Feb
m
i
wi
... the authoritative magazine
about high fidelity
FEBRUARY 1967
Announcing an important Scott innovation
in high
fidelity...
Scott Integrated Circuits...now in 3 Scott receivers
Hear stations you've never been able to hear before... brought to life with amazing clarity!
Integrated Circuits...
the computer -born miracle.
Originally developed as a space saving device in giant computers, the
integrated circuit ("IC") is a complete
circuit in miniature
often barely
larger than a grain, of sand. The various elements of
the circuit ...transistors, resistors, and wiring ...are
permanently carved into a microscopic layer of silicon. There are no lose wires or parts that can change,
age, fall out, or wear out. In fact, Scott Integrated
Circuits can last literally thousands of years.
...
More performance in less space.
Used in the vital FM tuner IF strip, Scott Integrated
Circuits actually incorporate more circuitry in less
space. The new Scott IF strip now contains 20 transistors, as compared to four in the previous model.
Scott's previous IF strip, without IC's, gave superb
old IF strip
capture ratio and selectivity figures of 2.5 dB and 45
dB, respectively. Scott's new Integrated Circuit IF strip
is conservatively rated at 1.8 dB capture ratio and
46 dB selectivity. Independent test reports, however,
show the new Scott Integrated Circuits to be consistently capable of an incredible 0.8 dB capture ratio!
What Scott IC's mean to you.
Now you can hear more stations with less noise
and interference. Weak, distant stations that you
never have been able to receive before will suddenly
appear with amazing clarity. Outside interference
from electric razors, auto ignitions, etc., will be drastically reduced. And, you can count on enjoying this
amazing performance for many, many years ...thanks
to the absolute reliability of Scott Integrated Circuits.
When will Scott
be available ?
IC
components
Scott Integrated Circuit receivers are at your Scott
dealer's showroom right now. Scott Integrated Circuits
are incorporated into the design of the 388 120 -Watt
AM/ FM stereo receiver, the 348 120 -Watt FM stereo
receiver, and the 344B 85-Watt FM stereo receiver.
Your Scott dealer will be glad to demonstrate to you
the amazing capabilities of these new receivers.
Scott
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0 SCOTT®
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H. H. Scott, Inc., Dept.
IC
IF strip
-filled, fully illustrated booklet on Scott IntegraFREE Fact
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Another innovation from Scott, manufacturers of superb components, compacts, kits, speakers, and consoles.
Vol. 51, No. 2
February, 1967
AUDIO
RAMO
Successor to
,
41 in a series of discussions
by Electro -Voice engineers
Number
Est. 1911
SANFORD L. CAHN
Marketing Director
GEORGE PORTER
Art Director
C. G. MC PROUD
Editor and Publisher
PETER RENICH
Asst. Art Director
LARRY ZIDE
Contributing Editors
Managing Editor
JOSEPH GIOVANELLI
HAROLD D. WEILER
HAROLD LAWRENCE
R. KENNETH BAXTER
CHESTER SANTON
HERMAN BURSTEIN
BERTRAM STANLEIGH
Production Manager
HENRY A. SCHOBER
Business Manager
Video Editor
EDWARD TATNALL CANBY
Music Editor
AUDIO
LEE IRGANG
Circulation Manager
Articles
Professional Tone Controls 27
Audio Measurements Course-Part 13 36
Jazz in Greenwich Village (Cover Story) 42
Arthur C. Davis and
Don Davis
Norman H. Crowhurst
Larry Zide
AUDIO Reviews
The AUDIO Music and Record Review
Section
Classical
Light Listening
Jazz and All That
About Music
AUDIO
44
44
50
53
54
Edward Tatnall Canby
Chester Santon
Bertram Stanleigh
Harold Lawrence
Profiles
Knight -Kit Integrated Amplifier and
Stereo Tuner 56
Shure Stereo Cartridge 58
IMC Boxer Fan 53
Models KG 895 and
KG 790
V-15 11
AUDIO in General
Audioclinic
Letters
Fundamental AUDIO
Audio ETC
Editor's Review
Sound & Sight
Tape Guide
New Products
Industry Notes
Advertising Index
t
ABC =
eYa4
2
Joseph Giovanelli
10
12
13
24
32
60
64
65
Martin Leynard
Edward Tatnall Canby
Harold D. Weiler
Herman Burstein
66
AUDIO (title registered U. S. Pat. Off.) is published monthly by North
American Publishing Co., I. J. Borowsky, President: Frank Nemeyer,
G McProud, and Arthur Situer, Vice Presidents. Executive and
Editorial Offices, 134 North 13th St., Philadelphia, Pa. 19107. Subscription rates-U.S. Possesions, Canada, and Mexico, $5.00 for one year
$9.00 for two years all other countries, $6.00 per year. Printed in
U.S.A. at Philadelphia, Pa. All rights reserved. Entire contents copyrighted 1967 by North American Publishing Co. Second class postage
paid at Philadelphia, Pa., and additional mailing offices.
REGIDNAL SALES OFFICES: Sanford L. Cahn, Art Sitner, Robert
Cooper 663 Fifth Ave., New York, N. Y. 10022 (212) 753-8824.
Richa.rd Reed, 205 W. Wacker Drive, Chicago, Ill. 60606; (312) 332-3910.
Leonard Gold, 1900 Euclid Ave., Cleveland, Ohio 44125 (216) 621-4992.
Jay ,tartin, 9350 Wilshire Blvd., Beverly Hills, Calif. (213) 273-1495.
REPRESENTATIVE: Warren Birkenhead, Inc., No. 25, 2-chome, Shiba
Hamamatsu -cho, Minato-ku, Tokyo, Japan.
C.
;
;
AUDIO,
Editorial and Publishing Offices, 134 N. 13th St., Phila., Pa. 19107
Postmaster: Send Form 3579 to the above address.
Must every acoustic suspension speaker
system be one specific size for optimum
performance? Or, put another way, is there
anything about the acoustic suspension
principle that dictates the small bookshelf
form that most of these speakers assume?
And are other sizes necessarily inferior?
A quick review of some of the factors that
determine enclosure size for acoustic suspension systems might well be in order.
Over most of the sound spectrum, cone
motion is controlled by moving mass, and
stiffness of either the cone suspension or
the enclosure has no effect. Near resonance
however, motion is controlled by the combination of mass, stiffness of cone suspension and air, and total resistance of the
cone suspension, enclosure padding, and
electrodynamic damping (which rises as
speaker efficiency is increased).
The heart of the acoustic suspension principle is the substitution of acoustic stiffness of the air in a sealed enclosure for
suspension stiffness. Of course enough
speaker suspension stiffness must be retained to maintain voice coil centering and
prevent coil "bottoming." But air stiffness
must be greater than suspension stiffness
by a factor of ten or more to effectively
control cone motion.
Two primary advantages can be ascribed
to the acoustic suspension idea. First, enclosure size can be sharply reduced from
the "infinite" enclosure usually recommended for a speaker of similar size with
conventional suspension. Second, the air
spring can be more linear than many mechanical suspensions.
Successful acoustic suspension systems
have been constructed that are vastly different in size than the "bookshelf" norm.
An unusual example is the current E -V
Patrician 800 with a 30 -inch woofer. Another "large" acoustic suspension system
is the E -V SIX with its 18 -inch woofer.
Significant size reduction has been accomplished with both systems without compromising performance.
One frequently overlooked factor in determining enclosure size for acoustic suspension systems is the efficiency of the
speaker. High efficiency speakers require
larger air volume to avoid over-damping
with consequent reduction in bass, since
high electromagnetic damping is a product
of high efficiency. Acoustic suspension
systems must, therefore, vary widely in
size to provide optimum response from
the loudspeaker.
For technical data on any E-V product, write:
ELECTRO -VOICE, INC., Dept. 273A
602 Cecil St., Buchanan, Michigan 49107
£'kat3vc°
SETTING NEW STANDARDS IN SOUND
Check No. 60 on Reader Service Card.
1
www.americanradiohistory.com
AUDIO CLINIC
Coming
Joseph Giovanelli
Articles
"Tracking Capability of Phono
Pickups," J. G. Woodward. Just
what is involved in tracking a
disc?
-
Mountain
"Skating Force
or Molehill," R. S. Oakley. The
author describes the pros and
cons of skating force compensation.
"Get to Know the Deciberin which George H. R.
O'Donnell simplifies the calculations involving the ubiquitous
Better"
dB.
Profiles
Wharfedale W-20 Speakers
Dyna PAS -3
preamplifier and
Stereo 120 amplifier
Pioneer Turntable System
On the Newstands, at your
favorite audio dealer's or in
your own mailbox.
About the Cover
The intimate relationship between the worlds of music and
recording are exemplified in
this night club scene. For the
full story see page 42.
If you have a problem or question
on audio, write to Mr. Joseph Giova-
nelli at AUDIO, 134 North Thirteenth
Street, Philadelphia, Pa. 19107. All
letters are answered.
Recording Lathe Considerations
Q. Why is it not practical or possible
to build a recording lathe with a pivoted
arm carrying the cutting head, similar
to a tonearm? It seems simpler to agree
on a standard off -set and pivot point
for the cutting device and manufacture
turntables and tonearms to this standard
than to worry about minimizing tracking error in reproduction.
If there is some great technical obstacle which makes this solution invalid,
can you tell me what it is? J. N. Perrett,
Jr., New Orleans, Louisiana.
A. For simplicity, let us consider that
the record being cut is monophonic. Under normal conditions the cutting stylus
moves along a radius, dead in line with
the center hole of the disc. The turntable is rotating, of course, and, although
the motion is circular, we can state that
motion of the stylus under modulation is
at right angles to the turntable motion.
Let us now assume that the cutter was
rotated 90 degrees so that the stylus motion under conditions of modulation
would be forward and backward. This
is in the direction of table rotation, is
it not? Can we play such grooves back?
Will there be modulation impressed on
the grooves? The answer to the first
question is yes, and to the remaining
two questions, no. The reason for this
is that nothing has been done to the
groove; they have not been made to
move from side to side. We have made
the stylus move along the path of the
spiral cut, but any tendency toward impressing modulation will be erased as the
disc turns a small fraction of an inch.
Let us see if this point can be made
still clearer. Suppose the cutter is moving toward the center of the disc from
right to left. The stylus is moving forward and back during program material.
Let us consider one cycle of modulation
and see what happens. Suppose the cutter moves the stylus forward one mil. In
other words, the stylus has moved in
the direction that the table is moving.
Even if the table were not moving, the
stylus will complete the half cycle and
come to its original starting position,
move backward, and return to rest again.
This condition will be worsened if the
2
turntable was moving. As the ,ta"ble
moves forward, the stylus moves bkkward. All signal will be erased.
Even if modulation was produced on
the disc, this modulation will be moving
in the direction of stylus travel. How
can this result in an alteration of playback stylus position in accordance with
the modulation? Clearly, it cannot.
Presumably, you are now asking what
am getting at, and how this even
relates to your question. Look at it this
way: I gave you two instances of recording head arrangements, one the conventional, and the other which is ridiculous. What you propose is that the cutter
rotate like a tonearm. If this rotation is
permitted to continue far enough, you
can see that both of my cutter arrangements will occur, with intermediate positions within which modulation will begin to appear more and more until the
cutter is in the standard position which
we are accustomed to seeing.
First of all, then, we can see that
if the cutter is forced to rotate like a
cartridge and tonearm, some modulation
will be lost. The amount of this loss
will depend upon the amount of rotation.
The loss of signal produced by this
arrangement will not be cancelled by
the tracking error of the playback assembly. All that will happen is that even
more signal loss will take place.
There is still another problem. If you
have ever used a lathe for metal work,
you know that the cutting tool must be
positioned correctly or it cannot cut the
metal being worked. The greater the
misalignment between the tool and the
moving work, the less efficient the cutting process will be. Finally we will
arrive at a point where the tool will not
cut at all but will tear the work. Further, the tool probably will be ruined.
A recording stylus is a cutting tool
ground to small dimensions, but still
basically a lathe tool. If this tool is
allowed to be used at any angle other
than the correct cutting angle, a rough
cut will result, the playback will contain
increased surface noise, and the groove
depth will be decreased.
Even if you are not familiar with the
operation of a metal -working lathe, consider what will happen if you are using
an ordinary wood chisel and turned it
in a manner other than the correct one.
Do you think you can chisel a shape as
accurately as you could by holding the
tool correctly? Or course, you cannot
hope to obtain any kind of results.
I
AUDIO
www.americanradiohistory.com
FEBRUARY, 1967
Mark of the leader...
D
Ó
0
The ultimate expression of over 50 years
of Garrard leadership, this much -imitated
but unequaled automatic transcription
turntable contains many
developments invented,
perfected and
brilliantly refined by the
Garrard Laboratories,
and now considered
essential for the
finest record reproduction.
Heavy, cast 12"
anti-magnetic turntable is dynamically
balanced with
copper weights on
underside.
11111.
Hydraulic cueing
and passe
control eliminates damage to
records or
stylus through
manual handling.
Dynamically
balanced,
counter -weight adjusted tone
arm of Afrormosia
wood and
.
aluminum for
ight weight,
ow resonance.
Low mass cutaway
shell compatible
with the most
Anti -static, dust -
repellent turntable
mat has safety
rings at 12", 10"
and 7" positions to
protect stylus should
automatic switch
be activated without record on
turntable.
advanced,ligh-est
tracking
cartridges.
Two
interchangeablespindles:
short
spindle facilitates
Patented anti skating control,
calibrated in half
gram markings, is
adjusted with
springless, sliding
weight.
m,..
manual play; long,
center -drop spindle
handles eight
records fully
automatically.
....
--
Euilt-in stylus
pressure gauge,
calibrated in quarter
gram internals,
has click -stops for
precise, audible/
visible settings.
Just two years ago, the stereo high fidelity world was introduced to the Lab 80, the first Automatic Transcription
Turntable. It was instantly acclaimed because of the significant developments it contained. These imparted professional performance capabilities never before anticipated in automatic record playing units. Now, the Garrard
Laboratories have refined and surpassed the original model with the Lab 80 Mark II, still priced at only $99.50, less
base and cartridge. It is one of five new Garrard Automatic Turntables each of them the leader in its class.
For complimentary Comparator Guide, write Garrard, Dept. AB -1, Westbury, N.Y. 11590.
Check No. 103 on Reader Service Card.
www.americanradiohistory.com
It is very expensive to make a recording lathe in such a way that it can move
smoothly across a radius; it is easier
to pivot the entire assembly as you have
suggested. In fact, inexpensive recorders
are based on that very idea. Such cutters are built to keep error to a minimum, but discs cut under these conditions are not uniform as to cut or
signal-to-noise ratio. Distortion increases.
The idea behind the manufacture of
these instruments is not to obtain better
playback quality, but to make their price
attractive to hobbyists.
My first cutter featured such a cutting
system. Rather good discs could be cut
on that machine, but they cannot compare to my present cuts, made on a lathe
which allows the cutter to move in a
straight line along a radius.
Although I have indicated that your
idea is not feasible, I still must say that
it represents good thinking. I believe
that I would have reasoned along these
same lines in my early days of cutting
discs.
Noisy Preamplifier?
When a Pioneer Speaks
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That's when you'll hear the optimum in tonal quality
reproduction at its faithful best.
You can always count on Pioneer speakers and speaker systems
to deliver a quality performance. Every time. All the time.
Made by the world's largest manufacturer of speakers, this
premium audio equipment is available at popular prices.
from the unique,
And you can select from many fine models
handsome metal -grilled CS -24 Auxiliary Wall Speaker to the
efficient, compact CS -20, CS -52 and the Ultimate 5 -speaker
CS -61 Bookshelf System. All carried only by franchised dealers.
A word from you and we'll send literature and the name of your
nearest dealer.
-
(A) CS -62
Bookshelf
3 -way
speaker sys-
(C) CS -20 Compact 2 -way speaker system.
(3 speakers). Oiled walnut encloMeas. 251" x 153/1" x 111%:,
Oiled walnut enclosure. Meas. 131/4' x
8" x 81h", retail price: $35.00.
retail price: $142.00.
(D) CS -24 Ultra -thin wall or bookshelf
(B) CS -61 Bookshelf 3 -way speaker sysspeaker system. Unique metal -grilled
tem (5 speakers). Oiled walnut enclooiled walnut enclosure. Meas. 161/2" x
sure. Meas. 241/4" x 16'yg" x 131/4",
101/2" x 43/4", retail price: $27.75.
retail price: $175.00.
(E) CS -52 Compact 2 -way speaker system. Oiled walnut enclosure
with gold metal trim. Meas. 131/2" x 81/4" x 81/2". retail price: $59.95
tem
sure.
PIONEER ELECTRONICS U.S.A. CORPORATION
CO140
SMITH AVE. FARMINGDALE, LONG ISLAND, N.Y. 11735
(516) 694-7720
E
Check No. 59 on Reader Service Cord.
www.americanradiohistory.com
Q. Just today, I began to notice a
loud sound in my speakers whenever 1
tapped my preamplifier lightly or even
the shelf it is on. It also happens when
I turn the selector knob, the bass or
treble controls, etc. In other words, anything that jars the preamplifier the slightest produces a loud break-up in my
speakers which sounds like what I
would get when I would tap my finger
against a microphone.
My first impression was that something
was loose. My superficial examination,
however, could discover nothing obvious.
The six tubes extending through the back
appear to be seated well. Tapping each
one of them did not seem to pin point
the problem. I checked each plug; they
are all in place. Jiggling each one of
them produced the noise, which did not
identify a particular plug-but only that
I was vibrating the chassis in general.
Volume has no effect either. The noise
is quite loud even with the volume at
minimum. It takes place regardless of
where the selector switch is set.
Is there something I might check out
on this myself or is this a problem best
handled by a service station? Samuel J.
Neiditch, Highland, California.
A. Because I am not familiar with
your background, I am not in a position to say whether or not you can repair the condition described in your
letter. However, I can make some suggestions as to how you might go about
locating the general area of the trouble.
Perhaps unknowingly, you have already done some trouble -shooting which
has produced worthwhile information.
You have learned, for example, that
the difficulty is not the phonograph preamplifier stage of your equipment. Further, you have discovered that it is not
occurring in any stage ahead of the
volume control. Now you can concentrate on the problem of localizing the
trouble in the remaining preamplifier
stages.
AUDIO
FEBRUARY, 1967
D-19 E / 20 O
is a cardioid microphone for high quality recording and sound reproduction, and provided with bass roll -off switch for
exceptionally clear speech intelligibility and excellent output for above average "reach." It features
effective front -to -back discrimination and a non-
metallic diaphragm-preventing popping and
harshness on close-ups.
TECHNICAL DATA
Frequency range
Frequency response
Sensitivity
Impedance
Dimensions
Weight
40-16,000 cps.
± 3 db
-
53 db
200 ± 20%
73/4" long by l'Áe" diameter
7 ounces
Here are two economical microphones for a variety
of recording, broadcast and public address applications. An accessory W-24 Windscreen is available
for the D -19E/ 200; also fits the D-24E microphone.
Truly noise canceling, the D -58E microphone is the
ideal choice for sportscasts, industrial uses or any
similar noisy environment.
Send today for data sheets and prices.
58E
Dis a noise -cancelling microphone
limited to the speech range and offers crisp, clear
speech reproduction, for maximum intelligibility. It
effectively discriminates against any sound originating beyond 5" from the microphone.
TECHNICAL DATA
Frequency range
Sensitivity
Impedance
Dimensions
Weight
Goose neck
70-12,000 cps.
-
58 db
200 or 60 ohm ± 15%
1%" long by 1'î;." diameter
1.1 ounces
8" or 20" length (optional)
MADE IN AUSTRIA BY AKG GMBH.
No'ek6
PROFESSIONAL
SOUND PRODUCTS
NORTH AMERICAN PHILIPS COMPANY, INC.
Professional Products Division, 100 East 42nd St.. New ,York,
N. Y. 10017
Check No. 61 on Reader Service Card.
AUDIO
FEBRUARY, 1967
5
(Photograph by courtesy of the Royal Festival Hall)
... and in your own
armchair
Starting from the volume -control stage,
remove each tube. See at what point the
tapping disappears. You will finally arrive at a tube, which, when it is removed from the socket, will result in no
noise being heard when the preamplifier
chassis is tapped. The actual trouble will
be found in the stage associated with the
tube you last removed from the socket.
First of all, check the tube. Probably
the surest way to check a tube under
these conditions is to replace it with one
which you know to be in good condition.
If the tube proves to have been good,
check the electrolytic capacitors to see
that none of the ground or 'hot" terminals have become loose. Check all
solder connections in that stage, including those in the decoupling circuitry,
which you might normally associate with
the power supply. My guess would have
to be that something has been poorly
soldered or that you have a defective
component, probably an electrolytic capacitor.
If the trouble continues even though
all tubes have been removed from their
sockets, you will know that the trouble
is in your power amplifier or in the
cables associated with the preamplifier
and the power amplifier. If the trouble
appears to be in the last stage or so,
it is also possible that it is a result of
cable connections rather than internal
in the preamplifier.
Sometimes the filament wiring is such
that it is inadvisable to remove tubes
from their sockets as described here. By
doing so, you may cause an excessive
rise of filament voltage applied to the
other tubes, resulting in damage. Further,
other tubes may have been connected in
series with the one you took out, and
these tubes will be extinguished, leading
possibly to a false conclusion as to the
troubled stage.
In these instances, it is best to short
the grids to ground successively. This
has the further advantage of localizing
the trouble to a particular stage rather
than to a particular tube. Most tubes
encompass two stages.
Cable Losses
Not so far-fetched with electrostatic loudspeakers and
stereo broadcasts.
Properly handled, stereo radio is a vital step towards the
closest approach to the original sound.
Ask your Hi-Fi Dealer for details of the QUAD range (including
the multiplex decoder for stereo broadcasts) or write to:
The Acoustical Manufacturing Co. Ltd., Huntingdon, England.
(2).Ai
6
for the closest approach to the original sound,
Check No. 58 on Reader Service Card.
www.americanradiohistory.com
Q. For the past six months I have
been making my own patch cables.
They have all worked satisfactorily
using high -impedance sources. Recently, I had occasion to compare my
patch cords with the store-bought
variety. It seems that I am getting
greater losses in general and per distances than the store-bought types
present. I am using regular shielded
coaxial cable which is stamped 75
ohms. I was always under the impression that shielded cable is all alike.
This is apparently false.
Please give me the characteristics
or specifications of lower -loss audio
cable. LT (jg) George J. Korinek,
FPO, San Francisco, California
A. The most significant problem
when high -impedance lines are used
is the loss of high frequency response
as a result of the capacitance between
AUDIO
FEBRUARY,
1967
LE MANS IS CHILD'S PLAY COMPARED TO
"FOUR CONCERTOS FOR HARPSICHORDS AND ORCHESTRA"
The Shure V-15 Type II phono cartridge
must be much more trackable than a Lotus
Ford. This seemingly silly simile has significance, however, when one fully appreciates the importance of trackability in
providing crisp, clear, distortion -free
sound from a// of your recordings. The
ascents and descents, jarring side swipes,
abrupt turns of a Grand Prix course are
widely known. (Other analogies we might
have used are the slalom, the steeplechase,
the bobsled). Not yet as well known has
been the curious fact that the grooves reproducing high level recordings of orches-
tral bells, harpsichords, glockenspiels,
drums, pianos-through which the cartridge must wend its melodic way-are
even more tortuous, more punishing.Thus,
the much talked about "compliance" and
"mass" of past evaluations are now merely
parameters of design-whereas "track ability" isthetrue measure of performance.
For your entry into the era of high track ability, for an experience in listening you
will find most astonishing, ask your Shure
dealer to demonstrate the Shure V-15
Type II Super-Track*at $67.50, the Grand
Prix elite among cartridges. It maintains
contact between the stylus and record
groove at tracking forces from 3/4 to 11/2
grams, throughout and beyond the audible
spectrum at the highest velocities encountered in quality recordings. Shure Brothers, Inc., 222 Hartrey Avenue, Evanston,
Illinois 60204
T.M.
Check No. 62 on Reader Service Card.
AUDIO
FEBRUARY, 1967
7
lane
without
Koss slereonhones?
who'U gamble it?
don't have to gamble on taping sessions anymore.
Plug Koss Stereophones into your recorder and you
monitor every sound as it's recorded. Overload? Distortion? You'll catch it immediately. Microphones properly
placed? You bet! You'll hear it all with dramatic Koss
You
Stereophones.
Best for Editing and Playback, too.
Model PRO -4A
$50.00
Model KO -727
$34.95
Model SP-3XC
$24.95
KOSS ELECTRONICS INC.
2227 N. 31st Street, Milwaukee, Wis. 53208
Koss -Impetus, 2 Via Berna, Lugano, Switzerland
8
Check No. 57 on Reader Service Card.
the center conductor of the cable and
its shield. Most of the time, and for
most of the runs encountered in home
installations, these losses are unimportant because the circuits at the
`sending' end of the line are cathode follower or emitter -follower circuits,
and the capacitive reactance will be
higher than the impedance of the
cathode follower. This will be true
even at the highest audio frequencies.
If you plan to run a line which will
extend over 100 feet or more, you
should consider the use of line transformers. There again, the capacitive
losses will be of little consequence.
If the impedance of the line is very
low, as is true when loudspeakers are
involved, capacitive losses again are
of little or no importance even over
great distances. However, the ohmic
resistance of the wire making up the
cable will play a big part. There will
be a voltage division action between
the amplifier, the cable and the speaker at the other end of the line. If a
run is to be of considerable length,
you must use either a large wire
gauge or use line-to -voice coil transformers at each end of the line so
that the impedance will he high
enough so that the losses in the line
will not be significant.
If you are using a crystal microphone, the capacitive losses will play
a great part in the overall picture. The
microphone is capacitive in nature.
It will, therefore, be a capacitive voltage division action between the capacitance in the mike and that of the
cable. Further, long, high -impedance
cable runs such as this are susceptible
to hum pickup.
Phonograph cable leads are subject
to loss of high -frequency response if
their length is too great. Their capacitance is added to the internal capacitance of the cartridge. If this capacitance is sufficiently large, it will
resonate with the inductance in the
cartridge at some audio frequency and
there will be a peak produced, and
above this peak there will be a falloff of highs. The load resistor placed
across the cartridge is not meant as
an impedance -matching device as
many people believe. It is intended
to lower the Q of such a resonant
circuit, leading to a reduction of the
size of the peak.
Your cable problem, therefore, resolves itself into locating lower capacity line than you are presently
using. 75 ohm coaxial cable has a
considerable amount of capacitance
per foot. I am quite sure that a good
grade of mike cable will contain less
capacitance than you are now using. Æ
AUDIO
FEBRUARY, 1967
This ad is supposed to give
you a reason for listening to the
Fisher700-Tsolid state receiver.
We decided to give you several:
Amplifier section:
Music power (IHF)
4 ohms
8 ohms
Tuner section:
120 watts
90 watts
Harmonic distortion (1 kHz)
At rated output
3 db below rated output
0.8%
0.3%
distortion (60:7000/4:1)
At rated output
3 db below rated output
0.8%
0.3%
IM
Hum and noise
Volume control (min.)
Phono input (6 mV ref.)
Aux. input (400 mV ref.)
-1
1.8µV
Harmonic distortion
(100% mod. and 400 Hz)
0.4%
Stereo separation (400 Hz)
40 db
Signal-to-noise ratio
(100% mod.)
70 db
Selectivity
(alternate channel)
50 db
Capture ratio (at
Frequency response 10-70,000 Hz
+0,
Usable sensitivity (IHF)
db
-80 db
-55 db
-65 db
Input sensitivities
(at 1 kHz, for rated power at 4 ohms)
Phono (low)
3.5 mV
Phono (high)
10 mV
Tape Head
2.5 mV
Auxiliary (low)
200 mV
(high)
400 mV
1
mV)
Spurious response rejection
(100 M Hz)
2.0 db
90 db
PRICE, $499.50 (CABINET $2.4.95). FOR MORE INFORMATION, PLUS
A FREE COPY OF THE FISHER HANDBOOK. WRITE FISHER RADIO
CORPORATION, 1122 45th ROAD, LONG ISLAND CITY, N. Y. 11101.
The Fisher
it justice.
No ad man can do
Check No. 97 on Reader Service Card.
AUDIO
FEBRUARY, 1967
9
LETTERS
JOIN THO!E N
Crusade for Transcription Quality
Thorens turntables will not permit anybody to stack records
against you. Thorens one -record -at -a-time assures top performance always. Today, the Thorens TD 124 Series II is the
and unmatched
finest transcription turntable on the market
for mono- and stereo -performance. And silent, two -speed
lowering device
the
latest
safety
Thorens TD 150AB brings you
with pneumatic damping action. All Thorens turntables carry
the Elpa Seal of Endorsement. Look for it. Write for the Elpa
catalog. Dept. 10A2.
-
ELPA MARKETING INDUSTRIES, INC., NEW HYDE PARK, W.Y.
Stereo Indicator
SIR:
11040
Check No. 56 on Reader Service Card.
This is our idea
of a well rounded
speaker.
If my memory serves me properly,
quite a long time ago you had a schematic for a stereo light. This was actuated by a relay circuit in a stereo tuner
when a stereo broadcast was on the air.
Please tell me how I may obtain either
a copy of the article or a copy of the
issue in which it appeared.
SIDNEY LANDAU,
2137 West Huntington Ave.,
Anaheim, Calif. 92801
(Not us, we think. Only article on a
stereo indicator that we can locate was
in Popular Electronics in September 1963.
You might inquire from them, at 1 Park
Avenue, New York, N. Y. 10016).
Ribbon Microphone Modification
SIR:
tion, plus broader sound
propagation across the
entire spectrum. All in
Forget the frills of a
hand -rubbed walnut finish, statuesque originality and language like
that! When you buy a
speaker, you're buying
erformance. Sound!
The Royal Grenadier
all, it rounds out the
most significant advances in stereophonic
reproduction! The fact
that we've added a flawless imported marble top
9000 is our idea of a
true-to-life speaker sys-
is just so much more
icing. For color literature and nearest dealer,
tem. Its revolutionary
die-cast divergent acoustic lens assures fuller
frequency and separa-
NS REWMTAVE..MEDEx City. N.Y
Check No. 88 on Render Sery ce Card.
