sparked off a few
ideas to help you. Only one thing is
certain-the one you finally select will
be the one you just can't quite af-
ford....
AUDIO
18
Check No. 18 on Reader Service Card
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AmericanRadioHistory.Com
OUR 25th YEAR
/E
APRIL 1972
if you go for f
channel...
you don't have to go for broke
Buy yourself a miracle for as little as $214.95 That's all
it takes to get your conventional two-channel stereo to do
anything any total four -channel receiver and control center
can do, now or in the future.
The Sansui QS500 and QS100 converters are complete
Four -Channel Synthesizer -Decoder -Rear -Amplifier -and Control -Center combinations that transform standard two channel stereo totally. The only other equipment you need
is another pair of speakers.
You can decode any compatibly matrixed four -channel
broadcasts or recordings and reproduce them in four authentic channels. You can detect the ambient signals
present in most two -channel recordings or broadcasts and
propagate them through the rear channels. In-Sansui matrixing, the exclusive phase -shift technique prevents the cancellation of some signals and the change in location of
others that occur in many matrixing systems. And the
exclusive phase modulators restore the effect of the live
sound field.
You can plug in a four -channel reel-to-reel or cartridge
deck or any other discrete source. In the future if you
should have to you can add any adaptor, decoder or what have -you for any four-channel system for disc or broadcast
that anyone's even hinted at. And a full complement of
streamlined controls lets you select any function or make
any adjustment quickly and positively.
The QS500 features three balance controls for front -rear
and left-right, separate positions for decoding and synthesizing, two -channel and four -channel tape monitors, electrical
rotation of speaker output, alternate -pair speaker selection,
and four VU meters. Total IHF power for the rear speakers
is 120 watts (continuous power per channel is 40 watts at
4 ohms, 33 watts at 8 ohms), with TH or IM distortion below
0.5% over a power bandwidth of 20 to 40,000 Hz. In its own
walnut cabinet, the QS500 sells for $289.95
An alternate four -channel miracle -maker is the modest
but well -endowed QS100, with total IHF music power of 50
watts (continuous power per channel of 18 watts at 4 ohms
and 15 watts at 8 ohms). In a walnut cabinet, it sells for
$214.95
-
-
..
,P e, SANSUI ELECTRONICS CORP.
,
conran.,.. v.sw
Woodside, New York 11377
Gardena, California 90274
ELECTRONIC DISTRIBUTORS (Canada), Vancouver 9, B.C.
SANSUI ELECTRIC CO., LTD., Tokyo, Japan Sansui Audio Europe S. A., Antwerp, Belgium
Check No. 19 on ReaderService Card
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AmericanRadioHistory.Com
Refacing
Tape Recorder
Heads
William B. Fraser
LONG AGO, a customer
brought me a tape recorder for
repair. The complaint was
poor and erratic sound.
The recorder was an expensive one
and almost new. It didn't seem likely
that the electronics were at fault. A
check of the heads located the problem
immediately. The playback head had
been mounted incorrectly, so that the
height was grossly out of adjustment. In
the meantime, the machine had been
operated enough so that an obvious
tape groove was visible on the face of
the head. Under these circumstances,
it is usual to consider the head has
been ruined. The conventional solution
is to install a new head.
But a new head was expensive and
not readily available. Further, the
customer was anxious for speedy repairs. After some thought, I decided
to attempt to salvage the head by refacing it. I have not heard of this being
done in a service shop (or elsewhere
for that matter) and approached the
job with some apprehension. Fortunately, one thing was going for me. The
head was ruined anyway, so what was
there to lose?
The results of this first attempt were
so satisfactory that subsequently I have
refaced about a dozen other heads with
100% success. I have often wondered
how long these reconditioned heads
would last. So far it has been impossible
to determine, simply because no customer has ever returned with a complaint. As a guess, perhaps the initial
life expectancy of the head has been
doubled.
Anything on the face of a tape recorder\ head which interferes with intimate contact between head and tape
will cause unsatisfactory operation. A
deep tape groove or a scratch or an
erratic or incorrectly located wear
pattern all cause the tape to lose contact
with the head. It is these types of abnormalities which are considered in this
article.
It takes me about one hour of grinding and polishing to reface even the
NOT
worst head. Add to that the time to
remove the head, then reinstall and
align, and the entire job runs two to
two and a half hours. This is a considerable saving to the customer over
the cost of a new head. Occasionally,
you will run into a head that is so
severely worn that refacing should not
be attempted. This is the time when you
must depend upon your good judgment.
In performance, a refaced head compares favorably with a new head in
all important characteristics.
Here's how the job is done. First get
the necessary materials. They are all
inexpensive and readily available:
1. A wooden board on which to do
the grinding and polishing. A small
kitchen cutting board about 8 X 10 in.
does nicely. It must have a smooth, flat
surface.
2. One sheet wet sanding paper, 220
grit.
3. One sheet wet sanding paper, 400
grit.
4. One
sheet wet sanding paper, 600
grit.
5. Jar of silver polishing cream,
Wright's or equivalent.
6. Piece of soft flannel cloth about
a foot square.
7. Magnifying glass, about 10 x.
Having assembled the equipment,
you are ready to start. Remove the
head from the machine and disassemble
any mounts or shields which interfere
with access to the face. Examine the
wear pattern to make sure the head can
be salvaged and to determine what you
have to do. Let us assume the wear
consists of a grove about three or four
times the thickness of a 1 mil tape. This
amount of wear will require a good
deal of grinding, and so we start with
the coarse (220) paper. The grinding
should be done wet, that is with a small
flow of water on the grit paper. Wet
grinding produces a smoother result
than dry grinding. A pressure of no
more than six to eight ounces should
be used, as heavier pressure will make
deep gouges in the face of the head. If
you're not sure what a 6 ounce pressure
20
out a pressure gauge and find
out. It's important. Hold the head by
its sides with the face against the grit
paper. As you look downward toward
the work, use a rotary motion of the
hand, making circles about three or
four inches in diameter. Simultaneously
with this rotary motion, rock the head
back and forth so the entire face is
exposed to the grinding action. At all
times keep an even pressure on the
head. Occasionally, turn the head end
for end to insure even grinding.
Examine the work frequently under the
microscope. When the depth of the
groove has been reduced to about half
the thickness of a one mil tape, it is
time to use the medium (400) paper.
Keep up the grinding until the groove
is almost eliminated, then finish grinding with the fine (600) paper. Avoid
grinding more than necessary, but be
certain all traces of the groove have
been eliminated.
The next step is to polish the face.
Put aside all abrasive papers and wash
the cutting board. Fold the flannel
cloth double, moisten it, apply a small
amount of polishing cream, and polish,
using the same techniques as employed
during grinding. Fifteen minutes of
polishing usually will produce an excellent surface finish-provided your grinding was correctly done.
Let us retrace our steps for a moment
to the point when we made the initial
examination of the head to determine
the depth and extent of the wear pattern. If the wear is light, the grinding
should start with the medium or fine
grit rather than the coarse grit. In case
the coarse grit is employed late in the
grinding process, deep scratches will be
left in the face of the head. These tend
to accumulate debris and interfere with
head -to-tape contact.
Well, that completes the job as far
as refacing is concerned. Of course,
you must reassemble the equipment,
align the heads, and test the equipment. As far as the head is concerned,
you should achieve specified per/E
formance of the recorder.
is, get
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
OUR 25th YEAR
APRIL 1972
The Pick-Up Pros.
Artie Altro makes the WOR-FM sound, while Eric Small, Sebastian Stone and Promotion Director, Kim Olian look over a new album.
WOR-FM, the country's leading FM/Stereo
rock station, has been using Stanton cartridges
since its inception.
Program Director Sebastian Stone likes the
smooth, clean sound the Stanton delivers; the way
it is able to pick up everything on the record so that
the station can assure high quality transmission
of every recording.
Eric Small, Chief Engineer for WOR-FM,
likes the way that Stanton cartridges stand up under
the wear and tear of continuous use. "We standardized on Stanton a couple of years back,"
Small said, "and we haven't had a cartridge failure
since. Studio Supervisor Artie Altro concurs.
Whether you're a professional or simply a
sincere music lover, the integrity of a Stanton
cartridge delivers the quality of performance
you want.
There are two Stanton professional
cartridge series. The Stanton 681 Series is engi-
neered for stereo channel calibration in record
studios, as well as extremely critical listening. The
500 AL Series features design modifications which
make it ideally suited for the rough handling
encountered in heavy on -the -air use. In fact, among
the nation's disc jockeys it has become known
as the "industry workhorse."
All Stanton cartridges afford excellent
frequency response, channel separation, compliance
and low mass and tracking pressure. And every
Stanton cartridge is fitted with the exclusive
"longhair" brush to keep grooves clean and protect
the stylus. They belong in every quality reproduction system-broadcast or high fidelity.
For complete information
and specifications on Stanton
cartridges, write Stanton
Magnetics, Inc., Terminal Drive,
Plainview, L.I., N.Y. 11803.
sTaNTon
All Stanton cartridges are designed for use with all two and four -channel matrix derived compatible systems.
Check No. 21 on Reader Service Card
Mathematics
Beginners
Part Four of a Series by Norman Crowhurst
George wandered in Henry's office, when
neither of them were too busy,
George had been thinking quite a little
about their earlier discussions on calculations associated with electronics.
"You know," George opened the conversation, "when I took some course
in mathematics for electronics, or whatever it was called, there was one thing
that always left me in the air. It strikes
me now that perhaps you could help
me understand it."
"What's that?" questioned Henry.
"Maybe it's really more than one
thing, but they all relate to calculations
involving reactances," George responded. "I don't know, somehow I've
drifted into depending on charts of one
kind or another and, if I can't find a
handy -dandy chart that just suits my
needs, I'm lost. Of course, it is always
nice to have a chart do the work, but
I'd be a lot happier if I knew what work
the chart did for me."
"You mean you're always afraid,
when you don't know what you're
doing, that you might misuse the chart,
because you don't understand what it's
supposed to do?" asked Henry.
"That's about it."
"So ask me-perhaps we can figure
it out," said Henry.
"I think the first thing that bothered
me is that 2 -pi bit and `angular freBY THE NEXT TIME
quency' or something, in the formulas
for reactance of inductances and capacitances. Then, when you get past that,
there's the whole vector addition bit,
where you add quantities together, but
they don't follow the rules of addition."
"Let's take one piece at a time,"
suggested Henry. "The word `reactance'
means something fundamentally different from `resistance'. A resistance
`solidly' resists current flowing through
it. The voltage that `registers' that resistance is always strictly proportional
to the current that causes it. If a resistance is 100 ohms, and the current 20
milliamps, then voltage will be 20 x
100 = 2,000 millivolts, or 2 volts. That's
true at every instant, in a resistance, no
matter how voltage and current change.
"But in reactances it's different. It
is not current or voltage that directly
produces a voltage or current effect, as
in resistance, but change of current
that produces voltage, or vice versa.
Let's take inductance first. A Henrythe unit of inductance-is defined as
having a value that, when current
changes at 1 amp per second, the reactive voltage generated is 1 volt."
"Yes," responded George, "I remember that bit, now you repeat it, but
from there on, the whole thing lost me,
pretty fast. The teacher got into the
angular measure of angles ` or something
...."
"You mean the circular measure of
angles, as opposed to the more conventional `degree' measure," suggested
Henry.
"I guess that's it," George said, "And
then a 2-pi got in there, and I never
could see how frequency got into the
picture. I used the formula for quite a
while, without knowing why, and then
I found charts took all the trouble out
of it, but I've never been happy about
it."
"First let us look at the circular measure of angles," suggested Henry, as he
started to draw. "Really, it's the degree
measure that starts the difficulty. There
is no real reason, except that somebody
a long while ago did so quite arbitrarily, for dividing a circle into 360 equal
parts called `degrees' or a right angle,
which is a quarter-or 'quadrant'-of a
circle, into 90 of them.
"The circular measure of angles simply takes a radius, rotates it from its
starting point, so one end stays at the
center and the other end follows the
circumference of a circle, and the movement along the circumference, measured
with the radius as unit length, describes
the angle made."
Henry was drawing as he did this,
and George picked it up. "Oh, I see, so
when you've completed a circle, which
degree measure calls 360 degrees, the
AUDIO
22
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OUR 25th YEAR
APRIL 1972
circumference is 2 -pi times the radius
that draws it?"
"That's the idea," said Henry. "So
far, so good. Now we come to apply that
to a sine wave."
"That's another place where I got
lost," said George. "Nice neat 30, 60,
90 degree angles, with 45 in there somewhere, made easy figuring, but this `pi
radian' bit lost me."
"Do you remember the ratio that defines the sine of an angle?" asked Henry.
"Yes," replied George, "in fact that
is all I can remember of my trig studies,
I think. The sine is the `opposite over
the hypotenuse'." He drew it as he said
what's that, a little more than 360
ohms?-at line frequency."
Henry showed George how putting
the `pi' mark on the 'C' scale of his
sliderule by the '5' on the 'D' scale put
1 on the 'C' scale opposite `6.28' (approximate value of 2-pi) on the 'D'
scale, and then that '6' on the 'C' scale
came opposite 3.77 on the D scale.
"More precisely," he said, "it's 377
ohms."
"It's making sense now," George
said. "I could follow the part that
showed that maximum voltage ap-
peared at zero current, because that
was where current was changing fastest.
It was how the 2 -pi got into the relationships that bothered me. That
whistle will be blowing anytime now,
to summon me back to work, so I must
reserve the getting of capacitive reactance straight for another time. Then
there's that `operator -j' bit. I never did
understand that, although guys who did,
seemed to do some pretty cute tricks
with it and save a lot of time."
Just then the whistle did blow, so
.
they parted for the time being.
it.
"Now," said Henry, if the angle is
small, as it is when it's crossing from
negative to positive, near zero, the hypotenuse is the same as the radius, and
that little bit of `opposite' and the little
bit of circumference are the same thing,
for the time being, aren't they?"
George could see this, so Henry
switched his attack and drew out a sine
wave. "So the rate at which the sine is
changing, where it crosses the zero line,
is the same as the rate at which the
angle is changing, when you use circular measure, instead of degrees."
George did not say anything, so
Henry went on.
"Now, if this rate of change did not
change, how big would the sine be,
by the time you completed a circle, or
period of some frequency?" And he
drew a complete sine wave, with a tangent going on up.
"Two -pi?" suggested George.
"Right. Now remember that change
of current is what causes voltage, in
an inductive reactance. Maximum
change is where the sine wave crosses
the zero line, as shown by maximum
slope at that point. And extending it
like this shows that, if this rate of change
kept up for the whole period-of whatever the frequency-the change would
be 2 -pi units."
"Come again," said George, "I'm not
quite with you."
"Suppose," said Henry, "the maximum current, at the peak of the sine
wave, is
amp, and the frequency is
1
Hz, or 1 cycle every second. Then
the rate of change where the current
crosses the zero line, is 2 -pi amps per
1
second."
"Daylight is beginning to dawn," said
George. "Go on."
"Now, if the frequency is 60 Hz, then
each cycle takes 1/60th of a second, so
the rate of change, where the current
crosses the zero line, is 2 -pi times 60,
times the maximum current at the peak
of the sine wave."
"Got it," said George. "So Henry
will have a reactance of 2 -pi times 601
AUDIO
OUR 25th YEAR
APRIL 1972
When Choosing A Hi-Fi System
Many hi-fi dealers sell systems under
their "own name" brands. Which is
fine. You'll probably save money with
one. And with Maximus made
speaker systems and other
Hallmarked audio components,
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Indeed, dealers, men whose livelihoods depend upon their "sound"
judgment, prefer to use Maximus
stereo equipment in their signature
systems. It assures them of conformance to the best principles in
hi -fidelity, trouble -free performance
... as well as very satisfied customers.
Yes, when your dealer carries
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he's got "sound" judgment. And
when you buy Maximus, you get
"sound" value. But don't ask for it by
name. Simply look for the Maximus
Hallmark. It will probably be the
most essential component in your
"own designed" hi-fi den or home
studio.
'on
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ur
name!
e
Maximus receivers and head sets are designed,
developed & engineered to meet
the same high standards of all
Maximus components.
All Maximus and Maximus made systems
warranteed by Maximus and may be
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our Hallmark.
(M)are
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SODUD
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Garden Cin< N.Y MAXIMUS WEST, Gardena, Calif
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23
JÌVIICROPHONES - Quo Vadis?
James H. Kogen*
Electret Condenser
Transducers for Sound Reinforcement Microphone Applications
A Comparison of the Dynamic and
be very sophisticated in the art of microphone design to discover that there is'no panacea for
all problems. Of necessity, any practical design is to
some degree a compromise. The best microphones are those in
which the most important characteristics have been optimized.
What constitutes the "most important characteristics" will
differ depending upon the application. A microphone that is
optimum for one application may not be so for another. To
make a fair and honest comparison of microphones, we must
consider the application and base our analysis on those characteristics that are significant for the situation being studied.
The selection of a microphone for a given application is
ultimately made by the user. The engineer designing a microphone can only anticipate which features will be most
important in determining that selection. His choice of features
must be based on a thorough analysis of the many design
variables and possible compromises. This requires a careful
evaluation of all the pertinent characteristics of available
transducer types and acoustical designs, consideration of
special features, and a thorough study of the many techniques
of mechanical construction. Ultimately, his design will be
based upon what he conceives to be the best combination of
all of these characteristics to satisfy the requirements of the
intended application.
A comparison between the electret condenser transducer and
the dynamic transducer must take into account many factors.
In this article we will discuss these factors, particularly as they
apply to microphones for use in sound reinforcement.
Emphasis will be placed on identifying the important factors
by which a comparison of transducer types can be made. The
conclusions as to which microphone is most advantageous for
a given situation will be left to the reader.
The electret condenser transducer is an entirely feasible
device for use in microphones. This transducer must, however,
be judged by the same standards applied to dynamic, ribbon,
ceramic, and other types of transducers commonly used in
microphones. As stated previously, no transducer offers a
panacea. The successful use of the electret condenser transducer will depend upon its particular features and limitations
and the way in which these relate to the application of the
microphone.
A comparison of the electret condenser transducer and the
dynamic transducer, in general purpose sound -reinforcement
microphones, covers a very broad range of applications. We
will not at this time consider applications such as professional
recording and broadcast, mobile communications, and laboratory test microphones. Clearly, the conclusion reached
with regard to sound -reinforcement application might not
apply for these other applications since the emphasis may be
on different characteristics.
ONE NEED NOT
Complexity of Microphone Evaluation
When one considers the details, the evaluation of a microphone is a complex matter, and this is particularly true for
directional microphones. There is no simple overall criterion
of performance that describes the quality of a microphone;
there are many criteria for making a judgment and each must
be considered separately. Consider the following characteristics
by which a microphone can be judged.
1. Sound Quality. Several factors affect the sound quality of
a microphone. These factors include the frequency response,
the polar response (the relative sensitivity of the microphone
in all directions), and the distortion at all sound-pressure
levels, from the minimum to the maximum to which the microphone will be subjected. Although these parameters can all be
measured with great accuracy, our ability to relate these
parameters in detail to the subjective sound quality is still
quite limited. As a result, in addition to making the laboratory
measurements, we must also make an evaluation based on
listening-which of course is entirely subjective.
2. Extraneous Noises. Since microphones are designed to
respond to minute changes in sound pressure measured in
microbars (a microbar is one-millionth of barometric pressure
or 14.7 x 10' psi), they are often sensitive to other kinds of
mechanical energy input as well. Structure -borne noise can be
very disturbing in many applications. When a microphone is
held in the hand, for example, a variety of characteristics
become important, such as cable noise, frictional noise caused
by rubbing the hand or clothing against the microphone, and
"thump" noise when the microphone is placed on a floor
stand. Such noise can be a very significant factor in judging
the quality of a microphone.
Another type of extraneous noise is the "pop" that often
occurs when a user expresses the letter "p" or "t." In closetalking applications, excessive "pop" sensitivity can make a
microphone practically unusable.
A third type of extraneous noise is that produced by wind.
In outdoor applications, the relative sensitivity of a microphone to wind noise may well determine whether or not the
microphone can be used.
3. Reliability. A microphone with a multitude of superb features, but with poor reliability, is essentially worthless. Sound reinforcement applications require reliability often under
conditions of severe abuse. We have seen microphones swung
by their cables and dropped on floors on many occasions. To
qualify as a reliable sound -reinforcement product, a microphone should be capable of being dropped on a hardwood
stage without deterioration of performance.
Other factors related to reliability are humidity and temperature. Sound -reinforcement microphones are employed
outdoors in sub -zero weather and in the heat of a tropical
sun. They are used in arid desert regions as well as in highly
humid atmospheres.
4. Output Level and Signal -to -Noise Ratio. Output level is a
significant factor because the signal-to-noise ratio of the system depends upon the output of the microphone in relation to
the noise of the system (usually as determined by the input
'Vice President, Development and Design Engineering, Shure Bros., Inc.
AUDIO
24
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OUR 25th YEAR
APRIL 1972
DIRECTION OF
DIAPHRAGM
MOTION
f-.
FRAME
VOICE COIL
MAGNET
DIAPHRAGM
CROSS-SECTION
DYNAMIC TRANSDUCER
RL:
LOAD RESISTANCE
Rq
COIL RESISTANCE
=
are:
Eg:GENERATED VOLTAGE
SOUND PRESSURE
P
:
FUNCTION
OF
f (P)
=
=
SOUND PRESSURE
RL
Eg
Rg 4-
-
f (P)
Fig. 1-Equivalent electrical circuit of
a
dynamic transducer.
BACKPLATE
SPACER
THRU
AIR PASSAGES
BACKPLATE
DIAPHRAGM
1
OUTPUT
CROSS-SECTION CONDENSER TRANSDUCER
E
P. SOUND PRESSURE
E. BIAS VOLTAGE
Cg
V,
Cg:VARIABLE CAPACITANCE OF
TRANSDUCER FUNCTION OF
SOUND PRESSURE =f(P)
RL=LOAD RESISTANCE
V1 :INPUT VOLTAGE OF LOAD
V1=f(E,Cg)=CONSTANT
Fig. 2-Equivalent electrical circuit of
a
X
P
condenser transducer.
stages of the mixer or preamplifier). A higher output level
from the microphone can be advantageous in improving the
signal-to-noise ratio. However, an excessively high output
level may overload the input stages of the mixer or preamplifier. This means that the output level must be designed to
consider peripheral equipment as well as the internal design
of the microphone itself.
These are just a few of the factors that must be considered
in evaluating a microphone. Each factor must be considered
in detail, and specifications, where possible, must be .assigned
to assure proper performance. The selection of a transducer
must then be made in terms of how that transducer performs
for each and every one of these specifications. As we stated
initially, no transducer offers a panacea. Each transducer has
its own particular features and we must select the device that
best suits our application requirements.
In the remainder of the article, we will first describe the
operating principles of the dynamic and the electret condenser
transducers, and then we will compare the two on the basis
of a number of important specifications. These specifications
include power supply requirements, frequency response, polar
response, handling noise, "pop" and wind noise, reliability,
output level, distortion, and transient response.
Operating Principles and Major Characteristics
The following is a very brief review of the principles of
operation and major characteristics of the dynamic and electret
condenser transducers.
The dynamic transducer operates as an electrical generator.
A coil of wire (the voice coil) is attached to a metal or plastic
AUDIO
OUR 25th YEAR
It is self-generating and requires no external power supply.
has a low internal impedance in the range of 25-1000
ohms at all frequencies in the audio spectrum.
3. As compared to the condenser transducer, it has relatively
high diaphragm -coil mass.
Both the standard and electret -type condenser transducers
convert acoustical energy into a variation in electrical capacitance. This variation occurs when the diaphragm is moved by
a sound pressure, thus changing the distance between the
diaphragm and the backplate. This capacitance change is
reflected as an electrical output in a circuit, such as that
shown in Fig. 2. The microphone acts as a varying series element in this circuit. (As in Fig. for the dynamic transducer,
this circuit is simplified in order to show the relationship between the acoustical input and the electrical output.) The
equation relating output voltage to acoustical input is also
shown in Fig. 2. In an electret condenser transducer, the bias
voltage results from a permanently stored electrical charge
in the transducer; conventional condenser transducers require
an external voltage supply.
Characteristics of the electret condenser transducer pertinent
to later discussion are:
1. It is a self-generating device requiring no external power
supply.
2. It has a very high impedance since it is a capacitor of a
few hundred picofarads minimum and requires a preamplifier
located physically close to the transducer.
3. It has minimum mass for a diaphragm -type transducer
in that nothing is suspended from the diaphragm.
1.
2. It
INPUT VOLTAGE OF LOAD
(e.g. AMPLIFIER INPUT)
V1
diaphragm that moves in response to an input of sound energy.
The coil is placed in a magnetic field and a voltage is produced
when there is relative motion between the coil and the magnetic field. The dynamic transducer is a self-generating device
that requires no external source of power. The equivalent
circuit and the equation that relates output to input, shown in
Fig. I, is highly simplified and presented to indicate the steadystate relationship between sound input and electrical output.
The three significant characteristics of the dynamic transducer pertinent to much of the discussion later in this article
Comparison of Transducers
1. Power Supply Requirements. While both the electret condenser and the dynamic transducer are self-generating devices,
there is a considerable difference in application in that the
former is a high -impedance device and the latter has a relatively low impedance. It is standard practice to employ low impedance dynamic microphones with cables of hundreds of
feet in length without significant problems with hum pickup
and deterioration in frequency response. This is accomplished
without preamplification at the microphone location.
On the other hand, the high impedance of the condenser
microphone necessitates the use of a preamplifier in close
proximity to the transducer element. In practical application,
the best solution is to build the preamplifier into the microphone and provide either a battery or an external power supply
to energize this amplifier.
