null User manual

null  User manual
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'-
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New RCA complements of IOO-milliampere heater tubes for 120-volt series-heater complement ,
bring important sales advantages to your ac-dc radio and phonograph designs.
Slimmer, smaller cabinets-greatly reduced
heat-longer life expectancy-high operating
efficiency!
Now you can design these sales advantages
into ac-dc home radio and stereo, thanks to
a new series of RCA tube complements developed for 120-volts, 1 DO-milliampere
series-heater operation. These are the first
kits of 1DO-milliampere tubes whose heater
voltages add up to 120 volts, the normal
value of power supply that RCA considers
available in most American homes.
With these new tube kits, temperature of
cabinet hot-spots has been cut 15-25 %. This
decrease in temperature permits reduction
of cabinet size (or retention of present size
with cooler operation and better acoustic
response); lessens possibility of cabinet
warping or disco loration; allows wider
choice of cabinet materials; and lends new
flexibility to positioning of parts and printedcircuit boards. And important to you-these
100-milliampere heater tube complements
provide performance equal to that of a 150milliampere heater tube complement;
furthermore little or no modification is required in your basic circuit design.
Get full details on these new 100-milliampere heater tubes! Check with your RCA
Field Representative, or write: Commercial
Engineering, RCA Electron Tube Division,
Harrison, N. J.
. . Th, Mo" T,.."d N,m, in EI,"mni£,
RADIO CORPORATION OF AMERICA
®
NEW 100-MA HEATER TUBE COMPLEMENTS
5-Tube Radio Complement
18F X6 , IRFW6 . 18FY6. 34GDS. and
36A M3-A. Perform a nce equals ISO-MA
heater lube complemen lS' Yet 100-MA
complement dissipates much less heat.
4-Tube Economy Radio Complement
18FX6, 20EQ7, SOFKS. 36AM3 ·A. T o p
performance for a 4-tube complement.
2-Tube Stereo Complement
Two 60FXS 's can provide 1.3 watts output per channel us ing a I,igh-outpul
stereo cartridge.
3-Tube Stereo Complement
20EZ7, two SOFK S's. 20EZ7 permits u sc
of stereo cartr idges w ith moderate output.
4-Tube Stereo Complement
36AM3-A , 20EZ7, two 34GDS's. Capa·
ble o f delivering 1.4 watts per channel
with a B+ supply voltage of 110 volts.
RCA FIELD O FFIC ES
EA ST : 744 Brood St., Newark 2, N. J .
HU 5-3900. M IDW EST: Su;te 1154, Me r·
chandise Mart Plaza, Ch icago 54 , Illinois,
WH 4-2900 . WEST: 6355 East Wash;ngton
Blvd. , los Angeles 22, coni . RA 3·8361.
FEBRUARY, 1961
VOL. 45, No. 2
S.22OO FM/ AM / MX Stereo Tuner-$179.50
Successor to RADIO, E st: 1917.
S-5OOOD Stereo Dual Amplifier-Preamp.
80 Wat~ music po~er ~~l~._~~
ENGINEERING M USIC SOU ND R1: PRODUCTIO N
C. G. McProud, Editor and Publisher
$.2200 - $·3000 m - Sherwood tuners have
consistently won outstanding honors from
most recognized testing organizations. They
feature 0.9!\Uv sensitivity, Interchannel Hush
noise muting system, "Acro·Beam" tuning
eye. cascode balanced input. automatic fre·
quency control. and on the S·3000 m. "Iocaldistant" switch, "Corrective" inverse feedback.
Henry A. Schober, Business Manager
David Saslaw, Managing Editor
Janet M. Durgin, Production Manager
Edgar E. Newman, Circulation Director
5·5000 II-' 'The Sherwood S·5000 • .. shows no
compromise or corner·cutting in design or
construction."-HIGH FIDELITY MAGAZINE.
The Sherwood S-5000 was highest rated by the
American Audio Institute (and other testing
agencies) . . . now even better. the S·5000 II
has 80 watts music power, scratch and rum·
ble filter effective on all inputs. Plus Single/
Dual Bass and Treble Controls. Mid·Range
Presence Rise. Stereo·Mono Function Indicator
Lights. Phase·Reverse Switch, and Damping
Factor Selector.
5·5500-Same as 5·5000 n except 50 watts
music power, no presence rise. $159.50.
Sanford L. Cahn, Advertising Director
West Coast Representativelames C. Galloway
6535 Wilshire Boulevard, Los Angeles 48, Calif.
Midwestern RepresentativeBill Pattis ~ A ssociates
6316 N. Lincoln Ave., Chicagl!- 45, Ill.
CONTENTS
Audioclinic-J oseph Giovanelli
Letters
Light Listening-Chestet· Santon
Audio ETC-E dw(M'd Tatnall Canby
Editor's Review ............................... .
A Case for the Custom Console-F. H. J ac kson
" Ersa tz Stereo" Unlimited-C. H. lJilalmstedt
Computers in Audio Design-R. G. B uscher-In T wo Pa1·ts-Pa1·t One
Character istics of Tape Noi se-William B . S n ow
Tape Guide-Understanding the Tape Oscillator-He1'man BU1'stein and
H em'y C. P ollak · ..... .
Loudspeaker Design-N 01'man H. Crowhu1'st ................... .
Equipment Profile-Sargent-Rayment S R -8000 tune1'-p1'eamp and S R-202
Rev erb emti01~ unit-Shure S tudio Dynetic stet'eo m'm and cart1'idg eF ai1'child 440 tU1"1~ta bl e-H. H. S cott LT-1 0 FM tune1' kit- Ercona N01"Clic
loudspealcer .......... .
Record Revue-Edwa1'd T atnall Canby ........... .................................................... .
About Music-Harold Law1'ence ....
.....................
......... ........................................ .
J azz and All That-Charles A. Robet·tson
New Products
New Literature
Industry Notes
Advertising Index
2
6
8
12
16
18
20
22
New modular component furniture-The serio
ous hi·fi enthusiast will appreciate Sherwood's
new cabinetry in fine hand-rubbed walnut.
Sherwood also makes FM Multiplex Adapters
and Crossover Networks as well as these out·
standing Monophonic units : S·2000 n FM/ AM
Tuner $145 .00 . S·1000 IT "Music Center"
Amplifier·Preamp. 36 watts $109.50.
Sherwood Electronic Laboratories. Inc., 4300
N. California Ave •• Chicago 18, Illinois.
26
28
36
48
60
66
68
74
77
Modular Component Furniture
87
88
COVER PHOTO-Room-divider or wall-type decorator units serve as mounting
for hi-fi equipment. An exclusive creation of Allied Radio Corporation, Chicago,
the line of basic units includes an equipment or r ecord cabinet, shelves and shelf
backguards, and a speaker enclosure which will accept any 12- or 8-in. speaker
and still provide for 30 to 50 LP r ecords. Finish is oiled walnut veneer , with
free-standing satin brass poles drilled every six inches f or complete flexibility in
assembling-and only a screwdriver is needed.
AUDIO (title registered U.S. Pat. Off: ) is published monthly by Radio Magazines. Inc.• Henry A. Schober, President; C. O.
McProud, Secretary. Executive a nd Editorial OIDces, 204 Front St., Mineola, N. Y. Subscription rates - U. S. Possessions,
Canada, and Mexico, $4 00 for one year. $7. 00 for two years, all other countri es, $5 .00 per year. Single copies 50¢.
Printed In U.S.A. at 10 McGovern Ave., Lancaster, Pa. All rl gbts reserved. Entire contents copyrigbted 1961 by Radio
Magazines, Inc. Second Class postage paid at Lancaster. PI.
RADIO MAGAZINES, INC., P. O. Box 629, MINEOLA, N. Y.
Postmastet·: Send FOl'm 3579 to AUDIO, P. O. Box 629, Mineola, N. Y.
AUDIO
•
FEBRUARY, 1961
for brochure write Dept. A·2 .
AUOIOclinic
STABLE
ROTATION
GIVES YOU
REAL
SATISFACTION
NEAT
Professional 4 speed turntable wi t h
P':'68'H
Specifications:
Motor:
4 pole capacitor·sta,,.r:t hysteresis '
synchronous motor. ,
.
Turntable :
12" diameter aluminum diecast·
ing.
Speed:
16-i, 33·i, 45, 78 r.p.m.
Power consumption: 15 watts.
Recomme nded stylus force:
15 gr. maximum
SjN : 45 db minimum
Wow and flutter :
0.25 % maximum
Frequency: 50 cjs.-60 cjs.
Voltage: 90-117 volts.
NEAT ONKYO DENKI CO., LTD.
No. 4· 1 chome , Ka nd a Hi tago·ch o.
Chiyoda ·ku , Tokyo , Japan
2
JOSEPH GIOVANELLI ';'
Head Wear
Q. Quite otten we see tape head man1t·
tacfu1'e1's incl1ule among the'ir specifications
an esti?nated lite tor thei1' heads. For instance, one Viking head has a ?1tini1num
!-ite of 1000 hours acconl'ing to the com·
pany. Si?1.ce no tape speed is specified, isn't
th'is statement incomplete? , It we think of
the wea?'ing prope?·ties ot 1'ec01'cling tape as
consisting of so many "gl-itS per i?fph" ot
weal' at the heaels, then at 3.75 ips it' would
take twic!:: as long to Ca1tSe a given amount
ot weal' than at 7.5 ips. I s this true, or·
have I ovel'looked s01nething? Dick Dun·
ham, Memphis, Tennessee.
A. The data for the life expectancy of a
tape playback or record head must, of ne·
cessit y, be incomplete. The manufacturer
cannot know the speed with which th e
head is to be associated and hence, the num·
bel' of abr asive particles which will pass
over it. Also, he do es not lmow what tape
tensions and pressures the head will be sub·
j ected to.
I would say that tensions and prcs3ures
are more likely to contribnte to t he variat ions in head life than will the possi.ble
variations in tape speed. There is, of
course, no doubt that the f aster tape travel,
the faster the head will wear. However, I
am not at all sure that this wear is directly
propmtional to speed. As the tape speed
increases, there is an accompanying increase
of t he n umber of abrasive particles which
pass over the head during a given time
plus an increase of tape pressure. Obviously, this tape pressure incr ease will re!'u!t in the head being abraded more quickly
t han had th e pressure remained constant.
(You should rememb er, however , that tape
wear does not consist only of the rapid
passage of abrasive particles over tho
head. If these particles passed over the
hEad with zero pressure, there would be no
wear regardless of tape speed. Wear, then,
i~ a combination of the abrasive quality of
the tape plus the pI'essure with which this
abrasion is applied to the head.) Both of
these factors must be taken into account
before we can estimate the life of the head.
With some machines theTe may be no increase in pressure; in othel's the pressure
may increase as the squal'e of the speed
ratios. This depends on the kind of tension·maintaining apparatus the machine
employs.
As you can see, the manufacturer cannot
bike all of this into account. Therefore,
* 3420 Newkil'k Ave., B"ooklyn 3, N .Y.
the best he can do is to give yon an approximation. If one head specifies 100 hours
of life and another one 1000 hours yo u
can guess with some certainty that the lat·
tel' head is a better hea d from the life
expectancy standpoint than the former. We
cannot know, of course, whether this ap·
plies to all other per formance data for the
head.
To Play 78's
Q. I have, in addition to my regular
rec01'd collections, several dozen old 78rpm Tecol'ds elating [l'om the early 30's.
I am planning ·to tape the best ot these.
I wmtld like to know the best 1nethod ot
gett'ing them on the tape. I s it wise to play
the recoTds with a l·mil or a 0.7-mil stylus
in ordm' to get below the wont areas in the
Groove? John Wawzone7c, Cumberland,
Rhode I sland.
A. To begin with, I do not recommend
that you play your old 78's with a I-mil
or a 0.7-mil stylus. Either of these styli
will sink to the bottom of the groove and
will cut into the shellac, resulting in stylus
damage and causing con siderable noise in
reprod uction. FUI:t\ler, the narrow stylns
will flop around ~: the grooves, leading to
poor tracing. .
Your best bet is to use either a 3- or a 2mil stylUS.
Since almost all 78's have no sound above
6000 cps, the·r e is no need for f ull frequency response from your cartridge. Use
a scratch filter set somewhere between 6000
and 9000 cps. If you have a rumble filter,
it should be set to 50 cps. This will give
you the quietest reproduction with little or
no deterioration of the original sound qual·
ity contained on the records. Quieter reproduction could probably be gained if more
of the highs were to be sacrificed, but it is
my personal feeling that a little noise is
not too much of a price to pay for the best
sound.
Noise in Headphones
Q. I have been bothered recently by an
increasing noise level t"om 1ny stereo rec·
ords, especially when played over head·
phones. The noise is a sputtering S01tnd,
present only when the channels are not in
parallel. I t was .negligible in level at first,
but has become objectionable lately. John
Wawsonek, Cumberland, Rhode Island.
A. The sputtering noise of which you
speak can have several causes. First, the
stylus in your cartridge may be wearing
AUDIO
•
FEBRUARY, 1961
...
.....
c
CI
:;:
THE AUTOMATIC TURNTABLE
LABORATORY SERIES TYPE A
MODEL 88 (MK·U)
DELUXE RECORD CHANGER
MODEL 210
DELUXE INTERMIX CHANGER
An entirely new kind of record-playing unit com·
bining all the advantages of a true dynamically
balanced tone arm , a full·size professional turntable , plus the convenience of the world's finest
automatic record·handling mechanism-a ll in one
superb instrument. This unit was designed to
appeal to the most critical and knowledgeable,
with performance so outstanding that it even sur·
passes the professional turntable standards estab·
(Less cartridge) $69. 50.
lished by NARTB.
This is a new version of the famed RC88 manual
player/ automatic changer combination, with every
key feature already proven through years of unsurpassed performance . .. millions of playing hours
in hundreds . of thousands of homes. Now further
refined to provide even better performance, the
new RC88 still offers the exclusive pusher platform
which made its predece ssor the be st selling unit
in the entire high fidelity component field.
(Less cartridge) $59. 50.
Garrard's most compact automatic and manual
changer . . . the Model 210 is noteworthy for its
versati lity . It is scaled to fit any cabinet designed
for a record changer. It plays and intermixes records of all sizes. Though moderately priced, it is
a Garrard in every respect, precision built to
Garrard's highest standards, suitable for the finest
stereo and mono music systems; ideal for replac·
ing obsolete record changers.
(Less cartridge) $44.50.
~ The only dynamically balanced tone arm on
~
an automatic unit. .. with adjustable slid-
ing counterweight, and built·in calibrated scale to set and in·
sure correct sty lus tracking force. Once balanced, this arm will
tra ck ste reo grooves perfectl~ with pre cise specified pressure.
...'"
c:
....=
...~
at
~
Full-sized, heavily weighted (6 lb.). Actually 2 turntables ••. a drive table inside, a non-ferrous heavy
cast table outside; with a vibration·damping reSilient foam ba rrier.
New exclusive, completely shielded 4·pole shaded
>-
Laboratory Series Motor .•. developed by Garrard
especially for the Type A tUrntable system. Insures
true mu sical pitch, clear sustained passages without wow, flutter, or magnetic hum.
.~
~
The great plus feature of automatic play-without
compromise . Garrard's exclusive pusher platform
changing mechanism, makes the Type A fully auto·
matic, at your option. Convenient, reliable, maxi·
mum protection for records .
~
;:::::::::.'
~\
~
Full manual pOSition: The RCBa Is a single record
player as well as an automatic changer. At the
touch of a switch, the tone arm is freed, and
individu al records (or bands) are played by hand.
~
The exclusive Garrard pusher platform-remains the
only automatic device that Insures positive, gentle
handling of all records, rega rdless of diameter or
condition of center hole, or the record surface
or edges .
~
Interchangeable spindles (manual and automatic).
Have no movi ng parts to ni ck or enlarge record
center holes. Records are lifted from turntable
without Interference, with spindle removed.
~
0
Exclusive cast·alumlnum, true·tangent tone arm
provid es ri gi dity . low resonance , low mass. light
weight interchangeable plug·in heads accommodate
cartridges of any make.
~
~
~~
~
~
.,.,..~
~
•
\ \~
~
GARRARD's 4-pole shaded "'nduction Surge n motor
with rotor dynamically balanced-a refinement not
found i n other record changers i n th is class.
Insures constant speed with no hum or vibration .
Extra.sensitive stylus pressure control through in·
stantly accessible knurled knob built into the cast
aluminum tone arm, insures preci se speCified correct tracki ng pressure at all times.
kt\
~
,
Write for your Garrard Comparator Guide, Dept. GB-ll, Garrard Sales Corp., Port Washington, N. Y.
'
" Slide/slide" controls-Select manual (single play)
or automati c operation on separate hal ves of the
unitized panel. Instantly the 210 is ready to play.
Clearest, simplest controls on any reco rd changer!
~
The Ideal Garrard changer to replace obsolete
equipment i n existing cabinets. Every part is
built to Garra rd' s highest standards, yet it is so
compact it will fit any record changer cabinet
You will enjoy a
~.~
I world's finest
for its precision
J... its
~
~~1
performance .•. its convenience •.
\
J
It's the
?~e~()
Sonotone Ceramic ('Velocitone"
No stereo cartridge-not even the finest
magnetic in the world -outperforms it!
Listen! , . with your own magnetic ... or with any magnetic you can buy
today-at any price. Then replace it directly in your component
system with Sonotone's new "VELOCITONE" STEREO CERAMIC
CARTRIDGE ASSEMBLY. Listen again! We challenge you to tell
the difference. Experts have tried ... in dozens of A-B listening
tests. And, in every single one, Sonotone's "VELOCITONE" performed as well as or better than the world's best magnetic.
perfectly flat response in the extreme highs and lows (better
than many of the largest-selling magnetics).
Listen ! , .
'
,
L 1sten.
"
·
, excellent channel separation-sharp, crisp definition. .
. , . highest compliance - considerably superior tracking ability.
L ~sten
'
,
L ~sten
, , , absolutely no magnetic hum - quick, easy, direct attachment
to any magnetic inputs.
.
'
,
L ~sten" , remarkable performance characteristics unexcelled anyWhere,
(Write Sonotone Corporation for specifications.)
Now listen to the price. Only $23.50 Hst ... about half the price
of a good stereo magnetic cartri.dge. Yet Sonotone's
"VELOCITONE" stereo ceramic cartridge system cannot be outperformed by any magnetic-regardless
of price.
and causing an increase in record scratch.
This scratch can be eliminated when the
cartridges are strapped in parallel since
the vertical response is thereby climinated.
Second, it is also possible that there is a
loose connection somewhere in the phono
input circuitry between the cartridge and
the preamplifier.
Much depends on whether the noise is
always present or is present only when a
record is being played. Of course, all tubes
should be checked for shorts and microphonics.
Headphones are always more subject to
noise than speakers are since they are very
sensitive and are directly coupled to the
ear. If you hear this noise with the preamplifier disconnected from the power amplifier, it is almost certain that this noise
i~ generated within the power amplifier and
that the sensitivity of the phones is allowing you to hear it. All you need do in this
event is to reduce the sensitivity of the
phones. This can be done by using an
L-pad between them and the speaker.
Of course, I am only guessing that this
is the method you are using to connect your
phones. You could be connecting them directly to the preamplifier. If this is your
approach, you will still have to reduce the
sensitivity, but it can be done by means
of a series resistor whose value depends
upon the impedance of the phones and
upon the degree of attenuation required.
These are but a few possibilities. Try
them out and see what happens. If you still
have trouble, please write to me. I'll try to
figure out something else.
FM "drift"?
Q. My FM tuner, which does not have
a metal cover, is located in close proxi1nity
to othe7' equipment.
I am troubled by the fact that sometimes
when I walk into the room containing the
tuner, it suddenly goes out of tune. The
degree of this is determined by my posi.
tion in the room. Can you explain this phenomenon and suggest a remedy? Martin
Hack, Kew Gardens, New York.
A. The f act that your tuner does not
have a cover has nothing to do with condition of instability you have noted. What
you are experiencing is not a matter of a
change in turning with certain positions
you occupy in the room, but has to do with
changing signal strengths.
I would guess that you are using an indoor antenna in association with this receiver. Raise this antenna to ceiling height
and place it in a spot where room traffic
is at a minimum. If the final position of
the antenna is near a window, enough signal strength to saturate the limiters will
probably be gained. Once this has been accomplished, you probably can walk all over
the room without noticing these unwanted
signal changes.
Three-W·a y Speaker System Balance
Sonotone"!
ELECTRONIC APPLICATIONS DIVISION,
ELMSFORD, N. Y., DEPT. C26-21
IN CANADA, CONTACT ATLAS RADIO CORP., LTD., TORONTO
Q. I s there not some more exact method
of setting the level controls of a 3 speaker
sound system than just utilizing the way it
sounds to the individ~tal? I have a stereo
sound S1.Jstern terminating in two sets of
(Continued on page 82)
LEADIN G MAKERS OF CARTRIDGES' SPEAKERS' TA PE HEADS' MIKES' ELECTRONIC TUBES' BATTERIES
4
AUDIO
•
FEBRUARY, 1961
Belden has it ...
Every wire and cable you need for
sound and intercom service and installation
Belden Sound and Intercom Cables are designed and engineered for high~st audio
efficiency and quiet performance. These
cables are available in a wide range oHypes,
sizes, and insulations, for all sound and intercom installations. Ask your Belden Electronics Distributor for complete specifications.
Microphone and Shielded Power Supply Cables
~~_
8410
8413
Miniature Broadcast Audio Cable
8411
8420
Two Conductor Shielded Cable
8739
=~~~~=
8761
Three Conductor Shielded Cable
8731
Belden Multiple Pair Individually Sh ielded Cables use
Beldfoil*. a Belden development and a major breakthrough in the search for
quiet cables.
Hp:;f]
Multiple Pair
Unshielded
Cable
8767
•• 1 to 51 pairs
Special Application Cable
i?df??
8734
~8163
power supply cords • cord sets and portable cordage •
.
electrical household cords • mag,net wire •
lead wire • automotive wire and cable • aircraft
wires • welding cable
Hi-Fi Connecting
Cable 8421
AUDIO
•
FEBRUARY, 1961
5
Mystery of the xx's
~nly
s mall
org an with
two full
61-note key·
board s and
22 stops.