We are trying to track down an article
which appeared in AUDIO about a year
ago concerning a firm here in the Boston
Area which did some work on an RCA
ribbon microphone in that they were
able to step up the output by installing
a transformer, and other modifications.
At the time, the article in question
was found to be very interesting, but we
laid it aside in some manner and it became lost. We would like to get another
copy of the issue, or a reprint of the
article.
RICHARD MILES,
131 Farrington St.
Wollaston 70, Mass.
(We can do better on this one, although
we do not have any copies of the issue
in question. The article was entitled, "A
'New' Ribbon Microphone," and was by
Charles P. Fisher. It appeared in the
August, 1965, issue. If it is important,
we could furnish photocopies of the article. ED.)
The new Sony Solid State 350 adds professional performance to home entertainment systems
Selecting the brilliant new Sony Solid State 350 to fulfill
the stereo tape recording and playback functions of your
professional component music system will also enduringly compliment your impeccable taste and passion for
music at its finest. With an instant connection to your
other stereo components, the versatile two -speed Sony
350 places at your pleasure a full array of professional
features, including: 3 heads for tape and source monitoring. Vertical or horizontal operation. Belt -free, true
capstan drive. Stereo recording amplifiers and playback
SONY
pre -amps. Dual V U meters. Automatic sentinel switch.
Frequency response 50-15,000 cps -±- 2db. S.N. ratio
plus 50db. Flutter and wow under 0.15%. Richly handsome gold and black decor with luxurious walnut
grained low profile base. This remarkable instrument
is yours at the equally remarkable price of less than
$199.50. Should you want to add portability to all
this, there's the Model 350C, mounted in handsome
dark gray and satin-chrome carrying case, at less than
$219.50. For information write Dept. 17, Superscope, Inc., Sun Valley, Calif.
SUPERSCOPE
The Tapeway to
Stereo
m
Portable Model 350C
Check No. 71 on Reader Service Card.
AUDIO
FEBRUARY, 1967
11
Fundamental AUDIO
MARTIN LEYNARD
Loudness and the Decibel
We hear frequencies logarithmically,
as we discussed last month. Our per-
Big ccnsole saands f
shelf ize speal.e systd
.
1?
ception of frequency differences is based
on the proportional, rather than the
absolute differences between them.
For example, we hear the 440-Hertz
difference between A (440 Hertz) and
A' (880 Hz.) as an octave, because the
higher frequency is exactly twice the
lower. But if we jump an additional 440
Hz., from 880 to 1320 Hz., we hear the
difference as only a fifth (A" to E');
farther up the scale, the same 440 -Hz.
difference can be a single whole tone, the
difference between A"' (3520 Hz.) and
i
imposrble?` Nt, it so
s<:r
But, UTA
magic doesne. st
there wit the ail new PRO. L}
the chameleon tl-e PRC also
change's colos io< match any
changing room decor_ The front of
this beautiful Walnut cabinet has
a snap out gr Ile, which can be
B"'(3960).
speaker high -compliance system
attests to the real magic of UTAH
electronic sound eng neering.
Our perception of sound intensities
hear a sound as "twice
as loud" when its actual intensity increases ten -fold. ("Intensity," of course,
refers to the absolute sound level, while
"loudness" is our perception of it.) An
average house, with a sound pressure
level of perhaps 0.02 dynes per square
centimeter, sounds only half as noisy
to us as a noisy office (0.2 dynes/cm2),
and a noisy factory, or subway train
(2.0 dynes/cm2) sounds twice as loud
as that.
Model PRO I $94.95 net
The Decibel
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It's dimensions cf 12" x 12" x 24"
pack the finest acoustical engiveeting found anywhere.. This 3 -
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features:
Bookshelf size, console
sound
Snapou: accent grIie
Acoustic suspension
highcornpliance woofer
in a sealed cabine:
Handmazbed 3/.rß walnut
veneer cabinet
Advanced acoustic
engineering
Components
Utah
Speakers, a 10" vecfer,
two 31" tweeters
(adjustable level}
-
-3
Sealed enclosuro-heavily
damped with fiberglass
Power rating-40 setts
-8
Impedance
onus
Frequency Responze30/19.500 cps
.
Sound intensity (in air) is usually
expressed by the pressure of the sound
wave, in "dynes/cm2" or "microbars."
Loudness is usually expressed in decibels. And since audio is more concerned
with what we think we hear than what
we're really hearing (the object is to
hear the Philharmonic in your living
room; not to have them there), we'll
be using the decibel quite frequently
from here on in, sound pressure measurements almost never.
The decibel takes its name, a trifle
indirectly, from Alexander Graham Bell,
whose main interests in life were understanding and improving human hearing
(his wife, incidentally, was deaf), and
whose invention of the telephone might
be called, in a way, a by-product of these
interests. When early experimenters
found a ten -fold increase in sound intensity equal to a doubling of loudness,
they called this difference "one bel."
The bel is too large a unit to work
with comfortably, so the "decibel"
1./10 bel-was established as the standard measure of relative sound levels.
The decibel ("dB," for short) is indis-
-
<--
12
pensable for two reasons: Being a logarithmic unit, it greatly condenses numbers we must work with; we may call
the range from the threshold of hearing
to the threshold of pain "0.002 to 200
dynes/cm2" or refer to it as a relative
energy range of 1,000,000,000,000 to 1
we can call it 120 dB and be done
with it. And because our hearing is also
logarithmic, it corresponds to our perception of sound. One decibel is also,
by a handy coincidence, just about the
minimum difference in sound level that
human ears can perceive.
Unlike the microbar, which is an absolute measurement, the decibel is a
relative unit, meaningful only when related to some absolute level. Thus, "a
level of 7 microbars "refers to a specific
sound level, and "an increase of 6 dB"
describes a proportional change in sound
level, but "a level of 6 dB" is, without
some implicit or explicit reference level,
meaningless. But in contexts where levels
are frequently given in decibels referred
to some standard sound intensity, the reference level tends to become implicit.
You may usually assume, for example
that in any discussion of acoustics or
hearing-including future FUNDAMENTAL
Aunto columns,-sound levels given in
dB are being implicitly referred to the
threshold of hearing, .0002 microbar.
When we say that a decibel is a tenth
of a bel, we must keep in mind these
units' logarithmic character. Although the
difference between 1 microbar of sound
pressure and 10 microbars is 10 decibels
-one bel-we must not assume that 2
microbars is 1 dB louder than 1 micro bar, 3 microbars are 2 dB louder and
so on. Nothing of the sort! Actually,
every time we double the sound level,
we raise it 3 dB. For example, 2 micro bars are 3 dB louder than 1, 4 micro bars are 6 dB louder than 1, and 8
microbars are 9 dB louder than 1 (and
6 dB louder than 2)
Thus, the difference in output capabilities of a 50-watt amplifier and a 25watt amplifier is only 3 dB louder,
(3.0105 dB to be exact) not "twice as
loud," as some think (and you'd probably listen to either at a 1- to 5 -watt
level most of the time anyway) .
All of the above statements on how
we hear are true only for certain conditions of listening. Our perception of
sound will vary according to the type of
sound, its frequency, its level, our own
age and sex, the noises we hear at the
-or
.
Check No. 55 on Reader Service Card.
AUDIO
FEBRUARY. 1967
At $149.50,
less cartridge and base,
your hi-fi dealer should
be able to demonstrate
the new Miracord 50H
as decidedly superior
to any other automatic.
Insist upon it!
Exclusive features include hysteresis motor and stylus -overhang adjustment plus anti -skate and
cueing dynamically balanced turntable and tonearm, and feathertouch pushbutton operation.
For complete details, write: Benjamin Electronic Sound Corp. Farmingdale, New York 11736
r
(1!
r
FAIRCHILD MASTER
TAPE IMPROVEMENT SYSTEM
FAIRCHILD MTIS with "focused -gap"
head design reduces bias -induced noise
to a point where it is no greater than 1.5
db than the noise of virgin or bulk -erased
tape. FAIRCHILD MTIS has an S/N ratio
of 72 db on one track of a 4 -track 1/2"
tape. FAIRCHILD MTIS increases the recording level by 4 db over present standards, with the lowest harmonic, intermodulation, and cross -modulation distortion
of only .5%. Only the FAIRCHILD MTIS
comes in a compatible, convertible package allowing you to update your present
tape transports to the highest quality
"state of -the -art" recording standards.
rri11111111171...1111
FIGURE 1.
Noise
Deafening
Very loud
-110-
-
THE REVERBERTRON
The new compact reverberation system which
gives your station that
Moderate
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.
-
Faint
-
-
-
1,000,000,000,000
10,000,000,000
90
--
1,000,000,000
80
-
100,000,000
70
--
10,000,000
60
--
1,000,000
50
--
100,000
40--
10,000
--
1,000
30
Sound
pressure
dynes/cm2
--
20 --
100
--
10
--
Threshold of pain
Thunder
Gunfire
Pneumatic drill
Steam whistle
Large machine shop
20
Subway
Busy street
Noisy factory
Inside aeroplane
Loud public address system
2
Noisy office
Suburban train
Typewriters
Radio set-full volume
Average factory
--
0.2
--
0.02
-
0.002
Large shop
Average office
Quiet motor car
Quiet office
Average house
Public library
Country road
Quiet conversation
Rustle of paper
Whisper
Quiet church
Still night in the country
the pacemaker in proWrite to FAIRCHILD
fessional audio products for complete details.
-
FAIRCHILD
RECORDING EQUIPMENT
Very faint
-
10
1
CORPORATION
Typical examples
200
100,000,000,000 -
100-
FAIRCHILD CONAX
Loud
Relative Levels of Typical Sounds.
Relative energy
dB
120-
_---'--ff
The world -accepted way to control high
frequency spillovers in FM due to pre emphasis. Lets your station maintain real
high levels even with brass and crashing
cymbals and still avoid FCC citations.
graphs represent the minimum audible
sound, while the top line of Fig. 2a
tells how loud a sound will cause pain
at any frequency.
"Zero" on the sound -level scale in
each case is 0.0002 microbar of sound
pressure, the figure usually quoted as
the threshold of hearing. But note that
this is truly the threshold only in the
vicinity of 1000 cycles-at 30 cycles, for
example, the minimum audible sound
is 60 dB higher (about 0.2 microbars).
There is some evidence, in fact, that this
curve could be continued down to frequencies usually considered inaudible,
and that a 2 -Hertz note can be heard
-but only at a level 135 dB higher than
that at which a 1,000 -Hertz note becomes audible (yet at 1,000 Hz., 120 dB
is the pain threshold)!
What's more, at very low levels, even
our statement that "a level change of
10 dB corresponds roughly to a doubling
of loudness" becomes untrue: at low
levels a 10 dB level change is perceived
as a tripling of loudness, and at the
same time as the sound, and so on. One
of the most important of these variations is the change in loudness perception with changes in frequency and intensity.
Now the Phon Begins
As you can see from the table in
Fig. 1, the ear's sensitivity covers a
sound intensity range of one thousand
billion to one. But experimenters have
determined that the ear's sensitivity falls
off as frequencies get lower (and, to a
lesser extent, as they rise) and that this
effect is more pronounced at low sound
levels than at high ones.
Figure 2 shows these changes in hearing, as reported by experimenters in
the U.S.A. (Fletcher and Munson, Fig.
2a) and England (Churcher and King,
Fig. 2b). While the curves differ in detail, they tell much the same story.
Each line on the graph represents the
sound pressure level (vertical scale) necessary to produce the perception of a
given loudness at any frequency (horizontal scale). The bottom lines of both
Sound -proof room
Threshold of hearing
0.0002
10-40 45th Ave., Long Island City 1, N.Y.
AUDIO
Check No. 54 on Reader Service Card.
www.americanradiohistory.com
FEBRUARY.
1967
WORTH WAITING FOR!
DYNACO STEREO 120
The Dynaco Stereo 120-the most anxiously awaited
high fidelity product in years-is now at many dealers.
After more than 3 years of intensive development, this
great new transistorized amplifier offers the same high
level of quality, dependability and economy which have
become synonymous with the Dynaco name.
The Stereo 120 delivers 60 watts per channel continuous power with performance specifications and
with a purity of sound rivalled only by Dynaco vacuum
tube amplifiers which have had a 10 year reputation
for excellence. Its frequency response, distortion,
power response, transient response, overload characteristics and phase characteristics are all outstanding. Its sound quality is impeccable, with not a trace
of the unnatural brightness of "transistor sound."
Many new Stereo 120 owners feel it surpasses all
other amplifiers, tube or transistor.
Complete specifications are available on request
from Dynaco, but some of the Stereo 120's special
attributes are:
A fully regulated, rock -solid power supplycapable of delivering unchanging supply voltages
under all power demands and line fluctuations,
yet its protective circuitry acts faster than a fuse
in case of accidental abuse.
Electronic instantaneous protection against overload, open or short circuits (even at full power)
on each
amplifier.
entaiaINCH 3912
addition to assuring extremely low distortion
at high power levels, patented Dynaco circuitry
virtually eliminates the usual transistor distortion at very low power levels.
Modular construction for surer, faster kit assembly and service when required, using prefabricated circuit -tested etched circuit boards.
Common output ground permits the use of most
headphone junction boxes, multiple speaker installations, and optional 3 speaker stereo
In
systems.
All silicon transistors and computer -grade electrolytic capacitors for permanent loudspeaker
protection and superior reliability.
No
adjustments-ever!
The Dynaco Stereo 120 is ideally matched to the
Dynaco PAS -3X perfectionist's preamplifier. The combined distortion of this pair over the audio frequency
range at most useable power levels can be expected
to stay below 0.1%-yes, one -tenth of one percent!
We do not feel that further commentary on this com-
bination is required.
The demand for the Dynaco Stereo 120 is very
great. Please be patient if your dealer cannot fill your
order immediately. The factory assembled amplifier is
$199.95; the kit version now being released is
$159.95 and requires about 5 hours to build.
POWELTON AVENUE PHILADELPHIA, PA. 19104
Check No. 66 on Reader Service Card.
AUDIO
FEBRUARY. 1967
15
140
Nee,11
LOUDNESS LEVEL
Up-
120
100
100
...............
z
grade
your
90
80
w
>
w
w
70
J
Fig. 2a. The Fletch- g
z
o
o
in
50
40
40
30
20
20
10
0
o
20
1000
LOUDNESS LEVEL IN PHONS
120
110
9`
m
100
100
>
1.1
w
cc
80
80
70
o
en
an
10
á
6
0
o
z
unique way of making
it sound better.
Perhaps it's the ease with which EMI
loudspeakers project sound. So smooth
and natural,
it seems to float
on the
Fig. 2b. The Church
er -King hearing `
curve.
-
\
60
50
40
40
30
20
20
10
0
0
air
in all its concert hall glory. Filling the
20
100
Or perhaps, it's the deep bass, the incomparable realistic midrange and the
full, silky highs.
Or it could be the subtle detailing of
their transient perfect response that
catches you unawares.
So, for better sound from your receiver
or amplifier, come on up to EMI loud-
speakers.
There's an EMI loudspeaker
to meet any requirement and
budget. From $49.95* to
EMriscoPE
Scope Electronics Corporation
470 Park Avenue South
New York, New York 10016
Also available in Canada.
1000
'
,
,
10000
:0000
FREQUENCY IN HZ
room.
$395.00*
*Slightly higher in South and West
'00000
140
w
a
MOO
FREQUENCY IN HZ
sound
Whatever your receiver or amplifier is
capable of doing, EMI loudspeakers have
-
60
60
ÿ
er-Munson hearing w
á
curve.
PHONS
120
very lowest levels it is heard as a change
in loudness by a factor of nearly 20.
So it would seem that the decibel is
an imperfect measure of loudness,
though still a most convenient measure
of sound intensity relationships and (assuming an explicit or implicit reference
level) of sound intensities as well.
Now each of the curves in Fig. 2 is
an "equal loudness" curve; that is, any
two points on any curve will sound
equally loud. Based on these curves, we
get a new unit, of loudness, not intensity, called the phon. A sound's loudness in phons is equal to the loudness,
in dB relative to the hearing threshold,
of a 1,000 Hz. pure sine -wave tone.
To give an example, an 80 -dB, 50-Hz.
sine -wave tone and a 70 dB tone at
about 8,000 Hz. both sound as loud as
a 1,000 Hz. tone at 60 dB above 0.0002
microbar. All three tones are therefore
defined as having a loudness level of 60
phons (phons and dB are the same for
1,000 Hz. sine waves), and the curve in
Fig. 2b that runs through these three
points
is called the 60-phon curve.
As you may gather from the stress
placed on sine waves in the preceding
paragraph, our perception of loudness
is different for different wave -forms, too.
But since the phon measures our perception of loudness, it can be applied as
easily to square waves, triangular waves,
or complex musical waveforms as to pure
sine wave tones.
You may have noticed that the level
controls of some audio amplifiers are
labeled "volume" while others are labeled
"loudness." Loudness controls introduce
some bass boost at low settings, to compensate for the loss in low -frequency
hearing that we've just been discussing;
volume controls merely change level
without introducing bass compensation.
The pros, cons, and rationale of loudness controls will be the subject of a
future chapter. Our next topics, however,
will be waveforms, timbre and distortion.
Æ
Check No. 53 on Reader Service Card.
AUDIO
16
www.americanradiohistory.com
FEBRUARY, 1967
interchangeable center
spi- dies for manual or automatic play.
Dynamically balanced, resiliently mounted 4-pole
motor shielded from hum.
The heavy-duty, constant
speed design assures minimum wow and flutter.
(wired for either 110 or
220 volt operation-easily
convertible to
50
operation).
cycle
Low mass tubular alumi-
num pickup arm is perfectly counter-balanced
both horizontally and vertically less susceptible to
external shock, even tracks
upside down! The arm is
-
supported on virtually
frictionless pre-loaded horizontal ball bearings for
sensitive and accurate
tracking.
Resiliently mounted, coarse
and fine vernier adjustable
counterweight. Exclusive
micrometer stylus pressure
adjustment that permits 1/3
gram settings from 0 to 6
grams.
Automatic lock secures the
pickup arm whenever the
machine is "off." Another
exclusive BSR development
prevents jamming-without having to reset the
arm! The controls are easy
operating for manual or
Cueing and pause control
automatic selection of 7",
10" or 12" records at 16, 33,
45 or 78 rpm.
lets you select the exact
band on the rscord you
can eve. "pose" at any
-
point, and then gently
lower the stylus into the
same groove.
All Kidding Aside, would you spend $49.50 for a $74.50 automatic turntable?
You already know that the British are experts at
building the world's finest changers. And now
there's new automatic turntable available in
America from BSR Limited. It's the McDonald 500
Automatic Turntable-$74.50 features for $49.50.*
The reason it's on its side? The McDonald 500
..
BSR
has a truly adjustable, counter-balanced arm ... a
feature you would expect to find only on the $74.50
model. Look over the other McDonald 500 features,
too. Think about all the records you can buy with
the money you save by getting the McDonald 500*Suggested Retail Price
precision crafted in Britain.
McDONALD
500
BSR (USA) LTD, McDONALD DIVISION, ROUTE 303, BLAUVELT, N.Y. 10915
Check No. 67 on Reader Service Card.
www.americanradiohistory.com
AUDIO
job is plenty big enough already. My
long-time favorite FM, /Q antenna, which
the JFD replaces, was a six -element,
half -wave model and pretty fancy, at
that, when it first went up on my roof.
(Now, there's also a 12 -element FM/Q,
as well as others.) As mentioned last
month, that smaller FM/Q was superb
for distant -fringe mono FM and it should
still be plenty adequate for the thousands
of square miles of middle -fringe stereo
surrounding our big cities, all over the
place. That's where most of us live. But
if your problem is tougher, like mine,
then you must pay for better reception
in terms of bigger size. No way that I
know of to avoid it. That's what comes
with stereo progress!
M.
Edward Tatnall Canby
Saturation Logging
No Comparison
When I first unpacked the JFDLPLFM 10-I mean the JFD . LPL .
FM
10-out of a neatly streamlined fold -up shipping carton and laid
it down on my front lawn (this was
in warm weather last fall), my heart
sank. It looked bigger than the house.
It was incredible. Enormous! The lawn
wasn't big enough to hold it. I had hys.
The new antenna that I put up on
my old rooftop mast, as described last
month, was deliberately chosen by me
because it incorporated a new design
principle which had me intrigued-the
so-called log -periodic configuration, developed under government auspices, if
I am right, which has been adapted to
home TV antenna systems and now,
finally, to the broadcast FM band. It
sounded to me like the answer to my
far -fringe stereo problems. The design
is supposed to provide (note my caution!) unprecedented sensitivity over a
wide range of frequencies, as wide as
you want. That's something.
Well, I'd like to say outright that logperiodic is the answer to my prayers,
and maybe yours too. I can say that it
most certainly is an answer! I am more
than delighted with what I have on
hand, and I seem to discover even more
signal strengths, new usable stations, new
clarity and separation, every day, and
a really astonishingly complete satisfaction (thanks also to the Scott 312 tuner
operating out of the antenna) in respect
to the crucial far -fringe stereo reception.
But I've only tried one antenna.
It is the JFD LPL-FM10 (will somebody please tell them to stop the alphabet soup?), senior FM model in a line
of FM antennas, both FM and TV, which
incorporate the log-periodic principle. As
the name murkily implies, it is a ten element job. (The line also includes 4,
6 and 8 -element antennas, for varying
degrees of fringidity, so to speak.) Moreover, this one is a full -wave affair, speaking laterally. That is, its sidewise arms
are twice as long as the corresponding
members on the usual half -wave antennas
found everywhere today, which range
from the home-made indoor folded dipole all the way up to the most complex
pro models. Full -wave is a fine idea,
except that it's BIG. Has to be, to match
the FM frequencies.
Ten elements, full -wave! That isn't the
theoretical maximum size, I'm sure,
18
though it's plenty big. The TV versions,
covering all the bands, and those which
also include FM radio, have many more
elements than 10; but thanks to the
higher TV frequencies involved, the arms
are mostly much shorter. So your multi element TV antenna will fit on your
rooftop without spreading sidewise onto
your neighbor's roof.
Flagpole
I suppose you could treat yourself to
a super-multiple element FM antenna,
say a couple dozen arms, if you owned
three houses in a row, and lots of back
yard space. The middle house would
hold up the antenna and it would have
to be steel reinforced, of course. I mean
the house. For a rotator, I figure, you'd
buy up an old traction motor, the kind
they used to run trolley cars. Massive,
solid and slugging. For a mast you'd
want-of course-a ship's mast. A big
ship. Or maybe a second hand municipal
flagpole, vertical -type, the kind that you
find in city parks, surrounded by fountains and plazas. 'Bout a foot thick at
the base.
.
.
.
.
.
.
terical thoughts about the tail wagging
the dog and then, instantly, more practical ones concerning the inevitable Big
Wind that hits my exposed mountainous
area. I could see the thing soaring off
into the nearby forest like some sort
of hoisting helicopter, toting my roof
along with it underneath. In fact, my
assistant was worried enough to replace
all the old guy wires with new aluminum
stuff, just to be sure that the roof would
go along in one piece if things did blcv
away.
I shouldn't have worried. Norb, the
JPLQZZPTHMPTYX is hardly a work
of art as it sits on my roof novadays.
But, like a tiny barn weather vale that
seems huge when you have it d)wn on
the ground for repairs, the ten element
antenna shrank remarkably whet we got
it up where it belonged. Now, hardly
even notice it. And when the E.g Wind
came, the thing just rocked a Sit fore
and aft, and stayed put.
And so to business. I cannot specifically say that this ten -element unit with
the log-periodic system incorporated is
the answer to your stereo dreams simply
because, rooftop conditions b,:ing what
they are, I was not able tit make a
direct A -B comparison with somebody
else's ten -element array, or' equivalent.
"
Just mount it on top of your traction
motor, suitably geared, and fasten the
whole thing to ground via a solid steel
and concrete pillar from the roof down
into your basement. (On second thought,
you'd better build the pillar first, then
put up the house around it.) Next, hire
a couple of cranes and raise up your
antenna to the top of the flagpole. Wow!
You're off in a cloud of stereo.
(I have a more modest alternative.
Buy yourself one of those huge Dutch
windmills, the largest, and have it
shipped over here, complete with the
big, sweeping sails. Then upend the
whole thing onto your roof with the
sails up, mount the antenna on them
and hitch up your traction motor. You're
in business.)
But to return to reality, you really
can't afford to bother about sutler -antennas, because the 10 -element full -wave
Please-my house! I'm not going up
there on the roof and ask for trouble
with two of these monsters! But there's
a better reason. See AUDIO for October,
p. 33, where Walter Wohleking shows
a picture of two antennas on a roof
getting in each other's hair. He notes
that this sort of antenna proximity "deteriorates pattern and impedance of P:
antenna" and I can back him up si
fically. At first, I thought I'd try
AUDIO
FEBRUARY, 196.
AP's
INC.
dirty laundry
the repair
This AR -2a
room
was bought in 1962. Three years later it developed
under the terms of our five-year guarantee.
a
buzz and was returned to us
fixed it, sent it through regular production test channels, and returned it to its owner in East
Hartford. We also sent him a check for $3.95 to reimburse him for his expenses in shipping the
We
speaker to us.
didn't cost him anything-we had even sent him a new shipping carton in which
to return his speaker. It did put him to a lot of trouble, and we're sorry about that. But we don't think
that the return rate of AR-2a's and AR-2a"'s (less than nine -tenths of one per cent over the five-year
The entire transaction
life of the guarantee) can be reduced much. It is already lower than the figures projected by many carton
manufacturers for shipping damage alone. AR speakers are packed in heavy, over -designed cartons, and
before being packed are subjected to testing and quality control procedures that border on the fanatical.
Reliability backed up by a complete guarantee is important, though certainly not enough reason to
choose a particular speaker. The advanced design and superior performance of AR speakers is
recognized almost universally. They have consistently been rated at the top by equipment reviews, and
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Check No. 68 on Reader Service Card.
AUDIO
FE
3RUARY, 1967
19
new antenna and the old togetherwhile the wind was calm-on the same
old mast, and I did. It didn't work. All
I got was a weird set of sensitivity lobes
that certainly did not represent either
the FM/Q or the JFD. Just as he said.
And so, down came the old model and
up went the new one, solo. I can only
speak, therefore, for what the one antenna has done for me since then. That's
plenty.
The JFD people claim that the log periodic configuration gives "up to 41
percent more signal voltage than today's
best 10 -element FM yagi," a statement
that I can't possibly substantiate, you
see. But I rather suspect that it does.
The thing is amazingly effective. It has
solved maybe 98 percent of my far fringe distance problems for me, stereo
and mono both. That's something I never
would have thought possible.
What IS the log -periodic array? Uhuh
gotta be careful. I'm the dumb amateur, remember. You'll find plenty of
good accounts in proper engineering language. I'll only say that the antenna,
with its side arms and reflectors, looks
outwardly much like the familiar sort;
but the arms are longer and graduated
in size (obviously in a logarithmic relationship) as you move from back to
front. And they are hooked up in an
ingenious fashion, alternating from side
to side, each transmission line connected
to a right, then a left, then a right arm
and so on.
There is an excellent account of this
type of antenna, if I may quote an esteemed colleague magazine, in the February 1966 issue of Electronics World,
though it concerns TV applications primarily. There, you may find specific
info on the mathematical relationships
involved in this ingenious species of array. I caught on easily enough; but I am
much too wise to start paraphrasing in
this department. All that need be said
here is that a single dipole, as we all
know, is ideally tuned for a single resonant frequency and not only does its
"radiation" (i.e., its sensitivity-doesn't
matter whether the signal is coming or
going) change with signal frequency but
also its impedance. So, short of dozens
of dipoles to bring in every channel,
we can ordinarily do no better than
compromise for wider, smoother sensitivity; and that is where the fun comes
in for the antenna designers.
Via the log -periodic dipole array,
which was developed in 1959 (it says)
by D. E. Isbell at the Antenna Laboratory of the U. of Illinois, a collection
of mated dipoles somehow manages to
act like one theoretical super -dipole with
a high and uniform sensitivity over a
very wide frequency range-theoretically,
as wide as you wish, given enough elements. (Am I right? I think so.) Since
this is precisely what we all want, the
-I
log -periodic just has to be good. That
is, if it works out in practice. It seems
to.
Karlson
I must say that I am strongly reminded of an old speaker problem that
is oddly related, that of smoothing out
speaker -cabinet resonance in the bass.
Remember the big arguments we used
to have, the assorted tunings, the blended peaks, cone resonances, cabinet resonances, reflex circuits, etcetc.? But do
you remember in particular one tricky
wide -band bass enclosure that always
has struck me as amazingly simple and
ingenious-the Karlson? Instead of
a
hole, behind, it loaded the speaker in
front with a spreading slot, a mathematically curved V, for an infinity of
resonances in the range of the bass
tones, smoothly blended over the necessary bandwidth. Strange, how much like
the log-periodic solution that Karlson
arrangement turns out to be.
Saturation Tuning
Now-for results. Not comparative
but absolute.
I've already noted some 61 fully limited mono stations, actually identified
as of last month's column. Since then,
of course, I've stumbled onto still more,
or have waited them out, none too
patiently, until the darned things could
get around to identifying themselves.
I've stayed up late (ugh), until 2:30
or 3 a.m., just to pick up a few chance
extras in the holes that open up around
midnight. (But the distant ones go off
the air too.) And so my total is now
around 70 -plus. And there are dozens
more, I suspect, if I could just get them
to tell me their make, model and location.
In fact, it is a novel experience, quite
new to me, to reach what amounts to
almost complete saturation in terms of
the spectrum of stations. During most
of my listening time, now, except for
a few hissy blank areas down among the
educational stations (below 92 me and
to the bottom at 88.1) there is not a
single empty space on the dial. The
tuner passes smoothly from one fully limited signal to another, straight from
one end of the non -educational segment
to the other, and not a hiss the whole
way. Sometimes a few "holes" at the
very top. Never in the middle, where
the main power stations are located. Talk
about inter -channel muting! I don't have
any interchannel to mute.