An external power supply provides a suitable solution but
does mean that this extra element must be included in the
system or, alternatively, d.c. voltage must be made available at
the input terminals of the microphone amplifier. The latter
arrangement provides the neatest solution, but at the present
time, sound -reinforcement equipment is not normally provided with such a voltage source. As a consequence, if the
extra element (the external power supply) is to be avoided,
an internal power source must be provided, which means a
battery in the microphone.
When a microphone incorporates a battery, one must immediately be concerned with battery life. It is possible to
design a preamplifier with current drain so low that the battery
25
APRIL 1972
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AmericanRadioHistory.Com
+20db'-0db
-20db
I
20
100
1000
FREQUENCY IN CYCLES PER SECOND
NIMIN
10000
+20db
0db
-20db
-40db
-60db
-B0db20
100
10000
1000
FREQUENCY IN CYCLES PER SECOND
+20db
-0db
- 20db
L
20
100
10000
1000
FREQUENCY IN CYCLES PER SECOND
Fig. 3A-Free field axial response of a professional quality
omnidirectional dynamic microphone. B, Free field axial
response of a professional quality omnidirectional condenser
microphone. C, Free field axial response of a 1/2 -in. laboratory
condenser microphone.
life will be quite long. The life of a battery may vary over a
considerable range, depending upon the normal quality variations of batteries and upon the temperatures to which they are
subjected. The life of a battery might be as high as 10,000
hours or a little over one year. However, the variation in life
is very large and might extend from as little as a few months
to many years.
The major point of consideration here is that although
battery life can be reasonably long, the battery is still a replacement item that must be maintained. A dead battery
means a dead microphone. A weak battery may mean a
marginally operating microphone. A leaky battery could mean
a damaged microphone. The dynamic microphone does not
have this problem. The electret condenser transducer must
offer features to overcome this disadvantage when compared
to the dynamic transducer.
2. Frequency Response. As we have stated, the frequency
response of a microphone presents only a rough indication of
the sound quality. It is nevertheless a standard by which
microphones are compared and must be considered as a very
important basis of comparison. In the following, we will
consider low frequency response extension, high frequency
response extension, and mid -frequency smoothness.
In terms of low frequency response extension, the condenser
transducer potentially has an advantage. Through the use of
very high impedance preamplifiers, this transducer can be
made to operate at frequencies well below the low end of the
audio range (20 Hz). Dynamic transducers can be made to
operate at very low frequencies also, but in order to achieve
such response, a compromise must be made that tends to
make the microphone more sensitive to handling noise. The
advantage of response below 50-100 Hz is of questionable
value in sound reinforcement, although this potential advantage of the condenser element might be useful in other
applications.
In terms of high frequency response extension, we cannot
state with certainty at this time that either transducer has an
advantage insofar as audio frequencies are concerned. Figures
3A and 3B are response curves of two popular omnidirectional
dynamic and condenser microphones. Both of these types
exhibit response to 20 kHz within a few decibels. Figure 3C
is the response of a laboratory -type condenser microphone
with frequency response extending well beyond 20 kHz. For
sound -reinforcement applications, both types of transducers
have the capability of satisfactory high-frequency response.
Smoothness of response in the mid -region can be accomplished by both transducers, as shown in Figure 3. The
condenser element might have an advantage in having fewer
small variations in its response curve, but the variations in a
good dynamic microphone response would be in the order of
2 dB or less, and it is doubtful whether this would affect the
sound quality sufficiently to be detected when the two types
of transducers are compared subjectively.
In our judgment the frequency response possibilities of the
two types of transducers, for use in sound reinforcement, are
similar. We must, however, remind the reader of the point
made previously with regard to frequency response and subjective sound quality. Frequency response does not tell the
whole story with regard to sound quality. The frequency
response of a dynamic and electret condenser microphone may
be similar, but the sound quality could differ because of other
factors.
3. Polar Response. Theoretical analysis indicates that neither
the dynamic nor the electret condenser transducer has an
advantage with regard to polar response. This characteristic
is primarily a function of the acoustical design of the microphone in conjunction with the transducer. Measurements on
existing microphones have corroborated this theoretical
analysis.
The unidirectional dynamic microphone requires a mass controlled transducer having a relatively low fundamental
resonant frequency. The condenser microphone requires a
resistance-controlled transducer having a resonant frequency
in the mid-range. The acoustical networks required to achieve
unidirectional characteristics can be similar for the two transducers, and there are a variety of networks available for either
type. Ultimately, we may discover that a particular network
in conjunction with one or the other of the transducers offers
some practical advantage. At the present time, however, this
is not the case, and the two types of transducers are comparable
with regard to polar response of the microphone in which
they are employed.
4. Handling Noise. This is a characteristic that is often overlooked but one that can be very important. A microphone is
26
AUDIO
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OUR 25th YEAR
APRIL 1972
When we say o headphones
are out of ` is world
..we can it.
.
NASA chose Sennheiser
headphones for its
Skylab astronauts to use in
their 56 -day earth -orbit mission.
But people prefer them
for down to earth reasons.
NASA _elected us ...
but you don't have to go into
orbit for comfort
Out .n space or here on earth, the
last -hing you ware is to be uncom-
fortable Whether you're relaxing
with yoir favorite music or com-nunicaf ng with a ground tracking
station.
h
one good reason so many
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HD 414 "open -aire" headphones.
Even f they weren't the lightest
hey are), they're not bulky,
(wf
ch
anc do-l't need uncomfortable airtight SE als to get good sound.
$150.00 sound
at $36 35? Ask
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WORLD!
Accorcing to -he October,
issue, our HD 414
has "the best sound of any
1971
dynamic phones"
-
based on
factors like frequency response,
transient response, sensitivity and
listening tests. In the article's headphone comparison chart, the only
really comparable headphone
maker's sets were priced at $95.00
and $150.00 apiece! (As if that
weren't enough, we 'were also rated
most comfortable.)
Isolation or
Communication?
The choice is yours. With "open aire" headphones, you hear as
much as you want of your surroundings. Or as little: a twist of the
volume control and you're
effectively alone!
A"superior...natural"
headphone? Sounds
like HIGH FIDELITY
feels that way!
They pointed out our
headphones combine "the
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superior close-up quality characteristic of headphone sound" with
"the freedom and naturalness of
loudspeaker listening." What's
more, they felt that the HD 414 is
cooler to use, "allowing body heat
to dissipate more readily."
Hearing is believing
In this world and out, it seems more
and more people rate Sennheiser
"open -aire" headphones tops. But
all the testimonials in the world
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ears in orbit. At
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500 Fdth Avenue, New York, N.Y-. 10036 (212) 564-0433
VVr',1 Grrnr,rrry
f, ,,,q l'I,1r11
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Check No. 27 on Reader Service Card
i
DIAPHRAGM
SOUND
WAVES
H
TRANSDUCER
ASSEMBLY
H
-
STRUCTUREBORNE
NOISE WAVES
DIAPHRAGM
MOVED BY
TRANSDUCER ASSEMBLY
MOVED BY STRUCTUREBORNE
SOUND WAVES
NOISE WAVES
4-Voltage generation caused by structure-borne noise.
Relative motion between diaphragm and assembly produces
electrical output and can result from either diaphragm or
assembly motion.
Fig.
a unique instrument in
that it must be highly sensitive to the
input of sound energy but should also be insensitive to the
input of structure -borne energy. These are decidedly conflicting requirements. As a general rule, the sensitivity to structure borne sounds will increase with the mass of the diaphragm in
the transducer. The electret condenser transducer unquestionably has an advantage over the dynamic transducer in this
regard. Figure 4 shows a simplified representation of how the
microphone transducer reacts to structure -borne noise. In
order to reduce the effects of this type of noise, it is standard
practice in dynamic microphone designs to introduce a shock
absorber between the outer case of the microphone and the
dynamic transducer. Because of its inherent low sensitivity to
structure -borne noise, the requirement for shock isolation
of the condenser microphone is significantly less than that of
a dynamic microphone. This results in two important considerations.
A. For a given structure -borne noise sensitivity, the cost of
the shock isolation in a dynamic microphone will be higher
than that of a comparable electret condenser microphone.
B. The requirement for shock isolation will add to the size
of the dynamic microphone. Stated conversely, the electret
condenser microphone could be made smaller because of the
simplicity of the shock isolation required. This feature has
merit, for example, in a lavalier microphone or a microphone
mounted on a headset boom. The advantage is less in situations where microphone size is determined by other factors
such as windscreens, pop filters, and cable connectors.
We feel that insensitivity to structure -borne noise can be the
major advantage of electret condenser microphones in sound reinforcement applications.
5. Pop and Wind Noise. Measurements on a large variety of
dynamic and condenser microphones indicate that both transducers are equally susceptible to pop and wind. A reduction
of pop and wind noise must be achieved through the use of
external windscreens and pop filters in either case.
6. Reliability. As stated previously, reliability is an extremely
important factor in comparing products for sound -reinforcement applications. We will consider three factors relating to
reliability: mechanical ruggedness, the effect of humidity, and
the effect of temperature.
With regard to ruggedness, the dynamic microphone has
proved itself over a period of more than 30 years. A properly
constructed dynamic microphone is sufficiently rugged to
withstand the rigors of severe sound -reinforcement applications. The electret condenser microphone has yet to prove
itself. The answer to the question of relative ruggedness will
only be gained through experience over an extended period of
time.
In humid conditions, the dynamic transducer presents no
problem. Care must be taken, of course, to adequately protect
metallic parts, but this is standard practice in all quality microphones. The electret transducer, on the other hand, has
potentially severe problems in humid atmospheric conditions.
High humidity can cause the loss of the electret charge. This
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a
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was a problem in electret devices made several decades ago,
using Carnauba wax, and presents a potential hazard to
modern-day electrets employing plastic materials. Clearly, for
the microphone to be satisfactorily reliable, the electret charge
must be maintained under the extreme conditions often found
in sound -reinforcement applications.
In laboratory tests, our company considers life of 1,000
hours at 100% relative humidity to be a minimum requirement
for any microphone. We have tested several electret microphones that would not withstand this test at room temperature.
Our conclusion is that suitable electrets can be made, but that
humidity still presents a potentially serious problem for the
electret.
In comparing the two transducer types under conditions of
high temperature, we find the onus again is on the condenser
to match the known performance capability of the dynamic.
Dynamic microphones made by Shure are required to withstand storage temperatures from -20 degrees F to + 165
degrees F and must operate within standard performance
specification at temperatures from -20 degrees F to + 140
degrees F. We have found these to be suitable temperatures to
guarantee reliability in performance of the microphone under
field conditions. The electret condenser microphone must, of
course, also be capable of withstanding these extremes of
temperature. The high end of the temperature range will offer
the most difficult problem for the electret, particularly when
combined with high humidity.
An additional factor that must be considered in evaluating
the electret condenser microphone at high temperature is
the effect of temperature on the dry cell incorporated in many
of these microphones. Most alkaline and carbon zinc batteries
will not withstand a temperature of + 165 degrees F for an
extended period of time. We would include the dry cell in
temperature tests to determine whether any leakage of the cell
might damage the microphone. Since the dry cell is normally
easy to replace, we feel that it is reasonable to change to a
new dry cell for subsequent testing after the high temperature
exposure is completed.
7. Output Level. Since the electret condenser microphone
must be supplied with a built-in preamplifier, there is a possibility of providing a very high output level-much higher
than with the unamplified dynamic microphone. Care must be
taken in providing a low -noise preamplifier in order to achieve
suitable signal-to-noise performance. The design must also
consider the problem of amplifier saturation in order to minimize distortion at high sound -pressure levels. The advantage of
a high -output level is somewhat mitigated by the fact that an
excessively high -output level can result in overloading the
input stages of the mixer or amplifier to which the microphone is connected. Typical output of a dynamic microphone
is in the order of -57 dB with reference to one volt per microbar. We would question the value of an output level of greater
than roughly -52 dB because of the probability of overload
in subsequent stages of amplification.
8. Distortion. Dynamic microphones usually exhibit very
low distortion. We have measured a large variety of both
omnidirectional and unidirectional dynamic microphones at
levels up to 150 dB sound -pressure level. Total harmonic
distortion is typically below 1% up to the highest pressure
measured. (As a point of reference, 130 dB sound -pressure
level can cause physical damage to the ears.) Similar measurements on condenser microphones indicate total harmonic
distortion below 2% for the majority of microphones, and
below 1% for the higher quality condenser microphones up
to sound pressure levels of 130 dB SPL. Condenser microphones exhibit a relatively sharp overload point in the range
of 130 to 150 dB SPL, at which level the distortion rises very
rapidly. This type of distortion can he caused by bottoming of
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But your typical 150 watt per channel number is going to clip. Even
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HARMONIC or I.M. DISTORTION less than .25%; typically .01%.
POWER
8
0
ohms.
to .25
FREQUENCY RESPONSE
mHz.
DAMPING RATIO
1,000 to 1, .!1
-0
20 Hz.
-
-
Better than 100 dB
HUM & NOISE
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-
That's not typical either.
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5.0
FREQUENCY=350
Hz
i
I
3/4" PROFESSIONAL
4.0 CONDENSER CARDIOID
I
I
MICROPHONE
EXAMPLE NO.2
}"`"i 3/4' PROFESSIONAL
I.
3.0
I
CONDENSER CARDIOID
MICROPHONE
I
EXAMPLE NO.1
I
2.0
t
t
1.0
.
09
100
110
/
/
I.I°DYNAMIC CARDIOID
MICROPHONE
120
130
140
SOUND PRESSURE LEVEL
150
(dbSPL)
5-Overload characteristic examples of condenser and
dynamic microphones.
Fig.
servomechanisms, and so on, there are several problems in
applying the test to microphones. One problem is that of
creating a standard transient; and at this date, no such standard
has been devised or specified. A second problem is correlating
the results of such a test with other types of measurements
(such as frequency response) and with subjective reaction.
Since no standard test procedure exists, and since there is
little documentation with regard to the significance of transient
response tests, we do not feel that it is proper to make a comparison of microphones on this basis at this time. While one
might easily design a test that will display differences between
two microphones, to be fair one would have to document the
significance of the differences noted. One major aspect of this
documentation would certainly be the subjective differences.
We strongly emphasize that this type of testing must be very
carefully controlled with many variables to be considered. One
cannot make a judgment based on a simple demonstration.
Conclusion
the diaphragm but is normally the result of clipping in the
preamplifier. Figure 5 shows total harmonic distortion versus
sound -pressure level for typical dynamic and condenser microphones.
The two transducers can be comparable in terms of distortion at normal sound-pressure levels and can be suitable for
maximum sound-pressure levels 'formally found in sound -
reinforcement applications. The dynamic transducer is inherently less difficult to control with regard to distortion and
has an advantage in being able to handle extremely high peaks
of sound pressure, which may sometimes occur in "close talk"
applications.
9. Transient Response. At this time, there is no standard test
for transient response of a microphone. While this type of
test is commonly used in evaluating amplifiers, loudspeakers,
In summary, then, we would like to make the following
points. Any comparison of microphone types must consider the
application for which the microphone was intended. Comparison of microphone types is complex and must include all of the
many pertinent characteristics. In comparing transducer types,
one must consider the way in which the total microphone is
designed and built. Either the dynamic or the electret condenser transducer can be employed in a good or bad microphone design.
This article has attempted to describe some of the more
important characteristics per inent to electret condenser and
dynamic microphones in s und -reinforcement applications.
The selection of a micropho e will be made by the user and
will be based on those characteristics that are most significant
/E
to the application.
opening
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Activating Your
Loudspeaker Crossover
Michael W. King
0
in hi -fidelity system design is that
of a crossover network to divide the output spectrum
into portions suitable for high and low frequency
loudspeaker drivers. In the past, this has been achieved with
the use of passive filters, as shown in Figure 1A. The disadvantage of this system is the non -constant input impedance of
a direct-radiator loudspeaker.' A solution to this problem
has been proposed by Ashley and Kaminsky,' employing a
system like that shown in Figure 1B. In this system filtering
is accomplished at low levels and the speakers are driven by
low output impedance buffer amplifiers. Clearly, this isolates
the driving point impedance of the loudspeakers from the
output of the filter; and, in addition, the input impedance of
the buffer amplifier can be made virtually any value of pure
and constant resistance making this system also suitable for
use with passive filters. In addition, it should also be noted
NE OF THE PROBLEMS
A.
LOW PASS
J
etotal
POWER
AMPLIFIER
-
WOOFER
FILTER
SIGNAL
INPUT
that the typical passive network of Figure IA requires
capacitances on the order of tens of microfarads, which
are expensive and difficult to obtain, while the active network
of Figure IB requires capacitors on the order of nanofarads,
reducing the cost differential between the two systems.
Following Ashley and Kaminsky,' a filter as shown in Figure
2 was constructed. This is an asymmetrical third -order network
where the high-pass has a third -order Butterworth characteristic. Here the high-pass is achieved by an active filter and the
low-pass portion is derived by subtraction of the high-pass
signal from the total input signal. This design is of the constant voltage type described by Ashley' and Small,' meaning
that the phasor sum of the outputs of the filter is equal to
some constant in the frequency domain. Because of this, given
perfect drivers and amplifiers, the total acoustic output signal
will be a perfect reproduction of the source material. This can
be demonstrated, as shown below by adding the transfer functions of the high and low pass filters to give the transfer
function for the sum of the outputs.
eHI
eIN
HIGH PASS
eL0
+
eIN
eIN
S3 + 2S2 + 2S +
=
POWER
I
1
(ACTIVE)
POWER
TWEETER
B.
1
+
1
-0.5
(2S2 + 2S + 1)
S1 + 2S2 + 2S +
1
+2S+1
S3+2S2+2S+1
S,
S
+2S
1
1
NETWORK
AMPLIFIER
Fig.
-0.5
WOOFER
AMPL IFIER
FILTER
S3
TWEETER
FILTER
SIGNAL
INPUT
-0.5
-
-Possible crossover-amplifier arrangements.
Thus, this network has a gain of one-half which is constant
with respect to frequency. The filter was designed for a gain
of one-half in order to simplify component values and to
avoid problems caused by excessive levels.
A µA741 operational amplifier was chosen because of its
high gain and wide range of operating voltages. This was
chosen over the popular µA709 operational amplifier because
the 741 requires no external frequency compensation. Supply
voltage of ± 15v was chosen because this was most compatible
2R0
l
eL0
eIN
leLO1
i
0
°HI
IeH1I
R2
0
kilohm
RO
=
10
R1
=
8.79 kilohms
R2
=
7.73 kilohms
R3
=
61.5 kilohms
Co
°HI
eIN
-0.5s3
s3+2s2+2s+1
50
2nfc
4
0
µ.F
90
C
8e1-11
90
eLO
-0.5(2s2+2s+1)
°IN
s3+2s2+2s+I
ee LO
100
---__
10000
1000
FREQUENCY, Hz
80
270
s=J(f)
c
Fig.
2-Active filter network.
Fig.
3-Measured
32
response of I.C. filter network.
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
OUR 25th YEAR
APRIL 1972
The optional everything system.
Quadrasonic. t uadruplex Stereo.
And the double play.
With Panasonic's optional
everything system you start
simple.. With the SC -8700. Then
build up your sound froim. there.
The SC -8700 is a 4-piece music
center with a 4 -channel amplifier.
It has an FM/AM/FM stereo
receiver. A 4-speed Garrard
automatic turntable with a
Pickering V-15 cartridge.' Two air suspension speakers with a 3-way sound reproduction system.
And 60 watts of power (IHF).
Add a pair of SB -170 or
SB -270 speakers; and you get the
sound of QuadruplexTM circuitry.
The second set of speakers
playing the music a fraction of a
second later. The way you'd hear
music in a concert hall. And you
can even get Quadruplex from..
your old stereo records and tapes.
As well as frmcm our FM stereo.
For people who want to get
might inside the music, we have
something special. Quadrasonic.
just add our 3 -track tape deck,
the RS -847U8. And now you
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of sound. One channel from each.
speaker. One speaker might he
emphasizine the string section.
Ore the woodwinds. One the
brass. And one the percussion.
So instead of just listening
to Mahler's Third, you feel like
yDn're the conductor.
The SC-8700 also lets you
make the double play. Something
that's perfect for families with
different tastes in music. With
the optional set of speakers, you
can play Bach on FM stereo in
your room. While the kids listen
to a Beatles' record in their room.
At the same time.
You can hear the whole works
:t your franchised Panasonic
Hi-Fi dealer. The one man who
gives you all the options on haw
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just slightly ahead of our time.
20C Park Ave., N.Y. 100 7. For your nearest *ranchised Panasonic Hi
-i dealer, cal
www.americanradiohistory.com
AmericanRadioHistory.Com
830 331-'971
.
In N.J., 000 962-2805,
1
F-Hz
100.00
125.89
158.49
199.53
251.19
316.23
398.11
501.19
630.96
794.33
1000.00
Table
Co -(µF)
0.07958
0.06321
0.05021
0.03988
0.03168
0.02516
0.01999
0.01588
0.01261
0.01002
0.00796
1
F -Hz
Co -(µF)
0.00632
- 0.00502
- 0.00399
2511.89 - 0.00317
3162.28 - 0.00252
3981.07 - 0.00200
5011.87 - 0.00159
6309.57 - 0.00126
7943.28 - 0.00100
10000.00 - 0.00080
1258.93
1584.89
1995.26
-
-Capacitor values for active filter network.
a constant voltage network and for a third -order low-pass
would have an 18 dB per octave slope for the high-pass. The
disadvantage to this arrangement is that, because of the greater
energy in the low -frequency portion of the spectrum, the
tweeter would be forced to handle considerably more power
because of the lesser stop -band slope, and this might adversely
affect reliability. Furthermore, because of their built-in inductance and reasonably civil behavior above the usual cutoff
frequencies, today's low -frequency drivers are more suitable
for use with a 6 dB per octave stop -band slope.
Component values were selected from Table IV of Ashley
and Kaminsky's paper,' which is reproduced here as Table 1,
for a crossover frequency of 1584.89, which is suitable for an
8 -in. woofer. The values specified by Ashley and Kaminsky
are:
Ro = 10
Kilohm
R
= 8.79 Kilohm
R2 = 7.73 Kilohm
R3 = 61.5 Kilohm
Co = 5.02 Nanofarad
Since these values are not readily available, some change was,
necessary as shown below.
Ro = 10
Kilohm
Ri = 8.79 Kilohm
R2
= 7.8 Kilohm
R3 = 60.7 Kilohm
i
with the commercially available integrated -circuit power
amplifiers and it was intended that both filter and buffer
amplifiers could be powered from a common supply.
For this network, the slope of the high-pass characteristic in
the stop -band is 18 dB per octave and the phase goes from
-180 degrees in the pass -band to 90 degrees in the stop -band,
with -45 degrees at the crossover frequency. For the low pass,
the stop -band slope is 6 dB per octave and the phase response
goes from -180 degrees in the pass -band to -270 degrees in the
stop -band with approximately -180 degrees of phase shift at
the crossover frequency. Ideally, perhaps, the phase shift in
the pass -bands would be zero degrees; however, the operational amplifiers require an additional -180 degrees for
stability because of the feedback employed. Note also that
a filter could have been synthesized by deriving the low-pass
and subtracting to obtain the high-pass. This would also be
Co
TUD20 4
nlaheS
gt'eat found
twice
= 5.0 Nanofarad
This was found to have a negligible effect on the actual
response, as demonstrated by the fact that the measured -3 dB
point of the high-pass signal (crossover frequency) was 1.55
kHz which is in error by less than 5 percent.
The measured frequency response is as shown in Table 2
and Fig. 3. We note that this is a very flat curve without unexplained bumps and glitches that sometimes plague passive
a&
good:
You have 4 channels in
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Mag.,
-Hz
dB
40
50
60
80
100
120
140
170
200
250
300
400
500
600
800
1000
Phase,
degrees
-50
-50
-50
-50
-50
-50
-50
-50
-52
-47
-42.2
-34.8
-28.9
-24.3
-17.0
-11.3
Mag.,
Phase
Freq.,
Mag.,
dB
0
0
0
0
0
0
0
0
0
0
0
degrees
-180.0
-180.0
-180.0
-180.0
-180.0
-180.0
-180.0
-180.0
-180.0
-180.0
-180.0
-180.0
-178.8
-177.7
-177.1
-178.8
-Hz
dB
0.1
0.2
0.4
42.1
27.4
6.9
1.1
2.0
eu
eni
elo
eld
Freq.,
networks of this kind. Also note that the stop -band slopes and
phase response are as predicted by myself, and Ashley and
Kaminsky.'
In short, it is felt that the active filter network is. a good
performing, easy to realize alternative to the passive networks
used in the past. In addition, given the relatively more common component values used as compared with a passive network for a similar function and the low cost of integrated circuit operational amplifiers (the µA741 is available for less
than $1.00), the cost differentialrshould not be excessive. it
-7.2
-4.3
-2.3
-1.0
1200
1400
1700
2000
2500
3000
4000
5000
6000
8000
10000
12000
14000
17000
20000
25000
Table 2 -Measured response of
Phase,
degrees
-12.7
-33.4
-62.9
-81.9
-.4
-.2
0
0
0
0
0
0
0
0
I. C.
dB
2.9
3.5
3.6
2.8
-104.1
-118.4
-135.6
-145.2
-150.1
-158.3
-163.1
-166.7
-169.0
-171.4
-173.1
-179.4
-.1
-.1
Phase
degrees
-184.0
-192.7
-206.7
-217.6
-229.5
Mag.,
1.4
-238.2
-245.5
-250.0
-251.8
-253.7
-255.9
-258.5
-261.9
-.1
-2.6
-4.5
-6.0
-8.0
-10.6
-12.3
-13.8
-15.8
-17.5
-20.0
active filter.
