december 1964 - American Radio History
DECEMBER 1964
60?
Recording the Muse on Tape
A Basic Course in Commercial
Sound
Electronic Organ Tone
Coloring
Low -Cost Volume Compressor
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AmericanRadioHistory.Com
TOUGHER HAN TUBES
l
New Scott Solid -State Amplifier Passes Rugged Torture Tests
Now you can own a powerful 80 watt solid state amplifier
constructed to standards unique in the high fidelity industry. The new Scott 260 uses rugged pre-tested heavyduty components, including massive heat sinks, heavy
printed circuit boards and new silicon output transistcrs.
Critical electrolytics are hand selected and have operating
capabilities far exceeding circuit requirements.
To insure the thoroughness of its quality control procedures, H. H. Scott called in transistor specialists with
many years experience in the design of critical military
components. Rugged tests were devised to subject the
amplifier to conditions far more severe than encountered
in normal use. These "torture tests" include: Applying a
"step -stress -test" to a selected sample of all components
used, simulating hundreds of hours of normal operating
life and showing up any components that might fail;
applying a unique "surge and cycle" test, normally performed only on rugged military equipment, to simulate
stresses the amplifier may be subjected to under the
most severe home conditions; elaborate pre-test and
checkout of all components, including transistors, to insure that components will not fail in service.
As a result of these extensive procedures, the 260
now combines the amazing virtues of transistors ... their
compactness, cool operating temperatures and fine sound
. with the ruggedness and reliability that the audiofan
has come to expect of finest Scott vacuum tube components. Backed by Scott's unique 2 -year guarantee, the
260 will give you countless hours of trouble -free fine
listening. Less than $260.
SPECIFICATIONS: Sine -wave power, 30 watts/channel; music power, 40 watts/channel
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Load impedances: 4, 8 or 16 ohms; full tape facilities including tape monitor and direct
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headset output (4) Master volume control (5) Separate bass
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Export Scott International,
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1965 CATALOG
FREESNEW
AND GUIDE
TO STEREO :
Scott, Inc. 111 Powdermill Road
Department 35-12, Maynard, Mass.
H. H.
D
Please send me your new 20 -page full -color
1965 Stereo Guide and complete catalog.
Send me complete information on new conby Scott
. component
quality in
beautiful, hand -finished cabinets.
e
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Name
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State
SCOTT'
Powdermill Road, Maynard, Mass. Canada: Atlas Radio Corp., 50 Wingoid Ave., Toronto. Cable HIFI. Price slightly nigher West of Rockies. Subject to change without notice.
Circle 100 on Reader Service Card
DEC., 1964
VOL. 48, No. 12
o
Successor to
,
Est. 1917
Number 16 in a series of discussions
by Electro -Voice engineers
C. G. MCPRouD Publisher
AUDIO
Editor
DAVID SASLAW
JANET M. DURGIN
DANIEL J. TOMCIK
Chief Engineer, Organs
Production Manager
Contributing Editors
HENRY A. SCHOBER
Business Manager
SANFORD L. CAHN
Advertising Director
EDGAR E. NEWMAN
Circulation Director
Representatives
Bill Pattie & Associates,
4761 West Touhy Ave.,
Lincolnwood 46, Ill.
James C. Galloway,
6535 Wilshire Blvd.,
EDWARD TATNALL CANBY
JOSEPH GIOVANELLI
HAROLD LAWRENCE
CHESTER SANTON
Los Angeles 48, Calif.
Warren Birkenhead, Inc.,
No. 25, 2-chome, Shiba Hama-
HERMAN BURSTEIN
BERTRAM STANLEIGH
matsu -oho,
Minato-ku, Tokyo, Japan
LARRY ZIDE
AUDIO
Articles
The RCA Victor "Dynagroove" SystemIn Two Parts-Part Two
A Basic Course in Commercial SoundChapter 9
Andrews
Arthur C. Matthews
D. Wolkov
S.
S.
44
Harry F. Olson
38
Norman Crowhurst
There is no mixing, adding of harmonics or overtones, or simulation of organ sound. The principle
involves the simple storage of the electromechanical equivalent of the original waveform itself, ready
to be released at the touch of a stop tab and key.
When these stored waveforms are compared visually
or naturally to the original, they appear identical
in all respects.
AUDIO Reviews
6
Light Listening
8
Jazz and All That
Record Revue 48
Bogen Solid State Receiver
Acoustic Research Speaker System
Weathers Stereo Turntable
50
51
51
There are a number of advantages, beyond the
purity of sound, to this system. It becomes possible
to provide an extensive choice of stops in a modest sized generator cabinet. And it also means an individual waveform source is used for every note of
every rank of the organ. All stops are additive, to
further duplicate the effect of a fine pipe organ.
Chester Santon
Bertram Stanleigh
Edward Tatnall Canby
AUDIO
Profiles
RT6000
AR-4
Townsend 82-2
The electro -mechanical system is inherently simple,
with no tuning required. There are no oscillator or
tone -shaping circuits to maintain, the only tubes
and transistors being in the power amplifier, a unit
of straight -forward high fidelity design.
AUDIO in General
Audioclinic
2
Letters
4
Audio ETC 10
About Music 14
Editor's Review 16
New Products 52
New Literature 54
HiFi in Germany-Corrections 61
Tape Guide 64
Inside Audio 65
Annual Index 76
Advertising Index 78
INSTITUTE OF
HIGH FIDELITY
INC.
Joseph Giovanelli
Edward Tatnall Canby
Harold Lawrence
Each note of every rank can be regulated for
transient sound character and volume so that each
relates musically to the overall effect. And finally,
ensemble effects are outstanding due to the additive nature of the design.
The unique nature of the Electro -Voice Series "D"
organs reflects the ingenuity of Dr. J. Dereux,
plus the careful application of modern mechanical
and electronic concepts by the Electro -Voice team.
Herman Burstein
Larry Zide
AUDIO (title registered U. S. Pat. Off.) is published monthly by Radio Magazines, Ine., Henry A. Schober, President; C. G. MCProud, Secretary. Executive
and Editorial Offices, 204 Front St., Mineola, N. Y. Subscription rates-U. S..
Possessions, Canada, and Mexico, $5.00 for one year, $9.00 for two years; all
other countries $6.00 per year. Single copies 60¢. Printed in U.S.A. st 10
McGovern Ave., Lancaster. Pa. All rights reserved. Entire contents copyrighted
1964 by Radio Magazines, Inc. Second Class postage paid at Lancaster, Pa.
For technical data on any E -V product, write:
ELECTRO -VOICE, INC., Dept. 1234A
Buchanan, Michigan 49107
.
a
o
RADIO MAGAZINES, INC., P. O. Box 629, MINEOLA, N. Y.
Postmaster: Send Form 3579 to AUDIO, P. O. Box 629, Mineola, N. Y.
AUDIO
the philosophy with which they are employed. The
Electro -Voice Series "D" organs defy such classification. They have no oscillators at all.
The E -V Series "D" organs produce their tones
from twelve synchronously driven rotor wheels, one
for each note of the scale. Each rotor serves to
electrostatically scan two stator plates on which
are engraved the exact complex waveforms that are
produced by organ pipes of outstanding timbre.
Low -Cost High -Performance Volume
Compressor 19
Recording the Muse on Tape 21
Electronic Organ Tone Coloring 25
Most "non -pipe" organs currently on the market
can be easily and neatly classified into types, based
on the type and number of oscillators used, and
DECEMBER, 1964
CuL41
..m._ -
s.....
5'kct Yoca
SETTING NEW STANDARDS IN SOUND
CIRCLE 103
1
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Coming
AUDIO CLINIC
Joseph Giovanelli
Send questions to
Construction
Matrixing Amplifier for
Two -Channel Stereo Signals. Wayne B. Denny. A
matrixing amplifier for altering the "stereo spread" of
two -track tapes recorded at
a performance of an amateur
group.
Sound Reinforcement
A Basic Course in Com-
Norman
Crowhurst. Chapter 10.
Final chapter of this series,
tying up all loose ends and
reviewing the previous chapmercial
Sound.
ters.
Two Engineered Temporary Sound Systems. David
S. Klepper. The Billy Graham Greater Boston Crusade required temporary
systems, both indoors and
out. Here's how it was done.
Profiles
JFD FM -Stereo Antenna,
Model LPL -10
JBL Stereo Control Center, Model SG520
Heathkit Solid-State AM FM -Stereo Tuner, Model
AJ43
In the January Issue
On the newsstands, at
your favorite audio
dealer's, or in your
own mailbox.
:
Joseph Giovanelli
2819 Newkirk Ave.
Brooklyn 26, N. Y.
Include stamped, self-addressed
envelope.
Overloaded
FM
Tuner
Q. I have a monophonic tuner of fairly
recent origin and a monophonic amplifier. My antenna consists of two folded
dipoles at right angles to each other, connected in parallel and located in the attic
of my one-story house.
Within a radius of five miles are the
transmitters of at least two TV stations
and three or four other AM and FM stations, I hare no interest in hearing most
of them.
My problem is that on several points
on the dial I receive two stations simultaneously, and at leas, two points I receive three, usually with considerable distortion and odd noises. WASH -FM is
the chief offender. It is located less than
a mile away from me. It happens that
one of the stations I would like to receive is WBAL-FM Baltimore, about 40
miles away, but at that location on the
dial all I can get is WASH, with an admixture of some other station I cannot
identify.
I might mention that a line to Baltimore on the map would pass approximately through the WASH transmitter
tower.
In the past year, the tuner has been
aligned three times, the last time by the
manufacturer who replaced a tube or two
and installed some new front-end stuff
to bring up the tuner's performance to
the level of their current models. Their
treatment has improved matters-I used
to get WRFL, Winchester, Va. instead of
interstation noise over the band from 100
mc down to 88 mc, WGMS used to interfere at more places than it does now,
and I used to get three stations at a time
at more places than I do now, but whereas I used to get WITH -FM Baltimore
when the tuner was new, now I can't get
it at all, and whereas before I was able
to get WBAL faintly and with distortion,
along with a lot of WASH, I cannot find
it at all any more.
Until 6 months or so ago, I accepted
2
the nonsclertielly and failure to reject
these local signals as unavoidable. (I remember one of the claimed advantages
of FM over AM as it was trumpeted
some years ago was that FM had made
it impossible for the FM tuner to pick
up more than one station at a time.
That's beside the point.) Aware as I was
of the proximity of powerful transmitters which make hash of AM reception
here, I more or less lived with the situation. Then I talked with a neighbor,
telling him of my troubles. He was much
surprised, and told me that his old -model
FM tuner at his home a few blocks from
the TVASH transmitter, had no trouble
(with a pair of rabbit ears) in picking
up WBAL.
TVhat should I do? Stanley Metalits,
Kensington, Maryland.
A. As time goes on, tuners have improved remarkably in sensitivity to weak
signals. This is not without price however. The more sensitive a front end becomes, the more susceptible it becomes
to overloading in the vicinity of strong
signals. Once the front end is overloaded,
all the rules about capture ratio go out
the window because the signal feeding the
detector is a composite.
To explain this better, assume that a
weak signal is passing into the front end
of your tuner. It will get into the i. f.'s
in the customary manner but because the
front end is saturated with the strong
signals around it, there is a mixing process taking place in the front end which
results in the output being made up of
not one signal but a combination. The
signal passing into the i.f. amplifier is
made up of the weak signal, influenced in
character by a signal possibly half the
dial scale away. The i.f. amplifier and
detector circuit do not know this; they
are fooled into thinking that there is just
one signal.
This is not all that takes place when
two signals on the same or adjacent channels are passed into the detector, assuming no front-end overload. To make this
simple, two signals still have separate
identities, and the stronger one will be
separated out by the detector and presented to the audio stage free from interference. The full story of capture ratio
is, unfortunately, too detailed to go into
in this context.
Probably the reason your tuner works
(Continued on page 66)
AUDIO
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AmericanRadioHistory.Com
DECEMBER, 1964
To activate the cueing
feature (at the start of a
record, or during play),
simply press manual tab.
The tone arm rises...
stays suspended a safe
half inch over the record. Leave it where it is,
or position it over any
other groove desired.
Now, press the cueing
control. The arm lowers
slowly and accurately.
LAB 80-599.50
Integral tone arm cueing
is featured in Garrard's
new Lab 80, the first Automatic
Transcription Turntable!
Here's how it works:
single record: Press the manual
tab. This starts the motor and activates
the cueing feature. Then, position the
To play a
tone arm above the first (or any)
groove. The arm is suspended a safe
half inch above the record. Now, press
the cueing control and the stylus lowers
slowly into the groove.
To cue a
To pause during manual or
automatic play:
Press the manual tab. The arm rises
directly over the record groove. The
turntable continues to revolve. When
you are ready, press the cueing control.
The stylus descends safely. The music
continues from where you left off.
handling increased. Now, in the Lab
80, Garrard has incorporated the convenience and safety of this ingenious
cueing control ... built into an automatic unit for the first time. This, and
other advanced features of the Lab 80
are explained in Garrard's new 32 page
Comparator Guide covering the entire
line. For a complimentary copy, write
Dept. GX-14 Port Washington, N.Y.
®
record during manual or automatic
Press the manual tab. The arm
rises and suspends a half inch over the
record. Move the arm to the band or
play:
groove desired, and press the cueing
control. The stylus lowers gently into
the groove.
As tracking forces have become lighter,
and stylus assemblies more delicate, so
has the danger of damage from manual
Circle 104 on Reader Service Card
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AmericanRadioHistory.Com
IF01,'I,U'S
I'L.vFT
LETTERS
Stereo Enhancement-Channel A
SIR:
I
was surprised to read Mr. Canby's arti-
rather
heartily endorses that strange process called
cle in the October issue in which he
A studio control room where the
rogrammcs are passed tirough
QUAD cor trol uni lor special balancing.
BRITISH
BROADCASTING
Quality Check Room. Programmes
originating from abroad are here
passed through a QUAD control unit
and power amplifier where they are
filtered and balanced for optimum
quality prior to transmission.
In
Britain and many leading
European countries several thousands of QUAD products help to
provide the best in broadcasting
and recording. This same equipment is used in many more
thousands of homes where people
listen to music.
Ask for full details of the QUAD range.
"stereo enhancement." This process purports to revitalize a mono recording so that
it offers "improved" sound when played
on stereo systems.
The author makes several statements
that would not seem to bear up under close
scrutiny. While it is true that identical
signals in each speaker may seem to emanate from a point midway between them,
this is true only when one is listening from
a point equidistant from both speakers. In
his article, Mr. Canby implies that all listening is done from this mid -point. Actually, this is rarely the case. Most people
are closer to one speaker than the other
in many situations. Thus, that "squashed -up
sound" he refers to is not always present.
He also says that the layout of the classical orchestra can almost be heard on the
enhanced recording (violins on the left, the
bass to the right). But what about the poor
brass and woodwinds that are often seated
in the center? What about the unearthly
sound of the human voice whose high tones
are heard in one speaker while the fundamentals are coming from the other, 8 -ft.
away ?
Finally, the question arises as to what is
more natural, the spread of sound, or its
balance and unity upon reaching the ear?
Often, the enhanced recordings make the
speakers sound out of phase. And show me
the mature listener who would prefer the
disembodied sound of out -of-phase music
merely to achieve some sort of unnatural
spread! Perhaps in our preoccupation with
this newest advance in audio (and I refer
to real stereo, not "enhancement") we fail
to hear the music through the "spread."
ANASTASIO A. ROSSI
Coordinator of Music
Mount Pleasant Central School
District #1
Thornwood, New York
Off the air monitoring. QUAD tuners
provide a continuous check on trans-
mission.
Stereo Enhancement-Channel
B
SIR:
In answer to Mr. Rossi, I would say first
that the "bunched up" sound is not to be
for the closest approach
to the
The Quality Monitor room. QUAD
used for a final check on the overall
qual ty of British Broadcasting.
original sound
Photographs by kind co-operation of the British Broadcasting Corporation
...
and in
your own
home, too,
THE ACOUSTICAL
QUAD for
the closest
approach
MANUFACTURING
to the
CO. LTD.
original
sound.
Huntingdon, England.
got rid of so easily-it follows you wherever you may sit. Makes no difference at
all; the bunching merely moves from side
to side as you do (or as you turn your balance control). For my ear it is unpleasant
in any position it may seem to take.
Further, I think he is making an old
semantic mistake, the all-or -nothing. His
criticisms of "enhanced" sound are real;
there are genuine dangers. But like so many
artistic matters, this one involves a balance
between desirables and undesirables and,
more important, it invites ingenuity of a
constructive, inventive sort. The question
isn't "Is `enhancement' (all) good or (all)
bad" but "what can we learn to do with this
potentially useful new technique?"
Finally, Mr. Rossi in his last paragraph
almost makes the mistake I avoided, the
comparison between real stereo and "enhancement." It isn't a substitute for stereo,
this process, but a substitute for mono.
What is important, I think, is to see what
is being done by those who are experimenting with it. Not what ought or ought not to
be done.
E. T. CANBY
AUDIO
4
DECEMBER, 1964
Circle 112 on Reader Service Card
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AmericanRadioHistory.Com
"HIGH FIDELITY"
PERFORMANCE
FROM AN AUTOMOBILE?
As a dyed-in-the-wool audiofan, you
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"NETWORK" SPARK-INJECTORTM
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Anyone accustomed to hooking up
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it in 10 minutes-the layman in 20.
MORE POWER AT HIGH SPEEDS
In a standard ignition system, spark
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time the breaker points are closed,
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and decreased power availability.
Spark -Injector gives much greater
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GUARANTEED INCREASE IN SPARK ENERGY
125%
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25%
1000
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ENGINE SPEED, RPM
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Note that at 4000 rpm you get a
110% increase in spark over that
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BETTER GAS MILEAGE
Increased spark energy ensures
burning up every last drop of the gas
mixture in your cylinders. Spark Injector users report an average of
12% increase in gas mileage-some
over 20%. With standard ignition
systems, gas mileage deteriorates as
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-Injector you will get greater Spark
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PERMANENT TUNE-UP
Points and condenser have an expected life of 75,000 miles with
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Works with any auto or marine engine using battery ignition, 6 or 12
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Chester Santon
Disc and tape reviewers are not immune to impressions of recorded sound
when they visit a major annual High
Fidelity Show. The 1964 New York event
left me with a few thoughts pertinent
enough to be included in this month's
column. As the man who sets up my
`}
00
LIGHT LISTENING
-- -- -
AM4
copy in type will recall, I was somewhat
taken with the cleancut job done on records by transistor amplifiers and preamplifiers at the 1963 Hi Fi Show. Possibly because of exposure to equipment
then limited pretty much to the top price
range, I came away from the '63 event
with a very favorable impression of solid-
state gear. After listening to records and
tapes at the '64 show on transitsor
equipment offered in a wider range of
prices, I was struck by a certain sameness in the sound. So much of the recorded material had a similarity in the
basic nature of its sound, I'm beginning
to wonder if transistor gear subtracts
some of the characteristic, color -producing quirks of musical instruments in attaining its undeniably clean sound. The
question, for all its subjective nature,
would be easier to answer if the recording industry could provide us with
stereo discs whose average in audio quality is more in keeping with the specs
already attained by solid-state equipment. As matters stand now, I spend
part of my listening time still wondering
why some records, even on major labels,
make my top-notch tube equipment
sound only a trifle better in frequency
range than my neighbor's five year old
console.
Alec Guinness in Dylan (Original Broad-
way Cast)
Columbia Stereo Tape DOQ 666
Columbia Records has joined the other companies in offering the spoken word on 4 -track
stereo tape at 3% IPS. The slower speed is
no longer a novelty on commercial releases.
London Records established 3% as a perfectly
legitimate medium for dramatic presentations
on its lengthy series of Shakespeare plays recorded by the Marlowe Dramatic Society. As
my listening time has permitted-a good part
of an evening can he spent with one of these
reels-I've been sampling some of the Shakespeare tapes at 3%, finding them more than
suitable for true reproduction of the human
voice in a wide range of stage emotions. Since
no stretch of the imagination can quite put a
group of Shakespeare plays in the light listening category, I haven't reviewed any drama
on 3% until this appearance of Columbia's
recording of "Dylan," starring the great Alec
Guiuess in the role of the roistering Welsh
poet. It's heartening to discover that more
than one label can get very good results on
speech in commercial releases at 3%. It
hasn't been too difficult to demonstrate acceptable frequency response at tape speeds of
3% and less at press showings of systems
carried over from the lab on a soft pillow.
Making 3% work under random sampling of
an assembly line's output has been something
else again.
Heard with only one interruption in the
tape version, the twenty scenes of the Sidney
Michaels' play take on their natural momentum as Guinness creates a Dylan Thomas
a bit more convincing to the ear than his
stage makeup was to the eye. Stereo effects
throughout the play are just as realistic as
any I've heard on 7t/2 tapes. Columbia's listing of the reel's playing time is somewhat
confusing. The box claims three and one half
hours playing time for this new series of
plays recorded at 3% IPS. This is true
enough in the case of a companion tape release of Richard Burton's "Hamlet." Once the
"Dylan" tape box is opened, the folder inside
lists the reel at the more accurate figure of
two and a half hours. With a price tag no
higher than that of the LP album counterparts, Columbia's tape release of "Dylan,"
"Hamlet" and "Who's Afraid of Virginia
Woolf?" represents a darn good buy for
llroadw ay -minded tape fans.
Let's Ring
Tree
Bells
Around the Christmas
RCA Victor
LSP
2914
RCA has again called upon carillon virtuoso, John Klein, in planning an unusual Yuletide release. Here he performs on location at
the console of what is claimed to be the
world's largest modern carillon installed at
the Coca-Cola pavilion at the New York
World's Fair. The instrument is an electromechanical device built by Schulmerich, Inc.,
of Sellersville, Penn. This latest creation, similar to carillons built by the firm for the 1958
World's Fair in Brussels and the 1962 Seattle
World's Fair has a total of 610 bells. The
bronze bells, tiny in size when related to those
used in conventional carillons, produce tones
barely audible to the human ear. Modern high
fidelity equipment amplifies the sound and, in
the case of the Coca-Cola installation. feeds
it to an array of fifty-seven directional loudspeakers mounted on the 120 -foot tower. Approximately 3,000 watts of audio power tire
brought into play when the system is operated in the mode that spreads sounds to
the entire backgrounds. In producing this
album, RCA Victor recorded the Henri Rene
orchestra and chorus at Webster Hall in Manhattan before taking the tape to Flushing
Meadow where Klein added the sound of
bells to a collection of traditional carols and
Christmas songs. The blend, handled with
great fitness by engineer Ed Begley, makes the
carillon a natural member of a rich -sounding
cast.
Garbo
M -G -M E 4201 P
Every now and then a recording comes
along to remind us how much a voice can convey within a limited frequency range. Here is
a succession of scenes from famous MGM motion pictures starring the immortal Greta
Garbo. During the decade when these films
were made-1930 to 1939-sound recording
was still a bit of a novelty at Hollywood
studios. For that matter, a few men now
prominent in the high fidelity industry were
probably still attending high school. When
Garbo made her first appearance in a talking
picture (Anna Christie in 1930) MGM's sound
technicians had to content themselves with a
frequency response that sounds pretty primitive by today's LP standards. Yet the essence
of Garbo as most of us remember her comes
through in the nine different sound tracks
selected for this recording. If you haven't seen
any of her films in their recent revivals, listening to this record can be an uncanny experience. Far more than any photograph, the
sound of Garbo pronouncing a given word in
her unique way can throw one right back into
the Thirties. A heartening by-product of this
collection of scenes is the realization that we
no longer have to endure the fancy scenarios
and stilted leading men that once were commonplace in the movies.
CIRCLE 107
6
AUDIO
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DECEMBER, 1964
Before multiplex came along,
you could get by
with an average tuner.
Now you need a Fisher.
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The seven stereo tuners currently made
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In the good old days of strictly monophonic FM, any reasonably well -engineered tuner brought in at least your local
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a Fisher tuner still made quite a difference
in sound quality; but it was a difference in
degree, not in kind. Multiplex has changed
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Even though FM -stereo has potentially
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AUDIO
7
DECEMBER, 1964
www.americanradiohistory.com
AmericanRadioHistory.Com
how good
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In March, 1940 Woody Guthrie made
a series of more than 30 discs for the
Library of Congress. The recordings,
made at the Department of the Interior
recording studio in Washington on an
old Presto disc recorder, consist of an
interview between Woody and Alan
Lomax, interspersed with a substantial
number of folk songs. It was originally
thought that these discs would be the
basis for a radio program, but the plan
was never realized, and the discs remained in the Library's archives for nearly a
quarter of a century. Now, thanks to
Elektra Records, these recordings have
become available to the public on three
long-playing discs. The process from the
original recordings to the finished LP's
was a long one involving months of
painstaking effort.
After surmounting a number of legal
obstacles, work began in Washington,
where Robert B. Carneal, chief engineer
at the Library of Congress recording
laboratory transferred the original disc
recordings to 15 ips tape. Recorded at
331/3 rpm on 12 -in. acetates at 110 lines
per inch, they had about eight minutes
on each side and had been cut up to a
3 -in. center diameter. The original lacquers had been stored in old Metal containers, and they were scratched, dusty
and had been played a number of times
with the kind of playback equipment that
was generally available in 1940. Several
different types of blank discs had been
used in cutting the original records, and
consequently there was a difference in
thickness that resulted in varying groove
depth and width. Before transcribing
each disc, it was carefully washed, and
Carneal checked the groove dimensions
with a binocular microscope. From his
collection of more than a hundred different playback styli, he was able to select the one that matched each groove
contour most closely, and the sound was
rebalanced in transfer, utilizing a Klein
& Hummel EQ 1000 equalizer.
Fig. 2. Woody Guthrie.
In New York, a 7?2 ips copy was made
of the tape transfer, and work began on
putting three days of recording into
shape as a three-hour commercial recording. Many of the songs had been re (Continued on page 74)
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Fig. 1. Jac Holzman (left) and Sid Feldmen cutting the
LP
masters for the Woody
Guthrie/Library of Congress Recordings.
AUDIO
8
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DECEMBER, 1964
Can you recognize these three great stars?
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9
DECEMBER, 1964
www.americanradiohistory.com
AmericanRadioHistory.Com
show must have added up to quite a sizeable plot, maybe a quarter acre.
My favorite memory, though, was the
Most Significant Booth of All, occupied
by that excellent maker of high quality
throughput equipment (amplifiers, pre amps, et al)-McIntosh. On the day I
visited McIntosh, at least, there was no
reproduced sound at all in his exhibit.
Not a trace. Was I impressed, especially
AUDIO FTC.
Edward Tatnall Canby
since the place was absolutely jammed
THE BIG SHOW
1.
Velvety, Soothing, Relaxing
Maybe it'll seem late and after -the -fact
to comment at this stage upon the autumn hi fi shows when winter is already
hard upon us. But deadlines being facts
of life, it must be (it always has been)
now or never. The fall merchandise, after
all, was labeled "1965" and there are still
a few weeks to go until that halcyon time
arrives. So herewith my late '64 comments.
My show, of course, was the New York
International High Fidelity Music Show,
if I remember the fancy title correctly.
Others weren't very different, I expect.
As for this New York show for 1964-er,
1965-I really enjoyed every moment of
it. Was I surprised.
Much as we love our hi fi and the very
idea of componentry and home musicry
(to invent a ghastly term), many of us
reporters do privately groan each year
in anticipation of the big annual noise
makers. Yet we're always there, you may
be sure, because we can't afford not to.
The shows are too important for us. The
public may learn a great deal-we learn
much more. We see Everybody who is
Anybody in the flesh, of course, which is
worthwhile. And we see every product
that Anybody of Any Importance is
making or about to launch, which is even
more important. If not in the flesh, then
in metal, glass and plastic. And last but
NOT least, we hear. We hear just about
everything, or the output of everythingthe throughput, if you wish-in terms of
of loudspeaker and earphone sound.
We hear with unusual of eency, too;
for as everybody knows, there are seldom
less than three audible signals available
to the ears at any geographic point in a
hi fi show and sometimes five or six. To
adjust relative volume, one need merely
walk a few feet one way or the other.
Easy.
Yes, even so, I did enjoy this year's
show. Perhaps it was the hoped -for result
of my personal audio drought, my "sabbatical" of the previous months; it was
a kind of coming -back party for me. But
I think there was more to it than that.
What struck me-and I'm not yet going
deaf-was that the big show wasn't noisy.
Definitely, the noise level was not only
more circumspect in the large average
this year; it was better controlled, better
channelled into usefulness, with better
"separation" than I ever remember from
previous year's. So it was in New York,
anyhow.
Am I dreaming? I don't think so!
Very seldom, this year, did I hear that
familiar horrid, hollow, bumping and
thumping that betokened a mammoth
loudspeaker on the loose, through the
wall in the next booth. Last year, many
a good exhibit was ruined for me, as for
others, by that sort of dog-eat-dog competition. Maybe the knife twisted both
ways last year-anyhow, it was good to
feel this year that mutual respect had
somehow managed to rise a bit and/or
big noise no longer seemed to be the selling point it once was. More power to you,
gents-I mean less power.. .
The result of this unaccustomed kindness toward us dumb animals was, as I
sensed it, that a great many more listening rooms presented a good case for their
enclosed products. A large number of
exhibitors were able to run remarkably
quiet demonstrations without hopeless
interference, their volume levels down to
a pleasurable conversational range. (Perhaps this was significant-in ye olde hi
fi days constructive conversations in most
show rooms were impossible. No salecouldn't hear yourself think.) People
came in and made relatively unhurried
evaluations of what they saw and heard;
they talked, to each other and to the
people in attendance. They could even
sit down-another good sign. A lot of
the booths featured comfy chairs and
they were always full.
The still -lively interest in earphone
listening lent a novel touch to all this
relative quiet. (Relative, mind you. I
wouldn't have called it exactly the silence
of the tomb.) Imagine walking into a
display to find dozens of people, earphones on heads, lost in silence, living
in a private shared world of their own :
simultaneous smiles, frowns, beat-tapping-and the newly entered person
(me, for instance) could scarcely wait
out of curiosity to hear what they were
all smiling, or frowning about.
That was one area where signal interference was absolutely at zero. Collectively, the intra -earphone territory at the
with people. Must prove something or
other. Was it the all -visual appeal of the
lovely McIntosh instruments/ Or that
velvety, soothing, relaxing SILENCE?
2. The Sound-Alikes
What was Most Significant at the fall
fi show-other than the improved signal-to-noise factor?
Well, I'll skip transistors because everybody knows they're significant and
getting better and better, etc etc. The
thing that struck me above all else (even
above the astonishing number of home
tape recorders in evidence) was simply
the sound of a thousand loudspeakers.
For this year the sound was not only less
loud but also significantly DIFFERENT.
hi
It
was the year of the sound-alikes.
In fact, I've just invented a new club,
the Sound -Alike Club, for speaker manufacturers, and I've appointed a whole
slew of charter members, whose names
are strictly restricted to my own private
thoughts. A lot of the sound -alike speakers were brand new; but they joined a
growing coterie of loudspeakers already
familiar to us, to make an increasingly
large and unmistakeably important element in the listening spectrum-at the
hi fi show and in a million dealers' show
rooms too.
An old thesis of mine, as you'll remember, is the platitude that if all loudspeakers were 100 per cent hi fi they
would all sound exactly alike. For we do
have an ideal, after all, however unattainable in practice; and that ideal allows for no tolerance whatsoever in the
faithful reproduction of hopefully idealistic sound.
In practice, we live with a great deal
of tolerance, complicated by factors of
taste and preference which are important
to all of us. Nevertheless, we all continue
to huff and puff, year by year, in our
gradual approach to that ever -shining
ideal of absolute fi, in our speakers as in
other elements of the whole hi fi kit and
caboodle.
And so the new and larger group of
sound -alike speakers, of every shape and
size, in every price range imaginable,
tended to bear out my thoughts of last
year that there was a strong chance
speaker sound would be getting better
pretty soon. It is getting better, in all
areas, top to bottom. That is, it's getting
more uniform.
AUDIO
10
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AmericanRadioHistory.Com
DECEMBER, 1964
If you th et
you ea t
the best high fidelity co
check
nents available, bar o
ree independent
these three
azine surve s
They agree on tneïa° choices
the test turntable and the lesi
loudspeakers - moderately
priced
fama
Popular
Science (Sept. 1963)
1y449
hi-h/tápe
rnIg
(Fall 1963)
(1964)
TURNTABLE
LOUDSPEAKERS
AR two -speed
AR -3's
two -speed
AR -3's
AR
AR two -speed
AR -3's
The AR turntable-less
than IL2 the cost of other
arm -turntable systems
over which it was chosen.
AR -3 loudi peakcrs-less
than 1/3 the cost of other
speakers over which they
were chosen.
*The Bravo survey introduced its selection of top components with: "If music is so deeply your passion that it makes you intolerant of
all compromise...you may enter that rarified area of audio where nothing matters but the dedicated pursuit of perfection."
The Popular Science panel tried to eliminate frills, and limited its choice to compact speakers for reasons of practicality in the home,
but stated: "Where there was a more expensive component that produced a detectable improvement in sound, it was chosen."
The Hi-Fi/Tape Systems survey referred to its choices as "the least expensive way to obtain state-of-the-art performance."
The Popular Science survey also recommended Roy Allison's High Fidelity Systems -A User's Guide
(AR Library Vol. 1, $1). This book may be purchased at many AR dealers', or you may order it directly with
the coupon below.
ACOUSTIC RESEARCH, INC., 24 Thorndike Street, Cambridge, Massachusetts
02141
Please send me Allison's High Fidelity Systems-A User's Guide. I enclose $1 in cash or check only, and /or
Please send me free literature on AR products, plus the complete lists of components chosen by each magazine.
Name
Address
Circle 106 on Reader Service Card
AUDIO
DECEMBER, 1964
J
11
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AmericanRadioHistory.Com
Gray Flannel Sound
What I heard as a fact at the show
was what I had anticipated in theory in
my earlier article. This year there is
clearly a sharp difference between the
two major groups of loudspeakers, and
it is an ear -difference. One group is the
sound-alikes, a growing number of speakers that tend in major respects to sound
more or less alike in over-all sound quality, without sharply noticeable differences from one to the next. They are
neutral, as related to each other. The
bigger, fancier ones have splendid specs
in detail-wide spectrum, ultra -clear high
highs, smooth middles, crisp lows; the
cheap items may lack a lot in the top
and boast very little low bass at all, but
the over-all principle holds : in spite of
these differences, these speakers do sound
alike, and strikingly alike, for the instant
ear. This is a value judgment that is too
quick for fancy analysis; it hits you
automatically, without effort on your
part; it is good for any ear and especially the ears of the inquiring neophyte,
the awaited customer.
In contrast, the other group of speakers are non -conformist. Unlike the colorless, conformist, neutral -minded soundalikes, as much resembling each other as
so many gray flannel suits on Madison
Avenue, these strong individualist speakers are daily becoming more noticeably
"different", more consciously special for
the average ear. The sound-alikes blend
into a colorless nonentity wherever you
hear them. You forget the speakers and
listen only to the program material emanating from them, which they pass slavishly on to you, without comment, un-
...my Norelco '401' has proved itself
as a
thoroughly professional recording instrument,"
says popular FM broadcaster, Skip Weshner
"No matter where make them, my tapes have to meet the broadcast
standards of the leading FM stations around the country. My Norelco
'401' gives me tapes that not only meet or exceed these standards, but
on playback on the '401' I defy any listener to tell the difference between
my live broadcasts and my taped ones!