Now one of the supreme advantages
of FM, over the old familiar AM spectrum, is that when two signals meet,
the weaker one bows out, the stronger
one taking over completely. I suppose
this depends partly on the tuner circuit, but the principle holds for all FM
reception, as opposed to comparable AM.
My tuner -antenna combination, then, is
doing a very characteristic job here.
You see, I find, as I should indeed, that
I get very few really distant stations.
Instead, I simply get more stations,
within a rather specific circle of distance,
roughly 100 miles out. That is because,
in my Northeastern location, the vast
number of FM outlets within that 100 mile contour, especially in the greater
New York area, simply fill up all the
available space. The more distant outlets, on the same frequencies or between, never have a chance to appear.
They are the weaker signals. They are
totally suppressed.
Thus, given a proper "hole," I can
get any Philadelphia station, well over
200 miles away as I figure it, with entire
mono limiting and even with passible
stereo quality-a moderate hiss, not too
objectionable. But there is seldom a
crack for Philadelphia to get through,
past New York! Somebody nearer and
stronger is always monopolizing the
channel. And Philadelphia is directionally
too close to New York for my rotator
to help.
To my West there are endless mountains, wild country and a few really distant stations out in Pennsylvania and
Western New York State. Often they
are drowned by the weak side -pickup
of much nearer and stronger outlets to
the South. To the East, mountain trouble
keeps the distant stations away-but I
get Hartford, 50 miles out. (See below.)
Northwest, there's a pack of powerful
stations in the Albany -Troy -Schenectady
region, but beyond them only a thousand miles of wilderness, up into Canada.
No signals.
So-no spectacular distance -getting.
Not here in the crowded East, anyhow.
And no skip waves.
That's the whole idea. And I'm all
for it, much as I'd like to pick up, say,
San Antonio, or Charleston, S.C., and
boast to you. Do that on AM. Not FM.
The Government Was Right
In fact, I now see anew how abundantly right the government has been in its
careful allocation of the many FM channels. No doubt about it, the present
system works wonderfully well, in spite
of the many changes that have occurred
in FM since the present band was set
up after the war. With enormously more
sensitive tuners, more potent signals and,
today, more powerful antennas, the arrangement of stations is still an excellent
one and is not likely to suffer a bit, as
I see it, from further changes in equipment.
Just take a look at the aforementioned
Sams book, the North American RadioTV Guide, and see how the stations on
each channel are distributed all over the
country at calculated distances from each
AUDIO
20
www.americanradiohistory.com
FEBRUARY, 1967
"DON QUIXOTE" by Dali.
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sentiment, a quest and a yearning for more perfect existence.
Ultimate perfection in sound reproduction is the goal of every engineer and
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AUDIO
FEBRUARY, 1967
21
other, and how, moreover, those in each
big city seem generally to be staggered,
every other channel. That works, too.
A tuner like my big Scott 312 (as
mentioned last month, it is the test
machine for these articles) is precisely
adjusted to this situation. In the crowded
mid -spectrum, the every -other-channel
arrangement brings in each station over
a spread that completely overlaps the
intervening channel; there is not a trace
of interference. But in those cases where
strong stations do exist on adjacent channels but in different directions, the JFD
antenna separates them neatly and the
tuner brings in each one, cheek by jowl,
again with no interference whatsoever.
A specific example. One of my chief
listening stations in New York is
WQXR, at 96.3 mHz. Right next to it
is another important one for me, WTIC
in Hartford, Conn. at 96.5, the adjacent
channel. At 96.7 there is a strong local,
WSTC in Stamford, Conn., just a few
degrees off from New York and close
enough to me to be plenty potent. (50
miles, about.)
Now when the JFD is aimed at New
York City, SSW, I get the first and
third of these, which the government
has wisely spaced apart via one intervening channel, just as though they were
adjacent. WQXR at 96.3 gives way directly to WSTC at 96.7 with no trace
of overlap or interference. The station
in between, WTIC at 96.5, simply does
not exist, though it is a potent signal,
only some 50 miles away. That's because it's to the East; the others are
South -Southwest.
But swing the JFD antenna around
to East and WTIC comes in with top
signal strength on the meter, and the
other two stations vanish! WTIC is now
much stronger than either of them, and
so its signal blanks out the two channels
on either side. Excellent.
The system works even better than
that. Take two good, potent stations on
the same channel. Again, the government
has them geographically well separated,
so that the chances are good that if you
are 'way out in the fringe they will fall
into different directional locations for
your antenna. (If you are in close, you
get one station only. Period.) I'll give
you an example here, too.
In New York city there is a noncommercial outfit named WBAI, a branch
of the Pacifica group on the West Coast.
A zany station, yes, nutty at times, but
always interesting. People die for WBAI
hereabouts in Connecticut-but they die
in vain, so to speak. They can't get it.
Boy, do I get it, though, at 100 miles!
Like a local.
22
Now
WBAI, listener-sponsored and
all that, is located at 99.5 mHz. SSW
100 miles.
It happens that there's another station on the same 99.5, off to my Northwest at about the same distance. It's
far away from WBAI; but I'm right
between. WGFM, 99.5 in Schenectady
(General Electric, the FM outlet for
WGY) is NW 100 mi. And boy, do I
get that one, too! Full strength.
But not simultaneously. Each one is
clear as a bell, completely minus
interference. All I do is tune the Scott
to 99.5 and rotate the antenna. The
sharp line that separates these two strong
stations must be heard to be believed.
No fading, no flutter-they are too
strong for that. Instead, a hair's breadth
motion of the antenna and one is gone,
the other is there. It can't be more than
an inch or two, up on the roof. I find
it impossible to stop the rotator on the
as
exact point of turnover.
Not only that. There are signs of a
third station on 99.5, faintly, somewhere
else on another segment of turn, though
I haven't identified it. Could be off -tuned
on another channel, next door. You have
to work quite awhile to untangle such
mysteries.
But the fact is that this particular
combination of tuner and antenna, the
Scott 312 and the JFD etcetcetc., is
perfectly capable of bringing in at least
three strong stations on a single channel,
selectively and without interference, if
the directions and signal strengths happen to be rightly dispersed. Not too
likely in practice; but on many points
of your dial you will easily separate two
stations if you are in a typical fringe
area.
You will see in the North American
Guide that each FM channel is assigned
to from ten to as many as thirty or so
stations, spread out all over the country.
If you log your own area, you discover
that you are neatly confined to a calculated one station per channel in almost all cases, seldom more than two,
even allowing for time off the air, and
for directional differences. That is exactly the intention. And the beauty of
it is that the situation does not change
with a more powerful antenna. You
simply fill in more channels, at more
uniformly high signal levels; everything
within an area of a hundred to 150
miles (assuming a clear location) becomes "local." Not a trace of that terrible hash of mixed signals and static
that used to enliven the old AM days!
Old Major Armstrong knew what he was
doing when he invented FM. So did the
government when it set up the present
arrangement.
Just
a Thumb Print
Really distant stations on FM, then,
are virtually impossible to get except
maybe in the most sparcely populated
areas of the country, out in the deserts
and plains. A 250 -mile reach seems a
lot, as you tune it in with full limiting
and perfect in -the -room reception. But
look at the U.S.A. and see what a tiny
segment of the whole you cover! Just a
thumb print on a full page of map.
That's exactly as it should be. A bigger
antenna-even my super-windmill job or
the flagpole model-will make not a
particle of difference; you'll just get more
stations, stronger, and 99 percent of them
will be within that thumb print that has
you at its center. You can forget about
the vast stretches of territory that make
up all the rest of our great nation.
Quite a set-up, this FM!
Stereo
And what about stereo? I've said no
more because I've said it already. Stereo,
with its much weaker effective signal, is
locked into the same picture, in proportion. Along with my 70 -odd mono signals I've picked up a couple of dozen
stereo emanations in my thumb -print
area and virtually all of them are now
listenable, minus background hiss. That's
because there is signal strength to spare.
You see, the same saturation principle
applies to stereo. Once your bandwidth
is filled up with strong "local" stations,
up to 150 miles, there is no way for the
weaker stations to get through. You
don't hear them. Blanked out. And so
you seldom hear really weak stereo,
either. Like Philadelphia from my location. When it gets through on stereo,
occasionally, it's hissy. But mostly it
doesn't get through at all. Might as well
not exist.
Though the Northeast is maybe the
most crowded FM region, there are
surely similar situations out in the fringe
areas of the middle West and on the
West Coast, where with one of these
new FM antennas you will get the same
sort of channel saturation, and hence
the same strong stereo straight across
the dial. Very pleasant, you'll agree!
That's what I was after. I've got it. And
so the infamous FFFFF problem is
licked, at least for me.
P.S. If I had more space I'd tell you
about the curious reception patterns I
turned up with the JFD on my rotator,
the oddly useful spiky lobes here and
there, and, not less important, the trick
ways I found to identify recalcitrant stations that refuse to name themselves. I
could even measure distance by the reception characteristic, spotting a weak
nearby local from a distant signal in
no time flat. Maybe later for all this. Æ
AUDIO
FEBRUARY, 1967
The More Intricate The Musical Patterns Become,
The More You'll Appreciate Bozak
A Bozak speaker can reproduce a trumpet solo
with the utmost clarity. Any number of other
speakers can do as well.
But, when it comes to reproducing a major
symphony played by a major orchestra, Bozak
stands alone in its faithfulness of reproduction to
the original performance.
tail, instrument by instrument, and treble speakers
have the warm, sweet natural notes, not artificial
strident tones.
That's why we urge you to listen to all types of
music when comparing loudspeakers. If the speaker you choose isn't capable of reproducing all
types of music with maximum realism, you'll soon
tire of it.
Here's Why
Bozak speakers are engineered for the music
lover. Each component speaker reproduces its
portion of the audio spectrum in such a way as to
deliver not only the frequency, but the spirit of
music; it is this that sets Bozak apart from all
other speakers. Bass speakers deliver foundation
tones which give a sense of feel and of ease to
music; midrange speakers provide clarity and de-
Musical Test Track
Just as you wouldn't judge an automabile's performance on the basis of smooth, level roads, we
don't think you should judge your loudspeakers
on that basis, either.
We'll gladly suggest a couple of recordings
which contain most of the obstacles to realistic
reproduction
sort of musical "test track".
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AUDIO
23
FEBRUARY. 1967
www.americanradiohistory.com
EDITOR'S REVIEW
NEWS OF THE 1967 SHOWS
IMMEDIATE INTEREST, Of course, is the Washington High Fidelity Music Show which will
open at the Park Sheraton in Washington,
D.C., on Friday, February 10 and continue through
Sunday, February 12. The Washington and Philadelphia shows, run under the direction of Teresa Rogers,
have always been good ones, and we look forward to
seeing many of our regular readers again.
It has already been announced that there will be no
Spring show in Los Angeles this year, and none at all
in San Francisco. This was in accordance with the
wishes of the membership of the IHF, as expressed at
a general meeting held during the New York Show.
However, the Ambassador Hotel bungalows will be the
scene of the only California Show in 1967, and that
will be from October 25th through the 29th. As the
Ambassador cottages represent probably the best site
of all the cities where hi-fi shows have been held in
the U.S., we are most pleased with this development.
And, of course, the Fall dates are more acceptable to
the manufacturers and their representatives and dealers,
most of whom have deplored the March or April dates.
Some of us in the East preferred the even earlier February dates of several years ago, since it gave us an opportunity to get away from the snow during our worst
month. But it is undeniably better for the exhibitor,
and after all, what is good for the industry must be
good for us. So we'll be in L.A. in October.
As to the county's largest hi-fi show-New YorkSeptember 20 will see its opening in a new location.
The Statler-Hilton Hotel, directly opposite the Pennsylvania Station on Seventh Avenue in Manhattan, and
known for many years as the Pennsylvania Hotel, has
revamped its second and third floors to accommodate
shows of various types, and the IHF New York Show
moves there for a five-day stay. In many respects, the
solid walls of a hotel-and particularly one built the
way they were built in the "good old days"-will make
a much better setting for our industry's type of exhibit.
When the rooms are separated only by dry -wall partitions of perhaps a half -inch thickness, it may be true
that the spectators can not see what goes on in the next
one, but they certainly can hear, and it is next to impossible to evaluate the performance of the equipment
being demonstrated when the one in the adjacent exhibit room is only 10 dB down from the one we are
trying to assess.
As an exhibitor, we have always accepted the inevitable and made the best of the facilities, and since
our own exhibit has never depended on the sound we
create in our room, we really couldn't care less from a
selfish viewpoint. And while the Trade Show Building
OF
offered a haven when the previous location became
untenable because of difficulties in handling the crowds,
and while the mechanics of staging a show there were
as comfortable as one could want, there was still that
background of your neighbor's exhibit. We'll miss Tex
Carlton, who ran the Trade Show Building during our
many shows there, and will undoubtedly continue to
hold forth in the same place, but we expect the new
location to be a definite improvement. Time will tell.
In any case, remember the dates-though we'll remind
you from time to time anyhow-September 20th
through the 24th.
A REAL STEP FORWARD
Of far more importance than the shows-as far as
the entire industry is concerned-is the teaming up of
the IHF with the National Design Centers in New York
and Chicago to effect a co-operation between them in
the presentation of a permanent "Sound Ideas" exhibit.
The National Design Center, under the direction of
Norman Ginsberg, its president, will create nine separate decorator rooms, each with a different period of
design, but with a central theme of decorating with
sound. The basic idea is to demonstrate the use of
components to provide flexibility in the decor of livable
rooms.
Since these exhibits are essentially permanent, they
will be seen during the next twelve months by perhaps
half a million people who browse through the centers
to get ideas as to how they can improve their own
homes. New ideas in decorating materials are constantly on display in the two centers, and while the
visitor to one of them might not follow any given
design slavishly, he is certain to get at least one idea
every time he walks through them.
We believe this relationship between the Design Centers will do more for the component concept than hi-fi
shows ever could.
DECEMBER'S SHOWINGS
Two events occurring during December are worthy of
mention-Sony showed an AM radio that was almost
exactly the same size as one-third of a pack of king-size
cigarettes. In this miniscule device is an integrated
circuit which contains nine transistors and all their necessary related capacitors and resistors.
And a week earlier, Columbia Records hosted a delightful tour of their new headquarters in New York.
The facilities there are as complete as their requirements could possibly dictate-and if they are not adequate, we'd guess that there'd be some changes made
until they were. Quite a place.
AUDIO
24
www.americanradiohistory.com
FEBRUARY.
1967
For
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For
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tracing.
New Pickering V-15/3 cartridge with Dynamic Coupling for minimum tracing distortion and maximum tracking ability, plus Dustamatic'
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As stereo cartridges approach perfection, dust in the grooves becomes intolerable.
The Pickering V-1 5 / 3 Micro -Magnetic' cartridge has a new moving system that
reduces tracing distortion close to the theoretical minimum, thanks to Dynamic Coupling
of the stylus to the groove. But what good is perfect contact between the stylus tip and
those high -velocity turns if dust particles get in the way?
That is why the Dustamatic brush assembly is an essential part of Pickering's
total performance cartridge. It cleans the groove automatically before the stylus gets there.
The new moving system also provides a further refinement of Pickering's famous
natural sound by extending peak-free response well beyond the audible range, and the
patented V -Guard Floating Stylus continues to assure the ultimate in record protection.
There are four "application engineered" Pickering V-15/3 Dustamatic models
with Dynamic Coupling, to match every possible installation from conventional record
changers to ultrasophisticated low -mass transcription arms. Prices from $29.95 to $44.95.
For free literature complete with all details, write to Pickering & Co., Plainview,
L. I., New York.
'11
For those who can hear the difference.
Pickering
Check No. 70 on Reader Service Card.
AUDIO
FEBRUARY, 1967
25
Compare these new Sherwood S-8800 features and specs! ALL- SILICON reliability. Noise -threshold -gated automatic FM Stereo/mono switching, FM stereo
light, zero -center tuning meter, FM interchannel hush adjustment, Front -panel mono/stereo switch and stereo headphone jack, Rocker -action switches for
tape monitor, noise filter, main and remote speakers disconnect. Music power 140 watts (4 ohms) ® 0.6% harm distortion. IM distortion 0.1% 13 10 watts or
less. Power bandwidth 12-35,000 cps. Phono sens. 1.8 mv. Hum and noise (phono) -70 db. FM sens. (IHF) 1.6µy for 30 db quieting. FM signal-to-noise: 70 db.
Capture ratio: 2.2 db. Drift x.01%. 42 Silicon transistors plus 14 Silicon diodes and rectifiers. Size: 16;4 x 434 x14 in. deep.
!WE
HAVE COME TO EXPECT HIGH PERFORMANCE
FROM SHERWOOD and...
the S-8800 did not let us down. The tuner
section, with its high sensitivity and very
low distortion, is among the best in the business-clean and responsive. FM Stereo comes
in Ioud and clear and, as the curves plotted
at CBS Labs show, with very ample separation. The usual increase in distortion, when
switching from mono to stereo in receivers,
was in this set just about negligible. We would
say that Sherwood has come up here with another typically 'hot' front end that makes FM
listening a sheer joy.
"As for the amplifier
comparing the results with the specifications, it is apparent
that the S-8800 does provide the power it
claims, and this-for a popularly priced combination set-is considerable. A glance at the
IM curves, for instance, shows how much
power the S-8800 will furnish before it runs
into any serious distortion problem at all
three impedences.... For rated power bandwidth distortion of 1%, the curve ran below
and above the normal 20 to 20 kHz band; and
the 1 -watt frequency response was virtually
a straight line in this area, being down by
2.5db at 40 kHz-fine figures for a receiver...
'Those heavy percussion and crisp castanets
will come through with just about all the
con brio the performers have put into them.
...
f
I60XM5
4 OHMS
1
BOWS
IM CHARACTERISTICS
4
I
7
30
O
40
O
TO
100
POWER OUTPUT (WATTS)
*As appeared in HIGH FIDELITY Magazine Equipment Reports
by CBS Labs. November 1966 issue.
S-8800 140 -watt FM ALL -SILICON Receiver
$359.50 for custom mounting
$368.50 in walnut leatherette case
$387.50 in hand -rubbed walnut cabinet
it
fN(tWODU
91...
9h
98
l00
3
102
99
-YEAR WARRANTY
StttCON
104 166 .10811IC
U
F
3
C.]
Sherwood ,Electronic Laboratories, Inc., 4300 North California Avenue, Chicago, Illinois 60618. Write Dept. 2A
Check No. 72 on Reader Service Card.
26
AUDIO
FEBRUARY, 1967
Professional
'Pone
Controls
In Three Parts
-
Part
1
So you want to become an audio engineer. Here, in three parts, are some
of the important considerations which must be included in any planning
of a professional installation. In fact, the principles presented may well
be thought of as the groundwork of any professional -system philosophy.
ARTHUR C. DAVIS and DON DAVIS
THE PROFESSIONAL AUDIO ENGINEER has long used fixed -gain
passive-control components in recording, broadcasting, and reinforcement system design.
Increasingly, the audio experimenter
and high -quality -audio buff is becoming aware of the differences between
home high fidelity components and
those used by the professional engineer.
Three major differences are obvious
when professional audio systems are
compared with the very best home
hi-fi systems. Professional systems
utilize:
1.
Fixed gain amplifiers.
2. Passive control devices.
3. Low impedance transmission
circuits.
Not so immediately apparent are
the factors of greater precision, longer
service life, and greater versatility of
service inherent in the professional
components.
There are two types of controls
possible in audio systems:
1.
Active circuits.
2. Passive circuits.
Active Circuits
Active circuits are those that exert
the required control by means of varying changes in the feedback circuit
of an amplifier. Usually such controls
AUDIO
FEBRUARY. 1967
are basically some form of frequency discriminating network in the feedback
loop of a negative -feedback amplifier
which shapes the gain -frequency characteristics of the total amplifier.
Passive Circuits
This article is a short general discussion of the passive controls used
in professional audio systems and
shows how the advanced high fidelity
buff can graduate to a fixed -gain, passive -gain, passive -control, professional
sound system.
Passive controls are those that exert
the desired change without power
being added in the process. Passive
devices take the form of:
1. Atrenuators. Normally a resistive
network that attenuates equally at all
frequencies within the bandpass of
interest while maintaining constant terminal impedances.
2. Equalizers. Devices that attenuate or restore inserted attenuation at
selected frequencies.
3. Filters. Filters and special effects
devices under this category are high and low-pass filters and notch filters.
These devices are characterized by
zero insertion loss at all frequencies
other than their operating frequencies.
Passive Equalizers and Filters
Passive equalizers and filters can
be of the RC, LC, or RLC type. They
can be constant "K," "M" derived,
Butterworth, or Chebishev design. The
circuits employed can be:
Both of these circuits
are characterized by
input and output impedances that change
with frequency.
These circuits maintain a constant input
Full series
impedance but the
Full shunt
output impedance varies with frequency.
These three circuits
"T"
are identified by conBridged "T" stant input and output
Lattice type impedances.
Series
2. Shunt
1.
3.
4.
5.
6.
7.
Equalizers and filters can further
he of the balanced or unbalanced circuit configuration. Because of the 2 to -1 cost consideration and the very
short length transmission paths inside
a professional audio console, most
equalizers and filters are of the unbalanced type. Any transmission circuits that enter or leave the console,
however, are balanced and isolated
from the unbalanced console circuitry
by the use of high -quality repeat coils
(isolation transformers)
.
27
Circuits Used Commercially
The devices discussed in this article
are all of the four -terminal constant -K,
unbalanced -circuit, passive, bridged -1type. The preferred impedance is 600
ohms, though 150 ohms as well as
other values are encountered in the,
use of such devices.
126
100
" -- _
100
----_
----
FUNDAMENTAL
__
Advantages of Passive Controls
The advantages of using such a
passive control can be summarized as
follows:
1. Very low design cost compared
to a really stable active circuit.
2. Less complicated to build and
DO
s
a6
01
20
HARM HIC
O22
023
w
IE
FREQUENCY IN HERTZ
distortion of a circuit with
the frequency response of Fig. 2.
Fig. 1. True
to use.
Precautions to Observe
It is possible in the design of active
circuits to "magnify" the "Q" of an
inductance used, thereby allowing
smaller sized components to be employed. When passive devices are used,
particularly at low frequencies, size
and weight of the components required will not lend themselves to
miniaturization. Due to the high "Q"
coils employed in passive equalizers
care should be exercised when they
are employed near appreciably high
.
0
3. More reliable over long time intervals. Greater repeatible accuracy.
4. More versatile. It can be used
in system after system because it is
an independent component.
5. Extremely low maintenance costs.
6. Minimum distortion that remains
constant. No circuit changes in amplifiers will change the inherently low
distortion figure of the controls. (Not
measurable.)
flux fields.
5
10
9
15
24.5
20
25
30
f
35
40
2f
1631 dB
dB
31 dB
d6
J31
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4f
la
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,
am
FREQUENCY IN HERTZ
looQQ
100°°
Effect of
2.
Fig.
frequency response on measured distortion
figures.
70
dB BELOW FUNDAMENTAL EXPRESSED AS A PERCENTAGE
60
VOLTAGE -CURRENT
50
40,
t....
30
Chart showing percentage derived from measurement of distortion as the number
of dB below the
Fig. 3.
,,.,.
20
,...,
10
0
0.01%
2
4
fundamental.
1007.
10%
1%
FREQUENCY IN HERTZ
0 15.
120
120
t/' `
,
110
1d0
100
9D
BO
m
r
i106AFUNDAME
B
100> FUNDAMENTAL
[
T
)0
, M
s
60
50
i
O.
40
1
HARMONIC
01
30
017. HARMONIC
II
HARMONIC
20
HARMONIC -
100
O.
Wd
,m
FREQUENCY IN HERTZ
harmonics
flat -response system.
Fig. 4. Distribution of
28
Distortion Measurements
Pose Special Problem
Finally, it should be recognized that
any frequency -response curve with a
changing amplitude
characteristic
makes distortion measurements difficult. A typical example is the measurement of distortion in a crossovernetwork where the technician begins
at a frequency that is on the slope
of the network's response. Let's say
that the real distortion characteristic
looks like the chart shown in Fig. 1.
Figure 2 discloses the slope of a 12 dB -per-octave crossover network. If
100 Hz is chosen as the measuring
frequency, then it can be seen that
the second harmonic will be increased
12 dB due to the slope. From Fig. 3
it is obvious that a harmonic 60 dB
below the fundamental represents 0.1
per cent distortion, but, due to the
slope of the network, the 2nd harmonic is now 60 dB minus 12 dB
below the fundamental or 48 dB below the fundamental which equals 0.4
per cent distortion. The 3rd harmonic was 74 dB below the fundamental or 0.02 per cent distortion.
Now, because of the slope of the network's frequency response it is now
74 dB minus 24.5 dB below the fundamental, or 49.5 dB below the fundamental, and this equals a distortion
indication of 0.32 per cent.
in a
FREQUENCY
HM TZ
INHTZ
Fig. 5. Distribution of
system with
a
m
harmonics
...
in a
"boosted" response.
Measuring Distortion in
Equalized Circuits
This same discrepancy can occur in
the use of high frequency equalization. Figure 4 illustrates the distortion
characteristics of a system at a "flat"
setting, while Fig. 5 shows the apparent increase in distortion caused
AUDIO
FEBRUARY, 1967
by a high frequency boost of 12 dB
at 3000 Hz. (Notice that the 100 per
after effect. The unequalized portion
of the bandpass remains at a constant
cent indication for the fundamental
is also raised by the equalization process.) So far as the ear is concerned
such boost sounds like a real increase
in distortion and this effect puts a
practical limit on high -frequency
boost of about 12 dB.
Low -frequency boost can have the
inverse effect by dropping the higher
harmonics still lower in relation to the
fundamental .(This may well be the
reason low -quality package hi fi's are
usually adjusted "bass" heavy by their
users.)
level.
Calculation of Correction Factor
To obtain an accurate harmonic
distortion figure from a system with
a rising high -frequency amplitude
characteristic, take the measured distortion expressed in dB below the fundamental and add the dB increase due
to the slope of the system. This total,
converted to percentage, will equal the
true distortion of the system. (dB
measured distortion + dB scope increase = dB helow fundamental.)
Other Considerations
Attention must be paid to the insertion loss of the device (equalizer)
and the maximum and minimum levels
required for satisfactory operation. In
passive equalizers there are two
choices that can be made regarding
insertion loss. Because it is a passive
device the only way to obtain "boost"
is to attenuate all but the desired
"boost" frequency. When this is done
the "boost" frequency is higher, relatively, than the non -"boosted" frequencies. However, if we merely depressed the frequencies to be attenuated in, order to "boost" the selected
frequency, we would have a loss in
level at all frequencies attenuated that
would vary with each equalizer setting.
One way to achieve constant gain
in the equalizer is to use an inverse
loss attenuator in conjunction with the
equalizer. The attenuator inserts loss
at the "flat" setting and gradually removes it to the same degree that the
majority of the bandpass is depressed
to obtain equalization.
maximum allowable input signal must
not exceed -18 dB and -24 dB
respectively.
With these figures in mind it can
be seen that the maximum input signal
into an equalizer placed just ahead of
such an amplifier must not exceed
-16 dB. (-16 dB)-(14 dB insertion loss) + (12 dB max. equalization) = -18 dB output at some selected frequency. If for one of a number of reasons the output from the
equalizer exceeds this figure the use
of a fixed loss pad can correct the
Dynamic Range Determined
Passive equalizers and filters of the
unbalanced, bridged -T, constant -K type
illustrated in this article should be operated between the levels of -70 and
+20 dBm. Figure 6 reveals the dynamic range, noise, and gain characteristics of a high -quality, fixed- gain,
plug -in -type professional audio system amplifier. This same amplifier
shown in Fig. 7 can be used as a
preamplifier, booster, program, and
even line amplifier by merely changing the "strapping" at its external
socket connection. This allows a single
type plug-in unit to be used interchangably anywhere in the system and
this minimizes the number of units
required for maintenance back-up.
Fixed -gain amplifiers of this type can
be designed for optimum negative
feedback and stability. Figure 6 shows
that the maximum output for the unit
per cent THD 20 to
(at less than
20,000 Hz) is +27 dBm. Since it has
a fixed voltage gain of 45 dB terminated and 51 dB unterminated, the
level.
Fixed Parameters
Again referring to Fig. 6 the fixed
parameters are seen to be maximum
output level, maximum input signal
level and the equivalent -input -noise
figure (E.I.N.) and consequently, the
maximum signal-to-noise ratio. The
dynamic range and the minimum signal-to-noise ratio are parameters that
are played against each other depending on the requirements at hand. In
general the minimum signal-to-noise
ratio need not exceed 10 dB with 25
to 30 exceptionally quiet. The maximum dynamic range available in a
,
1
+50
-
r__t_
-r
+30
+10
10
30
GAIN
»,
r
70
90
I
110
MIN. S/N 45 dB
1
-130
20
100
r
S/N
r r » IMrr»
109 dB
1
Mr
7
-18 MAX. SIGNAL LEVEL
DYNAMIC RANGE
64 dB
MAX
50
I
dBm MAX OUTPUT
MIL
r rrr
45 d3
1
;
+27
r
_82 MIN.SIGNAL LEVEL
1t.7r
rr---erET.
X127
d
E
TBm
000
I
N.
10000]0000
FREQUENCY IN HERTZ
Fig. 6. Relation of
dynamic
noise,
-
and
range,
gain
characteristics of
high -quality
a
fixed -gain professional amplifier.
Preferred Method
In the equalizers to be discussed in
this article a full bandpass insertion
loss is chosen, usually 14 to 16 dB,
and equalization restores the required
amount of this loss to obtain selective
boost at chosen frequencies. By this
means the only level change encountered in the program material is that
occasioned by "boosting" a selected
frequency. The resulting increased
level at that frequency is the soughtAUDIO
FEBRUARY, 1967
Fig. 7.
Amplifier of the type giving the
characteristics of Fig. 6.
29
very quiet studio is shown in Fig. 8.