References
Beranek, Acoustics, (McGraw-Hill, New York, 1954).
Kaminsky, "Active and Passive Filters as Loudspeaker Crossover Networks," J. Audio Eng. Soc., 19, 494 (1971).
3. J. R. Ashley, "On the Transient Response of Ideal Crossover Networks,"
J. Audio Eng. Soc., Vol. 10, No. 3, 241.
4. R. H. Small, "Constant -Voltage Crossover Network Design," Proc. I.R.
E.E. Australia, 31, 66 (1970).
5. J. R. Ashley and L. M. Henne, "Operational Amplifier Implementation
of Ideal Electronic Crossover Networks," J. Audio Eng. Soc., 19, 7 (1971).
1. L. L.
2. J. R. Ashley and A. L.
Not 'all legends are elusive.
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.
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Fke
From
people who
LrouhP' you
Franz U5z1"?
George W. Tillett
f'
Editor's Review
tg
.
sAn-`,
7,':*
MR!
u+',er *ºr,
t. .r. Ite...ï
<..+
=
,
f w.
I had been
intrigued
by a series
of advertisements
for Hungarian
loudspeakers
appearing under
the above heading
in some trade . . .
HAD BEEN INTRIGUED
by a series
Iof advertisements for Hungarian
loudspeakers appearing under
the above heading in some trade
journals and so, when I was invited to
join a party visiting Hungary, I jumped
at the chance to find out what "the
people who brought us Franz Liszt"
could have in store for us. (In passing,
I notice that Deutsche Grammophon's
European advertisements read "From
the people who brought you Valhalla."
It's up to the Italians now....) Anyway,
before I bring you Hungary, I want to
"make one thing perfectly clear." I have
experienced both Fascist and Communist states at first hand and I dislike
any form of totalitarian government.
Our free enterprise system is far from
perfect but it gives more freedom and
a higher standard of living than obtains
anywhere in the world. That said,
I must say that I was pleasantly surprised to find more freedom in Hungary
than I expected and, although there is
no political freedom, the regime is
probably more liberal (in the best
36
sense) than any in Eastern Europe. The
standard of living is low by our standards, but even so it is better than that
in surrounding countries. Conditions
have improved enormously since the
abortive (counter*) revolution of 1956
and Hungarians are now free to travela privilege granted to citizen groups
in the Soviet Union. We stayed in
Budapest which is a very beautiful city
with many historical buildings. Much
damage was caused during the war, but
considerable rebuilding is in progress.
Unfortunately, all the shops-with the
exception of tourist centers-close
promptly at 6:00 p.m., after which the
good people of Budapest are swallowed
up by the subway and the yellow caterpillar -lines of streetcars, leaving the
town as deserted as Philadelphia on
a Sunday morning. Well, not quite
because there are 14 theaters and a
multitude of restaurants-and some
night clubs! It is a city of contrastsincredibly ancient public telephone
boxes outside a streamlined modern bus
'Take your choice.
AUDIO
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OUR 25th YEAR
APRIL 1972
mounted on a
rod. Output from the microphone is
fed to a level recorder fitted with contacts arranged to switch on one of the
lamps when the output of the microphone is within one of the relatively
narrow level ranges plotted. A camera
with open shutter is used to photograph
the sound field variations which appear
as isobars. The system was the subject
a microphone which is
Typical EAG control desk.
station, an ultra -modern international style hotel near gems of baroque architecture, and posters about America
and Vietnam next to advertisements for
Coca-Cola and the latest Streisand
movie. In spite of anti-American propaganda (mainly confined to the Vietnam
issue), I met nothing but friendliness
and goodwill from people at all levels.
Every morning our party of 18 plus
two interpreters were picked up at the
crack of dawn by "Icarus 108-40"a comfortable bus which in due course
decanted us at a factory. Here we would
be greeted by the staff and, after
sampling the wine, we would look at
the production lines, laboratories, and
so on. Most of the organizations made
loudspeakers but one in particular,
ElectroaKusztikai or EAG, made a
,
great variety of electronic equipment
as well. The range included tape recorders, language laboratories, interpreter systems, communication systems, airport tape monitors, studio
control desks, microphones, headphones, high power amplifiers, outdoor
speakers, and acoustic panels. There is
even a range of equipment called "Beat
Set" designed for rock groups!
One of the cassette recorders demonstrated, used a noise reduction circuit
called EX -CO, which appeared to be
similar to the Dolby system. I could
get no circuit details or figures beyond
the claim that the S/N was improved
by 10 dB-but it certainly sounded
impressive. Another model handled
both reel-to-reel and cassette tapesnot unknown here-but this model
allowed for completely independent
AUDIO
OUR 25th YEAR
operation. It is mono only and the
frequency response at Th ips is given
as 40 to 16k Hz + 3, -5 dB with a signal
/noise ratio of 45 dB. Motorola and
RCA transistors are used extensively
but some are Hungarian made, as were
the tape heads, plastic mouldings, and
cassettes themselves. The studio desks
appeared to be of a high standard with
galvanometer type VU meters and upto-the-minute low -noise circuitry. Typical figures were -125 dbm for microphone input and -74 dB for line. It
was stated that 300 had been made
during the past year and most of these
went to the Soviet Union.
Videophone has several factories,
employing a total of 10,000 people,
and we visited two locations-both over
50 miles from Budapest near Lake
Balaton. One produces all the woodwork and the other is devoted to
electronics and loudspeakers. The
acoustic labs were well-equipped and
I was impressed with the amount of
research devoted to cone materials,
absorption
and
acoustics,
room
properties of materials. One of the
novel devices developed here was an
ingenious method of plotting a sound
field by using colored lights. Five lamps
of different colors are fixed close to
Showing sound field
through
a
penetrating
door at 100 Hz.
of a paper presented to the 7th International Congress of Acoustics, Budapest, 1971.
Most of the lab instruments were
made in Hungary but I also noticed
equipment by Marconi, B & K, Hew-
lett-Packard, Solartron, and Radiolab.
Loudspeakers by Wharfedale, Tannoy,
and Electro -Voice were also seen in
one of the labs. Loudspeaker magnets
used were either Alnico 5 ring magnets
or ferro -ceramics made in other
Hungarian plants, but speaker baskets
and cones were made in this particular
factory. I should mention here that
Videotone and EAG are part of the
same group and like the rest of
Hungarian industry, controlled by the
State.
The assembly lines at Videotone were
like others we saw-reasonably efficient but (to our eyes) they did things
the hard way. For instance, where we
use' electric or air -operated tools to
insert screws, they use hand drivers.
We use automatic sweep generators
and all kinds of production aids to
reduce costs but they get the same
results in the end because of the rela37
APRIL 1972
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tively low overall production costs.
For instance, girls on the assembly
line get 8 to 9 forints an hour for a
48-hour (5' day) week. At the present
rate of 30 forints to the dollar, this
is still pretty low but the cost of living,
subsidies, and fringe benefits must be
taken into account. For those interested,
some comparative figures are given at
the end.
Several speaker systems, ranging
from single units in small enclosures
to studio monitors, were demonstrated.
Amplifiers included a McIntosh and a
Videotone with an AR turntable and
a Pickering V-15 cartridge. At least,
I believe it was but I cannot be certain.
Sound quality varied and I hesitate
to pass judgment as the program
material was not that good. I liked a
small system, the 132, which used a 5 in. bass unit with a 4-in. treble speaker.
The bass unit had an unusually large
magnet-about 22 ounces, I would guess
-and the cone surround was of soft
rubber. Flux would be around 12,000
lines and the voice coil looked just
over an inch in diameter. At the other
extreme, I liked the HEC -11 studio
monitor which used a 12 -in. bass unit
with four 5 -in. speakers. Each speaker
system had its own built-in 50 W amplifier which incorporated narrow -band
adjustable filters. The enclosure itself
is vented and the system could handle
a great deal of power with low coloration. But the speaker that attracted
speaker used in the D-132
system.
Bass
most interest from our group was the
Ultra -1, already available here and in
Canada. It uses nine 41/2 -in. double cone speakers in an enclosure measuring
13 in. high, 23 in. wide, and 11 in.
deep. Eight speakers are mounted at
the back and one at the front. However,
unlike similar systems, placement is
optional and the enclosure can be
turned around so the eight units face
the front. In other words, the stereo
image can be diffuse or sharp according
to the room acoustics or listener's
preference. Price here is $399.00 a pair
and we hope to review this model in
the not-too -distant future. Incidently,
Videotone makes a very big range of
radio receivers as well as TVs-both
monochrome and color.
Qualiton and Hungaroton records
have a worldwide reputation and a visit
to their studios was one of the highlights of our busy week. Present production is over three million discs
a year, of which over 50 per cent is
classical. Although accent is on Brahms,
Hayden, Bartok, Beethoven, and
Mozart, special attention is also given
to young contemporary composers.
Up to the present, no quadraphonic
discs have been made and I got the
impression that the studio manager
regarded the whole idea with some
suspicion. . . . Recorders were Studio
Telefunken but these will be replaced
with EAG models later this year. Monitor speakers were Goodmans Tri-Axials
mounted in corner enclosures. It was
noted that the customary 8 and 16
channel recorder/mixing units were
absent, but we were told these would
be installed soon. Which may be
a
The woodwork factory was set in
rural surroundings some miles away
and we were all impressed by the high
standard of craftsmanship. The majority
of cabinets were spray -finished in a
high gloss polyethylene which is not
too popular here but many other
finishes are available.
The Budapest broadcasting network
comprises two AM stations in the
medium frequency bands, a short wave,
and a FM stereo transmitter. We visited
the studios near the center of the town
and were somewhat surprised to learn
that cameras could not be taken inside.
The 1956 revolution started here and it
would seem that the authorities are still
a little nervous. Be that as it may, we
were received with typical Hungarian
courtesy and shown the studios and
control rooms. The director told us that
they recorded in four -channel but had
made no broadcasts in this medium so
far. Microphones were AKG and Neumann and combinations of spaced and
MS were used for quadraphonics.
Studio equipment was EAG with
Hungarian EMG tape recorders which
looked very similar to the Studer.
Monitor speakers were larger versions
of the HEC -11 with a 15 -in. bass unit
crossing over at 650 Hz to eight 5 -in.
speakers arranged in two semi -circles.
38
pity....
One of the most interesting experiences was watching a musician-engineer
(their
description)
editing
pops,
crackles, and other noise from a tape.
There he was, sitting at an editing recorder, snipping off tiny pieces of tape
and joining up. The tape was an old
one-Mengleberg
conducting
the
Amsterdam Concertgebouw playing
Bartok's Second Violin Concerto with
Zoltan Szekeley. It was made way back
in 1939 and the performance was a
brilliant one. Although the engineer musician had a big collection of tape
ends, he estimated that the total musical
loss would only be a second or two.
(Tape speed was 15 ips.) A very tedious
job, though, but rewarding in the
artistic sense.
O
C9
o
O©
O
After a brief look at the new sound
system at the National Theatre, we went
to the Erkel Opera House to hear a
Hungarian Operetta by Ferenc Erkel.
I thought the staging was excellent
and the orchestra gave a really polished
performance. Acoustics were very good
AUDIO
OUR 25th YEAR
APRIL 1972
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and most of the audience got about 90
per cent direct sound (sorry about that!).
Seats were somewhat cheaper than
Broadway standards at 25 cents!
So, apart from speeches at the
Chamber of Commerce and a visit to
a state wine farm, which I refuse to
discuss, thus ended a most exhausting
but enjoyable week. And now for some
conclusions.
*The EAG group already export some
85 per cent of their products but
there is no doubt that they could sell
studio and communications equipment
in the U.S.
*The speaker systems are competitively
priced and I am certain that in this
area the Hungarians will pose a serious
challenge to Japanese and U.S. made
products-and possibly to Western
European manufacturers too.
*I see no reason why we cannot trade
with Hungary. Ultimately this would
raise their standard of living with far
reaching results. I have the impression
that the Hungarians want to look west
as well as east. Of course, trade has
to be two way, but they are already
importing American transistors, instruments, and many other items. The mare
dollars they earn, the more they can
buy from us.
Finally, I would like to thank Mrs.
Edith Vezér of Elektromodul, the
Hungarian trading company, and Mr.
G. Simonyi from Ultra-Tone of
Canada, who organized the trip.
Here are some comparative prices
(30 forints to the dollar):
Salaries: Top managers, executives,
chief engineers
5000 forints/mo.
Middle echelon managers, engineers,
supervisors
3000 forints/mo.
Semi -qualified engineers, manual
workers
2000 forints/mo.
Assembly workers, girls
8 to 9
forints per hour (48 hour week).
Prices (selected at random):
Cars, VW,
110,00 forints
East German (DDR) mini 60,000
forints
TV, B&W, 18 in.
8,500 forints
Men's suits
750 forints
Leather shoes
500 forints up
Suede shoes
250 forints up
Cassette recorder
300 forints
12-in records
35 to 60 forints
Bread (subsidized)
3 forints/kilo
Coffee
32 forints/6 oz. app.
Tea
30 forints/6 oz. app.
.
...
Beef
50 forints/kilo
25, up to
Dinner in a restaurant
100 forints for a gourmet meal
One engineer told me that the
Hungarian bank has a "car winning"
deposit scheme. Participants stand a
....
,
chance of winning a car by a lotterybut the snag is-no interest is paid!
Normal interest rates are 3 per cent for
three months minimum, and 5 percent
yearly-capitalist thinking which would
make Karl Marx turn over in his London grave!
Rents are cheap and vacations in
group centers are heavily subsidized.
Books are relatively inexpensive, so
are theater prices as noted previously.
Finally, some advice for those who
will be visiting Hungary.
*The food is magnificent, so don't go
if you are on a diet and have no will
power.
*The wine is very potent, so be careful.
*Bring Alka-Seltzer tablets.
Dreaming about a pair
of $300 condenser
microphones?
Think seriously
about these:
}
$39.75*each
Model 1710 Electret Condenser
Omnidirectional Microphone
All of the great condenser advantages are here without compromise.
Flat, extended range, excellent transient response, high output, low noise,
and ultra -clean sound. But the new E -V electret condenser microphones
need no high voltage power supply. Just an AA penlite battery to operate
the built-in FET impedance converter. The result is studio performance
without complications and at a dramatically lower price.
There are 4 new E -V electret microphones, including cardioid models,
from $39.75 to just $75.00, audiophile net. Second -generation designs
with unusually high resistance to heat and humidity. Hear them today
at your nearby Electro -Voice soundroom. Or write for details.
More U.S. recording studios use Electro -Voice microphones than any other brand.
Suggested retail price. Microphones shown
on Model 421 Desk Stand. $12.00 each.
S
ELECTRO -VOICE, INC., Dept. 422 A
602 Cecil Street, Buchanan, Michigan 49107
ICC.
In Europe: Electro -Voice, S.A., Lyss-Stresse 55,
2560 Nidau, Switzerland
a
GULTON subsidiary
Check No. 39 on Reeder Service Card
AUDIO
OUR 25th YEAR
APRIL 1972
39
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TAPE RECORDERS --
A Mew From ihe Crystal Sall
Herman Burstein
nearly 25
years that the tape recorder has
belonged to the family of home
entertainment devices, one can count
numerous and wondrous advances. The
tape machine one buys today in the
range of about $300 to $1,000 is a remarkable instrument. But is it all one
could ask for? Has the technology fully
matured? Have all the features and conveniences been thought of? From here
on can one essentially expect only more
of the same? I doubt this very much,
judging from letters to the TAPE GUIDE,
from what the experts say, from my own
experience, and from the momentum
of technology.
I have not attempted to survey manufacturers as to the innovations they
plan for the next several years. For one
thing, I suspect they are unwilling to
LOOKING BACK at the
reveal the aces up their sleeves, that is,
to tip off the competition. Mainly,'
though, I feel what the future holds is
geared to the felt needs of the present.
Therefore my thoughts about the future
do not try to conjure up undreamed of
marvels, but relate largely to problems
of the present.
Even so, some of these thoughts may
seem far out to some persons. Here I
am reminded of a conversation I had
about 10 years ago with the chief engineer for a tape manufacturer. He stated
that audio tape then was just about as
good as it ever was going to become in
terms of extended treble response, low
noise, and low distortion. Yet there
have been substantial improvements in
tape since that conversation. Hence I
hope the reader, whether amateur or
expert, will be charitable toward my
40
expectations, far out as they may seem.
For the most part my thoughts concern open -reel tape decks, which are
still the principal medium for high
fidelity. But the reader can freely translate these thoughts into terms of cassette
machines. So, following are ten possible
developments to increase the happiness
of the tape recordist.
Speed Control
A number of the better phonographs
enable the user to rapidly check and
adjust turntable speed. Strobe markings
and a neon lamp permit a check for
accurate speed. And speed may be adjusted over a useful range by such
devices as a magnetic brake or a variable -diameter shaft. Why not something
similar for tape machines? Some audiophiles with treasured tapes made on an
AUDIO
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OUR 25th YEAR
APRIL 1972
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I
.
old off-speed machine would like to
play them on a new machine if the
latter's speed could be adjusted. Individuals playing prerecorded tapes or
exchanging tapes would like to have
correct speed, or at least speed satisfactory to their ears. The meticulous
user would like to be able to check
whether speed stays correct throughout
the reel. And so on.
Reversibility
I have in mind an improvement and
extension of what is already with us.
Although a number of tape machines
feature reversibility, few do so in a way
that provides maximum usefulness.
Many of the reversible machines operate this way only in playback, not in recording. Yet to me the reversible
feature has the most importance in
recording, because the tape may run
out in the midst of a prized and unrecapturable moment of the recording
session. (I become all thumbs in trying
hastily to reverse the reels, rethread the
takeup reel, and put the tape in its
proper path. Under this kind of stress,
more than once have I put the base side
of the tape against the heads.) In playback I am less unhappy about the reel
running out, because I haven't lost any
of the material I wish to hear.
Therefore I look forward to an increased number of tape decks that are
reversible in recording as well as playback. The user should always have the
option between automatic and manual
reversal, so that the machine will not
accidentally erase the tape as the result of inadvertent reversal in recording.
Automatic reversal in recording should
be on a fail-safe basis, requiring the
user to push a button or lever each time
he wants automatic reversal. To guard
against accidental erasure, perhaps a
bell might ring and/or a light might
flash on as the machine approaches
automatic reversal.
Noise Annihilation
So quiet now are all other components of a quality audio system that
the tape deck looms prominently as the
chief offender with respect to noise.
For a long time designers of tape decks
have struggled hard to inch up the
signal-to-noise ratio by a decibel or
two. Tape companies have considered
it a prideful accomplishment to produce
a tape that-all other things remaining
the same-has 2 or 3 dB less noise. The
difference between excellent and good
S/N has generally been a mere four or
five dB or so. A high quality machine
can achieve something like 55 to 60 dB
S/N, compared with S/N or 65 dB and
higher in their components.
today's
technology
Fortunately,
points not merely to further reduction
of tape system noise by a few dB, but to
virtual annihilation of noise. Compression systems, such as those of Dolby
and Burwen, portend noise reduction
by at least 10 dB and possibly by as
much as 50 dB.
To give an idea of what this is about,
consider the tape system noise to be
at 0 dB level. Assume the dynamic
range-difference between the loudest
and softest sounds-of the program
material to be 50 dB. And assume the
S/N ratio of the tape system to be
55 dB (quite typical for high quality
home machines); that is, peak recording
level (corresponding to maximum
tolerable distortion) is 55 dB above
the noise level. If the loudest material
is recorded at peak recording level, then
the softest material is recorded 50 dB
lower, which is only 5 dB above the
noise level. Hence noise is evident on
soft passages, and even on medium
ones if volume is moderately high.
However, if S/N could be extended
to, say, 70 dB, then the softest passages
would be a handsome 20 dB above the
noise.
In view of the importance of noise
reduction, let us briefly inquire into
the basics of compression systems such
as those of Dolby or Burwen. The
Dolby, on low-level signals, supplies
boost in recording and corresponding
cut in playback. With the cut comes a
reduction of noise due to the tape and
tape deck electronics. Since this process
takes place only for low-level signalswhen noise reduction is most neededthere is no tendency to overload the
tape in recording as the result of the
boosted signal. For home machines, the
Dolby system operates only in the
treble region, where most noise lies. For
professional equipment, the Dolby system operates in several audio bands.
The Burwen system compresses all
signals, so that the dynamic range becomes, say, 10 dB instead of 50 dB.
Therefore the signal can be recorded
at a level 40 dB higher than before;
and the softest passages are an additional 40 dB above the noise of the
tape system. In playback, the signal is
expanded, so that the dynamic range of
10 dB again becomes one of 50 dB,
with the softest passages retaining
their additional margin above the noise.
(This 40 dB extra margin is only illustrative; the actual margin could be
less or more.)
Presently the tape recordist walks a
tightrope in choosing the proper recording level: too high a level, and distortion
is excessive; too low a level, and noise
is excessive. Achievement of S/N of
70 dB or higher would greatly ease his
task and would permit him to record
material with greater dynamic range.
For example, the task of recording
electric guitar, with its tremendous
peaks, would be simplified.
Instant Location
of Program Material
The index counter is a useful but
only approximate device for finding the
start of a desired selection within a reel
of tape. By comparison, it is much
easier to locate the exact start of a
section of program material (visible
band) on a phono disc, for example
the beginning of a song. Perhaps a bit
of ingenuity will eventuate in a more
precise locating device for tape.
Front -Panel Alignment Controls
The high quality tape deck incorporates a variety of alignment controls
to adjust some or all of the following:
bias level, recording level, playback
level, record -level indication, recording
equalization (treble boost), playback
equalization (bass boost), erase current,
bias frequency, etc. Generally the
manufacturer's philosophy has been to
bury these controls well inside the
chassis of the home tape machine to
prevent the unversed user from fiddling
with them. But not all users are unversed. In fact, many of those who purchase high quality machines are quite
knowledgeable or on the way to being
so. Many also possess equipment such
as signal generators, a.c. VTVMs, and
alignment tapes, permitting them to
make the necessary alignments, particularly when shifting from one kind
of tape to another. Such alignments,
or realignments, become necessary as
tape formulations change, as components in the tape deck change value
with age and heat, etc. Also, many
users like to experimentally learn the
effects of changes in bias, equalization,
etc. Perhaps we should keep in mind
that the name of the game is not only
"audio" but also "experiment." However, it is an awful pain to have to
remove 10 knobs, 24 screws, 8 grommets, an awkward electrical interlock,
and a chassis 1/16th inch wider than its
cabinet in order to get at the alignment
controls!
Some manufacturers of home tape
machines have been kinder to the user
by putting the alignment controls, or
at least the principal ones, at the rear
of the chassis. But even this can be a
pain if the tape deck must be moved
in order to get at the back. My hope is
that in the future all alignment controls
will be readily accessible to the user at
the front of the tape deck-perhaps
concealed under a hinged panel for
AUDIO
42
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OUR 25th YEAR
APRIL 1972
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Model for model, we put more into them. So you get more out
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the advanced electronics responsible for distortion -free reproduction of the widest possible range of sound. See the special
sound chambers. Even bigger -and -better baf#les for improved
sound dispersion. You won't see the quality control testing we
give every component in every speaker. But you'll hear the
super -sound results.
INSIST ON A FREE COMPARATIVE
LISTENING DEMONSTRATION
If your dealer doesn't stock Fairfax,
we'll send him a pair of speakers prepaid for evaluation...lwe pay the shipping charges both ways). If he doesn't
believe you, show him this ad.
FX-200C-Newly redesigned
with twin 8" drivers and super dome tweeter for big -speaker
sound. $99.95
FREE
COMPARATIVE TEST REPORT
Find out how experts test and rate our
speakers in comparison to other leading
speaker systems. Send for your free copy
of a highly informative Test Report.
A"must before purchase.
FAIRFAX,of course.
the jUPE &SOUND line
TAl
I
FA
X
NDUSTRTES
INC.
900 PASSAIC AVE. EAST NEWARK, N.J. 07029
Check No. 42 on Reader Service Card
www.americanradiohistory.com
AmericanRadioHistory.Com
Beware of
Stylus
carnivorous,
theVinyl
Cannibal.
Stylus Carnivorous can grow
under your phonograph cartridge,
when you haven't been careful to
check the condition of your cartridge and stylus from time to time.
He thrives on neglect. The result:
your records could suffer.
You can avoid Stylus Carnivorous
by taking your cartridge to your high
fidelity dealer for a check-up about
every six months. Our Pickering
dealers will be happy to do this for
you-free.
If your cartridge is a Pickering
(and it just might be, since more
Pickering cartridges are installed on
record players than any other cartridge) and if you need a new stylus,
you can get the precise Pickering
replacement. Ask for the one that
matches the stylus originally engineered for your equipment.
So if your stereo has been sounding strange, maybe it's not your
stereo. Maybe it's old Stylus Carnivorous. For free brochure, "Questions and Answers About Cartridges
and Styli" write Pickering & Co.,
Inc., Plainview, N.Y. 11803.
® PICKERING
for those who can Iheerl the difference"
All Pickering cartridges are designed for use
with all 2 and 4 -channel matrix derived compatible systems.
esthetic reasons and as notice they are
not operating controls.
It would be quite simple to prevent
the user from radically fouling up the
alignments if the manufacturer would
put knobs on all the alignment controls
and mark with paint the original factory
setting for each knob. Thus the user
would have benchmarks enabling him
to return to the original setting of each
control.
t,Ui;t
A quality machine already has a
signal reading device: the VU meter,
which provides readings in dB. If the
machine is further equipped with several test tones-say 400, 5,000, 10,000
and 15,000 Hz-it then incorporates
very useful built-in test equipment,
which can be used to check or adjust
bias current, equalization, recording
level, etc. In today's state of the art, a
several -tone signal generator can
probably be constructed in the form of
an integrated circuit occupying minimal
space.