"As to reliability, my Norelco has been on the firing line in all locations,
five nights a week, month after month, year after year; yet has required
less maintenance than any other recorder I've ever used.
"Although the '401' was designed for the operating convenience and
for the pocketbook of the home owner, in my book it's as good as having
an entire recording studio in a suitcase!"
I
The Norelco Continental '401' 100% transistorized 4-track stereo/ mono, record/
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Fidelity Products Division, 100 East
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Noreko
changed.
The individualist speakers are rugged
individuals of the old school; they tend
not to sound alike. And that, admittedly,
has long been their strongest virtue.
Each has its own distinguishing character, its own sound color, its own type
of presence, its special enchanced bass,
lively treble or golden mid -range. Strongminded speakers! From one maker to the
next, often from model to model within
a given line, these rugged speakers show
differences that in the continual AB
comparisons at a hi fi show are quite
startling, from one booth to the next.
I noticed them, you may be sure. So
did a lot of other show visitors, you may
also be sure. Simply because they sound
so unlike the sound-alikes with their conformist neutrality, utterly colorless, servile, undramatic.
You see, we are in a period of change,
here as in the great areas of our national
life. It is no longer an age of rugged
individualism. This is the new age of conformity. I sometimes feel like shedding
a tear for the distinguished old-line
speakers of yore, and their heirs of today, because after all, I'm a non -con (Continued on page 57)
CIRCLE 113
AUDIO
12
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AmericanRadioHistory.Com
DECEMBER, 1964
o
TYPE
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Low cost is only part of the story.
Additional benefits-as in all RCA germanium audio transistors-include exceptional uniformity,
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www.americanradiohistory.com
AmericanRadioHistory.Com
elk
N.J.
The Most Trusted Name
in Electronics
From my seat a few inches from the
cello section, nearly every movement of
the conductor could be seen. During the
ABOUT MUSIC
Harold Lawrence
j
How To Sit Four Feet From A Symphony
Orchestra And Like It.
-
of the
United Nations is not designed for
music. Its absorptive surfaces soak
up sound like a giant acoustical blotter, to make speech intelligible over the
public address system and through the
headphones for simultaneous translation located near each seat. At symphonic programs, some listeners are reminded of the dry acoustics of N.B.C.'s
Studio 8-H. An orchestral player
summed up his reaction to the General
Assembly Hall: "It's like having six
blankets thrown over my instrument."
Nevertheless a concert at the U.N. is
usually a gala affair, not to be dampened by the hall's acoustical shortcomings.
Such an event took place on October
24th ,when the London Symphony Orchestra capped a brilliantly successful
week of appearances in New York with
a concert in celebration of United Nations Day. By the time we arrived at
the Hall only a few seats in the first
row were vacant and we found ourselves
on the right, looking down the f -hole
of the third cello. The player greeted
me and shook his head in mock solicitation : "Too bad about your seat.
THE GENERAL ASSEMBLY HALL
. Would you like me to play on one
hair of my bow to cut down on the
buzzing 7" I turned down his offer; it
wouldn't have helped anyway. For the
rest of the afternoon I was to hear all
the cellos with startling, if unwanted,
clarity.
George Solti now strode into the hall,
hopped onto the podium, bowed smartly,
and turned to the players, who covered
every plank of the stage. The position
of my seat allowed me to observe Solti
as he faced the musicians. With a conductor whose translation of musical
rhythm into corporeal rhythm is always
vivid and dynamic, the concert promised
to be a good one, visually if not acoustically. And the visual element was
enhanced by the fact that the lights remained at full strength due to the presence of television cameras.
There is a great deal to be said for
this kind of ringside listening, both for
the layman and the musician. True, the
balance is impossible: instruments are
either too close or too distant, and there
is never any sense of a homogeneous ensemble at work. But the effect of such
close proximity can transform the spectator into a participant.
-
Hg.
1.
George
Solti conducting.
14
Bruch Concerto, violinist Isaac Stern
had reached a climactic phrase which
was to be accompanied by pizzicato
cellos. The attack of the first pizzicato
notes was not precise enough for Solti.
Instantly he turned to the cellos and,
with raised eyebrows, beat time as if
each beat were the snap of a whip;
the ensemble straightened out at once.
It was as if we in the audience had been
flashed the signal.
Under these circumstances it was easy
to identify with the cello section. But
the sense of involvement extended to the
soloist as well. Solti had just launched
into a vigorous tutti when Stern, his
back to the audience, playfully beat
time aloud for the conductor: "One .. .
two
three
four." Solti endured
it for a few bars, then broke into a wide
grin at the kibitzing. At another point,
Stern missed a high note in his cadenza;
the two men exchanged a quick glance,
and Stern winked at Solti.
Elsewhere, soloist and conductor
seemed to forget themselves in the score;
and when Solti was not blocking Stern
from view, their profiles were juxtaposed
in ways that a cameraman couldn't have
planned better-Stern's robust face,
slightly reddening in the heat of a key
phrase; and Solti's agile features and
hunched athlete's shoulders darting hack
and forth. Unfortunately, none of the
many cameras focused on the performers from the booths above the stage were
in line for such a shot.
For the rest of the program, Solti
and the orchestra held the spotlight in
Bartòk's Concerto for Orchestra, and we
were given the opportunity to study this
conductor's podium technique at close
hand. "The gesture," wrote the late conductor, Nicolai Malko, "is the fundamental element of the conductor's technique just as touch is to the pianist."
In the world of conducting, podium
choreography has ranged from the style
of Fritz Reiner, who cultivated a dry
vocabulary of tight, precise movements,
to the celebrated exuberance of Leonard
Bernstein. Solti belongs to the expressive school, far from the vest-pocket
approach or the one-armed manner advocated by Richard Strauss, who asserted that the left hand should be left
in the pants pocket. The Hungarian born conductor uses not only both arms,
but his entire body in directing the orchestra. His directions range from the
tiniest movements to those of a calisthenics instructor.
Solti seems capable of producing the
slightest dynamic gradation with almost imperceptible gestures. In the first
movement, the entrance of the three
trumpets in bar 39 was too soft. Solti
(Continued on page 70)
...
AUDIO
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...
DECEMBER, 1964
...THE FINEST
LOW -POWERED
AMPLIFIER ON THE MARKET..."
the Dynakit SCA-35 gives
superlative performance at less than $100
$99.95 kit
$139.95 assembled
Now there's a Dynakit for everyone. Long acknowledged as the
quality leader of the high fidelity industry, with performance di-
rectly comparable to the most extravagant designs, Dynakit now
introduces high quality performance concepts at a remarkably
low price. Take the time to listen to this latest Dynakit on your
favorite speakers. Compare it to amplifiers at least twice its
cost. Even with low efficiency speakers, the SCA-35 sounds like
Why does the SCA-35
a big, powerful, expensive amplifier.
sound so much better than higher priced designs? As detailed
and as fine as its specifications are, they cannot adequately define absolute performance. Dyna's painstaking engineering and
consummate concern with quality have evolved unique circuitry
which fully utilizes the superior performance characteristics of
patented Dynaco output transformers-transformers frequently
used in far more expensive equipment than our own. Years of
refinement have produced a new design with the stability, low
noise, low distortion, full power bandwidth, and excellent overload characteristics usually reserved for much more costly
One look inside the SCA-35 will convince you
equipment.
that this is the easiest of all such amplifiers to build. A clean,
uncluttered layout and three factory assembled etched circuit
boards speed assembly and assure consistent performance
from unit to unit, even in the hands of novices. Detailed pictorial
diagrams and step-by-step instructions leave nothing to chance.
Fi Tape Systems Annual, in their Editor's Choice of Hi Fi Systems,
selected the SCA-35 and the FM -3 Dynatuner as offering the "Most Fi per
Dollar" (after choosing other Dynakits unanimously for higher priced
categories) with the following comments: "The SCA-35 is the finest low
powered amplifier on the market, delivers 16 watts (on each channel) from
20 to 20,000 cycles with less than 1% distortion, and below 3 or 4 watts
the distortion is unmeasurable."
High Fidelity Magazine (May 1964) reported: "A kit -built version of the
SCA-35 proved to be an outstanding performer among low power amplifiers. (It) offers performance that belies its cost, meets or exceeds its
specifications, and is in general an excellent high fidelity component."
Audio Magazine (March 1964) concludes: "The SCA-35 ... is perfect for a
small installation where excellent quality, simplicity of construction and
operation, and attractive appearance are requisites."
*Hi
Stereo 35
$59.95 kit
$79.95 assembled
FM -3
$109.95 kit
$169.95 assembled
The FM -3 Stereomatic tuner is the ideal
companion to the SCA-35 for flawless
mono and stereo FM automatically!
PAS -3
$69.95 kit
$109.95 assembled
If you prefer the additional flexibility and matchless performance of the renowned
PAS -3 Dyna preamplifier, the Stereo 35 offers the same power output as the SCA-35
with the recognized advantages of a separate power amplifier.
Complete specifications and impartial test reports are available on request.
DYNACO INC.
3912 POWELTON AVENUE, PHILADELPHIA 4, PA.
Circle 114 on Reader Service Card
AUDIO
15
DECEMBER, 1964
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EDITOR'S REVIEW
IT'S WHITEBEARD TIME AGAIN
Every year at this time it is reputed that the gent
with the white beard comes into sight carrying
goodies for all good audiofans and all other deserving people. Of course we all know that audiofans
are near and dear to his heart since he is a recording
buff himself. Undoubtedly he has made more records
than anyone, including his helper Bing Crosby.
Anyhow, it is traditional to express one's innermost
desires in the belief that Mr. Whitebeard will deliver
the goods like all Whitebeards should. (With all due
apologies to the originator of that ungrammatical
phrase.) After much soul searching, brain wracking,
and a modicum of breast beating we came up with the
following list :
1. An amplifier construction article that is original.
2. A loudspeaker construction article that really
makes a silk purse out of a sow's ear.
3. A non-fattening liquor.
4. An article which explains how loudspeakers may
be tested to take account of room acoustics. A simple
method, that is.
5. An article giving a simple method for accommodating loudspeakers to room acoustics without requiring the services of an expert.
6. A non-fattening liquor that tastes like Scotch.
7. A comprehensive article on recording techniques
which explains the problems and gives a variety of
solutions.
8. A construction article on a professional -quality
microphone mixer using a building block approach.
9. A construction article on a high -quality microphone using generally available materials and techniques.
10. A construction article on an electrostatic loudspeaker using simple techniques.
11. A slightly non-fattening liquor.
12. A dual trace T
X scope at a reasonable
price.
13. A construction article on a flutter meter with
solid-state electronics.
14. Construction articles on a variety of test instruments with solid-state electronics : Audio oscillator,
harmonic distortion meter, IM meter, and so on.
15. A slightly non-fattening liquor that tastes like
Scotch.
16. An article describing and detailing methods of
recording "in the field."
Né:?:
¿
feil;
-2
i
IKI:.
r,.-'.
17. An article describing how disc records are made
from a tape recording.
18. A clearly written article giving the physics of
various musical instruments.
19. A definitive article on grounding techniques.
20. Scotch.
Clearly my wants are rather simple and easy to satisfy. Mr. Whitebeard, if you are reading this, why
don't you mount up and distribute a few of those
goodies? Especially items 3, 6, 11 or 20. Then, if anyone named Morris asks, we will be able to say, "Yes,
Morris, there is a Whitebeard!"
EQUAL IN, EQUAL OUT
At the Audio Engineering Society Convention in
October we heard a paper that started us thinking
again about the problem of microphone impedance.
The problem is the great variety of impedances with
which microphones are made.
But now we have an opportunity. Since transistors
are low -impedance devices, and since they are being
used ever more widely, it would be easy to have all
microphones a standard low impedance. After all most
microphone types are naturally low impedance anyhow. (Except for inexpensive crystal and ceramic
mikes which really don't enter this discussion at all.)
The important part of this thought is that microphones should be a standard source impedance so that
any microphone will operate properly at any microphone input. Naturally there are engineering decisions to make, but the advent of transistor amplifiers
simplifies the problems considerably.
HELLO LARRY
We would like to direct your attention to a new
column and columnist which appears for the first time
in AUDIO this month.
The column is entitled Inside Audio and the columnist is Larry Zide. We did think a somewhat more
humorous title would be InZide Audio, but Larry
didn't appreciate our humor.
Larry is charged with covering the Audio field in
any manner he sees fit, no holds barred. Read his first
column on page 65 and you will see that he charged
right in.
Anyhow, we hope you will enjoy his thoughts.
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AUDIO
16
www.americanradiohistory.com
AmericanRadioHistory.Com
;e:.:
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DECEMBER, 1964
(V-15 AME -1 ELLIPTICAL STYLUS)
NATURAL SOUND BEGINS WITH PICKERING
Whether you own a record changer, automatic turntable, or a professional type manual turntable
Pickering has engineered the RIGHT V-15 pickup for you. Each of these applications requires a
cartridge with specific characteristics and specifications to produce the maximum in NATURAL
SOUND that is possible from the record playing equipment and other components in your system.
If it's RECORD CHANGER application, where high output and heavier tracking forces are
AC -1 Most of you, no doubt are tracking lighter on the late model
required try the
AT -1 Or if a professional type MANUAL
AUTOMATIC TURNTABLES and will use the v-15
AM -1 And if it's
TURNTABLE is your choice you'll need the even more compliant V-15
unexcelled tracking ability you're seeking, you will demand the ELLIPTICAL STYLUS PICKUP
V-15 AME -1 All of these pickups are radically different from any other cartridge. You can see
the difference. You can hear the difference. Pick up a V-15. Note its light weight-only 5 grams.
Perfect for low mass tone arm systems. Now, see how Pickering's exclusive "Floating Stylus"
and patented replaceable V -Guard assembly protects your record and diamond as it plays.
I237
PICKERING & CO., INC. PLAINVIEW, N.Y.
FOR THOSE WHO CAN HEAR THE DIFFERENCE
THE WORLD'S
LARGEST AND
MOST
EXPERIENCED
MANUFACTURER OF
Pickering
MAGNETIC
PICKUPS
Circle 116 on Reader Service Card
AUDIO
DECEMBER, 1964
17
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Should Sherwood's new
solid-state amplifier be rated at
150 watts? ... 300 watts? ... or 100 watts?
Audio power should be one of your major criteria of amplifier performance. The important thing is to use the
same yardstick of comparison.
Among responsible component manufacturers, the
commonly-accepted expression of audio power today is
"MUSIC POWER"- the amplifier's output capability
across the full spectrum of orchestral sound.
If you simply like to play with bigger numbers, multiply
MUSIC POWER by two (the way some manufacturers do)
and you get "PEAK POWER". It's exactly the same rating
but it looks twice as powerful.
But the really important measurement is "CONTINUOUS
SINE -WAVE POWER" with both channels operating
simultaneously. This is the meaningful measurement, used
in laboratory work. It separates the wheat from the chaff.
till you hear
Sherwood's new Tan-
Wait
glewood
system
-way
handles 75
watts of program
material. Unique design of dual, 10"
uniflex woofers
achieves unprecedented 34 -cycle
closed -box reso-
Sherwood's new S-9000 delivers 150 watts of MUSIC
POWER ... 300 watts of PEAK POWER ... and 100
watts of CONTINUOUS SINE -WAVE POWER at
less than 1/2 % harmonic distortion. (At normal levels,
distortion never exceeds 0.15% ) .
-
4
speaker system!
Each six -speaker
nance. Overall re-
sponse: 29-17,500
cps ± 21/2db.
$219.50
-
Unequalled power by any standard is just one of the
important engineering advances built into the new Sherwood solid-state amplifiers. Here are some more :
Military -type Silicon Transistors. Used exclusively throughout
Sherwood circuitry. Twice the heat -reliability of ordinary germanium transistors. Safe for even the most confined custom
installations.
Exclusive transistor short-circuit protection. (Pat. Pend.) New
system virtually eliminates transistor failure or fuse replacement due to shorted speaker terminals or other improper operation.
Additional features: Phono input noise less than -65db., with
no microphonics or hum / Professional Baxandall tone controls /
Tape monitoring and tape -head playback facilities / Stereo
headphone jack with speaker disabling switch / Glass epoxy
circuit boards / Compact size -14" x 4" x 121/x" deep.
Model S-9000
/
solid-state, integrated stereo amplifier
/ $299.50
Also available in a 50 watt Music Power version as the Model S-9500 /5179.50
Walnut-grained leatherette cases for either model, $8.50 Prices slightly higher
For complete specifications and new catalog, write Dept. A-12
SHERWOOD
ELECTRONIC LABORATORIES, INC., 4300 NORTH
in Far West
HIGH
FIDELITY
CALIFORNIA AVENUE, CHICAGO, ILLINOIS 60618
Circle 117 on Reader Service Card
AUDIO
18
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AmericanRadioHistory.Com
DECEMBER, 1964
Low -Cost High -Performance
Volume Compressor
S.
ANDREWS
S.
More than 60 db of compression at less than $15, with fast attack, slow
decay, and low distortion. The heart of this scheme is a photoconductor.
VOLUME COMPRESSION is
one of those
areas with which most audio fans
are familiar and seldom do anything about. The advantages are rarely
realized, and if they are, most feel that
it must be expensive to be good. In the
past this was true. In order to have
good dynamic range, fast attack, slow
decay, and little distortion a compressor
had to be expensive. Now new devices
have made it possible to have a low cost
compressor with all of the above excellent characteristics.
for Compression
Why compress'? The amplitude range
of live musical presentations is often
greater than many recorders will handle
efficiently. Therefore, continual "gain
riding" must be done. However most
people cannot react in 10 milliseconds
and the end result is overload resulting
in distortion.
The Need
LAMP
TO OUTPUT
Fig.
1.
Series lamp compressor scheme.
Fig. 2. Raysistor compressor scheme.
AUDIO
220 k
12Ax7
C
8+ 250 v TO 300 v
.01
0.1
GRID
ADJUST
S
2
IN PUT
.22
MEG
OUTPUT
11.
II
H
O¿
GRID
ADJUST
P
CON. IND.
-
B
COMPRESSION SW
LAMP
ADJUST
TO OUTPUT
Fig. 3. Schematic of compressor-amplifier.
It is obvious that a need for automatic
compression is very desirable. Most commercial recording studios and broadcasting stations use some type of compressing device. This narrows the range
of amplitude variations to controlled
limits. Also, in background music applications such as for restaurants, hotels,
department stores, and so on, wide
amplitude variations are not desired.
Various designs have evolved over a
period of years for compressing and/or
limiting the audio signal for recording.
The simplest of these methods, no doubt,
was using a pilot lamp in series with the
output circuit (Fig. 1). The characteristic of pilot lamps is to increase in resistance as they become brighter (more
signal), and decrease in resistance as
they dim. Therefore, high amplitude
levels will cause the resistance of the
lamp to increase and less signal will
arrive at the output than was fed to the
lamp. Conversely, at low levels, the
lamp will have less resistance and proportionately more signal will reach the
output. The advantage of this system is
DECEMBER, 1964
obvious; the cost is extremely low. The
disadvantages, however, are numerous :
First, it uses a great deal of power ;
second, impedance matching is difficult;
third, it is most effective when the lamp
is glowing rather brightly; fourth, it
has an extremely small dynamic range.
Another commonly used method is to
rectify the audio signal and use this potential to bias a pentode electron tube
and feed the signal through the same
electron tube. As the audio signal
changes amplitude, the rectified biasing
potential changes and therefore controls
the output of this tube. This method, of
course, has a great deal of merit over
the lamp circuit. It does not consume
power from the output circuitry. The
amount of compression can be controlled
rather accurately and, by means of an
RC network, the attack time may be
varied over a large range. It also has
disadvantages. First, the circuit is
rather complex and involves numerous
components, including a power supply,
which makes the cost rather considerable. Second, the audio levels presented
19
www.americanradiohistory.com
AmericanRadioHistory.Com
TO COMP.
ohms) and a low resistance when the
lamp is on (50 ohms).
variable resistor plus a lamp of approximately the same voltage and current
characteristics as the one in the Raysistor in series with the Raysistor. The series lamp would allow the voltage level to
be determined and also could be used to
give indication of the amount of coin pression taking place at any instant.
The series potentiometer could be varied
to give the predetermined level.
The circuit can be made as simple or
as complicated as desired. In my testing
procedure I wanted to have greater control so that I might study some of the
effects of the compressor. I decided to
place an a.c. voltmeter across the lamp
circuit so as to have minimum effect on
circuit operation. I used a VTVM circuit. This circuit, when incorporated in
the unit, will give a continuous indication of the voltage across the lamp and
give a continuous observation during
operation. The VTVM circuit is by no
means necessary.
Design Considerations
The Circuit
'l'here are certain design considerations which must be taken in account.
I have chosen the CK1103 which has a
control lamp with a 5 volt filament
drawing 175 ma. Most amplifiers are capable of producing voltages which will
far exceed this although it is true that
as the amplifier increases in output the
input is decreasing by the action of the
photocell. However, when low -efficiency
speaker systems are utilized, if the bias
of the photocell is set to a point where
the output would be an acceptable level,
then the voltage will exceed lamp specifications. So it is apparent that some
means has to be provided to decrease the
voltage to the lamp.
A reasonable solution is to place a
About the circuit: The first half of
the triode in the amplifier section is a
standard voltage amplifier to compensate
for circuit losses. The output of the next
stage is less than unity. The next stage
is a conventional cathode follower which
is used for impedance matching purposes and to keep the impedance low so
that the high -frequency cutoff is beyond
the audible range if cable lengths are
fairly long.
The output of the amplifier is fed to
the control portion of the Raysistor so
that as the output becomes greater the
resistance becomes less, thus shunting
the grid and reducing the signal and the
output. It takes only 10 ms for this to
(Continued on page 71)
bUc
A
4
I
FULL WAVE BRIDGE
INSTRUMENT RECTIFIER
Y
200 PA
METER
05
METER
ADJUST
10 MEG
1
I
MEG
TO COMP.
YS
Fig. 4. A. C. VTVM schematic.
to the pentode should operate over a
small dynamic range so as not to overload the tube. When this is done, the
problem of hum becomes extremely
troublesome. Special techniques must be
employed with regard to power supply
and layout. Third, if higher amplitude
audio levels are used at a higher level
point in the circuit, then the tube is
not operating over a linear portion of
its curve and distortion may become
excessive. There are many more methods
more or less sophisticated than the
above mentioned. However, these examples are two of the more commonly
found.
A New Device
A new approach is to use a Raysistor.
The Raysistor is a Raytheon trade name
for an opto-electronie component designed for applications in a variety of
control functions, providing comparatively noise free control of a.c. or d.c.
signals over a wide dynamic range,
without transients or contact chatter and
with a high insulation and electrical isolation between the signal and control
circuit. It consists of a light source and
a photo -resistive element assembled in a
light tight case.
The characteristics of the Raysistor
which made it very appealing for use
in compression are as follows: 1. Fast
"ON" action (10 ms) ; 2. Slow "OFF"
action (800 ms) ; 3. Lamp filament
slow response provides an averaging effect; 4. Noise free control; 5. Automatic control; 6. Wide dynamic range.
Placing the photocell portion (a variable resistance element) in the grid circuit of an audio amplifier (Fig. 2),
makes it possible to easily regulate the
signal to the grid circuit since the lamp,
which is across the output terminals of
the amplifier, glows brighter during
loud passages and dimmer or off during
soft passages. The photocell has a high
resistance when the lamp is off (10'
RESISTANCE BETWEEN SIGNAL TERMINALS-OHMS
Fig. 5. Typical curve of resistance versus control voltage.
AUDIO
20
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DECEMBER, 1964
Recording the Muse on Tape
ARTHUR C. MATTHEWS
Techniques for recording dramatic
productions of an amateur group
DOING a play down at the
school, could you record it for
IWE'RE
a
us?"
"I'll admit that the convention hall is
poor place to do drama, but we've just
got to find a way. How about recording
it?"
"Well, I wrote this play, see, and I'd
sorta like to hear what it sounds like.
Could you get a group together and tape
it in stereo?"
If you haven't been approached yet,
you may be, then what? If you know
something about recording music or
musicals, the equipment may be the same,
but the techniques definitely are not.
As a result of six years of recording
drama in stereo, I'd like to give you a
few hints that I've found valuable. Remember that the primary purpose of recording drama is that it be heard. If it
cannot be heard, and heard clearly, without strain in an ordinary living room,
much of its effect will be lost.
Acoustic Environment
Acoustic environment is the feeling of
the room which a good recording in
stereo conveys. The wall of the listening
room disappears and the listener is transported into a concert hall, in the case of
music, or into another room, an outdoor
scene, or whatever acting area is required
in the case of a play.
A room has a characteristic sound. If
you've ever slept in a strange room overnight, you know the sensation of waking
up in a different acoustic environment.
Another indication of room differences is
demonstrated if you are brought into a
room which is dark or if you are blindfolded. In most eases you can tell the
difference between a small room and a
large one.
When staging drama for stereo recording you ought to decide what kind of
acoustic environment is necessary for the
play you are producing.
An outstanding example of annoying
acoustic environment is the dise that
Basil Rathbone made of Poe stories. Mr.
Rathbone sounds as if he were recording
in an enlarged rain barrel. The extra
reverberation might be suitable for the
catacomb scene in "A Cask of Amontillado," but it hardly suits the other
* Devry Technical Institute, 4141 W. Belmont, Chicago, Illinois 60641
AUDIO
stories.
Imagine Mr. Rathbone standing on
the edge of an empty loft, on a slightly
raised platform, book before him, microphone on the floor about ten feet away.
He gazes into a murky Poe vastness,
empty except for a recording engineer
off in a corner somewhere. Too bad
nobody came to absorb some of the
sound. Such a vast hall is annoying if
there is no artistic reason for that much
space.
Acoustic environment ought to consider "living -room -ability." How will it
sound to a few people in a living room
somewhere? Music can get away with an
"enlarged" space because we know that
an orchestra requires a large performance area and space for the sound to
develop.
Live Recording
Not much can be done about acoustic
environment if you make a live recording, but there are some advantages. The
hams (actors to you) can go on about
their business in front of an audience,
and usually give a better performance.
The biggest difficulty is miking. A
minor problem is audience noise. Should
it be minimal or part of the recording?
The answer to the noise question is
psychological. If you are just making a
"memories" recording for the cast and
director, they simply want to hear how
they sounded. Audience noise isn't a
problem as long as it doesn't interfere
with intelligibility.
If you're going commercial either for
broadcast or disc, then the psychology
of the listening situation is important.
Comedy seee:9 to require laughter.
Many TV programs add "canned"
laughter to their comic gems, assuming
that laughter will encourage the audience
at home to laugh too. There is a squared
correlation in opening the can : I = L2,
where I equals the inanity of the material, and L equals the quantity of the
laughter added. In your recording
you'll be stuck with the laughter, or lack
of it, that a real audience supplies. You
can always doctor the recording.
Still, my own experience leads me to
believe that laughter, canned or live, does
not add anything to the home listener's
enjoyment of a play. While a matter of
taste, you will decide which solution you
prefer, for the answer dictates the mike
setup.
There are several mike patterns : 1.
Omnidirectional mikes pick up well from
all directions; 2. Bidirectional mikes pick
up from the front and back, in a figure
8 pattern; 3. Cardioid mikes pick up in
a "heart shaped" pattern from the front;
4. Super-directional mikes pick up in a
very narrow beam.
For most rooms, bidirectional and
cardioid microphones give best results.
If the room
is small, an omnidirectional
mike picks up the reflections off the
walls. If you have an ideal recording
studio, the omnidirectional pattern makes
an excellent recording. If the studio is
less than ideal, the other two types are
better choices. Cardioid and bidirectional
mikes are best if you want to keep audience participation to a minimum.
At Luther North where I recorded a
number of plays, I also installed a sound
re -enforcement system. The auditorium
is one of those multi -purpose rooms
which are better named no purpose. A
good theatre usually needs an acoustically live ceiling. A cafeteria -study hall playpen requires a dead ceiling. Guess
who wins?
The low ceiling (13 ft. 6 in.) combined
with the 3 -ft. stage height put the actor
within 4 ft. of the acoustic tile ceiling.
Unless an actor has iron lungs, nobody
can hear him 20 ft. away. If he can be
heard, he'll probably end up in an iron
lung after one performance. Sound re enforcement is necessary, no matter how
much the director may object.
The re -enforcement at Luther is stereo.
Four Electro -Voice Sound Spot (644)
mikes are spaced equally across the 30 -ft.
stage opening. The four mikes are jacked
into the inputs of a Crown 700 series
recorder. The outputs of the recorder
feed a Dynakit preamp-amp combination. The amplifiers supply a series of
speakers above the proscenium arch. A
slight blend of channel A and B is used.
Fortunately the mikes hang relatively
low. If, however, the stage you're going
to work on has a higher opening, try to
come as close to the actors as possible.
This may mean dropping the mikes
down into the stage setting. Of course
the director may complain that you are
ruining his decor. Altec lipstick mikes
are one solution. The other is to place the
21
DECEMBER, 1964
www.americanradiohistory.com
AmericanRadioHistory.Com
i
mikes in the footlight trough (if there is
one, they are fast disappearing) or on
small floor stands across the front of
stage. Be sure the front curtain doesn't
take the mikes with it when it opens or
closes. For each 10 ft. of width beyond
30 feet, add one mike for each channel
(rule of thumb).
If the acting area is more than 15 ft.
deep, you may have to add a line of
microphones for the back of the stage.
Try to keep the mike cables away from
the lighting cables, you may induce some
hum.
If you
use sound re -enforcement which
has a means of separating the line after
preamplification and before the final
amplifier stage, I suggest some form of
compression.
A compressor boosts the apparent
loudness of low volume material and cuts
the apparent loudness of high level material. A compressor tends to make both
loud and soft passages move toward a
middle ground. In recording music, large
volume variations tend to produce exciting music. In recording plays, such large
volume variations make some parts inaudible and others too audible.
Compression will not only help the re enforcement, but will permit you to ride
gain a little higher and pay more attention to the play and less to meter
needles or flashing eyes. The flashing
eyes of the leading lady are much more
interesting.
A simple way to compress without
ruining the budget is to insert a Fairchild Compander, a Knight KN 777 expander -compressor, or build your own
(see Andrews article in this issue), between the preamp and the amp. (See
Fig. 1.) A "Y" connector at the output
of the compressor feeds both the re -enforcement amplifier and the tape recorder. Compression can be added to the
playback, but compression before the
recording helps make a better signal-tonoise ratio.
WARNING: a compressor by its nature increases background noise level
during quiet passages.
If you've decided that laughter is
needed to complete a comic illusion, bidirectional microphones are necessary.
Omni-directional mikes are possible but
require a good acoustic environment.
I recorded a version of "The Doctor in
Spite of Himself" (Molière) with the
North Park College Players using two
bidirectional ribbon mikes. We had a
separate re -enforcement system. The
mikes were placed on stands directly in
front of the stage and feed into a Concertone 505 recorder.
Two problems : 1. Two mikes weren't
enough, especially since there was a great
deal of action upstage; 2. The front of
the stage is too far front for bidirectional mikes (they tend to pick up the
audience better than the play).
It seems that Jon and Lars (this is a
CONTROL
VOLTAGE
MIXER
1
COMPRESS.
-
TAPE
AMP
AMP
Fig. 1. A compressor helps sound rein-
forcement and taping.
Swedish school or they might have been
Pat and Mike) were sitting in the front
row. Kids have few inhibitions so they
laughed and laughed and talked about
the play. As a director I was happy. As
a recording engineer-listner, I was not.
Two enthusiastic audience members giggling in the front row are annoying. A
better perspective on the laughter was
possible by hanging the mikes from the
top of the proscenium arch pointing so
that the laughter is picked up as a
bounce from the ceiling.
I have never been able to find a satisfactory compromise between live and
studio recording. If you record live you
have noise and level problems as well as
an artificial sound. If you record in a
studio the actors lose part of the edge
to their performance.
Studio Recording
A recording in a good acoustic environment seems preferable to one with
the actors projecting for a large audience (to listeners in a small room). Per-
haps a special recording session with an
audience can he arranged. Shoot all people with smoker's hack, hay fever, and
common colds at the door!
Deciding that studio recording is the
lesser of two evils brings you smack
against three major problems: 1. Studioplayback area; 2. mike type and placement; 3. stereo movement, how much and
how.
The studio need not be a professional
recording studio complete with floor suspension, but it should be located where
the noise level is low. Probably at least
a block in all directions from main traffic arteries. The further away from the
mikes the actors work, the higher you
have to raise the level of the mikes. Noise
in the background comes way up too. If
you have a noisy background, work close
to the mikes.
In recording "My Own Song" I was
faced with a shift in flight pattern.
O'Hare International Airport sends up
jets like clouds of mosquitoes. The mosquitoes do not ordinarily bite, but when
the wind shifts, every jet in the U. S.
makes a pass over the "studio." We con-
sulted the augurers about the future
and moved the session to a more propitious time.
The size and shape of the room are important too. You might think offhand
that a recording on the stage is best. But
this isn't so in many cases.
The recent recordings of "Strange Interlude" (Eugene O'Neil) and "Who's
Afraid of Virginia Wolf" (Edward
Albee) are good examples. The O'Neil
shifts acoustic environment for indoor
and outdoor effects. Virginia's tinkling
ice cubes are sometimes irritating but
effective. The recording of "Waiting for
Godot" (Becket) while not in stereo, has
an excellent perspective (distance of
actors from the mike).
Since most plays take place in a room,
the studio should probably sound like a
room, not Howe's Cave or The Chicago
Stadium where Al Melgard, the organist,
plays for ten minutes and then rests ten
to let the sound catch up. Take the mikes
to several locations. Remember, if the
sound is too dead the voice will not seem
to be in a room and the stereo effect is
lost.
Reverberation can be added artificially, but I have yet to hear a satisfactory reverberation system for voice. I
may have heard one so clever that I
didn't notice, but most are abominable.
The room should sound "big enough"
to be different from the listener's normal environment, but not cavernous.
Symphony Hall in Boston is ideal for
the Berlioz Requium but a little large
for a play.
It is impossible to be too exact about
the kind of room that will sound best. A
room smaller than 10 x 15 ft. with an
8 -ft. ceiling is probably too small. Rooms
with acoustic tile ceilings are probably
out in most cases.
The ceiling of a room has a great deal
to do with how sound develops. A room
with plaster walls, wooden floor, without
furniture or carpets will probably be
too live. Brick and cement block interiors, because of the roughness of their
surfaces, tend to be interesting acoustically.
There is no really ideal room. As director you'll have to decide what kind of
sound you're looking for and then listen
for a room. But since your ears aren't
at all like a microphone, you'll have to
perform some tests on the room.
To test a room, place your mikes
across the short side of the room at one
end. Make a "take" (recording) of some
material from the play; move the mikes
closer to the far wall, retake. Do this several times. Then make tests across the
wide side of the room. Try shades up
and down. Drapes opened and closed.
DO NOT listen to the playback in the
same room. The listening room should be
an "average" living room (whatever that
may be).
By all means try several rooms. And
sound is
don't be confused by looks
what counts. Bruno Walter recorded his
California dates in an absolutely hideous
looking room; the sound was excellent.