The noise level shown is Noise Criterion Curve NC -20, and the maximum level shown is the maximum
sound power level (SPL) in dB at
120
110
t
«. r.. 0 Rms,m
4 feet that can be expected from the
best monitor speaker available. Since
the figure shown, 93 dB, is the maximum dynamic range, it is also the
maximum signal-to-noise ratio. Be -
114 dB-SPL
mr OR.ow, R10Or110011 01
0 III iEDOg
r
loo
90
80
70
J
93 dB DYNAMIC RANGE
60
`
50
40
NC
30
20
`..
20
lo
0
.1
100
10000
000
20000
FREQUENCY IN HERTZ
'Q
°
yD
''r 'R'
üüüüiii7ürIi
MIMI IlafflIIIIuall
'
MUM
1.11111111
1...
- Ic:
-.1 111I
a
=MC=MC=MCQIZYCi,
5011
.11111111
a' MAx.
0
MUM
*y
iGififiliiilailhil An.
=3. -iiii:CIifziiiJ.I.i
=pp111111111111111
MNOENSa d0
-`30
Fig. 8. Maximum dynamic range available in a quiet studio. The noise level
shown in the Noise Criterion Curve
NC -20.
80 a0S/H
,QI111
90
3-1N.SGNI
98E
MN
Fg. 9. Characteristics of a typical 20 watt professional-type monitor amplifier
Altec 9471A, shown in Fig. 10.
ii11M111111iin1111 Z
FREQUENCYIN HERTZ
1
Fig. 10. The Altec
20
947-A
-
watt
monitor amplifier.
i.
1" THD
TH
DVERCUT
LORI
30
-E..
1zá1
9.
ó_E.ß
60
]0
RECORDING
CONSOLE
ii
OVERCUT
i--i-.
i Mfi
IIMI
re
20
cause the ear can barely hear sound
below NC -20 any sound system with
a maximum signal-to-noise ratio of
better than 90 dB is going to have
a noise level below that found in even
the quietest acoustical environments.
The component that usually determines the noise threshold of the electronic part of the system is the power
amplifier. Figure 9 gives the gain,
maximum signal level, and maximum
signal-to-noise ratios for the 20 -watt
professional monitor amplifier shown
in Fig. 10.
Ó
x s_
MASTER TAPE
RECORDER
_
NA TER
DISC CUTTER
PRDDucnoN
PRESSINGS
90
nn
Fig. 11. Characteristics specified by a
major recording company for various
elements of their recording channels.
Fig.
12.
Peak power per octave in a
typical orchestral composition.
Practical Limits to Dynamic Range
Figure 11 shows the dynamic range,
and maximum and minimum signalto-noise ratios required by a major
recording company for their recording
consoles, master tape recorders, master disc lathe, and finally, their production pressings. In the final analysis, the real determination of realistic
dynamic range requirements and signal-to-noise specifications is the limits
set by the source material. Even the
finest professional tape recorder has
a maximum signal-to-noise ratio that
is 10 dB less than that achieved in
the 20 -watt amplifier shown in Fig. 10.
Another limitation of dynamic range
in a listening system is the occasional
use of a small "bookshelf" type speaker system with a mass loaded cone
to help lower cone resonance in a
too-small enclosure. Such loudspeakers exhibit a minimum level below
which the inertia of the cone and the
resistance of the suspension are not
overcome by the signal. Once the
input signal reaches a level of sufficient magnitude to overcome the friction and inertia, the loudspeaker suddenly "comes on." The transition from
low-level output to no output is not
continuous but is characterized by the
loudspeaker "shutting off" below a
critical level. The solution, of course,
is replacement by a more efficient
type of loudspeaker utilizing a lighter
moving system.
Energy Distribution of "Live" Source
One final consideration of dynamic
range and equalization is that of the
distribution of energy in typical source
material. Figure 12 exhibits the peak
power expressed in watts vs. frequency
of a typical orchestral composition.
It can easily be seen that consideration of equalization in the region of
125 Hz to 500 Hz requires careful
consideration of maximum allowable
input signal to the amplifier that follows such equalization. (For best results each program source should be
individually studied to determine frequency distribution of energy.)
Æ
(Continued next month)
AUDIO
30
www.americanradiohistory.com
FEBRUARY, 1967
Good
records start with Stanton.
A professional needs to know
for sure. When he listens to a test
pressing, he needs a cartridge that
will reproduce exactly what has
been cut into the grooves. No
more, no less. Otherwise he would
never be able to control the final
product. The record you buy in
the store.
That's why the professionals
keep using Stanton. It tells them
the whole truth, and nothing but.
In the photograph above, studio
engineers are- shown listening to
test pressing. This is a critical
stage in record making. The
stereo playback system they are
a
listening through is fronted
by a Stanton 581 EL Calibration
Standard. (The turntable also
happens to be a Stanton. Other
fine turntables will work, too.)
They're getting the whole message. You'll get it, too, in an upcoming release.
Each Stanton Micro FLUX
VALVE® Calibration Standard
is custom made. That means that
-
each will perform exactly as the
original laboratory prototype. We
laboriously adjust them until they
do. It also means that you will
get the same accuracy that the
professionals get. Guaranteed.
Stanton Calibration Standards
are hard to make. And the price
reflects it. $49.50. But
that really isn't much
to pay for uncompromising accuracy.
Stanton Magnetics, Inc.
STaNI'Of Plainview, L. 1., N. Y.
Check No. 73 on Reader Service Card.
AUDIO
FEBRUARY, 1967
31
sound ='ght
s.eeeeeSeeeeee
el
fi
HAROLD D. WEILER
Video tape recording will become education's fourth "R"-along with reading and arithmetic, predicted Leo M.
Storey, Jr.-marketing manager of General Electric's Closed Circuit Television
Business section. This prediction was
made at the recent introduction of GE's
new low-cost video recording system for
the educational market. Storey added,
that he expects VTR systems to quickly
become an integral part of modern educational and training programs.
General Electric's decision to market a
VTR system specifically designed for
the educational and training fields was
based on the vast unfilled needs of these
customers. Storey explained, "These
markets cannot always afford, nor do
they always require expensive complex
equipment. Research and analysis of
their special requirements led to the
development of our new system which
offers optimum performance at a reasonable price."
The uses for video tape recorders in
the classroom, on athletic fields, and
at any educational level from kindergarten through college are unlimited. Instantaneous sight and sound recording,
which can be replayed immediately without the costly processing or the time
lapse required with chemical film provides an effective and inexpensive method
for assuring comprehension of educational and extra -curricular assignments.
Storey added that the cost of one
hour of tape is approximately one-half
the cost of film. On economics, he
added that to produce a 30 minute training film the cost ranges between $40,000
and $80,000, and requires the services
of a highly skilled professional. "Anyone who can aim a camera can operate
our new VTR system."
The instant replay technique permits
students to review difficult areas of learning at their own pace and convenience.
Students who find it increasingly hard
to grasp lessons and keep up with the
class can now review those areas until
they are fully understood.
Teachers may now tape lessons which
can be replayed for students who miss
for future use or be circulated among
other schools and classes on a recurring
exchange basis. TV network documentaries of historical or general interest,
which are usually broadcast at inconvenient viewing times, for educational
purposes, may now be stored for delayed and more convenient replay during
school hours.
In the gymnasium or on the athletic
field, video tape recording can be employed as a valuable coaching aid to
visually demonstrate new techniques and
correct flaws. Football plays, for example
may be recorded and played back immediately to point out mistakes in passing, blocking and running and improve
both the team as a whole and individual
performances. Athletic instructors can
now use video recording as an electronic
aid to help improve batting styles, golf
swings, and swimming strokes.
Video recording can easily be applied
to speech and music training, drama,
driver education and science labs. In the
laboratory the combination of the video
camera -recorder and modified optical
Fig.
1.
equipment such as a microscope similar
to those normally employed, provides
the most powerful teaching aid in the
history of the life sciences. The GE system can serve as an electronic enlarger
which permits every student in the class
to observe every minute detail of any
demonstration or experiment simultaneously. All students can enjoy the same
image quality, eliminating the necessity
for individual instruments and viewing.
The observation of the greatly magnified
specimens is completely controlled by
the instructor, assuring that all students
are viewing the intended subject at the
proper time. Because of the video recorder more elaborate demonstrations
can be provided, since these recordings
may be used many times.
The new GE system housed in a
walnut grained Textolite® console, only
36 in. wide by 341/2 in. high and 183/4
in. deep is literally a miniature television recording studio. The top of the
console is divided into two sections which
house the video tape recorder and a
monitor receiver. Each section has an
General
Electric's new
video tape recorder mobile console
encloses the system's three major
components
a
video tape recorder, a monitor and
-
a
closed-circuit
TV camera, plus
a
complete set of
accessories such
as a tripod, microphone with lavalier
and stand, t/2 hour
of recording tape
and connecting
cable.
a class because of illness. Special lessons or lectures by experts, in a particular branch of learning may be stored
32
Check No. 74 on Reader Service Card
-
When you've got a reputation as a leader in transistor
technology, you don't introduce a transistor amplifier
that is like someone else's. We
didn't. The new Sony TA -1120
integrated stereo amplifier is the
case in point. We considered the
few remaining shortcomings that
have kept today's transistor amplifiers from achieving the quality of
performance of the best tube amplifiers and set out to solve them. To do it,
we even had to invent new types of
transistors. The result: the first truly great
solid-state stereo amplifier.
Distortion is lower than in the finest tube
amplifiers at all frequencies and power levels.
Signal-to-noise ratio: better than 110 db.
Damping factor is extraordinarily high (140 at
16 ohms). Frequency response: practically flat
from 10 to 100,000 HZ (+0 db/ -1 db). Plenty of
power, too (120 watts I1
-F at 8 ohms, both channels).
With an amplifier as good as this, the preamp
section has a great deal to live up to. It does, magnificently! Solid-state silicon circuitry throughout
coupled with an ingenious design achieve the lowest
possible distortion. Sensible arrangement of front panel
controls offers the greatest versatility and ease of operation with any program source.
Finally, to protect your investment in this superb
instrument, an advanced SCR (silicon-controlled rectifier)
circuit prevents possible damage to the power transistors
due to accidental shorting of the outputs.
The Sony TA -1120 stereo amplifier/preamp at $399.50 and
the TA-3120 stereo power amplifier, $249.50 are available at a
select group of high fidelity specialists who love and cherish
them. And will get as much enjoyment out of demonstrating them
as you will from their performance. So visit your dedicated Sony
high fidelity dealer and enjoy. Prices suggested list. Sony Corporation of America Dept. H 47-47 Van Dam St. L.I.C., N.Y. 11101.
With so many fine amplifiers
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www.americanradiohistory.com
quality performance, dependability and economical operation. The
slant -track helical -scan tape drive is very
simply and cleverly accomplished by having the video recording heads rotate on
a horizontal plane and guiding the recording tape around the scanning drum,
past the rotating heads, at an angle. This
provides
Fig. 3. The new General Electric type
TE -23 CCTV camera is solid-state, and
equipped with a crystal oscillator to
picture stability.
provide optimum
Camera resolution is approximately 500
lines when displayed on a standard
video monitor. Only two controls-an
on/off switch and focus knob-provide
simplicity and ease of operation.
individual lid with an adjustable support
to hold it in upright position or permit
it to be folded behind the console. Both
sections are equipped with key locks as
is the full length compartmented accessory storage drawer below to eliminate unauthorized operation. The console is mounted on cast aluminum legs
equipped with shock -absorbing casters
for easy manuverahility.
The solid-state video recorder employed. was designed to provide the ultimate in simplicity of operation. The tape
is threaded into the recorder and it is
turned on. When the record button is
pushed the recording begins. Even untrained personnel can create excellent
recordings since the recorder is equipped
with an easy -to -read recording-level indicator. Both video and audio levels
can be accurately set with the indicator
showing the optimum level for each.
This video tape recorder employs a
slant -track helical -scan tape drive which
angle is provided by the mechanical arrangement of the tape path. The tape
supply reel is mounted approximately
1 -in. higher than the takeup reel. Thus
the tape passes around the scanning
drum at a downward angle. With the
video heads rotating on a horizontal
plane and the tape passing this horizontal
plane at a downward angle the track is
recorded, on the tape, at an angle, as
may be seen. The helical -scan method
of recording permits the slanted video
tracks to be placed very close together
and in effect greatly increases the recording time which may be obtained with
a given amount of tape, reducing the
operating cost per minute. The economical tape speed of 71/2 i.p.s. further reduces the operating cost, however the
actual scanning speed of approximately
480 i.p.s. which is due to the combined
speed of the rotating heads and the
moving tape, in combination with the
sophisticated electronic techniques, normally employed only in more expensive
professional video recorders, provide a
horizontal resolution in
excess
of 200
more than adequate for the majority of educational applications.
The 12 in. monitor -receiver, expressly
designed for this system, is mounted at
the right side of the console. It may be
operated in the storage position, tilted
out of the console at a 30 degree angle,
or fully raised to the upright position.
While upright it may be swiveled 360
degrees to provide viewing from any
point around the console. When a video
camera is employed for recording, the
monitor displays the images being recorded to permit accurate camera placement, framing of the subject, and precise
recorder adjustment. When an off -the -air
program is recorded the monitor displays the signals being fed into the
recorder. When a video recording is
played hack the monitor displays the
images previously recorded. The monitor
may also be employed as a standard
television receiver for both VHF and
UHF reception. It includes provision for
connection to any existing school antenna system. A BNC coaxial connector
at the rear of the monitor permits
auxiliary monitors to be employed for
multiple display purposes.
The new GE TE 23 closed-circuit
television camera, illustrated in Fig. 3,
which is part of the system is also completely solid-state for reliable, trouble free operation. This compact camera is
fully automatic-anyone can operate it.
An ultra -fast f.1.4 lens, usually only
provided with high -quality professional
equipment, and the automatic sensitivity
control provide excellent images at extremely low light levels.
All of the camera's electronic components are contained on a single precision -etched Fiberglas circuit board.
This board and the camera's vidicon
tube are housed in a lightweight aluminum case. The camera, in the video
mode of operation, provides a horizontal
resolution of 500 lines. (300 lines at
the corners.). In the RF mode of operation the resolution is 300 lines.
The complete video recording system,
including microphone, lens, camera.
tripod, a 7 -in reel of recording tape.
and a maintenance kit is priced under
$2000.00. A similar unit in portable form
is available at less than $1700.00.
FE
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AUDIO
HOLDS
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ISSUES
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The valuable information in this publication will continue to serve you,
month after month, year after
when you file each issue in this
to -use, stiff-cover binder. Keep
copies safe from damage, safe
TAPE FROM SUPPLY REEL
TAPE TO TAKEUP REEL
HORIZONTAL HEAD ROTATING PLANE
SCANNING DRUM
Fig. 2. The helican
scan method of
video
used
TAPE
34
recording
in the
VTR.
GE
dust and
available.
it simple
holds 12
finished in
year,
easy -
your
from
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Binding mechanism makes
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lication title stamped in gold. Check
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Order from AUDIO
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AUDIO
FEBRUARY, 1967
1. Your choice: AC or DC, Cardioid or Omnidirectional-
Order the system you need now and expand by adding the
appropriate extra mike or supply at any later time. Get any
combination by simply switching microphones and/or power
supplies. Model designations: M49-AC/cardioid; M50-
Ten reasons why
Altec shouldn't sell
its new condenser
microphone systems
for $19800...
DC/cardioid; M51-AC/omnidirectional; M52-DC/omnidirectional.
Frequency response from 20 to 20,000 Hz-This is with
flat curve. Output level is -53 dBm re 10
dynes/cm2, with balanced system output.
2.
an essentially
3.
Extremely small diaphragm-Under 0.5" in diameter. HF
dropoff for sound waves arriving at random, non -perpendicular angles of incidence will occur only at frequencies above
20,000 Hz. All Altec condenser microphones contain diaphragms small enough to insure that HF dropoff does not
occur within the usable frequency range.
4.
100% solid-state circuitry-The 195A base utilizes an
FET as an emitter follower and also contains a 3 -pin XLR-12
connector. No RF or balanced -bridge critical adjustments
are used. The FET drops the extremely high impedance of
the microphone to an impedance suitable for connection to
a shielded 2 -conductor standard cable. Power is simplexed
over this same cable. The separate power supply provides
balanced outputs for standard 150/250 -ohm microphone pre amp inputs.
5.
Small, light power supply-About the size of two backto-back packs of cigarettes, both the DC and the AC supplies
provide ruggedness for long-term heavy duty combined with
small size and light weight for new ease in handling. Finish
is hard chrome.
6.
Long -life DC battery operation-Two mercury batteries
provide 2500 operational hours, up to a year in normal use.
A convenient meter on the supply shows battery condition.
Battery drain is prevented when system is not in use by
unplugging the 195A base or by operating a recessed switch
on the supply housing.
7.
Many accessories are standard-With each system a
wind/pop screen; microphone holder; and a 25 -foot, 2 -wire,
shielded cable are provided at no additional cost. Connectors
and mounting hardware are attached.
8.
-
The systems
High -temperature ambient permissible
will operate in an ambient up to 55° maximum (131°F).
9. Exclusive Altec
exchange policy-After expiration of
the normal full year guarantee, Altec will accept an
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policy is unique in the industry.
10. Microphone
is unusually small and
and base
light-This feature-microphone
are
31/2" L x
*
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importer profits to pay. Another part is that we know how
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AUDIO
FEBRUARY. 1967
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Send your inquiry today for
complete technical information.
We'll include a recent article on
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Alex Badmaieff, our chief engineer of transducers. Also our
colorful new 1967 Stereo Components Catalog, just in case
you're interested.
Check No. 75 on Reader Service Card.
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ALTE[
A Division of Lc`>7M Ling Altec, Inc.,
Anaheim, California
35
Audio Measurements Course
Part 13
NORMAN H. CROWHURST
THIS INSTALLMENT we shall continue discussing what have been
called "subjective measurements"
in audio. I feel that the word "measurement" in this connection is somewhat of a misnomer. I prefer the
word "test," but our psychologist
friends will probably give me an argument, by asserting that the results of
properly designed tests involving subjective judgment can be just as precise
and repeatable as any objective test.
Probably my deep-seated objection
arises from the question of what constitutes a "properly designed" test. The
number of facts or elements involved
is such that it is impossible to be sure
IN
that only the quantities nominally being compared are in fact the only ones
influencing the ultimate result.
In the last installment, we introduced the question of frequency band,
a factor that can be measured with
objective meters, with suggestions as
to how variations in the roll -off rate
could alter the conclusions about what
at first seemed such a simple comparison to make. How sharply frequencies beyond the band are removed
changes the subjective impression in
ways other than simple frequency loss,
about which it is difficult to obtain
meaningful distinctions from the subjects of the test.
*
*
*
(A)
*
*
*
i,
*
*
*
*
(B)
In each case the marks indicate where 10
different subjects identified location of a particular instrument from its stereo reproduction. At (A) location is quite accurate: the subjects agree closely on the location. At (B) location is scattered, indicating that sense of location is not strong.
Fig. 13-1. Types of subjective result.
It is difficult for a trained listener
to be certain why things sound different at times, so it is impossible to expect untrained listeners to give an
opinion, unless tests can be devised
that remove the conclusion from the
realm of opinion, into simple 'yes' or
`no' responses.
Stereo Illusion
As I suggested in the last installment, similar frequency-range tests on
two channels can relate the reality of
the stereo illusion or the apparent separation to the frequency band present in each channel. Tests to determine this usually take the form of
deliberately deteriorating either the
frequency response of each channel,
or the separation between channels
and asking observers to indicate the
apparent locations of different instruments in an ensemble of program material.
Such an approach is a psychologist's
dream. On the accuracy with which
subjects indicate the location and on
the consistency with which they identify it, quite positive conclusions are
possible. If the system gives a "tight"
correlation of position (with the particular program material presented,
which can vary too) then the observers will mark their charts quite consistently. If the correlation is not so
good, then the charts will be more
erratically marked (Fig. 13-1).
Such tests are repeatable, as the
psychologists claim, provided everything in the test is repeated: same environment, same system, same pro -
AUDIO
36
www.americanradiohistory.com
FEBRUARY, 1967
gram material, but a different group
of subjects, maybe. The tests will repeat in that tight, accurate clusters will
consistently appear for some tests,
with the locations consistently repeating, while for others they will be consistently scattered.
But change environment, system, or
program material, and the results are
apt to change. Some work has been
done to correlate these three variables,
but much more could usefully be done.
From what has been done, environment and system have been found to
be complementary. Large, horn type
units do best in one environment, the
small bookshelf units in another, a
third will be served best by using reflection methods, either integral with
the system or by speaker placement,
while open -back units that radiate as
dipoles, somewhat differently placed,
may be best in some instances (Fig.
13-2)
Assuming that each system is optimally placed in environment to suit it,
program material adds another variable. Some use spaced microphones
to pick up the two channels, or synthesize the channels from a larger
.
number of mikes, placed so as to be
close in to individual instruments or
performers, while other programs are
recorded with a "stereophonic microphone," in which both microphone
elements are mounted together, but
have differently oriented directivity
patterns (Fig. 13-3).
The first two methods will possess
time differences, as well as intensity
differences between channels, although
the close -in mike method will have
mainly intensity differences, for any
program element picked up (e.g. musical instrument or vocalist). The first
has a stereo reverberation effect controlled only by the studio environment.
The second enables precisely controlled reverberation to be used. The last
will have very small time differences
and will rely mainly on intensity dif-
ferential, based on different direction
of sound arrival at the common microphone location.
When these two forms are played
back, one may sound better over one
system and the other over another. So
we have quite a complicated possibility of combinations of the three variables to attempt to evaluate. To cor-
relate these results, another variable
must be carefully checked. Earlier
discussions of stereo either stressed or
poked fun at the need for listeners to
occupy an "ideal position" in the
room, equidistant from the two speakers, leading to the antisocial arrangement of seating in single file (Fig.
13-4).
Actually, the need for this somewhat ridiculous arrangement for optimum appreciation applies only to certain types of recorded material, reproduced over certain systems in certain
environments. Admittedly, unless specific efforts are made to avoid the
need for it, the majority of systems
would require it. But the available
ways to improve this situation are becoming more prevalent all the time.
If the recorded program is essentially "binaural"-that is, the individual channels contain what would he
picked up by ears in a human head,
MUSICIANS OCCUPY THIS AREA
(A)
LEFT MIC
RIGHT MIC
BOOKSHELF UNITS
CORNER HORNS
(B)
(A?
1
\
\
UNITS FACING WALLS
AT ANGLE
,
BAFFLE UNITS IN CHOSEN POSITIONS
Fig. 13-3. Three basic ways in which
program is "miked" for stereo record-
(C)
(D)
different kinds of stereo loudspeaker systems (without indication
of the type of room or furnishing for which each is best suited): (A) large corner
horns; (B) bookshelf units; (C) one way of using wall reflection, particularly recommended by European manufacturers; (D) bipolar (baffle mounted) units.
Fig. 13-2. Some
AUDIO
FEBRUARY, 1967
ing or transmission: (A) two widely spaced mikes, one for each channel;
(B) close -in mikes for each instrument
or performer, location being determined
by electronic mixing (reverberation is
also added with this type); (C) the
"stereo mike"-two directional microphones mounted together with different
directivity.
37
then the best way to listen is with
binaural headphones (Fig. 13-5). A
more comfortable way (but less effective in its illusion of realism) is to
listen to the same type of program
material at an ideal position-at equal
distance from two loudspeakers to
which the same two channels are fed.
But most modern stereophonic material is not recorded this way. Some
is deliberately "piped" into quite separate left and right channels, so as to
achieve a "ping-pong" effect. This
makes wonderful demonstration material, to sell stereo by contrast with the
old monaural, but it can become tiring as a regular listening "diet" and is
not true reproduction of a musical
program as normally performed.
The concept that led to use of an
idealized listening position assumed a
virtual point-source radiator: a pressure -type loudspeaker, with a closed in back, so that sound from a single
unit would always be pin-pointed at
that unit. This method is still used,
but many reproducers use different
means of getting away from this concept as a basic form.
Some units "spread" the apparent
source by the use of reflectors, either
as part of the system (Fig. 13-6) or
by facing the units of conventional
structure toward the walls (Fig. 13-7).
A more effective approach is to use
open back units, that radiate a bipolar
pattern, to radiate a composite wave,
that generates sound wave particle
movement in the vicinity of each listener's head, that will produce the
correct illusion (Fig. 13-8).
APPARENT SOURCE
(el
Fig. 13-8. Bipolar radiators, placed to
suit the listening room, enable quite accurate locations from almost anywhere in the room, and also lose the
sense of identifying the speakers as the
sound sources.
LEFT
MIC
\
RECORDING
/
/
The last-mentioned approach may
seem unnatural to listeners who expect to hear sound "come from the
loudspeaker," because it has the curi-
\
(A)
(C)
Fig. 13-5. Binaural recording: (A), location of mikes,
with or without dummy head (preferably with some
"obstruction" to simulate head); (B), stereo headphones yield greatest realism in reproduction from this
recording, apart from the unnaturalness due to enclosure of the ears; (C) alternative listening, from
PLAYBACK
speakers (equal distance is essential with this type of
recorded material).
(B)
EFFECTIVE
SOURCE
uCLE
ous effect of producing imaginary
sources, not identified with the speaker locations.
When one listens to stereo radiated
from conventional pressure (closed
back) units, although (in a correct listening position, Fig. 13-4) one can
realize an illusion of position for individual instruments, conscious concentration on the location of the speakers
always enables the listener to identify
clearly what he hears in terms of
sound from each unit.
Units faced toward the wall or
other reflecting surfaces have a similar effect, except that the apparent
location of the unit is moved. This
enables a system in a limited space
to serve listeners in that space more
effectively than the direct radiator by
Fig. 13-6. One form of reflection built on to the cabinet design in the form of hinged doors.
4--- EFFECTIVE
SOURCES
'
Fig. 13-7. A preferred form of speaker
placement to project the effective stereo sources much further apart than the
physical structure of the room allows.
The "classic" ideal seating
arrangement for stereo-rather antisocial!
Fig. 13-4.
Check No. 76 on Reader Service Card.
AUDIO
38
www.americanradiohistory.com
FEBRUARY. 1967
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making the actual listening room effectively a small part, located in the
ideal listening position inside a much
larger "image" room. But the method
still suffers from the fact that it can
be recognized as "two-channel" stereo.
When one listens to stereo radiated
from bipolar units, this identification
of two definite sources no longer obtains. If the listener attempts to concentrate on the speaker locations, he
gets the impression that they are not
working, that no sound comes from
these locations, and that the sound
must be coming from "somewhere
else." When such a system does its
job well, even listening at a position
close to one of the units will not enable the listener to identify part of
the sound as coming from that unit.
So, if you want to listen to a system,
with the notion of always being conscious that the sound comes from the
loudspeakers, systems using bipolar
radiators may be a little frustrating,
but it will usually be more realistic,
once this purely artificial desire is dismissed.
So far as source location and separation are concerned, so good. Let's
assume that all a complete documentation of these effects needs is time
and effort and that suitable tests of
sufficient number and diversity are developed and used to correlate a complete set of conclusions. But is separation and source location all stereo
is good for?
Do most of us listen, while trying
to enjoy stereo reproduction, to determine the precise location of every instrument? If we do so, are our eyes
open or closed? If they are closed,
then we also imagine the whole scene
and can probably draw it, or fill in
details on a sketch previously prepared by the psychologist for all subjects to use.
COLLECTION OF SPEAKER SYSTEMS
OPAQUE DRAPES
AUDIENCE SEATING
l,U.1,UJ
CONTROLS TO SELECT SYSTEM
-4
Fig. 13-9. A form of listening room to
provide for "eyes open" comparison,
that allows the imagination to visualize
instrument placement.
If we have our eyes open, we may
still use our imagination, if the whole
reproduction area is concealed by
opaque drapes, so we can imagine the
orchestra, or what -have -you, is set out
just the other side of the drapes we
cannot see through. (Fig. 13-9) .
But not all living rooms, or places
for stereo listening, lend themselves
to this kind of treatment and imagination and the fact that they don't does
not destroy the advantage that good
stereo reproduction can achieve for
the average listener. The fact that the
apparent location of the piano happens to be occupied by a flickering
fire in an open grate, does not destroy
enjoyment. What really makes the
difference?
There we have a question where
psychologists and engineers are equally at a loss. They may conduct a poll
for personal opinions, but the subjective test, as such, begins to lose its
conceptual meaning.
Stereo, if it is good, makes the program sound better. In what way? This
is very difficult to pin down. One
thing seems to emerge from all tests:
it is related to the accuracy of separation, as well as freedom from distortion, including fullness of frequency
response.
Comparison of Systems
So we leave the hypothetical subjective tests and move to some more
concrete-as affects the pocket book:
to find which is the best -sounding system, either for the money, or at any
price? Various groups, independent
testing agencies, sales salons, manufacturers, have set up comparison
facilities in an elaborately prepared
listening environment.
Virtually, this is the only way to
make a quickly assessable comparison
-what is commonly called an A -B
test. It seems hardly practical to say,
"Listen to this, and remember carefully exactly what it sounds like," and
then take the subjects to another listening location and ask them to compare the performance of a different
system in that location with the one
they carry in their memories from the
first. One just cannot carry so many
aspects of audio performance, or the
impression it creates, in one's head.
A very ambitious high-fidelity salon
might conceivably set up a number of
listening rooms, each with different
shape and acoustical environment, or
with adjustable environment features.
so the prospect could first choose the
listening room providing the environment most similar to that in which
he plans to install his equipment. Then
in the chosen listening room, he could
listen to and compare a diversity of
systems, over which any variety of
program could be played to suit the
buyer's taste.
This would be quite an expensive
set-up. completely beyond the reach
of any but the biggest high-fidelity
merchandizing companies, who would
have to carry most of the available
product lines. To make comparison
simpler for the potential buyer, the
selling organization can sensibly narrow down the choice to suit each individual room, by providing in each
kind of room, a selection of the systems that sound best in that room.
The only problem then is that some
customers, not aware of the interdependence between systems and environment, may come in with a notion
that such and such a system is "the
best"-probably based on having heard
it in a different kind of environment
from that planned.
If only the systems suited to the
room intended are available for listening, such a customer may want to
hear the one thought best, to satisfy
his own ears about the judgement. If
the only way for him to hear it is to
go to another room, where the environment does suit the system, his
initial notion will be erroneously confirmed. The only way for him to
realize that it is not similarly ideal for
his chosen environment is to allow
him to hear it in that environment.