How might the user put such equipment to work? For one thing, based on
the tape manufacturer's recommendation for each of his tapes at each speed,
he could adjust treble boost so that,
relative to the reference frequency of
400 Hz, it is at the appropriate level at,
say, 10,000 and 15,000 Hz. For example,
a tape manufacturer might specify that
his tape works optimally at Th ips when
recording boost is 11 dB at 10,000 Hz
and 16 dB at 15,000 Hz. Assuming the
tape machine contains suitable switching facilities so that the internal signal
generator and the VU meter are connected to the proper test points, the
user could adjust recording boost to
meet these specifications as closely as
possible.
Next he could adjust bias current so
that treble response ìn playback is as
flat as possible, as measured by the VU
meter. (We are assuming that the meter
is truly a VU meter, with essentially
flat response throughout the audio
range.) He might then make fine touchups involving both treble boost and bias
to achieve the flattest possible response.
Or, to minimize distortion, he might.
increase bias at the cost of a slight
sacrifice in treble, say 3 dB down at
15 kHz instead of perfectly flat out to
that frequency.
With alignment test tape, the user can
adjust azimuth of his tape heads;
azimuth is correct when the VU meter
gives a maximum reading in playback.
With a frequency test tape, he can use
the meter to check playback response,
and he can touch up the playback
equalization (if the machine contains
44
such provision) for flattest playback
response. By means of the internal
signal generator he can check overall
record -playback response at the available frequencies; then perhaps it might
be nice to have a few additional frequencies, such as 50, 100, and 1,000 Hz.
Using the standard reference tone on a
test tape, at which the VU meter should
read 0 VU in recording-he can adjust
the record-level indication as follows:
play the test tape; note the VU meter
reading; record the 400 Hz internal
frequency on the tape to be used for
recording; adjust recording level until
the same playback reading is obtained
as for the test tape; at this recording
level, adjust the VU meter calibration
to read 0 VU.
Peak -Reading Record-Level
Indicator
So long as the recordist is caught between the horns of excessive recording
level and excessive noise, owing to a
limited S/N ratio, it is highly desirable
to know when signal peaks are exceeding maximum permissible recording
level (corresponding to maximum
tolerable distortion). That is why I
have long favored the electronic eye,
which is a peak-reading device, over
the VU meter, which is an average reading device. And that is why it is the
practice in a number of foreign countries to use peak -reading meters.
On the other hand, a meter that reads
average signal level also has its advantages, for example in equating the
levels of different sound sources or in
making level adjustments of known
magnitude. The best answer therefore
seems to be to provide the recordist
with both average -reading and peak reading devices. For example, an
electronic eye could be built within
the case of a VU meter or it could be
mounted atop or below the meter.
Possibly a meter can be designed with
two pointers and two scales for average reading and peak -reading.
Radio -Pickup Elimination
Quite a few readers complain about
their tape machines, particularly in
playback, picking up nearby radio
broadcasts-AM, FM, military, aviation,
etc. It would be no great problem for
home tape machines to include better
filtering at the inputs of the recording
and playback amplifiers to prevent
such pickup.
Modular Components
For Easy Servicing
Audiophiles often find it quite
burdensome to go through the process
AUDIO
Check No. 44 on Reader Service Card
www.americanradiohistory.com
AmericanRadioHistory.Com
OUR 25th YEAR
APRIL 1972
© 1972 Superscope, Inc., 8142 Vineland Ave., Sun Valley, Calif. 91352
of having their tape decks serviced.
Often this involves locating a reputable
service agency, lugging or shipping the
machine to the agency, waiting several
weeks or months for the machine to be
serviced, and hoping the machine is
cured of what ailed it-a hope too often
unfulfilled. Use of modular components, perhaps some 8 or 10 modules
for the electronics, could go a long
way toward helping the user be his own
serviceman. If separate modules are
employed for each stereo channel, most
of the modules would be duplicates,
permitting interchange of modules
between channels in order to identify
a defective module. For example, if
Channel A isn't recording but Channel
B is, then substituting Channel B
modules into Channel A, one at a time,
is apt to turn up the defective module.
If modules can be kept to a low cost,
say under $10 each, it might pay for the
user to stock spare modules in the way
he used to stock spare tubes.
I wonder how far the modular approach can be carried out in the case of
the electro -mechanical portion of the
tape deck, that is, the transport
mechanism. Given hard thought to the
matter, design improvements might be
achieved which permit the user to at
least make some repairs with ease, such
as changing belts, brakes, idlers; adjusting tape tension; replacing heads;
etc. In this age when good service is
hard and costly to come by, it is to be
expected that the machine of the future
will be serviceable by the user to a
higher degree than now.
Improved Logic
Modem tape recorders pay much
attention to the logic of their controls;
that is, to be proof against the user
making the wrong move which might
break tape or accidentally erase a recording, and to minimize the number
of controls and connections required to
achieve a desired effect. It is to be
expected that the trend will continue.
To illustrate, not all tape machines
give adequate warning that the unit is
in record mode; a panel lamp that
glows when the machine is in record
mode, and starts glowing before the
transport starts up, is desirable. Not
all machines make it easy to get into
the sound-on -sound mode; some require special reconnection of cables.
Some machines facilitate feeding a
mono signal into both outputs of the
unit, while others don't. With some
decks it is easy to record on one
channel while playing the other, and
with other decks it is difficult or impossible.
AUDIO
APRIL 1972
45
"hen you make
the number one
tape recorder,
you make the
number one
recording tape.
Sony!
assette. Reel-to-reel. 8 -track.
SONY®
SUPERSCOPE
You never heard it so good.'®
Check No. 63 on Reader Service Card
11lL1If05[I CATALOG
and FM DIRECTORY
Get all the newest and latest information on the new McIntosh Solid State equipment in the McIntosh catalog. In addition you will
receive an FM station directory that covers all of North America.
MX112
FM STEREO/AM TUNER PREAMPLIFIER
-ALL SOLID STATE
McIntosh Laboratory Inc.
2 Chambers St., Dept. AE11
Binghamton, N.Y. 13903
SEND
NAME
TODAY!
ADDRESS
CITY
STATE
Check No. 45 on Reader Service Card
www.americanradiohistory.com
AmericanRadioHistory.Com
ZIP
Open Reel
Tape Recorders
Crown SX824
Akai GX-280D
Concord Mark VIII
Astrocom/Marlux 711
`
8
P
MANUFACTURER
D
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Od
6KM
X330
qv
58
Yes
A
1054
r. r.
4
4
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ó
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ó
3
ó
Hys.
Belt
30-25k
g~ S
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0.04
?r
4
50
60
10k
55
60
10k
No
G
7
3
4
3
Hys.
Belt
30-28k
0.04
+3
1730.55
B
No
7
4
4
1
Hys.
GX280D
B
No
7
3
4
3
Ind.
3022k
ALLIED
30-24k
0.12
50
75
30k
0.08
50
60
101(
60
IOk
+3
GX.2200
A
No
7
3
4
3
Ind.
Direct
3024k
0.08
50
9098
A
Yes
7
2
4
1
Ind.
Belt
50.18k
0.2
40
t3
9998
AX.300
ASTROCOM/MARLUX
711
B
4 -Chan.
F
407
B
OLUFSEN
CONCORD
No
A
Beocord
1800
A
Beocord
2400
A
MK
No
A
AMIEX
BANG AND
x 91
2
17
x
Mtrs.
x
18
2
2
A
No
7
7
101
3
6
4
4
0.2
20-20k
0.09
2
40
Mtrs.
4
3
Hys.
Idler
57
55
Hi
*3
4'
2524k
3
0.06
60
Lo
Mk 4
A
No
.
No
7
7
4
3
4
4
3
1
Hys.
Hys.
Belt
Idler
30.20k
3018k
0.07
0.07
50
65
60
120
10k
200
t2
Yes
Yes
7
7
3
2
4
4
1
Hys.
Idler
3418k
0.07
65
120
200
t2
B
8X824
B.
2
Ind.
Belt
5012k
0.2
1
Hys.
Idler
2023k
0.08
No
7
4
4
Opt.
Opt.
101
101
3
3
4
4
3
Hys.
Belt
45
2k
50k
52
E
SC744
B
2025k
0.09
60
45
350k
+2
3
Hys.
Belt
x
x
33
44
.411
14
25
X 7%
131
Mtrs.
x
x
141
2020k
2
0.09
60
45
Opt.
Opt.
101
101
3
3
2
3
Hys.
Belt
30-30k
0.06
60
45
+2
4
3
Hys.
Belt
20.25k
Under
2.000.00
0.09
60
45
21
x
x
171
2
171
x
Auto rev. PB; s-w.s;
15
36
400.00
S
15
37
450.00
As above w. 2
so -s-: solenoid coots.
-os; echo; sync. PB;
PA
facility: mixing.
83/4
x
2
Mtrs.
x 81
2
17
Mtrs.
x 81
x
17
2
19
x
Mtrs.
x
151
2
19
x
Mtrs.
x
151
9
9
250
2
19
x
(bal)
Mtrs.
x
171
350k
4
19
x
Mtrs.
x
21
9
19
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
4.chan.. synch. recording, mixing.
459.95
x 81
18 x 161
46
Speed logic cir.,; outside bias A VU mtr.
calib.; heads-2 rec., 2 PB. 2 erase.
27
141
101
x
+2
599.95
6
Mtrs.
350k
199.95
179.95
45
4
Dual
Mtr.
4`
17
x
X71
16
18
91
241
1654
+2
F
CX822
x
2
Mtrs.
t4
SX724
171
56
10
Special
Features
S
4854
1854
Mirs.
orb
CROWN
Mtrs.
Mtrs.
40-20k
141
4
Mtrs.
RADIO SHACK
x
x 91
161 x
x 111
161 x
2
,r
o`
171
2
d
c0
X034
ca
4
Mtrs.
+3
Direct
ß
Mtrs.
_+3
GX-365-D
4
m
x
,vc
IOW. ems amps.
49
319.95
251
279.95
Auto Rev. PB. silent sensing: dual capstan.
45
995.00
Dual mike -line mixing;
5 -in. VU mtrs., also 1 track.
48
1,495.00
53
2.120.00
60
1.895.00
Wal. Cab.: tape contr. opt.:
also
1 track.
As above: also 4
8
-chan. 1 trace.
mike inputs.
OUR 25th YEAR
APRIL 1972
Speeds Indicated by lottar code:
A
E
C
D
15
7½X
344x
1'%X
r.4e
X
X
X
X
X
X
at the highest
E
F
G
X
X
X
H
XXX
XX
X
X
X
speed f the
X
chine
m
Pioneer QT-6600
J V C 1694
MP ISM
It
I
Kenwood KW-8077
Revox A77 -Dolby
Á
F
ó
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a'
MANUFACTURER
,ic
Á
GRUNDIG
TN -600
IVC
1694
B
No
7
A
No
7
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,A
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c
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tº`
F°
4
I
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50
0.15
52
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30-20k
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100k
+2
3
.
2
16%
Mtrs.
x
Idler
B
No
7
3
4
I
8W40664
A
No
1
3
4
I
Hys.
Idler
KW -4077
A
No
7
3
4
1
Hys
Idler
1400
-chan.
20-25k
0.07
53
0.15
50
150
IOk
0.12
50
260
2k
10k
+1.5
4
1ENWOOD
2520k
+3
20;20k
+3
KW -6044
A
No
7
3
4
1
Idler
Hys.
0.12
50
150
50
+3
4 -chan.
KW5066
20-20k
A
No
7
4
4
B
No
7
6
4
3
PANASONIC
RS.736US
E
No
7
3
4
1
PIONEER
1-8800
B
No
7
6
4
2
Ind.
7
0.15
50
2020k
004
52
30-25k
Hys.
Belt
40-15k
T-6600
B
No
7
4
4
1
T-6100
B
No
7
4
4
1
Hys.
Belt
Hys.
Belt
50-15k
279.95
Rec. bias adjust: s -o -s
46
559.95
Auto Rev. PB 6 Rec.; search sys.;
5 -step equalizer control.
33
329.95
Bias adjust.; mixer; s -o -s; s -w -s.
50
549.95
PB/Rec auto rev.;
x
19%
150
600
20k
2
17
x 84
Mtrs.
x
184
55
110
50k
2
21-29/32
Mtrs.
x
2
17.3/16x7.5/32
Mtrs.
x
.12
55
110
50k
.12
55
110
50k
x
164
4
-
1
Hys.
Bett
30-20k
.12
55
110
50k
Hys.
Direct
35-26k
0.08
56
60
50k
477
B
Opt.
104
3
2
3
Hys.
Direct
31-20k
0.08
61
60
Hi,
2
Lo
477 HS
F
Opt.
104
3
3
Hys.
Direct
30-20k
0.04
64
60
Hi,
Lo
slide vol. controls.
G
head; bias seleo.;
28
299.95
PB/Rec. auto rev.: pause cord.; easy load.
26
249.95
PB auto rev.; pause cont.; easy load.
17
Mtrs.
3
auto stop; auto 6
manual rec. level.
s -o -s; easy load.
9%
15-15/16 x
6-27/32 x14%
2
2
-
rec/P13:2chan. rec. /PEI: auto rev
599.95
4 -chan.
69
675.00
Solid state, modular plug-in hoards.
Portable case, $37.00. 704-TRSQ has
8
34
649.00
For Dolby, add $21000.
8
34
749.00
Mtrs.
+2
2
or 4
OUR 25th YEAR
+1.5
19
x 84
x
21
16
x
Mtrs.
x
14
2
16
x
Mtrs.
X
14
2
Mtrs.
+2-3
or4
AUDIO
22
Mtrs.
3
REM01
4-chan. PB: auto stop.
2
104
4
Auto rev. 6 repeat: slide vol. cants.
359.95
x 17%
x 74
16 x 154
x7
16 x 154
x7
17 x 9
No
5
309.95
22
7
16
No
7
264
x
2
E
-6600
Auto stop; slide vol. coots.; bias sett.:
tape mont. & mode writ.
53
4 -chan.
706-TROH
4-chan. PB & rec.
199.95
Mfrs.
B
QT
PREMIER
399.95
22
x
.08
+2
50-15k
_+2
20
12%
16
0.09
+2
(4)
84
12%
x
x
2
+3
Hys.
S-o -s, s -w -s,
144
12%
15%
Mfrs.
25-20k
S-o -s,
149.95
2
Mfrs.
NW -8077
430.00
20
Mtrs.
4
Special
Features
8%
x
4
Mtrs.
.
714
154
x
x
is
4
tracks.
Auto rewind: varia. pitch.
As above.
47
APRIL 1972
www.americanradiohistory.com
AmericanRadioHistory.Com
Open Reel
Tape Recorders
Sony/Superscope TC -277-4
Sansui SD7000
Tandberg Series 6000X
.-r
ÿ'\
MANUFACTURER
°`ÿ
SHNSU1
SD7000
SONY/SUPERSCOPE
252-D
B
No
A
No
7
7
353-D
A
330
A'
Yes
7'
440
A
No
7
No
7
4
2
3
é
4
4
4
e
&
3
I
1
Hys.
Belt
Ind.
Idler
Ind.
Idler
e
'ti
F
f
15.25k
0.06
m
60
..
100
3025k
012
0.12
52
55
150
150.
600
Lo
+3
4'
4
30-25k
1
580
A
Yes
7
4
4
3
640
B
No
7
3
4
3
6502
B
No
7
3
4
3
0.06
56
100:
Lo
3025k
Hys.
Idler
3020k
0.06
56
60
Lo
0.07
55
90
Lo
30.22h
Hys.
0.04
59
90
Lo
0.09
56
180
Lo
+2
770-2
A
No
E
No
7
7
10
2
16.1/16x15
Mtrs
x
2
17
679.95
18
159.95
252, with amps, $229.95.
18
219.95
353, with amps, $329.95
349.95
'Reeito-reel plus cassette.
27
369.95
'Auto reverse,
6
43
499.95
'Auto reverse.
6 head
33
349.95
Timer activated rec, PB, & stop.
1014
x 71
13-7/16
15%
x
4
2/4
3
2
4
2
20-22k
1
16-9/16x8%
Mtrs.
x
2
17.9/16x8'.
1
20-22k
0.09
58
3
30-25k
003
57
250
x
-head function.
16-3/16
function.
181
Mtrs.
141 x 91
x 151
2
16%
Mtrs.
x
2
Auto rev. w. 20 -Hz sig. rec. burilin, auto rewind:
60
opt. rem coot, auto sleep sw.
2
Mtrs.
+3
No
x
x
Mtrs.
+3
A
21
Mtrs.
Special
Features
-
erp
Lo
+3
1704
Fp
F' +
<e.
2
2
30.18k
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g`
¿
,
vD
s 'y
@
BP
e
.y
x
46
499.75
650-4 1475.00.
25
795.00
With
Mtrs.
161 x 513/16
x 15-5/16
2
16%x15-15/16
25
795.00
57
895.00
850-4, quarter track, $895.00
21
499.95
4
-chan. rec & PB.
481
875.00
4
-chan. rec. d PB.
2
954
17-5/16
2 ECM -22
mikes, n4cad battery.
Mfrs.
850-2
101
65
Lo
2
Mtrs.
Ind.
Belt
20-25h
009
55
120
Lo
Hys.
Direct
30-22k
0.04
57
60
Lo
B
No
7
4
4
1
654-4
4 -chap.
B
No
7
4
4
3
854-4S
E
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4020k
40.20k
x
x
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17
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x
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x
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x
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4chan.
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349.00
30418, 1 track, $369.00.
12%
23
459.00
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4041 XQ,
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AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
402 chap.
pause cont., auto oft.
x
x 61
151 x
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2
'Bal. Cannon
rec & PB, sync s -w
22
4
Mtrs.
60
+2
40418
171
21
499.80
$478.50:
PB, $559.50.
4 -chap.
60210. 1 track, $528.00.
OUR 25th YEAR
APRIL 1972
Telex 2001
Speeds Indicated by letter code:
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3M/Wollensak 6364
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50-15k
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50-15k
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100
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100
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30-20k
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40-I8k
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35-20k
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A
Yes
A
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7
3
4
2
Hys.
'Idler
3620k
3
4
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Hys.
Idler
35-20k
OUR 25th YEAR
1
±2
Pause; bias swit.; ad¡. turntable height.
37
729.00
Sync. overdub; 462 (%) than.
Rec. 6 PB; 1/2 track PB.
1744
37
365.00
Compatible 4- and 2 -chan stereo p.b. deck; 4 p.b. ampio;
auto reverse for 2 -than. operation.
1754
37
535.00
+than
37
695.00
4
4
1744x7
x
12
12
x
7
x
2
12
Mtrs.
X
7
12
x
Mtrs.
X
7
0.12
50
deck
1744
deck
41
329.50
S -o -s;
x
8
3744
499.50
Pause cont.; bias switch
9%
48
549.50
S-o
6%
52
799.50
Auto rev., rewind. stop: mixing.
62
999.50
As above.
8%
34
394.95
Walnut base.
1644x6%
30
249.95
26 /chan.
x
50
90
10k
Dual
Mtr.
171/4
90
600
2
1744
Mtrs.
X 11%
2
1744
Mfrs.
x
2
1754
Mfrs.
x
2
15%
Mfrs
x
58
90
600
58
90
600
0.2
54
0.2
50
70
50k
x
echo; opt. rem. pause tont.
17
55
0.06
-chan rec. and p.b. deck; compatible with 2 -chan.
%.track stereo rec. and p.b. Amp. as above.
9%
1744
0.08
0.06
p.b. and 2 -chan rec. and p.b. inch. connectors
to adapt to 4th'an. recording. Amp 4% x 171/4 x 7%in
X
Dual
Mtr.
008
14%
x
x
-s; echo; opt. remote tont.; auto off;
tape tension switch; bias switch.
20%
x
81/4
20%
X
14%
PB
only.
x11
0.18
52
0.12
54
Hi
90
2.2
0.12
54
90
2.2
012
54
90
2.2
+2
-chan.
6364
4 -chan.
Bias swit.; pause; also available
in several track/speed configurations.
399.50
X 8
15
4
±2
6154
549.50
3744
944
x
±3
A
4054
x
Mfrs.
10k
±2
3M 'WOLLENSAA
Bias swit.; 2 direc. rec 6 PB;
auto rev. cont. PB; pause d lade.
15%
10k
±3
A
Bias swit.; meter sensitivity switch.
699.50
17%
100
10k
Features
949.50
x
100
100
3
Qa,
4044
2
50
+3
A
154E
.
o,
62
934
Mtrs.
50
±3
spd.
7010SL
Quad/Sonic
17%
012
+3
spd.
601051
433
x
X
±3
TELEX
x
10k
±3
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B
2
20%
18
0.12
±3
4010SL
x
2
Mtrs.
+3
spd.
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1744x8%
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+3
spd.
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Mtrs.
APRIL 1972
799.95
Monitor; solenoid operations:walnut base.
131/4
18
199.95
Bias selector: tape -source monitoring.
131/4
18
319.95
4 -chan. pre -amp playback; 2 -chan. record -play deck.
399.95
Amplified 4 -chan. play;
8
x
644
2044
X
X
644
16%
x
x
1444
x
1144
30
2 -chan.
record and play.
71/2
49
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Equipment Profiles
TEAC A-24 Stereo Cassette Deck
Marantz Imperial 6 Speaker System
50
52
Telex 48H 8 -Track Cartridge Player
54
this key is depressed simultaneously with the PLAY key; both
remain down and the recording function is indicated by an
illuminated jewel just above the RECORD key. The next key is
labeled STOP AND CASSETTE. If the machine is winding tape,
either in the play or record modes or in either of the fast
directions, the tape motion simply stops. If the tape is stopped,
the door of the cassette compartment snaps open and the
cassette is pushed forward enough to he easily picked up
with the fingers. When the door is opened, a cassette may be
inserted in the plastic track on the underside of the door and
pressed until it clicks. Closing the door engages the hubs of
the cassette with the reel spindles. The next key is the REWIND
control. When this button is depressed the tape is rewound to
the left spool; when completely wound, the drive shuts off
automatically. The next key is for FAST -FORWARD motion,
but it does not stay down-it must be held with the finger as
long as the tape is being moved forward. The two fast-wind
keys are indicated by arrows pointing in the direction of tape
TEAC Stereo Cassette Deck Model A-24
MANUFACTURER'S SPECIFICATIONS
Track System: 4-track, 2 -channel, stereophonic system.
Compatible Tape: C-60, C-90 Philips -type cassette tapes.
Tape Speed: 1'/s ips. Wow -Flutter: 0.2%. Fast -Forward
Time: Approx. 70 seconds with C-60 tape. Signal -To -Noise
Ratio: More than 45 dB. Frequency Response: 40 to 12,000
Hz. Inputs: Microphone, 0.3 mV (-70 dB) at 600 ohms; Line
and Tuner, 0.1 V at 50,000 ohms. Outputs: Line, 0.3 V at
10,000 ohms load; Headphone, 8 ohms. Power Requirements: 117 V a.c., 60 Hz. Power Consumption: 20 W
maximum. Dimensions: 135/e in. W, 9% in. D, 41/4 in. H.
Weight: 11 lbs. net. Price: $ 179.50.
The increasing popularity of cassette tape practically demands that some model of cassette recorder he included in
any modern hi-fi installation. And there is an enormous
selection of them available today -45 of them in the highfidelity category were listed in the September Buyers' Guide
issue, and there are many more than that on the market,
although not all by any means could be called hi-fi, even
though they are so labeled.
Improvements in tape formulations, increased bias curent, Dolby systems, and reduction of wow and flutter as
a result of more -precise manufacturing, and the use of
hysteresis motors have all contributed to the better performance obtainable from cassette recorders and players on the
market today. The A-24 employs most of these features.
In addition to having the usual compartment for the cassette,
there are six "piano -key" controls which effectuate all tape motion functions. At the left is the red RECORD key. To record,
motion.
The next key is the PLAY control. When it is depressed, the
tape proceeds at its leisurely I 78-ips speed under control of the
capstan and pinch roller. The last key, marked PAUSE, lifts the
pinch roller slightly so the tape does not move. This is convenient when starting to record, since with the machine in
the record mode levels can be set without actually recording
the tests which almost always precede a recording session.
Furthermore, it permits the user to make those occasional
pauses in a performance-station breaks, and so on-that if
recorded would mar an otherwise unblemished recording.
One of the protective features of the A-24-although no harm
would likely result-is that the PLAY key cannot be depressed
unless the cassette holder is closed. How to record on a cassette
which has the protective tab broken off will be described
later-though perhaps you shouldn't know it if you have a lot
of recorded cassettes.
Further to the right is the dual record -level meter, which
indicates the signal during recording to aid in getting the right
level on the tape, and it also indicates the output level while
playing back-always a useful feature.
On the flat top surface of the recorder is a panel with three
sets of controls. At the rear is a four -position switch which
selects inputs from the LINE input jacks or from the TUNER
input jacks, or from two of the five terminals on a DIN socket
on the rear apron, or, in the same position, from microphones
which plug into miniature phone jacks on the lower front of
the cabinet, just under the record -level meters. When microphones are plugged in, the DIN -plug input is disconnected.
The fourth position of the switch is for playback.
Forward of the switch is next a dual -concentric record -level
control, and forward of it another dual control for playback
level, or actually for the level at the LINE output jacks and the
AUDIO
50
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OUR 25th YEAR
APRIL 1972
stereo headphone jack adjacent to the microphone jacks, because a signal is present at these points during recording-the
source, naturally.