Re qu ir es only
2'x3'2" flo o r
s pace ! Comm e rci a l valu e
a pp ro xim ately 51600
or more .
LETTERS
SIR :
Just a line to t hank you for the accurat e
and f ull r evi ew of th e Patrician 700 a nd
Ster eon 200 loudspeakers in your J an ua ry
issue.
.
.
One unfortunat e point of the reVIew IS
th at page 40 has a p a ragraph treating ou
t he size of the P a tricia n but unfortun ately
the meas nrements were never entered be ·
fore going to press. We hop ~ you ca n do
somet hing t o indicate tha t tIns appa rently
dimensionless speaker actu ally does hayc
physical properties as well as eth ereal ones.
W e wa nt to ensure th at your reader s neve r
confuse th e P a trician 700 with t he bookshelf models.
T ER,E NCE E. F UREY,
BUILD THIS SUPERB
ORGAN
FROM SIMPLE KITS
anisave ove,50%
Give Your Family A Lifetime
of Musical Joy With A Magnificent
Schober Electronic Organ!
Now you can build the brilliant, fullrange Schober CONSOLETTE or the
larger CONCERT MODEL with simple
hand t ools ! No skills a re needed ; no woodworking n ecessary. JUst assemble clearly
marked electronic p a r ts guided by stepby-step instruct ions. You build from kits ,
as fast or as slowly as you please ... at
home in your spare time - with a small
table ' serving as your entire work shop.
Pay As You Build!
Start building your organ a t once, invest ing jus t $18.94! The superb instrument
you assemble is as fine , a nd t echnically
perfect, as a commercial organ . . . yet
you save over 50 % on qua lity electronic
parts, high-priced labor, usual store
mar k-up!
Manager, Consumer P r oduct s,
Electro-Voice, Inc.,
Bucha nan, Michiga n.
( How 1'ig h t ! C1Lst01n is t o use xx's inst ead of some in fonnation not iflnmediately
at hand. P1'ope1' additional C1Lst011t is . to
fill in the ,a ppropriate fig ures befo -;e pnn t ing. H erewith the con'ect ed paragraph tor
the pag e 40 omissions :
"Th e complet e Patricia n 700 is not small
by a ny means-obviously .a ny ~nclos~ r~
which can accommoda t e a 30-111. cone
speaker must be la rge. But t he performance
is also "big." The cabinet itself measures
54V2 in. high, -33 in . across th e front, and
28% in. from f r ont to back. , The rear
corner s a re cut off , and the cabinet is intI:nded to be positioned in' a corner with
t he cutoff corners 6 in. from the walls.
Thus the front is 44 in. f rom the actual
earner of th e r oom, measured on the line
bisect in g t he corner."
And we do not have any constnwtion
plans f01' it . ED. )
Mo re Gremlins
Sm:
I ha ve found Mr. Bosselaers' a rticle,
"Designing a transistorized preamp,"
(J anua ry, 1961), both interesting and inform at i ve. However, th er e appear to be
sever al errors which need cor rection. Th ey
are as follows :
Page 26, third columnN
Mail This Coupon For FREE Schober Literature
And Hi-Fi Demonstration Record TODAY!
------------.I
The Schober Organ Corp ., Dept. AE-5
43 West 615t St., Ne w York 23, N. Y.
o P lease send me the 10" hl - U Schober
Il nd other literatu re on the Schober organs.
o Please send me the 10" hl -U Schober
demonstration record. I enclose $2.00 (refundable on receipt or my firs t kit order) .
Name . .. ... . .
fC;
.
II
II
I
I
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6
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el/ should r ead
N
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=\J T
R s = (N - l) 1'e= (N- l )(2/1 e) should r ead
R, = ( N -l) r e= (N - 1 ) (26/ 1e)
Free Booklet
Send for 16-pa ge booklet in full color
describing Schober organ s you may build
f.or home, church or school - plus a r t icles
on how easy it is to build
your c'vn organ and how
THE GREAT
pleasar,t it is to learn to
CONCERT
play. Also available is
10" LP demonstration
MODEL
record (price $2.00 - remee ts
fundable on first order ) .
sp ecification s of
Am e rican
Send for literature. No
Guild of
. obligation and no salesOrganists
m a n will call.
/ 10 V
R .• + I ex 100 ?ll-1i = 680 + 52 x 100 mv = 3-3 mv
2200
2200
R.: +1'0
should read 2200 x 100 111V = etc.
T GR , + 120 11l V = 460 mv should r ead
I eR, + 120 mv = 460 m v .
R , = 6. 6 R, should read R, =6.6 R,
Resistors should have been ma rked on th e
d rawing in Fig. 3. R , is 56k and R . is 9100
in b ase circuit of upper left tra nsistor.
fl.. is 680·ohm r esist or in emitter cir cujt.
i s 680k r esistor from cer amic input. Capacitor valu es associated with th e cer amic
input and wit h the two high· level inputs
should be i u micro·microfar ads (picof a r ads) instead of in far ads as shown .
P age 62, second columnIn th e second li ne, th e equation should r ead
R;
~ - 1) 36,000 = 684,000
( 0.1
In th e appe:ldi x,
7cT (m cos wt-14 nt ' cos 2:JJt)
should be divided by "q".
The last fo rmul a on the page sho uld rea d
qV
1 _ 10 V
tl , k l ' X 4N1 - "Jii'
=
I am also puzzled by t he a utho r '~ high·
fr equency corrections at t he ceramIC and
high-level inputs. H e sta t es th a t R,c.= 7
microseconds ; a nd thus he get s. C = 10 lillCOf a rads for R, = 680,000 ohms. Slllce 7 mIcr oseconds corresponds to about 23,000 cps, I
f ail to see a r eason for ma king R.G = '7
microseconds.
D ON
G.
DA UGHERT Y,
6E Univer sity Houseg.
Madison 5, Wisconsin
( We ag1'ee t hat 23,000 cps seems like too
high a f1'equency to compen sate for, and
we have a sked Mr. Bosselam' f01' f 1Lrtli er
comment. ED . )
More XX's
(It seems as though our fingm' got stuck
on the "X" key during t he preparatton of
t he ,Tanuan / 'iss'ue . On pag e 54, thi1'd co l·
Wlnn, ' fifth -lin e t hey appea1' again. Please
C1'OSS thel1~ onto That's why they, m'e ,there
any71OW--1.Ve, tried to aross O1Lt somet hing
else. ED. )
R.e verberation
SIR :
Will you please a dvise me or print .an
a rticle in r egar d to t he new rever ber atlOll
unit s ~
I am sta rting to convert a r a ther la rge
syst em to ster eo and do not wa nt to slip
up on any possibility. I happen to be a
pipe or O'an fan, and it would certainly
seem th:t of all music t his typ e ,yould be
helped most by such an addition-a r everberation uni t, t ha t is.
G. W . McELHIN NY,
603 Sheth Avenue,
Havre, Montanq a
( See EQUIPMENT PROF ILE , page 48 this
issue, for S01M information on t he newer
1'everb eration unit s. A mm'e c01nplefie m·ttcle is scl!eel'uled f0 1' the April issue; ED. )
Editorial Needs
SIR:
As a r egula r subscr iber of A UDIO, I do
not r emember seeing an article on the can ·
struct ion of a Hi-Fi TV tuner for th e
so und cha nnel only.
Of course, most of us t ake t he so und off
th e TV set. I would like to build a sepa ra t e
tuner fo r TV, since ther e ar e many prog ra ms I li st en to r a ther th an wa t ch (for
example, th e B ell T elephone Hour) .
Can yo u provi de me with a const ruction
a r ticle if th ere is one. If not, perhaps you
can mak e suggestions a nd furnish a block
diag ra m f or such a unit. My thought is to
lise a TV t Ull er unit, cha nge th e oscillator
coils a nd bring th e i.f. to 10.7 mc, and
feeding it into t he FM tun er i.f. st!·ip. Th e
oth er possibility is to use th e F M tuner as
an 88-mc i.f. amplifier.
MOR'l'ON J. S AVADA,
Sunny Ridge Rd .,
H arrison, N . Y .
(Like most invent ions, t he problem is pmct-ieally solved w hen t he need is eletennined.
T he T V t 1Lner f eeding into an i .f . stripand w hy not use a 21-mc i .f.? - is a f airly
simple solution. The 88'1JW i .f. is likely t o
eQ1LSe t1·DtLble with two high·f 1·equency oseillatm's in 'til e same room . We WDtL ld welcome a constrllction article on t his item,
even th01Lgh t he elemand f0 1' 8'1wh a t1L'/Ler
is appm'ently not g1'eat -at least two have
been 01!e1'ecl commercially built, but none
scem s t o be at t he p1·esent. ED. )
AUDIO
•
FEBRUARY, 1961
W
Can that be my Ride of the Valkyries? I wouldn't wish such sound reproduction even on that Italian organ
grinder-Puccini! Now try it through a Pilot 654 stereo receiver. Some difterence. You can hear the rich resonance of
every hoofbeat, the startling clarity of every shriek. The Pilot 654 is the only all-in-one stereo component with a
harmonic distortion factor of only 0.5%. Just hook up a pair of speakers. The 654 supplies the rest: separate FM
and AM tuners, a 60 watt stereo amplifier, and 16 different controls- all on a compact, cool-operating chassis.
~2~~U5~~~::~~;~~I~~ :;~:ea~: :::~~a~:t~ti~~ ~:~~::5:~::~~;n;~~~u~~:
:1I-·9·. _-::_~"
'i.._ _ ~;;. pi.!
e ._;-- .";.
at your authorized Pilot dealer. Both are U.L.-Iisted. Write for literature to: i
Pllor Radio Corporation, 37-38 36th Street, Long Island City 1, N. Y. ;
.~
I"OUNOED 1 81 9
:: Gr:;§~~ e
_:2-;:;:;, # .,~ ,
Gotterdammerung I ..
!
j
AUDIO
•
FEBRUARY, 1961
7
Gets in Yom' Eyes, Why Do 1 Love YOrt, or
Dearly B eloved. Each tune has a fresh concept
in the arrangements of Russ Garcia.
As for the stereo, the central location -of
the voice makes it easy to spot one of the
best signs that miking was ideal at this session-the voi ce appears to originate in an area
several inches in front of as welL.. as._beh ind o
t he loudspeakers.
George Wright Encores
Hi Fi Tape 0 R 702
George Wright Encores (Vol. 2)
Hi Fi Records R 711
The symbol 0 indicates the United
Stereo Tapes 4-track 7 Vz ips tape
number.
Tenderloin (Original Broadway Cast)
Capitol SWAO 1492
Boasting an a lbum number that should be
a cinch to r emember, this Capitol recording
deploys the season's firs t maj or Broadway
musical. The lull that has separated the end
of the '59 season and the resumption of activity in the Fall of 1960 demonstrates more
than ever the importance of the musical stage
in the plans, of the record industry. Even on
records, Tenderloin underlines the import ance
of theatrical know-h'o w that only a n experienced production team can bring to a show.
The producer s, Robert Griffith and Harold
Prince, have already given Broadway such
outs tanding attractions as "Pajama Game,"
"Damn Yankees," "West Side Story" and mos t
r ecently, "Fiorello." In tbelr latest effort,
which stars Maurice Evans in a singing role
as a crusading minister, they reaffirm their
faith in New York City as the plot center of
their theatrical universe. This time t hey zero
in on t he area known as the Tenderloin in the
1890's- the favorite district of police captains, tabloids, and the more versatile funster s
in the male population.
Some seven years ago, the producers began
to plan a musical based on the famous antiTenderloin crusade of the Rev. Dr. Charles
Parkhurst. The appearance of a Samuel Hopkins Adams book on the subject two years
ago got the ba ll rolling in earnest. The entire
"Fiorello" team-director George Abbott and
his co-author J erome Weidman, composer
Jerry Bock, a nd lyricist Sheldon Harnickwent to work on this show a week after
"Fiorello" opened In November, 1959. Th e
rowdiness of the local color is best depicted
in the choral number s by the Tenderloin
crowd. Littl e Old New Yo-r k and How the
Moncy Changes Hands are gas-lit endorsements
of t he status quo. The two best ballads in
the score are Art'ijicial Flower8 and the haunting lJIy Gentle Y oung Johnny. The first is a
standard t ear jerker but J ohnny, as sung by
Eileen Rodgers, has the appeal of the t rue
folk ballad. Maurice Evans r eveals a servicea ble voice fully up to the demands of his crusade. Those who know him solely in Shakespearean roles may be surprised to learn that
this is his second Singing role in the theatre.
Capitol's stereo sound in this a lbum rates
a special word. Their m iking theory in past
show a lbums has aimed at spaciousness
achieved in the Simplest fash ion. Instead of
resorting to reverb units for illusion of theatre liveness, they have been soalring up a
maximum quota of room acoustics by the simple expedient of refUSing to cr owd their performers. Compare this recording with the
original cast production of "Music Man" a nd
you'll note the same effective u se of lively
surroundings. The "Tenderloin" recording enjoys darn near 30 per cent increase in r ecorded level a nd a decided improvement in
frequency response.
* 12 Forest Ave., Ha st'ings-on-Hudson,
N ew York.
The Unsinkable Molly Brown (Original
Broadway Cast)
Capitol SWAO 1509
Andre Kostelanetz: Unsinkable Molly
Brown
Columbia CS 8376
You may detect traces of more than one
rags-to-riches play in this saga of a mining
town tomboy and her struggle to attain acceptance in Denver society. The line that best
sums up her humble beginnings occurs In the
program notes describing the start of Act I.
It's a sentence that struck me as a new and
delicious model f"or musicals of this type, "As
the curtain rises, Molly and her brothers are
rasslln' in front of their tumbledown shack
in Hannibal, Missouri. " Once that business
is out of the way, accompanied by Meredith
Willson's marches and saloon songs, Molly
proceeds to fight her way up every ladder in
sight. She walks from Hannibal to the mining
town of Leadville, Colorado. After a brief
career as a saloon entertainer with a onesong repertory, she marries Leadville Johnny
Brown who soon becomes the wealthiest miner
in Colorado. Her saucy struggles in Denver
and European society take up the rest of the
plot. Her refusal to sink with the Titanic explains the title of the show.
Tammy Grimes, in her juiciest role so fa r ,
carries most of the show with such tunes as
I Ai n't Down Yet, Beny Up To The Bar Boys ,
and Beautiful People of D enver. Yet Miss
Grimes wou ld be the first to admit that h er
leading man, Harve Presnell, carries off top
vocal honors in his fiL'St Broadway show. The
26-year old Californian should have no difficu lty establlshing a solid career on Broadway
in view of the rich flexibility he br ings to his
th ree main songs. I'll Neve,' Say No and the
Enropean-flavored Dolce Fa,' Niente hold
promise of the most frequ ent performance
ou tside of the Winter Garden Theatre.
Hard on the heels of auy major musical
these days comes a batch of "cover" albums,
non-cast recordings that u se the score for
t heir own purposes. The Kostelanetz instrumental version was early at the starting gate
with eleven "Molly" tu nes selected for their
buoyancy in orchestral garb. His arrangers
have had to struggle with a situation that
other slick orchestras will face. The homespun sections of the score don't come over
with very much conv iction. Columbia'S Rtereo
gives a wide frontage to the orchestra's sound
with good pinpointing of the violin and cello
sections.
Margaret Whiting Sings the Jerome
Kern Songbook
Verve 0 VSTP 243
If your budget allows only fifteen t ape~ a
year-make this one of them! It could be that
only another reviewer exposed to an average
year's recordings would join me in such a
glowing estimate. Everything about this PI'oject is top drawer. Within the tape equivalent
of two record albums are definitive vocal sty lings of some of the greatest J erome Kern hits.
This release should return Margaret Wlliting
to the popularity she enjoyed when her version
of Moonlight in Vermont was in the limelight.
Only a naturally poised voice with genuine
pol ish can do justice to songs sucll as Smoke
Let t he beginner demon strate to his unsuspecting neighbor the agility of his new stereo
record in making the sound jump from speaker
to speaker. 'Vhen I entertain an "oriented"
friend and the shop talk turns to the investment required these days for really good bass
reproduction. I dig out this recent pair of
releases by Georgie Wright. The first , a stereo
tape; the other, a mono disc of similar elections. If the comparison is confined to frequency response, a good mono disc and a fourtrack tape are a reasonably fair match. Both
can operate in the region of the pedal notes
on almost equal terms. Assuming that your
amplifiers and speakers can deliver substantial output at 30 cps, the comparison is quite
instructive.
Start with the mono disc and the bass
sounds pleasingly plump--until you switch
over to the tape. Then the pedal notes feel
like the real thing. The difference is explained
when you go back to the disc. Then what first
seemed like authentic a nd robust bass is
shown up for what it really is. The fundamentals are on the tape. The disc, in Its low
end response is merely pumping strengthened
harmonics. Despite the fact that a mono
groove can accommodate wider excursions with
less risk of overcutting than a ster eo disc,
even this somewhat better-than-average mono
HI Fi r ecord cannot match the tape's bass response. George Wright, in novelties or standa rds, is one of the very few organists with
sufficient technique to encourage r epeated
listening and his roster of tunes in each of
these releases is tops in divers ity and s how·
manship.
Felicia Sanders: Songs of Kurt Weill
Time 0 ST 2007
Time is one of the newer labels that
wouldn't be caught dead in the market place
with a gimmick-free recording. Knowing they
were ardent proponents of ping-pongery, I
had to suppress a qualm or two when I opened
this tape reel containing sh ow songs of t he
great Kurt Weill that have long deserved
wider circulation. Surely they weren't planning to toss the voice of Felicia Sanders from
cha nnel to channel. I was relieved to discover
t hat the major departure from normal procedure rested in t he rather exotic reason ing outlined in the album notes that attempted to
explain their placement of voice, rhythm section, and brass in the left channel-strings
and woodwinds in t he right. The first eyebrow
lifter was this sentence in the liner notes.
"There is so much musical logic in reco rding
a vocalist in this fashion that one wonders
why no one realized it until Time's experiments led the engineers to the inescapable
conclu sion that this was the way to do it."
My reaction was immediate. In fairness to
other labels, it should be pointed out that
this technique is hardly new with Time. I
happen to have in my collection of stereo
discs a recording called "Ruth B rown Late
Date" (Atlantic 8-1308). That disc is at leas t
a year and a half in age yet it places the
vocalist in the left channel and most of the
orches tra in the right.
The other unu sual claim on the jacket lends
itself to more discussion. Some recording eng ineers are sure to question Time's implication that center placement of the singer in
stereo inev itably leads to blurred reproduction. Even more difficult to fathom is the statement that placement of a vocal soloist in one
channel means-in their own words-that
"The voice does not come from the four walls
a nd merge at some central pOint. "Given conditions suffic iently e ."aggerated, central placement-or any placemen t fo r that matter-can
AUDIO
•
FEBRUARY, 1961
_ The FISHER FM-200 represents a major revolution
in tuner design! For the first time ever high fidelity
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ever a tuner with a Golden Cascode Front-End, SIX
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•
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and selectivity! _ Four IF Stages! _ MicroRay tuning indicator for precise FM tuning and Tape Recorder level
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Export: Available in Canada through Canadian-Marconi
AUDIO
•
FEBRUARY, 1961
9
be made into a problem. The best proof that
such a problem need not exist is Margaret
Whiting's Kern tape on the Verve label. As a
matter of fact, many of the Weill songs -by
FeJicia Sander s will r eveal miking difficulties
quite unrelated to those outlined in Time's
album notes. The mike selected for h!lr u se,
h owever effective it may have been in brightening percussion sou nd in other releases, is
merciless in its handling of sib ilants and
breath production.
Whatever reservations one may have about
this album on technical grounds, thanks wi1l
certainly be extended to Time by Kurt Weill
fans who have been searching for a truly
compreh ensive collection of his songs. Represented here are such shows as "Johnny
Johnson," his first American pr.oduction, with
its fl avor of the European mus Ic halls of the
Twenties. The highlights of Weill's flfteenyear career in this country are covered by thegreat hits (Septetnbe-r Song, Spea /, Low, etc.)
and lesser-Imown excer pts from h is last three
sbows-"Street Scene," IILove Life," and "Lost
in the Stars." Tile only competition this re.ease faces on tape is the Warner B l·OS. recording of Weill instrumentals entitled "Speak
Low."
Jose Melis at Midnight/ Many Moods
of Melis
Seeco 0 SEP 301
PLATE SUPPLY TRANSFORMERS, 3-PHASE, 60 CYCLE DRY TYPES,
rated from 7.5 to 250 KVA for Class A or B operation.
Peerless 3-phase transformers of the type shown above are just one
more reason Peerless has led the industry for 25 years . Like Peerless
transformers of all types - including the specialized miniatures pioneered by the company-these high power plate supply transformers
meet the most demanding operating requirements. To insure best possible flux distribution, cores are built of high quality grain-oriented
silicon steel. The units exhibit high permeability and resistivity and
extremely low hysteresis loss. leakage reactance, once established by
your application, is held to closest tolerance. Final testing covers voltage ratios, polarity, inductance, resistance, core loss, temperature rise
under full power and all other important factors.
These units are just one more proof that whatever your transformer
needs, the experienced Peerless experts can fill them best. Units range
from 1/1 of a cubic inch to more than 20 cubic feet, from fractional
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a
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@PEERLESS
ALTE[
~
~
10
ELECTRICAL PRODUCTS
A DIVISION OF ALTEC LANSING CORPORATION
6920 McKinley Avenue, Los Angeles 1, California
Those viewers of the Jacl{ Paar show who
have fe lt that the piano a nd orchestra of
Jose Melis are not prominent enough in Ule
. proceElding~, llave a ('b ~nce to indulge themse!,vr,e s.) lb');f Uiat. tb~ Seef;~ label is out on tap~.
A 'the- key artist 111 their first release, Melis
dEl:ti:ionstt·ate,s in this Twin-Pak r eel (tape talk
for ' t\VO record albums) that his popularity
to date is not founded solely on prox im i ty to
famous , personages. Some p ianists achieve
fame on the strength of a qui r k in style.
Others work hard to become background
pianists ~' devoid of style. Melis belongs to
neitbeffi ' grQup. With only a small assisting
group in 'lOl!1e of the numbers-a full orchestra in the ~e!'t-he gets to the meat of the
melody i'n , commendably masculine fasbion.
Tbe r ecording- of the piano is business-like
a nd the cboice of tunes unhackneyed.