Such a variety of listening -environment and complexity -of -system arrangements in each would be quite an
expensive set-up, possible only for
large-scale merchandizing operations.
Most salons must content themselves
with one listening room, organized to
be as typical as possible of the average
listening room that customers of the
locality are likely to have and with
being well enough informed to do the
best possible job of providing reliable
advice beyond the range available for
actual demonstration.
Having thus covered most of the
measurements connected with individual items of equipment and with systems as a whole, including some comments on subjective aspects, in which
area there is still much more work to
be done, we will turn, in the next installment, to some of the measurements that become necessary within
certain components: those concerned
either with finding out why a unit
does not function as it should, or with
finding ways and means of improving
performance.
Much of this is concerned with
correctly interpreting measurements
made, which may not always mean
what they apparently obviously indiaE
cate!
AUDIO
40
www.americanradiohistory.com
FEBRUARY, 1967
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AUDIO
I
N TERNAT
BOX 1000, ELKHART, INDIANA 46514
FEERUARY, 1967
Check No. 77 on Reader Service Card.
I
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PHONE (219) 523-4919
41
Jazz in Greenwich Village
LARRY ZIDL
The recording group on the cover is
proof that the sort of equipment available to the hobbyist is more than able
meet the most stringent recording
needs.
The cover artists are as follows: Bobby
drums,
cornet, Ray Mosca
Hackett
Bob Knutzen-trombone, David C. Sibley-bass, Dave McKenna-piano, and
Pee Wee Russell-clarinet.
You will note that there is a triangular device in Bobby Hackett's horn.
This is a special Koss transducer designed for this kind of instrument. It
allows the lower -efficiency musical instrument to compete in sheer decibel output with electric guitars and other high volume instruments. It means that a live
artist can move about while a fixed
microphone gets an ideal picture of the
instrument; one that does not vary as
the artist roams about the stage. (See
p. 64.)
The place is Greenwich Village's Half Note Club on the night of October 18th.
Robert Bowman of Tandberg sits on the
to
-
-
Fig. 2. The
left, John Koss of the company that
bears his name is on the right. They
assembled this recording session with a
unique project in mind.
Most conventional stereo recordings
are made (in essence) with widely
spaced channel pickups. This creates a
dramatic earphone effect to be sure, but
it was the effort of this session to produce a master tape that was recorded
binaurally. (Do you remember that
word?) Binaural recordings are made
with the microphones placed apart in
the same way as your ears are placed
apart. The purpose of these sessions was
to produce a binaural master that could
be converted to disc.
Two recorders are used. Both are
Tandbergs. One is the new 64X. It
features an extra bias head on the reverse side of the tape and a solid-state
bias oscillator circuit. Frequency response at the top speed of 71 ips is
çRP-4 WIND PICKUP
V
'LE WEE
RUSSELL
BOBBY
HACKETT
GRAMPIAN
DP
BOBEa7
BOWMAN
Fig. 1. The equipment and personnel on the cover.
42
-4A
second group.
±2 dB over the range of 30-20,000 Hz.
But this machine was used primarily at
33/4 where its response is ±2 dB, 3015,000 Hz.
The machine used to record the 71/2
ips master for future binaural discing
is a Tandberg 62 half-track recorder.
This is otherwise similar to the 64X
though we understand it does not have
the reverse -bias head.
Two microphones each were used. The
64X was fed from two Grampian DP
4H high-impedance units. These were
spaced about 8 -feet apart.
The binaural recording was made
through a pair of Norelco/AKG D-24
units. These are low -impedance microphones so a pair of transformers was
necessary to match them to the Tand berg. Both sets of microphones were
actually placed about 8 feet out into
the audience but are shown otherwise
for the pictures.
The Acoustech V -A integrated amplifier was used in conjunction with a Koss
Model 1220 monitoring headphone amplifier. The headphones are the Koss
Model KO -727 and Model PRO -4A.
There were two separate recording
sessions on that same day. The second
group which didn't make our cover did
make the tapes. The personnel here (Fig.
2) were Zoot Sims-sax, Steven Schaeffer-drums, David Frishberg-piano, and
Major Holly Jr.-bass.
The home recordist can learn something significant from these sessions
(which may be released as a binaural
recording by the Koss-Rek-O-Kut company). The primary lesson is to use top grade equipment in peak operating condition. Also, to monitor everything while
recording-so that technical errors may
be quickly corrected). Finally note the
quality microphones. These transducers
are your "window on the performance."
You simply cannot get quality out of
low-grade mikes.
It is worthy of note that our informant
tells us that the recordings made on
either machine (one at 71 and the other
at 3/ ) are indistinguishable as far as
audible frequency response is concerned.
That is the present state of the tape art
far cry from what was standard just
a few years ago.
-a
AUDIO
FEBRUARY, 1967
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AUDIO
43
FEBRUARY. 1967
www.americanradiohistory.com
MUSIC AND
RECORD REVIEW
Record Review
Edward Tatnall Canby
Light Listening
Chester Santon
Jazz & All That
Bertram Stanleigh
You Take the High Road
..
.
Brahms: Piano Concerto
No. 1 in D Minor. Boston Symphony,
Leinsdorf.
RCA Victor LSC 2917 stereo
Ah-up with high priced records and
down with all cheap labels! That's the
inevitable and healthy reaction to this
superb, but necessarily high-priced item,
with RCA's ever -improving mainstay
pianist, Arthur Rubinstein. You can't
have Rubinstein for peanuts. Not even
for $2.50. He's worth double.
There's a long, passionate orchestral
introduction to this concerto. When, at
last Rubinstein's piano enters, you know
instantly that he has been following every
second of the music, that he's with
a part of the whole. So many of the
brilliant young prize winners sit there,
figuratively, saying just wait until they
hear ME. That's how they sound.
There's a famous long solo melody
here, too, one of those massive Brahms
piano themes that knock you for a loop
when you first hear them. Rubinstein
plays it with all his persuasiveness-but
how wonderfully it fades down, suddenly, at the end, to meet the incoming
orchestra at exactly the right piano volume. He's with it again.
Rubinstein does better than the Boston
here, and better than Leinsdorf himself;
but it doesn't matter. The concerto is
far and away ahead of a hundred lesser
versions with men of less profound experience than Rubinstein in his superE.T.C.
vital old age.
Rubinstein,
Record Review
Edward Tatnall Canby
it-
Sofa Cushion Sound
R. Strauss: Alpine Symphony.
Bavarian State Orch., Strauss (1941)
Seraphim 60006 mono
To filter or not to filter? That
would seem to be the question here.
This is a famous war -time oldie 78,
conducted in Germany by Strauss
himself and (obviously) acquired
later on by Angel -EMI in England.
It is worthy material, all right, a
document of the sort that Angel has
been putting on its much more expensive COLH label, with those
superb little gray booklets of fact
and background tucked inside. At the
low Seraphim price-no booklet. But
there are good notes on the back,
of course. And the sound, I'd guess,
is precisely what it would have been
in the high -price packaging. Alas.
Nobody, but nobody else (unless
maybe RCA Victor) would dare put
out this fine grade of felt -lined, drab gray, sofa cushion non -hi-fi! It all
comes through a sharp cut-off filter,
if I'm guessing right, at maybe 3500
Hz, and there's a nasty hollow midrange peak as a result. All dull bass,
no highs whatsoever and a wet
blanket effect from start to finish.
Poor Strauss! The finest orchestral
colorist of his generation. Buried in
sonic pillows.
Did it have to be this way? Did
the original sound like this? I can't
believe it. I am sure that, somehow,
a more imaginative re-creation might
have been possible, even at the risk of
a bit of outright distortion here and
there (horrors! On Angel?) and maybe a lot of plain old hiss. Remember those shattering 78 inner -groove
sounds, full -volume? We took them
because of the better sound on the
outer grooves. We still could, I think,
if the situation were honestly explained to us. Well worth it. And
who's afraid of a bit of hiss?
'Course, just maybe, the original
discs sounded just like this, in which
case not a thing could be done (unless perhaps a violent "presence peak"
to add a bit of color contrast). I
can't believe it-even in war time.
After all, remember the Magnetophon.
Yes, the Alpine Symphony gets
through all right, at least by inference. And it goes on and on and on.
Its only glory, alas, is the superb
orchestral color that ain't there. The
music is pretty interminable, even
with Strauss at the helm. Some document!
E.T.C.
Brahms: Complete Piano Works, vol. 6:
Schumann Variations Op. 9, Vars. on
an Original Theme Op. 21/1, Vars. on
a Hungarian Song Op. 21/2. Julius
Katchen.
London CS 6477 stereo
Three big sets of early Brahms piano
variations, out of his youthful period,
and it will take a pretty solid understanding of the early Romantic idiom
if you are to make sense out of them:
for these are the mooniest, moodiest
effusions of youthful ardor you're ever
likely to hear! Brahms was very much
"in" with his time, back then. And
AUDIO
44
www.americanradiohistory.com
FEBRUARY, 1967
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what people wanted from youth was unabashed pathos, long hair and plenty of
sweet anguishing and languishing.
Mr. Katchen doesn't entirely help
these super -Romantic effusions by his
own super -Romantic, or should I say,
neo -Romantic treatment, all hesitations,
ardor, rubato and pathos -deluxe. He is
musical, decidedly, in this style. And
probably right, too-for surely Brahms
himself was even more soulful at the
piano, in those days. But the constant
slowings-down, the hesitations and the
tearful agitation, while utterly musical,
are also hard on the listener; for you
can't easily keep track of the music itself. A more straightforward, even -paced
playing would be much easier on the
novice listener and perhaps more stylish
for today, as well.
Of its neo -Romantic type, Mr. Katchen's playing is the very best. A second
and third try and you'll get the sense
E.T.C.
plenty well, rubato or no.
Joseph Szigeti. Sonatas by Debussy,
Honegger, Four Pieces Op. 7 by Webern.
Roy Bogas, piano.
Mercury SR 90442 stereo
Szigeti was one of the world's great
violinists back before the war. Then a
sort of shaking palsy of the fiddle fingers
slowed him down and reduced his usefulness to record companies. The painfully slow vibrato and seemingly shaky
technique just was too much for most
listeners, at close range.
But the old man didn't quit by any
means. He is a great musician in his
brain and experience, with a tremendous
knowledge of the violin literature and
its many styles. Mercury was wise to
grab him.
In this typical Szigeti program the
old slightly cold-in -the -head wiry tone
is still evident, as is the weakness of
control over pitch and vibrato-but in
a minimum fashion. He has improved.
And the engineers have put him well
back, in the newer stereo style, surrounded by big liveness and a full piano
tone. (Roy Bogas is excellent.) That
brings out the best and suppresses the
worst, decidedly. A happy solution and
very musical.
And so the old violinist does some
superb things here. The perfect styling
of the Debussy sonata could not be
bettered by anybody. The squeaky Webern tidbits are equally savvy. The more
conventional Honegger and the folksy
Ives are done with the right brashness
and outwardness. A good record. E.T.C.
Handel: 15 Sonatas for Violin with
Harpsichord. Henry Temianka; Malcolm
Hamilton, hps.
Everest 3143/3 (3) stereo
whole sides' worth of Handel
sonata music here, and a number of
extra musical birds are killed with one
stone since these works are also known
variously as oboe, flute or recorder sonatas-depending on who's playing. (Handel was quite permissive; he listed all
of these as alternative solo instruments.)
In addition, Handel being an inveterate
Six
borrower of his own music, you'll hear
other familiar music in these-from, say,
the "Water Music" and one of the concerti with oboes. An all-around, generalpurpose Handel concert, in spite of the
unchanging pair of instruments.
Mr. Temianka, of the old school, plays
very musically but in a now old-fashioned way, his tone sweet and melting,
like Fritz Kreisler's, his ornaments mere
blobs rather than the now -normal clean
Baroque trills, his expression full of
those gentle little sobs and sighs that
used to be the pride of the virtuoso
violinist! All this on a very restrained
scale and audible mainly for the ear
that is well up on Baroque music; the
rest of the ears won't notice the difference-and so will find the playing a
pleasure.
A forthright, well balanced harpsichord continuo from Malcolm Hamilton's harpsichord, a bit blocky in style.
E.T.C.
Mahler: Symphony No. 7. N. Y. Philharmonic, Bernstein.
Columbia M2S 739 stereo
This enormous symphony, the least
often heard of Mahler's nine (plus a
tenth, left unfinished and recently completed and recorded) typically occupies
four whole LP sides-and long ones, at
that. The outer movements are perhaps
the toughest, for they are full of that
apocalyptic sense of cosmos -shaking importance which thrills some of us and
leaves the rest wondering whether Mahler
composing was somehow like Moses receiving the Commandments from the
Lord. It is splendid music and yet, too,
it is terribly egoistic.
The inner movements tend to the two
songs and
inevitables in Mahler
marches. Though they do go on and
on, they are often lovely and/or impressively musical. I liked particularly
the dramatic next-to -last movement (out
of five), scored for relatively small
"chamber" orchestra. It sounds out wonderfully well on records.
Yes, Bernstein has a way with this
ultimate Romanticism. It is good-as the
quoted critics say on the front cover.
But the first and last (apocalyptic) movements are just a bit uneven, as though
the Philharmonic hadn't yet quite got
on top of their many complexities.
-
E.T.C.
Albert
Roussel: Symphonies No. 3,
No. 4.
(a) Paris Conservatory Orch., Cluytens.
Angel 36327 stereo
(b) Lamoureux Orch., Munch.
Epic BC 1318 stereo
Did you ever! Two discs identical in
content, with two notable French orchestras and a pair of very big French
conductors-and the records were released in the very same month. Somebody's spies were asleep at the switch.
Roussel is one of those slickly professional big -orchestra composers (he
died in 1937) whose music uses the
large Romantic orchestra and its styling,
but modified for the modern period by
more dissonance, a harder sound and
an augmented decibel potential. As we
listen to these works, from 1930 and
1934, they seem excessively thick and
dense in texture and surprisingly oldfashioned, for all their dissonance. Our
ears prefer a more streamlined sound
now, both in modern music and the
revived older Baroque and the like.
Frankly, Roussel gives my ears indigestion, though I do admire his professional
touch.
Angel's recording comes over best.
Conducted by one of the outstanding
older French conductors, played by one
of the best known of French orchestras,
which can play French music superbly
(that is, when it feels like playing well
-which isn't always), this record has
a mellow quality, a gentleness of approach, that puts Roussel in an optimum
musical light. The recording, of Angel's
somewhat distantly mellow conservative
sort, fits the musical conception perfectly.
Epic's Lamoureux orchestra is conducted by the ex -conductor of the Boston
Symphony, who is at his best in his own
nation's music, especially of the more
Romantic sort. But the well -remembered
Munch hardness of approach, the driving, unmusical beat, too familiar in many
a dull performance of the classics in
Boston, is only too easily heard here.
Where Cluytens leads his men through
Roussel, Munch pushes and drives them.
Oddly in line with this, the Epic sound
is brighter, harder and closer than
Angel's. It could be called a "hi-fi"
sound, except that it seems to me a bit
harsh in the balance (though not in
terms of distortion) with overly brilliant
highs and an absence of solid middle orchestra sound. Mike pickup and acoustics, I'd guess. The recording is by
Erato.
E.T.C.
Baroque Italian Concertos by Vivaldi,
Geminiani, Locatelli, Albinoni. I Solisti
Veneti, Scimone.
CBS 32 11 0004 stereo
Here's that odd bright -blue CBS label
again and I'm still at a loss (since nobody tells me) as to why it is different
from Columbia regular. Or Epic. They
all sell at regular (high) prices.
In England, CBS is the Columbia
name, to distinguish it from the older
British Columbia label. But here?
Now look here, Columbia -CBS! Are
you starting in at the Baroque import
game with this price scale? Don't you
know that at least a billion Baroque
records have already been brought out,
via similar imported European music, on
many a new low-priced label? Why the
higher price here?
The Solisti Veneti are, of course, another of those new small virtuoso Italian
groups that have followed the famed I
Musici, reacting violently to the old
methods, substituting overly small ensemble sound for overly large, playing
chastely and fast, instead of opulently
and slow. It's all very nice, but I don't
find these players so very different from
others of the sort on various labels.
AUDIO
46
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FEBRUARY, 1967
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They're good. The music they have
chosen varies from OK to very dull.
Nothing to make such a big fuss about.
You can't "revitalize" a Vivaldi concerto that just isn't one of his masterpieces, to put it mildly. Try side 2 if
you want the best here-Geminiani and
Albinoni.
E.T.C.
... and I'll Take the Low Road
Stravinsky: Les Noces; Pribaoutki; Berceuses du chat; Four Russian Songs;
Four Russian Peasant Songs. Soloists
and Chorus of the Orch. du Theatre
National de l'Opera, Boulez.
Nonesuch H-71133 stereo
Nonesuch has latched onto a couple
of top -grade celebrity winners in this
and its companion low-priced disc, Le
Sacre du Printemps. Pierre Boulez is
France's coming Toscanini, not to mention her big hope as an avant-garde composer and general musical practitioner.
It's safe to say he'll soon be turning up
on major celebrity labels-better grab
him here while Nonesuch has him.
The major item (side 1), Les Noces
is out of the early 'teens, Stravinsky's
still -Russian wild period that began with
Le Sacre, sophisticated yet violently
primitive. This final version of Les Noces
is scored for solo singers and four pianos
-phew! If you like Le Sacre you'll like
this, especially with the dynamic Boulez.
The other works are short, out of the
same period, for assorted voices and odd
instrumental combos. One is for mezzo
soprano and three clarinets. Another
uses a women's chorus and four horns.
An important Stravinsky record and
a good show, any way you listen to it.
E.T.C.
Ravel: Daphnis and Chloe Suite No. 1;
Bolero; La Valse; Alborada del Grazioso.
Czech Philharmonic, Baudo.
Crossroads 22 16 0040 stereo
Coming from such an unlikely place,
out of old Bohemia, this Ravel is extraordinarily good. The playing is both
enthusiastic and understanding, bringing
out the essential Ravel as one would
not think the Czechs could do. They
have the right idea, exactly-that curious
contradiction between urbanity and madness, fine -lined control and utter abandon, which is always near the surface
in Ravel's music. Here are his major
works of the sort; each one of them
has the same succession of increasingly
intense, farther -and -farther -out climaxes,
first the splendid Daphnis music with
its frenzied wordless chorus and wild
rhythms; then the apotheosis of the
waltz, La Valse, Johann Strauss carried
to tortured, yet beautiful madness, ending in a horrendous grimace of terror;
the famous Bolero, a stylized version of
the same progression, a tour-de-forceand finally, an earlier work of the same
genre, the Alborada del Grazioso, all
Spanish rhythms again.
In each of these the Czech orchestra
has grasped the sense of the music, the
wildness, so perfectly controlled, the
agonized ravings composed into music
of incredible precision. The last few
48
"paragraphs" of La Valse are superbly
done; the sudden change of key at the
end of the Bolero never sounded so
startling, and the pounding chorus of
Daphnis and Chloe reminds us how
close is this music to Stravinsky's Le
Sacre du Printemps-it came only a year
before.
The Crossroads sound here is smoother
and less edgy than that of the first
batch of releases; indeed, far from being
edgy, it is a bit on the dull side. A
slight boost of the highs and plenty of
volume bring out the best in the music.
Epic evidently still has a problem in
adapting the Czech Supraphon tapes to
American standards.
E.T.C.
The Fitzwilliam Virginal Book. Blanche
Winogron, virginals.
Dover HCR ST 7015 stereo
This is a superb record! The Dover
mail-order catalogue (180 Varick St.,
New York, N.Y. 10014) continues to
amaze; for its records, many of them
brand new and in stereo, sell for the
lowest official price anywhere, except
for Vanguard's equally superb Everyman
series. The $2 tab for these is well below
the $2.49 list asked by most of the
new low-cost labels. (Discounts, of
course, play hob with all sorts of prices.)
The Fitzwilliam Virginal(s) Book is
a famous Elizabethan collection of keyboard pieces intended for the virginals,
the tiny one -stop harpsichord, table model type, that was then the rage.
The music is now very popular among
home pianists. It is available in a low price printed edition too.
All I can say is that you will be
amazed what can be done with this little
instrument, with its single, unvarying
tone color and fixed volume level,
through sheer expertise in the playing.
Never a dull moment in these excerpts
from the collection, and there are many
works of a virtuosity hard to believe.
Miss Winogron knows more about playing music on the harpsichord -type keyboard than all the other keyboardists
put together. They should study her here
for hours and hours. All you have to
do is just enjoy.
E.T.C.
Boris Christoff
-
Mussorgsky Songs.
French Nat. Radio Orch., Tzipine.
Seraphim 5008 mono
Boris Christoff, successor to many a
great Moussorgsky-type basso
those
cavernously enormous voices that sing
Boris Goudonov, the dying Tzar, and
Hans Sachs, Wotan and the like in Wagner-has specialized in Moussorgsky interpretation though, if I remember rightly, he is Greek born. These splendid EMI
records have given the reissue engineers
no great problems. The voice comes
through most effectively. The recording
has everything but stereo. It might as
well be brand new.
In these relatively intimate songs,
which were originally composed with
piano accompaniment, Christoff seems
almost a bull in a china shop-except
that Moussorgsky himself had intended
to orchestrate some of them and, in
any case, he always thought big, what-
-
ever he wrote. Witness the well known
Pictures at an Exhibition, originally for
piano too. The Christoff vocal production and the diction are both superbly
dramatic. A stunning basso -baritone!
Others, though, have done these songs
to good effect in a much more intimate
fashion-several women included. They
can be very subtle.
Side 1 is the Songs and Dances of
Death. Gruesome. Side 2 offers four
separate songs, also orchestrated from
the original piano versions.
E.T.C.
Four Rococo Quartets. (Rosetti, Ditters
von Dittersdorf, Richter, Asplmayr).
Oistersek String Quartet.
World Series PHC 9026 stereo/mono
For anyone who has a yen for the
string quartet, these prototype models
of the breed, so to speak, are quite
fascinating. And they are beautifully
played, too. A strong, accurate group,
this Oistersek ensemble, with a good lead
violin and an active cello to back up
on the bottom and balance the inner
pair of instruments.
Oldest man here is Richter, born in
1709, thirty years before Haydn and
almost a half century before Mozart-Haydn and Mozart being the end -product
composers in the style we hear emerging
in these works. Richter's first movement
instantly gives itself away; the tell -tale
Baroque sound of the figured bass is
still there, the cello sawing at lines and
lines of repeated harmony -bass notes.
But he tries valiantly and gets the cello
into the action often enough-he knew
where he was heading. And Richter knew
all the elegant "Mannheim" tricks of
melody and ornament that were then
coming in, around the time of Bach's
death in the 1750's and on. Good man.
Ditters von D., friend of Mozart and
Haydn in Vienna and Haydn's age, is
much more suavely elegant and not particularly exciting. He was no pioneer in
the new and untried! As for the completely Viennese Asplmayr (now there's
a name for you
.
.) he was ever so
definitely a minor operator on the scene
in the same period; he'll help you gain
perspective on the bigger men, at least.
The best of these, for my ear, is
Rosetti, who was actually named Roessler, out of (German) Bohemia, recently
known to us as the Sudetanland, one of
Hitler's little conquests. Rosetti wrote a
Requiem in Mozart's memory and he
writes a really expressive quartet, a lot
more than mere formula.
E.T.C.
.
J. S. Bach: Sinfonia, BWV 1046A; Sin-
fonie from Cantatas. Deutsche Bachsolisten, Winschermann; Cologne Soloists
Ensemble, Muller-Bruhl.
Nonesuch H 71120 stereo
This odd looking collection of unheard-of Bach turns out to be largely
familiar material-in alternative versions.
Bach re -used large numbers of his earlier
works in new forms, often a number of
times.
Thus the first "sinfonia" (an orchestral
piece, in Bach's time often in one movement and used as an introduction-an
overture) is no less than an earlier ver-
AUDIO
FEBRUARY, 1967
If you buy "Bargain" tape...
you should have your HEAD examined!
SONY
PA150
After that, see the man who sells Sony tape!
And Sony Tape was developed to make a Sony-or any
other recorder-perform at its best. Sony Tape is permanently lubricated by the exclusive Lubri-Cushion
process. Sony's extra -heavy Oxi-Coating won't shred or
sliver and is applied so evenly Sony Tape never has high or low -spots. What's all this mean to you? Sony Tape
captures and reproduces the strength and delicacy of
And Sony
every sound-over and over and over again.
Tape has something else no other tape has at any price
Each box contains a pair of "easy -threader" tabs to make
any tape reel instantly self-threading. It's the best thing
to happen to recording tape since ... well, since SONY.
If you've been using any of the so-called "bargain" tapes
for a while, chances are you should have a repairman
examine your recorder's heads. Because the odds are good
the heads are excessively worn. If they are, you can
thank the "bargain" tape's thin-coat lubricants which
rub-off and cause friction, and weak "bargain" oxide
coatings which shred and gum -up the heads. Naturally,
your recorder stops sounding as good as it used to
Want to restore a factory -fresh "voice" to your recorder?
See the man who sells Sony Professional Recording Tape.
He has a high regard for tape recorders (after all, he
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AUDIO
FEBRUARY,
1967
49
sion of the Brandenburg Concerto No. I,
minus a couple of sections added later
and with one unfamiliar part. The other
works are all taken from cantatas; but
several were previously parts of instrumental concerti, now mostly lost. Some
of these movements will be familiar to
many ears, in assorted arrangements that
have long been popular.
The performances are conscientious
and earnest, a trace on the heavy side.
(But isn't it Bach's fault, not theirs?)
The horns and oboes in the First Brandenburg prototype are excellent, as
is the solo oboe in the familiar F major
E.T.C.
Sinfonia, BWV 156.
Praetorius: Christmas Music; Dances
from "Terpsichore."
Schein: Two Suites from "Banchetto
musicale." Ferd. Conrad Instr. Ens.,
Niedersachsischer Singkreis, Trader.
Nonesuch
H
71129 stereo
Three musical sections for this pleasant
disc of old music out of the early 17th
century. The Praetorius Xmas consists
of pairs of settings of Christmas tunes
(chorales), first for a charming and
modest ensemble of old instruments, including the kazoo -like instrument in the
shape of a J, the Krummhorn; then, in
another version, for instruments plus a
sturdy boys' and men's choir. The Praetorius dances, written for actual (court)
dancing, are energetic little bits of tunefulness played here by a recorder group
plus percussion.
Schein's dances are of a slightly later
sort, already grouped into suites for
listening use. Some are much like the
Praetorius dances; others, more serious,
already begin to suggest the later "dance
suite" (for listening) of J. S. Bach-a
E.T.C.
century later.
Corrette: Concertos Comiques. Antiqua
Musica Chamber Orch., Roussel.
World Series PHC 9012 stereo/mono
These little French -Baroque concerti,
more or less after the Italian manner
(Vivaldi, etc.), are "'humorous" in that
each is built on a popular French song
of the time. I even recognized one myself, after all these centuries. To the
savvy aristocracy of early 18th century
Paris they must have been side-splitting,
a bit like P.D.Q. Bach or the Hoffnung
concerts, today.
They are of very slight substance,
though full of gaiety in musical terms.
I found them dull, however, because they
are all alike and all in the same limited
set of keys, with precious little contrast.
I wouldn't suggest playing them straight
through without a break.
A more serious reservation is the utterly zany "arrangement" of each of
these by a lady named Huguette Grémy,
for a group of Paris Conservatory wind
players backed by strings. Yes, she uses
instruments available at that time; but
her styling of them is wholly out of the
period, a mixture of late Mozart and
Handel -Beecham, I'd call it. If you'll
accept these pieces simply as modern
transcriptions, à la ballet music, you'll
be happy. But if you want your Baroque
-even French Baroque-to sound like
it oughta sound, then don't expect to
be pleased. You'll only he baffled. E.T.C.
50
Light Listening
Solid State: Passion Guitars
United Artists SS 18007
IN SEVERAL RESPECTS, this is the best
sounding disc I've heard of the new
breed of recordings beginning to use
solid-state componentry in their process
of manufacture. So impressive is the
job this record does on upper -frequency
transients of guitars and percussion, I
am tempted to call the disc one of the
best sounding I've heard-no matter
what processing componentry was used.
While my neck is out, I'll inch it forward a bit more with the following observation. Records utilizing solid-state
electronics in most stages of production,
if made the way United Artists makes
them, will go a long way toward resolving arguments still in existence between proponents of transistor gear and
those who prefer vacuum tubes in home
music systems. If you want the best of
both worlds, try this disc through a topnotch system using tubes and you'll see
what I mean by the phrase. The combination is very effective. You'll get a
cleaner top -end sound than you do with
a conventional record while still enjoying the rounded warmth in the rest of
the spectrum that tubes alone seem to
be able to deliver. The recording curve
is standard RIAA yet I find the treble
variable roll off knob can be left in a
flat position, something I cannot do with
comfort with most pop records. That's
as good a sign as any of the genuine
cleanliness in the upper frequencies.
Three quarters of the time in this album
percussion in profuse variety occupies
the spotlight with four classical guitars
assigned to the melody of old standard
pop tunes. Each guitar has its own condenser mike placed, in the accompanying photos at least, two inches from the
player's right hand. The scraping and
tinkling elements of the percussion section must have enjoyed a few more
inches of room. Nothing on the record
sounds tubby. It's just that the percussion has a slight advantage in transparency. Even if you now have a special
stereo disc used primarily to check the
response of your system with percussive instruments, get this album to find
out how much difference solid-state processing can make in a reference record.
C.S.
The Apple Tree (Original Broadway Cast)
Columbia KOS 3020
With the appearance of a new show
by the team responsible for the long running Fiddler on the Roof, the 1966'67 season for Broadway musicals can
be considered officially under way. Jerry
Bock (music) and Sheldon Harnick
(lyrics) are creators of musicals almost
as well known to record buyers as they
Chester Santon
are to Main Stem habitués. The Apple
Tree follows such worthy productions
as the Pulitzer prize winning Fiorello,
Tenderloin and She Loves Me in addition to the more recent Fiddler. Young
Barbara Harris is very much the star
in their latest musical. She has even
more to do than in On A Clear Day
You Can See Forever, her last major
show. This is all to the good because her
singing and acting talent is one of the
very few tonic factors to hit Broadway
in recent years. In her latest show the
producers have solved one of the large
problems facing the musical theatre today: a thin plot spread over an entire
evening. The Apple Tree is made up of
three separate stories, each one taking
an act of the musical. The trio of tales
is based on writings of Mark Twain,
Frank R. Stockton and Jules Feiffer.