Circuit Description
The amplifier circuitry in each channel consists of a single
transistor input stage operating at increased gain for playback,
and at somewhat reduced gain for recording. It is followed by
the record level control which is simply the variable shunt
resistor of a "T" attenuator network. This stage, with its
switched record -level control, next drives a feedback pair,
with different equalizations being selected by the switch to
suit the requirements of recording and playback. The playback
level control follows, and its output feeds the output jacks as
well as a transistor stage which drives the level -indicating
meter. One additional stage driven in parallel with the playback level control serves as the record head driver, which has
additional equalization in its emitter circuit and a bias trap
in the output. The output line also feeds a single -transistor
amplifier stage which is transformer coupled to the 8 -ohm
headphone jacks.
A single transistor serves as the bias oscillator, with erase
signal fed from the secondary of the oscillator transformer,
and the bias signals fed through adjustable capacitors to the
two record heads. The split -primary power transformer (for
operation on either 117 or 240 volts) has two secondariesone to drive the single hysteresis motor (at about 50 volts)
and to feed a full -wave rectifier system to provide the 28 volts
d.c. for the amplifier section, and a 5 -volt winding for the
meter -illuminating lamps (which indicate POWER oN) and the
record indicator lamp.
The automatic -stop circuit is intriguing. Whenever the unit
is in any of the tape -moving modes, a relay is energized and
its contacts, which are in series with the shutoff solenoid, are
open. The relay is energized by the collector current through
two transistors in series to ground. The bases of the transistors
are connected together through a time -constant network by
a reed switch which is alternately opened and closed by a
magnet in a rubber idler wheel which is rotated by the takeup spindle. When the spindle stops (or when power is shut off)
the reed switch becomes stationary-either open or closed.
When the time constant between the bases expires, one of the
transistors shuts off, releasing the relay, and its non -operate
contacts close, causing the solenoid to operate to shut off the
unit, which it does by releasing any of the keys which were
depressed. All of this takes place fast enough so the d.c. stored
in the filter capacitors is still sufficient to actuate the solenoid.
Some similar circuitry is commonly used in the better cassette
machines, but this is the first one using this particular type of
releasing mechanism-most we have observed simply cut off
the a.c. power to the motor. In all, there are 15 transistors
and five diodes in the electronic portion of the A-24.
volts at the 8 -ohm headphone outputs. Signal-to-noise ratio
was a comfortable 47 dB, and due to the good track spacing,
stereo separation was 32 dB-about normal for cassette tapes.
Crosstalk between tracks recorded in the forward direction
and playback from tapes played in the reverse direction was
43 dB. Both rewind and fast -forward times for a C-60 cassette
were measured at 65 seconds. Bias oscillator frequency was
85 kHz, which is comparatively high for cassette decks.
A removable cover plate on the right end of the chassis
gives access to the main printed -circuit board for adjustment
Rec. /Play Head
Rec Ind. Light
Fig.
1-View
AUDIO
OUR 25th YEAR
Erase Head
of the cassette compartment showing the posi-
tions of the two heads, the capstan, and the record indicator
light.
Headphone Amp.
Performance
Frequency response-one of the most looked -for parameters
in any tape recording equipment-is shown in Fig. 3. Still more
important, perhaps, is the percentage of wow and flutter,
which measured at 0.09 per cent in the range from 0.5 to 6
Hz, 0.11 from 6 to 250 Hz, and 0.16 per cent over the whole
band. Distortion at "0" recording level measured 1.2 per cent,
while the 3 per cent point was reached at an indicated recording level of +4 dB. The input signal required for "0" level
was 84 mV from the line and tuner inputs, as well as from
the DIN socket. From the microphone jacks, an input of 0.35
mV was sufficient to provide the same recording level, all
with the record -level controls at maximum. The same recorded
signal from the tape provided a line output of 0.7 volts with
the playback level control at maximum, and an output of 0.21
Capstan
Power Supply
Auto Shutoff Circuitry
Reed Switch
Shutoff Solenoid
Fig. 2-The underside of the chassis showing locations of the
main circuit boards and the reed switch, which actuates the
shutoff mechanism.
APRIL 1972
51
www.americanradiohistory.com
AmericanRadioHistory.Com
of bias level. A 0.5 -amp. fuse protects the unit against failure
of any power supply components. Both the motor rotor and
the flywheel are dynamically balanced. Not mentioned in the
instruction booklet is the fact that both motor and flywheel
-
40
100
400
IK
FREQUENCY
4K
IOK
20K
-Hz
Fig. 3-Frequency response for a signal recorded and played
back. Recording input level was 15 dB below indicated "0"
level. Tape used was a TDK C-60SD cassette.
which is on the capstan shaft-have two grooves on their
pulleys so the machine could be converted to 50 -Hz operation
in minutes.
The construction of the A-24 is apparently meticulous
throughout. In many recorders and decks, we have noticed
that the meters were held against the front panel by foam pads
without any other fastening to keep them in place, so they
depended solely on the pressure of the cover panel to locate
them accurately. In this machine, however, while a foam pad
was used to mount the meter, the two were cemented together
and to the chassis so the meter remained in the correct
position even when the housing was removed.
The TEAC A-24 cassette deck is easy to handle, effective in
its performance, and an overall delight. It should do a lot
toward carving a niche in the home music system for cassette
machines. The instruction book accompanying the unit is complete and should serve as a good introduction to tape recording for the complete novice. For instance, the instructions
tell how you can defeat the anti -erase feature common -to all
cassette machines-the protection offered to a cassette when
the safety tab in the back of the cassette is broken outyou simply depress the RECORD key before inserting the cassette. One other provision in the instruction book is the
inclusion of a schematic. While it is not expected that the
owner will ever service his machine, it is possible that some
technician might have occasion to do so and the presence of
C.G.McProud
the schematic could be a great help.
Check No. 52 on Reader Service Card
Nominal Impedance: 8 ohms. Dimensions: 141/2 H by
25Y2 W by 111/2 D. Price: S129.00.
The Marantz Imperial 6 is a new two-way system using a
10 in. bass unit with a 2 in. cone tweeter. This latter is fitted with a hard dome at the center to smooth the response
and obtain a wide dispersion. A heavy paper cone is used in
the bass speaker, and the surround is a plasticized cloth. The
voice coil is unusually large at 2 in., and the magnet structure weighs 2 lbs. Crossover is about 3000 Hz (an octave
above the tweeter resonance point), and a three -position
A
V
B/
in
Á
1000
100
Marantz Imperial 6
FREQUENCY
MANUFACTURER'S SPECIFICATIONS
System Type: Two way. Components: 10 in. bass speaker,
2 in. treble. Frequency Response: 40 to 18,000 ±5 dB.
10K
-Hz
Fig. 1-Response curves with one-third octave pink noise;
A is taken on -axis, B at 45 degrees off-axis, and C is an
average of five angles.
52
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
OUR 25th YEAR
APRIL 1972
switch gives a choice of lift or cut. Instead of the usual acoustic suspension or infinite baffle arrangement, the 6 uses a
tuned port and the enclosure itself is filled with fiberglass.
The cabinet is finished in walnut with a black trim and
appears to be solidly constructed. The grille cloth is brown
and the front is held on by plastic foam pads.
Figure shows the response curves using one-third octave
pink noise; A is taken on -axis, B at 45 degrees, and C is an
average of the response at five angles. All were measured
with the treble control in the center or normal position. Re1
Brod &
Kpr
25
50
I
u
I
13,11.1
sponse below 200 Hz will be affected by room conditions,
and a corner position will, of course, increase the low frequency output. The small dip at 200 Hz is due to phase cancellation and should be disregarded. Figure 2 shows the
frequency response with the treble switch in its three positions and it will be seen that each step has a one dB change.
At 7 watts input, frequency doubling commenced at 42 Hz
but a useful output was obtained down to 35 Hz. Figure 3
shows the harmonic distortion at 5 and 10 watt levels.
Transient response was particularly good at low frequencies,
8 Klee,
B4Od 8 Klmr
7
1
db db
40 20
30
15
20
10
10
5
o
o
91111111.11r."."1"
50
20
10
100
200
500
2000
1000
5000
10000
20000
c/e 10000 A
(1811/2111) A
B
B
C
C
114
1
Fig. 2-Frequency response with the tweeter level control in three positions.
as can be seen from the tone -burst photographs in Fig. 4.
The impedance curve showed a low point of 4.5 ohms, rising to a maximum of 22.5-typical of two-way systems. System resonance was approximately 60 Hz. White noise tests
5W POWER LEVEL
IOW POWER LEVEL
ire....
ó
confirmed the smooth overall response and coloration was
quite small. Sensitivity was somewhat above average; quoted
efficiency is 95 dB SPL from one watt input at 400 Hz. An
amplifier with 15 to 25 watt rms per channel capacity would
be sufficient for most people when used with Imperial 6
speakers in a medium-sized room.
3
IL_-
20
100
1000
FREQUENCY-Hz
Fig.
3-Harmonic distortion
at low frequencies
Listening Tests
The first impression was of a better-than -average transient response and a clean bass with a commendable freedom
from coloration-especially in the 80 to 200 Hz region, which
can give that voice -in -a -barrel effect. Extended listening tests
over a period of three weeks confirmed these opinions. The
center or normal position of the treble control was found to
be the best for my room unless the speakers were angled
inwards when the highest position was preferred.
Summing up: The Marantz 6 can be recommended to those
who require a bookshelf system with above average performance.
T.A.
A
B
C
D
Check No. 53 on Reader Service Card
20
Fig. 4-Tone-burst response at A, 50, B, 100 C, 3000, and
D,
10,000
AUDIO
Fig.
Hz.
OUR 25th YEAR
APRIL
100
5-Impedance
1972
1000
FREQUENCY-Hz
10K
characteristics.
53
www.americanradiohistory.com
AmericanRadioHistory.Com
and the fourth. The third mode is the AUTOMATIC 4 -PROGRAM
and all bands on all tapes are played in order. The last choice
is called REPEAT and it enables all four programs of a particular cartridge to be played again. These four press -buttons
can be seen in Fig. 1. On the right is an illuminated push-bar
switch which functiolis as a reject control as well as giving
visual indication so that one can see what band is being played
at a particular time. The top button operates the AUX selector
switch for inputs from a tuner, record player, etc. At the bottom
is the cartridge selector switch labelled 1 to 12 and below that
is the oN/oFF switch. At the top of the panel are the volume,
balance, and tone controls with the cartridge load switch in
the middle. At the rear, shown in Fig. 2, are the AUX input
sockets, preamp output, and speaker sockets. Thus, the unit
Can be connected directly to a hi-fi system if so desired.
Much thought has obviously been given to the mechanical"
details; for instance, depression of the AUX switch when a tape
is playing not only connects an external input, but the tape
cartridge is automatically returned to its stored position. The
motor and its fan are left running to give ventilation. A single
shaded-pole motor is belt -coupled to the capstan and flywheel
assembly for tape drive and operation of the changer mechanism. See Fig. 3. Under the motor, to the left, is the track shifting solenoid which is energized by a power transistor in
Telex 48H Automatic 8 -track Tape Player
MANUFACTURER'S SPECIFICATIONS
Magazine Capacity 12 Cartridges. Power Output: 15 watts
peak. Distortion: Less than 2%. Speaker Impedance: 3 to 8
ohms. Frequency Response: 50 to 5,000 Hz. Preamp Output: 1 volt p -p. Signal/Noise: 40 dB unweighted. Wow and
Flutter: Less than 0.30% rms. Dimensions: 9 in. H. by 18 in.
W. by 26 in. D. Price: $299.95. Loudspeakers, Model P2/H:
1
$69.95 pair.
The Telex 48H, formerly distributed by Quatron, uses a
novel rotary magazine for 8 -track tapes, allowing up to 13
hours playing time. Any standard 8 -track tape of any length
can be used and there is a choice of four operating modes. The
first permits the selection of any program on any tape, the
second-called INTERMIX-plays the first program on Tape 1,
then the first on Tape 2, and so on, right up to number 12.
then follows the second program on each tape, then the third,
Fig.
3-Inside view.
2.0
Fig.
1-Control panel.
T
Z
tt
1.0
o
I1d
r
t7
o
2
6
4
OUTPUT
Fig.
2-Rear
panel.
Fig.
4-Power Output,
54
6
WATTS
both channels driven (4 ohms).
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rN 0
OUR 25th YEAR
APRIL 1972
a trigger circuit operated by sensing foil on the tape. Above
the motor, to the right, is the capstan shift solenoid which
either engages with the capstan drive to change a cartridge
or with a cartridge pinch roller for playback. This solenoid is
operated by a complex transistor circuit employing a multi vibrator arrangement. A starwheel (not shown) projects below
the cabinet and rotation gives a small amount of vertical head
adjustment to take care of alignment errors on certain com-
For What's New and
Best in Paperbacks...
mercial tapes. If crosstalk is experienced, the wheel is turned
accordingly.
a00US:
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Ili
Circuit Details
excerkls.
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tovewumdk
The preamplifier uses three transistors in each channeltwo amplifiers and an emitter -follower output. The AUX input
is taken to this point which is followed by a passive tone control and the volume control. The preamp output is connected
here and then comes the main amplifier which uses a NPN-PNP
pair driving a complementary pair output stage. A single d.c.
supply is employed so the speakers are capacity coupled.
Performance
Figure 4 shows the power output with THD and IM distortion. It will be seen that total power measured just over 8
watts per channel. Overall frequency response of the amplifier
from the AUX input extended up to 100 kHz (see Fig. 5), falling slightly from 30 Hz at the low end. The tone control is a
single unit and this had the effect of reducing the overall level,
giving a rise at low frequencies centered on 150 Hz. The volume control is connected as a tapped loudness control and the
frequency compensation roughly follows the tone control curve.
Figure 6 shows the response using an Audiotex test tape taken
with the volume and tone controls in the maximum positions.
Output from the preamp was about 350 millivolts. Wow and
flutter varied from 0.25 to 0.35 per cent which must be considered good for an 8 -track machine.
On test, the 48H did everything claimed for it. The mechanism worked smoothly with no problems whatsoever. The
amplifier side cannot be considered top hi-fi quality and eight
watts per channel is not a great deal of power-but for all that,
the 48H sounded surprisingly good when coupled up to a pair
of Dyna A-25 speaker systems. Using the preamp only, results
will probably be as good as the cartridge itself and a model is
available without the power amplifier at $249.95 (Model 48D).
Summing up: The Telex 48H can be recommended to those
who require quick selection of a number of tapes or continuous
programs lasting several hours for background music or whatever.
Check No. 55 on Reader Service Card
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SallEs Magic Flute
Richard Freed
A WORK
so well -beloved,
Mozart's fairy-tale opera The
Magic Flute (Die Zauberflöte)
has had relatively few recordings since
the first one, conducted by Sir Thomas
Beecham, appeared on 78s in the late
30's. The newest one, conducted by
Georg Solti on London (OSA -1397,
$17.94), brings to a total of four the
complete versions currently available
in stereo, the others being Böhm's on
Deutsche Grammophon, his earlier
one on Richmond, and Klemperer's
on Angel. The old Beecham may be
had now (in mono, of course) in an
inexpensive Turnabout set, and, unless
I'm mistaken, there have been only two
other complete Magic Flutes on records,
one under Karajan on Columbia some
20 years ago and one under the late
Ferenc Fricsay, a DGG recording
issued in mono on the Decca label, in
stereo on Heliodor, and not available in
either form at present. There are
threads of continuity running through
these seven recordings, more striking
than anything similar encountered
under any other title, and I think they
are worth noting before we proceed
to a consideration of the latest addition
to the list.
Böhm, as already noted, conducts
two of the current recordings, and the
orchestras involved in them are also
heard in others: the Berlin Philharmonic, in his DGG set, also plays for
Beecham, and the Vienna Philharmonic,
on Richmond, also figures in the Solti
version, as it did earlier in the Karajan.
More significantly, one finds several
of the singers turning up repeatedly
from one recording to the next, and
not in every case repeating their
respective roles. Fisher-Dieskau, the
Papageno under both Fricsay and
Böhm on DGG, is the Speaker in the
new Solti version; Martti Talvela, one
of the Armed men in Böhm/DGG, is
Solti's Sarastro; Franz Crass, the
Böhm/DGG Sarastro, is the Speaker
and an Armed Man under Klemperer;
Martin Vantin, Fricsay's Monostatos,
is the Priest in Böhm/DGG; Walter
Berry and Christa Ludwig sing the
FOR
same roles-Papageno and the Second
Lady, respectively-on Angel and
Richmond; Emmy Loose and Wilma
Lipp, the Papagena and Queen of the
Night on Richmond, also sang those
roles under Karajan on Columbia.
There may even be more such phenomena to be catalogued. The point
of it all is that the performers involved
in these recordings really are "involved"; many of them have lived with
this material for some time, so that
there is a cohesiveness and commitment
evident in every one of these sets, such
as one simply cannot expect when a recording is undertaken by musicians who
have had little or no experience in
their respective parts.
And, happily enough, all of these
sets are so fine that one may find oneself quibbling over degrees of excelllence. But there are varying degrees,
to be sure, and there are some disappointments here and there. Because the
new Solti set offers the fewest disappointments and the greatest number
of outstanding successes, I have little
hesitation in placing it at the top of
the current list.
The Beecham mono version's appeal
must be on historical and/or sentimental grounds, so we can discount it
as a serious contender against the
four stereo versions. Of those, I would
eliminate the Klemperer/Angel because,
compared with the others, it lacks
warmth and the air of fantasy I consider
so indispensable to this music. Dignity
it has in abundance, and, of course,
gorgeous singing and playing, but it's
really a little stuffy if measured against
the Gemütlichkeit of the two Böhm
versions and the sparkle of the new
Solti.
And Solti's does sparkle, for sure.
He is one of the really supreme opera
conductors of our time; since Böhm
is one of the few others, lovers of The
Magic Flute have a rather dizzying
assortment of riches in the three sets
under their direction. If Solti's pacing
is a bit brisker than Böhm's, that is
not to say that Böhm is at all sluggish,
or that Solti is headlong; in fact, their
56
approaches are not significantly dissimilar. Since both have first-rate
orchestras and, in the two newest sets,
on DGG and London, superb recorded
sound, the choice may be based almost
entirely on the vocal contributions. If
economics should be a factor, though,
the earlier Böhm version, on Richmond,
is very much worth considering, for
the interpretation is the same as in his
DGG remake, and some of the individual roles are even stronger: Walter
Berry, for example, is a much more
satisfying Papageno than FischerDieskau, and Emmy Loose is the ideal
Papagena. The main weakness of the
Richmond set is its Sarastro. True
enough, Sarastro has only two big arias,
but so, for that matter, does the Queen
of the Night, and much of the work's
overall impact rests on their effectiveness. Kurt Boehm, though he made a
valiant effort, simply was not in the
same league as Talvela, Crass, Gottlob
Frick (with Klemperer) or Ludwig
Weber (Karajan).
Taking the principal characters role
by role, they are pretty evenly matched
in the Böhm/DGG and Solti/London
recordings, but the latter has a more
impressive Queen of the Night in
Cristina Deutekom and a much more
appealing Papageno in Hermann Prey.
Fischer-Dieskau's Papageno was just
too cutesy and heavy-handed for my
taste, enough to mitigate my enjoyment
of the otherwise excellent Böhm set.
Prey is surely today's outstanding
Papageno (the real successor to Erich
Kunz), and it was high time he recorded
the role. Deutekom, whose only previous recording seems to be her recent
recital disc for Philips, is both a secure
and a daring singer, turning challenges
into opportunities for really dazzling
display. Roberta Peters, on DGG, is no
slouch, either, but Deutekom is simply
a knockout.
If Prey's Papageno is "definitive"
now, the same might have been said of
the late Fritz Wunderlich's performance
as Tamino, which is one of the strong
points of the DGG set. Stuart Burrows,
however, proves to have been an
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OUR 25th YEAR
APRIL 1972
inspired choice with Solti: he does
honor to the great line of recorded
Taminos which includes Anton Dermota
in the old Karajan set, the great Mozart
stylist Léopold Simoneau on Richmond,
Ernst Haefliger with Fricsay, and
Wunderlich himself.
Solti's Pamina is Pilar Lorengar,
who has shown unsteadiness at times
but here, as in her recent Traviata under
Maazel and in the Egmont music with
Szell, gives one of her finest, most
persuasive performances. Martti Talvela,
as one might have predicted, brings to
his role all the majesty, all the dignity,
and at the same time all the warmth
and compassion one wants in a really
convincing Sarastro, and Renate Holm
makes a most attractive Papagena.
Aside from thefactor of exceptionally
fine singing, there is the utterly convincing characterization on everyone's
part. The recording, by the way, does
include the spoken dialogue (as do all
the others now except the Klemperer),
and this, too, is handled most effectively, with a bit more charm than on
DGG. One other especially charming
touch, which had not been attempted
on records before, is having the Three
Boys actually sung by boys instead of
women. Solti's Boys are three members
of the Vienna Boys' Choir, and they
are most effective, without in any way
compromising the extraordinary musical
standards of the set.
Sometimes when one is carried away
with enthusiasm it becomes difficult to
tabulate the reasons for it dispassionately, and perhaps I have not done
as much of that as I might have done
in this case, but I hope I have made it
clear that I think the Solti Magic Flute
is the outstanding recording of this
work so far, in every respect. As in
many of London's other operatic recordings, there are some sound effects
to help make the drama `visible through
the ear." We hear the padlock click
when the Ladies affix it to Papageno's
mouth, and when the Queen of the
Night appears there is thunder beyond
what is produced by the timpani.
I don't find these things at all disturbing. Indeed, the only disappointment
I can report, after hearing the set
through three times over, is Solti's
use of the celesta instead of a glockenspiel when Papageno plays his bells.
Böhm does use a glockenspiel on DGG,
and the effect is enchanting.
By way of documentation, the booklet
with the new London set includes an
interesting essay on the opera's Masonic
significance, on Freemasonry in Vienna,
and on Mozart's involvement with it,
by Arthur Hutchings.
/E
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Edward Tatnall Canby
The Three Tchaikovsky Piano Concertos. Gary Graffman; Philadelphia
Orch., Ormandy; Cleveland Orch.,
Szell. Columbia MG 30838 (two
discs), stereo, $6.98.
As you peruse this brand-new Columbia album, you will note that the
Cleveland Orchestra now belongs to
Angel and the Philadelphia to RCA and
Mr. Szell has been dead quite a time.
So it goes. But the idea of putting the
"21/2" concertos together in a special
album is a good one, basically. (The
"half" concerto is the one completed
movement of No.3, not widely known
mainly because it leaves the soloist
high and dry in midstream.)
Gary Graffman is a powerhouse
pianist, the sort who can make a huge
piano sound even larger than life, and
a big piece sound even bigger. He has
the necessary dramatic flair. But he
is a pounder if ever there was one. He
has good musical instincts but at the
drop of a conductor's baton they turn
to muscularity. A good conductor, who
wants to, can work wonders with such
a pianist. An easy-going conductor just
lets him pound.
That, it seems, is what the ever-amiable Mr. Ormandy did. Ormandy is a
marvelous accompanist-that is, he can
bend his orchestra to follow a solo
musician the way a lied accompanist
must follow his singer. That isn't what
Gary G. needs! He needs a Szell. A
conductor who is a perfectionist with
his own vehicle and who demands,
directly or more likely by sheer example, the same finesse from his featured artist. In the famed Concerto No.1,
Gary pounds out those first big chords
triumphantly, but by the time the orchestra has got down to its beautifully
controlled low volume follow-up, you
are aware that there is to be more than
pounding in this version, warhorse or
no. It is a pleasure to sense Mr. Szell's
58
workmanship as the music goes onward.
Very good for Gary Graffman.
In the Second, and the truncated
Third, Mr. Ormandy goes heartily along
with Graffman, pound for pound, the
tactful accompanist at his most ingratiating! It is a royal pound -fest throughout, a rather glorious noise, it must be
admitted, but in a different league from
the carefully disciplined music under
Mr. Szell. Maybe it's worth acquiring
this whole set just so you can savor the
differences. Nice.
Performances: B,
B-
Sound: B, B+
Mass
Bernstein: Mass. A Theatre Piece for
Dancers.
Players and
Norman Scribner Choir, Berkshire
Instruments
Boy
Choir,
Soloists,
conducted by the composer. Columbia
M2 31008, two discs, stereo, $11.98.
Singers,
Rave reviews from the music critics,
the dance critics, the architects, the
sociologists, the haute monde and everybody else who got a chance to slide
into Kennedy Center on Opening Night.
A multi -media spectacle, with top
dancers, lighting, singing, chanting,
what have you, including music from
tape (a must these days) as well as live.
So what's in it for you, blind in your
living room in front of the stereo?
(Well, not quite blind-there's a superb
big book with texts and big blue -purple
blurry photos.)
It's a Mass, out of the Catholic
tradition all right, including familiar
Latin terminologies and those not-so familiar, too, like trope, a sort of insert
interlude of side -commentary between
sections. But, of course, it's Bernstein,
and it includes some Hebrew, here and
there, plus-what else?-musical comedy
à la West Side Story. But definitely!
A li'l bit of everything and no wonder
AUDIO
OUR 25th YEAR
APRIL 1972
Straight talk about a ftylur
Listen carefully and you can still hear some audiophiles refer to the record
stylus as ... "the needle." Although we are not about to quibble over
semantics, we would like to go on record, so to speak, as observing that the
stylus of today bears no more resemblance to a needle than it does to a
ten -penny nail. In fact, it is probably the most skillfully assembled, critically
important component in any high fidelity system. It must maintain flawless
at the whisper contact with the undulating walls of the record groove
weight tracking forces required to preserve the fidelity of your records
through repeated playings. We put everything we know into our Shure
and we tell all about it in an informaStereo Dynetic Stylus Assemblies
tive booklet. "Visit To The Small World Of A Stylus." For your copy, write:
-
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Shure Brothers Inc.