A Journey into Stereo Sound
,
London 0 LPM 70000
Back in June of 1958, whe n some of us
were wondering whether the stereo disc would
make the grade, London helped to resolve tbe
issue with tbe release of this recording. Virtually everyone with access to the best playback equipment available at that time immediately recognized the stereo disc version of
this recording as the first example of impressive frequency response in a two-channel
groove. Tbe selections heard on this sampler
were a hodge-podge of just abou t everything
London had in stereo at tbe time; bits of
symphonys, concertos, oratorios, pops a nd
documentary sounds.
My favorite test bands featured a rehearsal
sequeuce of a recording session (Ansermet
lead ing the Suisse Romande Orchestra in
Stravinsky's "Rite of Spring") and the d ist inctive sounds of a European train at its
station. In tbe Strav insky excerpt, just about
e,' ery low voice in the orch estra was working
to produce transients. In the train episode,
tbe thud of t he side doors being closed was
recorded at frequencies that were l ow enough
to show up differences in the response of a
succession of stereo cartridges coming on the
market at that t ime. Now tbat t he same material is out on a four-track reel w itb little
if any limitation in stereo separation, adequate tape playback facilities can bring the
listener witbin hailing distance of the sound
on London 's master recording.
Patachou Sings Broadway Shows
Audio Fidelity AFLP 1948
Les Grande Chansons (Vol. 1): Patachou
Columbia WS 318
In lbe course of her b:lingual traversal of
Broadway on the Aud io Fidelity disc, Pata<"hou works out a neat solution for the record
buyer who would like to Own t he hit songs
from "Irma La Douce"-in French. Tbe show
(Contimted on page 86)
AUDIO
•
FEBRUARY, 1961
The Quiet Sea and the new ADC-l Stereo Cartridge
There is a new and different kind of stereo cartridge for
people with a special kind of sensitivity to the world
around them. It's called the ADC-l.
Hear your favorite records played with this new pickup .. . Enjoy brilliant highs and thunderous lows free
of the slightest evidence of distortion. Experience subtleties of timbre and tonal gradation you never suspected
were in your discs. With the ADC-l you will get the
same level of high fidelity sound playing after playing;
the ADC-l 's low tracking force reduces record wear to
the vanishing point.
The sensitive person's response to beauty in nature is
usually spontaneous and needs no explanation. The thrill
experienced when listening to fine music reproduced by
AUDIO
•
FEBRUARY, 1961
the ADC-l is also spontaneous and elating, but here an
explanation is in order.
Actually, no one factor is, nor can be responsible for
the ADC-l 's startling performance. The combination of
excellence of design plus precise craftsmanship provides
the answer.
The ADC-l must be experienced to be enjoyed. It is
at your favorite dealers. Hear it today.
COMPLIANCE: 20 x 10" ems/ dyne
DYNAMIC MASS: .5 milligrams
CHANNEL SEPARATION: 30 db from 50 cps. to
7,000 cps.
FREQUENCY RESPONSE: Unusually flat: plus or
minus 2 db: from 10 cps. to 20,000 cps. with useful response exte nding well beyond 30,000 cps.
STYlUS TIP RADIUS: .0006"
RECOMMENDED TRACKING FORCE: 1 gram or less in top quality tone arms
Audio
Dynamics Corporation /
1677 Cody Avenue. Ridgewood '27, N . Y.
11
ere.
edward TatnaliCanby
TWIN-CHANNEL
HOME RECORDING
For the life of me I can't find the back
issues of AUDIO, a couple of years ago, in
which I described my experiments in home
recording via stereo tape, two mikes in
hand. But I do remember that I dwelt for
a few lines on what seemed to me a quite
remarkable and unforeseen discovery, that
home amateur-type recording via two channels is both wonderfully effective and as
tonishingly easy-far more versatile, more
foolproof than one-mike, one-channel recording of the usual sort.
I put off detailed discussion at that point
for the best of reasons. It was academic.
Few people had stereo recorders to play
around with. Stereo was to listen to, and we
were fully preoccupied in those days with
listening problems-how to get stereo from
tape, then, soon, from disc. The market was
beginning to fill up with so-called "stereophonic tape recorders," but virtually all of
them were in plain fact mono recorders and
stereo players. All except for a handful of
imported models and a few tape decks of
the Viking or Bell type that could be acquired, to choice, with dual-channel recording equipment.
The Mono S't andard
It was obvious that the general public
was first going to learn about "pre-recorded" stereo, on tape and disc. One thing
at a time. Moreover, it was clear that the
then-new "stereo recorders" were actually
a familiar phenomenon, the transition
model, and that real home recording via
dual channels would have to wait until
newly designed recorders came into production. The transition machines, originally
intended for mono, didn't have room for
home two-channel recording's bulkier components. Only the European makers resolutely went ahead with their honest but
clumsy adaptations for full stereo recording on mono-type models, notably the
Tandberg 5-2.
And so, right up to the present, the great
bulk of our home tape recording has continued to operate on the well-tried mono
standard. The machines may have been
called stereophonic and they have become
more versatile in many ways, playing all
sorts of tapes, full-track, half-track, quarter-track, stereo, mono. But as recorders,
they have remained flatly mono. I suspect
that those relatively few recordists who
have acquired Norelcos, Tandbergs, Uhers,
or tape decks with stereo recording preamps, have not done very much as yet in
the way of stereo recordings via mikes. It
isn't in the air-not yet.
But now the moment has come. This season for the first time the "average" American tape buyer is going to run into twochannel home recording in earnest. The
newly announced models, at last and inevitably, are true "stereo" recorders. Dual-
12
channel recorders. And the great American
public has another big entertainment question to face--shall I buy stereo recording
(as well as stereo playback)' What good
is it for me' Is home dual-channel recording worth the cash ~ What can you do with
iU
After all, though we've actually had
four-track stereo playback equipment on
the market for many months, it's only now
tha t one of the biggest of the U. S. popular
big brauds has come forth with twin-channel recording-no less than Web cor. And,
if I may paraphrase, as Webcor goes, so
goes the nation. Now it'll be full-page ads
in Lite and the Post, pretty models on TV
with two mikes alluringly held in their
lovely two hands. This is it! Two-channel
home recording is here. L et's get on the
bandwagon.
Mr.Snoozebury
Well . . . almost. Not quite. The new
models are coming out, but the way most
folks act you'd never know it. These words,
I'll wager, are being printed comfortably
ahead of the boom, maybe by a year or so
as far as the well-known American smalltown backwoods are concerned. Just ask
your local dealer and see.
This last December, for instance, an
ardent local lady called me up in our small
town in Connecticut, she's head of the local
music school, for advice on a new tape
recorder. The school needed one for its
teaching and she knew I knew all about
such things. She would prefer, of course,
a recorder that had no more than one pushbutton, for aU control functions, and it
shouldn't cost more than, say, forty-five
dollars. This she implied in delicate language without saying so exactly- I got the
idea all right.
This was a bit arch, on her part, for as
it turned out she was going to pay a lot
more and alrea dy knew it; but she had to
test me out against her local dealer, just
to be sure. I dutifully told her that tape
didn't come as cheap as disc equipment and
she'd have to pay more, if she wanted a
really "good" machine; she replied she
guessed as much, since she'd asked a.t the
local hi fi and camera shop some twenty
miles away-in fact, she added brightly,
she was there right now and Mr. Snoozebury, the proprietor, had showed her some
very interesting new machines though they
were, indeed, dreadfully expensive.
You can picture my visions of Mr.
Snoozebury listening a foot or so from the
phone, but I manfully ploughed in and did
my duty. I suggested flatly that before she
bought anything she should consider a
stereo recorder.
Long pause. A what? .. . I didn't quite
hear what you said, Mr. Canby. Dreadful
telephone service .... (She's slightly deaf,
and never more so than when life offers
her new complications.)
--STEREO, I repeated carefully. I could
see the handwriting on Mr. Snoozebury's
wall, but I had to go through with it. A
stereo RECORDER.
-Wha ... , Well, Mr. Canby, we really
hadn't thought about those new stereo tapes
though I'm sure they're just lovely. Our
little record player is quite adequate for
our very modest. . . .
-No, I said patiently, I mean a stereo
TecoTder. One that records on two tracks
at once, you know, one of those f.gur-track
machines .. . .
-But Mr. Canby, we only need one recorder, not four. I'm sure that Mr. Snoozebury. . . .
I ignored this killing logic and continued
doggedly. Yes, I know it will cost somewhat
more, but in a music school, you see, a
machine that will take down TWO recordings at once can be of invaluable help in
all sorts of educational situations. Take,
for instance, a violin and a piano . ...
-But Mr. Canby, I'm quite sure we
really can't afford even two recorders. One
will be quite enough for the present.
Though I am sure the piano department
would be glad to. . ..
-Two microphones, you see, I interrupted. Both running into one machine.
They make the same recording-I mean,
almost the same. And with four tracks... .
-Four tracks' (A new idea was getting
through.) You mean a machine that plays
four different tapes' How interesting! But
I don't really think we can afford anything
quite like that right now. You see, we've
raised only enough money for one tapeI mean one recorder ... Oh dear, what DO
I mean' Mr. Canby, do let me ask Mr.
Snoozebury, right here, what he thinks
about these four-t-ape machines.
I picked that up very hastily: ask him
whether he handles the Norelco, or the
Tandberg, or the Uher-they're all stereo
recorders, imported from . . . .
-Mr. Canby, Mr. Snoozebury has the
nicest tape recorder right here, and" I just
wondered what you thought of it. (The
cat, of course, had been waiting all this
time to get out of the bag. Tae lady had
every intention of buying the one she'd
long since decided upon. They always do.)
It's a-(pause, muffled voices in background) he says it's a Wollysack, or is it a
Gunnysack' And he'll give the School a
very good price, since we do so dreadfully
need a recorder for our work.
Well, I gave up on the spot, as you can
guess. I enthused over the Gunnysack, alias
the W ollensack, and opined that for her
purposes it was an excellent buy. And
which model was it-did it play stereo '
She hadn't considered this, and acted as
though I were bringing up a tired subject
already well got rid of; so I didn't bother
to find out whether this was the half-track
mono model with lO-watt built-in power amplifier, or the modification that plays stereo
but is minus the power amplifier. As for
any thought of two-mike, dual-channel Te·
cOTding, I mentally chalked this conversation as Round One-a Total Loss. A rout.
No, two-channel home recording was not
here quite yet.
Mr. Snooze bury (his real name is only
slightly different) evidently had never
heard of two-channel at that point. Nor
did he know about the assorted European
imports I suggest ed. Nor any new Webcors or Reveres. If he did, he wasn't telling
my lady friend. But as for the Wollensack,
now there was a really fine little machine.
. . It is, too.
*
*
*
I'll admit that this is a somewhat enhanced transcript of the original phone
conversation. But it does represent the gist
of reality. If you doubt it, try your own
AUDIO
•
FEBRUARY, 1961
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heads permitting off-the-lape monitor. 2
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controls, switched sound-on-sound record·
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take-up reel motors; hysteresis synchro.
nous capstan motor. Individual solenoids
for pinch-roller & tape lifters_ AII·electric.
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Precision tape guidance & sweep loading
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FM TUNER
Switched AFC (Automatic Frequency Con·
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Frequency Response: 20-15,000 cps±ldb.
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Switched "w ide" and " narrow" bandpass.
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AUDIO
•
FEBRUARY, 1961
13
local lady·prospect. I think you will have
noticed, in any case, . one thing of signifi.
cance. This lady would not buy home two·
channel .r~c01'din~, but she lmew all about
tape recording itself, and was eagerly and
wisely ready to spend cash for it. What's
1110re, she knows what to do with it when
she gets it-mono·style, at least.
Now pause to remind you rself what a
triumph of long·range education that is!
Maybe a good ten year's worth.
It seems but a moment ago that other
nice ladies were asking me about buying a
new phonograph and didn't I think this
lovely HEmplewait was just the thing~ New
speeds~ You know, Mr. Canby, we have so
many precious old records, we really won't
be able to affo rd any new ones, and we do
like those we have so much, . , . LP ~ What
was thaH Long Paying~ You mean buying
on the installment plan- dear me, I hadn't
thought of t hat . I'll have to ask Mr. Snooze·
bury t Ills very minute. He's just showing
me some new invention, is it the Wire
Brush ~ It plays jazz on picture wire, but
I don't really think, for my purposes .. . .
MI'. Canbi}', I really don't like all this noisy
jazz music ... . de yo.u~
That would have been around ,1952 and ,
I would not have tben dreamed of suggest,..~
ing a tape recorder to the lady. You call.
imagine how far I would ha,7e got! So, in
ten more years, I'll bet, Mr. Snoozebury
will have a storeful of dual·channel tape
machines and the 1adies will be calling me
all over the place about them. No more
wire recorders.
Therefore, let's anticipate. What has the
d ual·channel tape rec'order to offer to the
home ama' eur aud semi·pro (schools, etc.) ~
Semantics
First, you must untangle tbe semantics.
No nice lady in bel' right mind can make
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A~d!o
14
head or tail of our present jungle of tape
terminology.
It's not four recordings, you explainmerely four tracks on one tape. You don't
use them all at once. You use two of them
in one direction and two the other· it works
exactly like the old system. (That's reas·
surillg.) You run the tape through twice.
Just pretend it's a regular recorder. (That's
the solid approach .) Except that now you
have two mil<es instead of just one. On e
mike in each band . (Who uses mike stands'
If not in the hand, then on a table, or sit·
ting in a chair. ) When yo u play back,
the sound comes out of two spea kers. Sim·
pIe. Easy.
That is the biggest point to get over in
our coming missionary work among th e
mono tape heathen. Tell 'em it's just like
it always was-you make a tape, tben you
play it. Aim and shoot. No special profes·
sional know-how for dual·mike recordi ng.
In fact-and here is Point Two-it's
twice as easy, twice as sure-fire. This is
the big surprise, t his is the honest plug
that means what it says. It's the new sensation that's coming our way in home tape
recording. It's the answer, every time, to
the coming nationwide chorus of murmur·
ing objections - home·stereo·recording-isimpractical· because· stereo -i s· for· the· ex ·
perts·an d· who -wan ts· to·do· professiona l·stu·
dio-recording·ill-the· home ·and ·anyway· it's·
expensive.
The fact is, as I have quickly found by
home experim ent, that two·mike home reo
cording is very seldom stereo at all. It's
dua l'channel, all right, but not stereo.
Stereo is, indeed, a tricky technique that
demands a professional sense of microplion·
ing. It can be produced in the hom e, just
as good pro-style mono recording occasion·
ally turns up on a home recorder in good
hands. Nine chances out of ten, though,
your home recordist won't get real stereo
sound in any propel' sense at all; or his
stereo will be bad stereo, as such. Instead
-the thing to do is to forget all about
stereo and concentrate on mucb sinlpler re·
cording techniqnes.
The thing to do is to avoid the very
te rm "stereo" in our whole -approach to
this new home two-channel recording. It
doesn't apply technically, for the most p art.
H has too many wrong associations. It is
difficult-when done in professional style.
B ut good two·channel recording isn't diffi·
cult at a.ll in tbe home situation, if you
fo rget about stereo.
Dual-Channel
I propose, then, that as often as possible
we refer not to home ste?·eo ?·eco?'cling but
to horne dua l·channel recording. This avoids
a whole series of confusions an d says ex·
actly what needs to be said, without drag·
ging in com plica tions. What's more, it
makes talking about t ape recorders a lot
simpler.
Thus-your four·traclc recorder now can
make a dual·channel recording. YonI' half·
track recorder usually made a sing le-chan·
nel recording though a few models conld
record dual·channel. (NOT "two·track" I )
Any old recorder can make a single·channel
recording, whether full· track, half·track or
quarter· track.
If for clarity we will confine "track" t o
its t echnical meaning, a recorded track or
trail of information on a tape, and use
"challl1el" in its proper sense, as the com·
plete communication system from mike to
track or from track to speaker (or both
AUDIO
•
FEBRUARY, 1961
-simultaneously) ,. we'll do much to help the
public get itself clear on fundamentals, '
before taking t he h oped-for plunge into
·dual-channel home recording.
Stereo, then, is a p r ofessional-type sound,
as purveyed via commercial recordings,
dual-channel recording is any type of reo
cording via two channels, steI'eo included,
If you a ren't goin g to stress true stereo,
t hen what do you do with your home dualchannel mac hine~
Almost any old thing, I n my somewhat
randomly purposeful experimenting to date
I've prod uced some wonderfully amusi ng,
effective, slick, realistic, natural-sounding
tapes, and most of my "technique" has been
deliberately, absurdly cru de, once I caught
onto the fact that this is what works best,
The zanier your mike positions, given
the all-important duality, t he trickier are
the results, The medium is astonishing . It
untangles th e nuttiest mu ddles, disciplines
the undisciplined, makes neatly formal rows
out of helter-skelter masses of people, reduces the wildest mike gyrations (via waving arms) to staid immoveability, ... But
let me pass onwards t o several categories
of zany simplicity t hat occur to me as helpful in dual-channel recording, t hough in
practice they: overlap more or less continuously.
THIS 1STHE
GREATEST
dCONTINEUTAL'
n
0 F THE M
ALL __ _
The Two-Point Close-Up
The simplest and best home two-channel
technique, the most nseful of all and the
most surefire, is t hat which I'll call t he
Two-Point close-np.
Pick up your two mikes and stick them
as close as possible t o two different sounds.
Make sure they are different. (Allow for
level, of course-close-up sound is usually
loud.)
,
Put one mike three inches from a fo lk
singer's mouth (amateur, of course-no
Metropolitan Opera voice,s in this show);
put the other a couple of lllches away fro111
the strings of a guitar. Keep them apart.
Space your people five or six feet or morc
apart. (And space your playback speakers
even f urther, for enhanced effect.)
Or set up an amateur Romeo and J uliet
(again, serious but a~ateur) on two mikes,
w,ell separated, Or SIt two of your small
hds on two TV cushions and get 'em to
t alk-with giggles. Ohannel A : "What's
black ancl white and j'ead all ovej'?" Ohannel B: "(Giggle) A l\TEWSpaper!!"
The palpable fact is that the question
on playback, is asked out of one loud~
speaker and the answer comes, across the
room, out of the other. That is t he big new
dramatic sensation. The spatial dialoguc
each sound inside a different speaker (not
behind it), makes for a lively, surprisingly
engaging effect of "two-ness," mu ch more
attractive than the inflexible "one-ness" of
the ordinary mono recording! Just watch
the listening heads bob back and forth,
Two-point commercial stereo is often prett y
dull, ping-pong style. But in home r ecording it's something else again. F un, effective, useful.
Almost any sort of duet or dialog is
made much more interesting by this simple
home technique. Ordinary conversations
grow vivid when one person is in each
speaker, instead of the nsual situation
where several voices are superimposed one
on top of the other f or a spatial monotone.
the
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It may occur to you that t hese dual re-
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(Contin1£ed on page 58)
AUDIO
•
FEBRUARY, 1961
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15
EDITOR'S REVIEW
THE "BEST" LOUDSPEAKER
R
amplifier phono
pickup, tape recorder, or microphone, the last link
in the entire chain of any sound reproduction system is the loudspeaker. And no matter how good the
rest of the equipment-including the original source
-the loudspeaker is the one element most likely to
introduce its own characteristics into the over-all
sound quality.
Some audiofans, searching for the ultimate in a
loudspeaker enclosure, take the viewpoint that sound
should be reproduced by some device with "resonance. " Their fundamental idea seems to come from
the fact that a violin, for instance, has "resonance"
and that therefore-since it is recognized as stlcn a
good sound . producer-a loudspeaker should be designed like a violin. Others choose a different ]Il!strument tid copy in order to make a loudspeaker C"lIDoinet,
with no better results.
Sticking to the violin analogy, it must be recogniized
that its" frequency response" is not flat thromghout
the entire audio spectrum. Actually, it is freq'\;l!mcy
response primarily that makes the difference between
a fine instrument and the poorest of fiddles. Slllip>pose,
for instance, that we had a violin which had a: IO-db
peak in its frequency response at 1400 cps-a ]to·t impossible condition. Let us suppose further that we had
a loudspeaker built in the form of a violin just like
our original so that there was a 10-db peak in the loudspeaker at 1400 cps. Then we play music on the origi'n al instrument and reproduce it on the violin-loudspeaker. We would have a resultant peak of 20 db at
1400 cps. This is not unlike the trouble in dubbing
tape after tape in a consecutive pattern-that is, copy
1 from the original, copy 2 from copy 1, copy 3 from
copy 2, copy 4 from copy 3, and so on. This is in contrast to the normal method in which copy 1, copy 2,
copy 3, and so on are all dubbed from the original.
In the consecutive pattern, a 2-db peak in the system
anywhere would put an equivalent peak on copy 1;
a 4-db peak on copy 2, a 6-db peak on copy 3, an 8-db
peak on copy 4, and so on. This practice is not usual in
commercial dubbing, but if audiofan A makes a copy
from his original tape and gives it to audiofan B, and
he copies it and gives it to C and he copies it and gives
it to D who-and so on-the frequency response of the
last. copy will contain all the defects of all of the r ecorders of the system.
Thus what is needed is a loudspeaker that is entirely
inert-it should not introduce any characteristics of
its own into the reproduction. That is, of course, askEGARDLESS OF SOURCE MATERIAL,
16
ing a lot, for there are no perfect loudspeakers. By the
same token, if all manufacturers were able to make
loudspeakers which were perfect, then all 0'£ the products of the various manufacturers should sound alike,
and everyone knows that they do not.
Now it is to be assumed that every manufacturer
strives to make a good loudspeaker-certainly the
basic principles of craftsmanship as well as business
demands that he do so. But he must also make a salable
product if he is to stay in business. And this is where
the differences come in. Those who have the responsibility of passing on the over-all sound quality of the
product may have different tastes, and those tastes are
certainly reflected in the speaker. The main problem
in loudspeaker manufacture is to turn out a product
that will appeal to a large enough segment of the
listening public to make it economically successful.
We are so often asked, "What is the best loudspeaker?" or "What speaker should I buy ?" For
many reasons we cannot answer that question. First
and foremost is the unfairness on our part if we were
to tell enquirers that the product of one of our advertisers was better than the product of another. If we
were to say that we like X's speaker (or amplifier or
tuner or phonograph cartridge or turntable or whatnot) Y is certainly not going to like us any more.