When you are satisfied with the hall,
...
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22
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DECEMBER, 1964
prepared for changes as the humidity
and temperature change.
You might start your tests on stage by
closing the front drape. The stage may
sound too big
add some more drapes
to the sides. Try recording with the actors playing with their backs to the rear
wall, talking towards the front drape.
The bounce off the back wall might add
just enough extra liveness. Experimentation is the only way to be sure. There are
too many variables.
In considering the studio, consider
where you want to put the recording and
playback equipment. There are two
theories here. Some directors like to be
in the same room with the actors and
wear earphones. The director must hear
how the recording sounds, not how the
actors sound in the actual room.
Earphones are dangerous unless there
is a device like the Bauer circuit incorporated. Without some mixing of the two
channels you will hear "binaural" (two
ear) recording through the headphones.
The separation between channels is made
greater than the listener at home will
hear. The Bauer circuit mixes L and R
and puts you back into a room. At best,
earphones are dangerous.
The room in which the director listens
should be as much like a normal living
room as possible. The speakers should
not emphasize a particular frequency
range. The director and engineer may
have to be located some distance from the
recording area. An intercom may be
necessary.
Preliminary and final testing of the
recording should be done by someone
who is not familiar with what you did or
are doing. He (or she) should be someone you believe to have taste, someone
perhaps familiar with drama, but not
with the play. Your judge should be a
"new ear" which will not be hearing
things not on the tape.
I often despair as a director because
I'm so close to the show that I can't hear
it any more. Just recently my Christian
Theatre Company performed in the Valparaiso University Gymnasium before an
audience of 600 people. I'd heard the
play so often that I simply could not
tell whether the sound re -enforcement
system helped at all. Fortunately it did,
but I wouldn't have known. I'd directed
the play with two groups and had written it. You can't find a more prejudiced
critic.
A quick review then A studio with
right liveness; a playback room with
right deadness; intercom. Fine you say,
now how do I set up the mikes (Always
questions). How you set them up will depend (as you've guessed) on the kind
of effect you are looking for.
is necessary. This "D" should not probably be over four feet for most types of
mikes. Remember, the reason you went to
studio recording was so that the actors
wouldn't have to project and seem forced
in their speaking.
In recording a live performance of
"Christmas 1960" with a speech chorus
of 100, intermixed with various solo
be
ACTOR
...
:
Microphone Placement
There are two basic techniques I use
curtain and three area. In the curtain approach, the microphones are set
...
AUDIO
ID
®----®
1
-D -
-n
®----®
2D
D-.1
-1.
D=AVERAGE WORKING DISTANCE
Fig. 2. Spacing microphones
based on
average working distance.
Fig. 3. Using cardioids for the
"curtain"
approach.
Fig. 4. Using cardioids and omni's for
"three -area" recording.
up so that an even pickup of sound
seems to spread across the listening
room. This might be accomplished with
four (or three) omnidirectional microphones. I have used Sony C37A's with
some success.
The exact spacing will depend on the
size of the room and the kind of acoustic
environment you want.
The distance between the mikes (D)
should be the same as the average working distance of the actors from the mike.
This average (middle) distance is the
one at which much of the acting is done.
A shouty play will probably have a
greater "D" than a quiet play. Start by
placing the center mikes 2D from each
other, and the left and right mike 1D
on either side of the two center mikes
(Fig. 2) . The 2D figure is not a sure bet,
but it is a place to start. You may have
to move the mikes closer together, approaching 1D or less.
If you use three mikes, the single center mike will have to have two jacks on
the far end of the cable. One jack will
plug into each channel. The three mikes
will be separated by 1D each. NOTE
The distance factor will change if the
actors are closer than two feet to the
mikes, since the square law does not
apply in this case.
The curtain of sound can be created
(Fig. 3) using cardioid and bidirectional
:
patterns. Experimentation with spacing
speakers and small groups, I was able
to use spacing greater than 4 ft. Two
mikes were placed about 6 ft. in front
of the chorus, up to full height on the
stand. The mikes were bidirectional ribbon mikes (B&O 50's). The mikes were
separated about ten feet from each
other.
Since the recording was done in a
gymnasium, the reflection off the opposite wall and ceiling was picked up by
the back of the mike. For the solo voices
we used two E -V 664 eardioid mikes
separated about 30 ft for a real L and
R isolation. The left and right mikes
also picked up the ends of the chorus,
although they were 12 ft from the front
of the group.
An ideal solution, which I haven't
tried but am looking forward to is two
or four AKG C-12 microphones. This
type of microphone has a control for
complete pattern variability from cardioid to omnidirectional. Test recordings
in various pattern positions can be made
and the best one chosen.
Another experiment involves four bidirectional mikes mounted in an unusual
way. Each channel consists of a pair
mounted one above the other (colinear)
with patterns at 90 deg. to each other.
The pair jacks into two separate inputs
of the same recorder channel. B&ODynaco makes a colinear unit (model
200) which might be ideal. Consider the
"front" of the microphone the pattern
which the actor faces. It is operated at
normal level. The "side" of the microphone (picking up reflected sound) is
varied in volume until the kind of
acoustic environment needed is achieved.
The experiment ends up with a sort of
variable omnidirectional mike. The
"side" mike can be rotated until the
angle between it and the "front" mike is
0-deg. All sorts of possibilities!
Finding the correct "D" is critical.
If you place the mikes too far apart, the
actors will drop in and out as they move
from L to R. This simply sounds like the
microphones are too far apart.
If the mikes are too close, the L and R
channels will blend and the sense of
movement will be reduced. Don't make
the sound curtain too wide from L to R.
A wide curtain could expand the listening room to disturbing proportions.
Three Area
The three -area approach uses three
or four cardioid mikes or two bidirectional mikes with a spacer. In recording
The Rick Mark Show, about a teenage
23
DECEMBER, 1964
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hero, the separation problem was solved
by the nature of the play. The stage
represented the dressing room of the star
of our show and the dressing room next
to it, where Carlotta Parks and Arthur
Hopkins waited to go on Rick's show.
For this recording I used four E -V
644 Sound Spots arranged so that the
actors played close to the right mike
when in Mark's room, and close left
mike when in the other room. The center
mikes picked up a little of the talk in
both cases to give the in -a -room effect.
This is really a two -area recording.
"Welcome Angels" presented a different problem. Two Angels, Miss Light
and Mr. Dark, have come for the Patient, who is dying in a chair center.
When he dies at last, his final words are
so equivocal (neither hot nor cold)
that Dark and Light can't decide who
gets him.
Because I wanted to contrast good,
evil, and the poor confused patient in
the middle I used the following setup
L mike E -V 666 cardioid, two center
mikes (10 ft. from L mike, 10 ft from
R mike, separated by 4 ft) Sony C37A's
in omindirectional pattern, R mike EV
666 cardioid (Fig. 4).
The three -microphone three -area technique uses three identical mikes, separated 2D or more. The center mike terminates in two jacks, one plugged into
L and one into R channel. There is
some danger in this three -mike technique
that the center channel will have a different frequency response because of the
"bridging" device.
Two Dynaco-B&O mikes with an
acoustic spacer are used in the three area technique. The mikes are not set
up as they would be for ordinary stereo.
The mikes are turned so that at the
front they face the centerline of the
spacer, giving a close center channel.
The backs of the mikes are turned away
from the spacer which acts as an acoustic barrier between L and R channels.
Thus there is a dead spot as an actor
moves from left -center -right. I put adhesive or masking tape on the floor to indicate to the actors areas to keep out of.
The actors moved between areas during
pauses. They worked from 21/2 to 4 ft
from the mikes depending on the scene
and the power of their voices.
One point I learned during this production, that the floor should be marked
with radial lines around the mikes so that
the actors can find a position and keep
it. Exact positioning helps in editing.
A variation on this setup uses the
two bidirectional mikes and an omnidirectional suspended over the basic
mike setup (71/2 to 8 ft. off the floor)
with a double jack on the end feeding a
sort of center room air channel. The experiment was not too satisfactory. The
ceiling of the room was too low and the
room too small. A little experimentation in a larger room might prove out
:
the technique.
Amateur actors do not have the ability
to control their voice volume in the way
a professional actor or announcer can.
I know it took me a full summer at
WFIU in Bloomington to get the technique. After the play was edited, I found
the volume variation from scene -toscene and voice -to -voice too much and
compressed about 20 db in playback.
There are then several mike setups
for each of the two basic techniques.
Curtain of sound is the most difficult
because it requires an eveness which
takes experiment to achieve. The three
area, L -C -R, has something to recommend it, especially with amateur recordists without all kinds of time and equipment.
Movement in three -area is constricted,
but it is thereby easier for the audience
to visualize exactly what is going on.
In a theatre the audience sees the actors
moving
at home the listener has no
way to tag who is where.
Plays with large numbers of characters
and constant violent action are probably better left out of your recording
career until you can handle the me-
...
dium.
Problems of movement and problems
of voice color are questions of taste, but
some microphone problems are questions
of mechanics. Some condenser mikes
seem to favor "S" sounds. With ribbon
mikes plosive sounds (p, b, t, d) and
fricatives (f, v) are likely to drive the
ribbon out of its normal vibration circuit
and set up low -frequency pops or thuds.
The closer the actor is to the mike, the
worse the problem. Back the actors off,
or teach them to control their enthusiasm
on p, b, t, d, f and v. Dynamic microphones are not as sensitive to fricative
problems, but may be popped by plosives
under some circumstances. Fire all
poppy, hissy, or fffffffy actors.
Staging for Recording
Now some aesthetic problems. Too
much movement can be annoying. The
listener in his home without a book cannot be following hopping, skipping, and
jumping actors. As a director, sit down
with the book and decide who should be
where, when. If the.,scene is intimate,
play it with the actors close to mike and
close together. Shouting scenes (for the
sake of audience, actors, and engineers)
are best played further away than
"Dn
Most plays break up into what directors call "French Scenes." A French
Scene begins or ends every time an actor
enters the set or leaves the set. In some
cases, a different scene begins if there
is a major change in idea. Breaking the
play into French Scenes can be helpful
in deciding movement.
The director must clearly establish
entrances and exits. For example, the
kitchen is middle, right; the door to
outside is center, far distance; the bedroom is near left. Unless you want a
peculiar effect, the actors should not
turn their backs as they exit. Move out
hacking up.
In the three -area approach, divide
the play into French Scenes and decide
which of the three major areas you intend
to use for each scene. Restrict movement in most cases to movement to or
away from the mike. Once the actors
know where to stand, make them stay
there. Movements of heads or feet can
cause an audible shift, especially with
the two bidirectional microphones and
spacer technique. The center area in this
setup is particularly sensitive.
Forget any experience in directing
for the stage. Remember what you
learned from radio, adapt it. As in radio,
keep the actors close to the mike, especially in a poor acoustic environment.
Avoid the stage director's temptation to
move actors back and forth. The actors
can fade into or out of a scene, but
do not play important scenes far from
the mike "D" or less!
Alternate close, medium, and far distance scenes. The very close -to -the -mike
method can be used for 18th century
plays where asides abound and in
Shakespeare for soliloquies. Again experiment will tell.
Another directing problem : Should
the recording be made from beginning to
end without changes of scene order If
the actors have rehearsed for some time
together, yes. Even though they do not
have an audience, some sense of performance is possible.
But in recording with a drama class,
for example, usually it is not possible
to schedule four-hour sessions for everyone at once. Break the play into French
Scenes (it's surprising how often only
two or three characters are necesary at
one time) ; match the actor's time against
the scenes, and set up the schedule.
Under these circumstances, it's probably best to record the middle scenes of
the play first. Film producers often use
middle, beginning, end as their filming
order. At first the actors aren't quite in
character. If you record first things first,
their characters are not set sufficiently
to project the personality. If you record
the last scenes, they haven't built the
emotional intensity for the scene. The
middle scenes, then, seem to be safest.
The pieces and bits recording method
should be scheduled: several complete
read-throughs of the play, marking
scripts with ideas of character, emotional climax, important lines (point
lines), speed, and mood. Help the actors
get an idea of the character they are to
play.
In working with individual scenes,
my approach is to assume that actors are
intelligent human beings who respond
to someone who helps them release and
(Continued on page 62)
°?
AUDIO
24
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DECEMBER, 1964
Electronic Organ Tone Coloring
D.
WOLKOV
Electronic organs achieve the required tone coloring by a variety of processes. Here is a description of these techniques.
FASCINATING, AND STILL DEFINITIVE,
Aresearch effort on musical scaling,
harmonic overtones and beats is described by Helmholtz in his "On the Sensations of Tone as a Psychological
Basis for the Theory of Music.11 Particularly, those readers who desire a deeper
understanding of what electronic engineers need to know about music so that
oscillators and filters can be converted
into a musical instrument should refer to
Part III, pages 234-371 of this book.
Although his book was written about
100 years ago, the theories and explanations have withstood the tests of inspection and challenge. Without describing
how these well understood (but not defined here) laws pertain to the physiology and psychology of music, we will direct our interest in this article to 1.
:
Harmonic analysis. 2. Harmonic synthesis. 3. Passive electrical filters as
analogs to mechanical formants. We will
also discuss how these techniques are
used in modern electronic organs.
Later we will see that the basic constituent of sound is the sine wave. To
understand sound, we must first understand simple harmonic motion. The
mathematics and basic concepts can be
found in any text on mechanics.
An elastic body undergoing vibration,
be it a violin string, or a flute, vibrates
Helmholtz, "On the Sensations of Tone
as a psychological basis for the Theory of
Music," Dover Publications, N. Y., 1954.
IDEAL WAVE
(A) ADDITION OF FIRST
3 TERMS
NV1
(B)
ADDITION OF
analyzer. (Courtesy
synthesis.
Case Inst. of Technology.)
in a complex mode, but it can be shown
that the complex mode can be trans-
the early 1900's, an optical -mechanical
microphone, which was flat from 0 to 10
lated into a system of simple harmonic
motions by harmonic analysis.
Dr. D. C. Miller in his book, "Science
of Musical Sounds,"2 provides a fascinating picture of techniques of harmonic
analysis before high -quality microphones, amplifiers, and tape recorders
were known.
One of the more interesting devices
described is Koenig's apparatus (1862)
in which a burning gas jet was modulated by sound. The combination of a
microphone by Bell and an oscillograph
by Blandell (1893) is also described by
Miller. He concludes "that mechanical
and electromagnetic factors produce appreciable alterations of the wave forms"
(low fidelity?). Also of interest is the
Scripture machine which made optical
traces from phonograph records-one
turn of the 78 -rpm record in five hours
and an additional optical magnification
of 300. The first real technical breakthrough was Miller's phonodiek, built in
kc.
FIRST 15 TERMS
Fig. 1. Example of harmonic
AUDIO
Fig. 2. Mechanical harmonic
' D.
Fourier's Theorem, published in Paris
J.B.J. Fourier, states
that a curve, having a wavelength 1, can
always be reproduced in one particular
in 1822 by Baron
way by compounding simple harmonic
curves of suitable amplitude and phase
having the same axis and having the
wavelength l (fundamental) 112 (first
harmonic) 113,114 . . . lin (n -1 har-
monic). There are other restrictions on
the theory for which the reader is referred to Wood,3 Pender/Mclllwain,4
and Woods.5
It should be noted that Fourier's
theorem assumes two conditions regarding the form of the complex vibration
1. The displacement must be single valued and continuous. (It is obvious
that this condition is fulfilled in all
eases of mechanical vibrations since a
:
3 A. B.
Wood, A Textbook of Sound,
The Macmillan Co., 1937.
Electrical Engi4 Pender/McIlwain,
neer's Handbook, John Wiley Sons, N. Y.,
1950.
Miller, The Science of Musical
Sounds, Macmillan, N. Y., 1916.
C.
DECEMBER, 1964
5
F. S. Woods, Advanced Calculus, Ginn
New York, 1934.
C Co.,
25
www.americanradiohistory.com
AmericanRadioHistory.Com
particle cannot actually have two different displacements at the same instant of
time) ; 2. The displacement must always
have a finite value (this condition also is
clearly fulfilled in the case of sound).
Taking the square wave as an example of the application of Fourier's
theories, Fig. 1 shows the graphical
addition (harmonic synthesis) for 3 and
15 terms. It should be noted that at 15
terms the square wave is fairly well
approximated. A rigorous mathematical
proof and further demonstrating examples are contained in Rainville's text.°
In a similar manner, we can analytically find the harmonics of any periodic
wave if we can describe its function. If
we cannot then we must resort to a
mechanical analysis (which is a numerical approximation method using Fourier
Analysis) or a point -by -point integration using a digital computer.
Back in the early 1900's, digital computers were an unforeseen art. This did
not stop the researchers in the harmonic
analysis of sound. Instead they built
analog computers. Many accurate machines of this type and of great accuracy
were built. Figure 2 shows a five -coefficient harmonic analyzer and Fig. 3
shows the details of a rolling -sphere
integrator. Figure 4(A) shows an oscillogram of an organ pipe sound and Fig.
4(B) shows its harmonic content when
analyzed by a mechanical harmonic analyzer. Figure 5 shows the recheck when
the function is recomputed from the
coefficients, frequencies, and phase shifts
given by the analyzer.
When an oscillograph of the sound
from a bell is inspected it turns out to
be a non -periodic curve, thus, Fourier
techniques are not applicable. This is
evidenced in the practical art Schulmerich supplies mechanical chimes and
Artisan supplies bells and other percussion instruments as adjuncts to electronic organs. We conclude that periodic
sounds can be synthesized by harmonic
oscillators and aperiodic sounds cannot.
Further investigation reveals that it
is important to plot the magnitudes of
the amplitudes against the frequency of
the harmonics. The relative amplitudes
of harmonics for the violin, french horn,
and flute were determined by Dr. Miller
using mechanical recording and mechanical integration.
By 1929, the Bell Telephone Laboratories were able to determine amplitudes
and frequencies by electronic means?
They used the apparatus shown in a
block diagram in Fig. 6. The fourteen
bandpass filters were designed so that
they presented a uniform impedance of
:
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Del Padre Supply
Madison
Milwaukee
Wausau
Electricraft, Inc.
Dean's TV and Radio
Specialized Sound Systems
Bradford's
Hi Fi Fo Fum Inc.
Bob's Musical Isle
If a dealer is not in gour local area, write:
SIICItE BROTHERS, INC., 222 Ilartreg Ace., Evanston, III.
AUDIO
26
www.americanradiohistory.com
AmericanRadioHistory.Com
DECEMBER, 1964
Over two years ago, word leaked out (as it will) that
Shure, one of the world's most respected manufacturers of high fidelity components, had embarked on an
epochal project: the creation of a perfectionist's compact stereo system. A high fidelity system that conjoined
optimum sound and minimal size.
A formidable and dedicated group of development and
design engineers was given carte blanche.
Independent high fidelity authorities were flown in for
repeated consultations. Their
recommendations and comments provided a demanding
framework for Shure engineers.
PERFECTIONISM
Prototypes were modified and improved...
and improved again ... and again.
The monies and skills appropriated to the
by ANY standards.
project were sizable
Perfectionism is not inexpensive,
ever.
-
THE M100 SYSTEM
home -listening requirement,
the M100 is also recommended for use in
schools, hospitals, and other institutions. It is
Underwriters' Laboratories, Inc. listed.
Space is not sufficient here to list all the
IS NOT
M100's pertinent specifications.
They are for a system of this size,
INEXPENSIVE,
The result of this highly disciplined
creativity is Shure's M100 Maximum Performance component high fidelity
system. It is not just good, it is great.
singular. We will be happy to send
complete specifications to technically oriented music lovers.
LIMITED QUANTITIES
Because of the detailed craftsmanship, large
amount of hand -labor, and rigid quality control and inspection techniques involved, the
number of M100 systems manufactured will be few.
They will be available only through a select group of the
most experienced high fidelity consultants and dealers.
We cannot promise immediate delivery. For perfectionism cannot be mass produced.
EVER
will re-create your favorite records with a
sound quality that is remarkable in its naturalness and exciting in its impact. It is unlike anything
previously available in compact systems-save perhaps
a highly -inspired custom component rig costing two
(or more) times as much.
It
The M100 embodies significant and unique engineering considerations, such as a solid-state pre -amplifier/
amplifier developed and produced by Shure with more
than ample power to drive its two total -range, ultra compact multi speaker systems, also designed by Shure.
And, it features the renowned Shure Bi -Radial Elliptical
Stylus in the famed V-15 Stereo Dynetic 15° tracking
cartridge. Naturally, it cannot scratch records. Dual's finest precision Model 1009 automatic turntable is standard.
The M100 can be used with
AM, FM, Multiplex tuners, or
be used as a public address
system. Ideally suited for every
Because of the singular standards for sound and for
size that were set for the M100, few components were
judged to be satisfactory for inclusion in the unit.
Consequently, the Shure design staff (that developed
the unique Dynetic cartridge which made true high fidelity stereo a practical reality) designed many of their
own components. In addition, quality is controlled by
the famous Shure Master Quality Control Program.
THE M1OOL
PORTATIVE SYSTEM
In two instrument cases. Recommended for serious listening among
music lovers on the go: armed forces
members, boat owners, college students, school music directors, or anybody given to travel. Or summer
cottage owners, of course. $389.00.
L
THE M100W LIBRARY SYSTEM
Impressive solid walnut cabinetry
designed to complement the decor of
modest or magnificent homes and
apartments. $450.00 complete.
- HURE moo
THE SH URE ENGINEERED SYSTEM OF
LABORATORY MATCHED HIGH FIDELITY COMPONENTS
Shure Brothers, Inc., 222 Hartrey Ave., Evanston, Illinois
Circle 118 on Reader Service Card
AUDIO
DECEMBER, 1964
www.americanradiohistory.com
AmericanRadioHistory.Com
27
:
pattern the tone color is said to possess
a "formant" characteristic.
The formant may be simply defined
as a frequency range in which the harmonic components of a complex wave
Fig. 3. Rolling sphere integrator -harmonic
analyzer. (Courtesy Case Inst. of Technology.)
600 ohms at all frequencies. Only one
ing engineering effort not necessarily for
filter at a time was used, this one being music but for the resolution of flutter
connected to the 600 -ohm measuring problems in missile and high-performcircuit while all the others were termi- ance aircraft.
nated by 600 -ohm resistances.
I do not know whether harmonic anToday, harmonic analysis is a continu - alysis of musical sounds is being done
anywhere today as a research project,
(A) HARMONIC COMPONENTS
but if it were, how simply it could be
ti
done using high-fidelity techniques. The
º
3
4
s
7
s
10
i
It
40
30
(B)SPECTRUM
dependently of theory, is rendered probable by the fact that the ear really
effects the same analysis, and also by the
circumstance already named, that this
kind of analysis has been found so much
more advantageous in mathematical investigations than any other."
Formants
20
10
o
sound from the source would impinge
on a high -quality recording -studio microphone, be amplified in conventional
manner, and recorded on tape, for immediate or delayed playback onto an
oscillograph. The harmonic coefficients
and phase shifts could be determined
easily by computor techniques.
Intellectually, we conclude that the
theorem of Fourier has shown it to be
mathematically possible to consider a
musical tone as a sum of simple tones.
We do need to enquire as to whether
these partial constituents of a musical
tone can be reconstituted into a complex
wave and will ear hear the original
sound. Helmholtz said :1
"That this is indeed the case, that this
analysis has a meanie, in nature in-
Y
3
4
5
s
7
s
s
10
ft
12
HARMONIC NUMBER
Fig. 4. Harmonic analysis. (Baldwin
ano Co.)
Pi-
As has been mentioned earlier, the
harmonic content of a tone is dependent
upon the fundamental frequency. For
some instruments such as the oboe, bassoon, French horn, and trumpet, the
dependence is pronounced. To the extent
that this dependence follows a definite
are prominent relative to harmonics at
neighboring frequencies. A given tone
color may possess more than one formant. Figure 7 is an illustrative example
of the effect of a formant characteristic
upon the spectrum of a tone of variable
fundamental frequency.
Although the tone spectrum of an
organ stop or of a single instrument will
vary considerably with fundamental frequency, there are large differences between the spectra of various stops or
instruments for the same fundamental
frequency. For tones in the octave range
above middle C, for example, the spectra
shown in Fig. 8 for flutes, reeds and
strings are fairly typical.
Each successive harmonic of a flute
tone wave will be ten db or more lower
in level than the preceding harmonic.
For higher pitches the higher harmonics
are even less apparent. Reed instruments
Fig. 5. Harmonic synthesis-proof of har-
monic analysis.
and the reed class of organ stops generally have well-defined formant characteristics while strings have a large
number of harmonics of comparable intensity. The string spectrum shown is
for a tone on a violin E string.
A fine summary of the mathematics of
music appears in an article by Sir James
Jeans.8
Let us return to the amplitudes of
harmonics. If we had a bank of sinewave oscillators available to us, we could
key in appropriate frequencies and attenuate them to the harmonic pattern of
various instruments. The effect would
be frequency addition with each proper
harmonic having its proper amplitude.
Our electrical addition would recall the
technique shown in Fig. 1 when we attempted to duplicate a square wave.
In theory, and in practice, the sound
that one would hear from a loudspeaker
connected to these attenuated and added
frequencies would effectively duplicate
the original sound.
8 The World of Mathematics, Volume 4,
New York, 1956.
9 Baron Rayleigh, The Theory of Sound.
2 volumes, Dover Publications, New York.
1945.
AUDIO
28
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AmericanRadioHistory.Com
DECEMBER, 1964
ALTEC ALL-
TRANSISTOR
XI ANBkCY
J,z?e(J27:tl«
STEREO
AMPLIFIER
The Only All -Transistor Stereo Amplifier Backed by
6 Years
"Professionals in the recording and
broadcasting industries know that Altec
has been making solid-state amplifiers for
some time now-for professional use only.
The flTeee(d reflects the experience
Altec has achieved in making these amplifiers."
AUDIO Magazine, April, 1964
At a time when most amplifiers were of the
vacuum -tube type, we marketed our first all transistor amplifier. Then, five years later, we
presented the Three Sixty. In the past year,
it has been proved again and again by satisfied
users. Because you asked for it, we have improved the styling of the instrument, making
it more modern, good-looking, more convenient to operate.
CHECK THESE REASONS.
YOU'LL SEE WHY THE
ALTEC cWaee Cih2"lr IS SO SUPERIOR.
1/Altec's wide experience in designing solidstate circuitry for audio frequencies has given
us a lead over other companies. This experi-
of Leadership in Solid -State Circuitry!
ence made the Three Sixty possible. Over
five years ago, we designed the first all -transistor amplifier (the 351A) for high quality
applications.
We
also developed the first
successful all -transistor repeater amplifiers
for use by telephone companies. We also were
the first to combine transistors with vacuum
tubes in the famous 708A "Astro".
1/All-transistor circuitry of the Three Sixty
offers greatest possible durability because,
unlike heat -generating vacuum tube amplifiers, it always runs cool. Hence, there's no
deterioration of quality caused by heating and
cooling of vital circuit components.
P" The
Three Sixty is
a
genuine Altec
Y1ÀYBACR, Component. It is part of a line
that has won acceptance by leading recording
and broadcast studios. There's a world of
difference between equipment designed for
and used by professionals, and ordinary hi fi
components made strictly for home use.
1/You'll like the looks as well as the sound of
the Three Sixty. And, its size is smallest of
any integrated stereo amp/preamp on the
market today. The Three Sixty is priced at
$389.00; matching cabinet $11.00 extra.
In addition to those shown below, other
studio -users of Altec YIANBACIC Equipment
include: ABC, Universal Recordings, Columbia, Sam Goldwyn, Glen Glenn, United Walton,
just about every major concert hall,
auditorium and theatre in the nation, includand
ing all Cinerama Theatres. At the New York
World's Fair, some of the exhibitors who
selected Altec equipment include I.B.M., Du
Pont, Chrysler, Ford, General Electric, Heinz,
Cinerama, Billy Graham, Texas Pavilion,
Johnson's Wax, and many more.
Visit your nearest Altec Distributor (Yellow
Pages) and hear the finest equipment in the
world of sound: Altec YIANBACY. Equipment.
Be sure to ask for your courtesy copy of Altec
YIANBACK and Speech Input Equipment for
Recording and Broadcast Studios. Although
prepared specifically for the recording/broadcasting industry, the conclusions to be drawn
about your own home music center will be
obvious. Or, for free copy, write DEPT. Al2B.
Four extra -heavy heat sinks in
Altec Three Sixty make possible
continuous operation with
virtually no rise in temperature.
Internal -external heat is kept
well below industry standards
to guarantee lifetime trouble free, service -free operation.
Two power output transistors
(four per channel) on each
heat sink.
Modular preamplifiers are completely shielded from
output and power circuits to assure long life, minimum maintenance. Another Altec exclusive!
401.0.1%.e.rtfi +r ,n
The Three Sixty is used by Dave Sarser's and Skitch
Henderson's famous "Studio 3" in New York.
4
Top view of Three Sixty. All -transistor circuitry
eliminates hum and hiss common with vacuum tube
amplifiers. Features 3 automatic resetting circuit
breakers-one in main power circuit, one in each
speaker output circuit.
Plug-in facilities provide independent voltage output to drive separate remote power or booster
amplifiers (Altec all -transistor 351B) for patio, pool
side, recreation room, other remote areas.
Impedance selector switch eliminates confusion
about multiple speaker terminals.
e e
-
. f1\.'C'...
MOO
- If1
Perfect partners! Rack-mo unted Altec Three Sixty
works with Altec 314A FM Multiplex Tuner at SimO -Rama Recording Studio, N.J.
-
ALTEC LANSING
ßn/7
A[TE(® CORPORATION
77 U
L
LANSING CORPORATION
AUDIO
l
Subsidiary of
Ling-Temco-Vought, Inc.
A
ANAHEIM, CALIFORNIA
The film production service at Virginia State Department of Education relies on Three Sixty for power in
conjunction with other Altec PLAYBACK amplifiers
and controls.
Circle 119 on Reader Service Card
DECEMBER, 1964
29
www.americanradiohistory.com
AmericanRadioHistory.Com
FOR THIS MUCH MUSIC
... with Altec
Full -Size pLAYBACK Speaker Systems
ALTEC 843A "MALIBU"
contains the same speaker
components as the new
844A Monitor & VLAYBACK,
Speaker System (shown at far right)
for professional recording and
broadcast studios: a pair of low resonance Altec 414A bass speakers, a cast aluminum sectoral
horn powered by an Altec 804A high frequency driver, and a
two -section dividing network. Dimensions: 40"H, 25"W, 18"D.
Price: $356.00 in Walnut. Low -boy model-the 838A "Carmel"
-is also available.
"VOICE OF THE THEATRE"e
Speaker Systems now come
fully clothed, ready for your
home or high quality appli
cations in public places where
both styling and excellent sound are the
goal. Available as the A7W or A7 -500W
models, these are the identical PLAYBACK speakers used by
leading recording studios. Dimensions: 46" H, 30" W, 24" D.
Price: A7W Speaker System, Walnut Finish-$384.00; A7 -500W
Speaker System, Walnut Finish-$411.00.
NOTE for do-it-yourself decorators and recording engineers:
The A7 and A7-500 are available as usual in their economical
utility cabinets at $288.00 and $315.00 respectively.
ENJOY SOUND WITHOUT COMPROMISE WITH THESE NEW FULL-SIZE VIAAYBACY., SPEAKER SYSTEMS FROM ALTEC:
These new Altec PIAYBACY., speaker systems contain all of
the elements that are essential to give you no -compromise
big sound. Each is large enough to hold a low -cutoff sectoral
horn which permits the simplicity of a two-way system with
a single crossover. Use of a 90° horn provides perfectly controlled, wide angle dispersion of both the mid and high frequencies to achieve big sound. This subject of "big sound"
is fully covered by both proponents in THE GREAT
DEBATE, mentioned elsewhere in this advertisement.
Both the 843A "Malibu" and the "Voice of the Theatre"
Systems are full-size, floor -standing PLAYBACK units with
impressive cabinets in walnut. They are styled to do credit
as an impressive furniture piece in any living room. In fact,
these are loudspeakers that you can display proudly ...and
listen to by the hour.
Circle 120 on Reader Service Card
30
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AUDIO
DECEMBER, 1964
NEW FULL-SIZE YnKNBKCK SPEAKERS FROM ALTEC
NEED ABOUT 3 SQ. FT. OF FLOOR SPACE TO GIVE YOU
NO -DISTORTION MID -RANGE WITH LOWS & HIGHS TO MATCH
THE ALL-IMPORTANT MID -RANGE
Almost any good speaker has good lows
and highs because so much attention
has been given to these extremes of the
frequency spectrum in recent designs.
But very few speakers have really good
mid-frequencies. Yet, it is the mid -range
that holds the primary attention of the
recording engineer because this region
embraces 90% of all musical material.
Most fundamentals and all of the rich
lower harmonics are in this critical
range. It is the meaty part of music and
is essential for life -like reproduction.
When you judge one of the new Altec
41ANBACY.,
speaker systems through
A -B comparison listening tests, we urge
studios depend on Altec VI ANBACK,
speakers for monitoring and playback
in a continual comparison of the live
rendition to the freshly recorded version.
While listening, ask to hear a full
orchestration of many pieces performing through a wide dynamic range. This
is the acid test for good mid -range. It
will quickly expose any existence of
"mid-range muddiness"-a distortion
which has crept into many speakers of
recent design due to the attention
concentrated on highs and lows, with
little or no regard for the mid -range.
THE GREAT DEBATE ABOUT
BIG VS. LITTLE SPEAKERS
subtle, though readily dis-
cernible, difference
difference that
explains why so many major recording
course referring to "THE GREAT
DEBATE" which appeared in the
distortion mid -range. Their smooth,
no -distortion reproduction in this region
makes
a
-a
TAKE
A
1
affirmative-that a
good big speaker
is indeed much
better than the
best little speaker.
We are certain that
s tUOil LITTLE
SPEillier
if you want the
As was inevitable, the controversy about
big vs. little speakers had to be settled
sooner or later. Now, the tiresome argument is over, with expert proponents
stating the case for each side. We're of
you to especially notice their clean, no -
August issue of HiFi/Stereo Review,
titled "IS A GOOD BIG SPEAKER
BETTER THAN A GOOD LITTLE
SPEAKER?". If you haven't yet read it,
just let us know and we'll gladly send
you this reprint giving both sides.
Not surprisingly,
we were asked to
MNIU ßNi SI'M:AhF]i
speak up for the
best there is in
musical reproduction you will give up
some floor space for our good full-size
speaker systems. Write Dept. Al2.
ALTEC LANSING
A[TE(®
.119.0
CPRIPIAIJON
CORPORATION
':9A
Subsidiary
of
Ling-Temco-Vought, Inc.
ANAHEIM, CALIFORNIA
CUE FROM THE RECORDING & BROADCAST
A NO -COMPROMISE SPEAKER SYSTEM
STUDIOS: SELECT
Professionals in sound - people whose careers as performers,
directors, and recording engineers depend on the quality of their
equipment have for years relied on Altec YUMMY, equipment in their studios. In fact, in the days before the term "hi fi"
was ever coined, Altec was already producing studio -quality
PLAYBACK. components. And, as another fact, high fidelity as
we know it today was born right in those same recording, broadcast, and motion picture studios.