222 Hartrey Ave., Evanston, Ill. 60204
Check No. 61 on Reader Service Card
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AmericanRadioHistory.Com
ksi
the people like it, most of them being
somewhat less than musical connoisseurs.
Good or bad? Well, in works like
this you can't really say. No standards
exist, unless you think they do. (I don't.)
If some people are shocked by assorted
blues and stage stuff in a Mass-well,
there's plenty of that around today,
and not invented by Bernstein. If others,
with higher brows, decry the slightly
lowbrow approach, then they, too,
should shop elsewhere. You can write
good music in lowbrow style, remember, if you are good. Bernstein
had every right, etc. As for dancing,
and light shows, and taped elements,
all that is merely par for the course
in any up-to-date big production these
days. So you can't gripe on any of these
counts, nor on most others of an a priori
sort according to earlier standards.
Ah-but you can listen to the music,
though it is only part of the show,
The $300°°
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With all the "great", "new ', "fantastic",
"innovative" things everyone's claim-
ing, how do we prove we've
got something remarkable?
Lend us your ears. And
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Walk into an authorized
LDL high fidelity dealer
with a favorite record or
tape-hopefully, a demanding one. Ask him to hook up your present (or future) amplifier or receiver and
a pair of LDL 749 reflecting speakers.
And listen.
Listen to the "speakerless' clarity of a
multiple -transducer crossoverless system using the finest components. If your
record's got fundamental bass, the fundamental's what you'll hear, up to and
including the attack of drums and
strings. And as for highs, you won't just
listen to them-you can pick them apart:
violins, trumpets, piccolos and moreeach clearly defined.
But good stereo (or quad) is more than
frequencies and transients put in their
place: it's a spatial phenomenon. Which
is where the LDL 749 really excells.
Precisely combining forward -radiated
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and there the description isn't difficult,
though judgment is. I enjoyed Mass
a lot (following the action and text
throughout in the big book) and so will
you. But don't expect anything very
modern. It's old fashioned as all getout! Straight from the Bernstein heyday
-when else?-the
1940's.
You can't help hearing On the Town,
West Side Story, Fancy Free, augmented and upgraded, at times
ennobled, the 40's pop nicely interlarded with 1940's middle -Stravinsky
in the familiar Bernstein manner,
and Aaron Copland (middle period)
peeping around the corner every 30
seconds. Hard to believe. And all this
in spite of the superficial modernities
of tape music, multi -media staging,
and eye -stoppers such as the ultramodern Alvin Ailey American Dance
Theatre (they work with the likes of
John Cage).
After all, Bernstein is getting on and
settling down, long since comfortably
established in his dynamic role as
godfather to the arts, united. Still
interested and excited by what's new,
of course. But in his own work, both
composing and conducting, he tends
now to be conservative. He harks back
to the heady days when pop joined
hands with the Philharmonic in his
very person. Nostalgic, and even a bit
quaint.
Yet the man is a fine musician and
I found most of Mass, mixing pop and
classical performers in the old Bernstein tradition, to be economical and
in consistent taste-consistent with
itself. But sometimes I grew embarassed,
and not for the reason's you'd think.
I cringed at Mr. Bernstein's rock-awful.
Not remotely rocklike, was my reaction,
and I suspect the younger rockers will
agree. Off the beam, and the indignity
is not to the classics but to the pop
music he is supposedly honoring. In
fact this is the chief criticism of Massit demeans its pop music more than its
classical, a sort of unintended Uncle
Tomism. Curious.
For all the credits-Producers,
Choreography, Musical Director, Production Coordinator, Additional Texts,
Celebrant, Settings, Costumes, Lighting, there are confusingly few references
to the musicians involved. The Norman
Scribner Choir and the Berkshire Boy
Choir get credit but the multitudes
of others seem to be intentionally
anonymous, neither on the album
cover, the discs nor the cover and flyleaf of the booklet. Contracts? Or just
a new trend?
Performance:
The one-and -only original.
Sound: B +
60
AUDIO
APRIL 1972
Canby's Capsules
QUADRAPHONIC DISCS
Edward Tatnall Canby
Stan Kenton and His Orch. Live at
Brigham Young Univ. Creative
World ST 1039, 2 discs, (SO),
$ 13.98. P.O. Box 35216, Los Angeles,
Calif. 90035.
Quadr. sound is going to be big in "live" recordings-it takes you there, with the
audience. Curious perspective in this one but OK: audience is mostly in front, but
band is all 'round. (Where are you? Who cares!) Real participation, if you like Ken ton's fat, portentously brassy and dissonant mod. jazz. My ear says it's outa the
steely 1940s.
Barbra Streisand-Stony End. Columbia CQ 30378, (SO), $6.98.
Yes-Barbra plays OK in stereo (for an extra buck). In this big-time slickpop,
Morton Sobotnik: Touch. Columbia
MO 31019 (SO) $6.98.
"Touch" is all -electronic (Buchla), 2 sides long; this type music has no "front" or
"rear," ideally needs equal power all way 'round. SQ does good job adding spatial
interest.
Dynaco 4 -Dim. Stereo Demonstration
Disc (#2). Pop and Classical. Dy naco SPV-7, (DY), $2.95.
Fun/games. Play this via SQ, E -V or what -not and it'll sound OK. Via Dyna-type
matrix, an emphasized separate rear space; via SQ, more rounded, with more stereo
in front. One side is classical: "Hallelujah" (Handel) in mono, stereo, Dyna (why
bother?); superb Mozart strings in tank -like big space; the usual Berlioz (Requiem)
4 brass choirs (no-can't tell which is which, but that is the "live" effect too); a
4-
way sound merely rounds things out abit. Barbra is vaguely front, slick stringls etc.
vaguely elsewhere.
mvt. from Tchaikovsky 4th. All from Vanguard. A useful demo on any four-way
system.
Mercury 4-2-4 Matrix Demo Disc
MO-1 (not for sale).
Snitch this if you can-it's terrific. Superbly played music (Mercury) and fine
four-way sound via E -V matrix. But note-all is Mercury's derived 4 -channel,
from 3 -ch. originals! Nicely proves that 4 discrete channels aren't necessarily required, tho obviously they offer maximum recording versatility. Handel, Brahms,
top -rank playing.
Stravinsky (2). Tchaikovsky, Leroy Anderson
....
job from Way Out There, done up in Dynaquad. (It plays SQ with the
same arena -type big sound.) Fat, tubby, dynamic band, with tuba, playing polkas
and waltzes, sort of German-Polish-U.S. Goes nicely with beer.
Dick Rogers and his TV recording
orch. play polka varieties. KL Recording KLP-6, (DY), (Box 55, Huber tus, Wis. 53033.)
A very pro
Bach: St. John Passion. Raskin, Forrester, Lewis, Shirley, et al., Singing
City Chorale, Phila. Orch. Ormandy.
Columbia M3 30517, stereo, $ 17.98.
Ormandy's ears are always open-this monster performance, outwardly in old
big - oratorio tradition, is cleverly updated-modern, faster tempi, correct continuo
accpt. (with a loud, wiry harpischord), chorales sung fast and minus old long pauses.
But the chorus is huge and vibrato ridden, the soloists do their best to sing in pompous Sunday style. Not bad (and the solos are top artists)-if you like the big-time
U.S. approach. For comparison, note the (1966) "authentic" Telefunken job, with
old instruments, etc. Much thinner and cleaner, the recitatives "spoken" lightly,
the chorus lean and accurate. But the sound is distant and flat, lacking perspective.
Cf: (Same). Soloists, Concentus Musicus, Wiener Sängerknaben; Chorus
Vienensis,
Gillesperger. Telefunken
SKH-19, (3 discs), $17.85.
Musik der Dürerzeit (Music
in Dürer's
Cappella Antiqua Munchen;
Studio der Frühen Musik; Monteverdi
Hamburg. Telefunken TK
Choir.
11515 / 1-2, stereo, 2 discs, $ 1 1 .90.
Time).
Josquin Desprez: Chansons, Frottole
& Instrumental Pieces. Nonesuch
Consort, Rifkin. Nonesuch 1H-71261,
stereo, $ 2.98.
Prokofiev: Symphony No.
sical"); Symphony
No.
1
("Clas-
3 (1928).
London Symphony Orch., Claudio
Abbado. London CS 6679, stereo,
$
5.98.
AUDIO
OUR 25th YEAR
Eur. and American performances of similar music c.1500, done with now -standard
musicological authenticity from old ms. or contemp. editions. The Telefunken
"Dürer" album (see cover) is a "best of" combination survey-wonderfully musical,
voices and instruments beautifully balanced, an over-all gentle quality, relaxed.
The Nonesuch music is louder, at higher tension, less well balanced and phrased,
more driving. Good instr. playing, some fine voices, but ensemble is often so-so.
Really excellent Prokofieff! Both the familiar "Classical" and the tough, dissonant
3rd, out of a non -performed earlier opera (1927, the Fiery Angel). Abbado is a
very solid young conductor, letting the music have its say, at reasonable tempi
and without histrionics-yet his phrasing, balance, detail work, are impeccably
musical. Best "Classical" I know, bar none.
APRIL 1972
61
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Audio ETC
Edward Tatnall Canby
the corporate block
GG
HOW LONG will it last?" My
final words, a month ago.
Well, it's lasting, the Corporate Block, and in some ways getting
worse. But, at least in our area, there
are breaks to be seen. And a new
factor has entered into my calculations.
I just made it up. I will call it the 2'
factor, and it is very likely to measure
success or failure to come.
Mainly, what has happened in the
early months of 1972 is a kind of
forced motion, still non-productive,
among the dismally blocked giant
explosions.
Internal
corporations.
Bustups. Realignments. Still-no product. Just mounting pressure, unrelieved by sales. This isn't the happy
outward movement of active trade, a
functioning market with product, distribution, sales, cash, the completed
economic circuit with all currents
flowing! It's still deadlock. And corporate earthquakes, like that in EVR.
Or big legal challenges, like that from
the recent E -V matrix patent.
I cited 21 areas of interest in respect to this blocking phenomenon
last month, and wrote only about the
extra "half' as a refreshing contrastinternational trade. It may be full of
danger and uncertainty but at least
it moves. Products in abundance, distribution all over, sales galore, cash
flowing, if sometimes into the red. Any
business that moves in this fashion, I
U\BLOC <ED
say, is healthy, even if people do lose
their shirts in it (that's competition).
But competition without any business is something else again. Many
products announced, none available.
Competition before the fact, without
consumers, carried on inside industrial empires like Medieval warfare
out of impregnable castles! Far too
many new systems, all aiming where a
few will fit. And all of them mutually
-deliberately-incompatible and irreconcilable. That's the shape of the
corporate block, and to the consumer
it's for the birds.
The two particular areas I have in
mind are, of course, our immediate
and close interest, the four -channel
field, quadraphonics/sonics, and the
larger, more revolutionary area of the
so-called TV cassette and the TV
disc. (Will somebody please invent a
name to cover both?) We in audio are
so involved in quadraphonics that we
tend to ignore the larger, more fundamental warfare going on 'way up there
over our heads in respect to the big,
picture -filled cassettes. We aren't
much bothered, from day to day, by
the all-embracing, productless stall that
has developed there among the corporate giants; it's not our money nor our
headache.
But, stall or no stall, the TV casstill has an enorsette (and disc
mous potential. It is still going to
...)
62
revolutionize our electronic lives,
though it will take a little longer than
planned. It has huge, unsuspected
depths of meaning for mass communication in the future, all too little understood, even among those who do the
dry -run promoting today. (That's
part of the trouble.) We will be
involved, all of us, merely as people.
And, mind you, every TV cassette
(and disc) that ever plays into a TV tube
or light -screen equivalent, by whatever system among the many, will
carry with it an audio signal and, more
likely, two. So we will be there. Moreover, the same corporations that fight
our small-scale quadraphonic battles
are involved in the more deadly
hassling in TV. It really is one big
problem. The characteristic symptoms of
the Corporate Block have appeared
equally in these two areas, the larger
and the smaller. But ours is beginning
to break.
Just maybe, we are small enough to
get by. And we are much less radical
than they are, in their play -it -yourself
television systems. We build on familiar
ground-home hi-fi, stereo, components
and so on. We are adding merely
wrinkles, if good ones. They are floundering in a vacuum of uncertainty,
despite all the propaganda. They don't
really know
or they disagree. We
aren't so sure where we're going either,
but we have strong hunches, well
founded. Our innovations are much
closer to the ground, nearer to present
consumer habits. WE aren't tossing any
TV newspapers onto suburban front
porches, or sending the kids to borrow
some comics from the TV library
down the street! Radical stuff, that.
So-we can see light. Maybe we're
going to unblock.
Significantly, I note that, though we
also have too many systems, ours are
not many too many. And though ours,
too, are incompatible, we are able to
see (dimly) some workable approaches
to compromise, whereby we might use
them all, at least in part. I don't see
that among the TV cassettes.
The day I watch a Sony color cassette
plug into an EVR player, followed by
an RCA SelectaVision laser tape,
I'll concede that workable compromise
has been achieved among the videocassettes. I'd even settle for less.
If the relatively similar magnetic tape
entries would somehow stretch their
quarter-inch and shrink the one -inch
tape to fit the half-inch player, for a
species of compatibility, I'd say part of
the big battle was won. Even without
...
AUDIO
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OUR 25th YEAR
APRIL 1972
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RCA, CBS' and Teldec. But it won't
happen. It can't.
I think I can envision the quadraphonic equipment that is going to
head up our necessary compromise. It
will be practical and possible. That's
the big difference. But first let me look
at that curious figure, 21/2, which is
crucial to my perception.
For instance, what would you say is
the optimum number of competing
systems, using different approaches,
that can exist, with active business,
in a particular consumer area? More
than one, obviously. We have 'em
everywhere. But how many? Well, I'll
tell you. The number is 21/2.
Look around for a moment. How
many 35 mm still picture cassettes are
on the market? 21/2. The original Kodak
film cassette, standard among hundreds
of film and equipment manufacturers
for forty years or so. And now, Poloroid,
a specialized but widely available film pack cassette. And, to fill out the extra
half, a few sub-miniature film cassettes
which have managed to endure, on a
small scale.
How many 8 mm consumer film
systems? 21/2. The original 8 mm film,
the Super 8 and the Single 8, half-twin
to Super 8 and compatible in the projector. More than two, but less than
three.
How many sound systems for professional film? Magnetic and optical,
two basic approaches. But optical is a
pair of half-twins again, variable
density and variable width, compatible
in the playback. That makes 21/2, if
you discount such refinements as stereo
and Cinerama. Once again, the systems
are made workably compatible via playback/projection equipment. They live
together.
How many disc systems? The LP,
the 45 and the semi -retired 78, still
alive though out of production. 21/2.
These, too, meet in the playback equipment, which can take them all.
How many home sound media?
Disc. Tape. With extra subdivision into
cassettes, reel-to-reel, cartridge, to
make up the extra half. 21/2-and still
again, they meet in the playback area
via componentry designed to fit the
need.
How many radio systems for public
broadcast? AM, FM, and a small area
of citizens' radio and walkie-talkie.
21/2. Or maybe you'd like to put it down
as entertainment radio-AM, FM, and
stereo multiplex, a halfway offshoot.
To be sure, my categories are somewhat arbitrary. But there is a real
point to be noted.
Go further. Today, our groups of
systems tend more and more to inter-
penetrate-films,
cassettes, records,
tuners, projectors and so on. You can
find more 21/2 examples within these
areas. How many audio tape cassettes?
21/2. The Philips musicassette. The 8 track cartridge, and as an extra half,
the obsolete 4-tracker and such side
operations as the PlayTape cassette.
Not to mention the new HiPac.
How many disc speeds? 21/2-the
45, the 33 and an occasional 16 or 8
in specialized areas. How many home
tape speeds? More than two but less
than three! 71/2 and 33/4 for reel tape,
1'/s for cassette. You can split them 3
ways if you want. Or call it 21/2.
OK-I'll let you have it. How many
political parties? 21/2, what with "3rd
party" splinters. How many major
leagues? I could go on & on. It is obviously a way of life with us. If you
don't like 21/2, call it two -plus. How
many Presidents? 21/2, if you're thinking
hard about Mr. Agnew and Mr.
Kissinger...
AUDIO
64
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.
Quite seriously, I suggest that the figure 21/2 represents the normal acceptable
complement of non -compatible
or
semi -compatible systems, within a
given consumer area. Deny the rule if
you dare.
We will usually take on more than
one system. But not much more. That
is the important conclusion. And so
we may derive some quick futurist
info from the cloudy crystal ball. If
we aim for the 21/2 figure, we're going to
be OK. But more systems-no! Tell
that to the TV cassette people.
Thus in the quadraphonic area things
look ultimately good. Because the
tendency is now towards consolidation
at just about this level of overlap and
redundancy-however tough the infighting at the moment. Not so in TV.
There, things look really bad. Is it a
dozen systems, or 20? And virtually no
chance of compatibility.
I think, then, that we are going to
live with our two basic four-channel
approaches, the discrete and the matrixed. Both of them. Discrete naturally
favors tape. Matrix is most favorable
on disc, though it can go in cassettes
too. There are good advantages each
way and room for motion.
On a narrower scale, I think too
that we will go along with two kinds
of quadraphonic disc, in case RCA
comes out with its modified JVC wide band supersonic model, the discrete
disc. They are incompatible. But the
playback equipment, in time-honored
fashion, can be built to take them both,
all in the same package. A single cartridge and turntable (putting aside the
present need for a modified stylus/
cartridge to play the RCA disc),
OUR 25th YEAR
APRIL 1972
e., Sun Valley, Calif. 91352
© 1972 Supersco
feeding into a dual decoder unit, or
built-in circuitry, for matrix and
discrete. It won't be too complicated
in the long run, nor too ruinously
expensive, what with ingenuity and a
few ICs to take over some of the load.
We do these things already. My Lafayette 524 quadraphonic rear -speaker
amplifier, just out, already has two
built-in decode circuits, arid it isn't an
expensive unit at all.
In fact-there can be automatic
switching, from one type disc to the
other, actuated like the FM stereo
light via the supersonic signal on the
discrete -type disc. How's that! All
this, you see, is clearly within the
possible, and therefore probable. I
think the 21/2 principle indicates that
most of us would welcome a real
business test of these two discs in terms
of workable home equipment, plus
discs available on the market. And
may the best system win-in the home
and in the market place.
But not before the matrix disc itself
has settled down and the matrix
fights are put aside. Frankly, most of us
are tired of the corporate rows in this
area. Last fall, a reluctant getting-together of the major matrix interests
made it clear that a single decoder
circuit can in fact decode virtually
any of the variant matrix systems into
satisfactory four -channel sound. That
was good news-but the required sequel
is mandatory-get on with it!
In the public interest, and in the face
of RCA just outside the door, the matrix
people will just have to forget their differences and come to an agreement,
however much somebody's skin is peeled
off. E -V has its patent. Columbia has the
music. If these two have accommodated
their differences by the time you read
this, the rest of the disc industry will
soon get nicely in line-either behind
the unified matrix idea, variable but
playable on all matrix decoders, or
behind the discrete RCA disc, when &
if. And so we'll be in business at last,
the Corporate Block Unblocked.
I haven't heard any good news lately
-I've been elsewhere. But I'm optimistic
simply because I can see that the
21/2 factor really will work in quadraphonics, given half a decent chance. The
stage is thus set. If the quadraphonic
disc untangles itself and gets on the
market-whether in one form or twothe rest will fall into place. Much of it,
actually, is already there in advance.
Hope springs eternal, and our equipment makers have gone far out ahead,
with four-way hi-fi all over the place.
just waiting to play whatever comes
along.
So-Big Corporations-let's
get Unblocked. It's about time.
you
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APRIL 1972
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Weingarten Looks At
the bangla desh album
falling," cried Chicken
Little, and, as usual, the bleeding
hearts talked up an alarmist
storm. Also, as usual, no one actually
did anything to help the situation. But
the day was saved, accidentally, when
the wayward sky wars bolstered by all
that hot air.
Admittedly, that's kind of a bastardized version of the childhood tale.
Nonetheless, even if the sky isn't really
falling, the level of sanity seems to befor lessons of history go unheeded as
mankind continues to indulge in maniacal wars, consuming people as easily
as Americans devour sugary, useless
breakfast cereals.
The latest insanity was the India Pakistan thing, a skirmish that hardly
lasted long enough for most Americans
to work up a good cocktail party
routine. Yet long before the war that
resulted in East Pakistan's transformation into Bangladesh (Bengal nation),
there were millions of victims there, the
hungry and homeless refugees from the
storms that racked the area.
Bleeding hearts by the score sounded
off. As in the days of Chicken Little
THE SKY is
though, no one acted. Except ex -Beatle
George Harrison.
Sitarist Ravi Shankar, a Bengali,
last summer proposed to Harrison the
notion of a benefit concert, not as a
political propaganda but as a means of
aiding the refugee hordes. Harrison
within weeks rounded up some friends,
including Bob Dylan, ex -Beatle Ringo
Starr, guitarist Eric Clapton, and blues
singer Leon Russell. Result: the historic
day and night concerts held August 1,
1971 at Madison Square Garden in
Manhattan.
Shankar originally had visions of
making perhaps $50,000 for the
refugees, but the displaced persons
actually received $243,000 from the
concerts themselves. And, according.
to Allen Klein, president of Abko Industries, which governs the affairs of
Apple Records, the three -disc recorded
package of the event is expected to
raise over $14,000,000 more by year's
end, the money to be administered by
the United Nations Children's Fund.
The recordings almost didn't make
it into the public sector however. As
the chill of winter set in, the corporate
temperatures and blood pressures were
66
rising; wranglings over profits and distribution of the super -sessions hit the
boiling point, with settlement coming
only last November after Harrison took
to the airwaves, via Dick Cavett's late night video talkathon, and detailed the
trouble he was having controlling the
royalty arrangements.
Thus, finally, the refugees benefited,
and so did all rock -pop audiophiles, for
THE CONCERT FOR BANGLA
DESH (STCX 3386) is a gig that captures all the excitement of the extravaganza while neatly summing up
the music of the 60s. And, unlike many
live recordings, sound is excellent
throughout, perhaps because two dozen
microphones were used, and maybe because the performers (all of whom
donated their services) were conscious
of the need for a quality playback to
ensure more sales.
The boxed set, which includes a
magnificent 64 -page booklet filled with
color photos of the participants, follows
the natural flow of the concert, giving
an on -the -spot feeling to the listener.
It opens with Harrison's somewhat
elongated introduction and Shankar's
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OUR 25th YEAR
APRIL 1972
© 1972 Superscope, Inc., 8142 Vineland Ave.,
setting the mood for the event via a 16 minute "Bangla Dunn" duet with Ali
Akbar Khan, master of the sarod.
Shankar, noting that the concert is nonpolitical, explains to the crowd that
Eastern music is misunderstood (obvious when the crowd applauds his
tuning) and that this song is intended
to "free from pain and agony"
those
suffering in the Pakistan -India area.
Harrison excels on "Wah-Wah,"
"My Sweet Lord," and "Awaiting On
You All," and Billy Preston offers
soul -rock by means of "That's The Way
God Planned It." Next comes Ringo
Starr's version of "It Don't Come Easy,"
a vocal curiosity proving once and
for all that he can't sing and is just
a latter-day Fabian. Harrison is then
joined by Russell for a smooth-rough
vocal duet, "Beware Of Darkness."
After Harrison introduces the band,
he sings "While My Guitar Gently
Weeps," a rendition which includes
lengthy guitar solos by Clapton and
himself. Russell borrows from the
Rolling Stones next, talk -screaming
his brand into "Jumpin' Jack Flash"
and segueing "Youngblood" into it.
"Here Comes The Sun" finds Harrison
again using both vocal cords and guitar
chords.
Before Harrison closes the concert
with "Something," a gas by any
standards, and his hit single, appropriately enough, "Blangla Desh," there's
an explosion. Not a literal one, but one
of crowd enthusiasm and ecstasy stemming from Dylan's appearance.
Backed by Russell on bass, Harrison
on electric guitar, and Starr on tambourine, Dylan wails on five of the
tunes few expected to hear him do again
in live concert, having cut his in -person
shows to the bone, seeking privacy as
the end-all in lifestyles.
Dylan's voice is countrified, almost
hillbilly in character, not unlike that
of a decade ago. And despite his rebel
blood thinning through the years, all
the old feeling seems to bubble to the
surface as he pours out "Blowin' In The
Wind" and "A Hard Rain's Gonna
Fall." Sandwiched between are "It
Takes A Lot To Laugh, It Takes A
Train To Cry," and the troubador's
section concludes with "Mr. Tambourine Man" and "Just Like A
Woman," the latter being joined vocally
by Russell and Harrison.
There have been name super -sessions
put before the public, many of them
rip-offs; never has there been one as
well -constructed as this. It makes you
think there's really hope for popular
music-and that maybe the sky won't
Æ.
fall after all.
AUDIO
APRIL 1972
67
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Somethin' Else: Danny Davis and the
Nashville Brass. RCA PQ8-1692, Q8
four -channel stereo cartridge, $ 7.95.