Miss Harris and Alan Alda appear in
all three "pocket-size" musicals while
Larry Blyden joins them in the first two.
Twain's Diary of Adam and Eve is easily
the most appealing of the three stories
and the most successful in establishing
mood in the recorded form. The best
songs of the entire production are to be
found in this whimsical episode as Adam
and Eve stumble upon bewildering discoveries that only initial humans had to
cope with. A good example of the touching lyrics in this tale is a lullaby titled
Go to Sleep, Whatever You Are and
It's a Fish. Stockton's famous Lady or
the Tiger is an excuse for exotic -type
music befitting the gaudy trappings of
an imaginary kingdom. Bock and Har nick are a little out of their element
here. The third playlet, Jules Feiffer's
Passionella gives Barbara Harris a field
day as a necessarily dark-haired chimney
sweep-yes, I said chimney sweep-who
finds herself transformed in her dreams
into an extremely blond movie star. Any
original cast album is, at best, only a
capsule version of a musical show. The
coverage of three plots on one disc
means the length of The Apple Tree's
songs have had to be held down to a
minimum. The record is over before
you know it but this can be a considerable blessing if you've ever sat through
a tedious show album with very little
story line to sustain long songs. The
sound provided for the home listener by
Columbia's engineers is right up there
with the very best they've ever done,
which means it's as good as you'll hear
in a musical on records.
C.S.
Henry Mancini: Music of Hawaii
RCA Victor LSP 3713
This album will be of more than
passing interest to anyone intrigued by
new instruments that produce their
sound with the help of electronics. In
his first album devoted to music about
AUDIO
FEBRUARY, 1967
not all
cardioid microphones
are alike ...
the
SHURE
TRUE CARDIOID UNIDIRECTIONAL DYNAMIC
MICROPHONE SOLVES ALL THESE
COMMON MICROPHONE PROBLEMS!
PROBLEMS CAUSED BY INEFFICIENT REJECTION OF UNWANTED SOUNDS BY THE MICROPHONE
SITUATION
PROBLEM
CAUSES
SOLUTION
REFLECTIONS
Feedback occurs where a
so-called "cardioid" microphone is used and the
speakers are placed to the
rear of the microphone. A
common occurrence in
churches, auditoriums, and
meeting rooms.
Sound bounces off hard surfaces
on the walls, floor and ceiling,
in and around the audience area
and the microphone used is
not effective in rejecting these
sounds at all frequencies, and
in all planes about its axis.
The Unidyne Ill rejects sound
at the rear with uniformity at
all frequencies. Sounds bouncing off floor or other surfaces
are uniformly rejected.
Unexplained feedback. Column loudspeakers are used
to distribute sound more
evenly to the audience in
churches and auditoriums.
Feedback occurs when rear and
The
side sound lobes of column
speakers coincide with rear and
side lobes of so-called ''cardioid" microphones.
or side lobes. Thus it rejects
the side and rear lobes of the
sound column speakers.
A disturbing, echoing effect
Low frequency reverberation and
The Unidyne
boominess occuring when microphone fails to retain unidirectional characteristics at low
frequencies.
uniform pattern of sound rejection at all frequencies, even
as low as 70 cps. The response
has a controlled roll -off of the
low end-low frequency reverberation diminishes effect of
boomy hall.
COLUMN
LOUDSPEAKERS
of low frequency sound often
found in churches, large auditoriums, and arenas.
REVERBERANT
Unidyne Ill solves this
problem because it has no rear
Ill maintains
a
PROBLEMS CAUSED BY THE MICROPHONE'S INEFFECTIVENESS IN PICKING UP THE DESIRED SOUND
GROUP COVERAGE
WITH ONE MICROPHONE
.r
{(r)
USING MULTIPLE
MICROPHONES
single microphone does
not provide uniform coverage of a group. This is
commonly experienced with
choral groups, quartettes, instrumental combos, and
speaker panels.
The particular "cardioid" microphone used lacks a uniform
Variation in the pickup level
and tonal quality exists
throughout the broad area to
be covered. This may occur
in stage pickup of musical
and dramatic productions.
panels and audience partici
pation events.
The pickup pattern of the micro-
A
pickup pattern, so that persons
in different positions within the
general pickup area of the
microphone are heard with varying tonal quality and volume.
phones used is too narrow,
causing "holes" and "hot spots."
The off -axis frequency response
of the microphones also varies.
The Unidyne Ill affords uniform pickup of the group with
a
resulting consistency in vol-
ume and sound quality among
the members of the group.
The Unidyne
Ill permits
smoothness in pickup as true
cardioid pattern gives broad
coverage with uniformity
throughout coverage area.
Eliminates "holes," "hot
spots," and variations in sound
quality, simplifies blending
many microphones.
DISTANT PICKUP
14.
\7j)
Too much background noke
or feedback results when
working with microphone
at
desired distance from sound
source.
Long-range microphones are less
directional with lower frequencies. Lobes or hot spots allow
background noise or feedback.
Use the Unidyne III to gain
relatively long range with effective rejection of sound at
all frequencies at the rear of
the microphone.
SHURE BROTHERS, INC., 222 HARTREY AVE., EVANSTON, ILL. 60204
AUDIO
FEBRUARY. 1967
Check No. 82 on Render Service Card.
51
Hawaii, Henry Mancini, in addition to
leading the chorus and orchestra in his
own arrangements, also found time to
play an electronic harpsichord just coming on the market when the record was
made. He performs at the keyboard of
a Baldwin Solid Body Harpsichord. It's
not exactly clear from the overall tonal
effect of the album why he chose the
instrument for Hawaiian music. Its full
possibilities will have to await further
exploration by other arrangers in some
other musical context. According to a
spokesman for Baldwin at their New
York office, their new device weighs only
85 .pounds in a body that is about 54
inches long. The keyboard is built to
standard organ specifications. The strings
are still plucked, but guitar -type pickups
have replaced the traditional soundboard
and a two-channel Baldwin amplifier has
been added. Separate pickups at the
center of the strings and at the bridge
end give the player a choice of two completely different tonal effects. The range
is five and three-quarter octaves and the
tonal combinations, awaiting more exploration on future records, are brought
about by mixing the pickup patterns
with and without mute and multiplying
them by the amplifier tone controls. Said
amplifier also provides tremolo and reverberation. For the most part, Mancini
uses the Baldwin solid Body Harpsichord to produce the effect of a fullervoiced lead guitar. In some selections,
he settles for a quieter sound somewhat
similar to the celeste. If there is a lot
of flexibility inherent in the design of
the instrument, it isn't particularly obvious in this album. Mancini at least
C.S.
breaks the ice.
Winchester Cathedral
Fontana SRF 67560
There are several reasons why this
column makes little effort to discuss the
topmost hit records on the popularity
charts. These are the truly smash hits
in popular music that come from nowhere only to disappear within a few
months. In keeping up with such phenomena, the time element is more than
I can hope to cope with. Only a weekly
magazine could attempt to chart the
meteoric rise and fall of an all-out
crowd pleaser. The problems of reviewing such momentary favorites can be
overlooked in the case of Winchester
Cathedral on the Fontana label. Here
is an exception to just about any rule
you would care to mention. As performed by the New Vaudeville Band,
the Cathedral may well revive a trend
that could be with us for some time
after this review reaches print. Music
based on the styles of the 1920's and
'30's has not been an unknown commodity on recent records but this disc
is different on several counts. Winchester
Cathedral is funnier than most throwbacks to the Twenties. An era that had
its share of incongruous titles and inane
lyrics in its popular songs has never
been mirrored with such deadly accuracy
by a young member of our generation.
If you like 'em far out, this is the song
for you. Geoff Stephens got the idea for
the whole approach from lengthy listening to old 78 rpm discs dating back
thirty or forty years. To get the right
sonic effect when voicing his own
"lyrics," Stephens obviously spent a good
deal of time in the recording studios
experimenting with mikes and filters.
There is just a suggestion of the megaphone effect we used to get from crooners on old records. The dead -pan delivery
clinches the matter. The rest of the
album offers slightly less effective versions of actual songs of the era that are
C.S.
being spoofed in the main tune.
The New First Family, 1968
Verve 15054
The team of comedy writers responsible for the original First Family album
is taking a somewhat more cautious
course in its latest release. Bob Booker
and George Foster are now aiming their
barbs at an imaginary Washington administration instead of a real one and
using the occasion to crowd in as many
impersonations of show business folk
as one record can hold. Some current
political luminaries come in for their
share of lampooning at the hands of
skilled impersonators but the bulk of
the material deals with prominent entertainers who are brought together to
form a fictitious 1968 administration
headed by Cary Grant. (It seems he was
elected to the nation's highest office because of the way he says "Judy, Judy,
Judy.") The rest of the idea behind
the album is equally farfetched. Five
New York actors imitate a staggering
number of Hollywood and Washington
celebrities. The impersonations range
from average to startling in capturing
the inflection of the original character.
The best job of impersonation may be
so regional that listeners across the
country will not get the full flavor. New
Yorkers, however, will get a kick out of
Dave Frye's impression of William
Buckley, who ran for mayor of the town
in the last election here. Most of the
material is bright and topical but in the
final analysis the record will probably
sink or swim on the strength of the
C.S.
impersonations.
experience in the production of sonic
block busters. The quality of its pressings and the range of its frequency response have been a notch or two below
the industry's best. The label has been
able to get away with fairly haphazard
pressings because its roster of artists has
been primarily vocal talent aimed at the
teen market. Here Fontana is sending a
boy to do a man's job in engineering.
Recording a large band out of doors
is not an easy task. Other labels have
tried it from time to time but few, very
few, have succeeded in emulating Vanguard's truly outstanding engineering performance in the Queen's Salute, taped
way back in 1957. One would think
that tape machines available to Fontana
today could at least match those used
by Vanguard in '57. The use of portable
units by Fontana can not be ruled out
but it doesn't seem likely. Fontana's disc
apparently ran into several difficulties
once the production got under way. The
master tape is not up to snuff and neither
is the pressing. The overall impression
is of sound that is slightly off -mike, an
out -of -focus effect that may be the result of the recording crew's inability
to get their mikes into ideal positions.
Another factor enters the picture but
this one is hardly the fault of Fontana.
The changing of the guard is nowhere
near as exciting a ceremony in sonic
terms as the Queen's Birthday Salute on
the parade grounds of Hyde Park with
its 21 gun salute and clatter of horses
hooves on the hard pavement. In the
area where the two discs can be compared on fairly equal terms-the sound
pickup of the two bands-this new release just doesn't meet its promise. The
musical program by the Scots Band is
a relatively tame one. As for the ceremony, the bulk of it is covered on side
one of the disc with descriptive commentary by Major A.J.R. Harrison
punctuated by the throat-shattering commands of the drill sergeants. Then the
band takes over on side two with a
diversified concert that finds Sibelius and
Mozart rubbing shoulders with comC.S.
posers -for -the -military.
Band of the Scots Guards:
Changing the Guard
Fontana SRF 67558
The full title of this release seems
to have been dreamed up to produce a
gleam in the eye of the typical sound
fan. "The Pageantry and Color of
Changing the Guard" is the legend on
the cover that is spread in bold letters
above the listing of the Scots Guards
Band. The photo shows the band emerging from the courtyard of Buckingham
Palace (the London residence of the
Queen, you know) and immediately one
begins to think of the wonderful sound
we got years ago in the made -in -London
album called The Queen's Birthday
Salute (Vanguard VSD-2011). As it
turns out, the major trouble this album
has lies in the simple fact that the label
says Fontana instead of Vanguard. Fontana, a division of the Mercury family
of record labels, has had little or no
TO OUR
A new post office directive requires
publishers to pre-sort magazine
mailings by 5 -digit zip codes. In
order to ensure the same prompt
delivery of your copy of Audio,
please check the address label from
this issue. If it does not contain
the 5 -digit zip code, please write
it in and mail it back to Audio, 134
N. 13th St., Phila., Pa. 19107.
AUDIO
'52
www.americanradiohistory.com
READERS
FEBRUARY, 1967
Jazz & All That
John Coltrane: Live at the Village Vanguard Again!
Impulse Stereo AS9124
Given the combination of an engineer who is more intent on recording
music than club atmosphere and a serious
group of sophisticated listeners who
know when to remain silent, it is apparently possible to make recordings of
decent quality in a night club. From the
standpoint of technical quality, the present release will stand comparison with
some of the best studio work. Musically,
it is a further adventure in Coltrane's
continuing creative quest for newer
forms and more meaningful expression.
As on the recent Meditations, Pharoah
Sanders is on tenor. Once again, it is
clear that these two men make a splendid
team. Jimmy Garrison, bass, two drummers, Rashied Ali and Emanuel Rahim,
and Trane's wife, Alice, make up the
balance of the group. In the disc's major
opus, a new version of My Favorite
Things that begins on side one with a
five-minute introduction for bass solo
and extends over the entire second side,
Coltrane is heard on bass clarinet in a
lengthy dialogue with Sanders who
switches to flute for this portion of the
main piece. Earlier in the work Sanders
plays tenor against Coltrane's soprano
sax. The other number is Coltrane's
Nainia. Together they make a very moving experience.
B.S.
Archie Shepp: Live in San Francisco
Impulse Stereo AS9118
The past two years have seen substantial development in Shepp's ability
to organize his ideas and present them
in a succinct framework. With this release it becomes clear that Shepp is out
of the young talent department and can
now be considered one of the major
creators of the new jazz. He has achieved
the kind of dynamic balance between
pace and poise that makes possible complete artistic statements instead of the
comments -in -passing that are often interjected into the frenetic rush that characterizes much of the new music. In
addition to his work on tenor, Shepp
demonstrates a fine sense of keyboard
color in his reworking of Oley Speaks'
Sylvia. Roswell Rudd, trombone, Beaver
Harris, drums, and Donald Garrett and
Lewis Worrell, bass, make up the balance of this smoothly functioning group.
Shepp devotes one of the six bands on
this new set to the recitation of his
poem, The Wedding. It is read by its
author to a lovely bass accompaniment
by Worrell.
B.S.
The Jazz Legacy of Bud Powell
Verve Stereo VSPS-34
Ten solos recorded between 1949 and
1956 have been gathered together and
reprocessed in pseudo stereo as a memorial to the great jazz pianist whose
tragic life ended in August 1966. Included are some of the most memorable
AUDIO
FEBRUARY, 1967
Bertram Stanleigh
Powell numbers, such as 'Round Midnight and his own I'll Keep Lovin' You
and Parisienne Thorofare. The spread out sound of this artifically created
stereo results in some rather diffused
vocal sound when Powell hums as he
plays, but the brisk fingerwork comes
through cleanly, and the accompanying
bass and drums are unblurred. George
Duvivier, Percy Heath, and Ray Brown
alternate on bass, and the drummers
include Art Taylor, Max Roach, Osie
Johnson. and Kenny Clarke.
B.S.
Ella Fitzgerald: Whisper Not
Verve Stereo V6-4071
Consistency is one of the hallmarks
of Ella Fitzgerald's familiar style. Everything she touches is transformed into
first class material by her unerring sense
of expression, tempo, rhythm, mood, inflexion, inuendo, and what have you. No
Ella platter is ever less than superb, and
the fact that there are a couple of dozen
discs by this great lady that are just
as good as the present offering shouldn't
deter anyone from acquiring this beauty.
A full dozen numbers includes such
varied fare as Sweet Georgia Brown,
Whisper Not, I Said No, Thanks for the
Memory, Spring Can Really Hang You
Up the Most, Old MacDonald, Time
After Time, You've Changed, I've Got
Your Number, Lover Man, Wives and
Lovers, and Matchmaker. The recording
is as fine as can be hoped for, and the
rather large band under Marty Paich includes some of the best sidemen in the
business.
B.S.
Stan Getz and Laurindo Almeida
Verve Stereo V6-8665
This album represents one of those
rare instances when the whole is greater
than the sum of its parts. It has been
years since Getz has done anything this
good, and Almeida, for all of his Brazilian origin, has never before shown such
mastery of his native style. The rest of
the group is dedicated to supplying
rhythmic support. It is made up of
George Duvivier, bass, Edison Machado,
Jose Soorez and Dave Bailey, drums, and
Luiz Parga and Jose Paulo, Latin percussion. The recorded balance places
Getz and Almeida smack in the center
with lots of crisp percussion emerging
from each side. Everything is bright.
alert, and relaxed. But relaxed certainly
doesn't mean listless in any sense. It's
all very free, lithe, and supple.
B.S.
Willie Bobo: Feelin' So Good
Verve Stereo V6-8669
With his third Verve album, Willie
appears to have graduated from the
status of first among equals that is
normally accorded the leader of a jazz
group and has stepped into the position
of a pop star whose eminence makes
any mention of his collaborators unnecessary. At least one might gather that
idea from the jacket and label copy.
From the music one can only conclude
that Bobo is still playing the same kind
of Latin jazz that was so welcome on
his earlier discs and that adds so much
color when he turns up in the percussion section of someone else's combo.
This time he contributes a couple of
pleasant vocals, one in Spanish, titled
Dichoso, the other, in English, is Lennon
and McCartney's Yesterday. Another innovation is the addition of a small studio
audience to help "simulate the excitement
of a live dance hall on this record date."
Much as I deplore audience noise in live
recordings, I must admit that when the
sounds are deliberately incorporated into
a performance, they are a legitimate
effect, and Bobo has utilized them tastefully. I do hope; however, that such
studio audience sounds do not set a
trend. For all of their anonymity on the
jacket, Bobo's companions on this new
release sound very much like the nine
men on Uno, Dos, Tres, and the sound
on this new platter is almost as good as
that on the earlier winner.
B.S.
Kai Winding: More
Brass
Verve Stereo V6-8657
A very baroque sounding introduction
for solo harpsichord to September Song
startled me into thinking that I had a
wrong pressing. When a vocal group
introdced the melody, I knew I had the
right disc, even if it was very different
from the kind of sound I had anticipated.
This is a very far cry from Kai's recent
Dirty Dog. That offering had four trombones; the present set has seven plus
two bass trombones, guitar, bass, drums,
tympani, bongos, two pianos alternating
with two harpsichords, and the previously
mentioned clutch of vocalists. Arrangements for this combination can be a bit
tricky, and as a result this release turns
out to be a showcase for its six arrangers, rather than for its performers.
September Song and Walk on the Wild
Side are Oliver Nelson arrangements.
Wayne Andre contributes versions of
Laura and l'm Getting Sentimental Over
You, Dick Lieb offers Star Dust, Stella
By Starlight, and Strange. Claus Ogerman sets More (from Mondo Cane) and
Harper; Invitation is a Bobby Scott arrangement, and It's All Right With Me
is heard in Winding's own version. B.S.
Tim Buckley
Elektra Stereo EKS 74004
A folk-rock singer -guitarist with a rich
repertory of original compositions whose
lyrics are filled with colorful imagery,
Buckley is capable of a wide range of
expression, and his vocal delivery is
notable for its immaculate enunciation.
His accompaniments consist of a strongly rhythmic guitar, bass, keyboard, and
percussion group. In several cases, these
forces are superimposed on a string section playing a long, sustained line. The
effect is particularly suited to the material Buckley has written. The sound
has the bright, forward quality that we
expect from Elektra.
B.S.
53
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on anybody's bookshelf...
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ung
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sandwiched in skin -thin aluminum. They respond with piston -like precision to the wave
form of the voice coil signals. The rigidity of
the Sandwich cone eliminates "cone breakup," the erratic flexing which causes distortion in other speakers.
Both Leak Sandwich speakers are flawlessly
balanced systems. Electronic components and
cabinet, materials and structural features are
all functionally determined and integrated.
The rich -grained Scandinavian woods and the
changeable grille cloth are chosen not only
with an eye to beauty but an ear to acoustical
perfection.
Result: a remarkably smooth frequency response, free from violent peaks or troughs,
over a very broad frequency band. Transient
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And the performance of the new shelf -size
Mini -Sandwich is indistinguishable from that
of the larger model except in the lowest
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If space permits, there is only one choice:
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Write for literature on Leak Sandwich
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Dept. A-2
The Perils of Tape Splicing-(0r) The Operation Was Successful But The Patient Died
One of
the games movie -buffs play
called-Spot the Editor's Blunders.
Girl enters dressed in dark suit, camera
pans in for close-up of head, long shot
is
follows, girl now wearing light suit.
Errors like this happen in the best of
studios. Less easy to detect are variations
in mood, background, and other subtle
differences from shot to shot. Example:
Two men arguing, first man facing
cameras; switch to new angle, first man's
back now to camera, dialogue continues
uninterrupted. Suddenly we are aware
that something odd has happened; the
first man's body has gone slack, he is no
longer leaning forward, and his arms,
previously stiff with anger, hang relaxed
at his sides. Obviously this is an inserted shot which the director hadn't
bothered to check out carefully and
which escaped the notice of the film
editor. Drama critic Walter Kerr's description of a voice -view mismatch in
The Night of the Iguana bears on all
such examples of the faulty editing:
.
.
illusion jars to a stop as though
someone had pulled the emergency cord
on a subway train."
Faulty editing in recordings of concert and operatic music is a more elusive
affair. On screen, angles shift continually; in recording, our perspective remains,
or ought to remain, the same throughout
the work. However, a tape mismatch
can be as jarring as its film counterpart.
If you never have been aware of tape
splicing, don't read this article. You
will begin to hear all sorts of things
that may spoil your enjoyment of records. But if you must go on reading,
here are some of the defects you probably will run across.
To the untrained ear, the most obtape bloopers involve outright
mutilation of the score: the splice point
occurs in the middle of a passage of
sixteenth -note runs. In cutting from one
take to another, the editor inadvertently
has snipped off part of the outgoing take,
or cut too late into the incoming take.
The result: a tiny part of a sixteenth
note is missing from the edited tape.
The visual equivalent of such an error
is the skipping of frames in a moving
picture.
vious
Another flagrant case of poor splicing,
probably the most common, is the
acoustical mismatch. This defect occurs
frequently in the recording of operas
and oratorios, where for economic reasons, sessions are planned so that numbers with chorus are recorded on certain days; recitatives with bass and
harpsichord accompaniment, and arias
and ensembles with full orchestral background, on other days. In piecing together the various numbers, the editor
often finds that the recording producer
had neglected to call for an "overlap,"
the few measures preceding the movement to be recorded. Without this overlap, the decay of the preceding music
is missing from the opening bars of the
number following; the notes are all
ERCONA CORPORATION
432 Park Avenue S., N.Y., N.Y. 10016
(212)
LE
2.6560
Check No. 83 on Reader Service Card.
AUDIO
FEBRUARY, 1967
11,n1
IIJI
J
JL
FROM SWEDEN
there, but not the overhang. The dropout of background may last no more
than a fraction of a second, but it is
almost as conspicuous as the "beep beep" of the television censor at a
particularly ribald moment of the Johnny
Carson Show.
Dead space, tape recording's zone of
silence, is present in some recordings for
a more prosaic reason: the tape join is
imperfect. Either the editor has not
quite brought the butts together or -the
tape has stretched away from the splice
point on both sides of the cut because
the adhesive coating of the splicing tape
contained too much liquid. Adhesive
"bleeding" also contaminates other parts
of the reel by pulling away the iron oxide particles of neighboring layers of
tape which is why partial drop -outs often
crop up around poor joins.
Any amateur can learn to perform
the basic steps in tape editing. But it
takes a trained musician to edit the tapes
of a musical performance and come up
with a master that is completely free of
the many kinds of subtle musical distortions that still turn up in classical
recordings, despite the advances in other
aspects of the art of recording.
If the defects are that subtle, are they
really worth examining? It is a wellknown fact that a skillful and sensitive
editor can always produce better results with the same set of unedited reels
than a non-musical editor. The latter
may emerge from his editing room with
a master containing not a single dropout, snip, bump or skip; in fact, you
can't hear the splices at all. But the
tape could still fall short of the mark.
Recently I heard a recording that
could be used as an object lesson in
how not to edit tape. To the casual
ear, nothing would have sounded wrong;
but careful listening revealed all the
telltale seams of an inept assemblage
of takes. The editor obviously had been
handed a pile of tapes containing numerous re -takes of movements and parts
of movements; and the variations in
tempo, balance, and intensity were incredible.
Conductors have been known to
change tempo in midstream, but no conductor could have brought about, or
would have wanted to bring about, the
instantaneous changes in speed, volume
and instrumental balance that were present in this recording. Tempos shifted
gears in mid -phrase, over-all levels rose
and fell, and instrumental lines seemed
to pop out of nowhere and then disappear.
Even if you couldn't spot all the
editing faults, you probably would be
aware that this recording has a cool
impersonal quality. Maybe the performance was to blame. But the unedited
tapes might have contained first-class
material which the tape editor assembled
poorly. At the recording session, perhaps the conductor listened to playbacks
with the recording director and chose
the preferred takes for the final montage:
"Use the second take for bars one
through twenty-four, the first till bar
forty-eight, and the fifth for the rest of
the introduction." Now each take by
itself might have been technically and
musically excellent, but could the takes
be pieced together exactly as the conductor outlines? Would the tempos
match? And what about the intensity;
would the music lead smoothly from one
splice to the next?
Obviously it is dangerous to make the
final editing decision at the session. Each
segment of tape in an edited reel may
be free of defects, have the conductor's
stamp of approval, and still fail the ultimate test.
The first thing a competent editor
must do is to select the best over-all
performance after hearing and re -hearing
each take. If he is lucky, the producer
will have captured the work on tape in
one flawless take. Recordists call this the
basic take; that is, when both the notes
and spirit are present. Having isolated
the basic take, the next job is to replace
obvious blemishes with perfect retakes;
the horn clinker, the cracked oboe note,
the buried inner voice to be brought out,
the imperfect ensemble in an a tempo
bar, or the extraneous noises that plague
recordings made on location in concert
halls, churches, and other rooms not
originally designed for recording.
If this was all a tape editor did, you
would have the right to call him a musical cosmetician. However, his job is
to help the conductor and the recording
director achieve the flow, clarity, and
expression which will make the finished
recording not only a faithful representation in sound of the musical score, but
a performance of integrity and conviction.
I am not going to discuss the question of whether an edited tape is preferable to a "straight" performance. That
is a subject in itself. But if edit you
must, make sure you know how to put
the musical body together again after
you've dismembered it.
Æ
At $400
this would be
a great little
microphone.
At $99.50
it's a great
big miracle.
If you had $400 to blow on a new
microphone, you'd expect the
moon: a professional-quality con-
denser mike with "field effect
transistors," the finest of printed
circuitry, solid state at its solid best
... to upgrade your system to top
recording studio standards of
realism.
Now you can have all of that for far less
in the new PML 71 Series Micro -Minia-
ture Condenser Microphones. Performance? Superb signal-to-noise ratio. High
sensitivity. A linear frequency response
of 40 Hz to 18 kHz ± 3 db. Selectable
output impedance: 30/50, 200 or 600 S2
balanced or HI -Z unbalanced.
In a word, you get 1'/a ounces of PML
Micro -Miniature magic ... and the price
is a third to a fifth of what you might
reasonably expect.
MICROPHONES
$109.50
Cardioid (15 db rejectivity) EC71
$ 99.50
Omni -Directional EK71
(Microphones supplied with stand adaptor
and 12 ft. cable to power supply)
POWER SUPPLIES
7140S
7130
7130S
Battery Operated, Stereo/Mono
with two 12 ft. signal cables
A.C. (110/125v), Mono
with one 12 ft. signal cable
A.C. (110/125v), Stereo/ Mono
with two 12 ft. signal cables
$49.50
$69.50
$89.50
Microphones, power supply and signal cables
are all fitted with locking connectors.
At your dealer or write exclusive U.S. representative:
ERCONA CORPORATION A-2
432 Park Ave South, New York 10016 (212) LE 2-6560
AUDIO
FEBRUARY, 1967
Check No. 83 on Reader Service Card.
Equipment
Profile
SOLID-STATE KNIGHT-KITSKG-895 INTEGRATED AMPLIFIER
KG -790 AM -FM TUNER
Fig. 1. The Knight
Kit KG 790 tuner
shown in its op-
-
Those who have followed the kit market cannot help but notice the increasingly higher quality of recent models. In
the case of Knight -Kits, the introduction
of the KG -415 Tape Recorder was a
turning point-no one will deny that the
electronics of the 415 are excellent, and
the combination of the established Viking transport with the well -designed
electronic chassis results in a great in-
strument.
We mention the 415 because of the
similarity of some of the elements of
it with those of the KG -895, since the
preamps in the latter appear to be identical to those in the recorder. Further-
more, the over-all apeparance of the
panels of the recorder and the amplifier
are sufficiently similar as to make them
an ideal matching combination. The KG 790 tuner panel is a perfect match for
the amplifier-same size, same design,
and same type of knobs. If we sound
enthusiastic over these units, it is because we are.
The KG -790 Tuner
Of the two units, the tuner is the easier
to construct because the entire FM-frontend-and-i.f. section is completely factory wired, and simply mounts in a cutout
on the chassis. The builder has only to
construct the AM section. the multiplex
section, and the chassis wiring. and
the job is complete. The instructions are
superbly detailed and we found absolutely no errors in them, nor did we
find any steps which we would consider
o
tional walnut enclosure.
out of order to make the job easier
to complete. This is in itself unusual, and
of course the ideal condition, for kits
are designed not for the experienced
builder, but for the novice, and while
an experienced builder might have no
trouble even if there were errors or out of -order steps, it is likely to frighten the
novice if he finds some step difficult or
almost impossible.