You can bet your bottom dollar that the studio professional
not only expects, but knows where to get sound quality that
approaches the "live':.. and no compromises tolerated. Perhaps
that's why so much of our income comes from the professional
and commercial sound industries. Here's an example of our
latest design for the professional market:
-
THE
604 "DUPLEX"
IS BACK! The
most famous single speaker in
history of high
fidelity is back,
packed with all
the new engineering knowledge that has been acquired since its original design two
decades ago. The new SUPER
"Duplex" 604E is an updated version of the original and famed 604A,
B, C, and D Models (you'll find more of these speakers still in
use in quality recording and broadcast V1vKN%KCK, and monitoring than any other speaker ever made).
The SUPER "Duplex" offers highest efficiency like all Altec
speaker systems with full capability of reproducing the entire
dynamic range of music with today's medium -power transistor
amplifiers. Also check the 604E for purity of mid -range, exceptional attack time, and no -distortion 20-22,000 cycle frequency
range. With a dual magnetic structure that weighs 26 pounds,
13 ounces, the SUPER "Duplex" 604E is the most efficient
speaker offered to the home music market. Price: $199.00
including two -section dividing network.
For optimum performance, we recommend the "Malibu"
furniture -styled enclosure for the SUPER "Duplex". It is available as the 855A Cabinet and comes with pre-cut baffle for
easy installation. The 855A is priced at $126.00 and is also
recommended for use with any other 15" Altec speaker.
AUDIO
NEW! SPECIFICALLY FOR RECORDING & BROADCAST USE.
STUDIO VERSION OF THE "MALIBU" & "CARMEL" - Designed
especially for recording and broadcast studios, the 844A Monitor
& 41ANBACK. Speaker System contains the same speaker components as the 843A "Malibu" and 838A "Carmel". Comes in
studio grey cabinet with sectoral horn mounted below the low
frequency speakers so that the unit may be mounted above the
observation window in studio control rooms. Dimensions: 24" H,
31" W, 16"
D.
Price: $327.00.
Circle 121 on Reader Service Card
DECEMBER, 1964
31
www.americanradiohistory.com
AmericanRadioHistory.Com
PEA K
T
AMPLITUDE
METER
IME
CONTROL
1/8 SEC.
AND
COUNTER
BAND PASS
AVERAGE
AMPLITUDE
FILTERS
METER
SET OF 14
AMPLIFIER
The Conn and Allen organs also depend to an extent on additive techniques.
The electrical addition at frequencies is
accomplished by well designed mechanical switches, which are quite similar to
telephone crossbars. Figure 10 shows a
for
peak
Fig. 6. Circuit
measuring
CONDENSER
and
TRANSMITTER
average
power.
AVERAGE
AMPLITUDE
CONTROL
METER
15 SEC.
TIME
Conn switch.
Such techniques are extremely useful
in generating flute sounds whose waveforms simulate sine waves. The clarinet
and stopped organ pipe sounds which
sound hollow and woody contain a minimum of even harmonics. When these
stops are required, the switching mechanisms do not pick up the even harmonics.
Filters
The passage of an alternating electric
current through a long line or cable is
r-
40
40
t
r
(A)
20
4
rITUITT 111
R
5
24
20
15
HARMONIC NUMBER
o
1/440
THIRD HARMONIC VALUE 2
FUNDAMENTAL VALUE 4
-º0
.-1/440 SEC
(B)
60
500
1000
1000
3000
2500
2000
FREQUENCY-cps
(C)
f=125 cps
o
Fig. 7. Formant effects on tone spec-
trum. (Baldwin Piano Co.)
if
FLUTE 007400000
"A" 440
i
1000
1500
2000
3000
2500
60
f=500 cps
40
T1
o
1000
500
MOO
2000
Ufv\H\jAv
(D)
0500
STRING 001455555 "A" 440
3500
3000
=1000 cps
Fig. 9. Oscillograms demonstrating Ham20
0
mond tone addition.
(E)
1000
500
1500
3500
2000
5000
FREQUENCY-cps
If we were bold experimenters, we
might try changing the relative worth of
the harmonics and we might even add
the 7th of the fundamental or the 5th
of the 3rd harmonic. The Hammond
organ is built on this principle. The
drawbars are potentiometers which control the attentuation of the appropriate
harmonics and partials. Figure 9 shows
graphically the frequency addition that
takes place in the Hammond circuit.
The Hammond scheme provides the
musician with great flexibility. However,
one might like to have the formants or
harmonic patterns preset by internal
wiring so that engaging a key 'would
pick up the entire harmonic pattern.
These we would call stops.
STRING
REED
FLUTE
40
40
30
30
30
º0
º0
20
10
I0
40
-0
±
>
Ú
5
5
1
º
4
5
!
10
12
10
o
4
5
HARMONIC NUMBER
Fig. 8. Spectra of various instruments. (Baldwin Piano Co.)
10
Iº
usually accompanied by waveform distortion. This effect is particularly noticeable in the transmission of complex
waveforms. Heaviside showed that this
distortion was due to the distributed electrical capacitance of the line filtering
out certain components of frequency
from the wave during transmission.
In 1924, G. A. Campbell at Bell Laboratories extended Heaviside's theory
and showed how it was possible in practice to distribute inductance and capacitance in electrical transmission lines so
that certain selected ranges of frequency
are transmitted with negligible attenuation, while other frequencies are suppressed almost entirely.
In the simple form of the theory, the
transmission line is regarded as a repeated network or chain of impedances
arranged in series and in shunt. From
this we derive the low-pass, high-pass,
and band-pass filters needed in elecAUDIO
32
www.americanradiohistory.com
AmericanRadioHistory.Com
DECEMBER, 1964
.....
Meet the new Royal Grenadier
world's most
perfect speaker system. Pretty soon every stereo
system 'round will be featuring this revolutionary divergent lens speaker system. The first loudspeaker
ever designed and engineered for stereophonic reproduction. Lets you sit anywhere hear everything.
-
EMPI RE
Circle No. 109 on Reader Service Card.
www.americanradiohistory.com
AmericanRadioHistory.Com
As Featured At The World's Fair Pavilion of American Interiors
The New Empire Royal Grenadier
Divergent Lens Speaker System-Model 9000M
Model 9000M
1.
outstanding features:
2.
3.
4.
Years ahead in design and engineering the Grenadier projects a majestic sound
unlike any you've heard before. Its cylindrical shape creates a system relatively
free from room standing waves and approaches acoustically flat frequency response.
Sound level and tone remain constant virtually anywhere in the room. Its three
divergent acoustic lenses achieve unparalleled stereo separation. With the Empire
speaker placement becomes non -critical.
Grenadier
5.
6.
7.
8.
9.
10.
11.
...
12.
Ba... Mid. High.
15" mass loaded woofer with floating
suspension and 4" voice coil.
Sound absorbent rear loading.
Die-cast mid frequency -high frequency
full dispersion acoustic lens.
Hand rubbed satin walnut finish.
Imported Italian Perlata marble.
Ultra -sonic domed tweeter.
Full presence mid range direct radiator.
Exclusive non -resonant rigidized
heptagonal sonic column.
World's largest (18 lbs.) speaker
ceramic magnet structure.
Front,oaded Horn -360° aperture throat.
Complete symmetry of design with
terminals concealed underneath.
Dimensions: height 29"
diameter 22".
-
.
WALK AROUND
Try this simple test.
will notice no change in sound
level of bass, mid range, and highs. Full
frequency and separation is assured by
Empire's exclusive divergent acoustic
lens system.
You
...
mal..
Empire Grenadier model 8000
Started a new era in speaker systems.
Measures 29" high with a 151/4" diameter. Its features are virtually the same
as the 9000 plus the exclusive Empire
Dynamic Bass Reflex
high Q reflex
tuned columns for in -phase low frequency reinforcement. The scientifically accurate gradients and vented
...
ports provide unbelievably enriched
Try this same test with any other brand
of speaker. Some speakers will only
have a narrow angle of high frequency
sound propagation. Some may have 2
or even 3 bands of high frequency
sound. With these or other speakers,
slight shifts of position, turning one's
head, or even leaning to one side may
cause sharp changes in the listening
tone and level. Not so with the Empire
Grenadier.
Acoustically engineered to let you sit anywhere
Grenadier is decorator -designed to fit any decor
modern .. fit in corners or against walls.
-
...
hear everything. The Empire
from warm elegance to stark
.
Its satin walnut finish is designed to blend with all furnishings. An imported Italian
Perlata marble top is optional for added elegance on the model 9000. The Empire
Grenadier is a truly beautiful and functional achievement in sight and sound.
base response.
For a sound demonstration of the
Empire family of "most perfect"
products, go 'round to your dealer or
write for complete literature.
Empire 880P and 880PE Elliptical Cartridge
The model 498
E.
EMPI RE
'World's Most Perfect High Fidelity Components"
Empire Scientific Corp.
- 845 Stewart Ave.,
"...truly excel...the finest cartridge tested."
Audio Magazine stated
- tailor-made for console or equipment cabinets ... the famous
398-outstanding-too
handsomely fiflished to hide behind cabinet doors.
precision engineered product of the
High Fidelity reports on the Troubador:
one of the finest, handsomest record players available."
highest quality
Empire
...
"...
Garden City, L. I., N. Y. Export: EMEC, Plainview, L. I., N.
Y.
Circle No. 108 on Reader Servize Card.
www.americanradiohistory.com
AmericanRadioHistory.Com
- Canada,
lent
Frequency response 8 to 30,000 cps.
Compliance 20X 10-6cm/dyne. Empire
880pe comes with a biradial elliptical
hand polished .2 X.9 mil diamond.
Empire Scientific Corp., Ltd., 1476 Eglington West, Toronto
Fig. 10. Keyboard
assembly. Left end
of Great Manual.
manufacturers utilize both within one
instrument; the Allen Sheraton Model,
the Schober Concert Model. The organ
using sine wave additive technique must
also include circuits for differentiating
and shaping the sine wave in order to
get rich harmonics which are too numerous to obtain by addition. Organs depending on sawtooth waveforms as the
basic wave shape must have additional
circuits for obtaining a sine wave from
a sawtooth in order to generate flute
tones. This is done through integrating
circuits.
tronic organs. A rigorous proof for
filter theory and m -derived filters is
given in "Communication Engineering."' o
We have been discussing two seeming-
ly unrelated subjects, the first was harmonic analysis and the second filter
design. Whether the energy distribution
is determined from the Fourier coefficients (either numerical or mechanical
integration) or by direct measurement
it is possible to draw the "frequency
output curve." Let us design a filter
whose frequency response curve is identical to this frequency output curve (the
formant)
Since the filter is made up of resistors,
capacitors and inductors, we should be
able to change these at will. We can do
this analytically or we can actually
twiddle dials or solder different components into this circuit.
Now we will impress the output of a
sawtooth oscillator upon this filter. As
we turn dials, our variable filter may
convert the harmonic -rich sawtooth to
unpleasant sounds. Some of our experiments may generate sounds more pleasant than the original.
So, while the first approach to electronic organ sounding may be duplicate
air-organ sounds, the consequence of
our research has been to free us to generate air-organ -like sounds which are
beyond the bounds of air-organ design.
There are other classes of organ tone
color which require special filtering since
they depend on harmonic suppression.
They are the diapason family, and
"stopped" tone colors. Both of these
classes have alternately prominent harmonics rather than groups of strong
adjacent harmonics. The even harmonics,
especially the second, are more prominent in diapason tone. These harmonics
are omitted in additive -design organs.
In filter type organs, the removal of
alternate harmonics requires ingenuity.
.
win and Schober, production of these
tone color classes is accomplished by
addition and subtraction of the proper
amount of complex wave of twice fundamental frequency. Figure 11. shows the
principle of subtraction (adding out of
phase) which is used for stopped tone
colors. The spectrum of waveform A
containing a complete series of harmonies is compared to that of a waveform A + B where B has twice the f requeney of A, half the amplitude and
opposite phase. Spectrum A + B has the
even harmonics missing.
Electronic organs using fixed -frequency tone generators are divided into
two classes formant, and tone synthesizing. We can now see that there are
merits to both designs. Some organ
:
color can be effected.
We see now that some instruments
such as Hammond do not try to "imitate" air -organ sounds; the second group
such as Baldwin, Conn, Allen, Wurlitzer,
Gulbronsen and others provide tones
which are analogs to air -organ sound. In
addition, these organs have sounds which
their designers consider to be improve (Continued on page 68)
(A) SPECTRUM COMPARISON
A+
Fig.
11.
Use
40
20
2
of
out -of -phase signals to synthesize
desired
40
wave
o
4
form. (Baldwin Piano Co.)
0
ETC.
0
2
B
4
i
e
lo
ETC.
HARMONIC NUMBER
(B) OUT OF PHASE SIGNALS
INDIVIDUAL
WAVES
A+B
In electronic organs such as the Bald SUM
lo W. L. Everitt, Communication Engineering, McGraw-Hill, New York, 1937.
AUDIO
It is a matter of personal taste when
comparing the synthesizing techniques
of the Hammond or some Allen instruments to filtering techniques of a Baldwin or Conn organ. The filter organ provides an array of filters which can be
shunt simply and directly to the inputs
of the preamplifiers.
In tone synthesis, complex switching
arrangements are required to pick up
the appropriate harmonics coming from
many tone generators. Frequently, the
harmonics must be appropriately attenuated in order that the proper tone
DECEMBER, 1964
35
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Some plain talk from Kodak about tape:
physical testing and
tape performance
The High Speed Tensile Tester is designed to break tape
under load ... and gather a lot of useful data besides.
Magnetic tape
is
subject-day-in,
day-out-to a wide variety
of
stresses and strains. That's why we
are more than casually interested
in its tensile properties. Tape is
much like a rubber band. Put under tension, it will stretch. When
the tension is released, it will snap
back to its original shape. It will,
that is, unless you've stretched it
beyond its yield point. For if over
a certain amount of longitudinal
stress has been placed on a tape,
the tape will lose its ability to
recover and will, in fact, remain
permanently elongated. Stretch
it even further and, naturally, the
tape will break.
Deformed tape will not reproduce sound faithfully. And tape
that breaks too easily is just a
plain nuisance. So we set our
sights high and developed a special triacetate-called Durol base
-that's exceptionally tough, yet
breaks clean without "necking
down." In order to prove its worth
and keep it that way, we developed a
tight set of specs for our quality control boys-specs which were a
direct outgrowth of the conditions
under which a tape is to be used.
For example, the shock of going
from fast wind to fast rewind. Or
the shock generated on a running
recorder when the supply spool
jams.
We think that tape should be
able to take this sort of punishment
routinely. So, of course, we double,
triple, even quadruple the requirements! And just to make sure that
the tape performs we build torture tests that would have delighted Attila the Hun.
Here is one tester that is outstanding in its fiendishness. It's
called the High Speed Tensile
Tester and is designed to break
tape under load.
But like any good one-man
band, it does a lot more than just
one job. It not only breaks tape
but gathers scads of very useful
data as well-data which completely describes a tape's tensile
properties. Here's how it works.
It's built like a tape deck with the
tape attached to one half of a
split -ring electrical strain gauge.
We run the deck and then jam on
the brakes on the supply reel but
keep the take-up reel going. The
strain gauge takes the full load
and the split ring spreads and deforms. This deformation causes
the gauge to change resistance
and causes the DC voltage on it
to pulse. We monitor the pulse on
a scope and measure the duration.
This gives us a figure of merit in
terms of tensile strength.
Just how good is Durol base?
Well, consider this data. Yield
strength for Durol base is 47%
greater than regular triacetate and
70% greater than diacetate (the
two most common plastic support.
materials). Break strength is 43%
greater than triacetate and 80%
greater than diacetate. And this
is the kind of test that almost
duplicates actual use conditions
on your tape equipment.
But any torture test one engineer can devise, another engineer
can improve upon. Take the
Toughness Tester, for example.
This is an instrument designed to
determine a tape's strength (toughness) by measuring the force required to break a sample. A.
measured length of tape is held securely between two clamps. Then
it is struck and broken by a falling pendulum. Because it has
been raised to a fixed height, the
AUDIO
36
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DECEMBER, 1964
MA-A21
TRADEMARK
pendulum always delivers a precise and repeatable amount of
impact. The energy absorbed by
the tape at impact controls the
height of the pendulum's back swing. Thus, a measurement of
backswing height
is a
direct
measurement of toughness. The
strain rate that this device imposes is on the order of magnitude of 200,000% per minuteenough to break any acetate based tape. How does Durol base
compare to conventional acetates? Well, it comes through
this test, too, like an Olympic
star. In test after test, Durol base
SOUND RECORDING TAPE
proves to be about 40%
stronger. This toughness test also
provides a valuable measure of
permanent elongation. Durol
base's unique "shear-pin" action
lets it break clean
with minimum
elongation
(less than 1%
compared to 10%
for other acetates). These
are only two of the more interesting physical tests routinely
performed on random samples of
Kodak tape. There are dozens
more, of course. And we haven't
even gotten into electronic testing
yet. But we'll save those for
anther day.
Choose KODAK Sound Recording Tape, Type 31 A, for all general-purpose and low -print applications. Or Type 34A whenever
you need high -output or low -noise
characteristics. For extended play-
ND RECORDING
ing times try our extra or double play tapes .
or try the new
triple -play tape, so thin you get
3600 feet on a 7 -inch reel. KODAK
.
.
TAPE
Sound Recording Tapes are available at electronic supply stores,
camera shops, specialty shops, department stores
everywhere.
...
EASTMAN KODAK COMPANY
Rochester, N.Y.
Circle 122 on Reader Service Card
AUDIO
DECEMBER, 1964
37
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A Basic Course in
Commercial Sound
NO
H.
Chaer
Output Matching.
A few minor points need
clearing up that were crowded
out of the last installment. The
broad principle of output matching was covered in Chapter 5. A
feature that can be helpful is
the provision of multiple output
taps on the amplifier. Smaller
amplifiers, up to say 25 or 50
watts, will provide the same
kind of output taps usually
found on a high fidelity amplifier, 4, 8 and 16 ohms. This
facilitates connecting various
numbers of 16 -ohm speakers directly.
Larger amplifiers are designed for constant-voltage line
operation. Theoretically, they
only need one output pair, to
provide the needed 70 volts
nominal, at an impedance to
correspond with the power rating. But it is an asset, especially
in portable systems, to have
extra tappings for other voltages, particularly lower ones, so
the amplifier can have optimum
power output where the total
rating of connected speakers
and that of the amplifier do not
happen to agree as conveniently
as may be expected.
Provision of multiple taps
also facilitates varying the power delivered to individual speakers in different locations. However, this increases the demand
on wiring (Fig. 9-1). A more
direct way to make such adjustment possible is by means of
multiple tapped -line transform -
70
50
0
50
70
FULL
POWER
HALF
POWER
I
RATING/
\RATING
Fig. 9-1. Using different amplifier taps on
constant -voltage line type output as bus
connectors for varying feed to different
speakers, or groups of speakers.
ers. These are available from
several manufacturers nowadays. However, changing the
amplifier tap is a convenient
way of varying the relative power sent to whole lines of speakers.
Stereo Installations.
Sometimes the customer will
question whether stereo is feasible, because he fancies the
notion. At other times, the provision of stereo may be advisable, to achieve something that
would be more difficult monophonically. The questions to be
answered in deciding on a
method of achieving the desired
end in either case are similar.
To be effective, stereo must
achieve its objective, of providing separate "sources" for different parts of the composite
sound presented, otherwise it
may only add to confusion bad
enough already, in mono
How is the stereo effect
!
achieved? By intensity differences between channels (or between separate sound sources)
or by time differences between
them? Or is it by a combination
of both intensity and time differences? If so, which is more important in the evolving of a satisfactory system'?
The fact is that both contribute, at different component frequencies, and also (which is not
always realised) according to
environmental circumstances. In
a small room, with little reverberation, intensity differences
can never be very great from
point to point, so human hearing
becomes acutely sensitive to
minute time differences in this
environment, particularly at
lower frequencies (below about
1000 cps) . At higher frequencies
(above about 2000 cps) the obstacle effect of the human head
creates an intensity difference,
to which the hearing faculty
pays more attention, because
time is indeterminate when such
small waves are involved.
In larger rooms, reverberation becomes more dominant,
whether we want it to or not.
We may be using stereo, in effect, to reduce the apparent
effect of reverberation, but still
its presence will change the sensitive factors on which hearing
relies. To ignore reverberation
in interpreting sound heard, the
hearing faculty now pays more
attention to the leading edges of
sound wave patterns, and much
less to the sustained "follow
AUDIO
38
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DECEMBER, 1964
through" tones. But variation
of distance, due to different
audience locations relative to
speakers for the separate channels, can interfere badly with
intended timing effects. So the
important thing will usually be
to control relative loudness from
the respective channels, so that
the desired channel is only heard
from the desired side.
In a long hall, the method is
simple : feed left channel down
the left side and right channel
down the right side (Fig. 9-2).
Whether stereo presentation is
better than delay treatment of
monophonic program for this
kind of situation depends on
both the type of hall (its reverberation characteristics) and on
the type of program. Stereo can
seldom do very much for presentation of a single speech. For
discussions it is much more helpful. It helps the audience identify who is speaking and, if more
than one person speaks at a
time, it helps the audience resolve the confusion of sound this
tends to create.
Stereo may also be desired for
the presentation of musical en-
tertainment, either from records'
or from live performance.
Again, the left -right method
would be good for the long hall.
But what about rooms that
either spread out the wrong
way, or are of more complicated
shaper Then it requires careful
thought about what will be the
best way to achieve the objec-
LEFT SPEAKERS
0000
RIGHT SPEAKERS
Fig. 9-2. A long narrow hall is simple for
stereo installation.
0 0 0 O
0 0 0 0
0 O O O
Fig. 9-3. Ceiling plan for connections to
get a form of stereo in a large, spread out floor arrangement with low ceiling,
such as a restaurant.
CEILING
/0 0
CEILING
Fig. 9-4. Modification to the ceiling,
where proper sound location is needed
in a large -floor, low -ceiling installation.
tive.
In a large, spread -out area,
such as a restaurant, especially
if this has a fairly low ceiling,
the best way may be to install
speakers as uniformly as possible throughout the ceiling surface. With mono, this creates
no particular problem of connection: they all radiate at low
level and the audience is often
unaware of any sense of
"source"; sound just fills the
room pleasantly. But to get
stereo, so all the audience can
appreciate it, requires that alternate speakers be connected to
AUDIO
the other is "right" (Fig. 9-3).
Such an arrangement may
provide good separation, but it
is no good if specific identification of source direction is required. For music, this means
one cannot present the type of
demonstration which says, "the
violins are now playing from the
right," because they may appear to be to the right for some
listeners and to the left for
others. Also it cannot be used
for live relay, because the natural association, based on positions visually observed, will be
violated by the sound at some
listening locations.
One method of overcoming
this is to direct sound by some
means, so each speaker can only
be heard from the side for which
it is intended (Fig. 9-4). In a
large arena, the same kind of
treatment will usually be desirable (Fig. 9-5). Note that baffles
or barriers in this usage need
not act as observers. The system
will be more efficient if they
work as reflectors.
A particular kind of installation where the term stereo is
often abused occurs with juke
boxes. Most of the juke box
chains now make available machines to play the new stereo
discs. The average installer
tends to put the speakers at opposite ends of the establishment,
which may well be so far apart
that few listeners stand any
chance of hearing both speakers
at once (Fig. 9-6). A listener
nearer either speaker will only
hear that speaker, while a listener nearer the middle will
hear more of local conversation
and gossip than of the juke box
stereo
Restaurants are not the easiest places to locate- speakers in,
at the best of times. But to get
true stereo they are most often
next to impossible. However, a
proprietor likes to know he's
getting what he's paid for. If the
juke box concessionaire has sold
him a stereo system, he's disconcerted to have a local stereo
enthusiast come in and tell him
!
AUDIENCE AREA
Fig. 9-5. Using pairs of projector horns
in an arena installation to achieve stereo
illusion.
alternate channels, so that,
whatever pair of speakers an individual listener may happen to
be between, one is
"left" and
DECEMBER, 1964
39
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This famous
brand
vacuum tube
stereo receiver
is $3895°
This famous
brand
vacuum tube
stereo receiver
is $39995
This famous
brandy'
vacuum tube
stereo receiver
is $449E'
*names on request
www.americanradiohistory.com
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STERE
CE F
But... th last word
in stereo receivers
is ogen
soli state.
The new RT6000
is $39995
According to the audio experts, the RT6000 shouldn't exist.
Not at $399.95. Not for the kind of performance it delivers.
Whether compared to vacuum tube or solid state receivers, the FM -Stereo 60-watt RT6000,
is the "dream receiver" come to life. Solid state power for precisely defined, truly transparent
sound; unlimited control versatility; response above and beyond audibility; extreme FM sensitivity; reliability-on every standard, a consummate professional. And only Bogen-with its
ten-year head -start in solid state technology-could have produced it at such moderate cost.
Even costlier solid state receivers still use tubes (unadvertised, of course)-usually, in the
RF stage. But Bogen has achieved the full potential of solid state. The RT6000 does not have
a single tube to age, cause hum, noise or distortion; nor any output transformers to impair
response. Listen and compare. See if the RT6000 doesn't produce the tightest, cleanest bass,
highs and transients you have ever heard!
The RT6000 also has the 'extras' you want. Private stereo headphone reception, tape
monitoring, professional tuning meter-even automatic FM -stereo switching circuitry!
Want to know more? Visit your dealer and ask for a demonstration. For complete specifications and the new Bogen catalog, write: Bcgen, Dept. C-12, Paramus, N. J.
BOGEN
COMMUNICATIONS [DIVISION
LEAR SIEGLER, INC.
PARAMUS, NEµ' JERSEY
Circle 123 on Reader Service Card
www.americanradiohistory.com
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stand what he heard, while with
your system it sounds horrible
The tone control will help
minimize the unwanted exagFig. 9-6. A poor
gerations, so the acoustics still
installation some- seem about what they should be,
times encountered
while the audience can now hear
in diners and restaurants that are better. This takes skillful and
supposed to have painstaking setting up, but once
"stereo"!
the controls have been set to suit
the acoustics of the particular
church, they will not need much
changing.
If you have much of this class
ducive to the building up of of work, it may be worth while
larger congregations than im- to set up a fairly comprehensive
pressive religious music. Small and elaborate tone control syschoirs in large churches always tem, which can be used to optiseem somewhat inadequate. A mize response and then, from it,
public address system, with pro- design a less elaborate compenvision for phono or tape, can sation circuit that will achieve
enable the humblest church to the same result, with provision
present the best selections of for a little variation, using a
religious music in stereo, which much simpler control circuit.
can be a wonderful experience,
if the system handles it well.
Here again, the planar speak- Installation Headaches.
er is a useful adjunct, if the
We've covered most of the
acoustics permit. In larger
things
that can cause headaches
churches, column type units may
in
installations
: wrong impedbe necessary to avoid feedback
ance
level,
or
poor matching,
when the system is used with
and
so
a bad conon.
Sometimes
mikes, either for the sermon or
nection
cause
that
can
difficulties
for a live choir. For a live choir,
time
to
But
most
of
take
trace.
directional mikes are a must, berelatively
those
things
are
obcause long range pickup with a
bad feedback problem means vious. The one headache that
omnidirectional types are vir- stands out as a real nuisance is
when unexpected hum appears.
tually useless.
A good comprehensive tone We'11 assume you've checked
control is also essential, because each item of equipment and
of the highly colored acoustic found it performs without unproperties inherent in most due him. Then when you've got
churches. Working a sound sys- the system all connected up,
tem close to feedback point, or there it is : a snorting hum, fit
even quite a little below it, will to kill The only thing that
exaggerate these acoustic de- seems to stop it is switching off
ficiencies, so that what previ- the system-admittedly not a
ously appeared to be character- practical remedy
Assuming it is not an ordiistically the tone of a church
nary
input hum, due to un("cathedral quality"), becomes
shielded
leads, or mike leads
something almost unbearably
taken
over
a bad route-which
grotesque. Unfortunately, you
is
easy
to
verify
by turning the
cannot `blame' this on the
gain
down
zero,
to
which will
acoustics, because the layman is
cut
out
picked
up
hum
at the innot equipped to understand your
trouble
most
puts-your
likely
quite correct explanation. All he
in
arises
the
system's
ground
knows is that he liked the sound
without your system, except that connections. It's either "not
(Continued on page 56)
sometimes he couldn't under!
it doesn't sound in the least like
stereo So what can he do, he
asks you?
On this it is difficult to formulate any fixed rules or suggestions. Every installation will
pose different arrangements of
the same or similar problems.
The only thing to do is to walk
around the area to be served
and try to judge how much of it
can reasonably be served with
pairs of speakers so that a satisfactory stereo illusion is obtained. Probably a useful device
here, if it can be used, is the
planar type speaker, in which
the diaphragm is flat and larger
than the usual cone speaker, and
the speaker can be placed edgeon, out in the audience area.
With this arrangement, each
speaker creates a sound field
around it, whose intensity does
not appear to originate from the
unit itself, except maybe at a
distance. Uniform low-level distribution is possible, without
sound becoming inaudible at
greater distances, and the combined fields work together to
give good stereo illusion almost
throughout the room. Suitable
choice of complementary positions for the stereo units can result in a very satisfactory system. A good way to provide
locations is the construction or
suitable placement of decorative
dividers of the open type.
!
Church Choirs.
Here is another opportunity,
that many clergymen will appreciate. Nothing is more con -
!
!
AUDIO
42
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DECEMBER, 1964
An even more
"dangerous" loudspeaker
...with the world's largest
elliptical woofer!
THE EMI 901 CONSOLE
This new EMI console Model 901 loudspeaker system
to provide
designed with one purpose in mind
professional studio sound in a cabinet suitable for the
home. The 19" x 14" elliptical loudspeaker has a low,.
low bass and a particularly smooth mid -frequency response so essential to any good high fidelity system.
The four high -frequency units mounted within the
center of the elliptical woofer are designed to give a
comparable high quality finish to the bass and midrange
sections. The high frequency units at either end have a
reduced sensitivity to those in the center ... to improve,
the polar horizontal response and limit the polar verti-
...
is
cal response. Cast alloy chassis have been used to give a
resonance -free response.
All this is required of professional studio sound and
this is precisely what you get in the new EMI 901. The
hand -rubbed, oiled walnut cabinet is well -constructed
and mounted on concealed casters for easy room placement. It measures 34" high, 28" wide and 193/4" deep
and features EMI's exclusive woven metal grille for superior dispersion of sound. Listen to the new EMI 901
and get professional studio
console at your dealer
sound for just $395.00* or $285.00* without the cabinet,
for custom installation.
EMI
...
'Al! prices slightly higher
in South, West and Canada.
(Makers of the Dangerous Loudspeakers)
SCOPE ELECTRONICS CORPORATION
235 East 42nd
Street, New York, N. Y. 10017
298 Bridgeland Avenue, Toronto 19, Ontario.
Distributed in Canada by: Hartone Electronics Industries, Ltd.,
Circle 124 on Reader Service Card
AUDIO
43
DECEMBER, 1964
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The "Dynagroove" System
HARRY
In Two
An arrangement similar to Fig. 5 was
used to carry out the project outlined
above. The small room was similar in all
respects to the typical living room in
the home. As a result of the subjective
experiments, a Dynamic Spectrum
Equalizer was developed, which, in the
broadest terms, translates the sonic
equalities of the original performance
into stimuli which will project that performance into the perception of the home
listener with the greatest possible proficiency. A block diagram of the Dynamic
Spectrum Equalizer is shown in Fig. 13.
The system operates in a continuous
manner to change the response frequency
characteristic as a function of the amplitude. Typical response frequency characteristics for various levels are shown in
Fig. 14. There is a continuous variation
in response from one level to another
level. The response frequency characteristics are varied for different types of
musical selections. In effect, when the
levels are low, the low -frequency components are accentuated. For medium
levels there are slight accentuations in
the low -frequency region and the presence region of 2000 to 6000 cps and a
reduction in response in the region from
400 to 1000 cps. For high sound levels
there is accentuation in response in the
presence region and a reduction in the
frequency range below 1000 cps. When
the sound level of the program is low the
objective is to raise the sound level of the
appropriate frequency regions so that
the music can be appreciated under the
ambient noise and surround conditions of
the average residence. When the sound
level of the program is high, the level of
the presence region is raised and the
level of the low -frequency range is lowered. The procedure does not upset the
dynamic balance but rather enhances this
aspect of sound reproduction in a small
room.
The Dynamic Spectrum Equalizer
provides a dynamic alteration of the projection qualities of sound so that under
conditions of playback, which differ
from those in which the music was performed, the best perception of the qualities of the original performance is obtained. The soft passages of the music
*
RCA
Jersey.
Laboratories,
Princeton,
New
F.
OLSON
Parts-Part Two
SNOHd NI 13A31 SS3N0001
021
001
09
09
OP
OZ
010.0
r0
01
001
0001
Fig. 12. The relationship between loudness in sones and the loudness in phons.
INPUT
VARIABLE
RESPONSE
FREQUENCY
GATE
OUTPUT
AMPLIFIER
AMPLITUDE
SENSOR
Fig. 13. Schematic block diagram of the
Dynamic Spectrum Equalizer.
10
100DB
o
10
10
m
0
10
2
10
1n
0
zo
a
85DB
70 DB
w
55
10
DB
o
10
20
40DB
.10
20
Recording Overload Indicator21
The Recording Overload Indicator was
designed to provide indications of the
maximum allowable signal which can be
applied in the cutting of the master
stereophonic disc record. A schematic
block diagram of the recording overload
indicator for one channel is shown in
Fig. 15. The recording overload indicator is provided with two separate indicating meters in each of the two
stereophonic channels. One meter is calibrated to show the occurrence of program peaks which will cause curvature
overloading22 which occurs in the high frequency range. This is accomplished
by the use of a differentiator and meter
which indicates curvature overload. The
other meter is calibrated to show displacement overloading which occurs in
the low -frequency range. This is accomplished by the use of an integrator
which indicates amplitude overload.
A recording console has been designed
for recording the submaster magnetic
,10
o:
change in volume is immediately apparent. The loudest sections of the music are projected with extreme intensity. The full realization of this dynamic
range, which gives music its dramatic
impulse and its sonic structure, is perceived by the listener in his home surroundings with unique impact and intense realism.
40
100
400
1000 4000 10000 20000
FREQUENCY N CYCLES PER SECOND
Fig. 14. Response frequency characteristics of the Dynamic Spectrum Equalizer
for various sound level of the program.
are given full body and minute detail
plus a breadth and expansion which offers the listener a complete appreciation
of softness. Throughout the full dynamic
range of the performance the music
grows in structure and sonority and the
change in harmonic content which is so
characteristic of every instrument with
44
tape from the master magnetic tape.
The submaster recording console contains
the Dynamic Spectrum Equalizer and
employs the Recording Overload Indicator as well as the auxiliary control
equipment for producing the submaster
magnetic tape.
The audio monitoring of the recording
of the submaster magnetic tape is carried out in a room with dimensions and
acoustics similar to those of a typical
living room. A sound level meter is used
to check the level of the reproduced
sound.
21 The Recording Overload Indicator was
developed by R. W. George, J. G. Woodward and E. C. Fox.
22 L.
W. Septmeyer, "A Curvature
Meter for Use in Disk Recording," Journal of the Acoustical Society of America,
Vol. 19, No. 1, p. 161, 1947.