RCA has released nine new Q8 cartridges, the first since the initial 70 -odd
issued some time ago. You may recall
I took RCA to task for what they did
to their classical Q8 recordings, and it
is perhaps significant that no classical
material is in this new batch. In fact I
have been assured by a highly placed
RCA official that any classical Q8 cartridges henceforth will be properly recorded for ambient rear channels. Hoorah! I was back -ordered on the other
8 cartridges in this release, but if the
rest are as good as this, we have made
some good progress. I know nothing
whatever about the performers here,
nor is country western music my bag,
but they are quite obviously darn good
musicians in their field. Soundwise
this Q8 tape is head and shoulders over
RCA's previous efforts. As I noted in
my earlier reviews, there was nothing
basically wrong with the RCA brand
of pop "surround" sound, but it was a
bit static and lacked the "motion dynamics" of the Enoch Light four -channel stereo. This is fine, and with an
excellent apportioning of instruments
to each speaker, to the extent that, with
the overall clean sound, I really enjoyed
some of this CW music! For the second
generation of RCA Q8 cartridges, an
auspicious start.
The World's Greatest Jazz Band of
Yank Lawson and Bob Haggart.
Project Three PR4C-5039, Open reel
four -channel stereo, 7Y2 ips, $14.95.
This is one of the new four-channel
stereo tape releases on Enoch Light's
"Project Three" label. I can't say enough
good things about this recording. The
title sounds like the boys must be on
an ego trip, but believe me, with such
stellar personnel as Yank Lawson, Bob
Haggart, Billy Butterfield, Lou McGarity, Carl Fontana, Bob Wilbur, Bud
Freeman, Ralph Sutton and Gus Johnson, Jr., who can argue with them?
Everyone of these men a virtuoso of
his chosen instrument. Individually
they are brilliant. Their ensemble playing is superb, their overall musicianship impeccable. The basic sound might
be described as "Dixie" and "modified
Dixie." In any case they are both ex 68
citing and tuneful in such numbers as
"Love Is Blue," "I'm Prayin' Humble,"
"Alfie," "Wichita Lineman," and that
big Dixie rouser, "South Rampart Street
Parade." The arrangements used here
are very important, because Enoch
Light tells me they were written with
the knowledge that the recording was
to be in four -channel stereo, and in
this way maximum exploitation of the
medium could be achieved, rather than
with the usual method of creating the
four -channel tape from scratch on the
mix -down from 8 or 16 tracks. The effect is stunning and with the instruments seemingly in their "logical"
positioning at each speaker, although
of course, logic can't be a factor in
this kind of recording. The overall sound
is ultra-clean and brilliant, miked closely
but with that right leaven of reverb to
give it great presence. A winner in every
sense and a. fabulous introduction to
the medium for four -channel "first
timers."
Music From Great Film Classics.'
Conducted by Bernard Herrmann with
the London Philharmonic Orchestra
Ampex/London-L74144, open reel,
$7.95.
I'm glad to see that London has
evidently become attuned to the remarkable talents of Bernard Herrmann,
honoring him here with a potpourri
of some music from his film scores and
giving him conductorial assignments
as well. Mr. Herrmann's recent recording of Holst's "Planets," was
warmly praised by most critics. On
this tape we hear excerpts from "Citizen Kane," "Jane Eyre," "The Snows
of Kilimanjaro," and "The Devil and
Daniel Webster." This is music a far
cut above ordinary film scores. It is
well constructed, cleverly scored, and
is properly evocative-as good program
music should be. Understandably, Mr.
Herrmann elicits a fine performance
from the London Philharmonic, who
obviously play his music without condescension. The sonic values are fine
7Y2 ips,
too, with exceptionally good balance,
spacious acoustics without blunting
orchestral detail, wide dynamic and
frequency range and a moderate level
of tape hiss. One of the best-processed
tapes in some time, and very pleasant
listening.
AUDIO
E
Check No. 69 on Reader Service Card
www.americanradiohistory.com
AmericanRadioHistory.Com
Bert Whyte
OUR 25th YEAR
APRIL 1972
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J
NEAR HERE
Jazz
FOR THE UTMOST IN
Ira Sullivan Quintet: Nicky's Tune
Musicians: Ira Sullivan, trumpet; Nicky
Hill, tenor saxophone; Jodie Christian, piano; Victor Sproles, bass, and
DISCOUNTS
ON NATIONALLY
ADVERTISED
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Wilbur Campbell, drums.
Songs: My Secret Love; When Sunny
Gets Blue; Nicky's Tune #2, #3,
and Wilbur's Tune.
Delmark DS -422, electronic stereo,
STEREO
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RSC
-
Best in the West
This gloriously uncommercial LP
containing but five cuts, two of the
same tune, was recorded from 5:00 to
8:00 a.m. on December 24, 1958 in
Chicago. The set is dedicated to the
late tenor saxophonist Nicky Hill who
died five years ago. Hill is listed here
as a sideman with the tremendously
talented Ira Sullivan, but the record
is actually more Hill than Sullivan.
An attempt to resurrect BeBop (Re Bop), a jazz genre which flourished
from roughly 1943-1953, the tunes are
in that style of taking bee hives of
notes to say what you have to say.
Coupled with this rhapsody is a pungent humor brimming with quips and
puns, witticisms and sarcasms, the
so-called trademarks of bop which
essentially was a way of looking at
life and punching musical holes in
hypocrisies.
Delmark has brought bop back, but
so woefully altered to electronically
simulate stereo that the reproduction
is unsound and tincannish, with nothing
left to do but turn up the volume for
that extra -sensory perception audio
buffs crave. Although apparently covered with a membrane, the music
breaks through nostalgically, Sullivan
and His Quintet playing unpretentious
straight -ahead bop that warms the soul.
"My Secret Love," a tune popular
at that time, is taken at break -neck
speed with Hill out front, very much
alive, and Sullivan scittering above
him, the two musicians speaking openly
of their romantic interests. The truth
will out, sparkling Sullivan shimmying down the scale, as firemen down
a pole, and sounding somewhat like a
cross between Art Farmer in tone and
Freddie Hubbard in technique. Pianist
Jodie Christian is capricious, cleverly
courting triplets on piano, while drummer Wilbur Campbell strikes his cymbals on the downbeat and approaches
the tune with the pomp and stance of
a Bengal lancer.
The most outstanding cut comes
early with a totally inspired original
70
BluesMartha
treatment of "When Sunny Gets Blue,"
which has to be one of the prettiest
tunes ever written. Sullivan states the
theme poignantly, Hill instilling it
with a velvety, crepuscular tone, then
picking it up at the bridge and embarking on a subtle journey which tastefully leaves things to our imagination,
spreading it over with a mahogany
wash shaded with violet fading into
raw umbre. Tenorist Hill plays in
octaves with a yawning cavern of a
tone in the tune that makes the album.
"Nicky's Tune," of which there are
two takes, is traditional bop, #2 taken
at a more sprightly gait and held to be
this listener's choice, as #3 tends to
drag and sound a bit flat by comparison. It is typically bop with lots of stop
and go and soloists converging octaves
apart only to disperse again. That the
rhythm section is vital to bop is evident
here as the drum shoos it along and
Victor Sproles plucks a walking bass
that doesn't excite but acts as an indispensable slide rule to the exercise.
In "Nicky's Tune #2" Hill is looser,
making a blistering attack after which
the two gentlemen simultaneously state
the theme and bring it on home. Jodie
Christian's piano technique, although
measured here, is delightfully unpredictable as he combines treble single
note explorations with octaval spans
that suggest the awesome reaches of
a Phineas Newborn and the bass chordal chromaticism of a Henri Renaud.
An undisputed denizen of the deep,
Christian plums the depths of the keyboard with skillful deep sea dives that
unveil jazz jewels hidden under rocks
and shells.
Drummer Wilbur Campbell's "Wilbur's Tune" is pure bop -propelled by
Hill who generates a bellow and is
given to corkscrew motions on tenor
sax. Sullivan is bold, blatant, blissful,
a most capable technician on trumpet,
horning in at the appropriate moment.
Can you believe he also plays flute,
soprano sax, alto, and tenor?
This LP gives an invaluable perspective to Sullivan's current work
and provides insight into the musician
who played in Chicago until 1960 and
who worked with giants such as Art
Blakey, Sonny Stitt, Roland Kirk,
Eddie Harris, and Herbie Mann.
Sound: C+
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
Sanders Gilmore
Performance:
OUR 25th YEAR
B
APRIL 1972
Classified
FOR SALE
Rates: 254 per word per insertion for noncommercial advertisements; 504 per word for commercial advertisements. Closing date
is the FIRST of the second month preceding the date of issue.
Payment must accompany all orders under $10.00. Use the handy
self-addressed, postage paid card at the back of this issue. When
replying to AUDIO box number ads, send letters c/o AUDIO, 134 No.
13th St., Phila., Pa. 19107. For more information about classified
advertising, circle Reader Service Card # 135.
TV & RADIO TUBES 36C EA. Free 48 page
Color Catalog. Cornell 4215 A University, San
Diego, California 92105.
McINTOSH
2505 VERSUS
Citation Twelve, and Dynaco
winner? Send S1 today for test
with $7.50 yearly subscription.
LETTER, Box 593, Hialeah, Fla.
MARANTZ
32,
120. The
report, refundable
THE HI -Fl NEWS
Stereo
33011.
"HI-FI
FREAKS" and discerning people can
now get the amplifier that's "wiping out" all
other amplifiers at test clinics across the country
and is better than test equipment! Kit only $60.
Send for Free Catalog SWTPC, Box 32040B,
San Antonio, Texas 78284.
SCOTCH RECORDING TAPE, lowest prices.
TAPE CENTER, Box 4305B, Washington, D.C.
20012.
FOR SALE
FOR SALE
MARANTZ 10B $425.00. Lake Oswego, Oregon,
503-636-1 583.
BASF, MEMOREX, SCOTCH reels, cassettes,
8 -tracks. Lowest prices. Satisfaction guaranteed.
S&S Audio, Box 2065, Champaign, II. 61820.
SLIDE POTS is -stock at prices from S .24 each
to S .95 each both dual and single elements.
There are only a few values left (Length of
throw 1.6 inches approx.) Minimum order $100.
Call
213-620-1640.
JBL-C43 rear loading horn enclosures or trade
for D130A's or
Illinois.
C37's.
Dick
Kesler,
Olney,
FREE, discount price list. Nationally advertised
components. Box 18123, Seattle, Wash. 98118.
B&W 70CA, PHASE LINEAR, THE WORLD'S
SCOTCH TAPE #150, 1800 foot, 7" reel,
polyester,
$1.95, postpaid, $22.50 dozen.
(48 at $ 1.75.) Recorders, cassettes, open reel
music tapes (100 page discount catalog 25$).
Saxitone Tape Sales, 1 776 Columbia Road, Washington, D.C. 20009.
'
ADVOCATE
CROLYN
(chromium
dioxide)
CASSETTES in stock. C -60's -S3.20, C-90's$4.00. Also Audiocoustic loudspeakers, Revox,
Crown, Tandberg,
Stax, and many others.
1/4
Professional advice and booklet, "The Stereo
Buying Guide,"' given free to all inquiries.
SoundPro, P.O. Box 2417; West Lafayette,
Indiana 47906.
McINTOSH/JBL-AII
PAIR BROADCAST RIBBON MIKES. Shure
Model 300. Selectable impedances and response
curves. Figure 8 pattern. Complete with lined
cases, dust covers, and Cannon connectors. Like
new condition and appearance. $110 the pair.
Price firm. Phone (814) 226-8879 (Penna.)
MAGNECORD 1048
Professional tape deck.
track. 3 head and fitting for optional fourth
home used only, but excellent for location.
Overhauled Nov. '71. Meets factory specs.
$725.00. Doug Margetts, 243 Woodbridge Ave.,
Metuchen, N.J. 08840.
Preamp
(S
good condition.
C22
200) -MR 71 Tuner (5300)-MC275
all
for
$950.
(5200) -Sell
JBL S8R Olympus-pair $1100. Also Tandberg
64X-$200. Offers. Reply to Box AA2-2.
(5325)-M13
MARANTZ 7C $170, 16B $350, classic
Hadley 622 150w transistor amp $200, Sony
770-2 $500, Shure V15 -II $30, Decca SCYE
$50; all absolutely mint. Reply to Box AA2-3.
TUBES "Oldies", latest. Lists free. Steinmetz,
7519-A Maplewood, Hammond, Indiana 46324.
STEREO TAPES
(reels)
30-70% discount.
Sokol, 3237 South Manor, Lansing, III. 60438.
NATIONALLY
advertised
Audio
Equipment,
Duke
3250
AND TECHNICAL
CONSULTATION
ASSISTANCE with purchase of individually
hand picked, guaranteed lab tested and aligned
custom components from Audio Research Corp.,
A.K.G., Beyer, Crown, Decca, Frazier, Gately,
I.M.F., Infinity JBL PROFESSIONAL, Otari,
Quad, Rabco, Revox, SAE, Stax, Tandberg,
Transtatic. We save you SS with FACSIMILE
REPRODUCTION at Music and Sound Ltd.,
413 Johnson Street, Jenkintown, Penna. 19046
(215) 885-4214.
Instructors,
Musicians.
Engineers,
College
Cost Plus 10%. Stereo World,
Street, Alexandria, Virginia 22314.
ATTENTION!
1800' NEW MYLAR TAPE IN HINGED BOXES;
12 reels for $15.00 postpaid. Send for other
price lists to WIDE RESPONSE, 2926 Bentley
Ave., Los Angeles, Calif. 90064.
FREE
101/2"
reels
and
boxes
(small
hole-fiberglas) $4.50 each postpaid. Write
NRP, 204 19th Ave., S. Nashville, Tenn. 37206.
ORGAN OWNERS & BUILDERS GET THE FACTS
about Electronic and Pipe Organs, kits and
$2.00 for new book
accessories.
Send
"ORGAN BUILDING FOR FUN AND PROFIT,"
by Robert L. Eby. FREE Parts Catalog included.
Newport Organs, Dept. A, 846 Production Pl.,
Newport Beach, Ca. 92660.
-
ADVENT FBC frequency balance control; Ten
octave controls to correct acoustical and recording
problems on stereo systems, are available for
immediate prepaid shipment, $225.00. Each
unit checked for proper working order. Opus
One, 400 Smithfield Street, Pittsburgh, Pa.
15222. (412) 281-3969.
AUDIO
OUR 25th YEAR
HI FI FURNITURE? See Toujay Designs at SEE
70, Hi Fi Expo, 443-A, Park Ave. S., NYC, 10016,
Tues. to Fri. 11-5, Sat. 11-4. Full line brochure
25C.
A77
$350,
McIntosh C22 $ 180,
Radford Monitor Speakers
$300, ADCIOE-MKII S12, 1905 Edison Cylinder Phonograph $200. UMSTOT, 9 Emmaus,
Poquoson, Va. 23362.
REVOX
Marantz
15 5225,
SEND FOR STUDIO CLEARANCE sale list No.
4,
featuring microphones, tape recorders,
equalizers, limiters, turntables, lathes, cutter
heads, and loudspeaker systems. Only professional studio equipment listed. Wiegand
Audio Laboratories, RD #3, Middlesburg, Pa.
17842 (717) 837-1444.
MARANTZ-Model
20 tuner, model 30 integrated amp, both with walnut cabinets. Both
still in warranty and in perfect condition. Retail $1249, will sell and deliver for $795. W. A.
Winchell, 109 Normandy Rd., Oak Ridge,
Tenn. 37830.
APRIL 1972
FINEST SPEAKER AMPLIFIER COMBINATION.
JVC 5011 super preamp. Transcriptor, EPI Tower,
Finest, best
Quad, Electrostatic
specialists.
equipped laboratory in the country. Formerly
supplying to professionals only. Now you can
benefit from the unique services of THE AUDIO LAB, 146 French St., New Brunswick, N.J. 08901
(201) 249-9191.
ALPHAPHONEtm headset-brainwave trainer.
Free literature. Aquarius Electronics, Box 627-S,
Mendocino, Ca. 95460.
QUAD, Radford, Bang & Olufsen Audio components of superb quality for the connoiseur.
Audio Imports, 5557 Versaille Dr., Indianapolis,
Ind. 46227.
INFINITY AND CROWN SYSTEMS -AKG
microphones, UR El limiting, Fairchild equipment,
Finest reproduction possible.
Rabco, more.
Barclay, 503 Haverford Ave., Narberth, Pa.
215/M0-7-3048.
TUBE Headquarters of World! Send 100 for
Catalog
(tubes, semiconductors,
equipment)
Barry, 512 Broadway, N.Y.C. 10012.
PROTECT YOUR RECORDS. Cardboard replacement covers, plastic lined sleeves, 78 and
45 heavy sleeves, hinged record set boxes,
12", 10", 7". Cabco, A-2, 89 East Woodruff,
Columbus, Ohio 43201.
STEAM TRAINS, Sounds of the City, Relaxation,
The Boardwalk, Family Party and many others.
Reel to reel or cassette. Write Caltape, Dept.
F,
P.O. Box 5716, Redwood City, California
94063, $4.95 P.P. 5% sales tax Calif. Res.
BARCUS-BERRY, piano transducers now available to the recording studio, the professional
musician and the serious student. Make piano
recordings of the finest quality on location, at
home, or in the studio. Acoustics no problem.
These piano sensors are being enthusiastically
accepted by the professional recording studios
and musicians everywhere. This piano pick-up
system is a must for the pro. Write for our product
information bulletin. Cath -Mar Recording Service,
17113 Cambridge, Allen Park, Mich. 48101.
Phone (313) 278-2278.
THE FINEST STEREO SOUNDS -On demonstration, Audio Research's Magneplanar speakers and
Dual 75 amplifier, QUAD ESL's, Infinity, Stax,
Decca, Transcriptor,
Thorens, Revox-D S
Audio, 410 East Evergreen Road, Lebanon,
Pennsylvania 17042 (717) 273-6314.
CONDENSER MICROPHONES in easy to build
kits. Free details. Write Electronic Enterprises,
3305 Pestana Way, Livermore, Calif. 94550.
REVOX A77; Eico 3770 AM/FM Receiver;
Miracord
50H/Shure V-15 (II). Improved,
Fisher, 5738 Kentucky, Pittsburgh, Pa. 15232.
71
www.americanradiohistory.com
AmericanRadioHistory.Com
FOR SALE
FOR SALE
PROTECT YOUR LPS. Poly Sleeves for jackets
5C Inner sleeves 40 Poly lined paper sleeves
10C White jackets 25C Postage $1.00. House
of Records, Hillburn, N.Y. 10931.
OPERA TAPES -Great
35 years. Free catalog.
Freeport, N.Y. 11520.
performances
of
Ed Rosen, P.O. Box
past
97,
HI -Fl SALE.
Nationally advertised
amplifiers, tuners, speakers, tape decks, etc.
Discounting of 40% since 1959. Arkay National
1028-05 Commonwealth, Boston, Mass. 02215.
STEREO
BRAINWAVE FEEDBACK. Electroencephalophone
teaches alphawave control. J & J Enterprises,
24120 A 3rd West, Bothell, Wash. 98011.
STEREO SYSTEMS LOW PRICES! Write or call:
Purchase Radio Co., 747 Main St., Buffalo, N.Y.,
14203 (716) 854-2124.
WIRED, SELF -POWERED background music
adaptor to use with your present FM -$25.00.
Thieves Warehouse, P.O. Box 8057, Pensacola,
Florida 32505.
FOR SALE
DEMONSTRATION -Trans-static electroON
static transmissionline monitors, Super Quad
speaker system, Audio Research Corp. D-75
amplifier, Phase Linear 700 and 400 amplifiers,
International
arm -turntable
System
Sound
combination. Paul Heath, 81 Big Tree St.,
Livonia, N.Y., 14487 (716) 346-5630.
PSYCHEDELIC LIGHT Box Kits -From 55.00!
CarrCraft, Dept. 150, P.O. Box 1165, Yucaipa,
Calif. 92399.
.
Original exam
FCC "TESTS -ANSWERS"
manual for F.C.C. First and Second Class License.
-plus-"Self-Study Ability Test" Proven! $9.95.
Satisfaction Guaranteed. Command, Box 26348-L,
San Francisco 94126.
.
.
Audio
amplifiers,
Controlled
multi -directional dispersion; electrostatic, transmission -line Trans -static 1 speakers. Brochures
available, other components. Paul Heath, 81 Big
Research Corp.
Linear, Quad. Decca.
Tree St., Livonia, N.Y.
WORLD'S FINEST SPEAKERS -on demonstration -Audio Research 4 x 6 panels. Infinity SS1
(improved version), 8 Quad system, B&W 70's,
trans static speakers, inquiries invited. Paul
Heath, 81 Big Tree St., Livonia, N.Y. 14487,
(716) 346-5630.
RECORDING TAPE 2400' reel
15.00 dozen,
reel $9.00
dozen. Postpaid guaranteed. Mitchell, Box 444A,
Flushing, N.Y. 11007.
1800' reel
$
$12.00 dozen, 1200'
AUDIO RESEARCH, Infinity, SAE, Decca,
Transcriptors, Stax, Quad, and many others.
The Stereo Set, 1737 Wisconsin Ave., Washington, D.C. 20007 (202) 338-1493.
ALTEC, JANSZEN, THORENS, Revox, Tandberg,
Beyer, Citation, Dual, JVC, Pioneer, others at
LS PX prices. No catalog, quotes only on immediate domestic delivery. Audiofax Unlimited,
Box 7961, Atlanta, Ga. 30309.
GET "MUSIC ONLY" FM Programs SCA Adaptor
fits any FM tuner or receiver. Free list of Stations
with order. Kit $ 14.50 (with Squelch $ 19.50)
Wired and Tested $25.00 (with Squelch $29.95)
All plus postage & insurance. Thousands Sold.
SWTPC, Box 32040A, San Antonio, Texas 78284.
SCOTCH MAGNETIC TAPE, discount Box 167A,
Orwigsburg, Pa.
INTEGRATED CIRCUIT KITS Free Catalog.
FRAZER & ASSOCIATES, 3809 Surfwood Road,
Malibu, California 90265.
TUNER,
SAE
Bose, Revox,
preamps,
-
REVOX A77 MKIII DECK.
$489 factory new,
Dual, Sony. Write for details: CUSTOMCRAFT
SOUND, 202 W. Fayette St., Baltimore, Md.
21201 (301) 727-1134.
-
CAPITOL RECORDING TAPE -Open Reel
Track -Discount Prices. FORDHAM
Cassettes
RADIO -265 East 149th, Bronx, N.Y. 10451,
-8
Dept. T.
KIT makes strong smooth cassette splices
without splicing tape. $4.00 postpaid. Larry
Funk, Box 21035, Washington, D.C. 20009.
FOR SALE: E -V Patrician Model 700 Loudspeakers, Two in perfect condition $700.00 each.
Frazier Equalizer Model SAE -5300.00; Two
Sony C -37A microphones like new- $150.00 each;
B&O Model 200 Stereo microphone -S 100.00;
Ampex 350 Deck only with Stereo Heads and
spare set FT mono heads -5700.00. Ed Gately,
Meadows Lane,
Haverford, Pa.
6
19041
LA -5-7068.
GUARANTEED USED EQUIPMENT LISTING
Revised weekly -Send a self addressed, stamped
envelope to: AUDIO CONSULTANTS, 517 Davis
Street, Evanston, Illinois 60201.
MARANTZ MODEL 20B TUNER. Less than
50 hours use. $590.00 -cost $695.00. F.
Williams, Box 4557, Ecorse, Mich. 48229.
SHURE V15-11 improved, $47 and old cartridge,
shipped prepaid. STEREO Shop, 1209 1st Ave.
SE, Cedar Rapids, Iowa
52402.
LOW, LOW PRICES, on Audio Equipment, L.P.
Records, and Tapes. All factory fresh, 1st quality
items. Trained personnel at your disposal for
audio consultation. We accept Master Charge.
Write for FREE CATALOGS to Mr. A, Dept.
AMO at SMG DISTRIBUTORS, INC., 46-35 54th
Road, Maspeth, N.Y. 11378, or call (212)
786-3337.
HARPSICHORDS AND CLAVICHORDS -New
Harpsichord, curved bentside, uncompromising classic construction and detail,
5355. Other kits from $125. Send for free
brochure. Zuckermann Harpsichords Inc., Dept.
R, 160 Sixth Avenue, New York 10013.
Flemish
HI-FI
DISCOUNTS.
Free
catalog -Western
Electronics, 7121 Rich Ave., Newark, Calif. 94560
72
Infinity,
by appointment, only with John Vogt of Stereo
Exchange, Manhasset, Long Island, N.Y. 516-
KITS, complete or cabinet
published designs. Amplifier
at great savings. Catalog 25C.
Box 30312, Santa Barbara,
JAPAN HONG KONG DIRECTORY. World products information. $1.00 today. Sekai Shogyo
Annal, Hillyard, Washington 99207.
LOWEST Prices Electronics Parts. Confidential
Catalog Free. Knaco, 3174 8th Ave. S.W., Largo,
Fla.
33540.
-
COUNTRY RECORDS and tape cartridges
fiddle tunes, blue grass, polkas. Free circular.
Write Jim O'Neal, Box A50, Arcadia, Calif.
91006.
BUY DIRECT FROM ENGLAND'S HI-FI MAILORDER SPECIALIST! Save on SME, lak,
Acoustical, Goldring, Decca, Bowers & Wilkens,
Thorens, Tandberg, Revox, Gold Speakers,
Garrard, BSR Dual, Lowther, Wharfedale, KEF,
Celestion, Transcriptors, Radford, etc. Insured
shipping quotes free or send $2 bills for catalog
($3 airpost). Goodwin Ltd., 7 Broadway, Wood
Green, London N22. Visitors welcome to showrooms.
FREE 64 PAGE CATALOG offers hundreds of
recordings of rare renaissance, baroque and
classical music. Some records priced as low as
S1.00 each! All late recordings. In stereo only.