Neither is Z nor A nor B nor anybody except X.
The most important (to the speaker buyer) is the
fact that not everyone likes exactly the same type of
sound. And since all loudspeakers do not sound alike
-the biggest understatement of the year so far-the
only logical answer is for the individual to hear as
many as possible and then select the one that he likes
best. To be sure this is difficult for the man who is
not close to an audio salon or who must buy from advertisements alone. We feel that within the same price
class there is not a great differ ence in quality. Common sense tells us that it is not likely that one manufacturer can make a loudspeaker for $19.85 that is
just as good as another's unit at $495.00. Our advice,
then, is always, "Choose the product of any reputable
manufacturer in the price range you want" when you
can't compare a lot of them. When you can, we say,
"Choose from the products of any reputable manufacturer and pick the one that sounds best to you. "
Even if we would, we could not say which loudspeaker
you would like best, and anyhow you're the one who
is going to listen to it and we don't want to "shoulder
the blame" if you're not satisfied.
And as a final word, hear as many as you can at the
Washington High Fidelity Show, February 10-12 at
the Shoreham Hotel.
AUDI O
•
FEBRUARY, 1961
An ultra-linear professional pickup
for recording channel calibration ,
radio stations and record evaluation
by engineers and cr i tics ... from
$48.00
I
Collectors Series: Model 380-A preci s ion pickup for th e discriminating
r ecord collector . .. fro m $29 .85
1j
Pro-Standard Series: MK II-A pro·
fes s i o nal pi c kup out s tandin g for
quali ty co n tro l . .. f ro m $24 .00
/
StereoPlayer Series : Stereo 90A fi n e quality stereo magnetic pickup for the audiophile . . . $16.50
i
Illore for everyone .... :nlore for
eve~y 'applicatiOI1.
.. . so much more ·f or everyone' ... f or every
application ... in the complet:e line o f Stanton
Ste r e o F luxvalves .
H e re i s responsible p e rforman c e ... in four s uperb
Jililodels ... for aU "Who caD hea~ t:he differerice.
From a g e ntle pianissimo to a r e sounding
cresce ndo-every :rnove lllent p f th;e s tMlus J?e flects a
quality touch possessed only by the
Stere o F luxvalve .
L ISTEN! . . : and you will agree Picke ring has more
f or the best of e v e rything .~ n record r e productio n
-mono or ste reo, More Output:-More Channel
Separation-More Response-More Record Life!
In short ... more .t o enjoy ... because ,' the re's n a ore
quality for more listen.ing pleasure.
Ask for a Stanton Ste reo Fluxvalve *
demonstration at your Hi -Fi ,Dea ler today'!
*U. S.
P.te "~
No. 2,9 17 .590
Send for Pickering' Tech-Specs-"a
guide for planning
a stereo high fidelity ·s'\'stelln . . . address Dept. B21
STEREO F LUXYAlVE, STE REOPl AYER, C OL L ECTOR S SER I ES" PRO· STANDA RD SERI ES, CALIBR ATI ON S TA. N DA RD AR E lRAO EMI\R K$ US E D TOO EN Ol
e
Q UALIT Y OF P IC K ERING COM PANY, I NC. PR O DUCTS .
A Case for the Custom Console
F. H. JACKSO N'::
A custom console to meet your specific equpiment needs is re latively simple to
construct and requires only the most basic hand tools. The approach described in
this article makes it possible for anyone to produce a furnitu re-quality console.
o PARAPHRASE THE noted sculptor's
description of the genus homo sapiens' lifetime as the "Seven Stages of
NIan," one might as easily draw the
simile anent the genus "audiofan" ! Fortunately for the writer, and his acquaintances, fired with the desire for fine reproduction of music in the home, the
stages are confined to three in number,
whose total duration need not necessa?'iZy
sum to a lifetime !
The first might prosaically be termed
the planning stage, wherein the audio
literatm'e is combed not less avidly than
are the shelves of the neighborhood emporium devoted to such wares (presided
over by the ever-patient proprietor).
The second might be termed the stage
of creation. Decision, ever procrastinated, has finally molded actions. W ithin
short days passing om scrimped savings
fast disappear into the maw of desire!
The third stage, for lack of 111<1re apt
semantics, might be called the contemp lative. This article is being composed
at that most difficult of times. For the
author, the planning and the creation
are over. The satisfaction and enjoyment of a fine concert wafting through
his home, is tempered by the gnawing
query, "Has the final stage fulfilled the
promise of the long past first~"
These stages through which the author's system developed are universal
enough in natm'e as to cause the reader
similar concern as he p lods his way
through that first stage !
T
* 6060 N.
California.
Brig7rtview
D·r.,
One problem faced, and no doubt COlllmon to fellow devotees of the audio art,
is the ever present problem of combining
audio component quality with living
room decor. Optimizing the equipment
quality somehow always seems to outstrip the desires of the distaff side to
decoratively house that which husband
hath wrought!
Secondly, there is need for convenient
access, coupled with easy component relllovability. Thirdly, it was desired to
incorporate in the design the quality of
adaptability, i.e., obsolescence conversion. Lastly, convenience featm'es compatible with the design criteria were to
be incorporated. How well the solutions
to these problems wear is the continuing
subject of both this article and the third
stage of this audiofan's career in high
fidelity.
The basic system chosen (see appendix) was to be that of a three unit stereo
presentation of both high-fidelity broadcast and phonograph programming. The
three units were to consist of separate
left- and right-channel speaker cabinetry
Fig .
together with complete component console housing for all program and amplification somces. (See Fig. 1.) The cynic
so easily states that given appropriate
sums most problems are solved. To confound this crass viewpoint, the writer
offers this system and in particular his
solution to the task of creating a furnitme setting for such a system at a
total cabinet cost of under $100! This
ca binetl'Y cost was not predicated upon
ownership of an extensive inventory of
power tools. On the contrary, the author's sole claim to a power workshop
is a vintage electric drill with a $12
sabre saw attachment!
How W ere These Items Constructed?
At the risk of offending the power
tool sellers, we must state that most local
lumber yards, for a very nominal charge,
will cut and mill any raw stock to yom
working drawings. On my unit the tolerances maintained were such that for ease
of assembly, the method approached the
so -called "kit" type of cabinet construc-
(b e low).
The compl e te sys-
te m .
Fig . 2 (right). Explod e d view of
the laminated
case construction .
GLUED &
NA ILED
BUTT
JOINT
Glendo1'a,
1/4- IN. PL YWOOD
FURN ITURE G RADE
MO LDING
18
AUDIO
•
FEBRUARY, 1961
Fig. 3. Top edges of the console are covered 'with wo od tape.
tion. The obvious advantage to this
method is the wide latitude in design permissible, Ve9'sus the justifiably limited
number of styles available from kit
manufacturers.
Another area of exp ense coupled with'
the construction of a console suitable for
milady's living room is that connected
with jointing and cementing of large
scale furniture. Rather costly jigs and
fixtures are usually r equired for such
construction. Since these items were not
readily available to the author, some
substitution became a necessity. The resultant innovation, which is felt to be
the prirp.e pne of t):l.Ose in this system,
has been termed "laminated case constructioiI". (See Fig . 2.) Cabinet makers
may shudder within their professional
stoicism to learn that this metlio.d uses
common finishing nails and. qllick-setting casein cement! The method ~as first
tried on , the construction of the .s·peaker
cabinets and the encouraging
r esults
t
prompted the use· 'o:f? the' same method,
without modificatiJm, in h)!>il ding the
console,
' ".'\
The procedure consists of two steps.
Step one is to simply butt the sides and
nail using casein glue (,several national
brands are available) . . Three-quarterinch fir plywood i;; adequate. After
counter-sinking the nail heads, the case
is rough sanded to remove any gross irregularities on the surface. Previously
cut and corner-mitered, 14-inch, furniture-grade, plywood p anels (again the
f riendly millwright at the local lumber
yard was responsible) were coated on
the underside with glue, as was the
rough case. Carefully fitted, the panels
were butted at all corner miters and
weighted until the glue set. The end
grain in this case was covered by the
application of grille molding although
an alternate method, easily applied, is to
use plywood tape. This tape method was
used extensively on the end grain covering of the console. -Most observers believe the cases are of solid hardwood
construction, -GSee Fig. 3.) This laminated case construction and the implem.entation of the Provincial motif in
all three cabinets (which helped to create
a unity of design) through use of ordinary builders molding,. did much toward
beautifying {pe ensemble. The grille
frames are aefinitely enhanced by the
graceful curves of the covering molding.
The console inset doors and the drop
'V
Fig . 4 . The top is off! Note the laminated
case construction in the end panels.
front have that added touch of detail,
which would be noticealy lacking were
these p anels of plain surface. Mention
should be made at this juncture, that a
contribution to the over-all effect was
gained by the hand fitting and mitering
of these moldings on assembly to comply
with the final tolerances existing on the
several mating items. '
The second major problem to be resolved by our design was that of accessibility, It is only within the last several
years that the ogre of maintainence accessibility has been given notice, much
less resolution, by the commer cial p ackage interests, and that primarily by the
television receiver manufacturers. It is
to be seen (Fig . 4) that this problem
was resolved most easily by the inclusion of a lift -off top in the console design. This fea ture greatly eases the disassembly breakdown of the system into
units for r epair or transport. In addition the preamplifier and tuners are so
inserted into the control panel, that
their r emoval is accomplished by simply
sliding them on their base toward the
r ear of the console for an inch or two.
This is possible because the normal
bezel-type mounting was not employed.
Insteal, a matching rectangle was cut in
the panel for each of the three units
to be mounted. As each unit face protrudes about 1,4 inch from the panel
face, it is difficult to tell whether or not
they ar e permanently affixed. This feature has already proved of value in the
case of some minor repairs to one of the
panel units, The operation took less than
a half hour, including repair of the unit.
The third criterion for our design, in
which it was desired to create solutions
amenable to our other goals, is that
called adaptability, or obsolescence
conversion. One area in which this attribute was incorporated was the design
of the speaker enclosures. Close perusal
of Fig. 5 will reveal the method used to
allow for f uture horizontal placement
of the speakers, should the need arise.
The bases' ar e entirely separate from the
speaker enclosures, and the enclosures
are finished on all four sides. They need
only be lifted off their bases, placed on
the side (after orienting the horn
tweeter) for f unctional use as a bookshelf enclosure.
In line with solution to the problem
(Co ntimted on page 79 )
Appendix
System Parameters
Compo nent
Fu nction
Mfr.
Model
Pilot
FA-670
Hea th
FM-3
Fairchild
ESL
Shure
Dynakit
Allied
412
S-1000
M3D
PAS-2
8 3 YU 793
Speakers (2)
University
Cabinets (spkr)
Custom
CUL 10 (kit form of 2
way SLOH system)
To Univ. CUL 10
Specifications
Console
Custom
AM-FM Tuner
FM Tuner
Turntable
Tone Arm
Cartridge
Preamp
Amp lifiers (2)
AUDIO
•
Right Channel Either
AM - FM or FM-FM
stereo (see below)
Left Channel FM-FM
Stereo
Record Reproduction
Record Reproduction
Record Reproduction
Control Center
Left and Right Channel
Power Output
FEBRUARY, 1961
Fig. 5. The bases are separa te and the
enclosure finished on a ll sides to permit
a variety of placements:
19
"Ersatz Stereo" Unlimited
C. H. MALMSTEDT*
A multichannel monophonic system that gives stereo some impressive competition.
in California there
is a monophonic hi-fi installation
that, in results achieved, matches the
grandeur of the country around it.
"As good as stereo!" the system has
been acclaimed. And, by a visiting symphony conductor.
"Magnificent ! It is as though I were
standing on the podium, the orchestra
right here before me !"
Whether or not these accolades are
extravagant, the fact remains that
"monophonic" applied to this installation is as pleasantly deceptive as the
name "Erosion Acres" is for the home
and grounds that house this audio system
created by its owner, Mr. Harwell Dyer
of Carmel Valley.
"How," all ask, "do you get such
marvelous sound from an installation
that looks so simple?"
The answer is: growth, of more than
twenty year s' duration; growth born of
a constant desire for improvement-of
the technical facilities and of an understanding of music, a knowledge of the
composition of the sounds t.hat were to
be reproduced with the best possible
ftdelity; things, in fact, that are not
come by cheaply, in either time or
money.
Considered by the standards of today's hi-fi, Mr. Dyer's begiuning was,
however, a modest one. A Gilfillan r adiophonograph with a Garrard changer
handling only 78-rpm discs was, back in
1938, the first nucleus of the system.
Today, the Carmel Valley installation
consists of six speakers and twelve electronic units housed in five unit-Iocatiops
I
NA RUSTIC HOME
* Box 411, Windel'mere, Fla.
Fig . 2 . The music corner, with part of the
large lib ra ry above and below t he turn·
tabl e s. Note the home· built turn table on
the left.
in and about the large living room, but
so placed that, while everything is
readily accessible, little is in evidence to
mar the furniture grouping, the decor
of the room, and the magnificient view
from it.
I nterestingly, the original heart of the
amplifying system still serves as one of
the power amplifiers- proving that the
best is always in the long run the cheapest, and that modification intelligently
applied can obviate the too-often-assumed necessity for discarding good
units merely because of age. Designed
and built in 1946 by Dyer and W illiam
H ilchey, this 300-watt amplifier utilizing
6L6 tubes feeding two 845's, in pushp ull, employed the best components then
available. Originally part of a 300-pound
rack-mounted composite unit, this amplifier was later converted by James
Meagher into a Williamson class-A amplifier of 150 watts full 'power and 75
watts distortionless output. Following
the same desire to preserve and effectively use the worthwhile and the
Fig . 1. Not ste reo
-but magnificient
mu sic . .. a mag nificie nt view .
pea ce.
20
proven, an Altec 515 woofer also was
salvaged from the earlier installation
(where it had been in an infinite-baffle
arrangement stabilized by a half a ton
of concrete within a wall) for modification and use in the present system, as
was an Altec 604-B coaxial speaker system, along with associated crossover
networks.
With these and other units as a starting point, the present unique installation
got under way in 1951, many years before the advent of commercially available stereo. As with all lovers of fine
music, the goal of the Dyers was not
only high fidelity but as well concert hall
r ealism. It soon became apparent that
Fig . 3. Electronic cabinet, fo rm e rly a
close t.
to get this realism, more was needed than
a judicious placement of good speakers.
Dyer went back to the first-things-first
principle : he decided, first of all, to design and build his own turntable. The
result leaves little to be desired, even
in these days of many fine commercial
turntables.
While few may care to go this far in a
do-it-yourself endeavor, this home-made
turntable is worth looking at bef ore a
view of the entire system.
Constant speed, free of vibration influences was the aim. Parts were picked
up here and there. I n a wrecking yard
was found a 65-pound, 16-inch diameter,
AUDIO
•
FEBRUARY, 1961
Fig. 4. Home-made 16-inch turntable.
two-inches-thick halance wheel once used
in a saw-mill-massive enough and
heavy enough to resist vibration. To one
side of this wheel was bolted a 1f2-inchthick disc of plywood. Over the plywood
a 1f2-inch disc of neoprene was then
glued. This combination became the
turntable. The problem of a motor to
turn this table was solved by a Green
Flyer motor of the type used in broadcasting station transcription turntables.
Set in an "H" saddle constructed at
home, the motor was placed on a foam
rubber pad within a cabinet under builtin bookshelves. To assure vibration-free
drive of the turntable, sections of the
drive-shaft were separated by Lord rubber couplings, with a free-wheeling device in one section of the drive-shaft.
As a precaution against overheating of
the motor during long use, a small rubber-bladed fan of the type used in automobile interiors was added to the motor
compartment. To render its operation
inaudible, its speed was reduced by the
use of series-connected light bulbs, which
also conveniel'ltly illuminate the enclosure during operational inspections.
There was one problem: how to start
this heavy turntable spinning without
asking the motor to do it. Solution: to
Fig. 5. Midrange horn disperses sound
throughout the large room, augmented
by a woofer at floor level .
AUDIO
•
FEBRUARY, 1961
the drive-shaft was fastened a six-inch
length of stiff wire protruding straight
out; to the end of this wire a small magnet was attached; at one point on the
travel-radius of this magnet a microswitch was so placed as to be actuated
when the magnet passes it the first time.
Result: manually start the turntable
slowly- and within one turn or less the
microswitch applies the current automatically, and the table smoothly works
up to the speed it was set for-33Ya
or 78 rpm.
Both the construction time and the
time required to attain full speed (about
a minute) are more than amply justified
by the performance. "If there is any
rumble in evidence, it is inherent in the
recording, not in the turntable."
More concerned with fidelity than efficiency, he decided to use the big homemade power amplifier to feed an AR-1 W
speaker in its infinite-baffle enclosure,
placed on the floor at one end of the
room. With the feed originating at the
home-made turntable, the Garrard
changer, or a Fisher FM tuner, the
AR-1 W woofer receives its input
through a Grommes 212 preamplifier
feeding a Heathkit electronic crossover,
the Low output of which was set to decline at 100 cps.
With one bass-response channel thus
established, another set of speakers-an
Altec 604-B coaxial and a 515 wooferwere mounted on a common infinite
baffle half the size of a large closet door.
To accommodate this baffle, the door
-:-::::-::--..... JEN SEN 302A
ALTEC
6048
~--......_
ALTEe 285
- - . _ ALTEC515
Fig. 6. Block diagram of the four-channel system.
With a GE magnetic cartridge and
16-inch transcription pickup arm on this
turntable, it became again a case of one
thing leading to another: where a good
audio system had inspired the quest for
a better turntable, the turntable thus
developed now led the way to a demand
for an even better audio system: "The
best monophonic thing I've ever heard,"
said one listener.
But it was a desire for a stereophonic
kind of realism that brought about the
"unorthodox" use of crossover networks
that is one of the keys to the success of
this system. This, in turn, was brought
about by the physical characteristics of
the house the Dyers purchased in Carmel Valley. With walls of unsurfaced
concrete block, a floor of smooth, waxed
cement, and a large picture window in
one wall, plus a rather high beamed
ceiling, the living room was obviously
a "live" one. A member of the infinitebaffle school, Mr. Dyer set to work accordingly-to assure, first of all, adequate but natural reproduction of bass.
was I'emoved from a closet at the same
end of the living room that holds the
AR-1 W. Bottom half of this 6-feet-deep
closet was partitioned off as a housing
for the rack of major electronic units
and power supplies, with the lower half
of the door cut vertically in the center
to provide two flap doors that could,
without jeopardizing appearance, be left
ajar for ventilation. The upper half of
the closet thus vacated was lined with
absorbent padding and utilized as an
enclosure for the two speakers. To the
same baffle now was added a Jensen
302-A "bullet" tweeter, thus making this
a four-speaker infinite-baffle enclosure
about six feet to the left of and about
five feet above the AR-1 W on the floor.
Input to this speaker system was now
arranged through individual channels
to which only the Grommes preamplifier
and equalizing system are basically common. To feed the 604-B coaxial, the
High output of the electronic crossover,
set to pass above 400 cps, was fed into
(Continued on page 81)
21
•
Computers In Audio Design
R. G. BUSCHER ':'
Through use of computers the audio engine~r can materially .reduce .the amount of. time h~ spends
on routine computations and thus incr~ase the amount of tllne avallabl~ .for ha~dlmg. design problems. Here is a description of the various computer types plus a specIfic audio design example.
In Two Parts-Part One
names such as PACE, then make the necessary changes and
650, MANIAC, REAC, 704, and start again.
ESIAC have appeared more and
Even the field of audio can benefit
more throughout our society. These are through the use of computers. The dethe designations given to the computers sign or optimization of audio systems
which are used in the areas of account- can be done on computers more quickly
ing, engineering, and research . Through and more accurately than by hand meththe application of computers, time- and ods.
money-consuming procedures are being
By introducing circuit equations into
simplified. Each year more people come computers, the laborious task of ampliinto contact with these applications. fier design, for example, can be made
Utility bills, bank accounts, savings easier. Tube characteristics can be placed
bonds, credit cards, income tax, govern- in the computers in order to determine
ment checks, and the paper work of the amplifier tube operating points. A
many other everyday activities are han- more complex design in terms of component aging effects is readily accomdled by some sort of computer.
In engineering, the speed of data processing is of extreme importance. By freeing engineers from r outine complex calculations so that they may go into new
endeavors, these machines are stepping
up the rate of progress.
Complete models of complex systems
can be computer simulated for engineers
TIME
to study. In this way the cost of optimizing a design can be reduced.
Fig . 2. Velocity of mass when the pin is
If a new system were to be built for
pulled .
each design change, the cost of development would be many times what it is
plished by parameter variation. Changes
now. Each time a design er ror was made
in resistor, capacitor, and voltage values
a new system would be required. Com. can be programmed to study the tradeputers, however, allow quick and easy
offs between power, bias, and distortion.
changes in design. On computers, "misOther audio areas such as speaker,
takes" are indicated by means of signal
cartridge and tone arm, and tone conlights, horns, or other such means. A
trol design can be investigated in similar
flip of a switch will return the problem
fashion.
to its origina1 state. The engineer can
While most of the computers in use
* 36 Ra'lI Street, Schenectady, N . Y .
today are built to perform a specific
function, they all fall into one or the
other of two classes: analog or digital.
While each class can do the problems
handled by the other, there are basic differences which make necess'ary a choice
of which type to use in a particular case.
Such a choice is made on the basis of the
problem and its r equirements. Such factors as problem accuracy requirements,
the number of parameters, and their
changes enter into this choice.
The digital computer has its greatest
use in numerical analysis work where
precise bookkeeping-like routines can be
Fig. 1. Shock absorber schematic.
set up. The analog computer has its ap-
I
N RECENT YEARS,
22
Fig. 3. Shock absorber analog.
plication in the area of system analysis
work where systems must be engineered
and optimized.
In order to illustrate the differences
between the two classes, each will be
discussed in the following sections.
Since audio design work is of interest
to the r eader of AUDIO, the major emphasis will be on the analog computer.