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
DECEMBER, 1964
Mr. Saul Marantz
discusses his revolutionary new
model 10-B FM Stereo Tuner
Marantz, your new 10-B tuner is
quite revolutionary. Do you feel it will
obsolete all other tuners?
Mr. Marantz: In one sense, yes. The performance of this tuner is so dramatically
superior to conventional tuners that
anyone who wants or needs perfect FM
reception today has no choice but to use
the model 10-B. Its superiority, however,
does not necessarily obsolete conventional tuners. Rolls Royce, of course,
makes superior cars, but they haven't
obsoleted Chevrolets.
Q. Is this superior performance discernible to the average listener?
Mr. Marantz: Very much so. The difference is quite dramatic. As you know,
conventional tuners have never been
able to pick up and reproduce broadcasts
which could match the quality of a fine
disc or tape playback system. This has
often been blamed on broadcasting quality. But the new 10-B disproves this theory. It reproduces the broadcast of a
disc or a tape with the same clarity and
separation as if played through a playback system proving that broadcast
quality is generally excellent.
Q. Is this true with weak broadcast signals also?
Mr. Marantz: Yes. In fact the model
10-B will reach 55 db quieting at only 3
microvolts! This is better than most conventional tuners will reach at 1000
microvolts. With a 25 microvolts station
the Model 10-B reaches a phenomenal 70
db quieting which is about 20 db better
Q. Mr.
-
than most conventional tuners can
achieve at any signal strength. This
means that with the Model 10-B there
will be excellent reception even in fringe
areas, particularly so because of the tuner's high sensitivity, its extremely sharp
selectivity and reduced susceptibility to
multipath effects, which on other tuners
cause distortion.
ode mixer
-a
technique used in modern
sensitive radar designs to eliminate a
major source of noise, harmonic distor-
tion and other spurious interference.
The whole RF circuit is balanced -tuned,
using a precision tuning capacitor with
four double sections, for further reduction of spurious images.
For the critical IF strip, we've developed the first commercial application of
the "Butterworth," or phase -linear filter. This new concept provides a number
of distinct characteristics essential for
good results. The passband, for example,
is phase -linear for extremely low distortion especially' at high frequencies
and it remains essentially phase-linear
at all signal levels.
Cutoff slopes beyond the passband are
extremely steep, allowing unprecedented
selectivity; it is much less subject to the
effects of multipath, and it doesn't require realignment with tube changes or
aging. The old standby coupled IF circuits currently in use do not have any of
these characteristics.
Q. Are there any innovations designed
specifically for multiplex?
Mr. Marantz: Yes. For multiplex reception we've developed our own unique
-
-
JA
IF Passband retains
phase linearity and sharp
slopes at any signal
strength for low distortion, sharp selectivity.
variation of stereo demodulator, which
permits phase correction to maintain a
very advanced order of stereo separation throughout the whole audio band.
Q. What is the purpose of the tuning and
multipath indicator?
Mr. Marantz: This oscilloscope device is
so versatile its single trace tells many
easily understood stories. It shows when
a station is tuned exactly to the center
of the passband. The height of the pattern shows the signal strength. The indicator shows how much multipath is
present, making it easy to adjust the
antenna for best reception. It shows if
the station is creating distortion by overmodulating. Also, technically informed
users can check stereo separation of
transmissions, discs and other sources.
Q. And how soon will the model 10-B be
available in quantities?
Mr. Marantz: The Model 10-B is a laboratory instrument of extremely high
quality which will never be mass produced in the usual sense. However, production has been stepped up fourfold and
all back-orders are now being filled by
Marantz franchised dealers.
MARANTZ MULTI PATH/TUNING INDICATOR
Conventional mutuallycoupled IF circuits
change characteristics
drastically depending on
signal strength.
Station tuning is simply
and accurately adjusted
by centering the trace.
Multipath (Ghosts) shows
up as 'wiggles' on the
tuning trace. Antenna is
simply rotated until trace
is smooth.
Q. How are such improvements accom-
plished?
Mr. Marantz: The answer to that question is very complex, because the 10-B is
far more than an improved tuning system; it is a completely new design con-
cept with many technical innovations
developed by Marantz engineers.
Q. Can you give us some examples?
Mr. Marantz: Yes. The RF section, for
example, contains a balanced-bridge di -
alltel
ffllitalk It 2Z
MARANTZ, INC., SUBSIDIARY OF
,
.
SUPERMPE c INC., SUN VALLEY, CALIF.
Circle 125 on Reader Service Card
AUDIO
45
DECEMBER, 1964
www.americanradiohistory.com
AmericanRadioHistory.Com
-I
INPUT
Vertical Tracking29, s°
DIFFERENTIATOR
CURVATURE
INDICATOR
DIAMETER
RI AA
EQUALIZER
-
INTEGRATOR
GROOVES
PER INCH
DISPLACEMENT
INDICATOR
Fig. 15. Schematic block diagram of the Recording Overload
Dynamic Styli Correlation
The master stereophonic dise record is
cut with a chisel stylus and the replica of
the master disc record is reproduced by a
ball -tipped stylus. Therefore, there is a
discrepancy23. 24.25.26.27 between the motion of the cutting stylus and reproducing stylus which becomes more pronounced at the shorter wavelengths. Figure 16 indicates that the introduction of
complementary distortion in the record 23
M.
J. Di Toro, "Distortion in the
Re-
production of Hill and Dale Recording,"
Journal S.M.P.T.E. Vol. 29, No. 5, p. 493,
1937.
24 J. A. Pierce and F. V. Hunt, "Distortion in Sound Reproduction from Phonograph Records," Journal S.M.P.T.E., Vol.
31, No. 2, p. 157, 1938.
25 W. D. Lewis and F. V. Hunt, "Theory
of Tracing Distortion in Sound Reproduction from Phonograph Records." Journal of
the Acoustical Society of America, Vol. 12,
No. 3, p. 348, 1941.
26 M. S. Corrington, "Tracing Distortion
in Phonograph Records," RCA Review, Vol.
10, No. 2, p. 241, 1949.
27 M. S. Corrington and T. Murakami,
"Tracing Distortion in Stereophonic Disk
Recording," RCA Review, Vol. 19, No. 1,
p. 216, 1958.
Indicator.
ing process will reduce tracing distortion
in the reproduction of the record. An
electronic system which provides this
type of distortion has been developed
and termed a Dynamic Styli Correlator.
Tracing distortion does not arise from
a simple nonlinear transfer characteristic
but rather is due more basically to a
phase modulation process. Accordingly,
the Dynamic Styli Correlator consists of
a delay line. The delay line in conjunction with the sampling gates provides the
proper electrical phase correction as a
function of frequency and amplitude so
that the electrical wave shape output of
the pickup in reproducing corresponds to
the electrical wave shape input to the
cutter in recording.
The Dynamic Styli Correlator reduces
the distortion by a very large order. The
reduction is 6 -to -1 at the inner grooves
of the record. A complete description and
the performance characteristics has been
A disparity between the effective vertical angle in the recorder cutting a modulated groove and the vertical tracking
angle of the pickup will introduce harmonic and intermodulation distortion in
the output from the pickup. A diagram
depicting the vertical tracking angle in
a magnetic pickup is shown in Fig. 17.
A diagram showing the geometrical tracking angle in a stereodise recorder is
CENTER OF
ROTATION
MOVING MAGNET
STYLUS ARM
+-DIRECTION
OF GROOVE
TRAVEL
17. Diagram showing the vertical
tracking angle in a moving magnet
pickup.
Fig.
DRIVING
FORCE
CENTER OF
ROTATION
i
documented.28
28 E. C. Fox and J. G. Woodward, "Tracing Distortion-Its Cause and Correction
in Stereodisk Recording Systems," Journal
of the Audio Engineering Society, Vol. 11,
DIRECTION OF GROOVE TRAVEL
No. 4, p. 294, 1963.
Fig. 18. Diagram showing the vertical tilt
angle in a stereophonic disc recorder.
A
A
NORMALIZED
DISTORTED
OUTPUT
ELECTRICAL INPUT
ELECTRICAL INPUT
y
STYLUS
STYLUS
AI -
DIRECTION OF
GROOVE TRAVEL
-GROOVE
MODULATION
X
GROOVE
GROOVE
Fig. 19. Distorted waveform of a sinu-
soidal vertical modulation played back
with a pickup having a vertical tracking
t'I/M/I9ìi,i/IIIA
angle Ø.
GROOVE CUT IN MASTER
GROOVE CUT IN MASTER
Fig. 16.
STYLUS
PATH
STYLUS
PATH
STYLUS
ting with predistortion.
PATH OF REPRODUCING STYLUS
PATH OF REPRODUCING STYLUS
D
STYLUS
(X) Cutting with no pre distortion; (Y) cut-
D
ELECTRICAL OUTPUT
ELECTRICAL OUTPUT
X
Y
shown in Fig. 18. A discrepancy between
the effective vertical angles of the cutter
and pickup will introduce nonlinear distortion as depicted in Fig. 19.
The effective vertical recorded angle of
the groove modulation may be considerably different from the design angle of
the recorder determined by the internal
29 J. G. Woodward and E. C. Fog, "A
Study of Tracking-Angle Errors in Stereodisk Recording," IEEE Transactions on
Audio, Vol. AU -11, No. 2, p. 56, 1963.
30 B. B. Bauer, "The Vertical Tracking
Angle Problem in Stereophonic Record Reproduction," IEEE Transactions on Audio,
Vol. AU -11, No. 2, p. 47, 1963.
(Continued on page 68)
AUDIO
46
www.americanradiohistory.com
AmericanRadioHistory.Com
DECEMBER, 1964
WHEN
KOSS
REK-O-KUT
PLEDGE
THEMSELVES
TO
QUALITY,
HERE'S WHAT THEY MEAN
When John C. Koss purchased control of Rek-O-Kut, he
discussed "quality" with Sid Simonson (Rek-O-Kut Manufacturing Vice -President) and Hal Dennis (Rek-O-Kut Sales Vice
President). "There's
a
reason why everyone thinks of
Rek-O-Kut as the very finest in single -play turntables. There's
a reason why every audio engineer in the business knows and
respects Rek-O-Kut equipment," said Koss.
"The reason," Simonson explained, "is that for over 25 years,
particular attention to purchase of parts and raw
materials. Then we tooled for absolute precision in machining
and assembly. If something wasn't perfect, we scrapped it!"
we paid
"Good," said Koss, "that's what do with our headphones
and that's what want continued with our turntables." And
that's what is now being done at the Milwaukee plant.
I
I
KOSS PRO -4 STEREOPHONES
$45.00
REK-O-KUT B -12H TURNTABLE
$165.00
Truly a professional instrument. Frequency response: 30Three speed. Noise level: -59 db below average recording
level. Wow and flutter: 0.085% RMS. Custom-built, heavy
20,000 cps. Impedance: 50 ohms to be used with 4, 8, or
16 ohm outputs. Fluid -filled ear cushions for positive seal
duty Hysteresis Synchronous motor for constant speed and
"hush" performance. On -off signal indicator.
and comfort over long listening periods. Highest quality drivers mounted in acoustically designed chambers provide unusually smooth frequency response. Equipped for boom mike
attachment.
Write for complete details and specifications on all Koss and Rek-O-Kut products.
KOSS
REK-O-KUT
2227 N. 31ST STREET
MILWAUKEE 8, WIS.
Circle 126 on Reader Service Card
AUDIO
47
DECEMBER, 1964
www.americanradiohistory.com
AmericanRadioHistory.Com
RECORD REVUE
Edward Tatnall Canby
Chopin Waltzes. Artur Rubinstein
RCA Victor LSC 2726 stereo
Old age is so rarely a time of supreme
fruition-except, it seems, among musiFor many long years, Artur
cians
!
Rubinstein was RCA's most brilliant
piano wheelhorse (and his concert
agent's, too), turning out millions of
minutes of steely, self-assured, powerhouse pianism. Frankly, I used to dislike
him rather vehemently.
No longer. Where once-if I can believe my memory-Rubinstein's Chopin
was the epitome of hard, brilliant whanging and banging, now in this new album
it is absolutely lovely. Self-assured of
course, and utterly confident no matter
what the technical difficulty. But musically effortless too, flowing like oil, sunny,
relaxed, alive, fluent. Never has this kind
of Chopin sounded to better effect.
For an artist like Rubinstein, it seems
to take the final coming -to -terms-with -life
of approaching old age to bring effort
and sincerity into focus with sheer technical know-how. In the last few years,
Rubinstein's recordings have shown such
a wise, human mellowness-minus bangs
and whangs-as only a man in his gifted
seventies could produce.
By golly, you can even use this one as
background music. Takes to it like a fish
in blue water and Chopin's dignity never
suffers. (Remember-his was the original
"salon music".) That's saying a lot, both
for Rubinstein and for RCA's mellow
piano recording.
Enough generalities
self.
!
and listen for your-
Go
Liszt: Piano Concerto No.
1
("Triangle").
Saint-Sains: Piano Concerto No. 2, Op.
22. Ruth Slenczyska; (a) Orch. of Vienna,
Melles; (b) Symphony of the Air, Swoboda.
Decca DL 710084 stereo
This lady with the consonentally Polish
name was a round, chunky little -girl prodigy
back before the War, right out of somewhere
in the good old U.S.A., if I remember rightly.
She retired into limbo, grew up and in due
time, not so far back, reappeared for a
grown-up try. She seems to have made it
OK. She's getting around now.
In these two show -piece war-horses she
shows herself oddly still a solid, chunky,
determined pianist, not much of a poetess in
the drawn-out lyric parts but a powerhouse
when the music at last turns rapid. The high
points in both of these concerti, decidedly,
are the scherzo -like movements, in the middle of the unbroken Liszt, the second movement of the Saint-Saëns, where she lets out
like a chubby race horse and flies over the keys
with terrific enthusiasm
I don't think much of either accompaniment. The anonymous Viennese orchestra
ought to know the Liszt better than it does;
the Symphony of the Air sounds as though
maybe it were almost -sight-reading the SaintSaëns. Both are OK, but on the routine side.
Ruth, with her 1920's boyish bob, carries the
music for them.
!
Albéniz:
XMAS-CELLANY
Beethoven: The Four Overtures to Fidelio.
Philharmonia Orch., Klemperer.
Angel 36209 stereo
Beethoven wrote only one opera-but managed to turn out four different overtures for
it, in a humped curve ; first an enormous
piece, ten times too big for any opera ; then
a concentration of that, shorter but even more
overpowering. Common sense, at last, led to a
mild third version, mostly but not all newit was never used. And finally, for an extensively recast revival years later, he composed the perfect overture, musically entirely
unrelated to the first three and, at last, on a
small enough scale to fit into its place at
the beginning of an evening's operatic fare.
Thanks to mixed-up publishing dates, these
are, in order, Leonore Overtures Nos. 2, 3
and 1, and the Fidelio Overture. (The opera's
name had shifted from Leonore to Fidelio.)
For many a year I've been hoping to find a
really first rate dramatic performance of all
of these in a single recording. Here it is.
Not many conductors are left who can
give the music the Germanic sweep and
clarity of Klemperer's performances. Almost
nobody (almost-to be safe) can reach the
intensity of these playings without hammering, thrashing, roughing-up the musical edges.
A maximum of power with a minimum of
harshness and sloppiness. An unerring sense
of style, precisely suited to Beethoven in
1965, combining modern terseness with a
classic take -your -time Romanticism
Suite Española; Pavaña-Capricho Cantos de España. Alicia de Lar rocha, piano.
Columbia MS 6603 stereo
This is an interesting import by Columbia,
recording by Hispavox in Spain itself. The
all -Albéniz program, played by a leading lady
pianist of that country, has an unusually authentic Spanish flavor, easily evident on the
hearing.
It's not always a total pleasure, I'd say.
This lady plays with immense fluency and
fine musicianship but her style (for our ears,
at least) is somewhat old fashioned and
tends to be a bit over -dramatic. A great deal
of fussy, if fluent rubato (slowings-down,
unevenness in tempo, for emotional effect).
Quite a drama of big-bang endings-one can
almost see the lady throwing her hands up
in the air in triumph at the end of each item
Very stagey, definitely. But what brothers a
casual listener most, I think, is a certain
blowing -up of music that is intrinsically not
too profound into something too big, too nationalistic for its own content.
The Suite Española, mostly lyric and fairly
quiet, gets nothing worse than a poetic, oldfashioned Romantic treatment. Pleasing, decidedly. But the other works, on the second
side, are of slightly sterner stuff and here
the lady plays almost furiously. Rather hard
on the stylus.
I wouldn't suggest this as a disc for tasteful background listening (which is where
most Albeniz finds itself these days) and
that, I think, is my best compliment to Alicia
de Larrocha. She is no mere parlor pianist.
!
O Great Mystery. Unaccompanied Choral
Music of the 16th and 17th Centuries.
The Canby Singers, Edward Tatnall
Canby.
Nonesuch H-71026 stereo
As my alter ego the record reviewer I give
brief mention to this item which, in my capacities as conductor, recording director and
tape editor took me a total of four years' on and -off work and most of last summer to complete. Very good for a reviewer's too -callous
soul, to see how hard it is to make records.
The music is all unaccompanied, featuring
on Side 1 three settings of the Christmas text
Magnum Mysterium (O great mystery, that
the animals should see the birth of Christ.
.
.
.) by Victoria, Morales and Byrd, plus
works by Lassus and another Spaniard, Guerrero. Side 2 has a variety of music, more contrasted, including a couple of slightly zany
love songs-Waelrant, Schütz, Handl, Melchior
Franck, Schein and Monteverdi are the composers.
What I like about the music is the perfect
tuning and clarity of the harmonies, the lack
of vibrato in the voices (I picked 'em that
way) and the consequently pleasurable ease
in the listening, abetted by the fine acoustics
of the chapel of the General Seminary in New
York. As the ads say, you'll enjoy. . . . etc
etc.
O
Maurindo Almeida-Guitar Music from
the Romantic Era.
Capitol Duophonic DP 8601
The "Duophonic" series is made from mono
originals treated for synthetic two -channel
recording for playing on stereo machines.
(See "Audio, E.T.C.," October 1964.) The
solo guitar definitely benefits, on my equipment at least, from the more immediate sense
of space and presence added here by the
synthetic "stereo." For a solo instrument-a
"point-source"-this enhancement might logically seem unnecessary. But it does help, not
in spreading the instrument out but in setting
it acoustically within a more immediately
sensed space.
My only technical objection here applies
both to mono and "stereo" versions; the original recording seems to have an unconscionable
amount of bass for a mere guitar and (perhaps as a consequence) a rather dull sounding
treble. Could be miking, or even the frequency
response of the original recording equipment ; it also might be no more than faulty
equalization, trusting to formula rather
than the evidence of the ear. Who knows?
Nice playing of a batch of classical transcriptions of Romantic-perod tid-bits by
Beethoven, Schumann, Chopin, Masseet,
Grieg, Debussy, and one Mozart theme put
to guitar variations by the ever-present Fernando Sor.
Piano "Pops" Promenade. Leonid Hambro, Jascha Zayde, duo -pianists.
Command CC 11023 SD stereo
Amazing how musical talent and energy,
these days, can erupt in unlikely ways such
as this, a battery of two -piano "arrangements" that come close to being re -compositions for two pianos. One, indeed, is just that,
a set of Variations on a brace of earlier
(Continued on page 61)
AUDIO
48
www.americanradiohistory.com
AmericanRadioHistory.Com
DECEMBER, 1964
JBL PRESENTS THE
SOLID STATE STEREO
GRAPHIC CONTROLLER
nT3AA3=
®®
I
I
a:
A TOUR DE FORCE OF CREATIVE ENGINEERING
Straightline controls. Pushbutton selectors. Inputs in front as well as
back. Take a look and wonder...Isn't this the way it should have been
done in the first place? The JBL design staff started fresh. Clean slate.
No restrictions, prejudices or preconceptions. With cold objectivity
they regarded the functions of a preamplifier/control center, re-evaluated its relationship to a human operator, weighed every conceivable
feature. Straightline controls give immediate visual indication of setting. Even from a distance. Direction of movement seems intuitive.
Up to increase, down to attenuate. Slide to one side or the other to
balance channels. Pushbutton selectors permit instant comparison,
switching from one source (top bank) or mode (lower bank) to another
without passing through intermediate positions. Pushed button lights
up. Controls are sa arranged that those most frequently used are most
accessible. Human engineering. Front -panel inputs permit sampling
and comparing components, connection of portable units without disrupting permanent rear-chassis connections. Front jacks are behind a
flip -down door which also conceals occasionally used facilities such
as a headphone jack, fuse, filters, system gain, level and balancing
controls. The Graphic Controller includes a 1,000 cycle test tone generator to be used for speaker balancing, placement and orientation. An
Aural Null Stereo Balancer accessory provides a very precise means
for balancing speakers, and also the two signals from your stereo
pickup. Performance-wise-in terms of response, distortion, hum-the
JBL solid state Graphic Controller is the finest instrument of its kind
you can buy. As has been said of other JBL products, "It's the result
of doing everything right." In fact the Graphic Controller is so right
in every respect, so well built, so well engineered that yours might
very well become a family heirloom. There's much more to be said
about the SG520. You'll find a complete description in Bulletin SL801-2.
Write for your free copy and the name of the Authorized JBL Audio
Specialist in your community.
The Graphic Controller is designed, engineered and manufactured by:
JAMES B. LANSING SOUND, INC., LOS ANGELES 39, CALIFORNIA
Circle 127 on Reader Service Card
AUDIO
49
DECEMBER, 1964
www.americanradiohistory.com
AmericanRadioHistory.Com
EQ W PM E N?
®e®
.O
FM
O O
o
PROfI
BOGEN SOLID-STATE
FM -STEREO RECEIVER,
MODEL RT -6000
kind have been available for several
years now and so have the devices.
The name Bogen has graced many
fine high fidelity instruments over the
years, extending back to the origins of
high fidelity. Throughout this period
they have been known as a maker of
well-designed and well -engineered products. When Bogen literature specified
performance characteristics, you could
be sure that the product you bought
would perform that well, if not better.
The RT -6000 is no exception; it performs exceedingly well, as claimed.
The RT -6000 is an FM -stereo tuner a
stereo control center, and a 50 -watt rms
stereo amplifier, all on one 16" x 14"
chassis which is 51/2' high.
We should restate that slightly : The
RT -6000 is a completely solid-state FM stereo tuner, control center,
.
Only a few months ago there was nary
a completely solid-state receiver to be
found. Without going into a lengthy
discussion of the subject we must point
out that it is much more difficult to make
The RT -6000 incorporates inputs and
controls for accepting signals from a
stereo tape head, a stereo magnetic cartridge, and a stereo high-level source, in
addition to the built-in tuner. Outputs
are provided for stereo recording and
monitoring the recording. A headphone
jack is provided on the front panel and
slide switches are provided to select
speaker or phone output as well as the
monitor mode.
In addition to the usual tuning, volume
balance, bass, and treble controls slide
switches are provided for a.f.e. defeat,
loudness defeat, stereo or mono mode
selector, and stereo reverse. The source
selector also permits selection of FM
Mono or FM Auto.
In the FM Auto position of the selector, the set is automatically switched between the mono and stereo modes of FM
reception depending on the availability
of an FM -stereo source. Switching is
completely silent and undetectable audibly.
A meter is provided to indicate FM
signal strength.
Before leaving the front panel, it
should be noted that the styling is quite
handsome. The entire front panel is
brushed gold and the knobs are also gold colored. Its a pity the slide switches
aren't gold too, instead of the usual dark
brown.
The slide -rule tuning dial is of the new
..
a completely solid-state tuner perform
at compenent high fidelity standards
than a tube unit. The Bogen RT -6000
is evidence that the problem can be
solved.
Also, at the amplifier end of the instrument, the RT -6000 demonstrates a
refinement of performance as compared
to previous solid-state amplifiers with a
similar output configuration. This we
would expect. After all circuits of this
"expanded" persuasion, measuring almost 7-in. in length. In addition, a logging scale is provided just below the
megacycle scale. Very convenient for explaining the location of stations to the
non -technical user. Certainly 4 is easier
to use than 96.3 mc.
Control Center
Fig.
1.
Bogen
RT -
6000 solid-state
FM -Stereo
er.
Receiv-
Circuit
Viewing this solid-state FM circuit
and comparing it with tube FM circuits,
one is struck by the basic similarity. Except for some circuit constants related
to tubes or transistors as devices, one
could superimpose tubes in place of
transistors throughout. If one takes off
the bottom plate and examines the underchassis, it is very difficult to tell
whether there are tubes or transistors on
the top side except for the absence of
tube sockets. The same rats nest of pointto-point wiring exists as has existed for
many years.
Thus we note a common base
(grounded grid in tubes) r.f. stage,
straightforward mixer and oscillator
Following are four i.f. stages with a tap
at the last stage to drive the meter circuit. A.f.c. voltage is taken from the
output of the ratio detector.
The multiplex circuit is also straightforward and reflects the latest thinking.
A circuit is included which decides when
there is sufficient 19 kc pilot signal present to indicate a stereo program (some
19 kc is almost always present as harmonics of the audio signal or from other
sources, but much lower in level than the
pilot signal). If there is not enough pilot
signal, the circuit "switches" the output
to mono. The switching is electronic,
which accounts for its speed and quietness.
Amplifier Circuit
The amplifier circuit is also quite
usual, employing feedback networks to
achieve tape and phono equalization as
well as bass and treble compensation.
The phono input is loaded with 47k
which is quite usual. The aux input is
divided down to make it less sensitive
rather than have it enter the circuit
past the preamplifier stages. Thus if a
sensitive uncompensated input is required, a microphone input for example,
all one need do is remove some resistors.
The first two preamplifier stages are
a 2N2613 and a 2N591 in that order. An
output is then taken for the tape output
which has another stage of amplification,
a 2N408. The ganged volume control (all
basic controls such as volume, bass, and
treble are ganged) and the loudness
compensation circuit precede the next
amplifier stage, a 2N408. The following
tone driver stage is also a 2N408.
The power amplifier section follows,
with the signal going through a 2N2614
AUDIO
50
www.americanradiohistory.com
AmericanRadioHistory.Com
DECEMBER, 1964
and a 2N408 to reach the driver transistor, a 2N2148. This is a rather husky
driver section and is undoubtedly an
important reason for the good performance of this circuit. The driver transistor
feeds a transformer which acts as a
driver to the push-pull output stage.
consisting of a pair of 2N2147 transistors. A positive and negative supply of
22 volts is provided the output stage by
a bridge rectifier in the power supply.
Both supplies are fused as are the
speaker output leads. There is no coupling capacitor to the speakers, thus eliminating a possible trouble spot.
The power supply for the remainder
of the circuit is provided by a rectifier
consisting of two diodes and then
through a 40050 transistor in emitter follower configuration which supplies -38
volts, and then through two 2N408 transistors, also emitter followers, which supply -25 volts.
The amplifier circuit is designed to
provide optimum power at 4 ohms, as we
will note in the performance characteristics.
Performance
Starting with the tuner section we
found sensitivity to be 2.7 µv (IHF),
crossmodulation index 65 db, selectivity
(alternate channel) 37 db, capture ratio
4 db, AM rejection 55 db, and excellent
pulse noise rejection. The RT -6000
pulled in 34 stations loud and clear on
our standard antenna.
The amplifier section exhibited a very
smooth response, being only 2 db down
at 15 cps, rising to 0 -db at 1000 cps and
continuing smoothly to a level of 1 db
at 10,000 cps, returning gradually to the
the 0 level at 20,000 cps, and then going
down 1 db at 50,000 cps. This response
was obtained at 20 watts rms at an impedance of 5 ohms. Power output at 5
ohms was 24 watts rms at a distortion of
0.7 per cent. At 8 ohms the output was
less by about 20 per cent. Power bandwidth was 20 to 20,000 cps. IM distortion was just under 1 per cent with a 60
and 7000 cps signal mixed 4 -to-1 at an
equivalent output of 20 watts.
Altogether, the Bogen RT -6000 is a
fine performer at a surprisingly low
price. As far as we know its the first
solid-state component-quality receiver at
Circle 211
less than $400.
ACOUSTIC RESEARCH
SPEAKER SYSTEM
AR -4
Acoustic Research has been the leader
in the fight for acceptance of compact
speaker systems on their own merits
without regard to price. While there are
still holdouts, most responsible music listeners acknowledge the AR -3, Acoustic
Research's senior system, as a major contribution to the art of reproduction.
Certainly, at least, the 14 x 25 x 113/s -in.,
$225, AR-3 is established as a well
AUDIO
As with the senior AR systems, this
one sounds better the louder you play it.
And, it will not break up under any
signal likely to be presented to it under
home conditions.
The AR -4 was frequency swept in an
effort to correlate what was heard against
an established standard. Subjective
evaluation of the sweep showed that the
AR -4 dropped off sharply below 50 cps.
If lower frequencies were forced into
Fig. 2. AR -4 Speaker System.
the speaker, there was slight doubling,
known speaker of (incidentally) modest but for all practical listening purposes
dimensions.
there was no response below 50 cps.
Now comes the AR -4, their latest en- Above that frequency, however, response
try. This system is 19 x 10 x 9 -in. and was smooth, without obvious peaks or
costs a mere $57 in oiled walnut and valleys, to well above audibility. Our
And, as in- system was adjusted, via the rear tweeter
$51 in unfinished pine.
credible as it may seem, these two sys- control, to suit our preferences. At this
tems are sonically related.
setting we found that highs were all
The AR -4 is a two-way system em- there, but that there was a slight rise
ploying an 8 -in. woofer with what is in response from 2000-6000 cps. This,
commonly called acoustic suspension. and not any actual rolloff, we suspect,
This is crossed over to a 3.5 -in. wide - was responsible for the musical effect of
dispersion tweeter. This tweeter is con- slightly diminished high -end response.
trolled by a rear panel pot that permits On an over-all basis, we judged this
tailoring of the system to room acous- speaker to have an outstanding fretics. Efficiency of the system is mod- quency response and sweep characteriserately low. AR recommends, and we tic. And without regard to its price
would agree with them, that a minimum level.
In conclusion, then, the AR -4 is not
of 15 watts rms should be used to drive
the speaker. Connection is made to the 8 - one of the great speakers. But we doubt
ohm tap of an amplifier.
that this is what was intended by Acoustic Research, if, in fact, a great speaker
How it Sounds
can be made for so low a price. But
For any speaker system in this price the AR -4 is a speaker designed for a
class it would be an easy task to essay budget that, at the same time, wants unwhat is wrong with it, from an absolute usually high musical quality. The AR-4
sound point of view. The AR -4 is no can be listened to for hours on end,
exception in this respect. Yet, it might without fatigue.
Circle 212
also be said that it would be a most
difficult task to find anything right with
so low-priced a product. This is not the
case here. Let it be stated immediately WEATHERS "TOWNSEND"
that the AR -4 is a most listenable speaker STEREO TURNTABLE
musically.
To this new single -speed turntable one
Subjective listening tests reveal that
it simply does not have deep bass. And could readily apply the old expression
for it
there seems to be a rounding off of the "Handsome is as handsome does,"
appearin
attractive
most
extreme high end as well. But these is certainly
effects are not obvious as those two sen- ance and its performance should enhance
tences would lead you to believe. The many a stereo system. With its over-all
musical balance of top end to bass is height of just a bit over five inches and
141/4 inches,
so well controlled that there is the base dimensions of 17% by
capable of
yet
compact,
all
of
first
is
exists.
it
actually
than
bass
effect of deeper
its satin With
The top end too, is similarly affected. high -quality performance.
base,
walnut
chassis,
aluminum
you
finished
the
way
exactly
sounds
The AR -4
would expect a scaled down AR -3 to and walnut arm with aluminum fittings,
sound. The family resemblance is un- it is modern and functional in appearmistakable. The over-all sound is sub- ance.
The concept of a constant -speed syndued and a bit pinched, yet not in any
way difficult to listen to. There is no chronous motor of small dimensions drivraggedness or roughness in the AR -4. ing directly a light -weight platter has
Male voices lacked fullest roundness and been delineated before in these pages,
the female voice was dulled when the and is accepted as valid. In the "TownAR -4 was compared with several sys- send" a 12 -pole synchronous motor of
tems costing four to five times its ask- clock proportions is fitted with a 11/16"
dia. rubber drive puck on its shaft which
ing price.
when
transmits its motion directly to the inner
suffered
also
Transient response
compared, but only slightly. Yet it is rim of the aluminum turntable and the
amazing how well this speaker did hold spindle rides in a Delain bearing. The
(Continued on page 62)
up against the high-priced stuff.
51
DECEMBER, 1964
www.americanradiohistory.com
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NEW
Oscilloscope Kit. Eico's new 3 -in. a.c.d.c. scope kit features distortionless vertical and horizontal trace expansion to several times screen diameter and drift -free
positioning allows examination of waveforms with as much detail as with 5"
scopes. Vertical response is flat + 1 - 3db
from d.c. to 4.5 mc. Sensitivity is 18 mv
per centimeter rms and 50 mv/c peak-to peak. Input impedance is one megohm
shunted by 35 pf. Horizontal response is
+ 1, - 3 db 1 cps to 500 kc with a sensitivity of 0.7 volts per centimeter rms.
Input impedance is 4 megohms shunted
by 40 pf. Intensity modulation input sensitivity is 3 volts rms for blanking and
input impedance is 2.2 megohms. A 10
PRODUCTS
for $9.50 and a hand -rubbed walnut case
for $29.50.
Circle 201
Periodic Principle PM Antennas. Based
on a principle of antenna design already
successfully used in a line of TV antennas,
Jerrold Electronics has announced three
new antennas specifically cut for the full
FM band. Known as FM Paralogs, these
are highly directional arrays. A high degree of rejection of unwanted signals is
claimed for this line. As a result, a significant reduction of the problems of
multipath FM -stereo interference will be
realized. Mechanically, these antennas feature Cycolac insulating mounts. This is a
very tough plastic also used for golf club
heads. A wedge -snap lock provides permanent joint connections which tighten
with wind vibration. Made by Jerrold's
TACO subsidiary, they are priced from
$29.95 to $59.95.
truded aluminum plate. A full-size and
full color instruction manual, with matching Parts -Charts make for fool-proof kit
assembly. All mechanical parts, terminal
boards, tube sockets and the like have
been pre -riveted at the factory. All wires
are pre-cut to length and pre -stripped.
Important specifications include an output power rating of 40 watts per channel
(IHF), and a power bandwidth of 20-20,000
cps ± 1 db. Frequency response is also
stated as ± 1db from 20-20,000 cps with
harmonic distortion of 0.8%.
Circle 204
All Transistor 100 -watt Amplifier. Rauland -Borg Corporation has made available
the Model TA100 all -transistorized 100 watt amplifier designed for continuous duty service in commercial and industrial
application. Companion Model TA50, a 50 watt solid-state amplifier, is also available.