The circuit employs 22 transistors and
13 diodes, three of the latter in the
power supply section. Both AM and FM
sections have r.f. amplifiers, and four
i.f. stages are used for FM, only two
being required for AM. In the FM circuit, a.g.c. voltage is fed to the r.f. amplifier from the first i.f. stage, and a.f.c.
is provided by a d.c. feedback loop from
the ratio detector to the oscillator in the
front end. The multiplex section is reasonably conventional for a solid-state
tuner, except that the switching of the
19 -kHz doubler is effected by a pair of
transistors actuated by the a.g.c. voltage.
Thus unless there is adequate signal, the
set remains in the mono mode; not only
does the 19-kHz pilot signal have to be
present, but the over-all signal level
(A) FREQUENCY RESPONSE - 1 WATT
10
20
o
(B) POWER
R E SP
o N SE
-0 dB
=
40 W
3
2
3
8
100
1000
10000
100,000
FREQUENCY IN HZ
Fig. 2. The Knight -Kit KG -895
amplifier's power and normal -listening -level response.
has to be at a preset value. The 38 -kHz
switching signal is derived directly from
the pilot through a doubler, and no 38 kHz oscillator is employed. Two other
transistors are used in the muting circuit,
and in the presence of a low level of
signal, they cut off the collector voltage
supply to the last i.f. stage and the first
multiplex stage. These muting transistors
are controlled by the third i.f. stage.
In this circuit, all of the i.f. stages act
as limiters, and consequently there is a
control voltage available from any one
of them. The muting level is settable by
a panel control, and one panel -mounted
switch controls a.f.c.. while another
switches in or out the SCA filter. One
additional transistor is used for turning
on the stereo indicator light, and separate output stages are provided for the
right and left channels, of course.
Two outputs are provided for each
channel-one for the normal amplifier
input and one for a tape recorder. In
addition to separate level controls for
the two output channels, there is another level -set control for AM. A rotary
function switch with four positions-off.
AM, FM, FM Stereo controls the circuitry and indicator lights show which
position it is in.
In performance, the KG -790 leaves
little to be desired. Its IHF usable sensitivity is approximately 2.5 µV, with
i.f. rejection of greater than 80 dB, and
AM rejection of 37 dB. Audio output
measured approximately 1.0 V, both on
AM and FM. AM sensitivity for 20 dB
quieting measured at 3.4 µV. Both circuits are relatively wide -band, and the
10 -kHz rejection filter in the AM side
is needed because of the response. FM
i.f. bandwidth is about 300 kHz at 6
dB down, and the detector bandwidth,
peak to peak, is slightly over 600 kHz.
Stereo separation measured 43 dB, and
19- and 38 -kHz suppression was better
than 50 dB.
AUDIO
56
www.americanradiohistory.com
FEBRUARY, 1967
Fig. 3. A
topside
view of the KG
895 showing the
circuit layout. The
preamp circuit
A
TR-1IL
TR -12 L
boards and power
supply are evident.
The lower right
corner shows the
array of heat sinks
that hold the pow er transistors.
TR -9 L (LOWER)
TR-10L(UPPER)
Construction
As previously noted, construction
is
relatively simple. Both the multiplex
section and the AM tuner are constructed
on printed -circuit boards, and the chassis
is well laid out and easy to wire. One
innovation is the use of Nylon cable
clamps (which we first saw in the KG 415) that keep the wiring neat and almost professional in appearance. As
there is no alignment of the FM front
end or the i.f. strip, getting the tuner
in operation is a cinch. The AM section
aligns quite simply, requiring only the
adjustment of one coil and three trimmers to ensure dial calibration. There
are four coil adjustments and one potentiometer setting in the multiplex section, and these are aided by a test switch.
Sliding the switch to position "A" enables one to adjust two coils for maximum indication on the tuning meter,
showing the correct alignment of the
19 -kHz circuits; then with the switch in
the "B" position, two other coils are
similarly adjusted, still using the tuning
meter for indication of optimum setting.
The potentiometer is then adjusted on a
stereo station so that the indicator light
just goes on. This should be done on a
station of medium signal strength.
On the whole, this tuner represents a
good value at $139.95. Another $19.95
gets you an oiled -walnut wood case.
total of 120 watts music power-40 -watts
continuous sine -wave power output per
channel, and all for $149.95.
Referring to Fig. 4, across the top are
the balance control, dual concentric
bass and treble tone controls, the six
indicator-light windows, level control,
loudness switch, and selector-a six position switch with no stops so it can be
rotated continuously. On the lower row
are the phone jack, speaker on/off switch,
remote/main speaker switch, stereo/mono
switch, power switch, channel reverse
switch, hi -cut and lo -cut switches, and
the tape monitor switch. The phase reversing switch is on the rear apron, and
on the input panel on the rear are separate input level -set controls, one for each
channel on phono, tuner, and the aux
inputs. Also provided are two convenience outlets, normally with one switched
and one "hot" although instructions are
KG -415) followed by a driver panel on
which are five more transistors per channel. Four power transistors per channel are used in the output stages, with
each pair on a separate heat sink. These
sinks are mounted over appropriate openings in the chassis for ventilation. The
output circuit is similar to that used previously in Knight -Kit amplifiers, and uses
a transformer between the driver and
output stages. One half of each output
stage is positive with respect to ground
and the other half is negative, the junction between them being essentially at
0 potential for d.c., but at the speaker
signal level for a.c. There are no output
coupling capacitors, (which introduce a
comparatively high impedance in series
with the speakers at low frequencies),
but instead are two 2 -amp. circuit breakers, one in each channel. In case of a
shorted speaker line, or a too -great signal, these circuit breakers open up for
about three seconds and then close again.
If the short still exists, or if the high
signal is still present, the breakers will
open again. We have kept them opening
and closing for several minutes with no
apparent damage, both with the speaker
line shorted (accidentally, we admit)
and with an excessive signal level.
The loudness -control circuit is interesting in that it permits the user to set it
at 5, 10, or 15 dB below normal high
listening level when it is desired to listen
continually to the lower levels. Thus the
degree of compensation is not dependent
on the setting of the volume control, but
only on the setting of the loudness
switch. This is a desirable feature, in
our opinion, because the user is likely
to listen for a long period at the lower
level-such as late at night-and would
want everything compensated for the
lower level, rather than being dependent
on the volume -control setting.
In performance, the KG -895 is consistent. It doesn't make much difference
whether both channels are putting out
Fig. 4. The Knight Kit KG 895 Inte-
Amplifier
grated
shown in its optional walnut enclosure.
The KG -895 Integrated Amplifier
Here is a kit amplifier which includes
most of the features usually found only
on the more elaborate factory -built units
-illuminated windows to indicate the
signal source, loudness control of the
contour-switch type, speaker switch which
cuts off all speakers for headphone listening, remote/main speaker switch, high cut and to -cut filter switches, tape monitor switch, and even a speaker reversing switch for one channel to correct phasing. And with all of this, a
AUDIO
FEBRUARY, 1967
given for making a simple change which
will make both receptacles hot. Separate
input pin jacks are furnished for feeding
a recorder and accepting its output wired
to the monitor switch.
The unit employs a total of 26 transistors-eight of them power types-and
eight diodes. Input switching and equalization changing take place around the
input module, which consists of three
transistors (the same module as in the
the maximum signal or only one-the
distortion remains about the same. With
both channels fully driven, the power
output per channel is about 1 dB less
than with only one channel operating.
The half-power points are at 9 Hz and
65 kHz, which is excellent. Frequency
and power response are shown in Fig.
2, the former at 1 watt. Both channels
measured within l dB of each other,
in high-level and low-level positions,
57
with volume -control tracking within 2
dB throughout (to -40 dB). Loudness control bass boost measured 3, 51/2, and
7 dB at 50 Hz for the +5, +10, and
+15 settings of the switch. Specifications claim a harmonic distortion of 0.7
per cent at 40 watts output with both
channels operating. This figure was met
easily, and the figure remained at that
value down to about 10 watts, then lowered to 0.5 per cent at 1 watt. IM distortion 0.9 per cent at 40 watts output
per channel, with both channels operat-
Fig. 5. The Shure
V-15 II Stereo cartridge. The two
photos show the
built in "flip -action" stylus guard
in playing or pro-
tecting positions.
ing.
Hum and noise measured 67 dB down
on phono, referred to a 10 -mV input
signal; the high-level inputs ranged between 70 and 75 dB; tape head was 62.
Separation at 1000 Hz was 57 dB, and
the output for a tape recorder was just
over 0.5 volts.
As a general purpose amplifier for
stereo use, the KG -895 offers excellent
value; as a companion for the KG -790
tuner, it is a perfect match. It was not
difficult to build, and from the first time
it was turned on, it worked and tested
as indicated.
Check 1
Shure V-15 II Stereo Cartridge
As phono cartridges get better and
better, we find ourselves with less and
less to say. Perhaps ultimately we will
get to one -sentence reviews. This report is short because we find this new
version of a cartridge we already liked
a significant improvement.
We refer you to James Kogen's articles in November and December 1966
for a complete discussion of the technical development of the V-15íI. The
frequency response and channel separation shown in Fig. 6 is self-explanatory.
LEFT-
5
RIGHT----
-
Q
-
SHURE
1
V-15
-
'
5
I
0
C85 STR 100
1
15
,
-20
.
25
-30
a
Hm
FREQUENCY IN
a
HI
Fig. 6. Frequency response and channe
separation of the Shure V-15 II. The
test record is the CBS STR-100.
20 -kHz resonance that is apparent on
the frequency -response curve and you
come up with a first-class cartridge.
This gives only a hint to the superb
sound that this cartridge extracts from
a disc. The fact is that we are hearing
things more clearly than we have heard
before. And that is what an improved
model is supposed to do.
The biggest audible improvement is on
the higher frequencies. Where the older
cartridge tended to touch a bit of edginess; there is no such case here. The
V -15íI is as sweet as you could want.
That says a lot and it says all that
Check 2
Purchasers of the Shure V-15 II are
entitled to send away for a free 12 -in.
record designed to test the tracking
capabilities of a cartridge. The record
contains a series of musical samples,
instruments selected to display specific
tracking problems. Within each series
there are several bands of progressively
increasing loudness. The object here is
to see if your cartridge will track all
the bands successfully. The design of the
record is such that small tracking errors
will show themselves readily.
Our Shure V-15 II sailed through the
record with near perfection. Of several
other cartridges tried, one other also
did so; some others revealed one or more
slight deficiencies.
We believe that this is an impartial
and valuable tool. With this record, any
number of cartridge faults may be isolated. (And identification is the first step
to cure.) V-15 II owners get the record
free as we said. Non -Shure purchasers
may have the record for $3.95. Order
it directly from Shure Bros., 222 Hartrey
Ave., Chicago, Illinois.
IMC Boxer Fan
Do we have to tell you that even in
this age of cool-running (relatively)
transistor gear, proper ventilation of
audio equipment is necessary?
But this is not always possible. The
demands of decor, particularly when
promoted by the hobbyist's distaff side,
can be quite overwhelming. So the alternative soon becomes some form of
forced -air cooling.
No one has ever discovered a method
for moving air violently without making
some sound. But careful design of the
parameters of blade pitch and motor/
blade balance can make significant
strides over the usual kind of fan. Then
too, the common household fan is simply
more than is needed for discrete cooling.
This Boxer fan from IMC Magnetics
a specific product made to do a
specific job. It will not cool a room;
it's not meant to. But it can be placed
in an enclosed cabinet where it will
exhaust warm air (improving tuner
stability, amplifier power output, and
general component reliability). And it
will do this with a minimum of noise
and vibration. We were frankly surprised at the degree of quietness possible.
is
We do not have proper facilities to
measure the cfm output of the fan. But
it seems to us that it will be quite
sufficient for a hi-fi cabinet or a television set. And installed properly with
the mounting accessories supplied, it will
produce very little noise. In fact our
installation on the back of a Heath
color -TV produces so little sound that
it has proved no problem at all.
Check 3
So are our other measurements:
Dynamic compliance -6.5x10-8 cm/dyne
vertical or lateral.
IM Distortion, CBS-STR111-
+
dB is 1.3
dB is 1.8
+12 dB is 2.5
+15 dB is 4.2
Output-Left channel is 4.2 mV
right channel is 3.8 mV,
referred to 3.54 cm/sec.
+
6
9
per
per
per
per
cent
cent
cent
cent
;
recorded
velocity at 1000 Hz.
These are fine figures. Add to them
a square wave that confirms the above
58
Fig. 7. In addition
to these parts the
accessories in-
with the
Magnetics'
Boxer Fan include
an adhesive strip
cluded
IMC
of sponge -type
rubber.
AUDIO
FEBRUARY, 1967
Alabama
Wiregrass Electronics'
HUNTSVILLE
Wholesalers
Industrial Electronics
MOBILE
Electronics World
SpecialtEyy
NEW ORLEANS
`Boyd-Wonn Hi
DECATUR
Forbes Distributing
DOTHAM
Distributing
:Empire Audio Exchange
-
Lloyd's Hi
Fi
Connecticut
HAMDEN
Co.
Lafayette Radio Electronics
HARTFORD
Belmont Records
MUSCSHOALS CTY
Sound LCity Electronics
Arizona
GLENDALE
WEST HARTFORD
Lafa etto Radio
Electronics
Merritt Electric
NEW HAVEN
PHOENIX
Arizona Hi Fi
Storet.
Govway
Woolcó Dep
Dept. Store
SCOTTSDALE
Empire Audio
Delaware
DOVER
David Dean Smith
Lafayette Radio Electronics
WILMINGTON
Govway Dept. Store
Sloan Camera Center
Wholesale Electronics
Wooco Dept. Store
District of
Columbia
WASHINGTON
TUCSON
Save.Co Dept. Store
Arkansas
PINE BLUFF
Audio Specialists
Electronics
Hi
Electronic
Eletr
Wholesalers
Glens Audio Annex
Raley House of Music
California
ANAHEIM
Florida
Anaheim Electronics
Henry Radio
Save -Co. Dept. Store
White Front
AZUSA
Rancho Sound
B ERKELEY
Cal Hi Fi
Robert E. Lee
CLEARWATER
Stereo City, Inc.
'DAYTONA BEACH
Pacific Electronics
BEVERLY HILLS
White Front
Cal MICHAEL
Cal Hi Fi
CASTRO VALLEY
Audio Emporium
COSTA MESA
White Front
COVINA
Acote -Fern
White Front
CT
WEST
Store
AUGUSTA
N & W Camera
Specialty Distributing Co.
Specialty Distributing Co.
COLUMBUS
:SpeCATURcialty
Yale Rad io Electric
INGLEW
Distributing Co.
DE
Alan's of Atlanta
MACONppalt
Inglewood ElectronIcs f
Olson Electronics
Yy
S
LA MESAri
White Front
LONG BEACH
L. M. Baraus
L
ANGEL
LOS ANGELES
-
-
-:
Bel-AirCamera
Henry Radio
Shelley'. Dept. Store
Shelley s Stero Hi Fl Cantrell
Whisco
WhiteOBE
Front
Ç Ostrun
MOUNTAIN VIEW
Abo Home Electronic Center
Audio Video Forum
Cal HI Fi
NORTH HOLLYWOOD
World Electronics
OAKLAND
Fisher Electronics
White Frnnt
-
Co.
stributing
Co.
ctr
Illinois
CHICAGO
Korvette
MATTESONESON
Korvette
MOLINE
Home Electronics Center.
c/o
s Dept. Store
E. J.
Co.
MORTON
J. orretteOVE
OAKLAWN
Korvette
FORT WAYNE
Fort Wayne Electronics
Greiner's
Home Electronics Center
INDIANAPOLIS
Communications Eqpt. Co.
Graham Electronics
Van Sickle Radio Supply
LAFAYETTE
Lafayette Radio Supply
orayye E
MUNC
Muncie Electronics Supply
P ro -Am Electronics
Save -Co. Dept. Store
Iowa
ETTENDORF
White Front
SAN FRANCISCO
B
Home Electronics Canter.
Arlan's Dept. Store
DAVEoNPORT
Griggs Plano Co.
Eber Electronics
Fisher Electronics
Pacific Electronics
White Front
SAN JOSE
Alto Paramount Electronics
White Front
SAN LEANDRO
Fedda's TV
SANTA ANA
WICHITA
Sound Merchandisers
Acorn.Gem Electronics
ÁcoHo
CLARA
Electronic Center
SANTA MARIA
Lombard's Electronics
SUNNYVALE
White Front
TORRANCE
Save -Co. Dept. Store
White Front
LAWRENCE
Fred E. Sutton & Co.
Kentucky
LOUISVILLE
Hi Fi Sales & Service
Louisiana
ALEXANDRIA
House of Electronics
BATON ROUGE
Lafayette Radio Electroniet
Korvette
Lafayette Radio
Meteco ElectronIcs
E. J.
Korvette
FARMINGDALE
Gem Electronics
FOREST HILLS
Gem Electronics
Howard High Fidelity
E. J.
Korvette
GLENS FALLS
Seiden Sound
GREAT NECK
Gem Electronics
HEMPSTEAD
Newmark & Lewis
HUNTINGTON
Gem Electronics
HUNTINGTON STATION
E. J.
Korvette
Rite Electronics
ITHACA
Dryden Radio
JAMAICA
Classic Electronics
Lafayette Radio
JAMESTOWN
Warren Radio
LAWRENCE
Newmark & Lewis
Korvette
Korvette
MONANDS
Gem Electronics
MIDDLETOWN
E. J.
It is excellent
value
SOUTH GATE
These authorized dealers agree. That's why
they recommend it!
Hear for yourself this
fine sounding Wharfedale Speaker System.
It's only $129.95.
MINNEAPOLIS
Audio King
Lew Bonn Co.
Schack Electronics
Sound of the Northwest
ROCHESTER
Lew Bonn Co.
ST. PAUL
B.Z Audio Clinic
Schaak Electronics
Sound of the Northwest
WILLMAR
The Music Store
ONA
Leonard Music
Missouri
JOPLIN
Four State Radio
ST. LOUIS
Korvette
King Sound Co.
SPRINGFIELD
Norman Electronics
E. J.
The Audio Center
MOUNT VERNON
Gem Electronics
NANUET
Korvette
E. J.
Dressner Audio
NEW YORK
Airex Radio
Audio Unlimited
Bryce Appliance
E. J. Korvette
Kooper Products
Harvey Radio
Lafayette Radio
Leonard Radio
Packard Electronics
Rabson's
PELHAM MANOR
E. J. Korvette
PLAINVIEW
Gem Electronics
PORTCHESTER
E.
J.
Korvette
ROCHESTER
Hyatts Hi Fi
ST. JAMES
Gem Electronics
SCARSDALE
Lafayette Radio
SCHENECTADY
Seiden Sound
STATEN ISLAND
E.
J.
Korvette
SYRACUSE
Montana Music Co.
New Jersey
ATLANTIC CITY
Vkld&,dn, Q
University Hill Music
VALLEY STREAM
Gem Electronics
WOODBURY
Yarvey Radio
YONKERS
[Electronics
Electronics
_-
rth Carolina
ers Electronics
EGH
lot Center
orth Dakota
Gem Electronics
M ORES OWN
Don Christ Music Center
NEWARK
Iter?Electronics
EAST ORANGE
Gem Electronics
WEST ORANGE
E. J. Korvette
PARJ.
S
n Electronics
HEBST
hic
Lafayette Radio
Sound Reproduction
E. J.
ension
Stereo
TABULA
Yrren Radio
CANTON
Korvette
Walkeradio
George C. Wille Co.
CINCINNATI
Customcrafters Audio
Hi Fi Audio
The Mytronic Co.
Steinberg's
United Radio
Gem Electronics
Lafayette Radio
Leonard Radio
LafNFte
Lafayette Radio
SPRINGFIELD
DiscoElectronics
GemmElectronics
STEUBENVILLE
Lafayette Radio
TOLEDO
Home Electronics Center,
c/o Aden's Dept. Store
WARREN
Valley HI -Fi Electronics
YOUNGSTOWN
Armies Electronics
Oklahoma
OKLAHOMA CITY
Larsen Music
Oregon
EUGENE
Thompson's
PORTLAND
P
Ivanla
Bitronics
EYNON
Harry Sugermen
ERIE
Warren Radio
HARRISBURG
Harrisburg Radio
KING OF PRUSSIA
E. J. Korvette
KINGSTON
A & B Stereo
MEADVILLE
Walick's Electronics
Warren Radio
PAOU
Hi Fi Center
PHILADELPHIA
Eastern TV
Herman Miller Co.
Sam Goody
John Wanamaker
PITTSBURGH
Lafayette Radio
Radio Parts Co.
Soler Electronics
WEST CHESTER
HI Fidelity Stereo Center
WILKES'BARRE
General Radio & Electronics
WILLOW GROVE
Sounder, Electronics
WYNCOTE
E. J. Korvette
Lafayette
Rhode Island
PAWTUCKET
A
WARWICK
Apex
CHATTANOOGA
Specialty Distributing Co.
KNOXVILLE
Music Land Inc.
NASHVILLE
Nicholson's Hi FI Center
Gem Electronics
Lafayette Radio
Newmark & Lewis
B
Winteradio
NEW HYDE PARK
SYOSSET
Montana
OZEMAN
Rainbow Electronics
ASBURYPARK
Dart Electronics
AUDUBON
E. J. Korvette
BAYONNE
Gem Electronics
E. BRUNSWICK
Gem Electronics
LITTLE NECK
Store
R. A.
HalWI +
BROOKLYN
E. J
Minnesota
ELMHURST
Electronic Supply
Stereo Showcase
White Front
SAN BERNARDINO
White Front
SAN DIEGO
c/o Arlan's Dept.
good
Audioland Men of Music
Home Electronics Center
Allied Radio Corp.
Ralph's Hi-Fi
Distributing
Electronics
It is very
WARREN
EVANSVILLE
George C. Mettle Co.
Home Electronics Center
cs
Korvette
ST. JOSEPH
Indiana
ANDERSON
PLEASANT HILL
White Front
RICHMOND
Pacific Electronics
SACRAMENTO
California Radio TV Supply
New Center Electronics
VALDOSTA
Specialty Distributing Co.
E. J.
PICO RIVERA
Save -Co. Dept Store
MT. CLEMENS
Audioland Men el Music
HomSAGIe
H
Home Electronics Center.
c/o Arlan's Dept. Store
N. RIVERSIDE
E. J. Korvette
SPRINGFIELD
Home Electronics Center
A.orn-Gem
Electronics
Larson Electronics
FLINT
Home Electronics Center,
s Dept. Store
c/o
Homee Electronics Center
GRAND RAPIDS
Home Electronics Center,
/o Adati s Dept. Store
R. L. Karns Electronics
JACKSON
Jackson Photo Center
Puke Photo Center
LINCOLN PARK
Hershel Electronics
MADISON HTS.
Hershel Electronics
SAVANNAH
Norwood's Record Shop
E. J.
It is new
PARMA
ALLENTOWN
Gem Electronics
E. J. Harte
ARDMORE
Sounder, Electronics
BALA CYNWYD
Radio Clinic
BETHLEHEM
E. J.
Michigan
Swartziander Radio
Electronic World
E. J. Korvette
Gem Electronics
Lafayette Radio
CARLE PLACE
Consumer Audionics
FREMONT
HiFi Unlimited
BRONX
Buffalo Audio Center
Purchase Radio
WORCESTER
DAYTON
The Stotts -Friedman Co.
SOUTH EUCLID
BINGHAMPTON
Audio Service
BUFFALO
Lafayette Radio Electronics
SPRINGFIELD
Consumer Audionics
C
istributing
PEORIA
ONTARIO
White Front
OXNARD
Disco Fair
PACOIMA
White Front
PASADENA
mbard's
rd's
eci
Specialty Distributing Co.
ABC PremiumsAcorn-Gem
EI
Fi
B RUNSWICK
HOLLYWOODLL
Hi Fi Corner
LaLombaette
&Hi
Specialty Distributing Co.
Fair
HERMOSA BEACH
H
Sales & Equipment
This is our
model W60C
Home Electronics Center,
e/o Arlan's Dept Store
DETROIT
E. J. Korvette
& M Electronics
Olson Electronics
FRESNO
LE Front
GOLETA
RO
Epco Electronics
BAYSHORE
Gem Electronics
BELLEROSE
Gem Electronics
R. O.
White Front
H
New York
ALBANY
Fort Orange Radio
Seiden Sound
BATAVIA
BAY CITY
Specialty Distributing Co.
L
Art Rempel Sound Supply
ANN ARBOR
Home Appliance Mart
ATLANTA
FY
LAS VEGAS
Stereo Hi Fi House
RENO
SAUGUS
Hershhelel
Korvette
High Fidelity Consultants
CAMBRIDGE
Lechmere Sales
Stereo Designs
DEDHAM
Lechmere Sales
LYNN
Lafayette Radio Electronics
J.
New Mexico
ALBUQUERQUE
Cramer Electronics
DeMambro Hi-Fi Center
Lafayette Radio
Raymond's
World of Music
Hopkins -Smith
JACKSONVILLE
Hoyt High Fidelity Center
STHEN
DOWN
E.
NATICK
Specialty Distributing Co.
COVIOVINA
CULVER CITY
WOODBRIDGE
Massachusetts
BOSTON
Analab
Georgia
ALBANY
Winteradio
E. J.
MANCHESTER
Sound Boo
PENSACOLA
Grice Electronics
SARASOTA
Dow Electronics
TALLAHASSEE
The Sound Shop
WINTER PARK
Frutchey Audio Labs
Korvette
WILLINGBORO
Erikson Electronics
WATCHUNG
American Distributing Co.
Korvette
E.
House
ggJ.
BETHESDAy
McGuires Audio Shop
CUMBERLAND
Radio Parts Co.
GLEN BURNIE
E. J. Korvette
MOUNT RANIER
Lafayette Radio
ROCKVILLE
E. J. Korvette
SALISBURY
Lafayette Radio Electronics
SILVER SPRING
Custom Hi.Fi Music
Massachusetts Camera Ctr.
Electronic Equipmentund Co.
Friedman S
Hopkins -Smith
Sound Center
CAMPBELL
Alco Home Electronic Conte....
CANOGA PARK
Maryland
B ALTIMORE
Certified Electronics
FORT LAUDERDALE
CLEVELAND
Forest City Material Co.
Pioneer Standard Elec.
COLUMBUS
Anderson High Fidelity
Custom Stereo Electronics
E. J.
Custom Audio
Lafayette Radio Electronics
Fi
Colorado
DENVER
Denver Sound Center
Korvette
Georges Stereo Center
House of Hi Fi
TOTOWA
Gem Electronics
TRENTON
METAIRIE
Bell Radio Supply Ce.
VAN NUYS
White Front
VALLEJO
BIRMINGHAM
Likis Stereo Center
ABILENE
R & R Electronics
AMARILLO
Capitol Electronics
R & R Electronics
DALLAS
Crabtree's Wholesale Elec.
Elect romart
FORT WORTH
Audio Distributing
The Fidelity House
HOUSTON
Sound Equipment
LUBBOCK
R & R Electronics
WICHITA FALLS
R & R Electronics
Virginia
BAILEYS CROSSROADS
E. J.
Korvette
FALLS CHURCH
Lafayette Radio
Television Workshop
HAMPTON
GEX Audio Dept.
RICHMOND
Audio Fidelity Corp.
SPRINGFIELD
Capital Recording
VIRGINIA BEACH
GEX Audio Dept.
Washington
BELLEVUE
Vega Trading Co.
SEATTLE
American Mercantile Co.
Lafayette Radio
Standard Records & HI Fi
TACOMA
C & G Electronics
West Virginia
CHARLESTON
Electronic Specialty Co.
WHEELING
Lafayette Radio
Wisconsin
MADISON
Home ElectronIcs Center,
/o Arlan's Dept. Store
MILWAUKEE
Allied Radio
Amateur Electronic Supply
Niebler Electronics
Wisconsin Electronic Supply
The W60C 3 -way bookshelf and floor standing speaker system (dimensions 141/err x
24" x 13" deep) is one of 6 Achromatic
Speaker Systems. Let us send you a free,
full
color comparator brochure. Write
Dept. HB1, Wharfedale Div., British Industries Corp., Westbury, New York 11590.
Check No. 10 on Reader Service Card.
AUDIO
FEBRUARY, 196
59
Tape Guide
HERMAN BURSTEIN
If you have a problem or question
on tape recording, write to Mr. Herman Burstein at AUDIO, 134 North
Thirteenth Street, Philadelphia, Pa.
19107. Please enclose a stamped,
self-addressed envelope. All letters
are answered.
Q. I have been told by a friend that
1 make recordings at 3.75 ips I
when
should turn the treble control of my
hi-fi preamp way up, and when I play
the tape I should turn the treble control
to its normal position. This is supposed
to make the normally higher hiss level
(at 3.75 ips compared with 7.5 ips) less
noticeable. Is this correct?
A. A good modern tape recorder provides adequate treble response at 3.75
ips. In fact, there is often a tendency to
peakiness in the treble range. Following
your friend's advice will get you into
trouble on two counts: (1) You will exaggerate the treble peak. (2) Additional
treble emphasis when recording will
overload the tape, making for excessive
distortion. If, nevertheless, you do follow your friend's advice, then in playback you should turn the treble control
"way down" instead of to normal (flat)
position. I also have a question whether
turning up the treble control of your
hi-fi preamp will emphasize the high frequencies of the signal going into the tape
recorder. Most hi-fi preamps feed the
signal to the tape recorder from a point
ahead of the preamp's tone controls.
In fairness to your friend, I should
mention that some special professional
machines do employ his stratagem, except that a special type of treble boost is
used in recording. Here the treble boost
is mainly in the mid -high frequencies,
around 3000 Hz, where hiss and noise
are most pronounced to the ear. Treble
boost in this region is less apt to raise
the problem of distortion than at higher
frequencies. In playback, the special machines provide corresponding treble cut
in the region around 3000 Hz.
Q. My tape recorder has separate record and playback heads, but not separate
record and playback amplifiers to permit monitoring. I plan to add a tape
playback preamp to permit monitoring.
The tape recorder has two pairs of output
jacks, one pair marked tape amp out,
and one pair marked monitor head. My
hi-fi system preamplifier has a pair of
input jacks marked tape amp, and a
60
pair of jacks marked tape output. The
preamp has a tape -monitor switch. How
shall I connect my tape recorder, the
tape playback preamp, and the hi-fi pre amp so that I can use the tape -monitor
switch for instant monitoring? How does
all this work?