The Digital Computer
The digital computer is a device that
uses discrete steps to represent numbers
while it performs mathematical operations. This is similar to the operation of
an abacus. On the abacus, beads are used
to r epresent numbers. Addition and subtraction are performed by the shifting
of these beads. A similar procedure is
used in electronic digital computers. In
this case "bits" are used to represent the
numbers. A number or quantity is
changed to "bit" representation by the
use of a code. The " bits" take the form
of either the presence or the absence of
a signal. The presence is denoted by the
number "I" and the absence by the number "0" when setting up the problem.
The over-all number or quantity is then
represented by some combination of l 's
and O's, according to the code used.
By the use of Boolean algebra and
other techniques beyond the scope of this
article the various mathematical operations are performed.
The accuracy of these mathematical
operations is limited only by the number
of bits used to represent the quantity.
Six decimal places of accuracy imposes
no strain on a typical digital computer.
One of the main features of digital
computers is the memory function. By
the use of this memory a number can be
stored in the machine until it is needed
AUDIO
•
FEBRUARY, 1961
Zj
IN~UT
':.'
;;;
Fig . 4. Operati onal
amplifier.
ej
0---+_--0
A. NO FEE DBAC K
B. WITH FEEDBAC K
for computation. Upon being changed it
can again be stored until further needed.
For example, a bank account balance
could be kept in a computer's memory.
When the depositor makes a deposit, the
teller, by pushing buttons, could call the
depositor's balance from the memory.
The new deposit could be added and the
new balance put back in the memory
where it remains readily available for
future transactions.
These memories take three common
forms: magnetic core, magnetic drum,
and magnetic tape. The rate at which
information is required in the computation determines which type of memory
is used. The types are listed in order of
{lecreasing accessibility. The core is the
"fastest" memory. The bits take the form
of a magnetized or unmagnetized core
to indicate respectively the "I" or "0."
The core memory immediately supplies
the number it contains as often as desired. The magnetic drum is a metal
-drum coated with magnetic oxide. The
bit is recorded as the presence or absence of magnetization in a particular
.area on the drum. The recording is done
by heads similar to tape recording heads.
<fhe drum rotates at a high rate of speed.
As the area passes under a fixed writehead a pulse is applied to magnetize or
·demagnetize the area as required. For
readout, another head is used to detect
the presence or absence of the signal as
the area passes.
The information on the drum is avail.a,ble only once pel' revolution thus its
"access time" is longer.
The tape storage is essentially the
s ame as the drum except that a reel of
tape is used. Some sort of searching
technique has to be used to find the area
-in which the information is found, thus
this is the slowest of the three methods
,described.
For such applications as missiles where
nigh speed calculations are necessary,
the core memory would be used. In the
cxample of a bank account, the tape
memory would probably be adequate.
The Ana log Computer
The analog computer operates, as its
name implies, by providing an analog of
some physical process. One of the best
examples of the analog computer is the
AUDIO
•
FEBRUARY, 1961
slide rule. On the slide rule numbers are
represented as lengths. The operations
of adding or subtracting of lengths accomplish various mathematical operations.
In its engineering form the analog
computer normally is used in the simulation of entire systems. While there are
mechanical, electromechanical and electrical analog computers, this discussion
will be confined to the electrical type.
In setting up an analog simulation the
equations which represent the behavior
of the actual physical system should be
available. Electrical circuits are then
made up which obey the same type or
class of equations. Voltage and current
variables within the electrical circuits
to a piston which is immersed in a cylinder of oil. The piston has holes in it to
allow the oil to flow through. This pistoncylinder combination is a typical shock
absorber. What does the velocity of the
mass become when the pin is removed'
From experience it can be surmised that
the mass will fall with increasing velocity until the oil is going through the
piston holes as fast as it can. At this
time the mass will have its maximum
velocity and will keep this velocity until
tbe piston strikes the bottom of the cylinder. The velocity will take the form
shown in Fig. 2.
In order to set up an electrical analog
of this problem it is necessary to write
an equation of the system. Using conventional laws of mechanics this equation is:
l\ix - W + KdX = ~ Forces on
mass = 0
(1)
where
M = Mass of the body
W =Weight of the body =Mg
Kd = Damping coefficient due to the oil
=Acceleration of the mass
x =Velocity of the mass
g = Gravity acceleration
solving for x and substituting ,lVIg for
W yields:
(2)
x
X
Zr
Z,
'n
Fig . 5. Gene ral summation .
will behave in the same manner as do
the variables of the physical system.
Changing resistors, capacitors, and
voltages in the electrical circuit will then
correspond to changing various physical
parameters; mass, spring force, or
Imgth, for example. By making these
circuit changes the engineer can easily
optimize his design. 'l'he final circuit
quantities can then be related back to
the physical parameters.
The types of problem which are appropriate for an analog computer include aircraft simulation (of which the
"Link Trainer" is a classic example),
atomic reactel' control, automobile suspension systems, and power transmission
systems.
In order to show the theory of the
analog' computer it is necessary to have
a problem. For the present, the problem
to be discussed is that shown in Fig. l.
A mass is raised above some reference
and held by a pin . 'fhe mass is connected
.,
K'1
x=g-M
N ow if an electrical circuit can be determined which obeys an equation of the
same form the analog is found.
Using "20-20 hindsight" consider the
circuit of Fig . 3. Writing the charge expression for the voltage drops around
this loop when Sl is closed we find equation 3,
· lq
E 0= R q+C
(3)
,,-here q is the current and q is the charge.
Solving for q yields:
q= Eo _~
R
RC
(4)
This equation is of the same form as
equation 2. As X, the acceleration, is
the time rate of change of X, the velocity,
so is q, the current, the time rate of
change of q, the charge.
The analog relationships of the quantities are given below with constants inserted to conserve units.
feet/second 2
[k x ]
= coulomb/second
(5a)
Fi g. 6 . Adder symbol.
23
lel'e [k x 1 =
WI
feet/second
coulomb
(5b)
2
g = k . EOwhere [k 1 = feet/second
g R
g
coulomb/second
( 5 c)
K
1
l/second
M = k t RC where [ktl = l/second
1
(5d)
The small k constants are known as
scale factors and as seen by their units
are used to relate the various quantities
of the actual and the analog system, kt,
is seen to be nondimensional. The numerical value of these scale factors depend on the expected range of the various variables.
It can be seen that the act of closing
SI in the electrical circuit is the same
as the act of pulling the pin in the actual
system . Further, it is evident that the
actual system can be optimized by
changing the electrical quantities until
the desired operation is achieved. Then
by using the scale factors the values of
the actual system parameters that will
cause the same response are established.
In analog computer work the basic
building block is the operational amplifier. Through the use of RC networks in
conjunction with the amplifier various
mathematical operations can be formed.
The symbol most commonly used for
the operational amplifier is given in (A)
of Fig. 4. In (B) of that figUl'e this amplifier is shown with an input impedance,
Zh a feedback impedance, Zi' and a grid
impedance, Zg. The amplifier gain is G.
The input voltage is ei> the grid voltage
eg, and the output voltage is eo. An
expression for the output voltage eo will
now be found by using Kirchoff's rule
that the sum of the CUl'rent into the grid
point is zero. This leads to the expression
can take various forms of RC networks
giving a large variety of functional relationships between the input and the
output voltages. These relationships are
useful in complex problems.
The most co=on forms in use are the
adder and the integrator. If more than
one input impedance is added to the grid
point as shown in Fig. 5, the output voltage will be the sum of all the inputs with
gains determined by the impedance
ratios as shown in equation 11.
eo = -
( Z~ ell + Z~~i2
i1
12
+ . .. . + Zrin ) (11)
In
This addition applies regardless of the
form of the impedance. If the imped-
Fig. 7. Pote ntiom eter ga in ad justmen t.
Fig. 8. Integra tor o perational amp lifie r.
Fig. 9 . Integra tor symbo l.
The relation of the grid voltage to the
output is given by:
(7)
By combining equation 6 and equation 8 the output over input relation
becomes:
Zf (
Zi Zf)
eo =_ Zf _ Zj 1 + Zf+ Zg
ej
Zj
G
(9)
It is seen that if G is made very large,
the second term vanishes leaving:
eo
Zt
el =- Zi
(10)
This is the basic expression for use in
analog computer work. The impedances
24
eo
ei
=_ Zf = _ _1_=_~('~) =_~ (12)
Zj
RjroC
RC S
In LaPlace notation the
S
~
signifies
integration. A simple intuitive approach
is given to show that this circuit does
integrate. From equation 6 the CUl'rents
into the grid point equal zero. Then if
el is providing current, ~, a current of
(6)
(8)
gain, kIa, where "kl " is the ratio of Ra
to Rn + R b , and "a" is the ratio of R f
to R i .
The integrator is shown in Fig. 8. In
this case the feedback impedance is a
capacitor. The relation from ei to eo becomes :
Fig . 10. Spring, mass, da m pe r syste m.
ances are resistors, the unit is an adder.
For simplicity the adder is shown in
Fig. 6 where gains a, b, and c are the
respective ratio of the input and ou tput
impedances. (In this figUl'e and from
now on all voltages are with respect to
ground.)
Potentiometers can be used to obta in
gain values. The input voltage, if fed
into a potentiometer, will appear at the
arm with a gain between 0 and 1 depending On the potentiometer setting.
Thus, in Fig. 7 the input voltage appears
at the amplifier output with the overall
equal magnitude must be flowing in the
capacitor. This is possible only if the
voltage across the capacitor is constantly
changing. For a constant ei the output
eo is then constantly increasing. This is
integration. If ei is removed, eo will remain constant. For simplicity the integrator is given the symbol shown in
Fig. 9.
The discussion of the integrator immediately leads to an analogy. If eo is
considered in a particular problem to be
the position of a body, then el is the
velocity of the body. The relation, again
using LaPlace notation, is expressed by:
ei = - kl Seo
(13)
For this expression the S signifies differentiation. By the same reasoning the
acceleration, which can be denoted by
ea is :
ea = - k2 Sei = + kl k2 S 2eo
(14)
The minus sign is associated with the
minus gain of the amplifier. That is, a
positive voltage at the input causes a
negative voltage at the output. This r eversal of sign is an important point to
remember in setting up a system simulation.
In physical systems one r elation a ppears more often than any other. This is
the so-called "quadratic" response. The
response of a spring, mass, shock absorber system as shown in F i g. 10 is of
this type. The expression for this system
response to an input F (t) is:
Mx+Kdx+Ksx= F(t)
(15)
This expression states that the input
force is balanced by the acceleration,
velocity, and displacement forces of the
mass.
If LaPlace notation is used the expression becomes:
M S2x + Kd Sx+Ksx=F(S)
(16)
which rearranges to:
x
I/K.
(17)
=
F(S) M S - Kd S 1
--+ +
K s Ks
(Continued on page 83)
AUDIO
•
FEBRUARY, 1961
Popular E-V "664" Cardioid Dynamic Microphone Brings Broadcast Quality to General Sound Applications
Like the precision-ground lens of a fine camera, the high-fidelity Model
664 cardioid dynamic "sees" and transmits a faithful replica of realityneither adding nor subtracting, without coloration or distortion. Through
its smooth response, wide range, and rejection of unwanted sound,
public address technicians, radio amateurs, and tape recorder owners
can now obtain the accurate, natural sound pick-up that was once the
exclusi"e property of the broadcast engineer.
Utilizing the exclusive Electro-Voice Variable-D ® principle, the "664"
features highly directional sound selectivity; reduces pick-up of reverberation and ambient noise up to 50%. This E-V patent set an entirely new
standard for directional microphones and no directional microphone
without Variable-D can match its performance characteristics. These
characteristics allow its use at greater working distances and provide
needed feed-back protection . Response is smooth and peak-free over a
broad 40 to 15,000 cps range. Placement and handling is non-critical.
A single moving element-the indestructible E-V Acoustalloy® diaphragm-withstands high humidity, temperature extremes, corrosive
effects of salt air, and severe mechanical shocks. The 664 is sturdily
constructed, inside and out, assuring a long, trouble-free life of dependable service.
Other Features : Output-55 db. On-off switch . Impedance 150 ohms and Hi-Z. (impedance may be changed by moving one wire in
MC-4 cable con nector) . Pressure-cast case. Chrome finish. Cable length 18 feet . Size 7% inches long, less stand coupler. Diameter
1y, inches. Net weight 1 lb ., 10 oz. List Price . .. $85.00. With Gold Finish . .. $99.00. (Regular Trade Discoun ts Apply on All List Prices.)
Commercial Products Division
ELECTRO-VOICE, INC.
®Patent Pending
Dept. 2A Buchanan, Michigan
,"
Characteristics of Tape Noise
WI LLiAM B. SNOW:::
Tape noise is a fundamental limitation in all recording processes.
Here are some criteria for judging a tape recorder with respect to noise.
limitation in
all recording processes. Unless a
low noise level is achieved, true
high-fidelity sound reproduction is impossible because low passages will be
heard against a background of interfering and unwanted sounds. Low noise
level with consequent wide dynamic
range is a characteristic of modern magnetic tape recording
OISE IS A FUNDAM.ENTAL
N
Signal-te-Noise Ratio
Signal-to-noise ratio in magnetic tape
recorders is ordinarily expressed as the
ratio of rms single-freq uency signal at
the level yielding 3 per cent harmonic
distortion, to total noise measured over
the complete reproducing frequency
range. The 3 per cent point represents
the maximum permissible recording level
for signal peak amplitudes, and is usually measured at 250 cps.
When the signal-to-noise ratio is expressed as a single number in this manner for magnetic tape recorders, it essentially represents a signal-to-hum ratio.
Hum reduction is particularly difficult
with tape recorder s because the magnetic
reproducing head must be mounted near
motors and power transformers which
produce magnetic fields from which the
head must be shielded. In addition, t he
playback equalization for magnetIc re-
* COn8ultilng Engilneer, Santa Monica,
California.
~
Tape Noise Frequency Analysis
First. a portion of tape containing a
250-cps tone recorded at maximum level
was reproduced to give a reference output reading. Then, erased tape was reproduced without alteration of the playback amplifier gain while noise output
was measured through the electrical filters of two types of frequency analyzer.
Figwre 1 shows the results of the noise
measurements made with a narrow band
(25 cps) and an octave band analyzer.
The usual signal-to-noise ratio described
above is shown by the line at "Over-all"
to be 52 db. With the octave filters, noisc
was checked for three conditions: tape
erased in the machine (Curve A), bulkerased tape (Curve B) and tape stopped
showing only playback amplifier noise
(Curve C) .
It can be seen that the over-all level
is mostly accounted for by the noise in
the two lowest octave bands. Above 300
cps the levels are much lower. At low
frequencies two sets of "spikes" are
shown, measured with the 25-cps band
analyzer which could separate the indi-
~~ 1 1I 11m-~~~~~~ffi-~
50
y
OVER-ALL
I
~~
'~
C~mparison
With Room Noise
It is important to the success of magnetic recording that the signal-to-noise
ratio at higher frequencies is much
greater than the usual single number
discussed above. The octave-band levels
are roughly constant and are about 75
db below the standard 3 per cent distortion level. Figure 2 has been prepared to
explam the significance of this. Rather
than ratios, this figure shows actual
sound levels as measured in a room with
a sound level meter and analyzer. They
have been p lotted in the special form of
"masking level"; that is, the level which
noise from the reproducing system must
attain if it is to be detected in the presence of the room noise. If it falls below
(Oontinued on page 82 )
60
,.--,--.,....,.,II,......,..I~
1 1 1I.----..........,......,.......,..,..,n-r---.....---r'TT"'T"T~___,
50
1_
oj
~
~ 1160 1---+--+--HH-+++lIl~
;1. :~-H--+--+l
~' rr1
vidual hum components. The noise in the
two lowest octave bands is contributed
almost entirely by the hum components,
60 and 120 cps, and is essentially unchanged when the tape is stopped.
Above 200 cps, however, the noise comes
principally from the tape, and residual
electrical noise (Curve C) is negligible
in comparison to it. The amplifier has
the capability of p laying much quieter
tapes in the future as they are developed.
Small difference between noise for bulkerased and machine-erased tape indicates
good balance in the erase oscillator.
cording necessitates maximum gain at
low frequencies. It was felt that a somewhat detailed examination of the noise
from a tape recorder would be of interest. A Movicorder tape recorder was employed operating at a speed of 7.5 inches
per second.
U II
(2)
1)
III II
60
cp~s_-
-Jj- +_IH-+-I-+Il--I-- I+--++++tlI-tH-----i
01 20 cps
(2) OCTAVE BAN D LEVEL S H-1I+H-- - l
~
I
;~ 70 ~-+--+-41~++~~:-,~~~~
~H-~~-A-++---H-b~~~--4
«0
I
0'"
I
t; 0
I
\
r!_-~ ~80~-+--+-~++~~I~~IH--I-~+~+--2~~HH-++*~~~
3~
I
T'"
I
2 90 ~_+__+_~++~~I~~I~I++T+H+~4~~·~,c~~~~v~~~~~
~
z
t--t-
I
I
I :
(1 ) N ARROW BAND LE VELS
Uli 1II IIIi
-HHtI--I-- I+----+-H++II-+H- --/
lill 1'1 'II I
l 00,:·~~·~
' ~
· ~~IOO
~~~~~~'-·~~I~
_--~~~~L
, ~·A+,~
OOOO
L-~
'OOOO
FREa U ENCY IN CYC LES PER SECON D
100
FREOUENCY
1000
IN
CYCLES PE R
10000
'0000
SECON D
Fig . 1. (l eft) Results of noise measurem e nts on a typical re cord er. Fig . 2 . (right) Re co rder noise compare d to room background
noise for typical quie t roo m. Above 200 cps shown as octave bands; be low 200 cps s hown as single ton e s.
26
AUDIO
•
FEBRUARY, 1961
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Understanding the Tape
Oscillator
Incorrect bias can increase distortion, reduce the amount of signal recorded, and also decrease high frequency response. Here is an explanation of biasing which will answer many questions as to how and why.
HERMAN BURSTEIN AND HENRY C. POLLAK':'
ONE RESPECT-the oscillator
-do tape amplifier circuits differ
radically from the circuits normally found in control and power amplifiers. Otherwise, the tape amplifier
employs similar means for the similar
tasks of amplifying signals, controlling
gain, shaping frequency r esponse (equalization), minimizing noise and hum, and
performing various switching functions.
Accordingly, the technician or audiofan conversant with audio amplifier
circuits should not find tape electronics
presenting essentially different problems,
except for the oscillator. Therefore it is
the purpose of this article to provide a
basic understanding of the oscillator
circuits commonly found in tape r ecorders. Such an understanding will facilitate the work of the individual seeking to restore a tape oscillator to correct
operation, to improve its performance,
or to build a tape amplifier capable of
recording satisfactorily.
O
NLY IN
such as tape duplicators, where erase is
not required, current is supplied only to
the record head.
Bias current in the record head serves
two vital purposes. It increases the
amount of signal recorded on the tape.
It reduces distortion. Unfortunately, as
bias current is increased above a certain point, high frequency response
deteriorates. H ence one must guard not
only against insufficient bias current,
which results in excessive distortion and
poor signal-to-noise ratio, but also
against too much bias current, which
produces severe treble losses. The slower
the tape speed, the greater are these
high-frequency losses.
Bias current requirements of record
heads are usually quite modest, on the
order of 1 ma for many heads. In con-
Functions of the Oscillator
The oscillator operates only when the
tape recorder is in the record mode and
supplies high-frequency current, also
known as bias current, to the record
and erase heads. The frequency is usually
between 40,000 and 100,000 cps. In a
few recorders employing a permanent
magnet for erase or in special machines
* Authors of "Elements of Tape Recorder Circuits," Gernsback Library.
28
Fig. 1. Single-ended oscillator employing
plate-to-grid feedback.
trast, erase heads require a good deal
more current in order to perform effectively. A typical erase head may
require from 15 rna upwards.
Oscillator Operation
Most oscillators employed in tape recorders operate by applying positive
feedback between appropriate tube elements, usually between plate and grid,
in an amount sufficient to sustain oscillations in a tuned circuit consisting of a
coil and capacitor. The values of the
coil and capacitor essentially determine
the frequency of oscillation.
The operation of a tuned-circuit oscillator is a complex process, with many
things happening at once. A complete
description requires tracing over one
cycle of oscillation the phase relationships between voltage and current in
electromagnetic and electrostatic fields
and in a -tube circuit. Instead of going
through such an analysis, this article
will attempt to provide a simpler, basic
insight into how an oscillator works.
A fundamental explanation can be
based around Fig. 1) a simple oscillator
similar to that actually found in many
moderate-price tape recorders. To understand why oscillation takes place, it is
helpful to consider fu·st just the tuned
circuit, comprising C1 and L1. Assume
that for some reason the upper plate of
C1 is charged, that is, contains more
(Continued on page 32)
AUDIO
•
FEBRUARY, 1961
number five
FOR A LIMITED
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TAPE GUIDE
GRID - LEAK RESISTOR,
GRID- LEAK
([1'om page 28)
electrons than the lower plate. Seeking
equilibrium, electrons tend to flow from
the upper to the lower plate through the
path afforded by L1. This flow creates
an electromagnetic field about the coil
and, by Lenz's Law, induces a voltage
across the coil of a polarity such as to
prevent electrons from flowing rapidly
through the coil. Thus the electron flow
gmdually reaches a maximum and then
starts to slow down as the charges on
the upper and lower plates approach
equilibrium. However, when the rate of
discharge of electrons from the upper to
the lower plate begins to slow down, the
field of Ll begins to collapse. By Lenz's
Law, a voltage is again induced which
opposes the change in electron flow
through the coil. Thus the collapsing
electromagnetic field promotes the continued flow of electrons from the upper
to the lower plate. In this manner the
lower plate collects not just enough
electrons to restore equilibrium with respect to the upper plate (zero voltage
across the capacitor) ; rathel', it accumulates an excess of electrons compared
with the upper plate.
Eventually the coil's field has fully
collapsed so that no more electrons arrive at the lower plate. Now this plate
has an excess of electrons; in other
words, the capacitor has an electrostatic
field, which is the counterpart of · the
coil's electromagnetic field. Therefore,
electrons begin to flow from the lower to
the upper plate through the coil. As
before, an electromagnetic field is built
up around Ll and, when this field collapses, it results in the continued accumulation of electrons on the upper
plate of Gl, so that the original state of
matters is restored: an excess of electrons exists on the upper plate. This
completes one cycle of oscillation.