Musical Heritage Society, Box 932-AU, New York,
N.Y. 10023.
HEAVY DUTY 12" ANTI -STATIC TURNTABLE
MAT. $4.95 postpaid. Creighton Audio labs,
740 Haven Pl., Linden, N.J. 07036.
SOUND SYSTEM INTERNATIONAL presents a
revolutionary radial track tone arm and turntable. Brochures available. Paul Heath, 81 Big
Tree St., Livonia, N.Y. 14487 (716) 346-5630.
DISCOUNTS -STEREO COMPONENTS & SYSTEMS. Lowest possible prices on quality brands.
For fastest service, Lowest cost -get our quote!
Redwood Stereo Co., P.O. Box 2794, San Rafael,
Calif. 94902. (415) 472-3447.
OPERA TAPES -Records "live" performances,
broadcasts. Free Catalog. Hathaway, 49 Merbrook
Lane, Merion, Pa. 19066.
JBL PARAGON, KLH-9s, Infinity SS2, Mac C-28,
C-26, 2100. Crown DC -300, D-40, Marantz 33,
Sony 777-4, Sony TC -440, Thorens 125B,
Rabco, Paul Heath, 81 Big Tree St., Livonia,
N.Y. 14487 (716) 346-5630.
AMPEX MODIFICATIONS AND REBUILDS-2
track to 8 track -Conversion Transistor Electronics -Studio Accessories -Mixdown PanelsBKM Associates, Box 22, Wilmington, Mass.
01887.
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
amplifiers,
LWE, Rabco, B&O, Demonstration
LOUDSPEAKER
only, original and
kits. Factory direct
R.C.S. Co., P.O.
Cal. 93105.
FIRST BREAKTHROUGH IN RECORDING TAPE.
Originally made by America's leading tape manufacturer 2400' mylar, 7" reel, $2.29, 1800' my lar, 7" reel, $ 1.69, 1200' acetate, 7" reel,
S .79. Write for quantity prices, AAE,
218 Columbia St., Utica, N.Y. 13502.
Phase
.
RUBBER STAMPS. One line $ 1.00. Each additional line 500. Good quality. Prompt service.
MOYERS, 3037 Montrose, Chicago, III. 60618.
A. R. amp $185. Also Marantz, Thorens, Quad,
SAE,
BASF RECORDING TAPE .. prerecorded stereo
tapes, postpaid. Stereotone -Tapes, Box 657,
Sterling, Illinois 61081.
365-8585.
and quotes on Hitachi stereo
Inc.,
Disco Electronics,
equipment. Write:
P.O. Box 146, Springfield, New Jersey 07081.
STEREO CORNER will sell most major Audio
Products at 20% off the advertised list price
Freight pre -paid. Send order with check to:
Stereo Corner, 339 Park Ave. So., Winter Park,
Fla. 32789. Check will be refunded by return mail
if we are unable to fill order.
INFINITY,
THE
FREE literature
OVER 20 YEARS SUCCESSFUL DISCOUNTING
OF AUDIO EQUIPMENT insures best value and
service. Specialize in Stereo Components. Tape
Recorders, Cassettes, Magnetic Cartridges, Sleep
Learn Equipment, etc. LOW QUOTES. FREE
CATALOG. DRESSNER, 1523A, Jericho Turnpike,
New Hyde Park, New York 11040.
KLIPSCH, TANNOY, BOZAK, MARANTZ,
THORENS, RABCO, No discounting. Superior
Sound, 1801 Brewerton Rd. (Rt. 11) Syracuse,
N.Y. 13211.
MONITOR MARK Ill's
INCOMPARABLE SPEAKERS; Teac automobile cassette players; Phase Linear; Mattes Martin; C/M Laboratories electronics; Decca and
Goldring cartridges stocked. B & 0 1800 tape
deck as new special $445.00; Marantz 22 Receiver mint $340.00. We take trades. Audiocraft,
South Rockwood, Michigan 48179. Telephone:
(313) 379-9945.
IMF STUDIOS AND
OUR 25th YEAR
APRIL 1972
SCHOOLS
RECORDS
SERVICES
EARN College degrees at home. Many subjects.
Ministerial studies, High School Equivalency
Diploma. Florida State Christian College, Post
Office Box 1674, Fort Lauderdale, Florida 33302.
OLDIES -45 RPM original labels and represses
over 5,000 from personal collection for sale.
Reasonable prices. Try me for the ones you've
given up hope in finding. Call or write, Robert
Fenster, 1503 Ave. J, Brooklyn, N.Y. (212)
DON'T PAY the high' mail order prices. Thieves
Warehouse is coming to your area. Franchises
available. Thieves Warehouse, P.O. Box 8057,
Pensacola, Florida 32505.
258-5121.
.HELP WANTED
Serious recordists to make records for five
companies. We train, equip and provide protected
franchised territories. Modest investment required.
Send resume to Mr. Bloch, 418 N. Main St.,
Englewood, Ohio 45322.
EUROPEAN -FOREIGN EMPLOYMENT. Detailed
report on currently available jobs, Europe, Africa,
Australia.
Numerous technical and teaching
positions. $3.00. Eurojob Report, Box 52643-E,
Lafayette, Louisiana, 70501.
spanning theater/
rock concert work styles. Theater producer of
contemporary hit musical seeks audio engineer
to tour road company starting July. Knowledge
of radio mikes essential plus problems of retuning entire show to differing environments. Will
serve as supervisor of IA technicians. Enthusiastic, hard-working sound nut required. High
salary. Inquiries handled in confidence. Phone:
Andrew Mihok (212) 677-1750.
Audio Engineer/Technician
Prestigious small college in New York area seeks
Audio -Visual Director. Must know and be able
to service professional and consumer recording
and sound equipment, serve as college photographer, and be capable of acting as technical
Department.
consultant to Theatre
Salary:
$10,000-$14,000, depending on qualifications
and experience. Reply Box AA2-4.
COLLECTORS JOURNAL -VALUABLE DATA,
RECORD MART 12 issues $3.00 -Record Research, 65 Grand Ave., Brooklyn, New York,
11205.
ALBUMS -Rare,
LP's.
Out -Of-Print
Broadway/Hollywood Recordings.
Georgetown, Connecticut 06829.
SHOW
Free large list.
OLDIES -45 RPM. Original hits. Catalog 50C.
C&S Record Sales, Box 197, Wampsville, N.Y.
13163.
CATALOGS. Broadcasts, soundtracks. Personalities of Thirties, Forties. Box 225, New York, N.Y.
10028.
ORIGINAL HIT RECORDINGS. Popular entertainers 1920's, 1930's, 1940's New LP's.
Low Prices. Fast Reply. DIBS-AD, Box 388,
San Pedro, Calif. 90733.
RECORD COLLECTORS -Deleted, discontinued,
"hard -to -find" LP's. Soundtracks, shows, classical our specialty. Send your want list to Dept. A,
The Record House, Inc., 1101 Polk St., San
Francisco, CA 94109.
DELETED L.P.'s. Get on my sales list. Send
name & address. Vincent Scaparro, 904 Allerton
Ave., Bronx, N.Y. 10469.
INVENTIONS WANTED
FREE "DIRECTORY OF 500 CORPORATIONS
Seeking New Products." For information regarding development, sale, licensing of your
STEREOS
Automatic Radio,
Blaupunkt, Boman Auto
radios -Tape players Dual, Garrard, PE Record
Changers, Sony Superscope, Roberts Norelco,
Craig Tape recorders, Bogen, Grundig, Telefunken,
Shure, Pickering, Grado, Cartridges, Auto and
Home Accessories. Unbeatable prices. Write:
MARTY'S, 2414 University Blvd. West, Wheaton,
Maryland 20902.
COMPLETE LIST OF PRICES
FOR top manufacturers of stereo equipment.
Write for quotations on all major brands of
stereos.
STEREO COMPONENT CENTER
465 High St.,
Morgantown, West Virginia 26505
patented/unpatented invention. Write: Raymond
Lee Organization 230-AM Park Avenue, New
York City 10017.
TAPE RECORDINGS
RENT 4-TRACK open reel tapes -all major
labels, 3,000 different. Free brochure. Stereo Parti, 55 St. James Drive, Santa Rosa, Cal.
95401.
MEMOREX recording tape, audio & video lowest
prices, write for free information BERGETZ
SYSTEMS CO., Box 1181, Melrose Park, Ill.
60161.
AUDIOPHILES stamped self-addressed envelope
Check No. 41 on Reader Service Card
BUSINESS OPPORTUNITIES
brings free valuable splicing tips acquired making
10,000 splices while developing improved line
splicers. Nagy Research Products, Box 289,
McLean, Va. 22101.
START small, highly profitable electronic production in your basement. Investment, know-
STEREO TAPES, $4.95 postpaid. CAG, 3606
Nanton Place, Phila., Pa. 19154.
ledge unnecessary. Postcard brings facts. BartaA.M.A., Box 248, Walnut Creek, California
94597.
Make $25,000 with new mailorder plan! Quick,
remarkable results! Only $3! Guaranteed! Limited
offer! Order now!! Goldco, Box 1747, New
York City 10022.
STORE BUSINESS. Audio Hi-Fi Stereo Components. Principles only. Box 122, Saugatuck
Station, Westport, Conn. 06880.
RENT ANY CASSETTE, Cartridge, or Open
Reel prerecorded tape, ALL Labels. Catalog 75C.
Tape & Time, Box 268 St. Ann, Missouri 63074.
OPEN REEL TAPES from our Rental Library.
67% OFF RETAIL. Listings Available. Alan
Enterprises, 5023 Lee St., Skokie, Illinois 60076.
EMPLOYMENT
INFORMATION
NOVELTIES
JAPAN. WORK -STUDY -LIVE in the most fascinating country in the world today. Complete,
SWISS MUSIC BOXES -Movements. Your tune
to order. Spielman, 55 West 42nd. New York
up-to-date coverage of all aspects. Satisfaction
guaranteed. $6.00 ($7.50 airmail). OISHI, 3-8
Toyotama-Kita, Nerima-ku, Tokyo, Japan.
10036.
AUDIO
OUR 25th YEAR
RENT STEREO TAPES $1.50 week. Catalog
25C Tape Library, Box 8126, Washington, D.C.
20024.
CUSTOM'RECORDING SERVICE. Tape and disc.
Stereo and mono. Live and copies. Editing.
Masters and pressings. High quality at reasonable
rates. Joseph Giovanelli, Audio -Tech Laboratories,
2819 Newkirk Ave., Brooklyn, N.Y. IN 9-7134.
LEARN Electronic Organ Servicing at home.
All makes including transistors. Experimental
kit -trouble -shooting. Accredited NHSC. Free
Booklet. Niles Bryant School, 3631 Stockton,
Dept. 10, Sacramento, Calif. 95820.
TRADE STEREO TAPES, $ 1.25 each postpaid.
Minimum three. Tapetrade. Box 2181, La Jolla,
Calif. 92073.
HIGH FIDELITY SPEAKERS REPAIRED
AMPRITE SPEAKER SERVICE
655 Sixth Avenue, New York 10, N.Y.
MAKE FRIENDS. Write Worldwide Tapespondence, P.O. Box 85, Philadelphia, Pa. 19105.
RECORDS MADE FROM YOUR TAPES. Also,
editing and mastering. Send for free brochure.
Nashville Record Productions, Inc., Dept. AM,
204 19th Ave., So., Nashville, Tennessee 37203.
COMMERCIAL SOUND SYSTEMS Sales and
service. For fast repairs contact Mr. Lawrence,
Erie TV & Sound. 215 -BA 3-3778, Philadelphia.
GIANT
BOOK SALE! Fine Readings. Free
catalog. Barton General Publishers Box 4487 -AD
Jacksonville, Florida 32201.
CIGARETTES (All Brands) $3.15 carton delivered,
postpaid, insured. Particulars $2.00. Coastal
Shipping Box 4487 -AU Jacksonville, Florida
32201.
CUSTOM STYLUS and cartridge re -tipping,
repairing. (Weathers, Ortofon, Edison, Shure,
etc.) Box 322A, Tuckahoe, N.Y. 10707, 914SP 9-1297.
CASSETTE REJUVENATION Those priceless
jammed cassettes can be repaired!! Send for
details. RAP Associates 81 Greenwood Road,
Andover, Mass. 01810.
TAPE RECORDER HEADS professionally recontoured and repolished. Savings up to 80% over
new replacement cost. Write for details. State
make and model recorder. P.O. Box 146, Goleta,
Cal.
93017.
Complete catalog!
6,000
STEREO
TAPES
Country
Folk
Rock
Jazz
Pop
Complete
Classical
and Western
new entertainment guide. A must for
every owner of an open reel, 8-track
cartridge, or cassette player/recorder.
Send 250 in coin, check, or money
order to Ampex, 2201 Lunt, Elk Grove
Village, III. 60007. ATTN: Dept. 115
AMPEX
STEREO TAPES
73
APRIL 1972
www.americanradiohistory.com
AmericanRadioHistory.Com
SITUATION WANTED
RADIO PROGRAMS
Serious young man looking for a job in the
Audio field, would prefer sound reinforcement or
studio recording job. Bob Miller, 246 Crestwood
Dr., Milltown, New Jersey 08850.
RADIO RERUNS, Complete broadcasts. 8C stamp
for free catalog. Box 724-A, Redmond, Wash.
BROWN UNIVERSITY SENIOR will graduate
in June seeks possible career in Audio recording engineering. Four years chief technician at
Brown University language lab, skilled in Audio Electronic basics. Willing to learn, travel etc.
Interested in a position with future, not necessarily electronics. Am political Science -Economics
major, fluent in three languages and plan to
acquire law degree. Write: Donald Stanford
Box 2342 Brown U. Providence, Rhode Is.
Reels high
02912.
98052.
OLD
RADIO PROGRAMS on Cassettes or
quality, low prices thousands of
your favorites live again, priced as low as
$8.00 for 6 hours. Catalog 50C. Remember
Radio Inc., Box 2513, Norman, Okla. 73069.
OLD RADIO PROGRAMS. Reels or cassettes.
Free catalog. Fred Berney, 5931 S.W. 8 Street,
Miami, Fla. 33144.
OLD RADIO PROGRAMS at low prices yet
large selection. Catalog 50C. The Best of
a
Radio, P.O. Box 1692, F.D.R. Sta., New York,
N.Y. 10022.
GOVERNMENT SURPLUS
JEEPS Typically From $53.90... Trucks From
$78.40... Boats, Typewriters, Knives, Airplanes,
Clothing, Multimeters, Oscilloscopes, Transceivers,
Photographic,
Electronics
Equipment.
Wide
Variety,
Condition
100,000 Bid
Bargains
Direct from Government Nationwide. Complete
Sales Directory and Surplus Categories Catalog
$ 1.00 (Deductible On Orders From Separate Included Catalog). Surplus Service, Box 820 -AUD,
Holland, Michigan 49423.
WAR OF THE WORLDS and other full length
old radio programs on LP records. RADIO,
Dept. AM; Box 844; Orange, Conn. 06477.
MOST AMAZING Radio Show ever produced.
Featuring Ken Nordine. On Cassettes. Free
Brochure.
"Incredible, But True!" Sawyer,
Michigan 49125.
OLD RADIO PROGRAMS. CATALOG $1.00
(refundable). The Radio Vault. Box 9032. Wyoming, Michigan. 49509.
EQUIPMENT WANTED
DO-IT-YOURSELF
PROFESSIONAL
ELECTRONICS PROJECTS$1.00 up. Catalog 25C. PARKS, Box 25665E,
Seattle, Wash. 98125.
The Worlds
Greatest
Speakers?
Every week some
manufacturer claims that
his speakers are the best.
Where then do Rogersound
Labs come in?
We make truly great
speakers like other people
do,only our bag is price.We
sell for 50% less because you
buy direct from the factory.
Columbia Records, Warner Bros., Reprise,
Vanguard and loads of other professionals
use RSL studio monitors.
For full information on how you can get
more speaker per dollar than you'd ever
dream could exist, write or call:
CASH FOR YOUR unwanted LP's and prerecorded tapes. Record House, Hillburn, New
York 10931.
WANTED: REK-O-KUT 150 or 240 Ipi lead screws for M -12S cutting lathe on a TR -43H
turntable. Eduardo L. Lozano, Urdiales 307-A,
Monterrey, N.L.-Mexico.
STELLAVOX SP7 RECORDERS, Accessories,
also Sennheiser MKH 405, MKH 404 microphones. Jerry Hyde, 301 Springdale Ave.,
Wintersville, Ohio 43952 Phone 614-264-4987.
WANTED-Mint condition
350 converted to
2
AMPEX 351-2 or
Track stereo w/or w/out
modifications. Reply to Box #AA2-1.
MANUAL, TEST REPORTS, MFR. literature on
rel precedent tuner. (212) RA -8-1935. evenings.
WANTED: One C-22 McIntosh preamp. Martin
Sullivan, 2722 South Sheridan, Philadelphia,
Pennsylvania 19148. 215-DE 4-3509.
TRAVEL RESORTS
MONT TREMBLANT LODGE Mont -Tremblant,
Que., Canada All Summer sports on the premises
including private 9 -hole golf course, 6 harthru
quick drying tennis courts, horseback riding and
water skiing. Ideal for family holidays and conventions. Tel. (819) 425-2711.
HEAR AND SEE the music of Greece and
Israel this year, for just $ 100 plus the lowest
TWA group rates. You can also soak up the
pleasures of Italy and Yugoslavia at the same
low rates. Contact SunnyLand Tours, 166 Main
Street, Hackensack, New Jersey 07601. 201-
487-2150.
TAPESPONDING
JOIN LIVE CLUB. Swap ideas. Use MAGIC
MAILERS. Sample. Miller, 10705-A Waterhole,
Tampa, Florida 33612.
Rogersound Laboratories
5706 Lankershim Boulevard
North Hollywood, California 91601
Phone: (213) 763-0855.877-1420
Advertising
Index
PLANS
&
KITS
INTEGRATED CIRCUIT KITS-Free Catalog.
FRAZER & ASSOCIATES, 3809 Surfwood Road,
Malibu, California 90265.
Check No. 74 on Reader Service Card
74
Allied Radio Shack
Ampex Corp
Ampex Stereo Tapes
Audio Dynamics Corp.
Audio Sales
BASF
BSR (USA), Ltd.
British Industries Corp.
David Clark
Downtown Audio
Dynaco, Inc.
Eastman Sound
Elpa Marketing Industries
Electro-Voice
Empire Scientific
Executive Discount
Shopping Service
Fairfax Industries, Inc
Finney Co.
Garrard turntables
73
18
68
31
65
3
67
70
8
63
35
28,39
9
41
43
64
3
Harman-Kardon
7
Heath Co.
14,15
Hi-Fi Newsletter
68
KLH Research & Development
17
Linear Design
60
Magazine Selection Network
69
Marantz Co.
Cover IV
Martin speakers
63
Matsushita Electric
33
Maximus Sound
23
Metrotec Industries
Cover III
McIntosh Laboratory
45
Newport Organs
58
Panasonic
33
Phase Linear
Pickering & Co.
Pioneer Electronics
Rectilinear Research Corp.
30
44
5
13
Rogersound Laboratories
.
Redwood Stereo
74
70
58
Russound/FMP
Sansui Electronics
19
57
Schwann Record & Tape Guide
H. H. Scott, Inc.
Cover II
Sennheiser
27
2
Sharpe Audio, Div. Scintrex
Shure Bros. Inc.
59
Sony Corp. of America
11
Sony/Superscope
45,65,67
Stanton Magnetics
21
73
Stereo Component Center
TEAC Corp. of America
1
Thorens turntables
35
Utah Electronics
34
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
64
29
OUR 25th YEAR
APRIL
1972
READER INQUIRY CARD
USE THIS FREE REPLY
CARD FOR:
More facts and Free Literature about the Products
described and advertised in
this issue. Check the appropriate box for immediate
results.
Please fill out name and
address information to get
product info, order merchandise, place a classified
ad or subscribe to Audio.
Audio Magazine APRIL 1972
This Card Expires JUNE 1972
CHECK BOX A or B beside each coupon number
to help me make an immediate decision to purchase.
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on the subiect up to date.
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48
63
78
93
108
123
19
34
49
64
79
94
109
124
5
20
35
50
80
95
110
125
6
21
36
51
65
66
81
96
111
126
7
22
37
52
67
82
97
112
127
8
23
38
53
68
83
98
113
128
9
24
39
54
69
84
99
114
129
10
25
40
55
70
100
115
130
11
26
41
56
71
85
86
101
116
131
12
27
42
57
72
87
102
117
132
13
28
43
58
73
103
118
133
14
29
44
59
r-74
88
89
104
119
134
30
45
60
75
90
105
120
A
B
A B
1
16
31
2
17
3
18
4
----
15
-
#
8
A
--_
-
A
--
_
AB
A
--------_____
B
135
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channel
sound.
Universal Decoder/Rear Channel Amplifier
Model SD4A-Q wired only, $149.95
Metrotec makes it easy!
Just add 2 speakers.
Universal matrix system decodes all the new SQ and EV 4 channel records
and FM broadcasts plus synthesizes quad sound from any 2 channel source.
Metrotec engineers have designed matrix/phase shift decoding circuits
which will decode all types of the new 4 channel records and
FM broadcasts. Just a flick of a switch gives the exact phase shifts and
coefficients to match the program material. Featured are ... a front
to back balance control which eliminates the need to adjust the volume
controls on separate amplifiers ... a master volume control
which adjusts the volume on all 4 channels simultaneously ...
tape monitor switch ... and a source selector switch. In addition to
precisely reproducing the 4 channels as they appear on the new
4 channel records, synthesized quad sound can be generated from any
2 channel source. This unique circuit separates the ambiance
information that would otherwise be lost and mixes it into the rear channels.
The Model SD4A-Q includes a powerful 30 watt rear channel
amplifier with all controls on a single panel. All you add are the two
rear speakers.
Most major record companies are producing 4 channel records.
Columbia, Project 3, and Ovation to mention a few already have
over 50 selections with many more on their way. 4 channel is here to stay.
Look into it.
The heart of the Metrotec 4 channel system is a new universal 4 channel
matrix/phase shift decoder. This amazing break thru in electronics
and recording allows 4 channels of information to be put on records,
tapes and FM broadcasting. No special turntables, cartridges or
FM tuners are required. The matrix decoder analyzes the information and
separates it into 4 separate channels. Recordings are made using
as many as 16 microphones. This allows for reproduction of all separate,
direct, indirect, complex phase and reflected acoustic signals.
The startling 4 channel sound is far more dramatic than anything you
have ever heard. The sense of special distribution adds a new and
important dimension to realism.
A great deal of this complex information already exists on many
stereo records. It goes undetected because the standard 2 speaker stereo
system cannot reproduce multi -dimensional signals. Your entire
2 channel collection has sound that you have never heard before. Try it.
The matrix coefficients have been designed and constructed in such
a way that they can be modified should changes be required at a
future date. This special care in engineering will make these products
valuable for many years.
Model SDW-Q wired $69.95
Model SDK-Q kit $54.95
If
your equipment consists of separate
preamp/basic combination, all you need
another basic amplifier and
a
is
Metrotec SDW-Q.
existing
receiver
c.
Metrotec SD4A-Q
Frequency Equalizer
Be sure to look into the Metrotec Stereo Frequency
Equalizer. Match the speakers to your room.
Guaranteed to improve any stereo system. You've got to
hear it to believe it.
Í¢Ì Metrotec Electronics, Inc.
33 Cain Drive, Plainview, N.Y. 11803 Telephone: (516) 293-2520
in Canada: GOULD MARKETING CO., LTD.
9429 Côte de Liesse Ro'.J Montréal 760, Que. (514) 636-0220 TELEX: 01-255 79
Check No. 56 on Reader Service Card
www.americanradiohistory.com
AmericanRadioHistory.Com
Utrot.,
Model FEW-1 wired $99.95
Model FEK-1 kit $79.95
Middle-of-the-road stereo people
are missing the fun of Marantz.
BLAH PEOPLE. Middle-of-the-road people who only listen
to the midrange because their power amplifier DISTORTS the
high and low frequencies. Because their 250 watt amplifier
is really only 250 watts right in the middle Because that's
where it's measured SMACK DAB IN THE MIDDLE! So when
the power drops off on either side they miss the BOOM, KA
BOOM of a bass and the crisp swissshh of the wire brushes.
Now take the Marantz amplifier Model
250. Marantz says it delivers 250 watts
RMS. That's 250 watts total RMS CON-
TINUOUS power. Over the whole
powerpushin' listening range. Right
through from 20 Hz to 20,000 Hz with
total harmonic and intermodulation
distortion at less than 0.1%! Fantastic!
Uncompromising music lover. Professional sound engineer. The Marantz 250 amplifier working in any system delivers continuous power at the critical EXTREME frequencies.
EXTREME right. EXTREME left. EXTREME high. EXTREME
low. Pure sounds. Total reality. Your kind cif stereo.
Priced at $495, the Marantz 250 professional power amplifier is only one of a brilliant line of components, receivers
and speakers from the makers of the world's
most expensive stereo equipment. Including a $149.95 console ampllifier.
Visit your Marantz dealer and listen
to our line. Marantz stereo at any price
is damn wr'I worth it.
immifzranf®
We sound better.
°Marantz Co., Inc., a subsidiary of Superscope, Inc., P.O. Box 99, Sun Valley, Calif. 91352. Ix Europe: Marantz Int'I S.A.-Flue du ChAtelain 40, Brussels, Belgium.
Ontario. Prices and models subject to change without notice. Send for free catalog.
Check No. 43 or Reader Service Card
www.americanradiohistory.com
AmericanRadioHistory.Com
In
Canada: Electrohome, Ltd., Kitchener.
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