The Model TA100 features: 100 -watts rms
Circle 202
Pushbutton Stereo Recorder. Recently
announced by Lafayette Radio is a new
four-track stereo recorder, the model RK-
Selling for $179.95, the recorder plays
and records four -track stereo and monophonic tapes at both 7.5 and 3.75 ips. Two
level meters, a digital tape counter, and a
pause control are incorporated for maximum recording convenience. Frequency
response at the faster speed is 40-18,000
cps. At the slow speed top -end response
is reduced to 12,000 cps with no change in
bass response. Built-in amplifiers give an
675.
volt peak -to -peak sawtooth, with an output impedance of 300 ohms is available
from 10 to 100 kc. The cathode ray accelerating potential is 1500 volts. The same
gun as in a 5 -in. tube is used which results
in greater sharpness and brightness. Extremely fast retrace permits viewing a
complete single cycle at the highest sweep
frequencies. Also provided is a 200 mv
peak -to -peak calibrating voltage zener
regulated to ± 5%. Weight is 15 lbs. It is
8% -in. high, 5% -in. wide, and 12% -in. deep.
The Eico 435 oscilloscope is priced at $99.95
in kit form and $149.95 factory wired.
Circle 200
(200 -watts peak) output; thermostatically
controlled protective relay; back-up fast acting overload protective relay; instant
operation-no warm-up required; low
power consumption; approximately 75 per
cent less heat dissipation than in tube
amplifiers; frequency response, plus or
minus 1% db, 50-15,000 cps; distortion less
than 5 per cent at rated output (less than
3 per cent at 80 watts); noise level, 80 db
below rated output.
Circle 205
Improved Stereo Receiver. Sherwood's
new S-7700III 80 watt music power FM
stereo tuner -amplifier is the first such
product to incorporate circuits and builtin test points for connection of an oscilloscope for direct visual display of incoming
signal characteristics. A high fidelity installer can thus identify the presence, degree and direction of multipath interfereo ,. .A
with this information, he can
1
..
as1:M=INI
_.
..
,
-
ar
.... a .....
--m
orient the antenna and tak, Ila r necessary steps to eliminate this serious stereo
reception problem. This all-inclusive component provides AM, FM and FM multiplex
broadcast reception, as well as inputs for
record players and tape decks. Two 40 -watt
music -power channels are provided with
outputs for 4-, 8-, and 16 -ohm speakers.
A separate powered center channel speaker
output is also provided. The front panel
contains a low -impedance earphone jack.
Important specifications include: 36 watts
per channel rms output; IM distortion is
claimed at a maximum of 1.5 percent; at
full rated power output response is 20 to
20,000 cps ± 0.5 db. Dimensions of the
component measure 16% x 4 x 14 -in. D.
Cost is $374.50. Also available as optional
accessories are a leatherette -on -metal case
..
...
....
audio output of 3 watts per channel. Stereo
separation of 45 db is claimed at the amplifier output. This is maintained by builtin speaker flaps that disperse the sound
from the two 6 x 4 -in, speakers on either
side of the recorder. Wow and flutter is
stated as 0.2% at 7.5 ips and 0.25% at 3.75
ips. The RK -675 comes complete with two
dynamic microphones, cables and take-up
reel, all contained within a simulated
leather case measuring 161,E W x 7 H x 12%
D.
Circle 203
Amplifier Kit. H. H. Scott has just announced the LK-72B 80 -watt stereo amplifier kit. This is an integrated kit with
facilities for phono and tape decks, separate channel tone controls, a derived center channel speaker output and Scott's
subsonic filter circuit to prevent waste
of useful power. In keeping with the latest
styling from this company, the front escutcheon has been redesigned as an ex-
52
New Medallion Speaker System. In a
move to supply a speaker system with the
sound of its Medallion and with its
changeable grilles, University recently introduced the Medallion Monitor. The
Monitor is a fixed grille bookshelf version
of the Medallion XII with improved versions of the three speakers presently being used. It consists of a 12 in. woofer, an
8 in. mid -range and the Sphericon Super
Tweeter. Response of the unit is claimed
to be virtually undistorted from 20 to
40,000 cps. Finished in oiled walnut, the
Medallion Monitor is priced at $129.00 net.
LTV University.
Circle 208
AUDIO
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AmericanRadioHistory.Com
DECEMBER, 1964
'UNEXCELLED
by any other Tuner!"
Audio, February,1964
,..
mom
...
era 411840
McIntosh
Mill STEREOPWONIC
F
M
INNER
need we say more?
-11113e-
$30 down and only
$10 a month
from most dealers!
McINTOSH LABORATORY INC.
6 Chambers St., Binghamton, N. Y.
Send for FREE INFORMATION
MR 67
6 Chambers St.
Binghamton, N.Y.
Please send me MR 67 information
NAME
STREET
CITY
Circle 128 on Reader Service Card
AUDIO
DECEMBER, 1964
www.americanradiohistory.com
AmericanRadioHistory.Com
STATE
53
New Trusonic Speaker. Trusonic has introduced "Lyra" as the first of its new line
of packaged speakers. The new unit measures 14" x 16" x 4". This size was planned
to make Lyra fit into any space demanding
a compact speaker. Within each cabinet
are two miniature speakers. Each speaker,
"The greatest contribution
we've made
towards upgrading WKFM"
FRANK KOVAS, PRESIDENT
WKFM, CHICAGO
a new type named the CR-50, will handle
over 25 watts of power with smooth sound
from 25 to 20,000 cps. The cabinet is made
of select walnut. A black hairline is set
into the sides to enhance the Italian finish.
Also featured is Trusonic's lifetime warranty.
Circle 207
Scott Speaker System. H. H. Scott has
announced the introduction of its S-5
speaker system. The S-5 was especially
designed for use in the Belgian Village at
the New York World's Fair, and is a twoway loudspeaker system employing a specially -designed low -resonance woofer and
s
TU D
I
STEREO
TRANSCRIPTION
PREAMPLIFIER
CJ
Certified quality because every characteristic on every unit is checked to make
sure it passes specifications. That's why
Mr. Kovas says "It is unfortunate that we
(WKFM) wasted so much time in experimenting with hi fi type stereo preamps
which looked good on specifications ...
I'll have to admit that nothing equals the performance of the Shure SE -1 for stereo
multiplexing."
What are the certified specifications? The SE-1 has plenty of gain to feed a 600 ohm
line at +4 or +8 dbm from a magnetic stereo phono cartridge and still provide for
peak power. (1.2 my input gives at least +4 dbm output.) Balance is provided with
separate gain controls for each channel. True RIAA equalization with ± 1 db 30 to
15,000 c.p.s. of RIAA curve. Optional flat position for measurement and calibration
in the studio. Separate high and low response trimmers for each channel with NO
interaction between channels, or between high and low end. Hum and noise level
at least 64 db below output level. Channel separation better than 37 db between
50 and 10,000 c.p.s. Distortion is under 1% at +15 dbm 150 or 600 ohms output
impedance. Compact size (7" x 3%" x 11" deep)
Convenient slip -in mounting
for easy installation. Separate power supply reduces panel space requirements.
Priced at only $295 net. Write for technical data sheet: Professional Products
Group, Shure Brothers, Inc., 222 Hartrey Avenue, Evanston, Illinois.
-11
...
CIRCLE 158
54
a high -frequency tweeter. Specifications:
8 -ohm impedance: frequency response _+5
db from 60 to 15,000 cps. Dimensions: 10" x
16" x 6%". Weight: 12 lbs. Price: less than
$60.
Circle 208
NEW LITERATURE
Magnetic Tapes Bulletin. Electromagnetic and physical properties of magnetic
tapes are described in a new six -page brochure now available from Reeves Sound craft. The color catalog provides both
properties and complete specifications for
Reeves Mylar and cellulose acetate base
tapes for sound recording. The bulletin is
listed as RS -64-18.
Circle 209
Sonotone Product Catalog. Sonotone's
Electronic Applications Division is distributing its new audio product catalog,
covering the firm's OEM, distributor and
consumer products in the hi-fi and electronic field. The 16 -page catalog illustrates, in detail, Sonotone's complete line
of ceramic and crystal cartridges, replacement needles, tonearms, ceramic microphones (including low -impedance types)
and learning lab headset/microphone units.
It also shows the Sonotone speakers and
new speaker enclosure systems as well as
the company's rechargeable flashlight battery cartridges
Circle 210
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
DECEMBER, 1964
New, revolutionary way to
choose a speaker system:
listen
UNIVERSITY
COMPANION II
Ultra -Linear
10" woofer,
3" mid -range,
31/2" tweeter.
24x131/2x111/2"
D. $79.50
UNIVERSITY SENIOR II
Ultra -Linear 12" woofer, 31/2" mid -range, Sphericon
Super -Tweeter; 25x155/8x121/8" D. $99.50
UNIVERSITY MINI -FLEX
61/2" woofer, 3" mid -range
31/2" tweeter. 15x9%6
x5%6" D.
UNIVERSITY COMPANIONETTE
Ultra -Linear 8" woofer,
3" mid -range, 31/2" tweeter.
213/4x111/2x85/8" D. $69.95
$69.95
...and listen and listen.
New? Revolutionary? Yes-when you consider how many people buy speakers
based on the recommendation of others. Sound involves subjective criteria. The sound that pleases a friend,
hear and compare
(a hi-fi editor or salesman, for that matter) will not necessarily please you. Therefore
many systems. For the largest selection, start with University. Choose the superb University model that best
meets your requirements, then compare it to all other brands of its type. For example-if it's a full-size bookshelf you want, ask your dealer to demonstrate the Senior II vs. the AR, KLH, and other bookshelf systems of
similar size. You'll hear the d fference. Especially in the mid -range. Especially in the Senior's complete
absence of restraint, that tell -tale drawback of so many other bookshelf systems. Unlike other systems, the
sound of the Senior, the Companion, or of every University system, large or small-is free and open. The
bass is cleanly defined; the mid -range punches through for greater presence; the highs literally have wings.
and listen. University sounds better. Free 1964 Guide
Want proof? (Of course you do) Visit your dealer
to Component Stereo! Write: Dept. R-12.
...
...
LTV
UNIVERSITY
A DIVISION OF LING-T£MCO-VOUGHT. INC.
9500 West Reno, Oklahoma City, Oklahoma
Circle 115 on Reader Service Card
AUDIO
55
DECEMBER, 1964
www.americanradiohistory.com
AmericanRadioHistory.Com
COMMERCIAL SOUND
(from page 42)
enough"
much !"
ground,
or
Moo
The system should have just
one straightforward ground connection, from input to output,
and with no extra connections
bypassing the "official" one. If
there is a break in the intended
connection, or one piece of
equipment fails to get its ground
at all, or even if the official
do you have a monkey wrench
in your automatic turntable?
Any spindle that permits the stacking of records on a
turntable throws a monkey wrench into the entire system.
-
The stacking of records varies the stylus angle increases
the load on the motor-creates flutter and wow-wears
records-diminishes your listening pleasure. IS IT WORTH
ALL THAT JUST TO CHANGE RECORDS?
-
Recognized as the finest performing transcription turntable, the Thorens TD -124 features 4 speeds,
built-in illuminated strobe, flawless sound. Unmatched
for mono or stereo reproduction.
Net $125
TD-121
If you demand top quality yet need only a
single speed, see the Thorens TD -121. Converts to any
standard speed you select. Flawless performance, as in
all Thorens equipment.
Net $85
TD -124
TD -135
-
Here is a precision 4 -speed transcription turntable with an integrated Thorens tone arm (BTD-12S), for
those who prefer a complete, compact unit. Exceeds NAB
standards for rumble, wow and flutter. Features 12 -inch
non-magnetic table, variable speed control, precision mounting. Tone arm has amazingly low tracking error, and is
designed for lowest possible inertia and friction. No other
integrated unit approaches the professional standards and
economy of the
ID-135.
Net $99.75
-
If you want highest performance plus convenience, see the amazing Thorens TD -224. There is no
other instrument like it in the world. Combines the playback quality of a transcription turntable with the convenience of an automatic record changer. There is never a
record stack on the turntable, yet records change automatically. Overcomes all problems of "automatics.' TD -224
incorporates the BTD-12S professional tone arm, plus a
built-in record cleaner, illuminated strobe, variable speed
control. A superb instrument with features never before
combined in a single instrument.
Net $250
TD-224
ground takes an unduly lengthy
route (longer than the signal
path, for example) this can
cause hum. Check your ground
connection with a continuity
tester. You'll find a break or
omission that way.
Then if there is already a
complete ground connection and
another is inadvertently connected (or even deliberately,
with the idea of providing
"good measure") you may even
get worse hum than that due to
a partially missing ground. This
you can check by breaking the
intended ground path and using
the continuity tester to see
whether it really does break, or
whether there 's another connection you don't know about, or
forgot about.
Suppose, for example, your
system includes tape recording
facilities. For complete grounding according to rule, when recording the tape recorder's
ground should be picked up at
its input, from the ground point
on the system feeding it (the
tape output on the amplifier) ;
on the other hand, when the tape
OTHER
INPUTS
PREAMPLIFIER
w
LPOWER AMPS
THOIZENS
A
RECORD
/CONNECTION
sound R 'creation * Product
PLAYBACK
CONNECTION
TAPE RECORDER
If your dealer can not qualify for a Thorens Franchise-go to another one!
I
ELPA MARKETING INDUSTRIES, INC., Dept. A-12, New Hyde Park, New York.
* sound 1z]creation
-
A Mark al Elpa Marketing Industries, Inc.
In Canada:
Trl-Tel Associates, Ltd., Wlllowdale, Ont
CIRCLE 129
Fig. 9-7. Connection of recorder to system discussed with reference to double grounding hum problem.
AUDIO
56
www.americanradiohistory.com
AmericanRadioHistory.Com
DECEMBER, 1964
is being used on playback, the
ground should come from the
tape recorder's output to the
amplifier input to which it connects. Switching is usually incorporated to separate these
functions, so that both connections can be made permanently,
as far as the relevant connectors
are concerned. Unless the
switching breaks the ground, as
well as the signal circuits, there
may be hum because of the
ground loop so created.
If it is not practical to have
the switching break ground connections, you will have to find a
way of connecting so there is
only one ground connection.
Usually the safest thing is to
break the ground connection associated with the transfer that
AUDIO
occurs at the higher level, and
let the lower level ground carry
for both. The high-level ground
tie operating with the low-level
transfer is more likely to cause
hum than vice versa. (Fig. 9-7).
So, if the output from the tape
recorder is at lower level on
playback than the signal fed to
it on record, use the playback
ground connection and break the
record connection. On the other
hand, if the input to the recorder
for record is at lower level than
its playback output, use the record mode ground, and break the
playback connection. Where the
difference in level is not great,
or both are equal, you may find
that you have to either change
connections every time, or devise switching that does.
Getting
only half
the sound?
Hear it all with the new
.1A4
r.
ETC
(from page 12)
You see, in earlier years we have had
formist myself in this audio world of
ours and I treasure almost any old in- a number of neutralist, gray -flannel
dividuality that manages to survive in speakers around-for a long time, in fact
-but the average ear couldn't really tell
our dun -colored time.
The individualist speakers have a dis- them apart from the others. With so few
tinguished tradition behind them. Many of them, relatively, their particular color
an old line's reputation has been built didn't seem special one way or another;
You get all the fidelity your records can deliver
upon the maker's very special sound, and they were simply one more type of sound, - the full, rich sparkle of stereo sound - when
But
that was you install the revolutionary new elliptical stylus
for many long years people have liked among many to be heard.
these specialties. (Just as they once liked before the Sound -Alike Club, my private by Ortofon. It has no equal anywhere.
This new elliptical stylus, called a "major breakthe Chevy radiator pattern, or the Ford, club, came into existence.
Now, you see, the big change is upon through" by one leading authority, obsoletes all
or the Packard or Auburn, so clearly
previous cartridge ratings. It eliminates or sharply
different and characteristic from each us. That's what I heard at the autumn reduces the compromises and distortion factors
created by conventional spherical styli. It also remanufacturer.) People have bought thou- hi fi show. Everywhere, in room after duces
record wear, minimizes surface noise and
sands of dollars' worth of speakery for room, more of those gray-flannel sound - faithfully follows the configuration of the record
moved
Until
as
I
about
alike
speakers.
groove. The result is a brilliance of performance
their home componentry (and its clasbefore expected from recorded music. Once
sical musicry), all on the basis of these I became attuned to this new sound, so never
you hear it, you will never be satisfied with anyand
neutral,
so
uninteresting
unobtrufamiliar and well -established styles of
thing less.
speaker sound. That was, and is, their sive, I clean forgot all about it through The Ortofon Elliptical Stylus is priced at $75.00
sheer repetition and my interest shifted net. If you mow own an Ortofon Stereo Cartridge,
privilege.
the many other fascinating aspects of you can trade up to the new Elliptical Stylus for
It is also the manufacturer's privilege to
$25.00. Ask your dealer for a demonstration.
the hi fi scene. (Same with other people. only
Hear the difference. Get the full sound your rec.
to eater to these solidly differing tastes,
Couldn't keep their minds on these color- ords were meant to deliver. You will find the exto build and to plug his own type of
perience richly rewarding.
less speakers.)
speaker sound and continue to sell it to
That is-until I entered a room where Model SPE/GT-Pre-mounted for Ortofon tone arms
every willing customer who finds it imone or two of the non -conformist speak- Model SPE/T-Unmounted for universal use
pressive, as plenty still do. That's the
ers were still going full blast, with their DON'T COMPROMISE! If your dealer doesn't
way the system has worked, and still special sound-and what a shock It hit qualify for an Ortofon Franchise, go to a dealer
does.
whose standard of quality includes Ortofon prodyou in the face, after the gray flannel
It still does, but alas, individuality is effect, and it hit you unpleasantly. Some- ucts. You'll appreciate the difference.
Ortofon RMG 212 arm
weakening, I'm afraid. The new factor times, looking at the distinguished names,
most
$55. net
on the scene today, the audible scene, is I was incredulous; I could scarcely bethoroughly professional
the gray flannel suit in speaker guise. lieve my tired ears. That's what happens
the
on
arm
12" stereo
market. Ortofon arme
And it is spreading fast. The end result after too much continuous exposure to
cover the price range
is going to be inevitable.
gray flannel sound. Color-any colorfrom $20 to $60 net.
The more of these conformist, sound - sounds awful.
ELPA
Don't think the public isn't going Write for free catalog
alike, speakers there are, the more will
experience.
through
this
very
same
It
the neutral, conformist sound become
ELPA MARKETING INDUSTRIES, INC.
normal. And the funnier will the rugged - may take awhile longer to sink in. But Dept. A-12 Ortofon Div. New Hyde Park, N. Y.
individualist speakers sound. Too bad, in there'll be no avoiding the trend. Gray In Canada. T,, -Tel Associates. Ltd W,Ilowdole. Ont.
flannel sound is IN. It is rapidly be a way. It is the end of an era.
CIRCLE 130
Elliptical Stylus
!
-
AUDIO
DECEMBER, 1964
.
57
www.americanradiohistory.com
AmericanRadioHistory.Com
coming NORMAL sound. The colorful
speaker of old, with all its assorted enhancements, mellownesses, brilliances,
presences, is on the way out via the
public's own ear, and that is that.
So, Mr. Maker, if your speakers are
noted for their distinguished individuality, you'd better join my gray flannel
club quick, the Sound -Alike Club. It's
getting less exclusive every day.
3. Novelties
I am certainly not going to throw
myself to the wolves at this point by
listing all the members of my Sound Alike Club, nor even its Associate Members, those who almost made the grade.
(You go listen, you decide for yourself
with your own excellent ears.) But, having for once been systematic via penciled notes on the hi fi show exhibits
that caught my fancy, I can't resist passing on a few items to you as novelties.
Strictly personal highlights-no room
for all my penciled notes, either.
(First note the way to cover a hi fi
show is to cross the fingers of your
right hand and point to the nearest
door on your right-right side of the
corridor. Enter-then get bacic out of
the same door, or you're lost. Continue
with fingers crossed until you complete
a circuit-then reverse engines and go
the other direction, on the other side of
the corridor. Never uncross those fingers and never shake hands. If you do,
you're a goner. Worked fine for meI visited every room in the New York
show, on four floors. But, alas, my
fingers are still crossed; they got stuck
that way after a couple of hours.)
At least two tape recorder exhibitors
did a simple show -trick this year, which
I recommend as both dramatic and informative. They set up a battery of
identical recorders each playing at a
different speed, and so marked in large
(buy Tarzian Tape three reels at a time!)
numbers. A switch allowed ABCD comparison of the sound. Crown's exhibit
was the trickiest, for they had big maThere are some sounds that you plan to preserve. You know in advance- chines running at 71/2, 33/4, 17/e. 15/16
"Here is something I will want to keep, permanently, on tape." You're ready and 5/16! All music, too. The 5/16 speed
sounded like a good telephone broadcast.
for. them.
The music scarcely wavered. Amazing.
:
Triple
your tape recording
fun
There are other sounds, though, that you can't predict or schedule. They
Marantz's sensational true -tracking
just come along, never to come again. Do you have an extra reel of tape on phono arm, the SLT-12, was the object
hand? Are you ready for the moment that cannot otherwise recur?
of my fascinated inspection. Being me, I
Why not take this good advice? When you buy tape, buy at least three reels.
And buy brand name tape, so you can be confident of its quality and certain
it won't harm your recorder.
Of course, we hope you'll choose Tarzian Tape. We thoroughly test other
brands along with our own-and the impartial equipment in our labs assures
us that you can't do better.
FREE: Our 32 page booklet tells you how to get more out of your tape recordings.
Write for your copy.
12
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World's Leading Manufacturers of TV and FM Tuners Closed Circuit TV Systems Broadcast
Equipment Air Trimmers FM Radios Magnetic Recording Tape Semiconductor Devices
BLOOMINGTON, INDIANA
MAGNETIC TAPE DIVISION
Export: Ad Auriemo, Inc.. N.Y.
Canada:
E. J.
Piggott Enterprises Ltd., Toronto, Ont.
CIRCLE 131
touched it and threw the thing off its
trolley for fair. (It was tracking a
violently eccentric single groove on a
shiny acetate disc.) This isn't the first
arm that manages to remain tangent to
the grooves throughout its play, but it
surely is the most ingenious mechanically. Put your fingers together as in
prayer, keeping them straight. Bring
the joined tips towards you, still touching. That's the principle (i.e., the pickup
travels in a straight line across the
record, like your fingertips). It works,
too, and soundly, for this mechanical
arrangement allows for great "lever-
AUDIO
58
www.americanradiohistory.com
AmericanRadioHistory.Com
DECEMBER, 1964
age" against the bearings (at your
wrists) and thus minimizes the drag
against the groove. But there are no
less than twelve bearings involved-I
counted them-and that's a lot. Nevertheless, the Marantz arm is one of those
honest jobs that anybody who has a
mechanical sense is bound to admire.
More power (and less friction) to Marantz.
The smallest speaker in the show was
a whiz, the tiny "Maximus I" from
Goodmans. It's slightly bigger than a
box of shredded wheat standing on end,
and a pair of them sound like something you won't believe. Hope to try
some later on. Smallish speakers are
making a big spurt this year and, natch,
virtually all of them are flaunting some
variety of "acoustic suspension." That
term now seems to mean any speaker
enclosure that doesn't have a hole in it,
not counting the speaker hole. We used
to call them infinite baffles. Some of the
new ones do, indeed, take advantage of
the soft-cone, big-air-spring system and
the results are understandably good,
here and there, if not always.
The new smaller "bookshelf" size listings are much enriched this year, with
significant items from many makers. I
enjoyed, very briefly, the KSC models,
the new KLH Model Seventeen and
(how we do run to initials !) the new AR 4; also the Sonotone Sonomaster RM -1
(not to be confused with E-V's quite
different Sonocaster, an outdoor waterproof carryable job).
All of these new smaller models are
of a size that really promote convenience
and a much -needed flexibility in stereo
listening, for they invite being moved
around-and we should move our speakers around to suit different sorts of recorded material. The sound, too, while
naturally compromised from absolute
perfection, is something we would not
have believed ten years ago. It can be
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done.
(If you still want your 30 cycles clean
and your 50,000 too at 100 watts, stick
to the monsters. They're still around, if
a bit shrunken in cubic footage.)
I was intrigued by Leak's "perfect
piston" sandwich, a speaker cone of
featherweight foam about a quarterinch thick, with two hard -faced silvered
surfaces. He passed out pie-shaped piece
of the stuff, one of which I have before
me. Nice. Fisher had an aluminum cone,
(partially) but I only saw it, didn't
hear it.
Then there was the inevitable upside
down record player-this time it was
Dual. I'll have something to say later
about the tendency to jar which is inevitable in these new feather -touch systems, even when upside down. Loose
floorboards don't like them. And then
there was the backwards tape recorder,
taking us straight back to the beginning
of home tape. Remember the ancient
Twin-Traxy It started the "half track"
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CIRCLE 132
DECEMBER, 1964
59
www.americanradiohistory.com
AmericanRadioHistory.Com
Featheirweighit
o
0
0
with a wallop
The KLH Model Sixteen is probably the smallest
integrated stereo amplifier in its power class.
We designed it that way. Small enough to fit into
any room. Handsome enough to be welcome there.
But small size and good looks are only the beginning. The Model Sixteen really delivers all the advantages of transistor design that you've been promised
for so long.
This is a full powered, full performance amplifier,
with 70 watts of wide -band steady state power
200
watts of peak power.
This is clean power
KLH clean. Distortion
-
...
levels are insignificant from 25 to 20,000 cps.
This is reliable power, far beyond the potential of
any tube amplifier. (There is no known aging process
in a transistor.) The Sixteen can't be shorted out or
burned out in use. A unique electronic circuit, designed
by KLH, eliminates the need for fuses or circuit breakers in the speaker outputs.
We saved the best for last. The price is a featherweight, too.
Just $219.95. The cabinet is optional at $19.95.*
That's less than you'd pay for one of those big
heavy old-fashioned jobs.
-
We designed it that way.
*Slightly higher on the west coast.
IIIIIIIIIIIIIIIIIIN1}IIIIIII11II
npCC
OSS
STR ETCAMBRIDGE 39, MASSACHUSETTS
system, playing frontwards, then backwards to the beginning. This year it's
Ampex and Viking who are doing it.
But the fatal flaw in the older reversible systems, the moveable head, is now
thankfully absent. The heads are fastened down to stay. You just have more
of them. Concertone's Reverse -o-matie
started the new trend awhile back; now
that Ampex has joined up, we'll probably be seeing a lot of mirror stuff in
the tape department. No more reel
changing for "Side 2" and a good idea
if you don't mind the added machinery
and the electronics. (If you do, you
can still buy the old turn -it -over kind.)
Trickiest speaker at the show was that
huge lampshade affair, big modern style vase lamp with the sound coming
direct from the lamp shade itself-an
electrostatic speaker. (Bass from the
lamp base.) Surprisingly, those lamps
really sounded pretty good. I'd enter
them in my Sound -Alike Club even on
brief audition, over people's craning
necks. The Acoustica Omnisonie 360better write that down 'cause you'll
never remember it. (Panasonic? Trusonic? Duosonic? Supersonic 'I Subsonic? ? )
Of course almost any virtuous electrostatic today sounds pretty good at
least in the upper end. Definitely within
sound -alike tolerances, by their very
nature JansZen's electrostatics were
still around and still sounding good; he
had a neat reflector to spread the sound
of a single electrostatic tweeter "cell."
Modest price on it. Pickering, alias
Stanton, was using one of the old Pickering electrostatics, the unit mounted
overhead on stilts with a woofer box
below; it sounded wonderful and so did
a new Stanton model in another room,
not yet in production. Acoustech has the
newest Janszen-designed monster, a pair
of door -sized full -range electrostatics
(like the KLH Nines) which will take
900 watts of audio out of built-in amplifiers. All you need is 1700 smackers.
How I do go on and on
room for
one more minor novelty; Sonotone's newest ceramic stereo hi fi cartridge,which
has two points, flipover-style, on a single
stylus and is provided with neatly miniaturized equalizers so that the thing
plugs right into any old magnetic input
for instant play. Ingenious and probably
sounds pretty good, too. Have to skip
all those marvelous 15 -degree magnetics;
but you'll hear plenty about them elsewhere.
My bet for the zaniest name at the
show-and no reflection on the product
itself-is the Cipher. That means zero,
or nothing. Now where do you suppose
they got that idea? It's a line of tape
recorders, and a lot more than nothing.
With that cipherous thought, I bid you
fair-well until next year's big show, for
...
1966.
CIRCLE 133
60
Æ
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
DECEMBER, 1964
RECORDS
(front page 48)
Variations on a familiar theme, the wellknown Paganini Caprice.
Jascha Zayde is the half of this team who
lavishes his musical skill on these elaborate
re -compositions. His style is marked on every
one of them, superimposed on the original
composer's ideas-Johann Strauss and waltz
music from "Die Fledermaus," the familiar
"Invitation to the Dance" of Weber, wellworn music by Rachmaninoff and Dvorak,
every piece scintillating In its two -piano
form, smooth as silk and glassy as glass,
sometimes pretty hard and brittle, more often
sparkling and light, and sometimes downright oily in sentiment.
It's as close as you can come to cafe candlelight music for two pianos ; but the classics
survive nicely. And Mr. Zayde's own variations on the Paganini theme, out-Brahmsing
Brahms, out-Rachmaninof&ng R., are exciting
to follow in their sheer exuberance of technique even though the slightly cream -puff
Zayde harmonies may give you musical indigestion.
.2E
AUDIO & HI FI
IN WEST GERMANY
Emendations and Additions
As might be anticipated, we made a few
minor errors in our article of this name in
the November issue-none of them earthshaking, but all correctable, as follows:
The DUAL people advise us that their
top lines are made in St. Georgen and
Messkirch, and the record players at a third
factory in Dunningen, and that their total
daily output of changers and record players
is 2600 instead of the 1600 we credited
them with.
We are sorry to learn that Mr. Oskar
Steidinger, who was Managing Director at
the time of our visit, passed away during
the first week of October.
Baron Hornstein of UHER tells us that
the company was founded by Count Toerring and his son, and not a younger brother, and he feels that apartments in Germany should more likely run from $40 to
$60 instead of the $20 to $40 we reported (maybe he's accustomed to living
in better apartments than we are) and that
$20 would be a more realistic figure for
Vienna (though Fritz Sippl of AKG OK'd
our $2 figure.) The Baron also counts 85
"roofs" at the Hanover Messe, whereas we
counted from the "map" of the grounds
only the 25 we reported-if it makes much
difference.
Mr. Paul Metz of METZ tells that now
a second FM program can be heard all over
Germany. ELAC now has an output of
750 record players and changers per day,
an increase of 50 over the 700 we said-an
indication of some growth in just the past
few months-and that Dr. Rudolph's (note
the corrected spelling) son is general sales
manager.
PERPETUUM-EBNER says we shortchanged St. Georgen's population-12,000
instead of 11,000.
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A genius, really, this OKI Tape Recorder, in creating sound
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The OKI is solid state, with 27 transistors. But absolutely no
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any other instrument of its kind. And yet the OKI costs less
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CIRCLE 134
AUDIO
61
DECEMBER, 1964
www.americanradiohistory.com
AmericanRadioHistory.Com
received was equipped with a Weathers
LDM cartridge, a ceramic unit which is
EQPT. PROFILE
(from page 51)
,
entire mechanism is mounted on a sub chassis which is spring mounted to the
motor plate with very flexible conical
springs. This sub -chassis also mounts the
moulded soft rubber arm base to provide
the required rigidity between arm pivot
and turntable center. The motor is on
a pivoted plate which allows the driving
puck to be lifted away from the turntable rim when the power switch is
turned off.
The walnut arm is provided with an
adjustable counterweight to permit setting the desired stylus force. The output
leads are in a flat cable consisting of two
shielded conductors and a separate
ground wire. The arm will accommodate
any conventional cartridge. The unit we
designed to work into a magnetic phono
input when used with the equalizers
provided.
Over-all performance shows wow and
flutter to be less than 0.1 per cent, and
rumble at - 43 db. Since the motor rotates at 600 rpm, most of the rumble is
in the 10 -cps range. Cartridge output,
with equalizers and feeding into a
magnetic input, is 1 my per cm/sec recorded velocity. Because of the extremely
flexible mounting of the turntable/arm
sub -chassis, the unit is little subject to
Mr. Canby's "loose floor board" treatment at stylus forces of 2 grams or more.
Priced at just under $60, with an additional $10 for the LDM cartridge, the
"Townsend" offers an opportunity to add
phono facilities to any system at a reasonable outlay.
Circle 213
Fig.
3.
Weathers
"Townsend"
Stereo Turntable.
MUSE ON TAPE
(from page 24)
channel their creative energy. Some directors are minor despots, controlling
actors as puppets on long strings. I have
a little more faith in humanity than
that. Bruno Walter used kindness and
consideration. . . . Fritz Reiner used
firmness if not fear; both men turned
out excellent work. Choose your weapon.
How much time should be allowed for
rehearsal and recording? If you're working with amateur actors (no union scale)
who have never seen the script before
(excluding read-throughs and character
development rehearsals) allow about
four hours for every fifteen minutes of
completed recording time. Allow 45 minutes to an hours worth of tape for each
completed 15 minute segment.
A play that's already been performed
can be done in less time. About an hour
for every fifteen minutes of playing
time. The actors can no longer move
about as they did on stage and will have
to practice the scene several times under
the new restrictions.
WARNING when making a take (a
section of a scene or an entire French
Scene) the actors must assume the same
positions for each take. Any movement
must he exactly the same. You have no
:
If the cardioid pattern is an essential con-
sideration in selecting
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24
Range: 30 to 18,000 cps (cardioid)
Range: 30 to 16,000 cps (cardioid)
Response: ± 2.5 db over entire range
Response:_ 2.5 db over entire range
Dimensions: "x4"
Data sheet available on request
Dimensions: 11" x 6"
Data sheet available on request
The AKG -C60, for its size, has an unsurpassed cardioid pattern-front-to-back discrimination is never
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These superb characteristics are ideal for difficult
acoustical installations, particularly concert halls,
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6-6d
CIRCLE 135
62
AUDIO
www.americanradiohistory.com
AmericanRadioHistory.Com
DECEMBER, 1964
idea how this can help in editing. If the
actors do not use the same position, and
you are forced to assemble a scene from
several takes, you may find actors
jumping from one spot to another after
the editing job.
Professional actors or advanced amateurs may be able to get away with half
the time, especially if they have worked
with you before.
A SURVEY OF RECORDING AND BROADCAST
ENGINEERS IS THE SECRET BEHIND THE NEW
ALTEC 470A AMPLIFIER & 550A POWER SUPPLY
Some Minor Points
Before we did anything else, we surveyed
Have plenty of tape on hand, same
brand, same thickness and backing type.
This will avoid changes of hiss or recording level. (I like 1 -mil polyester myself,
I bulk erase it before use just to be
sure.)
2. Sound effects can be done by the actor or a sound man at the time of the
recording. Recorded effects may have a
different acoustic environment.
3. Continuous sound effects
(car,
train, rain storm) are probably best rerecorded (dub) and added after the final
editing. Any editing with a continuous
background effect may "jump" at the
point the editing is done.
4. If a plane or car makes extra noise
outside the studio during a take, stop
the recording but not the recorder, and
go back to a point where the actors
paused.
5. Make several takes of each scene.
DO NOT ERASE ANYTHING. This
may be expensive in tape, but it's hard
to assemble a cast again if something's
missing or not available in a reasonable
form.
6. If an actor blows a line (makes a
mistake) have him stop and go back to a
point where he paused in the speech and
start again.
7. Use 71/2 or 15 ips tape speed if
music is a vital part of a performance.