A. Connect the monitor -head output
of the tape recorder to the tape preamp.
Thus the signal travels from the playback head to the monitor -head output
and thence by cable to the tape preamp,
which supplies amplification and equalization. Connect the output of the tape
preamp to the tape -amp input of your
hi-fi preamp. Thus the signal travels by
cable from the tape preamp to the hi-fi
preamp. When you move the tape monitor switch to the tape -playback position, the signal going into the tape -amp
input is connected to the electronics of
the hi-fi preamp, which amplify and
otherwise modify the signal and pass it
to the unit's output, from where it ultimately goes to the power amplifier and
speaker. When you move the tape -monitor switch to the monitor position, the
signal coming into the hi-fi preamp from
a tuner or other source is connected to
the preamp's electronics for amplification,
and so on. The tape -output jacks of the
hi-fi preamp should be connected to the
input jacks of your tape recorder.
Q. I am what you might call an enthusiast about tape recording and would
like to learn as much as possible about
it. Perhaps you could refer me to some
up-to-date literature on the subject. I
am particularly interested in the technical aspects and theory of the recording
and playback processes.
A. You may find the following helpful: W. Earl Stewart, Magnetic Recording Techniques (McGraw-Hill Book
Company, Inc., New York City; $8.50);
Eastman Kodak Company, Some Plain
Talk From Kodak About Sound Recording Tape (Rochester, N. Y.; free;
deals with the magnetic recording and
playback processes as well as with tape);
Herman Burstein, Getting the Most Out
of Your Tape Recorder (John F. Rider,
116 W. 14th St., New York City; $4.25) ;
Herman Burstein and Henry C. Pollak,
Elements of Tape Recorder Circuits
(Gernsback Library, 154 W. 14th St.,
New York City; $2.90).
Q. I have been using a * * * * tape recorder into a * * * * preamplifier. The results have been less than satisfactory.
There seems to be a considerable loss of
signal level and of high frequencies. The
recorder is connected through about 4
feet of standard shielded cable to the
tape input of the preamplifier. Even with
the recorder's playback volume control
near maximum, it is necessary to turn
the preamp volume control much higher
than the setting required for the tuner
and the phonograph. The sound is more
satisfactory when I bypass the preamplifier and power amplifier of my audio
system and connect my speaker directly
to the speaker output of the tape machine. Any suggestion you can make
will be appreciated.
A. There may be a wiring fault in the
tape input of the preamplifier. Check
this by connecting the "preamp output"
of the tape machine to a different highlevel input jack of the preamplifier, such
as the radio input. There may be a fault
in the "preamp output" of the tape recorder. Check this by connecting the
"speaker output" of the recorder to the
preamplifier. There may be a fault in
the cable between the tape machine and
the preamplifier.
Q. I have been wondering whether any
standard procedures exist for measuring
signal-to-noise ratio in tape recorders.
What method is employed by AUDIO for
its PROFILES? As nearly as 1 can determine, most manufacturers' ratings are
based on measurements made with a
signal recorded at such a level as to produce 3 per cent total harmonic distortion on the tape. Since the normal practice is to reduce the maximum record
level approximately 10 dB from the level
corresponding to 3 per cent T.H.D., it
follows that the practical or useful signalto-noise ratio is also reduced by about
10 dB. It would also seem that it is
common practice for manufacturers to
use a weighting network when making
their measurements. The weighting network tends to reduce low- and high frequency noise at the input to the measuring device, while passing the 1000 -Hz
signal at a relatively unattenuated level.
The resulting signal-to-noise ratio is impressive but has little practical significance to me as an individual playing
back tapes through a wide -range repro-
ducing system. In a bulletin on its low noise tapes, the 3M Co. specifies values
for an R -C network to be used in making signal-to-noise measurements. Is this
network to be considered as a standard
one by all parties publishing such measurements?
A. Let me get a breath and I'll try
to answer your complex of questions.
You are right in that most manufacturers of tape recorders, at least high quality ones, base the signal-to-noise
specification upon the recording level
that produces 3 per cent harmonic distortion on the tape. For example, Ampex
and Tandberg do. Sometimes the reference level is the tone on the Ampex
test tape which contains 1 per cent distortion. The difference between the 1 per cent and 3 per cent recording levels
AUDIO
FEBRUARY, 1967
is about 6 to 8 dB. Hence if the signal-
to-noise ratio is stated with respect to
the tone on the test tape, one can add 6
to 8 dB in order to place the ratio on
the basis of 3 per cent distortion. Sometimes the ratio is stated with reference to
the recording level which results in a
0 -VU indication on the recording -level
indicator; this level can be almost anything. In a high -quality machine it is
usually the recording level that produces
1
per cent harmonic distortion on the
tape; so again you can add 6 to 8 dB
to get back to a ratio based on 3 per
cent distortion. I am not sure what the
PROFILE writers do in measuring signal
to noise ratio, and I think you should
query the editor of AUDIO about this. I
haven't done a PROFILE in quite a while,
but when I did I employed 3 per cent
harmonic distortion as the reference
level.
(We use the standard Ampex test tape tone. Ed.)
So far as I know there is no official
standard as to the reference level for
measuring the signal-to-noise ratio at
home speeds, namely 7.5 ips and less.
There is an NAB standard applicable
to professional machines operating at 15
ips or higher. This level is 2 per cent
distortion at 400 Hz.
In any device the signal-to-noise ratio
is based upon maximum level rather
than average level. Thus the ratio of a
power amplifier is usually based upon
maximum power output. Whether the
"practical or useful" ratio of a tape recorder is reduced by 10 dB depends
upon the particular program material.
In some material the average level may
be only 6 dB below the peaks, whereas
in other material the average level may
be as much as 20 dB below. Experience
indicates that if one can keep system
noise at least 55 dB below the peaks of
program material, results are good
enough to be called high fidelity.
I don't know that it is common practice for high-fidelity manufacturers to
use a weighting network when making
signal-to-noise measurements. I know
that such a network is sometimes used,
but I believe it to be the exception
rather than the practice for high-fidelity
components, including tape recorders.
The situation of 3M low -noise tape is
a special one. Here the manufacturer
has been able to concentrate the tape
noise into a portion of the audio spectrum where it is less audible. Although
such tape may in total produce about as
much noise as another tape when measured by instrument on an unweighted
basis, it is preferable to this other tape
if it sounds less noisy. Therefore 3M
prescribes a network so that its lownoise tape will appear to an instrument
more or less as it does to the ear. I do
not know whether this network is one
of several that have been established by
professional societies, nor do I know
whether other tape manufacturers are
using weighting networks in evaluating
tape noise nor whether those others who
do use weighting networks employ the
AUDIO
FEBRUARY. 1967
same one as 3M. This is a query best
answered by 3M.
Q. There seems to be one subject on
which very little has been printed, and
that is the cross-field recording system.
Could you please give me some information on the subject?
A. Information about the cross -field
head can be obtained from Roberts Electronics, Inc., 5920 Bowcroft St., Los Angeles, California, 90016, which uses this
head in some of its tape recorders, and
from the Illinois Institute of Technology,
Chicago, Illinois. In essence, the cross field technique involves the use of a separate head, opposite the record head and
on the other side of the tape, to supply
bias during recording. It is claimed that
bias applied in this way does not result
in as much high -frequency erase as when
bias is applied by the record head.
Classified Order Form
Looking for hard -to -get equipment? Want
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Q. I own a **** tape recorder, which
I have lu d for over a year, but there
are still many recording techniques that
1 still have to learn. I want to make
sound -on -sound recordings, but the tape
recorder manual does not explain this
clearly. Can you instruct me how to do
this step by step? Also echo effect?
A. I don't have a copy of this manual,
but I can outline the basic procedures
for sound on sound and for echo effect.
Assume you wish to record program
material A, B, and C on one track of
the tape in sequence and in synchronization. L denotes the left channel of the
tape machine, and R the right channel.
(1) Record material A through channel
L. (2) Rewind the tape and play back
through channel L; and feed the A signal into a loudspeaker or earphones for
monitoring; at the same time feed this
signal into the input of channel R for
recording. (3) Simultaneously feed material B into the R channel while recording through this channel. (4) Add
program material C by the same process, but this time playing back through
channel R and recording through Channel L. And so forth for additional program material.
For echo effect on, say, Channel L,
simultaneously record and play back
through this channel. Feed the output
signal into the input for Channel L,
along with the material being recorded.
Depending on the input facilities of your
machine, you may or may not need a
Y-connector at the input in order to
accommodate two signals at once. Control the level of the playback signal fed
back to the input by using the playback
gain control for Channel L. Excessive
playback signal will culminate in loud
and unpleasant breakup. The nature of
the echo effect will depend on the
amount of signal fed back, on the tape
speed, and on the spacing between the
record and playback heads. The best
effect will probably be obtained at the
highest tape speed of your machine,
sounding somewhat like the reverberation of a very large and very live hall;
the term cathedral effect is sometimes
used to describe this. At slower speeds
your machine will probably produce a
series of distinctly repeated echoes.
Æ
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Address_
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N. 13th St., Philadelphia, Pa. 19107.)
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1967 Catalog
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61
CASSI1IED
EiOOKSHEL.F
Designing and Building Hi-Fi Furniture
Jeff Markel
Written by a professional
hi-fi furniture designer
Maintaining Hi-Fi Equipment
Joseph Marshall
A valuable reference for
anyone whose living or
hobby is servicing hl -ff
equipment. Outlines the
professional approach for
servicing all types of hi fl components. Covers
trouble -shooting of elec-
who has taught furniture
design at leading colleges, this book is an authentic 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
acoustic
pages.
problems.
224
o. 58 Paperback $2.90'
CH 3-4812
HI-FI SPEAKERS EXPERTLY REPAIRED
USED SPEAKERS BOUGHT
AUDIO SPEAKERS TECHNICS
22 Astor Place, New York, N.Y. 10003
AL 4-2140
decor minded. 224 pages.
No. 79 Paperback $2.90'
SOUND in the THEATRE
Edited by C.
recording, broadcasting, manufacturing and servicing of
components and equipment.
book for the
high fidelity enthusiast. 144
pages.
-
7j
''
-High- _:'. .,-t2--Fidelity H_--(Amplifiers
i
E---..
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.
Written specifically for the
serviceman and audio hobbyist who wants to get into the
profitable field of stereo hi-fi
service. 12 fact -filled chapters with a plain and simple
approach to troubleshooting
all types of stereo and mono
amplifiers-a direct text on
Contains
Easy to read-includes
data on test instruments and
procedures. 128 pages.
ills.
$2.95
wealth of
No.115 $2.50'
Indiana 47941.
LOCATION RECORDING. Sound Rentals for Concerts, Festivals, Conventions,
Condensor Microphones, Wireless Microphone, Theater Speakers, Equalizers,
Stereo. Studio Recording $10 hour with
tuned Steinway Concert Grand. "Abundant Sounds Recording Studio," 6
South Mole, Philadelphia. LOcust 80985.
TAPE
DUPLICATING. Low prices. Any
quantity. G&G Recording Service, Box
412, Peekskill, N. Y. 10566.
EQUIPMENT WANTED
WANTED: Crown
Recorder,
Used. George Stamm, 451
New or
Linden,
Aurora, III. 60505.
-
Save over 35% with this collection of AUDIO books
6th AUDIO ANTHOLOGY ($3.95)
5th AUDIO ANTHOLOGY ($3.50)
McProud HIGH FIDELITY OMNIBOOK ($2.50)
TROUBLESHOOTING HIGH FIDELITY AMPLIFIERS ($2.95)
... $12.90
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CIRCLE 0S500
Total Value All Four Books
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Jones and Associates, Box 142, Dayton,
SAVE
MONTHLY SPECIAL
SAVE
a
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 hi f, furniture. A perfect
guide.
curing both, vacuum tube
and transistorized amplifier
No. 128
$3.95
No. 130
Mannie Horowitz
,
necessary
A
TROUBLESHOOTING High Fidelity Amplifiers
--ROUBLE-
McProud,
of high fidelity: FM STEREO
and TRANSISTORS IN AUDIO
EQUIPMENT. A meaningful
reference for everyone in the
fields of audio engineering,
planning, assembling and
testing sound control instalArticulating sound
lations
control with other elements
Operation
of production
and maintenance of sound
control equipment. Describes
and illustrates 32 specific
problems.
-_SHOOTING
G.
publisher of AUDIO, Includes
articles on the two most significant milestones in the field
auditoriums, concert halls and other large
the
enclosed areas where
source and the audience are
Contains
present together.
complete procedures: For
-
Anthology
The 6th AUDIO
theatres,
SERVICES
HIGH FIDELITY SPEAKERS REPAIRED
AMPRITE SPEAKER SERVICE
168 W. 23rd St., New York, N. Y. 10011
arrangements for the
Harold Burris -Meyer First book of its kind
and
nothing like it has ever been
published before) It is an
Vincent Mallory
authoritative text on electronic sound control for
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advertisements. Rates are net, and no discounts
will be allowed. Copy must be accompanied by
remittance. Closing date is the FIRST of the
second month preceding the date of issue.
This Offer good only on direct order to the Publisher
One Electro Voice 15 WK
sell a 15WK to get a
matched pair of Woofers.
WANTED:
Woofer-or will
FOR SALE
TAPE RECORDER. Roberts 144 or 440,
Sony 200-600 or 777S4, Concertone
S505 -4R, Ampex 4460-Speaker Ampli-
fier 620 or 2012.
AUDIO Bookshelf
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orders
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Please send me the books
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(No C.O.D. or billing.)
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115
120
123
125
126
128
130
142
251
OS500
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ADDRESS
CITY
STATE
ZIP
and
Canadian
postpaid.
Advice condition,
price. T. A. McIntire, Box 3267, Wilmington, N. C. 28401.
TAPE RECORDERS, Hi-Fi components,
Sleep Learning Equipment, tapes. Unusual Values Free Catalog. Dressner,
1523T, Jericho Turnpike, New Hyde
Park, N. Y. 11040.
HARPSICHORD:
Same as owned by
Philadelphia Orchestra and RCA Victor.
In kit form for home workshop assembly, $150. Clavichord kit, $100. Free
brochure. Write: Zuckermann Harpsichords, Dept. R. 115 Christopher St.,
New York, N. Y. 10014.
Classified Opportunities
FOR NEW AND USED COMPONENTS, HI-FI JOBS
AND EXCHANGE OF SERVICES AND SUPPLIES
"CROWN" Professional Recorders: New
and used. Reasonable prices. Wiegand
Audio Labs, 221 Carton, Neptune, N. J.
07753.
DISC RECORDING EQUIPMENT: Cutter and
Recording Amplifiers,
heads,
Lathes. New and used. From Rek-OKut to Scully. Send requirements. Wiegand Audio Labs, 221 Carton, Neptune,
N. J.
07753.
AMPEX 2070 tape deck. Automatic
threading and reversing. Hysteresis
motor. Condition like new, in original
box. New $499.95. Sell $295.00. J. M.
Edelman, M.D., 4550 North Blvd., Baton
Rouge, La. 70806.
ACROSOUND Ultralinear II 60 watt
Pair for stereo,
power amplifier.
$120.00. J. M. Edelman, M.D., 4550
North Blvd., Baton Rouge, La. 70806.
Military Trans-ceiver. Will accept
any reasonable offer. Sgt. J. J. Dacey,
U.S.M.C. 3/3 M -Co., 2nd Plt., FPO San
Francisco, Calif. 96602.
Neuman U-67, Sony
300, Presto cutter, Fisher XP4A's,
J B L 33's plus many more. G Chapekis, 6500 So. Univ. Blvd., Littleton,
Colo.
AMPEX PR -10-2,
Buy a
Monitor.
Visual
Volume
Dynamic
$49.50. Startronics Electronics, Hollywood, Calif. 90028.
DRESS UP your Hi-Fi or Stereo.
AMPEX 351-2 Stereo Tape RecorderLike new condition. $1495.00.
$100.00.
Custom dog house consoles $150.00
each.
Brand new Ampex MX mixer $350.00.
2 Collins limiters 356E-1 and Power
Supply $450.00
EV Microphones -2-666's and 1-655C
$300.00.
2
Altec A-7 Speakers $400.00.
2
Mixing Consoles $200.00.
Collins Mixer $200.00.
1
-
available.
NAME
ADDRESS
CITY
2 Ampex Stereo
ZIP-
STATE
If you have a friend interested in electronics
send his name and address for a FREE sub-
POSITION WANTED
PRC
Sel -sync
Fill in coupon for a FREE One Year Subscription to OLSON ELECTRONICS' Fantastic Value Packed Catalog Unheard of
LOW, LOW PRICES on Brand Name
Speakers, Changers, Tubes, Tools, Stereo
Amps, Tuners, CB, Hi-Fi's, and thousands
of other Electronic Values. Credit plan
scription also.
AIR FORCE VETERAN: Desires job as
High Fidelity Salesman; extensive Practical Knowledge in High Fidelity. ExperiMartin Caulfield,
enced Audiophile.
4026 68th Street, Woodside, N. Y.
11377.
571
S.
Forge Street
Akron, Ohio 44308
Check No. 86 on Reader Service Card.
Our tails are always red...
-
automatically. A 30 inch
Irish tells you which end is up
trailer (always in red) and a 30 inch color -coded leader (never
in red) eliminates tape stretch and wasting tape footage. Write on the leader
you'll
and identify reel contents
never have to worry about putting
a reel back in the wrong box. We
really care about how we make
a tape. Irish is a premium quality
but costs no more. And
tape
there's no charge for the leader,
trailer and reversing strips because we believe every good
tape should have it.
-
-
30" red trailer tells
you it's "the end"
30" color -coded leader.
Write on it and identify
reel contents
Amplifiers $135.00.
Stereo Echo Chamber $70.00.
McIntosh Stereo Tuner MR65B $225.00.
Automatic metal/
reversing strips
C20 Pre -amplifier $185.00.
MC240-$195.00.
2 Monitoring Amplifiers, 2 Filters, Test
Equipment, Jack panels, etc. Would
make a package deal on all equipment. Johnny Price, DA 1-6576,
11819 Lippitt Dr., Dallas, Texas
75218.
"Signature" Book Binding free.
Handsomely identifies box contents.
IRISH MAGNETIC TAPE
458 Broadway, New York,
N. Y.
10013
Check No. 89 on Reader Service Card.
AUDIO
FEBRUARY, 1967
63
Assure 100%
NEW PRODUCTS
COMPLETE
ERASURE
Tope
of Recorded
ON THE REEL
Use the
Magneraser
-tle
dal tCe
Ougtival aud
hew ULTRA -SENSITIVE
FLUTTER METER
With built-in Three-Range
Filter, 3 kc Test Oscillator,
High Gain Preamplifier
and Limiter. Filter Ranges:
0.5 to 6 cps; 0.5 to 250
cps; 5 to 250 cps.
Designed for rapid visual indication of flutter and wow.
Meets standards set by the IEEE
Condensed Specs.:
Input Voltage, 0.001 to 300 Volts; Ranges,
0.01 to 3%; Limiter Range, 20 db.; Oscil-
...
lator (built-in), 3000 cycles; Net Price,
..
Write for complete specifications and free 12 -page booklet on Flutter.
.
AMPLIFIER CORP. cif AMERICA
75 Frost St., Westbury, N. Y.11590
cover that locks to prevent tampering,
the aforementioned phono preamp; a
stacking kit that allows convenient interconnection and stacking of several mixers; and a rack -panel mount kit. List
price of the M68 is $125.00.
CIRCLE XX
Sherwood's newest is AM and FM with
automatic switching to stereo when a
stereo signal is sensed. Silicon transistors are used exclusively. These, combined with a dual AGC system will maintain selectivity under the strongest signal
conditions. A zero -center tuning meter is
used to aid in selecting stations; a front panel volume control permits the tuner
to directly feed a power amplifier. Rocker action switches control automatic
Instrument Pickup
t°iedt!
Quickly erases a reel of magnetic tape or sound film
of any size or type. Erasure is 100% complete even
on severely overloaded tape. Lowers background noise
level of unused tape 3 to 6 db. Also demagnetizes
record -playback and erase heads. Only $24.00. Two Year Guarantee. Available at your dealer's or write us.
$495.00
All Silicon Tuner
(516) 333.9100
Check No. 96 on Reader Service Card.
cpEE
STEREOMONO; AM -FM selection; inter channel hush; and power ON/OFF. Speci-
fications for this model S-2300 are: IHF
FM sensitivity -1.6 µV; typical selectivdB and 820 kHz
ity- 250 kHz at
at -60 dB; AM sensitivity is 2 µV at 60
per cent modulation of a 6 dB s/n and a
4 kHz selectivity at -6dB; stereo separation -35 dB; FM capture ratio-2.2
dB; FM stability-± 10 kHz; FM cross modulation rejection-85 dB; FM distortion-less than 0.25 per cent IM or harmonic at 100 per cent modulation; and
hum and noise in FM is 70 dB below
100 per cent modulation; for AM it is
56 dB below 100 per cent modulation.
Price is $199.50 for the custom -mounted
chassis or $208.00 in a walnut -grained
CIRCLE XX
leatherette case.
-6
STEREO
INFORMATION
station directory
covers FM
stations in U. S. and Canada. Factual
equipment test reports. Test reports
on
tuners, preamps, poweramp/
preamps. Find out what the experts
think. A complete 36 page catalog
tells about tuners, power amplifiers,
preamplifiers, preamp/power amp
combinations, and tuner preamp.
FM
.
ALL FREE
.
.
-
TO:
McIntosh Lab.lnc. 6 Chambers St,
Binghamton, N. Y. 13903
NAME
STREET
STATE
ZIP
The model M68 is the latest product to
carry the Shure Brothers name. It features inputs to accommodate up to four
dynamic or ribbon microphones. These
may be high or low impedance; each
position has a switch -selector. In addition to the four mike inputs the M68 has
a single high-level input. An A68P Phono
JUST WRITE
CITY
Microphone Mixer
-___
Pre -Amp accessory can convert this into
a magnetic or ceramic phono input. Each
of these five channels has its own volume
control. A separate master volume control is also present. Output of switch selected high or low impedance is available to feed the microphone input of a
PA amplifier or tape recorder. A second
high-level output for direct connection to
an amplifier is also provided. Several
accessory items are available. These include a battery power supply; a panel
This interesting device crossed our desk
a while ago and made us stop to take a
second look. The illustration shows one
of these transducers securely mounted in
the mouth of a saxophone. In point of
fact the unit may be used with most
wind or brass instruments and is designed to operate directly into a high quality amplifier. Koss Electronics is the
manufacturer. President John C. Koss
states that the pickup adds full-bodied
drama to tones and actually makes instruments easier to play because the
musician need not blow so hard. Certainly it suggests applications beyond
that. The transducers are available
through music stores.
CIRCLE XX
Slide Rule
Here is a useful tool for the experimenter and construction buff. This Amperex unit provides a dual function.
Check No. 85 on Reader Service Card.
AUDIO
64
www.americanradiohistory.com
FEBRUARY,
1967
First, it gives the circuit designer a quick
means of determining the component
values and transistor types required in
a series of seven basic audio amplifier
circuits ranging from a 1 watt amplifier
to a 5 watt car radio. Merely by moving
the slide you will arrive at the complete
circuit layout from input to speaker. But
the really valuable function of this slide
rule is its use as an audio calculator. If
you know either the value of the load
resistor or the output power, you can
calculate the related values required
within a circuit of complimentary symmetry. The slide rule is priced at 50c
and is only available from Amperex
Electronic Corporation, Semiconductor
and Receiving Tube Division, Hicksville,
Long Island, New York 11802.
MOST UP TO DATE
THE
AUTOMATIC REVERSING STEREO TAPE RECORDER
Industry
Notes
AUTOMATIC REVERSE
Remember CONRAC? They remain, of
course, a well-known manufacturer of
broadcast, industrial, and educational
television equipment. A recent release
announces a new plant of 120,000 airconditioned feet will be used to consolidate all operations under one roof. CON RAC is now spread over six separate locations in the Glendora, California area.
The new plant will provide a 50 per cent
increase in floor space. Can we hope for
a return to the consumer market?
A. W. PRESKILL, v.p. and general marketing manager of ALLIED RADIO has announced the appointment of JULES BRAN DELL as director of advertising for the
Chicago -based corporation. Formerly he
was ALLIED'S mail order manager. In
his new duties he will coordinate the national mail order, industrial, and store
advertising. He will continue to direct
the production of the company catalogs,
direct mail, and other promotional material.
WALT FLIESLER, well-known to us easterners as a representative of several highfidelity manufacturers will now become,
we are sure, equally well-known (and
well -liked) to westerners. WALT has recently moved to San Francisco and
formed ELECTRONIC MARKETING ASSOCIATES. He will initially represent JBL
INTERNATIONAL and BOGEN for the Northern California and Nevada areas.
At the national convention of the National Electronic Associations, held recently in Winston-Salem, N. C., MORRIS
L. FINNEBURGH, SR., chairman of the
board of the FINNEY COMPANY was
awarded a special citation which read:
`In appreciation for the personal time and
efforts expended during the past years as
a speaker of inspiration to thousands -For the interest taken in individuals,
groups, and causes that has given encouragement and hope, and has helped to
bring about a more responsible and high caliber association, and association member. This special citation is presented to
Morris L. Finneburgh, Sr. by the Second
Annual NEA Convention!'
AUDIO
FEBRUARY,
Simple to use and entirely automatic.
Operates by adhesive metal sensing strip.
AUTOMATIC PROGRAMING Program switch provides for single,
dual or repeat tape operation with automatic shut off.
SIX HEADS 2 erase, 2 record, 2 playback. Complete compliment of
first class heads in each direction for professional recording with no
compromise. Uses separate record amplifiers, monitor from tape.
Both recording and playback.
1967
*FREE CATALOG ON REQUEST
Servicing
the
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Dokorder
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IOU
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OTA -KU,
the
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at
-CROME
TOKYO,
JAPAN
oroldr
DENK=
11111)oLAr.
crejx- YO CO..
LT1
.
Check No. 95 on Reader Service Card.
Live Better Electronically With
LAFAYETTE RADIO ELECTRONICS
NEW! MODEL LR -1200T SUPER DELUXE 120 -WATT
SOLID STATE FM/AM STEREO RECEIVER
25995
No Money Down
99-0150WX
*
FREE
1967 CATALOG NO. 670
Over 500 Pages
Everything in Electronics
For Home and Industry from the
"World's Hi-Fi & Electronics Center"
LAFAYETTE Radio ELECTRONICS
Dept. AI -6, P.O. Box 10
Syosset, L.I., N.Y. 11791
NEW! RK 815 SOLID
STATE STEREO
TAPE RECORDER
No Money Down
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r"fl Send me the FREE 1967 LAFAYETTE Catalog 670
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65
Advertising
Index
Acoustic Research, Inc.
Acoustical Mfg. Co.
Allied Radio Corp.
Altec Lansing Corp.
Amplifier Corp. of America
Audio Bookshelf
..
Audio Dynamics Corp.
Upstart
creates a new
concept in sound
systems.
A Young
YL ACOUSTIC CO.,
19
6
61
.
17
Benjamin Electronics Corp.
Bozak
British Industries Corp.
13
23
3, 59
Classified
Crown International
Denki Onkyo
Dynaco, Inc.
.........
62, 63
41
65
15
..
1,
Coy.
specifically engineered to eliminate
one of the major failings of
quality dynamic speaker systems,-narrow band frequency
response, commonly referred
to as "BOX SOUND".
There is absolutely no boom,
which makes for reproduction
of organ pedal tones and other
such program material with a
free sounding NATURALNESS
rarely encountered in the art of
...
....
THE
RECTILINEAR
III
is
a
wide linear frequency response
and dispersion characteristics
are indicative of the meticulous
engineering that has produced
this innovation in speaker design. We believe that our system
is so superior that an actual AB
comparison will support our
claims.
Heath Co.
45
Irish Tape
63
Coy. Ill
FD
-
RECTILINEAR III
$234.50
Size: 35"H x 18"W a 12"D
Hand Rubbed Oiled Walnut
Frequency Response: 22-18,500 Hz±4 db
Impedance: 8 ohms
*
HORN SPEAKER
COMPONENTS
See the March Audio
Magazine for further
details.
Check No. 90 on Reader Service Card.
CANADA
Lafayette Radio
J. B. Lansing Co.
65
21
end Accessories
Marantz Co.
McIntosh Labs.
M racord
Morhan Sales
43
64
13
63
Norelco-AKG
63
Pickering & Co.
Pioneer Electronic Corp.
25
4
Rectilinear Research
Robins Industries
Scott, Inc.
Sherwood Electronic Labs, Inc
Shure Bros. Inc.
Sony Corp. of America
Sony-Superscope, Inc.
Stanton Magnetics Corp.
Coy.
...
Check No. 91 on Reader Service Card.
II
26
7, 51
33
11, 49
31
10
University Sound
47
Rectilinear Sound Systems
Utah
12
A development of Rectilinear Research Corp.,
7116 20th Ave., Brooklyn, N.Y. 11204
Wharfedale
59
Acoustic Co.
SOUND SYSTEMS
126 DUNDAS ST. WEST. TORONTO, CANADA
66
66
Thorens
Y -L
,LECTRO-UO1C E
6
Quad
H. H.
-
5
Olson Electronics
Detailed Specifications available
upon written request.
Listen to it at better dealers or write,
Check No. 93 on Reader Service Card.
YL
High Fidelity Equipment
Complete Lines
Complete Service
HI -Fi Records
Components
8
i
no
-
16
10
3
.
compromise reproducer. Its
!!
IV
14
9
Koss-Rek-O-Kut
i
speaker design.
?
For the ultimate de
mand in sound reproduction,
it's relui red.
YL produces such a tweeter.
Yes
54,55
66
Garrard Sales Co.
J
pound ring magnet for
5
tweeter
10
Fairchild Recording Equip. Corp.
Fisher Radio Corp.
THE RECTILINEAR III is
35
64
62
39
BSR
Electro -Voice, Inc.
..
Elpa Marketing Corp.
EMI/Scope
Empire Scientific Corp.
Ercona
EV Sound Systems
LTD.
66
Check No. 92 on Reader Service Card.
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