Assuming no resistance in the coil and
no load, the tuned circuit produces a
perfect sine wave, eminently desirable
for tape recording purposes to achieve a
minimum of noise. In practice, this is,
of course, impossible; some distortion is
always present. However, oscillator
waveform distortion and resulting noise
are kept to negligible quantities in highquality tape recorders.
The frequency of oscillation-or the
time requiTed for one cycle-essentially
depends upon the values of Ll and Gl;
to some extent it is also governed by
the slight amounts of inductance and
capacitance found in the tube and other
components associated with the tuned
circuit. The coil and capacitor values, in
conjunct'ion with each other, determine
how long it takes for the electromagnetic field of Ll to build up and die
32
BIAS AN D
ERASE
CURREi--n
_ ·n .......-+--I
Fig . 2. Sin g le-end ed osci lla tor e m p loy ing
cathode-to-gr id fee dba ck .
away and for the electrostatic field of
Gl to do the same. The larger the inductance of Ll, the longer its field takes
to grow and fall. Similarly, the larger
the capacitance, the longer it takes to
discharge electrons from one plate to the
other. At the oscillation frequency, the
charge 01' discharge rates of the two
components are equal, and they work in
unison: the electromagnetic field stores
energy for the same pel'iod that the capacitor is able to deliver it, and in turn
the capacitor stores enel'gy for the
same period that the coil is able to deliver it.
Another way to appreciate why a
circuit such as Fig . 1 oscillates at one
particular frequency is to consider the
impedance between the plate side of the
tuned circuit and ground. (It should be
recognized that the bottom of the tuned
circuit is effectively at ground so far as
a.c. is concerned because of the filter
capacitor associated with B-plus.) Maximum impedance of the tuned circuit
occurs at the frequency where the reactances of Ll and G1 are equal. For any
other frequency, the impedance is less,
S0 that either the coil 01' capacitor tends
to serve as a shunt to ground. Consequently, alternating current developed
through oscillation tends to be shunted
to ground except at the frequency where
impedance is maximum .
Once started, oscillation in a tuned
circuit would theoretically continue forever were it not for various losses, inAUDIO
OUTPUT ..........
TRANSFORMER'
B+ _ -----'
BIASAN
~
ERASE
CURRENT
Fig . 3. Use of t he a udio output t u be as
an oscillctor in t he record mode.
cluding those due to coil resistance, capacitor leakage, and the load presented
by the tape recorder heads and other
circuit elements. For oscillation to be
sustained, the tuned circuit needs outside aid. This is similar to the child on a
swing, who keeps moving as the result
of a moderate systematic push from
someone on the ground.
The tuned circuit receives systematic
aid from the tube circuit with which it is
associated. When the upper plate of Gl
is to be charged, matters are arranged so
that tube current increases, thereby sending more electrons to this plate. Conversely, when the lower plate of Gl is
being charged, tube current decreases,
sending more electrons to this plate
(from the viewpoint of a.c., a decrease
in tube current is in effect a flow of
electrons from B-plus toward the tube).
The purpose of L2 in Fig. 1 is to vary
the grid voltage in a manner which
causes tube current to assist the oscillation process. The changing electromagnetic field of Ll cuts across L2 and,
by transformer action, induces a voltage
across L2- that is, between grid and
ground. The windings of L2 are so connected to grid and ground that when
tube current is increasing the grid end
of L2 goes positive, which causes a
further increase in tube current. This of
course is positive feedback. Similarly,
when tube current is decreasing, the
grid goes negative, resulting in a further
reduction in tube current.
The cumulative increase or decrease
in tube current which takes place due to
positive feedback approaches an end
when the charge on either plate of Gl
approaches maximum. There is a slowing
collapse of the magnetic field around Ll
and eventual reversal of this field as Gl
approaches maximum charge and then
begins to discharge. This results, through
transformer action, in a decrease in grid
voltage (positive or negative as the case
may be) and eventual reversal of grid
polarity.
Though belated, an explanation of
how oscillation gets started is now appropriate. Assuming that B-plus has
been applied to the circuit and current
supplied to the tube heater, initially
there is zero voltage between grid and
cathode. Due to the random motion 'of
electrons emitted from the cathode, a
minute voltage will appear at the grid.
Assume that at a given instant this voltage is positive-going. Therefore the current through the tube increases. This
increase in tube current results in a
charge on Gl, a change in the electromagnetic field of Ll, positive feedback
at the grid, a further increase in tube
current- and the process of oscillation is
on, as already described.
Grid-Le ak Bias
The purpose of grid resistor Rand
AUD IO
•
FEBRUARY, 196 1
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AUDIO
•
FEBRUARY, 1961
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33
grid capacitor C~ in Fig. 1 is to provide coupling between LI and L~) thus limitthe oscillator tube with the requil'ed ing the voltage fed back to the gTid.
negative gTid bias. The amount of grid
bias depends upon the magnitude of Oscillator Variations
oscillation needed-within the tube's
There are several variations of the
capabilities. When the grid goes posi- single-ended oscillator of Fig. 1. In a
tive and draws current, the resulting popular variation, the oscillator coil is
electron flow charges the top of the ca- in the grid-cathode circuit, as in Fig. 2.
pacitor. The only path for the capacitor For positive feedback to occur here, it is
to discharge through is the grid resistor. necessary that the grid go positive relaAs electrons leak slowly from top to tive to the cathode when tube current inbottom of the capacitor through the re- creases, and negative when current desistor, this flow causes a negative d.c. creases. Positive gTid-cathode voltage,
voltage to appear at the top of the re- in turn increases tube current, and negasistor. This voltage al:3o appears at the tive grid-cathode voltage decreases it.
control grid.
The cumulative buildup or decrease in
The negative grid-leak bias reduces tube current is controlled by the tuned
the transconductance (gm) of the tube, circuit so as to sustain oscillation.
and thereby the gain around the comAssume that the current flowing from
plete oscillation loop. If the loop gain is ground through the lower part of oscilgreater than 1, as it must be for oscilla- lator coil L and then through the tube is
tion to start, the amplitude of each suc- momentarily increasing. This increasing
cessive oscillation will be greater than current induces a voltage across the
the previous one. This causes the grid to grid-ground portion of the coil such as
swing more into the grid current region to oppose the increase. That is, the inon each positive half cycle, resulting in ductive reactance of the coil causes a
more grid-leak bias. But the bias affects voltage drop across it, causing the
the transconductance markedly; the
greater the negative bias, the lower the
gm' So each positive grid swing results
in added negative bias, reducing the gm,
and hence the gain, until the loop gain is
exactly 1. The amplitude of the oscillations will remain at this value very
closely.
The self-regulation of the grid-leak
bias system is not perfect, but is sufficient to make the oscillator relatively
insensitive to line voltage variations,
changes due to normal heating of the
Fig . 4. Typical push-pull oscillator.
components, and tube aging.
The grid capacitor loses some of its cathode end to go positive with respect
charge during every cycle, but unless the to the ground end. By autotransformer
oscillations are getting smaller, each action, the positive-going voltage at the
positive grid swing recharges the ca- cathode appears as a still more positive
pacitor, thus maintaining the bias volt- voltage at the grid, causing a further
age. The time constant of the grid-leak increase in tube current. Thus, as in Fig.
capacitor and grid resistor. (product of 1, positive feedback is present. The voltR times C~) determines how long the age between grid and ground causes cacapacitor can discharge through the re- pacitor C to charge, making the grid-end
sistor before the voltage has dropped , positive and the ground-end negative.
appreciably. This time constant should Since the tube CUl'l'ent cannot increase
be about 5 to 10 times the period of one without limit, the tube current eventually
cycle of oscillation to maintain grid bias reaches a maximum, that is, a steady
adequately. For example, if the oscil- value. As a result, there is no longer an
lato): frequency is 50,000 cycles per sec- induced voltage due to tube current
ond, one cycle is 1/50,000 second, or 20 increasing. Consequently the grid-tomicroseconds (Ilsec); 10 times this ground voltage decreases and capacitor
amount is 200 -Ilsec. The time constant of C discharges upward through the coil.
the 100,000 ohm resistor and .002 microAs the grid-to-ground voltage defarad capacitor in Fig. 1 is 200 Ilsec.
creases, the grid-to-cathode voltage deAlthough grid-leak bias keeps the creases and so does the tube current.
amplitude of oscillations from being ex- This induces a voltage in the lower portremely great, it is very desirable also tion of the coil, this time negative at the
that feedback be limited so that the tube top and positive at the ground end. As
operates within the linear portion of its before, autotransformer action causes
characteristic in order to maintain an the grid to go more negative with respect
oscillation waveform with minimum har- to the cathode, further reducing tube
monic distortion. In the case of Fig. 1, current, making the grid still more negfeedback is controlled by using a proper ative, and thus assisting the upper plate
ratio of turns and the right amount of of the capacitor to go negative with
34
respect to the lower plate. It should be
kept in mind that the process of positive
feedback and the turning points from
increasing to decreasing tube current
are under control of the tuned circuit,
which determines the rate of increase and
decrease in tube current and thus the
frequency of oscillation.
Finally, it may be pointed out that
while the locations of the grid-leak resistor and capacitor are different in Fig.
2 than in Fig. 1, the action is exactly
the same.
Double-Purpose Oscillator
The majority of moderate-priced tape
recorders contain a small speaker and a
power amplifier, usually single-ended,
for playback purposes. As a measure of
economy, a number of these machines
convert the audio output tube to an
oscillator in the record mode. In a few
instances, a similar double function is
served by other tubes. For example, in
one recorder the playback input stage
becomes an oscillator when recording.
Figu1'e 3 shows a circuit in which the
audio output tube doubles as an oscillator. LI and L2 constitute the oscillator
coil, providing plate-to-grid feedback.
The primary of the audio output transformer is in series with L 1 • Capacitor
C~ across the output transformer primary offers a low-reactance path at the
oscillator frequency between the plate of
the tube and the primary of the oscillator coil. Similarly, LI of the oscillator
coil offers a low-reactance path at audio
frequencies between B-plus and L s) the
output transformer primary.
Push-Pull Oscillators
The great majority of professional
and semi-professional tape recorders and
a fair number of moderate-price ones
employ a push-pull oscillator, customarily using the two halves of a dual
triode such as a 12AU7 or 12BH7. While
one triode is in the positive half of its
oscillation cycle, the other is in the negative half. Thus, symmetrical forces are
at work, reducing even-harmonic distortion. Distortion in the bias waveform
is a source of noise. The greater the demands upon the oscillator to provide
enough current for adequate erasure, the
greater is the likelihood of distortion.
Because of its lower distortion for the
same output, the push-pull oscillator is
favored.
Figure 4 shows a typical push-pull oscillator. Feedback is from the plate of
VI to the grid of V~ through capacitor
C~j and from the plate of V~ to the grid
of VI through capacitor Cs) C1) as well
as C~ and CS) together with coil L essentially determine the resonant frequency.
Assume the grid of V I is positivegoing at a given instant. This produces a
(Continued on page 82)
AUDIO
•
FEBRUARY, 1961
The SONY/SUPERSCOPE commitment to perfection has led to revolutionary achievements in the
audio electronics field. The STERECORDER 300, for example, is unquestionably the most versatile,
perfectly performing stereo tape recorder on the market today.
The Sony-developed gold membrane in the C-37A Condenser Microphone is another example of
.
Sony superiority.
The 262-SL sound-with-sound tape recorder at $199.50, the 262-D four track stereo recording and playback
tape transport at $89.50, the 101 transistorized dual track monophonic recorder at $99.50, and the many
other Sony/Superscope products are all remarkable achievements; the inevitable results of Sony/Superscope's
commitment to engineering perfection.
For literature, or the name of your nearest franchised dealer, write: Superscope, Inc., Dept. 2,
Sun Valley, California.
.
SONY ~
AUDIO
•
FEBRUARY, '1961
fl."
((,pC/elll/t"St,'"',,
SUPERSCOPE INC., SUN VALLEY, CALIFORNIA
35
Loudspeaker Design
Converting the electronic "message" from the amplifier into sound requires the
loudspeaker to undergo physical contortions which may, or may not, distort the
message. Understanding the fundamentals of achieving "distortionless contortions" may help in selecting the loudspeaker best suited to your requirements.
NORMAN H. CROWHURST *
an article on how to design a loudspeaker. For one thing,
very few readers are likely to have
the opportunity of designing their own
loudspeaker. On the other hand, anyone
pursuing audio as a hobby is interested
in good reproduction and hence is concerned in getting a good loudspeaker.
In this connection, many are wanting to
know "what the score is" about the different ways of designing a loudspeaker
system. This is because the fact still remains that the loudspeaker is the weakest link in the reproducing chain and
because of the divergence of design approaches used in the products available
in this field.
To clarify this matter we will explain
some of the simple principles of loudspeaker design, so that those interested
can better understand how different approaclles to the problem attempt to
achieve their objective. The aim of' any
system, of course, is to convert the electrical energy delivered by the amplifier
into acoustical energy in the room, with
the greatest degree of fidelity possible.
We would like to have sound waves
whose pressure variations are directly
proportional to the voltage variations
at the output of the amplifier, regardless
of the frequency and amplitude of the
fluctuations. Unfortunately, however, to
date there is no direct means that is
commercially p ractical, of transferring
electrical energy into acoustical (lnergy
Without going through some mechanical
medium. The nearest practical approach
to this is an electrostatic loudspeaker.
But this has to · have a diaphragm to
transform the electrical force between
its plates into mechanical movement of
the air.
T
HIS IS NOT
* 216-18 40th Ave., Bayside, N. Y.
Table 1
Mechanical
system
Force
Velocity
Electrical
system
Pressure
Volume movement
Volume disDisplacement Charge
placement
Resistance Viscous action
Friction Mass
Inductance Air mass
Compliance Capacitance Air compliance
Lever
Transformer Change in area
36
Voltage
Current
Acoustical
system
The more conventional dynamic type
loudspeaker Ui;;es a voice coil, the currents in which ,produce mechanical force,
which in turn drives the diaphragm, and
the diaphragm, by contact with the air,
produces movement in the form of
sound waves. So we have two transfers
of energy to think about, electro-mechanical from the voice coil to the diaphragm, and mechanical-acoustical from
the diaphragm to the atmosphere.
column gives the equivalent electrical
quantity in the analogy, while the right
hand column gives the acoustical quantity that corresponds.
In this system of analogy we make
force equivalent to voltage, but this does
not say we can convert force into voltage in an electro-mechanical transducer.
If we use an electrostatic device, it is
true that the electrical voltage produces
a deflection force on the diaphragm, but
when we use a dynamic device, such as
t
WAVES IN
ROPE
Fig. 1. Showing the manner in which transverse waves are set up in the cone or
diaphragm of a loudspeaker: (a) a section through the voice coil and diaphragm;
(b) an analogous form of wave propagation.
The Use of Analogies
A great help in understanding what
happens is the use of analogies. When
we start to learn about electricity, we
often use analogies, from mechanical or
other spheres, to help to explain the
behavior of electricity. Now that elec-
honic circuits have progressed so far,
and the general understanding of them
improved so well, it is often helpful to
r everse the procedure and use electrical
circuits as analogies for mechanical or
acoustical behavior.
An important thing to realize is that
an analogy is only a convenient parallel
way of thinking. It does not express
identity, nor does it relate quantities
that can be transformed dl'rectly from
one to another.
Table 1 lists the more conventional
analogies used. The left hand column
gives the mechanical quantity, the center
a moving coil loudspeaker, a different
transfer takes place; it is current that
is responsible for producing driving
force in the coil former; movement of
the coil former in turn produces voltage.
So if we were to use the direct transference that occurs in a moving coil
transducer, we should reverse the order
of the analogy and make current correspond with force and voltage with movement. On the other hand, in the electrostatic transducer, it is the voltage that
produces force on the diaphragm; while
movement of the diaphragm causes
charge to flow in or out of the transducer
in the form of current. To avoid confusing the issue, we will only use the one
analogy.
.
.
Following the analogies down, they
are fairly simple to follow; mechanical
friction corresponds with resistance.
This is evident because both are responsible for the dissipation of energy in
their respective systems.
AUDIO
•
FEBRUARY, 1961
High Fidelity's Ultimate Standard.'
ILLUSION
The term high fidelity
has been used so freely
that its literal meaning
is often forgotten. It
does not refer to overloud, over-resonant,
over-brilliant sound,
but to the faithful recreation of a musical
performance.
The ultimate test of a
high fidelity system,
then, is a direct comparison with the sound
of the original instruments.
The moment of transition from live to recorded sound: AR-3 speakers and Dynakit amplifiers
take over from the Fine Arts Quartet.
Such a comparison was made during the recent hi-fi show .in New York City, when AR speakers and Dynakit
amplifiers vied with the Fine Arts Quartet in a "live vs. recorded" concert. At intervals the Quartet stopped playing and allowed the hi-fi system to take over, using pre-recorded sections of the music, without missing a beat.
McProud, editor of Audio, reported: "We must admit that we couldn't tell when it was live and when it wasn't."
The Herald Tribune referred to "awesome fidelity". Record reviewer Canby wrote: "My eyes told me one thing,
my ears another." Freas, audio editor of High Fidelity, wrote: "Few could separate the live from the recorded
portions."
After all of the trade jargon and esoteric talk heard at .hi-fi shows, this was the real thing.
DYNAKIT MARK HI AMPLIFIERS AND STEREO PREAMP, AND
ACOUSTIC RESEARCH AR·3 LOUDSPEAKERS, components designed for
the home, created the illusion. Although these components are medium priced,o they are widely regarded as
representing the highest qualtty that the present state of the art makes possible.
Further information on these products, including a list of high fidelity dealers in your area who carry and demonstrate them, is available for the asking.
o A complete high fidelity record playing system using the above components would cost
about $750. You may hear AR speakers and Dynakit amplifiers together (in these and other,
less expensive models) at AR Music Rooms, on the west balcony of Grand Central Terminal
in New York City, and at 52 Brattle Street in Cambridge, Massachusetts.
ACOUSTIC RESEARCH, INC.,
DYNACO, INC.,
AUDIO
•
24 Thorndike Street,
3912 Powelton Avenue,
FEBRUARY, 1961
Cambridge 41, Massachusetts
Philadelphia 4, Pennsylvania
37
Mass corresponds with inductance :
the mass or weight of a moving object,
which is called its inertia, tends to continue its course of movement until a
force is applied to change it. Force is
needed to start the movement, and again
to stop it. In electrical circuits, using
the analogy, this is the characteristic of
inductance where the current tends to be
steady and has to have a voltage applied
in order to change it.
A compliance corresponds with a capacitance : application of a force produces a deflection or displacement in the
compliance that will remain until the
force is removed, the same as application of a voltage produces a charge on
the capacitance. When the pressure on
a compliance is changed, the mechanical
device moves. When a voltage on the
capacitance is changed, current flows in
or out of it.
In an electrical circuit a transformer
changes a combination of high voltage
with low current to a lower voltage with
higher cUlTent, or vice versa. It changes
the relationship between voltage and
current at which energy is transmitted.
In mechanics a lever enables a small
force with a large movement to produce
a large force with a small movement or
vice versa, thus performing a function
in mechanical circuitry similar to a
transformer in electrical circuitry.
the behavior of a loudspeaker. We have
a driving force from the voice coil, the
object of which is to produce a movement of the diaphragm for the purpose
of transmitting the energy to the air on
a uniform voltage-pressure basis. To
figure out an equivalent electrical circuit
for the mechanical action, we have to
think about what opposes the movement
due to the force supplied by the voice
coil.
This is equivalent to the impedance
presented to an electrical source voltage.
The current accepted by the impedance
is analogous to movement: the lower the
impedance, the greater the current; the
lower the mechanical impedance, the
greater the movement produced by a
given force. So if forces due to two
kinds of mechanical reaction are both
combining to oppose movement of the
voice coil, these two forces must be considered as equivalent to components of
impedance in series. The movement, corresponding to current, is common t o
both and the force that they produce,
due to their reaction, will be dependent
upon the movement.
Assume for the moment that the voice
coil with the diaphragm forms a rigid
assembly and the only forces that will
oppose its movement are due to the air
in contact with the two sides of it. These
two columns of air reflect as two im-
.
+ 10
..0
l'...
12
.,..,
0
1
5
0
~
~ -10
'"
-20
1/
f.
V
Ii
.A
ru ~~
~
V
TOO
1000
10000
FREQUENCY IN CYCL ES PER SECOND
Levers are not used very much in
modern loudspeakers. The only types in
which they have ever been used are the
moving iron and the crystal types. This
was because the driving force was produced by an extremely stiff device that
was capable of large forces with small
movement. The lever helped to get a
larger movement more suitable for driving the diaphragm. In other words, it
helped achieve mechanical matching.
The reason why levers are avoided in
the mechanical design of loudspeakers
is that they are .not so easy to design
with a wide frequency response as are
electrical transformers. A lever to operate equally well at all frequencies
from 20 to 20,000 cps is a very difficult
requirement to meet.
Electromechanical Part
Now let's see how the electromechanical analogy helps us in understanding
38
If!
rv
ZUUJO
Fig. 2. The effect
of the transve rse
waves in the diaphragm on t h e
frequency r espo ns e: the solid
curve repres e nts
incorrect termi na ti o n, w h i l e the
d otted o ne shows
what co rrect terminati o n in the
sur ro und does.
pedances in series from the mechanical
viewpoint. One due to the behavior of
the column in contact with the back of
the diaphragm, associated with the enclosure, and the other in contact with
the front, which usually radiates out
into the air. More -of this anon; meantime this is somewhat of an oversimplification, based on the assumption that
the voice coil is rigidly coupled to the
diaphragm.
This is not quite true. It is coupled
by material having certain mechanical
properties and that is what we want
to consider immediately. The diaphragm
is not completely rigid, so the center
part, attached to the voice coil, can move
in a manner somewhat different from the
outer periphery and the various other
parts of the diaphragm.
The easiest way to think of the transmission of movement from the voice coil,
applied at the inner periphery of a
loudspeaker diaphragm, to the outer
periphery is in terms of a mechanical
transmission line. The force applied is
approximately transverse. This is illustrated in F ig. 1. In our ideal conception
the diaphragm should move back and
forth as an entity with the voice coil,
but due to its mechanical compliance or
stiffness and its effective distributed
mass, in conjunction with the effect of
air in contact with its surfaces, it tends
to behave like a length of string or rope
when one end of it is waved to and f ro
sideways. The essential difference from
this analogy is that the length of string
is 1'elatively flexible, while the diaphragm is 1·elatively rigid. However,
the same kind of effect occurs to a
limited extent.