Most voice recordings can be done at
3% or 71/2 ips. Absolutely use 71/2 ips
if you must do any editing.
8. Do not record any material in
copyright. You cannot sell that material
without violating the law. Material for
use in classroom exercises can often be
recorded. Memories recordings, not sold
(they can buy the tape, and give you a
beer I suppose) may be illegal, but you
may not get caught.
9. Editing the play can be as creative as recording it . . but that's another story.
I couldn't get ten commandments but
like Casca in "Julius Caesar," Act I,
Scene II: "There was more foolery yet,
if I could remember it."
Engineers reading this article may
give up at the aestheics, directors give up
on the engineering. If there is anybody
left: go back. An engineer who does not
understand theatre will probably do a
poor job. A director who does not have
some familiarity with recording technique limits his artistic approach. So go
back, both of you!
engineers. Guided by the results, we built
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An all solid state device, the Altec 550A
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under the full 2 amp load.
NO SACRIFICES FOR THE
SAKE OF MINIATURIZATION
Most of you felt that miniaturization had
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is slightly larger than some "subminiature"
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size difference you requested will help with
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larger "plug-in" connectors simplify wiring and circuit tracing; easier to connect
and solder. Its sensible size makes it easier
to maintain and service, too. On top of
that, the Altec 470A Amplifier has a lower
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designed for this function. And, it excels
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CHECK THESE SPECSYOU'LL LIKE THEM:
GAIN: 45 db (input terminated); FREQUENCY
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DISTORTION: Less than 1% THD, 20-20,000
cps, with +27 dbm output; NOISE LEVEL
(unweighted, 10 cycles to 25 kc band-pass):
Equivalent input noise, -127 dbm (input unterminated); OVERLOAD RECOVERY TIME: 5
micro -seconds for 100% overload.
ACCESSORIES:
ALTEC 850A AND 852A TRAYSNeeded for mounting 470A and 550A
whether in rack, console or bench use.
Gold-plated receptacle permits instant
plug-in of amp or power supply.
ALTEC 800A MOUNTING FRAMEAccommodates up to eight 470A Amplifiers in 850A Mounting Trays or a combination of amplifiers and power supplies.
Now in production! Altec new 61A
and 63A Program Equalizers and
three variable filters: 67A high and
low pass, 68A low pass, 69A high
pass will be ready for delivery soon.
Write for complete specifications.
For Technical Literature or Ordering Information, Write to: AUDIO CONTROLS DIV.
ALTEC LANSING
A[TE[® CORPORATION
LANSING CORPORATION
A Subsidiary of Ling-Temco-Vought, Inc.
01964 ALTEC LANSING CORPORATION
ANAHEIM, CALIFORNIA
Circle 136 on Reader Service Card
AUDIO
DECEMBER, 1964
63
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AmericanRadioHistory.Com
HERMAN BURSTEIN
LeivUi'ely taped
on the fah111011
t
88 STEREO COMPACT
Choice of Music -Lovers and
Music -Makers.
Features exclusive "EditEze" cuing and editing.
Superb 30-18,000 cps frequency response for finest
mono or stereo recording
with three hyperbolic heads.
Monitor -off-tape, Sound on
Sound, Erase-Protek, automatic shut-off, tapelifters,
are but some of the many
features to let you thoroughly enjoy high quality tape
recording.
4 -track model
2 -track model
Walnut enclosure
$339.95
$347.95
$ 15.95
For portable model with
speakers ask to see the
"880."
MADE BY SKILLED
AMERICAN CRAFTSMEN AT
ing
OF
MINNEAPOLIS, INC.
9600 Aldrich Ave. So. Minneapolis, Minn. 55420
CIRCLE 137
(Note: To facilitate a prompt reply,
please enclose a stamped, self-addressed
envelope with your question.)
Tierman Burstein
280 Twin Lake E., Wantagh, N. Y.
Improving Preamp Gain
Q. I am feeding the signal from my tape
playback head into the tape head input of
a Lafayette KT -600 preamp, and from the
output jack of this preamp into stereo
headphones with a rated impedance of 200
ohms. But I don't get enough gain from
the preamp to drive the headphones adequately. What measures may be taken to
increase the preamp gain?
A. The KT -600 has an output impedance of about 1500 ohms, so that there is
a rather bad mismatch with your 200 -ohm
headphones. The KT -600 uses an anode
follower at the output, and you could reduce the output impedance by increasing
the feedback of the anode follower; or else
by redesigning the output stage to make
it a cathode follower, with a resultant
impedance of about 500 or 600 ohms. However, this does not assure that you will
have enough signal output. The KT -600
has several stages incorporating feedback
for the purpose of shaping frequency response and keeping distortion to a minimum. If you know your way around, you
could reduce feedback in one or more
stages to get higher gain. At the same
time you would have to be careful to
avoid a large increase in distortion or undesired change in frequency response. Your
best solution may be as simple as getting a
suitable matching transformer for your
headphones. Inquire of your audio dealer
or of the microphone manufacturer.
Bias Adjustment for 3 -Head Machine
Q. I have a machine with separate
record and playback heads that permits
instantaneous monitoring. What is the
procedure for adjusting bias?
A. The typical procedure for such a machine is as follows. Using the manufacturer's recommended frequency (usually
between 1000 and 3000 cps), feed in this
frequency and adjust bias for maximum
playback output. Continued to increase
bias until the output level falls about 0.5
db. Cheek record -playback frequency response in the region between 10,000 and
15,000 cps, using 1000 cps as a 0 -db reference. If the upper treble response differs
by more than 2 or 3 db from flat, adjust
bias; increase it if treble is excessive, or
decrease it if treble is insufficient. Alternatively, if the machine contains variable
record equalization, you can leave bias
alone after adjusting it on the basis of a
frequency between 1000 and 3000 cps, and
adjust the record equalization for flattest
response. Another alternative, if treble re-
sponse is excessive, is to increase bias so
long as this reduces distortion.
Recording Lectures
Q. I require a tape machine principally
for recording lectures (about two hours).
I assume I need a quarter -track machine
which will operate well at 3.75 ips. I am
slightly baffled by frequency response specifications. Thus one unit I am considering
is rated at 40 to 15,000 cps, while another
model of the same manufacturer and
nearly the same in price is rated at 30 to
20,000 cps. I am also baffled by signal-tonoise specifications and comparing one
machine with another in this respect.
Please clarify.
A. Unless the frequency response specification states the deviation from flat response in terms of decibels, it is difficult to
compare one machine with another. Thus
the machine rated at 40 to 15,000 cps may
be flat within 3 db over this range, whereas
the machine rated at 30 to 20,000 cps
(probably at the urging of the advertising
department) may also be fiat within 3 db
only between 40 and 15,000 cps.
In comparing signal-to-noise ratio of
various machines, one has to be very careful about the recording reference level.
Among quality manufacturers of tape
machines, the reference is customarily the
recording level at 400 cps which produces
3 per cent harmonic distortion on the tape.
Some machines are rated instead on the
basis of 5 per cent distortion, and some on
the basis of 1 per cent; in the former instance you should subtract about 6 db from
the claimed ratio, and in the latter instance
you should add about 6 db.
1/4 -Track Head
playing a half-track tape with
a quarter -track head result in deterioration of potential signal-to-noise ratio?
A. The half-track recording's signal-tonoise advantage lies in the greater amount
of signal recorded on the tape. Thus, compared with quarter -track recording, more
signal is presented to the tape playback
amplifier, resulting in a higher ratio between the playback signal and noise of the
playback amplifier. If a quarter -track playback head is used, which cannot span the
full width of the recorded track, the potential advantage is lost. On the other
hand, some of this loss can be regained
if the quarter-track head is of extra -high
impedance, resulting in augmented signal
output. At the same time, extra -high
impedance carries the threat of high frequency loss due to the filtering action
of the head inductance in conjunction with
capacitance across the head (winding capacitance, cable capacitance, input capacitance of the tape amplifier).
Playing
1/2
-Track on
Q. Does
AUDIO
64
www.americanradiohistory.com
AmericanRadioHistory.Com
DECEMBER, 1964
Inside Audio
LARRY ZIDE
The Editor has asked me to undertake
the job of filling this space with a
column devoted to the broad subject of
the high fidelity components industry.
I was happy to accept because there is
a great deal to say about this unusual
group of manufacturers, their concepts,
their ideas, and, on occasion, their
dreams.
But this will not be a chit-chat column.
No sir Unless there is some relevancy,
you will never find out here that Joe
Doakes moved from here to there, or
that he's just come out with a fifth revision of his product (which didn't really
need it, anyway).
What this space will be is a forum for
new ideas, different solutions to old
problems, and the discovery of new
problems. In general, any subject that
is of broad interest within the framework of audio componentry, and allied
fields, will be fair game for my typewriter.
There is an old cliché that is usually
included by every new columnist. It says,
in effect, that this will be your column
(dear reader), so write and tell me what
you want. Not quite so.
I am just selfish enough to say that
this will be my column and I intend to
remain my own master. But don't think
that I will turn a low -fi ear to criticism.
Far from it. I do want to hear from you
when you think I'm correct and when you
think I'm all wet. And, guided by the
precepts of this column, I will welcome
suggestions for topics you want to hear
about. The coming months will be ones
of exploration for a raison d'être of
this column. Needless to say, your interest, and its expression, will play a
pivotal role.
1
The Expendable Word
Not too long ago, I spent several days
wandering the halls of the New York
Trade Show Building, where four floors
were taken up by an annual rite called
the New York High Fidelity Show. It
formerly was called the NYHF Music
Show. Apparently the title was much
too cumbersome, so they decided to
drop the expendable word.
Anyway, some 60 -plus components
manufacturers occupied rooms spread
over four floors of the building. And
spread is the correct word. I have never
AUDIO
seen, in the many years of attending this
observance, so many unused rooms.
True, the empties were carefully distributed to minimize the arid effect, but
the bottom floor (third floor of the building) apparently was too much of an
exercise in camouflage for the management, it was very obvious. Missing were
such one-time stalwarts as Altec-Lansing, Heath, Jensen, and Lafayette, to
name just a few. And also missing were
all of the record companies, once a sizeable contribution to the space occupied.
(Is that the reason that they dropped
Music ? )
But something else, something more
important, was missing. The feeling of
enthusiasm, of excitment. Almost every
room gave the feeling of tiredness. Perhaps that was because the crew had just
spent a hectic 4 hours setting up the
room. Perhaps it was because they knew
in advance, whether they admitted it or
not, that there *as far more effort put
into this kind of show than was gotten
out.
The High Cost of Shows
A manufacturer pays the high cost
of show participation out of advertising
allotments. The irresistible laws of economics state that you must receive a
return on your investments if you are
to stay in business. In short, you must
produce more than a good product, you
must make a profit.
But, does a show, such as this one,
give more than it takes? Most manufacturers will admit, privately, that it
does not. Yet, habit, more than anything
else, compels them to come back for this
annual beating.
Who actually goes to a high fidelity
show? Certainly, people interested in
components. Some of them may even be
interested in the purchase of components.
But for the manufacturer to get his
money's worth, he must reach more than
some who are actively in the market for
merchandise. Compounding these economics is the fact that attendance has
been shrinking over the past few years.
This balanced against efforts to expand
the market for components, raises, of
itself, grave doubts as to the efficacy of
presently constituted audio shows.
Previously, up to a few years ago,
the shows served the purpose of stimula-
DECEMBER, 1964
Ií; a ma,fierpiece!
RETRO-MATIC 220
Exquisite quarter track
tape recorder for dedicated music connoisseurs.
Bringing hours of immeasurable pleasure to
true music lovers, the
Retro-Matic 220 sparkles
with practical features (not
superfluous gimmicks).
Three-way reverse play,
four heads, three motors
(HSM capstan drive),
"feather -touch" pushbut-
tons with optional remote
control, two speeds,
records and plays mono or
stereo with 20-25,000 cps
frequency response.
Your Retro-Matic 220
will reward you with exciting performance and, by
virtue of its unique versatility, provide you with
techniques for the modern
concept of tape recording
now and in the future.
Solidly engineered and
meticulously made by
SKILLED AMERICAN
CRAFTSMEN
for $860.00
ing
OF
MINNEAPOLIS, INC.
9600 Aldrich Ave. So. Minneapolis, Minn. 55420
CIRCLE 138
65
www.americanradiohistory.com
AmericanRadioHistory.Com
tion for the future buyer. These shows
used to crawl with the hobbyists, the
kids, the customers for the next five
years. But they seemed to be absent this
year. Is it partly because the cornpenents industry has outgrown its hobby
customers? Let us hope not. There is a
large, and as yet, untapped market
among music enthusiasts per se (after
all, what is all this equipment for, if not
the reproduction of music) and they are
the bulk of the future market, but the
hobbyist remains the backbone. Break
him, and the skeleton will collapse.
But to put meat on the bones, the
music listener market must be the target
of attack. At this stage, I doubt that
anyone really denies the sonic superiority of components over the bulk of the
packaged goods, but what is being done
to get this message across? Is the large,
expensive audio show (designed primarily for insiders) the answer?
The inescapable conclusion that must
come from observations of this scene is
manifestly clear. The great, centralized,
and high-priced product exposition has
grown obsolete in terms of the type of
customer it attracts and, for that matter,
fails to attract. But product expositions
IVE
HE
IM-P11.01
EXCUS
OMA
USINE AKUS
1E`
IPA
1HE EXC` 800o By MAR
AND
ANN A
are, of themselves, not wrong. What is
needed, and desperately so, are smaller,
more regional, shows. It must be made
possible for more people to get to see
the components and talk to experts who
are capable of conversation with lay,
semi-knowledgeable and hobbyist groups.
Selling the concept of componentry
should be the aim, not selling the sound,
at best a confused jumble at these shows.
I dare say that few components have
been sold, solely on the basis of how
they sounded at a show.
It is time, I believe, for organizations
such as the Institute of High Fidelity,
that NAM of componentry, to sit down
and indulge in some self-examination on
this whole question. I for one, will nostalgically miss the big shows, but for
the health of the industry, I believe they
must go.
AUDIO CLINIC
(from page 2)
FRO MHEUHER
poorly and your neighbor's tuner works
well is that he is using a poor antenna
and a tuner with a less critical front end.
If you were to take his tuner and your
tuner and place them side by side in a
fringe area, your tuner would out -perform his. It might well be that you would
be better off obtaining an old tuner with
adequate sensitivity to bring WBAL and
little more. Almost any tuner should be
able to pull in signals 40 miles away.
This might sound like taking a step backward, but it really is not when you consider the other factors in your particular
case.
The only other thing I can suggest is
that you disconnect your present antenna
system from the tuner and connect a
short length of wire to the rear terminals.
All you need use is one terminal. Perhaps
this arrangement will make it possible
for you to pick up WBAL reasonably
well. The antenna, being very poor in
performance, will attenuate the strength
AND ALL YOU'RE LEFT WITH IS
A GREAT PROFESSIONAL TAPE RECORDER
WITH 100 OTHER USES.
The Uher Royal 8000 represents one of the finest and most versatile tape recorders to be offered
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4 track mono recording and playback, synchronous sound with sound recording, multiplay sound
on sound and echo effects. Plus: Exclusive Dia-Pilot-Built-in
impulse transmitter for fully automatic control of slide
projector and animated displays. Exclusive Akustomat-you
you stop speaking
simply speak and the machine records
-machine stops. Audio Magazine stated: "practically any use MARTEL ELECTRONICS
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of all signals, and might thereby permit
your front end to operate normally.
WBAL may provide sufficient strength
to be heard with this antenna. It's certainly worth trying before discarding
your tuner.
Transient Clicks
Q. For a couple of months now, while
listening to a program on disc or tape,
there occasionally comes from the speakers a very sudden and sharp single crack
like that of a rifle shot. Perhaps it can
be more appropriately described here as
a kind of static or capacitive spark dis-
charge somewhere, amplified and fed into
the speakers. Also, the sound is not necessarily of the same intensity each time,
and it seems to be quite independent of
the volume control setting. It has even
AUDIO
66
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AmericanRadioHistory.Com
DECEMBER, 1964
been known to occur when nothing at all
was being played, such as when a record is being changed.
This effect, coincidentally or otherwise
was first seen to occur at the onset of
winter. I was thus led to believe that air
dryness resulting from indoor heating
created static somewhere, somehow. I
grounded all components to earth by way
of a heavy lead to a waterpipe or heating radiator. There was no apparent effect, or lessening of the fault.
In consideration of the fact that the
source of this "bug" might well be the
a.c. power line itself, may I mention
that I live in an apartment, one of eight
in a single unit. The cause could be the
starting up of a refrigerator or other
appliance or perhaps even an intermittent shorting or defect in the main wiring somewhere, resulting in abrupt line
surges. I state this because I have, at
times, noted a sudden dimming of the
room lights, the instant that the offending "crack" sounded from the speakers,
a dimming such as is common when an
appliance is switched on, although, of
course, I have not been able to determine
whether one phenomenon causes the
other or is the result of it. John P.
Wright, Montreal, Canada.
A. I definitely rule out static as the
cause of your difficulty. I have known of
instances where static electricity builds
Boni let
a "STEREO -DEAF" FM
up on moving tapes, discs, and turntables. However, you have indicated that
the "crack" can be heard when nothing
is playing. I have not known static to
cause interference to audio systems
from any other cause.
I suspect that the trouble is caused
by the transient created along the power
line when the furnace ignites. If it is
not the furnace, it is probably a refrigerator. The fact that the lights dim
down at the time the transient is heard
indieates a substantial drain along the
power line.
It is probably the transient nature of
the voltage demand which causes the
noise in your system, rather than the
drop in voltage. The problem then resolves itself into how to eliminate the
transient condition from your equipment. There are on the market some LC
filters which are designed to be placed
between your amplifier and the line.
Possibly such filters can eliminate your
trouble. I am not altogether confident
that their use will help.
It is far better to get right to the
source of the trouble and eliminate the
problem there. A capacitor -resistor combination placed across the contacts of
the thermostat or probably better yet,
across the relay contacts which actuate
the burner motor might be successful.
An effective filter can be made using
a 0.02µf capacitor placed in series with
200 ohms. The capacitor should be rated
at 1 kv and the resistor should be rated
at two watts. This combination is then
placed across the switch contacts of the
offending appliance. The addition of this
combination will not impair the performance of the appliance.
A refrigerator is harder to correct
because of the inaccessibility of the
thermostat and the relay (if the refrigerator happens to use a relay-some do).
I do believe that the furnace is most
likely the culprit because the onset of
the problem concides with the onset of
winter.
I have seen some cures effected by reorienting leads in the preamplifier so as
to keep them away from a.c. power lines.
Sometimes bypassing each side of the
line to the chassis helps. 0.02 µf is probably a good choice for such a purpose,
rated at 600 v.d.c.
In my previous apartment I used to
have this trouble and I just had to live
with it. The furnace was responsible
first, but was added to by some old refrigerators whose thermostats needed to
be replaced. In my case, however,
grounding of the music system components did help somewhat, but not
enough for my liking.
Has any reader completely solved a
1£
similar problem?
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The all -new JFD LPL-FM antenna is log periodic engineered to give you the clean
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Write for the technical specs, charts, patterns' JFD ELECTRONICS CORPORATION
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and data that tell all.
Circle 140 on Reader Service Card
AUDIO
67
DECEMBER, 1964
www.americanradiohistory.com
AmericanRadioHistory.Com
BUYER'S GUIDE
ELECTRONIC ORGAN TONE COLORING
TO COMPONENTS
(from page 35)
TRADING
air -organ sounds.
These approaches give the organ purchaser a tremendous freedom of choice
of organ sound when selecting an electronic organ.
Before closing, we might add a word
about devices that have been designed to
ments over
tially as they are required. In pistons,
groups of stops are operated as one, so
that effectively the stops are ganged.
A relatively simple device is used by
Kinsman for this purpose-a punched
card programs the stops when the card
is inserted. (See Fig. 12) .
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UDIO
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TRADING ORGANIZATION
xcHanGeo
hasten the mechanics of picking up stops
during rapidly played passages. The
Crescendo pedal will be discussed in detail in a later article. Here we will only
say that it is a mechanism for picking
up stops in a programmed manner. A
foot operated cam engages stops sequen-
This completes our discussion on tone
generators and tone -shaping networks.
In the next article,
we will discuss techniques and devices for modifying the
sounds we have discussed and means for
generating special sounds.
To BE CONTINUED
PLEASE MAIL ALL ORDERS AND INQUIRIES TO JAMAICA
153.21 Hillside AR.., Jamaica 32, N. Y. Deal Al2 Mel 7.7577
WHITE PLAINS, N. Y.
203 Mamaroneck Are.
BROOKLYN, N. Y. MANHASSET, N. Y.
Elation Ave. 451 Plandome Rd.
RCA VICTOR "DYNAGROOVE"
1065
PLEASE SEND ME FREE BOOKLET
NAME
SYSTEM
ADDRESS
CITY
(from page 46)
STATE
J
CIRCLE 141
IF YOU ARE
MOVING
Please notify our Circulation Department
at least 5 weeks in advance. The Post Office
does not forward magazines sent to wrong
destinations unless you pay additional postage, and we can NOT duplicate copies sent
to you once. To save yourself, us, and the
Post Office a headache, won't you please
cooperate? When notifying us, please give
your old address and your new address.
Circulation Department
RADIO MAGAZINES, INC.
P. 0. Box 629, Mineola, N. Y.
geometrical configuration of the cutter of
Fig. 18. A major portion of this difference in angles may be attributed to bending of the recording stylus resulting
from the drag force produced by the
record material being removed from the
groove as shown in Fig. 20. A minor portion of the difference in tracking angle
disparity may be attributed to longitudinal lacquer springback. The two effects introduce essentially the same type
of tracking angle deviation.
The tentative standard angle for stereophonic disc records is 15 degrees. Accordingly, a suitable nominal geometrical tilt
angle was introduced in the Wextrex
Recorder and other modifications of the
cutter were incorporated so that an effective angle of 15 deg. was cut in the
master record. The "Dynagroove" rec-
ords are cut under this standard condi-
tion.
Lacquer Original Recording Console
A recording console has been designed
for recording the lacquer original from
the submaster tape. The submaster tape
is recorded in a manner designed for
transfer to the original lacquer record
without any appreciable modifications
except for that introduced by the Dynamic Styli Correlator. Therefore, the
manual controls are comparatively simple. The lacquer original recording console includes the Dynamic Styli Correlator and Recording Overload Indicator.
The Recording Overload Indicator is included to check on the signal applied to
the lacquer record.
AUDIO
68
www.americanradiohistory.com
AmericanRadioHistory.Com
DECEMBER, 1964
Disc Record
The minimum number of, but nevertheless significant, steps between the
original lacquer and the final disc record
are depicted in Fig. 1. Studies of the
plastic for the production of the dise
record has been carried out in a joint
research program with the manufacturer
of the plastic. One significant development has been the new revolutionary
electrical conducting plastics' which
helps to keep the record dust free and
thereby reduces surface noise. Everyone
is familiar with the attraction and accumulation of dust on conventional records due to the tremendous electrostatic
charges and resultant voltages developed
on the surface of the records. As a result
of the research and development in the
production of records, the signal-to-noise
ratio of the surface of the commercial
"Dynagroove" records is now more than
65 db.
Reproduction of Sound from
"Dynagroove" Records in the Home
In the Radio Corporation of America
there are many listening rooms which
simulate the acoustic of living, recreation and music rooms in homes. These
are located in the RCA Laboratories,
RCA Victor Record Division, the RCA
Victor Home Instruments Division, the
Broadcast and Communications Division
and the National Broadcasting Company. All of the listening rooms are
equipped with disc record reproducing
equipment of high quality termed "reference sound reproducing systems."
The turntable used is the RCA BQ-2C.
The wow and flutter are less than 0.25
per cent peak -to -peak.
The pickup is the RCA MI 11866-7.
The response frequency characteristic is
uniform to within ± 1 decibel from 30 to
15,000 cps. The crosstalk separation between channels is more than adequate to
insure stereophonic sound reproduction
with good auditory perspective.
The amplifier used in each channel of
the system exhibits less than 0.1 per cent
nonlinear distortion up to 20 -watts output. The response is uniform to within
a fraction of a decibel over the frequency range of 30 to 15,000 cps.
The loudspeaker mechanism used is
the RCA LC1A mounted in the RCA
LS11A cabinet. The design of the cabinet
has been carried out with the objective
of reducing the deleterious effects of difraction. The response is very uniform
from 30 to 15,000 cps. Another important loudspeaker characteristic in stereophonic sound reproduction is the directivity pattern, which should be independent of the frequency over the listening
area in order to provide faithful audi31 G. P. Humfeld, "Control of Static
Electricity on a Phonograph Record,"
Journal of the Audio Engineering Society,
Vol. 10, No. 4, p. 290, 1962.
AUDIO
EICO
DRIVING
FORCE
HI-FI
are to be found at your EICO distributor who
offers you a wide selection of professional quality EICO high fidelity equipment. Buy it
in semi -kit form to save money and at the
same time become familiar enough with it to
service it yourself. Or, you can still save money
by buying factory -wired EICO products with the
assurance you are getting the best Hi-Fi value
at any price. Complete EICO line of tuners,
amplifiers,speakers and tape recorders headed
by the new solid state 3566 FM-MPX automatic stereo tuner/amplifier.
-.---DIRECTION
OF GROOVE
TRAVEL
3566 SOLID STATE FM MPX AUTOMATIC
STEREO TUNER/AMPLIFIER.
Fig. 20 Diagram showing the geometrical axis and effective axis of rotation of
a stereophonic disc recorder.
tory perspective. Over a total angle of
90 deg. which covers more than the listening area there is no significant frequency
discrimination due to the directivity
characteristic. The nonlinear distortion
is another important loudspeaker char-
Finest all -transistor kit value, equal to $500-600
class instruments. Kit comes with pre -wired and
prealigned RF, IF & MPX circuit boards plus
transistor sockets. Outstanding 2 UV IHF sensitivity, automatic FM stereo -mono switching,
muting, 40 db FM stereo separation. Total 66
watts IHF music power, only $229.95 semi -kit
(recommended to beginners!); optional walnut
cabinet $14.95-also $349.95 factory wired including cabinet.
acteristic. As mentioned in the section on
the Dynamic Spectrum Equalizer the
peak sound level of reproduction in the
home is 80 decibels. The RCA LC1A
loudspeaker will deliver sound levels of
2536 FM MPX STEREO TUNER/AMPLIFIER
80, 90 and 100 decibels in a typical liv- combines
superb-FM-MPX
a
stereo tuner
0.05,
with a virtually distortion -free 36 -watt stereo
ing room for electrical inputs of
amplifier.
Kit
$154.95, wired $209.95.
0.5 and 5 watts respectively. For all of
70 70 -watt integrated stereo amplifier kit
the inputs the nonlinear distortion above ST
$99.95, wired $149.95.
150 cps is a fraction of a per cent. If
the distribution of the components in
1111111111111111111111111".6.-t
music with frequency are considered the
resultant distortions will be imperceptible even for a level of 100 decibels.
In addition to the subjective tests on
40 40 -watt integrated stereo amplifier kit
the reference equipment both objective ST
$79.95, wired $129.95.
and subjective measurements were also
FM/MPX STEREO TUNER Ultra -sensitive
carried out on all manner of commercial ST97
tuner for use with external stereo amplifier.
phonographs again with the main ob- Kit only $99.95, wired $149.95.
jective in mind.
The general conclusion was that the
original objective has been achieved,
that is to provide the listener in his home
environment with sound reproduction
which exhibits the highest order of artistic and subjective resemblance to that of
the live rendition.
Acknowledgments
The "Dynagroove" concept was ini-
12 -watt Hi-Fi system HF90A FM tuner, kit $44.95,
wired $69.95. HF12A amplifier, kit, $39.95 wired
tiated, developed, directed and imple- $59.95. BOTH for only $84.90 kit, $119.90 wired.
mented by George Marek, Vice Presi- RP -100 solid state
-track stereo tape
dent, RCA Record Division. In a project 4recorder
deck Top proof this magnitude it is impossible to list fessional quality
3 high
3 -motor drive
all who contributed to make it a success. performance heads.
Kit
Those intimately concerned with the ar- only $299.95, wired
$450.
tistic elements and tasks of the "Dynagroove" project include: John Pfeiffer
Ì
and J. A. Somer of the RCA Record
EICO Electronic Instrument Co. Inc.
131.01 39th Avenue, Flushing, N.Y. 11352
Division. Those intimately concerned
A-12
Send new 1965 catalog featuring
with the scientific elements and tasks of
more than 230 EICO products
the "Dynagroove" project include: R. L.
McClay, H. E. Roys and D. L. Richter
Name
of the RCA Record Division and J. G.
Address
Woodward, John Volkmann, E. C. Fox
Zip
State
City
Add 5% in West
and R. W. George of the RCA Laboratories.
CIRCLE 142
-
69
DECEMBER, 1964
www.americanradiohistory.com
AmericanRadioHistory.Com
SOMETHING
MISSING?
YOU
BET THERE IS
... THE
ABOUT MUSIC
(from page 14)
POWER
SUPPLY
!
In fact the new SYNCRON AU7a condenser
microphone has completely eliminated the inconvenience of a bulky power supply. The latest in
solid state devices (no RF circuitry) coupled
with advanced battery technology has finally
brought about a truly self contained condenser
microphone, requiring only an inexpensive and
simple battery change every two years (under
normal operating conditions). A rugged, dependable instrument with a frequency range of
30-18000 cps, cardiod pattern, low noise single
transistor amplifier with a switchable balanced
output of 50 or 200 ohms, it is equal to the most
exacting professional standards of sound pickup,
yet within the price range of the perfection seeking amateur.
MODEL AU7a ... $169.50 complete
Available immediately from stock.
For detailed information and specifications
write, wire or phones
SYNCRON
CORPORATION
10 George St., Wallingford, Conn.
Phone -Area Code 203/269-1822
CIRCLE 143
3 SPECTACULAR
SPEAKER SYSTEMS
That Defy Comparison in Their Class...
KSC-3
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Startling 360° "big system" sound of unbelievable quality and
incredible realism emanating from a handsome unit only slightly
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sound reproduction, like nothing you ever heard outside a concert
hall! This unique new KSC-3 system introduces a new speaker
concept, scientifically devised in this country, that provides
gigantic, spacious performance of magnificent full range quality
at an almost unbelievable price. Three superb speakers manufactured by SEAS of Norway* ... front mounted woofer, plus
adjustable mid -range and tweeter units radiating 360°, carefully
matched in an ingenious, revolutionary device (patent pending),
surround you with the most realistic stereo reproduction you ever
heard ... it defies comparison. Exclusive record for balancing
speakers included. See it, hear it, and be amazed!
Fabulous KSC-1 Superb!
Hit of the 1963 Hi-Fi Show! Now recognized by experts as by far the most
.
Larry Zide, in
satisfying performance available at a moderate price.
The American Record Guide says, "The KSC-1 is easily the finest speaker in Its
price class that I have heard
smooth -as -silk frequency response
equal
best speaker buy
to anything in the reproduction of the human voice
under $200, etc." American built 3 -way system with 3 magnificent speakers
Net $100
from SEAS of Norway*. 12" x 121/2" x 20".
...
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Low Cost KSC-55 Extraordinary!
A superior speaker for the minimum budget, for use in the finest monaural or
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15,000 cps. Incorporates a superb wide range 10" coaxial speaker of radical
new design, made by SEAS or Norway*. Hear for yourself how completely satisNet $55
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*We are Exclusive Distributors of SEAS speakers in the U.S.A.
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KSC SYSTEMS, INC.
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KS/Çeos DIVISION
crooked his left index finger, beckoning for more, and the trumpets immediately obliged with a shade more level
on the second phrase. The clarinet
melody beginning in bar 401 was a
decibel or so too loud, and phrased with
not quite enough pliancy; Solti tilted
his chin in the direction of the clarinet, made a curvy movement with his
left hand, and brought about a reduction in level and a smoother legato. It
should be pointed out, of course, that
most of Solti's indications merely remind the players of instructions given
during rehearsals.
At the other end of the dynamic spectrum, Solti aimed his arm at the brass
in a rapier thrust, and the brass attacks hit the ear with thrilling force.
And to produce a major crescendo, Solti
would lower both arms to his waist, then
raise them gradually, as if lifting a
massive stone. One could hear the players translate Solti's pantomime into
aural terms.
Always in motion, Solti seemed to
think of as many different movements
as the nuances he evoked from his complex instrument. He was a tennis player
negotiating a deft forward stroke, a
juggler balancing a vase in the palm
of his hand, a violinist with his finger
quivering in vibrato, a fencing master
lunging toward his opponent, a forester
swinging a huge ax, a cat clawing at a
sofa, or a frugue dancer at a discothèque, jerking his head and elbows.
To the layman, it might have seemed
as if Solti performed his podium dance
exclusively for the audience; none of the
players appeared to pay much attention
to him. Orchestral musicians, however,
develop amazing peripheral vision,
which enables them to keep both the
score and the baton in sight. "It's as if
we had another pair of eyes in our
scalps," a bassoonist put it. What about
the dance itself, the layman might ask;
is the conductor merely acting out the
musical score for his own pleasure'? According to the English conductor-author, Frederick Goldbeck, "dancing gesture stands paramount as a means to
make the players dance with the maestro
-that is, express the music as he wants
it to be expressed."
For well-balanced sound, avoid the
front rows at an orchestral concert, by
all means. But if you're forced to sit up
close, you might have a good time, provided the conductor's mobile and you're
1£
not sitting directly behind him.
New York 2, N. Y.
CIRCLE 144
AUDIO
70
www.americanradiohistory.com
AmericanRadioHistory.Com
DECEMBER, 1964
New!
WEBCOR
professional
COMPRESSOR
(from page 20)
Now you can fully utilize the listening capabilities of your audience! Scientists for
years have investigated and tabulated the
various phenomena that make people want
to listen. These findings come under the
broad category of psycho -acoustics. Now
Fairchild has harnessed many of these
findings and incorporated them into a line
of unique world -renown audio control
devices which produce a sound easier to
listen to and easier to perceive... in short
a bright, crisp, lively sound which keeps
your audience listening. This is the sound
you need to help you sell your station to
your audience and to your sponsors.
THE DYNALIZER
the Psycho -acoustic way to achieve a bright, full
bodied easy -to -listen -to, easy -to -perceive station
sound. The Dynalizer contours your station's frequency response to fully utilize the listening capabilities of your audience. Makes your station
sound really big, big, big even on the smallest
pocket receivers.
row°
THE CONAX
the world-accepted way to control high frequency
spillovers in FM due to preemphasis. Lets your
station maintain real high levels even with brass
and crashing cymbals and still avoid FCC citations.
THE REVERBERTRON
the new compact
reverberation system
which gives your sta-
tion that real big
.(
#
voice. With the Reverbertron you can
have that Carnegie
Hall effect as close as
the gain control on the Reverbertron. And there's
the added plus of an increase in apparent loudness of your station sound due to reverberation,
as originally described by Dr. Maxfield.
For complete details on psycho-acoustic sound
that sells write to Fairchild
the pacemaker in
-
professional audio products.
FAIRCHILD
RECORDING EQUIPMENT CORPORATION
10-40 45th Ave., Long Island City 1, N.Y.
happen. Naturally since the output has
been reduced, the control light becomes
dimmer and allows the signal to be
greater. However, the light has a slow
recovery time, 800 ms. Therefore, a general tapering off occurs. A switch can be
placed in the lamp circuit to disable the
lamp when it is desired to have the circuit function normally without compression.
The a.c. VTVM circuit is mainly conventional, however no provision for calibration is incorporated and a control is
placed in the input circuit so accuracy
is minimal. The VTVM is not used for
accurate measurements but rather as an
indicating device so that relative voltages in the lamp circuit may be observed. The VTVM is used in a manner
similar to a VU meter.
Installation of the Compressor
If the system in which the compressor
is to be incorporated has a program
amplifier and a preamp, the ideal method
of connecting would be to place the "signal" portion (photocell) between the
preamp and the program amplifier and
connecting the "control" portion (lamp)
to the output.
This circuit could also be placed at
low level inputs. However, care should
be taken with regard to shielding so that
hum and noise will not be at an objectionable level.
Before making connections to the amplifier, the following should be observed
First the amplifier should have no signal present; second connect the input
section first; third the control potentiometer should be adjusted to short circuit the lamp; then a signal should be
introduced into the amplifier to establish the proper operating level; then increase the signal slightly and adjust the
control potentiometer until the signal is
restored to the proper level by action of
the compressor. The grid control potentiometer and the lamp control potentiometer interact so repeated adjustments
will be necessary to establish the desired
operating parameters. It is most important that the indicating series light
be observed carefully during all adjustments so that the filament specifications
will not be exceeded.
Using a Raysistor, or equivalent device, for the heart of the system the
compressor can be made as elaborate
or simple as the constructor desires. The
Raysistor alone connected to the output
and input circuit gives you 60 db of
compression for less than fifteen dollars.
:
Æ
Circle 107 on Reader Service Card
AUDIO
Webcor Engineering
plus CGY styling!
Amplification and power supply all in one
handsome, portable carrying case
professionally oriented keyboard control and
tilt -out control panel
. sophisticated
computer -type reels and two graceful and
separate detachable "stereo -supreme"
speaker wings. Thank CGY for the most
elegant and professional looking tape recorder you'll ever tee-the Webcor Pro-
...
fessional.-
Incidentally, CGY is Chapman, Goldsmith
and Yamasaki- Internationally renowned
design firm. And Incidentally, you can thank
world famous Webcor engineers for the
finest sound studio you'll ever hear-with
speeds; 1/4 track stereo-record and playback; r/a track monaural -4 track record
and playback; simultaneous monaural record and playback; monaural echo effects;,
synchro-track and "sound with sound";
stereo and reverse stereo play; automatic
thread control and combination on/off/
ASO; push button reset digital counter;
automatic tape lifters and plenty more. See
the Professional soon, at your Webcor
dealer. You'll thank CGY and Webcor, too.
Under $500.00.
3
Widen your world with
WEBCOR
Webcor, Inc., 700 North Kingsbury/Chicago 60610
CIRCLE 147
DECEMBER, 1964
71
www.americanradiohistory.com
AmericanRadioHistory.Com
A
convenient service to AUDIO readers.
-
Order your books leisurely
save time and travel,
by mail
we pay the postage.
Designing and Building Hi-Fi Furniture
Jeff Markel
Written by a professional
hi-fi furniture designer
who has taught furniture
design at leading col-
Maintaining Hi-Fi Equipment
Joseph Marshall
A valuable reference for
anyone whose living or
hobby is servicing hi-fi
equipment. Outlines the
professional approach for
servicing all types of hifi components. Covers
trouble -shooting of elec-
leges, this book is an au-
acoustic problems. 224
pages.
No. 58 Paperback $2.90*
'1280 pages
3400 topics
1600
illustrations
Here is one single volume
with the most comprehensive coverage of every
phase of audio. Concise,
accurate explanations of
all audio and hi-fi subjects. More than 7 years
in preparation-the most
authoritative encyclopedic work with a unique
quick reference system for
instant answers to any
question. A vital complete reference book for
thentic reference of value
to the hi-fi fan and professional custom builder.
Covers everything from
types of woods to furniture finishing for the
mechanically adept; de
sign principles, styles and
tronic, mechanical and
"The AUDIO Cyclopedia"
Howard M. Tremaine
arrangements for the
decor minded. 224 pages.
No. 79 Paperback $2.90*
every audio engineer,
technician, and serious
audiophile.
No.123 $19.95*
The 6th AUDIO Anthology
The 5th AUDIO
McProud High Fidelity Omnibook
..---
Prepared and edited by
C. G. McProud, publisher
of Audio and noted authority and pioneer in
the field of high fidelity.
Contains
a
wealth of
ideas, how to's, what
to's, and when to's, written so plainly that both
engineer and layman can
appreciate its valuable
context. Covers planning,
problems with decoration,
cabinets and building hifi furniture. A perfect
guide.
No.115 $2.50*
G.
Edited by C.
Paper Cover $2.95*
MONTHLY SPECIAL! SAVE $5.00
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5th AUDIO ANTHOLOGY ($3.50)
By
the editors of AUDIO, the
original
magazine
about
fidelity. A 1962-1963
product review of stereo high
fidelity components. Valuable
reference for the high fidelity enthusiast and hobbyist.
Part I contains a thorough
discussion of the Problems of
a Stereo Installation; Part II
is a complete treatise on
Selecting o Tape Recorder.
Indispensable to the prospective buyer of stereo components and tape recorders.
Includes a section on where
to buy various stereo hi-fi
components and accessories.
156 pages.
high
AUDIO GUIDE
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techniques, sound effects,
editing and splicing, etc.
Invaluable to recording
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$3.95
No. 130
AUDIOGUIDE
-
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of high fidelity: FM STEREO
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A necessary
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$3.50
new compendium of
AUDIO knowledge. Here
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The
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AUDIO Clinic by Joseph
Giovanelli . . . noted
audio engineer and the
original high fidelity answer -man
EQUIPMENT
PROFILES edited by C. G.
McProud . . . Editor of
AUDIO. Here is a wealth
of hi-fi and audio information. Answers to the
most important issues in
high fidelity and a valuable reference.
No. 124 Volume I $2.00'
G.
publisher of AUDIO. Includes
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McProud,
A
corders. Covers room
acoustics, microphone
No. 112
by C.
publisher of AUDIO. An anthology of the most signifioilcant articles covering: stereo
recording and reproduction;
stereo multiplex; measurements; stereo technology,
construction and theory
which appeared in AUDIO
during 1958 and 1959. The
5th is truly a collectors' item
and a valuable reference for
the professional engineer,
teacher, student, hobbyist and
hi-fi fan. 144 pages.
"the best of AUDIO"edited by C. G. McProud
A complete book on home
recording by the author
of High Fidelity Simplified. Easy to read and
learn the techniques required for professional
results with home re-
;APE RECORDING
Edited
No. 125
Tape Recorders and Tape Recording'
Harold D. Weiler
;APE REGt?RiIERS,
Anthology
season
Mnii
-+
tww.:
$1.00
No. 127
High Fidelity Simplified
Harold
D.
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TOTAL VALUE ALL FOUR BOOKS . . . $10.95
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This offer expires December
3 1,
1964, and
is
good only on direct order to the Publisher.
CIRCLE 05400
AUDIO Bookshelf-RADIO
P.
MAGAZINES, INC.
O. Box 629, Mineola, New York 11502
Please send me the books
full remittance of $
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125
I
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79
127
I
-
complete hi-fi story
answers oll questions also,'
tuners, changers, amplifiers:
tape recorders, speakers.
record players, etc. Lots of
ideas for custom installaThe
tions. Tells how to achieve
concert hall reception in
your home. 216 pages.
No. 142
*AII U.S.A. and Canadian
orders shipped postpaid.
Getting The Most Out Of Your Tape Recorder
Herman Burstein
Written in "plain talk" for
the man who has, or wishes
am enclosing the
(No C.O.D. or billing.)
115
123
112
251
142
130
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124
OS400
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ADDRESS
STATE
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AUDIO
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answers the myriad questions raised by tope recording enthusiasts. Its chapters
cover every phase of operation and maintenonce-from
adding a tope recorder to
the hi-fi system, to a thorough dissertation on microphones. Lots of practical
information on how to buy.
176 pages.
NAME
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bookshelves of thousands of AUDIO
regulars men and women in
all fields of American enterprise.
The six, a library of 250 meaningful articles, are a documentation
of the progress and development
of the audio art -the science of
recording and reproducing music
and sound.
-
-
And now, with the Seventh
AUDIO Anthology, we add to this
valuable reference work. The
important articles contained
in this volume appeared in
AUDIO in the past two years
1962 and 1963.
-
=v.p
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copies of the 7th AUDIO
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JAll
(from page 8)
How Much Does
High Fidelity Weigh?
corded several times, and it was desirable
to use the best portions of each take to
avoid as much of the inner groove distortion and the various noises that were
on the originals. First a court stenographer was called in to make a complete
transcript of all of the words in the
songs. This transcript ran to about 150
pages. Next, Jac Holzman, head of
Elektra, carefully marked the transcribed
text, using a special code he has devised,
to note each inflection used by Woody.
And from this marked text, an editing
diagram was prepared, indicating where
each cut would be made. An editor spent
five days making a rough cut from this
diagram.
In three days of recording, it was to
be expected that much of the same ma-
terial was covered several times over.
Finally, the splices were all fine cut, and
pauses were eliminated. Removing clicks
and pops was the next operation; over
1,000 such sounds were cut out of the
NEW AKG K-50 HI-FI HEADPHONE SET
Imported from Austria, home town of music
...only 3.8 ounces!
Yes, that's all the weight you carry
when you listen to stereo or mono
music with the New AKG K-50
Lightest by
HEADPHONE SET
...
far and Highest in Fidelity. Rated
best by the experts in recent surveys.
And there's considerably more to
the K-50 than pure comfort; there
are smooth frequency response from
20-20,000 CPS, exceptionally low distortion and high acoustic efficiency.
Slim and trim, you can wear it for
hours without feeling as though your
head were in a clamp! You can listen
to its clean, bright treble and full,
round bass in complete privacy and
comfort. M'lady enjoys it, too. So
compact and light, K-50 can't spoil
$22.50
her hair-do!
Ask your hi-fi dealer for a demonstration today. Write now for free descriptive literature. Dept. 412
aai
National Sales and Service:
AUDIO APPLICATIONS, INC.
19 Grand Ave., Englewood, N. J. 07631
master tape.
Before the master was ready for cutting; however, it was necessary to prepare a cutting cue sheet so that portions
of songs taken from different discs could
be balanced and filtered to smooth out
differences between sections with swishes,
hisses, rumble and fry and those sections
that were clear. Armed with his cue
sheet, Holzman went to Mastertone Studios, where he and engineer Sid Feldman
spent an entire day cutting the set.
Holzman propped his 2-in. thick cutting
script on a music stand and cued Feldman on levels while making balance adjustments at a bank of Pultec equalizers. For about ten hours, two pairs of
hands turned knobs and flipped switches
with split second precision.
The next step was to get a set of the
discs to Guthrie, who has been hospital -
RECORDING ENGINEER,
VENEZUELA
Experienced engineer to take charge of
recording studio and stamping plant in
Venezuela. 5 years experience minimum.
State salary. Write J. )3rillenbourg, P. 0.
Box 10716, Sabana. Grande, Caracas, Venezuela.
PRODUCT DEVELOPMENT
SPECIALIST
Vigorous expansion has created fine opportunity for mid -management position as a
product development specialist. Responsibility includes liaison between sales and
engineering; creative copy assistance to
advertising and agency; new idea study;
product sales direction. Man chosen will report directly to Marketing VP salary commensurate with experience. Please write
with assurance of absolute confidential
treatment. L. LeKashman, Electro -Voice,
Inc. Buchanan, Michigan.
CLASSIFIED
Rates: 10e per word per Insertion for noncommercial
advertisements: 250 per word for commercial advertisements. Rates are net, and no discounts will be
allowed. Copy must be accompanied by remittance In
full, and must reach the New York office by the
Rust of the month preceding the date of Issue.
HIGH FIDELITY SPEAKERS REPAIRED
AMPRITE SPEAKER SERVICE
168 W. 23rd St., New York 11, N. Y.
CH 3-4812
HARPSICHORD. Same as owned by Philadelphia Orchestra and RCA Victor. In kit
form for home workshop assembly, $150.
Clavichord kit, $100. Free brochure. Write :
Zuckermann Harpsichords, Dept. R, 115 Christopher St., New York 14, N. Y.
LEARN WHILE ASLEEP. Hypnotize with
recorder, phonograph Details, strange catalog
free. Sleep-Learning, Box 24 -AE, Olympia,
Washington.
FREE! Send for money -saving stereo catalog Al2M and lowest quotations on your individual components, tape recorder, or system
requirements. Electronic Values, Inc. 200 West
20th St., New York, N. Y. 10011.
!
HI-FI COMPONENTS, tape recorders at
guaranteed "We Will Not Be Undersold"
prices. 15 -day money -back guarantee, 2 -year
warranty. NO CATALOG. QUOTATIONS
FREE. HI -FIDELITY CENTER, 1797-V 1st
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COLLECTOR WANTS World, Associated,
Muzak, etc. transcriptions, from 1930-1940
period. Also want transcription catalogs, card
files, promo material. R. V. Nicholas, 4200
Blackthorne, Long Beach 8, California.
try VITA
SOMETHING SLIPPING? .
DRIVE, an excellent rubber drive cleaner that
definitely prevents slippage of pinch wheels,
intermediate drives and belts used in tape
recorders, record players and record changers.
Used by service organizations throughout the
world. $1.25 one ounce bottle (U.S.A.) A
product of FRIEND'S Mfg., Co., 614 Arch
Street, Philadelphia, Pa. 19106.
FREE! Tape recording handbook. Sarkes
Tarzian's Galaxie tape. Pofe, 1716-A Northfield, Muncie, Indiana.
Bruel & Kjaer (B&K) Laboratory audio test
equipment at less than % original cost Type
2110 A -F spectometer, $975; Type 2603B
voltmeter -amplifier, $395 ; Type 1014 A -F
oscillator, $595 ; Type 2305A level recorder,
$950. Used, but in excellent condition. Electronicraft, Box 13, Binghamton, N. Y. 13902.
Phone : 607-724-5785.
CONCERTONE TAPE RECORDERS Model
20, $200, Model 62 (needs work) $200, 71/_-15
ips, H -P 300A distortion analyzer, $200, Dumont 241 oscilloscope, $50, FOB add $15 packing. Want Presto 6N microgroove feedscrews.
accessories; R. E. Lockard. Jr., 1709 W. 127
St., Los Angeles, Calif. 90047.
WANTED: Ampex tape recorder, PR10-2,
602-2, 601-2, etc. Ampex mixer MX35, stereo
or mono something equal in quality. Professional microphones, McIntosh MR71 tuner.
Any kind professional equipment. Must be in
excellent condition. Johnny Price, 11819 Lippitt, Dallas, Texas 75218.
Used Mylar tape, 1800 feet, 1 mil. $1 each.
Send check with order. B. Freeman, 800 W. 87
St., Kansas City, Missouri 64114.
.
!
:
Audio plans for constructing tape degausser,
crossover network, speaker relay. $1. Jef Enterprises, P. O. Box 968-C, Los Altos, California.
WANTED: Old locks, keys, handcuffs,
strongboxes, coins, rifles, gun catalogs, gun
books and oil lamps. Before 1900. Send description, condition, price, manufacturers in
first letter. V. Reyna, P. O. Box 568, San
Francisco 1, Calif.
FOR SALE: JansZen Z200W speaker system. Any reasonable offer, or will buy yours
to match. Carl Giffels, 3 Rockwood, Florham
Park, N. J.
FOR SALE : AUDIO May, 1955-June, 1959
complete. 15 miscellaneous issues 1951-1953.
Also Electronics Magazine, 1944-1962. Make
offer. Frank Jackson, 747 Britton Road, Rochester, New York.
AUDIO
74
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AmericanRadioHistory.Com
.
DECEMBER, 1964
HOW
for a long time. He had been told
of the plan to release these recordings,
and he had insisted that he be the first
to hear the final pressings. According to
Lou Gordon, Harold Leventhal and Pete
Seeger, who are the trustees of the Guthrie Children's Trust Fund, to which all
royalties from this recording will be
paid, Woody was deeply moved at hearing them.
What emerges from these three hours
of long playing interview and song is
more than a portrait of a fine folk
singer, song writer and itinerant social
critic. This recording is a powerful documentation of the depression years in
the Oklahoma and Texas Dust Bowl.
Through these conversations and songs,
a slice of American history that had become a pale memory to most of us
emerges with fresh immediacy. The
southwestern United States in the thirties is graphically delineated; such matters as poverty, bank foreclosures, the
Colored "situation," migration to California, chain gangs and hoboing are deized
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75
DECEMBER, 1964
www.americanradiohistory.com
AmericanRadioHistory.Com
SUBJECT INDLX
1964
ACOUSTICS
"Purist" Tackles Room Acoustics; J.
Electro -Voice Speaker System Model Six;
April p. 42.
Empire Stereo Pickup Model 880-P;
AMPLIFIERS
A Direct Approach to Q -Point Stabilization; Frank W. Brands. April p. 44.
A Houseful of Hi Fi; Herbert M. Honig.
Fisher 3 -Way Speaker System Model
XP -10; March p. 54.
Furn-a-Kit Equipment Cabinet Kit 2600
A
W. Linsley. April p. 19.
March p. 42.
A New Triode Amplifier; Robert M. Voss
and Robert Ellis. July p. 22.
All Silicon Tape Playback Preamps and
Recording Circuit; John Abajian and
Dwight V. Jones. Oct. p. 22.
Class -D for Efficiency; Peter A. Stark.
Part I, June p. 23; Part II, July p. 24;
Part III, Aug. p. 23.
Intermodulation Distortion-Pros, Cons,
and Hows; Mannie Horowitz, Jan. p. 38.
Low -Cost High -Performance
Volume
Compressor; S. S. Andrews, Dec. p. 19.
Power; Mannie Horowitz, March p. 25.
The El Cheapo 2-30; R. R. Moore, Nov.
p. 19.
CROSSOVERS
Transient Performance of Loudspeaker
Dividing Networks; Robert M. Mitchell.
Jan. p. 24.
CURVE PLOTTING
A Note on Curve Plotting; Virginia Rettinger. Sept. p. 24.
DISTORTION
Bad Sound From Great Composers;
Lewis A. Harlow. Feb. p. 21.
Intermodulation Distortion -Pros, Cons,
and Hows; Mannie Horowitz. Jan. p.
38.
Reducing Distortion in Stereo Phonograph Systems; J. G. Woodward, Part
I, Feb. p. 23; Part II, March p. 28.
Transient Generators for Audio Testing;
John L. Grauer, Sept. p. 22.
EQUIPMENT PROFILES
Acoustic Research
ADC Loudspeaker, Brentwood 303A; Nov.
p. 68.
ADC Stereo Pickup, Point Four; March
p. 52.
Altec Lansing Stereo Amplifier Model
360A; April p. 40.
Ampex Stereo Tape Recorder Model 2070;
Sept. p. 46.
Barker & Williamson Audio Oscillator
Model 210; July p. 32.
Barker & Williamson Distortion and A.C.
Volt Meter Model 410; Sept. p. 46.
Bell Solid -State Receiver Imperial 1000;
May p. 46.
Bogen
Cipher Denon 8000 Tape Recorder; Jan.
p. 46.
Clark Stereo Headphones Model 100;
Feb. p. 40.
Concord Tape Recorder Model 884; March
p. 50.
Dynaco-B
& O Stereo Ribbon Microphone Model 200; June p. 37.
Dynaco Stereo Control Amplifier SCA-35;
March p. 52.
EICO IM -Harmonic Distortion Meter
Model 902W; Feb. p. 40.
Electro -Voice Microphone Model 644; Oct.
p. 112.
April p. 63.
Series; March p. 56.
Goodmans Loudspeaker System Maximus 1; Nov. p. 66.
Harman-Kardon 1000 Series Tuner and
Amplifier F1000T, A1000T; June p. 37.
Harman-Kardon Transistorized Stereo
Receiver Model SR -900; Oct. p. 88.
Heathkit Regulated Power Supply Model
IP -20; Sept. p. 48.
James B. Lansing "Olympus" Speaker
System Model C-50; June p. 37.
Magnecord Stereo Tape Recorder Model
1024 -HF; Nov. p. 66.
McIntosh FM -Stereo Tuner Model MR67;
Feb. p. 38.
OKI Stereo Tape Recorder Model 555;
Oct. p. 90.
PML Condenser Microphone Model EC -61:
March p. 56.
RCA Ribbon Microphone Model SK -46;
July p. 34.
H. H. Scott FM -Stereo Tuner -Amplifier
Model 340-B; Jan. p. 45.
H. H. Scott Solid -State FM -Stereo Tuner
Model 312; July p. 32.
Shure Stereo Cartridge V-15, May p. 48.
Stanton Stereotable System, Model 800B
Jan. p. 44.
Thorens Automatic Turntable TD -224;
May p. 48.
Uher Portable Recorder Model 4000
Report-S; April p. 38.
Weathers
FANTASY
Basic Questions and Answers; Christopher Faye. Feb. p. 36.
Hi Fi and the British; Alan Watling.
June p. 53.
Hi Fi and the British: Privacy; Alan
Watling. Sept. p. 38.
FM
A Solid -State
Ultra -Linear Wideband
FM Demodulator; Ralph Glasgal. May
p. 25.
A Transistor FM Squelch; K. E. Springer.
March p. 21.
Tuner Alignment for Quality FM Reception; Arthur L. Boynton. July p. 19.
GENERAL
Bad Sound From Great Composers; Lewis
A. Harlow. Feb. p. 21.
IITRI; R & D for the Tape Industry;
Robert Angus. Sept. p. 26.
LAW
Freedom of Speech, Sound Trucks and the
Constitution; Albert Woodruff Gray.
April p. 32.
Tape Recorders and the Copyright Law;
Eric Darmstaedter. May p. 50.
LOUDSPEAKERS
An Engineer Looks at Exponential
Horns; W. A. Dodge. Nov. p. 30.
Automatic Speaker Connector; Ronald L.
Ives. Sept. p. 19.
Central -versus -Distributed Loudspeaker
Systems; David L. Klepper, June p. 19.
Techniques of Making Live -versus -Recorded Comparisons; Edgar Villchur.
Oct. p. 34.
Telstar -Shaped Electrostatic Speakers;
R. J. Matthys. Part I, May p. 19; Part
II, June p. 23.
Ton -and -a -Quarter of Sound; Walter
Wysoczanski. Jan. p. 19.
Transient Performance of Loudspeaker
Dividing Networks; Robert M. Mitchell.
Jan. p. 24.
MICROPHONES
A Ribbon Microphone for Stereo; E. R.
Madsen. April p. 26.
MUSICAL INSTRUMENTS
An All -Electronic Method for Tuning Organs and Pianos; A. M. Seybold. Part
III, March p. 22. (Parts I and II appeared in 1963.)
An Electronic Organ Design; Winthrop
S. Pike. Part I, Oct. p. 19; Part II,
Nov. p. 24.
Electronic Organ Tone Coloring, D. Wolkov Dec. p. 25.
RECORDING
A Note on Curve Plotting; Virginia Rettinger. Sept. p. 24.
A Re -Recording Filter; H. E. Riekels,
Jr. Feb. p. 35.
All Silicon Tape Playback Preamps and
Recording Circuit: John Abajian and
Dwight V. Jones. Oct. p. 22.
Low-Cost High -Performance Volume
Compressor; S. S. Andrews, Dec. p. 19.
Master Timer; William G. Dilley. Feb. p.
19.
Recording a Community Music Festival;
Gil Daney. March p. 19.
Recording the Muse on Tape; Arthur C.
Matthews, Dec. p. 21.
Reducing Distortion in Stereo Phonograph
Systems; J. G. Woodward. Part I, Feb.
p. 23; Part II, March p. 28.
Stereo Disc Recording Comes of Age;
Duane H. Cooper. Jan. p. 30.
Techniques of making Live -versus- Recorded Comparisons; Edgar Villchur.
Oct. p. 34.
The Elliptical Stylus; J. Kogen and R.
Samson. May p. 33.
Tape Recorders and the Copyright Law;
Eric Darmstaedter. May p. 50.
The RCA Victor "Dynagroove" System;
Harry F. Olson. Part I, Nov. p. 22; Part
II, Dec. p.
44.
RELAYS
Automatic Speaker Connector; Ronald L.
Ives. Sept. p. 19.
Very Low Voltage Relay Operation. Ronald L. Ives. Jan. p. 36.
REMOTE CONTROL
Automatic Speaker Connector; Ronald L.
Ives. Sept. p. 19.
Controlling Sound -Reinforcement Systems
Automatically; David Klepper. April p.
22.
Very Low Voltage Relay Operation. Ronald L. Ives. Jan. p. 36.
AUDIO
76
www.americanradiohistory.com
AmericanRadioHistory.Com
DECEMBER, 1964
SOUND REINFORCEMENT
A Basic Course in Commercial Sound;
Norman Crowhurst. Chap. I, April p.
33; Chap. II, May p. 41; Chap. III, June
p. 33; Chap. IV, July p. 28; Chap. V,
Aug. p. 19; Chap. VI, Sept. p. 35; Chap.
VII, Oct. p. 75; Chap. VIII, Nov. p. 43;
Chap. IX, Dec. p. 38.
Central -versus -Distributed Loudspeaker
Systems; David L. Klepper. June p. 19.
Controlling Sound -Reinforcement Systems Automatically; David Klepper.
TEST EQUIPMENT
Intermodulation Distortion-Pros, Cons,
and Hows; Mannie Horowitz. Jan. p. 38.
Power; Mannie Horowitz. March p. 25.
Transient Generators for Audio Testing;
John L. Grauer. Sept. p. 22.
.
April p. 22.
TRANSISTORS
A Direct Approach to Q -Point Stabiliza
tion; Frank W. Brands. April p. 44.
A Solid -State Ultra -Linear Wideband FM
Demodulator; Ralph Glasgal. May p. 25.
A Transistor FM Squelch; K. E. Springer.
March p. 21.
All Silicon Tape Playback Preamps and
Recording Circuit; John Abajian and
Dwight V. Jones. Oct. p. 22.
Class -D for Efficiency; Peter A. Stark.
Part I, June p. 23; Part II, July p. 24;
Part III, Aug. p. 23.
The El Cheapo 2-30; R. R. Moore. Nov. p.
19.
AUTHOR INllEX
1964
Abajian, John and Dwight V. Jones. All
Silicon Tape Playback Preamps and Recording Circuit. Oct. p. 22.
Andrews, S. S. Low -Cost High -Performance Volume Compressor. Dec. p. 19.
Angus, Robert.
IITRI: R & D for the Tape Industry.
Sept. p. 26.
Boynton, Arthur L.
Tuner Alignment for Quality FM Reception. July p. 19.
Brands, Frank W.
A Direct Approach to Q -Point Stabilization. April p. 44.
Cooper, Duane H.
Stereo Disc Recording Comes of Age.
Jan. p.
30.
Crowhurst, Norman.
A Basic Course in Commercial Sound.
Chap. I, April p. 33. Chap. II, May p. 41.
Chap. III, June p. 33. Chap. IV, July p.
28. Chap. V, Aug. p. 19. Chap. VI, Sept.
p. 35. Chap. VII, Oct. p. 76. Chap. VIII,
Nov. p. 43, Chap. IX, Dec. p. 38.
Daney, Gil.
Recording a Community Music Festival.
March p. 19.
Darmstaedter, Eric.
Tape Recorders and the Copyright Law.
May p. 50.
Dilley, William G.
Master Timer. Feb. p. 19.
Dodge, W. A.
An Engineer Looks at Exponential
Horns. Nov. p. 30.
Faye, Christopher.
Basic Questions and Answers. Feb. p.
36.
Glasgal, Ralph.
A Solid -State Ultra -Linear Wideband
FM Demodulator. May p. 25.
Grauer, John L.
Transient Generators for Audio Testing.
Sept. p. 22.
AUDIO
Gray, Albert Woodruff.
Freedom of Speech, Sound Trucks and
the Constitution. April p. 32.
Harlow, Lewis A.
Bad Sound From Great Composers. Feb.
p. 21.
Honig, Herbert M.
A Houseful of Hi Fi. March p. 42.
Horowitz, Mannie.
Intermodulation Distortion-Pros, Cons,
and Hows. Jan. p. 38.
Horowitz, Mannie.
Power. March p. 25.
Ives, Ronald L.
Automatic Speaker Connector. Sept. p.
19.
Very Low Voltage Relay Operation.
Jan. p. 36.
Jones, Dwight V. and John Abajian.
All Silicon Tape Playback Preamps and
Recording Circuit. Oct p. 22.
Klepper, David L.
Central-versus -Distributed Loudspeaker
Systems. June p. 19.
Controlling Sound -Reinforcement Systems Automatically. April p. 22.
Kogen, J. and R. Samson
The Elliptical Stylus. May p. 33.
Linsley, J. W.
A "Purist" Tackles Room Acoustics.
April p. 19.
Madsen, E. R.
A Ribbon Microphone for Stereo. April
p. 26.
Matthews, Arthur C. Recording the Muse
on Tape. Dec. p. 21.
Matthys, R. J.
Telstar -Shaped Electrostatic Speakers
Part I, May p. 19; Part II, June p. 23.
Mitchell, Robert M.
Transient Performance of Loudspeaker
Dividing Networks. Jan. p. 24.
Moore, R. R.
The El Cheapo 2-30. Nov. p. 19.
Olson, Harry F.
The RCA Victor "Dynogroove" System.
Part I, Nov. p. 22, Part II, Dec. p. 44.
Pike, Winthrop S.
An Electronic Organ Design. Part I,
Oct. p. 19; Part II, Nov. p. 24.
Riekels, H. E., Jr.
A Re -Recording Filter. Feb. p. 35.
Rettinger, Virginia.
A Note on Curve Plotting. Sept. p. 24.
Samson, R. and J. Kogen.
The Elliptical Stylus. May p. 33.
Seybold, A. M.
An All -Electronic Method for Tuning
Organs and Pianos. Part III. March
p. 22.
Springer, K. E.
A Transistor FM Squelch. March p. 21.
Stark, Peter A.
Class -D for Efficiency. Part I, June p.
23. Part II, July p. 24; Part III, Aug. p.
23.
Villchur, Edgar.
Techniques of Making Live -versusRecorded Comparisons. Oct. p. 34.
Voss, Robert M. and Robert Ellis.
A New Triode Amplifier. July p. 22.
Watling, Alan.
Hi Fi and the British. June p. 53.
Hi Fi and the British: Privacy Sept. p.
38.
Wolkov, D. Electronic Organ Tone Coloring. Dec. p. 25.
Woodward, J. G.
Reducing Distortion in Stereo Phonograph Systems. Part I, Feb. p. 23, Part
II, March p. 28.
Wysoczanski, Walter.
Ton -and -a -Quarter of Sound. Jan. p. 19.
77
DECEMBER, 1964
www.americanradiohistory.com
AmericanRadioHistory.Com
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ADVERTISING
INDEX
High Fidelity Magazine
on New Acoustech
Solid State Kit:
"... MAGNIFICENT
PERFORMANCE
..."
Ow
Acoustech, Inc.
78
11
Acoustic Research, Inc.
4
Acoustical Manufacturing Co., Ltd.
AKG of America
62
Altec Lansing Corporation
29-31, 63
Amplifier Corp. of America
75
Audio Applications, Inc.
74
72
Audio Bookshelf
Audio Exchange
68
Benjamin Electronic Sound Corp.
Bogen Communications Div.,
Lear Siegler, Inc.
Bozak
British Industries Corp.
..
Coy.
III
40,
41
5
3
Chancellor Electronics, Inc.
Classified
Concertone
61
Dynaco, Inc.
15
74
9
36, 37
69
Electro -Voice, Inc.
Cov. IV,
75
Electro -Voice Sound Systems
Elpa Marketing Industries
56, 57
43
EMI Scope Electronics Corporation
33, 34
Empire Scientific
Eastman Kodak
EICO Electronic Instr. Co.
1
"...`state
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one of the truly
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Here are further comments from the November, 1964 report on the new Acoustech IV
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.
harmonic distortion was literally too low
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IM at the 2-volt level was
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These figures are among
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Frequency response
was literally a flat line over the audible range
. the
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superior, professional grade construction
.
listening quality
'wide open,' clean, utterly transparent and noise free. The Acoustech
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FAIRCHILD
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10-40 45th Avenue, Long Island City
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Fairchild Recording Equipment
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Fisher Radio Corp.
71, 75, 78
75
Garrard Sales Corp.
3
7
Harvard Electronics Co.
Hi Fidelity Center
75
JFD Electronics Corp.
67
KLH Research & Development Corp.
8
....
60
Koss Rek-O-Kut
KSC Systems, Inc.
47
70
Lafayette Radio
59
49
55
Lansing, James B., Sound, Inc.
LTV University
New MAESTRO, an all -horn -loaded,
compression
system, the
Marantz, Inc.
Martel Electronics
McIntosh Laboratory, Inc.
45
66
Network Research & Manufacturing Corp.
North American Philips Co.
6
12
Pickering & Company, Inc.
17
53
-
operated
world's
installation -, gives
me
uni
-
bass
first for hocrisp, clean
and clear bass unobtainable by any
cone -type woofer.
Other models: Orchestra, Concert,
Symphonia and Symphonietta.
ACOUSTECH
ACOUSTECH, INC.
Dept. A-12, 139 Main Street,
Cambridge, Mass. 02142
RCA, Electronic Components and Devices 13
Sarkes Tarzian, Inc.
Scott, H. H., Inc.
FREE
Please send free booklet "Why Solid State Amplifiers Can Sound Better" and full information on
58
Cov. II
Sherwood Electronics Laboratories, Inc. .. 18
26, 27, 54, 75
Shure Brothers, Inc.
70
Syncron Corporation
For
further details, contact:
Provo High Fidelity
P.O.Box 204, Batavia,
N.Y. 14021
Acoustech solid state kits to
Viking of Minneapolis, Inc.
64, 65
Name
I
Webcor, Inc.
Address
;City
7one
State
71
YL ACOUSTIC CO, LTD.
YL Acoustic
Co., Ltd.
78
19. Shiba.Tamura.cho, Minato-ku, Tokyo, JAPAN
Circle 155 on Reader Service Card
Circle 153 on Reader Service Card
AUDIO
78
www.americanradiohistory.com
AmericanRadioHistory.Com
DECEMBER, 1964
Get in the groove -any groove...
gently!
New Miracord 18H
single record play turntable operates manually or automatically. Offers new
cueing record band selector. Gently lowers arm and sets stylus in desired band or groove. Includes
famous Miracord features: automatic pushbutton controls, Papst hysteresis-synchronous motor, heavy
balanced turntable platter, transcription arm, four speeds.
Your hi-fi dealer will soon be showing the new Miracord 18H alongside the now famous Models 10 and
10H. Be sure to see it. Price is $119.50 (less cartridge and base). For further details, write direct:
BENJAMIN'
Benjamin Electronic Sound Corp. 80 Swalm St., Westbury, N.Y. Sole U.S. distributor
INIRACOR®
Miracord turntables, Elac cartridges and other Electroacustic® audio components.
Circle 101 on treader Service Card
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