The transmission velocity or speed a t
which the wave travels outward from
the voice coil is similar to- or not ve1'y
different from-the speed of sound in
air which, in v ery round figures, is 1000
f eet per second. Using this figure, a
wavelength at 1000 cps occupies one
foot, which gives us a useful basis f or
considering when this transmission ef f ect could set up interference patterns.
At high frequencies, where the wavelength is shorter, the distance from the
voice coil to the periphery of the diaphragm becomes several wavelengths of
transversely propagated wave, so the
diaphragm can break up into patterns
due to the reflected wave (if any reflection occurs). This is the cause of the irregularity in frequency response toward
the top end of the frequency r ange of
most single unit loudspeakers.
Much of this can be smoothed out by
careful attention to the compliance of
the diaphragm surround-the crinkled
p art that allows it to move back and
forth freely at the periphery. Use of a
suitable impregnating compound possessing an appropriate combination of
compliance and viscosity, provides a terminating impedance in the mechanical
material of the surround which prevents
reflection and hence avoids the break-up
effect. This method of treatment will do
much toward flattening the upper end of
the loudspeaker frequency response.
Figure 2 shows this.
A difficulty arises in the fact that the
properties of most of these impregnating compounds change with aging, and
hence the upper frequency response deteriorates as the diaphragm gets older.
Attention to the compliance of the
spider or centering device attached to
the inner periphery of the diaphragm
will also assist in controlling the movement, although this is strictly at the
"sending end" of the transmission line
and appears merely as a series element
in the driving force.
If the loudspeaker is driven from an
amplifier with a high damping factor,
AUDIO
•
FEBRUARY, 1961
ALTEC 309A AM/FM
STEREO TUNER WITH
INTER·CHANNEL BALANCE
• Individual AM and FM ElectronRay Tuning Indicators.
• Softly illuminated Tuning Scale.
• Decorative platinum gold or
platinum pink control panels.
• Self,ventilating cabinet included
in price.
• Individual AM and FM Tuning
Controls operate on a flywheel for
smooth dialing.
• AM Loca I/Dista nt Switch pro·
vides Inter-Channel Balance under
varying conditions.
• Automatic Frequency Control
(On/Off) provides positive station
lock·in.
• 5·position Functions Switch for
all stereo and mono requirements.
• FM Sq uelch Control with On/
Off option provides inter·station
silencing while tuning.
ALTEC 309A AM/FM STEREO TUNER
• FM Local/Distant Switch
assures proper input load for
either strong or weak signals.
-$216.00 including cabinet
Inter-Channel Balance is an exciting new concept in stereo tuning! It gives you the requisites
for good stereo: optimum balance of sensitivity and reception between the AM and PM channels. The result is balanced stereo at its best . .. yours to enjoy with minimum manual balancing
and adjusting.
The new ALTEC 309A AM/ PM Stereo Tuner is a product of this latest ALTEC development.
Because of Inter-Channel Balance, it offers important operating and performance advantages
for stereo that conventional "two-in-one" combination tuners can't match. In the 309A, output
sensitivity through both channels is equalized for balanced reception of either local or distant
stations. The basic quality of AM performance is improved to match quite closely the inherent
quality of PM. Again, the result is balance- an ingredient that is essential to proper stereo
reproduction.
Truly, the new 309A AM/ PM Tuner is made for stereo-ALTEC stereo circuitry and design,
ALTEC stereo Inter-Channel Balance, and convenient control facilities that are described at
top right. The 309A is an exciting new tuner because it was developed by ALTEC specifically
for stereo operation. See and test the 309A at your ALTEC Distributor's today. A look and a
listen is all it takes!
ENJOY
BALANCED STE REO WITH'
LOOK-A-LIKE MATES FROM ALTEC
The popular ALTEC 353A Stereo Amplifier-Preamplifier is a desirable mate to the new 309A
Tuner. Together, the pair represents a harmony of design and engineering; a perfect balance of
components for a superb all-ALTEC Stereo System.
.
The ALTEC 353A provides 14 stereo or mono inputs , 6 outputs ; matricing network for
3-channel stereo; 100 watts stereo program peak power; 50 watts rms continuous, stereo or
mono; less than 1% THD at 25 watts 1000 cps, each channel and less than 1% THD at 20
watts 30 to 15,000 cps, each channel; and frequency response ± 1.0 db 20 to 20,000 cps at
25 watts, ± 0.5 db 10 to 30,000 cps at 1 watt.
I:.'I!ii33n
ALTEC 309A AMi FM STE REO TUN ER
ALTEC 353A STER EO AM PLI FI ER· PR EAM PLI FI ER
- $2 16 .00 I NC L UD I NG CA BI N ET
- $22 5.00 I NCLUDIN G CA BINET
., , , ..
•" •
" "
SPECIFICATIONS:
FM
Antenna: Standard 300 ohmMaximum Sensitivity: 2 microvolts
-Quieting Sensitivity: 2.9 micro·
volts for 20 db/7.0 microvolts for
30 db-Frequency Range: 86.5
to 108 mc-Image Rejection: 45
db-IF Rejection: 55 dbDetector Peak Separation: 450 kc
-Frequency Response: ± 1 db
20 to 20,000 cps-Antenna
Radiation: Meets FCC require·
ments.
AM
Antenna: Built·in Ferrite Antenna,
plus external antenna connection
-Maximum Sensitivity: 3.2
microvolts-Loop Sensitivity: 35
microvolts per meter-Frequency
Range: 540 to 1630 kc-Image
Rejection: 65 db-IF Rejection:
50 db-Selectivity: 6 db bandwidth: "Local" 13 kc, "Distant"
6 kc - Whistle Filter: 10 kc atten·
uation better than 40 db.
GENERAL
Power Supply: 117v 60 cps 45
watts-Dimensions: 5'l's" H x
15" W x 10%" D (over knobs
and antenna)-Weight: 15 Ibs.
©
1961 Altee Lansing Corporation
For free informative stereo catalog. visit your Altec Distributor or write Dept. A-2
ALTEC LAN SING CORPORATION
A Subsidiary of Ling - Temco Electronics; Inc.
1515 South Manchester Avenue. Anaheim. California • 161 S i xth Avenue. New York 13, New York
AUDIO
•
FEBRUARY, 1961
39
Fig. 5. The effect
of the diaphragm
arrangement of
Fig. 4: the solid
cu rve shows the
fluctuation caused
by the transiti o n
when successive
rings become ina ctive; the dotted
line sho ws what
might be expected
if the transition
were continuous.
MAIN DIAPHRAGM
+10
-"
"0
0
I
":::""
50
...~-IO r
~
-20
2
the voice coil will offer fairly high mechanical resistance to being moved by
the diaphragm, and hence the electrical
effect can be considered as equivalent to
a mechanical high impedance source.
The effect of viscosity in the spidel' will
merely add to the effective mechanical
source resistance.
Nonlinear Distortion
A more important feature of the
spider is that its compliance should have
lineal' properties. The restoring force
should always be proportional to the
, deflection, otherwise it will distort the
movement of the diaphragm.
There are two possible causes of nonlinear distortion in a loudspeaker:
(1) due to nonlinearity of the driving
force, because the magnetic flux in the
air gap is nonuniform. This will mean
that the same current in the voice coil will
not produce the same force at all positions
in the gap, and consequently the driving
force from the voice coil will not be uniform with the electrical currents supplied
to it.
100
What is the effect of a small diaphragm attached to the same voice coil
inside the larger one, as at Fig. 3 , .
From the mechanical standpoint this additional diaphragm is not likely to produce any irregularities. It will vibrate
as an entity at the upper frequencies,
and so will not behave as a transmission
line, like the large one. For this reason
it will prove more effective for the radiation of the higher frequencies in the
band. As regards its effect on uniforDlity of movement at different frequencies, it should have quite a lineal' performance because it exerts a uniform
additional opposition force at the voice
coil. Its principal effect will be that of
increased effective mass at the voice coil.
If it were attached at some point between the center and periphery of thc
large diaphragm there would be a time
delay which would cause reflection defects and irregularities in the frequency
response of the movement against driving force. But being attached directly to
the voice coil former it should not produce this kind of effect. However, it
may produce irregularities due to acoustic effects in the air adjacent to the two
diaphragms. This must be considered
separately.
c4
cl
ml +m2
rl
1
B.
V OICE
CO IL
A,
Fig. ~. Another method of improving the performance of a large diaphragm: (a) a
phYSical cross-section throu gh the voice coil and diaphragm assembly; (bl electrical
equivalent circuit.
40
1"
".
(,
V
Special Diaphragms
Fig. 3. One kind of modification to a
loudspeaker diaphragm that is designed
to augment the reproduction of higher
frequencies.
1-'
1/
(2) due to nonlinearity of the opposition to movement, because the restoring
force is not linearly proportional to the
deflection of the diahragm. This means
that the movement of the diaphragm will
not be uniform with the force applied
to it.
EXTRA DIArI"K A'bM-'
FOR " HIGHS "
-- I--'
5
10000
1000
20000
FREQUENCY IN CYCLES PER SECOND
There is another way of dealing with
this problem which consists of introducing corrugations into the cone at one
or more poqts other than the periphery.
This is then analogous to a lump-loaded
transmission line, in which the inductance and capacitance comes in lumps instead of being continuously distributed.
This is illustrated at F ig. 4.
There is a difference between this arrangement and a transmission line: in
this arrangement, energy can be radiated by movement, represented by current, in any part of the diaphragm j this
is shown by resistance elements j III a
--I
COMPLIANCE
OF DIAPHR AGM
MOUNTING
MAS S OF
A IR LOAD
RA DI ATI ON
RE SISTANCE
Fig. 6. Electrical equivalent circuit for the
low frequency resonance of a dynamic
type loudspeaker, not taking into account
any effects due to an enclosure.
transmission line, we usually consider
only the energy reaching the far end,
which in this case is wasted in the surround.
At the lower frequencies, energy is radiated from the whole diaphragm; at
higher frequencies, the low-pass action
of the line elements prevents transmission to the outer rings and all the energy
is radiated from the inner section (s) .
The effect of this system is to produce
a very gradual fluctuation in efficiency,
represented in the response at Fig. 5.
Compared with Fig. 2, this is an improvement, but the uniform diaphragm
correctly damped can be better.
To summarize then, the mechanical
part of the loudspeaker has two principal properties that contribute to its
frequency response. These are:
(1) A major resonance, due to the mass
of the whole of the diaphragm and voice
coil, together with a quantity of air that
can be considered as moving with it, in
conjunction with the compliance of the
surround and spider (neglecting for the
moment the compliance of the air in contact with the diaphragm).
AUDIO
•
FEBRUARY, 1961
"""it's the newC&UOc0C&OO
TR-30 TRI-ETTE*
3-WAY LOUDSPEAKER SYSTEM
.
I
We believe you will agree that the new Jensen
TR-30 TRI-ETTE is the finest small speaker
system produced regardless of cost. Superior
quality precisely engineered components, brilliantly
matched and balanced, provide the ultimate in
home speaker performance. And you have the choice
of styling that includes smart Danish in warm
Walnut, subtle Contemporary in clean Limed Oak,
the elegance of Traditional Mahogany, authentic
Provincial in lustrous Cherry or a special unfinished
utility model to paint or stain as you choose ...
excellent for custom building-in, too. Furniture
( models are finished on all four sides providing the
I' \~
versatility of horizontal or vertical placement .
!II .I;f..; The accessory matching base creates a small-scaled
~_-:. consolette if you prefer. See and hear the TR-30
TRI-ETTE soon ... it's wonderful for mono
hi-fi ... supe"rb as a stereo pair.
.
TR-30 TRI-ETTE furniture models-$159.50 (without base)
Unfinished model $134.50 Consolette base $9.95
CHOOSE
FROM FIVE
"DECORATOR
GROUP II
FURNITURE
STYLES
TR-30 TRI-ETTE FEATURES NEW COMPONENTS
o
r-.
Featuring a new advanced-design 12" FlEXAI R* woofer with
n C&DU<0C&DU
MANUFACTURING COMPANY
C7'
W O IVIS I ON OF THE MU TER
6601 S. Laramie Ave., Chicago 38, Illinois
In Canada: Renfrew Electric Co., Ltd., Toronto
In Mexico: Universal De Mexico, S.A .. Mexico, D.F.
@)
..,::::::
7
.,."M ",,,,"," m,.""'" ,,. """,,," '"" '"",," ~G
· · '0."
~
0 .. 0 .:e:;.
A
0
I
___ precisely coordinated with the BASS-SUPERFlEX*
enclosure to carry bass down lower and better than ever
before. Advanc ed deSign Improved compressiOn midrange
and supertweeter units for smooth, balanced, extended
response_ Be su re to see and hear the TR-30 _ •. you'll
make a wonderful discovery!
.
,
.
Write for free illustrated Brochure" KU"
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AUDIO
•
FEBRUARY, 1961
f
41
REFLECTED IMPEDANCE
Fig. 7. The electrical impedance diagram,
showing the components reflected into
the electrical circuit due to the mechanical resonance represented in Fig. 6.
These two major lumped components
produce a low frequency resonance, the
equivalent circuit of which is shown at
Fig. 6.
(2) At the high frequency end of the
response the diaphragm tends to behave as
a transmission line, causing some degree
of breakup. The continuous type of transmission line cannot readily be shown as an
equivalent circuit, because it consists of
an infinitely distributed mass and compliance, the configuration of which is similar
to that of a low-pass filter as at Fig. 4
but when the number of inductances and
capacitances is infinitely large, and each
is infinitely small, the arrangement does
not produce a low-pass characteristic, but
a progressive phase delay which can become several cycles by the time the terminating point, which is the periphery of
the diaphragm, is reached.
Irregularities at this end of the response
can be minimized either by ensuring that
the equivalent continuous transmission
line is correctly terminated, by attention
to the properties of the surround material
or by the alternative lumped arrangement
of Fig. 4.
Electromechanic-al Coupling
The analogy circuit of Fig. 6 shows
the resonant circuit as a series one because this is the way the mechanical behavior of the circuit works out, but the
electrical characteristics as measured at
the voice'-coil terminals will also be influenced by the resonance. Because the
diaphragm movement is greater at this
resonant frequency there will be an increased back e.m.f. in the voice coil which
t ; ) M A SAIR
SO
SOUND
IN F
PRESSURE
NECK
OUTSIDE
NEC K
COMPlI-
t~
ANCEOF
AIR INSI DE
B.
Fig. 8 . A narrow necked bottle, or Helmholtz resonator, ill ustrates the basic
acoustical analogy: (a) a cross-section
through the bottle; (b) electrical equivalent circuit for same.
42
will represent an increased dynamic impedance. From this it will be found that
the electrical equivalent must take the
form shown in Fig. 7.
This shows that the mechanical analogy series circuit transfers through the
electromechanical action to become an
effective parallel resonant circuit. The
magnitude of the reactance values in this
electrical resonant circuit will depend
on the efficiency of the electromechanical transfer.
Similarly, looking at the mechanical
arrangement the effectiveness of the
electrical damping, provided by the
voice coil with a high damping factor
amplifier, will also depend upon the electromechanical efficiency. This means the
effectiveness of any attempt at damping
by adjusting the amplifier damping factor is definitely limited.
Mechanical-Acoustical Coupling
We have discussed the factors controlling the relationship between the elec-
A.
MASS OF AIR
IN NECK I
MASS OF AIR
IN NECK 2
SOUN~SOUND
PRESSURE
OUTSIDE
NECK 1
I
..l..COMPlI ANCE
OF AIR
_
INSIDE
PRESSURE
OUTSIDE
NECK 2
B.
Fig . 9. Bottle with two necks: (a) physical
cross-section; (b) equivalent circuit.
trical driving force and the diaphragm
vibration. The next thing is to transfer
the diaphragm vibration to the ail'.
To see how these things work we need
to understand the acoustical analogy.
Here we make the sound pressure in a
wave correspond to voltage. The volume movement velocity of air corresponds to current. The volume displacement will correspond to charge.
Acoustical resistance due to the viscosity of the air when particles have to
move over some surface or one another,
is equivalent to resistance. The mass, or
inertia, of the air in movem'e nt is equivalent to inductance; while the compliance, or compressibility of the air, is
equivalent to capacitance.
These last two are the most important
ones to understand and particularly is it
important to grasp how they fit together
in an equivalent circuit. Consider a
Helmholtz resonator-or just a bottle
with a narrow neck-as at Fig. S.
The air inside the bottle contributes
to the resonant frequency excited at the
Fig. 10. Cross-section of simple acoustical
transformer, applied to a horn type loudspeaker unit.
mouth merely because of its compressibility. This air does not move appreciably-it just compresses and expands
alternately. In the neck of the bottle,
on the other hand, the air oscillates to
and fro, and hence the important feature
about this "piece" of air is its mass. So
the resonant frequency is determined by
considering the effective compliance of
the volume of air inside the bottle, in
conjunction with the effective mass of
the air that goes to and fro in the neck.
As a very small sound pressure at
resonant frequency will cause a big volume movement of air in the neck of the
bottle, the equivalent circuit is that
shown at Fig. Sb, it is a series resonant
circuit.
Now suppose we have a container with
an opening at both ends and a volume
of air enclosed as at Fig. 9. A sound
pressure at one opening will have immediately next to it the opposing force
of the mass of ail' in the neck which
looks like an inductance. At the other
end of this neck is the volume of air
the compliance of which looks like a capacitance. As the pressure of all the air
in the bottle is approximately uniform
throughout, the mass of air at the other
end of the space has the same pressure
at its input side as has the mass of air
at the first neck on the inside of the
bottle. This whole volume is at constant
pressUl'e at any instant in time.
So the inside of both necks must be
MAGNET
Fig. 11. An improved type of acoustical
transformer.
AUDIO
•
FEBRUARY, 1961
.THE
ITATION
SOUND~'
"Over and above the details of design and performance,
we felt that the Citation group bore eloquent witness to
the one vital aspect of audio that for so many of us has
elevated high fidelity from a casual hobby to a lifelong
interest: the earnest attempt to reach an ideal-not I'Ot'
the sake of technical showmanship-but for the suke of
music and our demanding love of it,"
Herbert Reid, Hi Fi Stereo Review
A truly remarkable commentary about a truly remarkable
group of products-the Citation Kits by Harman-Kardon.
Mr. R;e id's eloquent tribute to Citation is one of many extraordinary reviews of these magnificent instruments. We are
proud to present a brief collection of excerpts from Citation
reviews written by outstanding audio critics.
"When we first heard the Citations our immediate reaction
was that one listened through the amplifier system clear back
to the original performance, and that the finer nuances of tone
The CITATION I,
Stereophonic Preamplifier Control Center
The many professional features and philosophy
of design expressed in Citation I perm it the
development of a preamplifier that provides
absolute control over any program material with·
out imparting any coloration of its own . The
Citation 1- $159 .95. Factory Wired - $249.95.
The CITATION IV,
Stereophonic Preamplifier Control Center
A compact stereophonic preamplifier designed
in the best Citation tradition. It offers perform·
ance and features rivaled only by Citation I. The
control over program material provided by the
new Citation IV enables the user to perfectly
recreate every characteristic of the original per·'
formance. The Citation IV - $119.95 - Factory
Wired-$189.95.
AUDIO
•
FEBRUARY, 1961
"... FOR THE SAKE OF MUSIC AND
OUR DEMANDING LOVE OF 11."
shading stood out clearly and distinctly for the first time ...
The kit is a joy to construct."
C. G. McProud, Editor, Audio Magazine
"The unit which we checked after having built the kit, is the
best of all power amplifiers that we have tested over the past
years."
William Stocklin, Editor, Electronics World
"Its listening quality is superb, and not easily described in
terms of laboratory measurements. Listening is the ultimate
tes t and a required one for full ~ppreciation of Citation ....
Anyone who will settle for nothing less than the finest will be
well advised to look into the Citation II."
Hirsch-Houck Labs, High Fidelity Magazine
"At this writing, the most impressive of amplifier kits is
without doubt the new Citation line of Harman-Kardon ...
their deSign, circuitry, acoustic results and even the manner of
their packaging set a new high in amplifier construction ·and
performance, kit or no."
Norman Eisenberg, Saturday Review
The CITATION II,
120 Watt Stereophonic Power Amplifier
Will reproduce frequencies as low as 5 cycles
virtually without phase shift, and frequencies as "
high as 100,000 cycles without any evidence of .
instability or ringing. Because of its reliability
and specifications the Citation II has been ac·
cepted by professionals as a laboratory standard.
The Citation 1I-$159.95-Factory Wired $229.95.
The CITATION V,
80 Watt Stereophonic Power Amplifier
A compact version of the powerful Citation II.
DeSigned with the same lav ish hand, it is can·
servatively rated at 40 watts RMS per channel
with 95 watt peaks at less than 0.5 % distortion.
The availability of rat ed power at the extreme
ends of the frequency ran ge enables the unit to
effortlessly drive the most inefficient speakers.
The Citation V-$119.95. Factory Wired-$179.95.
The CITATION III,
Professional FM Tuner
The world's most sensitive tuner. But more
important-it offers sound quality never before
achieved in an FM tuner. Now, for the first time
Harman·Kardon has made it possible for the kit
builder to construct a completely professional
tuner without reliance upon external equipment.
The Citation Ill's front end employs the revo·
lutionary Nuvistor tube which furnishes the low·
est noise figure and highest sensitivity permitted
by the state of the art. A two·stage audio sec·
tion patterned after Citation II provides <I fre·
quency response three octaves above and below
the range of normal hearing. The Citation III is
styled in charcoal brown and gold to match all
the other Citation instruments. The Citation III
-$149.95-Factory Wired-$229.95.
for complete information on the new Citation
Kits, including reprints of independent labora·
tory test reports, write to: Dept. A·2, Citation
Kit Division, Harman·Kardon, Inc., Plainview,
New York.
All prices slightly higher in the West.
.CITATION ,KITS
.;&U"S,,'
by
kardon
I
+10
...
I
-"
0
.!.
§
'-
.,.~
,F
::>
0
~
;::- 10
~
'"
-20
(
\
"'1
/
V
20
100
10000 20000
1000
FREQUENCY IN CYCLES PER SECOND
represented, in an equivalent or analogy
circuit, by the same electrical point in
the network. This means that the analogy circuit of the whole arrangement
looks like a low-pass "T" filter configuration as at B in Fig. 9.
From the acoustic response viewpoint
it would not matter appreciably whether
the two necks were located at opposite
ends of the space, or next to one another, or in any other position, because
the pressure inside will vary without appreciable volume movement of the air.
In practice there will be some slight difference due to the fact that air does
move to a small extent inside the space.
There is not a sudden transition from air
that moves to air that compresses. There
is a small region where the air does both.
former changes the ratio of voltage and
current from one impedance to another.
When sound is radiated outward
freely, the air near the source moves
more, for the pressure fluctuation involved, than the air further out. This
means it has an inductive component
to its impedance. In fact a large proportion of the inductance in Fig. 6 is
due to radiation. This is why the resonance of this kind of speaker has to be
at the low-frequency end. That way, a
constant voltage, representing constant
sound pressure, is delivere.d to the inductance-resistance combination. This
principle is termed mass-controlling diaphragm movement, because the principal
reactance opposing movement is mass,
throughout the audio spectrum.
Propagation
Application
A sound wave propagated through air
in the form of a plane wave-that is,
where the frontal area of the wave is
not expanding-presents a transmission
impedance that is characteristic, because
the pressure and velocity get passed on
unchanged, except for a slight attenuation due to the viscosity of the air.
A continuous exponential horn above
its cut-off frequency looks like a resistance too. This is because the wave propagates down the expansion and produces
a gradual transition, from high-pressure
high-volume movement at the throat or
neck, to a low-pressure low-volume
movement at the flare end. If the rate of
transition from one end to the other is
correct, the ratio between the pressure
and particle velocity at all points down
the development will be uniform, which
means that the horn development looks
like a constant resistance.
A transition in area, from small to
large, or large to small, through a relatively short distance, behaves as an
acoustical transformer. In a narrow neck,
for instance, a high pressure with a
given volume displacement, on reaching
a sudden expansion encounters a sudden
freedom of movement which causes the
pressure to drop. At the same time the
volume movement is allowed to increase
at this point. So the step in area exchanges one ratio of pressure to volume
movement for another ratio, like a trans-
All of these simple acoustic devices
occur in loudspeaker design somewhere
or other. The acoustic transformer is
utilized in horn-type loudspeakers to
match the diaphragm movement to the
throat of the horn. Usually the diaphragm is larger than the throat of the
horn as shown at Fig. 10. The air movement picked up from the diaphragm has
to be compressed down to the size of the
throat.
If any cavity is enclosed between the
diaphragm and the throat, this will behave as a capacitance and cause a highfrequency roll-off by absorption. So, to
minimize the volume of such cavity a
44
good method adopted is the use of a
number of channels to pick off the pressure uniformly from different parts of
the diaphragm 'and conduct the column
of ail' into a single throat, as shown in
Fig. 11. This makes an efficient transformer up to quite high frequencies,
whereas the abrupt change in size loses
efficiency at the high frequencies due to
the capacitance effect of the cavity which
it produces.
Another example of cavity effect can
occur with the diaphragm arrangement
shown in Fig. 3. As it is not a deep cavity-nor does it have a narrow mouthits effect will not be very pronounced,
but it will result in a slight absorption
over a fairly wide range of frequencies,
as suggested in Fig. 12.
Fig . 12. The acoustica I effect of the
diaphragm shown
in Fig. 3: the sol id
curve sh o ws t h e
response
prod uced, the d otted
o ne the the o retical effect of elimin a ti ng the aco ustic a bso rpti o n. The
sectio n
d o t-dash
represents removing the small diaphragm.
Enclosures
But the thing which is of greater interest in loudspeaker design is the construction used for the lower frequencies
-enclosures of various types. The bassreflex enclosure operates in a manner
similar to the container with a neck at
both ends, the diaphragm being placed
in one neck as the driving point, while
the other neck is the vent of the enclosure.
F igwre 13 shows the simplified analogy
diagram f or a bass-reflex enclosure, assuming that the volume is pure capacitance and the port pure inductance. In
practice these assumptions are not quite
true, but they do not seriously invalidate
the representation. This circuit shows
how the enclosure can damp the basic
resonance of the speaker by having the
combined dynamic impedance consisting
of the port, the volume of the enclosure,
and the radiation resistance, as a shunt
tuned circuit, damp the series tuned circuit, consisting of front radiation resistance with the effective mass and
compliance of the diaphragm and its
associated components. It is possible for
these two to be exactly complementary so
as to damp out the mechanical resonance
of the diaphragm system.
If this was all that a bass-reflex enclosure did it would merely pull down
RADIA TI ON
M2
R2
Cl
C2
Rl
Ml
--IH~MNIr-f'/flll!lflf\
M2
VO ICE
CO IL
FORCE
R2
B.
A.
Fig. 13. The action of a bass reflex enclosu re is somewhat simi lar to the bottle with
tw o necks of Fig. 9: at (a) a cross-secti o n th rough a ba ss refl ex e ncl osure; (b) the
equivalent circuit.
AUDIO
•
FEBRUARY, 1961
AN AM:PEX
FOR EVERY PROFESSJ:ONAL NEED
In sound qu.ality, , , in features, , , in lasting economy. , , these four Ampex professional recorders maintain the highest performance standards for broadcasters, recording studios,
educators and other critical users, For 7" reel requirements-the PR-10 series-newest in
studio quality compact recorders, priced from $845, For 10'1/ reels-the 351/354 series
-proven by more than 10,000 units in use throughout the world Other
10~"
Recorders
include the 300 series multi-channel Mastering series with up to 8 tracks, Your Ampex
dealer will aid you in selecting the Ampex which best fits your needs, And ask him about
the new Ampex Finance and Lease Plans,
7/1 REELS
THE PR-10-l
MONOPHONIC,
THE PR-10-2.
STEREO/MONO
Two-channel electronics fit some
rock space as PR-10-1. Po rtable
for remote pickups as well a s inst udio use . Spli t erose permits
ste reo recording , half-t rack mono
Full or half-track . Single-channel
electronics in~lude built-i n mi xe r
to mix line and mike or two mikes
Iwith plug-in pre-a mp}. Portable,
or fit s 14" of rock space . 3'/, and
7'/,; or 7 '/, and 15 ips speeds.
Exclusi ve se lf -thread ing option.
Ali gnment con trols in front panel .
New frict ionless top e handling .
AII-el eel ri c push.button controls
recording, cue track , and soundon-sound. Two line inputs can·
ve rtible Iw ith pre-amps} to two
mikes - one pe r channel. Addi tional mike and line inputs possible with MX-10 mixe r. Write for
Bulletin 212 .
permit re mote control operation.
Wri te for Bull eti n 212 .
10Y2/1 REELS
THE AMPEX 351
MONOPHONIC
THE AMPEX 354.
STEREO/MONO
Available in full or holf·track
models . Input switchable to mike,
balanced or un balan ced line .
To kes reels from 3" to 10'/,".
Speeds: 3'/, and 7,/, or 7 '/, and
15 ips. Available as console, two·case portable or mounts in 22%"
of ro ck space. AII·electri c pushbutton control s permit remote
con trol operation . Lorge 4" VU.
meter reads input or r eco rded
level plus bios and erose current.
Two ·c hann e l e lectronics .. Co mpael and portable version as well
For more infor mation , wri te for
track mono , cue tro ck , sound-on -
Bulletin 203 .
sou nd . Alignment controls in
front panel. Bulletin 208.
a s console. ,Requires c;ml y some
ro ck space as 351. Some hea vy
duty tope transport as 351.. Two
line inp uts, convertible to two
mikes lone per channel} with preamps. Mo re mike and line inputs
w ith MX·35 mi xer . Convenient
balan cing of stereo-channels with
side -b y· sid e VU me ters. Split
e ro se for ste reo reco rding , half-
ACCESSORIES AND ASSOCIATED EQUIPMENT
iAMPEXI
I
MONITOR SYSTEM
SA-lO, Con sole quality, 40
STEREO/MONO MIXER PLUG-IN EQUALIZERS
MX-10 or MX-35, Four posi - provid e NAB AME o r CCIR
PLUG-IN INPUTS
match va ri o us inputs . Bal-
watt speaker-amplifier unit ..
tion, two channels, matches
anced brid gi ng or mikes.
Portable, rock or wall
mounting . Bulletin 214 .
PR-10 or 351/354 .
curves as requ ired .
Complete descriptive literature also available on 300 series Mastering Recorder and High Speed Duplicators from Ampex. Write Dept. A
AMPEX PROFESSIONAL PRODUCTS COMPANY. 934 Charter Street, Redwood City, Calif. • Ampex of Canada Ltd. , Rexdale, Ontario
AUDIO
•
FEBRUARY, 1961
.45
+10
i-- A
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12
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80 '100
200
300
60
FREQUENCY IN CYCLES PER SECOND
the peak at the low-frequency end of
the loudspeaker's response curve without extending the frequency range any
lower down, as in Fig. 14. But the additional mass (inductance) of the port,
lowers the resonant frequency, without
having to make the diaphragm mass too
great for good operation at higher frequencies.
At the mutual resonance of the system
the radiation from both the diaphragm
and the port is in phase. This can be
appreciated best by thinking of the resonance of the bottle with two necks. Although the energy is excited in one neck,
due to the fact that the air inside the
bottle compresses and expands as an entity, the air flow in the two necks will
be almost exactly in phase, there being
just a slight lead in the one providing
the drive. This is in fact what happens
with a vented enclosure.
In the case of the latest type of lowfrequency reproducer the mechanical
construction is made with a very large
compliance, so that the natural resonance
is extremely low (this is when no enclosure is used). Then the size of the enclosure, which is sealed and not vented,
is adjusted so that the over-all compliance of the diaphragm and that of the
enclosure produces a resonant frequency
at the extreme bottom end of the audio
spectrum- where it should be. The interior of the cabinet is treated to provide an acoustic resistance effect that
CI
-I
. . . . t--
Fig. 14. Action of
a bass-reflex enclosure. A is the
curve of the unit
without an enclosure; B represents
the effect of the
enclosure in pulling down the
peak.
damps the resonance. An analogy circuit
is shown in F i g. 15. In this wayan extremely smooth low-frequency response
can be obtained.
This is just one approach to the problem and it involves the use of one of the
newer special type loudspeaker units,
with extremely high compliance, so that
the diaphragm appears to be very floppy.
These units can only be used in such
enclosures, otherwise they would rapidly
damage themselv'es.
Other approaches to the low-frequency
problem use all kinds of enclosures with
labyrinths and folded horns. In the case
of a folded horn, the objective is to
maintain a correct exponential rate of
expansion during the folding of the expanding channel in different directions.
This w'a y effective transmission is
achieved without the need for the excessive length necessary in a straight horn
development.
Some units use a folded horn development from one side of the diaphragm,
usually the rear, with a built-in acoustic
low-pass filter, using a large cavity for
the capacitance and a slot for the beginning part of the horn as an inductance. This makes the horn useful for
only a comparatively narrow range of
frequencies between its own natural cutoff, which is very low, and the acoustic
low-pass filter cutoff. The entire arrangement provides loading for the rear
of the diaphragm in this frequency
M2
Ml
B.
Fig. 15. A comparatively new method of handli ng low-frequency response: at (A) a
cross-section; at (B) an analogy diagram, Cl is several times as great as C2 , so that
the laffe r becomes the controlling compliance.
'46
range. Above the low-pass cutoff frequency the diaphragm loses its rear loading, allowing it to radiate from the front
side. So the result is, that frequencies
above the chosen crossover, which may
be, say, 200 cps, are radiated directly
from the front of the diaphragm, while
frequencies from 20 to 200 cps are r adiated via the acoustic horn, This is illustrated at F i g. 16. In this case, the length
of the horn and the position of its mouth
must be adjusted so that the radiation is
in phase from back and front of the dia-
M2
Cl
t'\1
Rl
r
~~r
FRONTOFl
DIAPHRAGM
B,
Fig. 16. Another kind of low-frequency
system, using a folded horn and acoustic
low-pass filter: (A) a simplified physical
diagram (in practice the horn is folded,
to save space); (B) analogy diagram. The
val ue of r2 is much greater than rl' so
that for frequencies below the acoustic
low-pass filter (c 2 , ma) rolloff the major
radiation is from the horn. Above this
freq uency r2 ceases to be coupled, so the
major radiati on is from r l , m 2 • The physical disposition of the horn mouth and
diaphragm must be such that, at the
chosen crossover, the energy from both
emerges in phase.
phragm at the chosen crossover frequency. This is just an example.
To give details of every enclosure system on the market would take a separate
article to describe each and show how its
design was developed. The foregoing
provides a basis so that anyone inter ested can figure out how any particular
loudspeaker system has been engineered
to get the desired results. This knowledge
will then prove helpful in judging to
what extent the design is successful in
achieving its objective.
.IE
AUDIO
•
FEBRUARY, '1961
UNDISTORTED SOUND ••• ABUNDANT POWER
PIONEER MODEL SM-B180 AM-AM/FM STEREOPHONIC AMPLIFIER
Now available is a new PIONEER stereophonic amplifier,
the model SM-BISO_
Providing exceptional tonal "q uality, the two channels of this
stereophonic amplifier each employ a pair of 6BMS (ECL-S2)
type tubes.
Each channel has a rated power output of 10 watts, ample
power for home applications.
Since the SM-BISO is designed for use in conjunction with
crystal or ceramic type pickup cartridges, simple handling
is another of its many outstanding features, yet despite this,
its performance will satisfy the most critical ears.
Whether it be reception of stereophonic broadcasts or
playback of records, the SM-BISO is the amplifier for you,
the amplifier that provides superb stereophonic reproduction for your listening pleasure.
A TRANSISTOR PREAMPLIFIER,
THE PIONEER STP-l,
that facilitates use of low-output
magnetic cartridges in conjunction with amplifiers designed for
crystal or ceramic cartridges ...
* Can be used if the output of your cartridge
*
*
*
is anywhere between 2.5 to 35 millivolts;
Is equipped with two independent channels,
and so it may be used for both monophonic
and stereophonic applications;
Has exceptionally low distortion and virtually
no noise;
Operates from standard 9-volt laminated
FUKUIN ELECTRIC, LIMITED
5 Otov-.:acho 6-chome, Bunkyoku,
Tokyo, Japan
AUDIO
•
FEBRUARY, 1961
*
*
*
dry batteries used in transistor radios
available anywhere;
Extremely low current drain-battery will
last as long as six months in normal
oPeration;
Extremely simple connections;
Recommended for use in conjunction with
PIONEER's SM-BISO or SM-Q140 amplifiers.
pioneer
47
Ea UI PJ'J\ Ef'l ~r
Ilttt:ttt'ttttd
u
p
"'"
PROfilE
SARCENT-RAYMENT SR-8000
STEREO TUNER-PREAMP AND
SR-202 REVERBERATION UNIT
The basic difference between high-quality
preamplifiers resides in the fundamental
system philosophy underlying the design,
for any engineer worthy of the name
should be able to design an amplifier which
is equivalent to any other amplifier, as far
as performance is concerned. Almost the
same statement applies to tuners, either
AM or FM, and the basic difference between the performance of two different
tuners can be determined almost by the
pl'ice, tag alone. It is very unlikely that
some one manufactUl'er has found the
secret of making a piece of high-quality
equipment at a cost differential of much
more than 10 per cent below another.
Sargent-Rayment equipment has never
been low priced. Neither have Cadillacsat least within the memory of most of
you. (There was a time when Fords cost
$900 and Cadillacs cost $SOO, but that was
around 1909.) But if it has not been low
priced, it has at least been of high quality.
We have reported in these pages the SR-6S,
an AM/FM tuner; the SR-5S, AM only;
and the more recent SR-1000, an AM-FMstereo tuner of superb listening quality.
Barring the now defunct t.r.f. tuners generally following the design of the old
Western Electric 10-A Radio Receiver, it
is probable that the SR-1000 had better
AM quality than most anything else on the
market. The SR-5S was better, but with the
great increase in FM listening, AM receivers have become almost as obsolete as
24A tubes.
~
The SR-SOOO combines an FM tuner, an
AM tuner, and a complete stereo preamplifier in one chassis. The AM tuner section is
practically the same as the AM section in
the SR-1000, and consists of a 6BE6 mixeroscillator and a 6BA6 i.f. amplifier stage
feeding the patented Sargent-Rayment AM
detector, which has a very low distortion.
The SOOO employs two germanium diodes
as the second dete~tor, resulting in a saving of space as compared with the SR-1000.
Both models used i.f. transformers with
tapped secondaries connected to switches
to provide narrow or broad-band reception,
with a resultant improvement in the highfreqnency r esponse when in BROAD.
The FM sections differ considerably in
detail, though not in philosophy. The SRSOOO employs the inductance-tuned dual
triode circuit originally developed in Europe and furnished as' a separate and completely self-contained cartridge. A.f.c. is
provided by the use of a voltage-sensitive
diode in series with a small capacitor and
controlled from the r atio detector circuit.
Two i.f. stages and a single limiter serve
to feed the detector stage which employs
two diodes in a wide-range ratio detector
circuit.
The outputs of the two tuners are fed
to the selector switch of the control unit,
as are the ouputs of the two equalized preamp stages which acco=odate magnetic
pickups and t ape heads. These stages use
12AX7's with low-noise resistors in the
plate circuits of the first stages. Following
the selector switch are the SEPARATION control, the REVERSE switch, and the BALA:!:,CE
control. These are followed, in turn, by the
tone controls which feed the pentode sec-
r
I
Fig. 1. Sargent-Rayment Model SR-8000 AM/FM stereo tuner 'a nd preamplifier.
48
tions of 7199's, and these are followed by
the RECORD outputs, the SCRATCH and
RUMBLE filters, the VOLUME control with its
associated LOUDNESS switch, and the triode
sections of the 7199's. A cathodyne phase
splitter follows to provide connection to
either plate or cathode in the "A" channel
for phase reversal, and a cathode follower
only for the "B" channel.
Referring to Fig. 1, the controls are as
follows, from left to right: SEPARATION
and BALANCE, the REVERSE switch, the
SELECTOR s\vitch, with the indicator lights
showing which circuit is in operation. The
!:text five switches are PHAS:t:, FM A.F.C.,
AM BROAD, RUMBLE, and S CRATCH. These
are foll'owed by the VOLUME control, the
LOUDNESS switch, and the BASS and TREBLE
tone controls. All of the switches are of
the push type, with one push actuating the
related circuit and the next releasing it.
The AM tuning control is' at the upper left
and the FM control is at the upper right.
Using the built-in ferrite loopstick on
AM, the sensitivity is rated at 20 ~v; for
20 db quieting, the sensitivity on FM is
loS I!kV, Harmonic distortion measured at
less than 0.1 per cent on either AM or FM
at 1 volt output, with 1M distortion O.lS
per cent on FM and 0.22 per cent on AM
at the same output.
Bass controls provide a boost of 14 db
at 50 cps and a cut of 16 db at the same
frequency. The turnover point of the controls is at 350 cps. The treble controls gave
a boost and cut of 10 and 14 db respectively at 10,000 cps, with a turnover at lS00
cps. Phono equalization measured within
1 db of the RIAA standard, and the tape
head input measured within 1 db of the
NAB characteristic from 30 to 7000 cpsabove which frequency it increased appreciably over the standard, presumably to
give the needed boost for recorders with
insufficiently narrow head gaps. For a
I-volt output, a signal of 0.S7 mv was required at 1000 cps on the phono inputs,
and 1.6 mv at the tape head input. For
auxiliary inputs the equivalent input signal was measured at .057 volts. When
powered by SR amplifiers, the signal-tonoise ratio measured 72 db on phono and
tape-head inputs and 61 db on the highlevel inputs. Tracking of the volume control was measured at ± 3 db over the range
from ma..dmum to 40 db down; of tone
controls ± 5 db over the same range. As
noted, the SR-SOOO is not self powered, but
must have plate and heater supply from
some other source. All SR basic amplifi ers
are equipped with power output sockets
which will supply the required power' for
installations where a separate power s~pply
must be provided, the SR-900 furnishes the
required voltages. For the hypercritical,
the SR-9000 furnishes d.c. for both plates
and filaments.
The SR-SOOO measures 14% in. wide by
5ljl, in. high by 13% deep, and it weighs
21 pounds.
By today's standards, the sensitivity of
the FM tuner is not high, nor is that of
t he AM section. But for high-quality AM
reception, it is necessary that the listener
be within 20 miles of the transmitting station, and it is rare that good FM reception
is r eliable with signal intensities of less
than about 5 '!-tv. In other words, this is an
excellent and very luxurious tuner within
the primary service ranges of either AM
or FM stations- as a matter of fact, there
is little difference in sound quality from
AM and FM provided the noise limitations
of the AM channel allow satisfactory
broad-band reception.
One of the great advantages of the SRSOOO-as well as many other SR units-is
that they are powered from the main amplifier and therefore do not have any heat
AUDIO
•
FEBRUARY, 1961
achieve optimum stability and responsiveness-the two most
sought after qualities in arm design
The Empire 98 is at once the most stable and freely
responsive transcription arm ever designed. So pre·
cisely calculated is the distribution of arm mass, and
the location of pivot points in the center of mass, that
when statically balanced in one plane, the 98 is in
balance in all planes.
the slightest impulse - effortlessly follows the spiral
course of the record groove, favoring neither one wall
nor the other, and responding smoothly to the rise
and fall of even the most badly warped record. The 98
will track a record groove at any angle of turntable
tilt- on its side, or even upside down.
Even the application of stylus force' doesn't disturb
the arm's stability. An adjustment knob - calibrated
in grams - is dialed to the stylus force desired. This
action tightens a spring coiled around, and secured to
the vertical pivot shaft of the arm . This exerts a torque
or twisting force on the shaft which, in turn, increases
the force of the stylus without shifting the arm's center
of mass, and without upsetting its dynamic balance.
You owe it to yourself to see the Empire 98 in action,
and hear how much better any cartridge sounds in an
arm that permits the cartridge to give its best per·
formance . Visit your hi ·fi dealer today, and ask him
about the Empire 98, 12" $37.50; Empire 98P, 16",
$44.50.
Yet, for all the rock·steady stability of the Empire 98,
its lateral and vertical compliance is almost incredible.
Both pivot bearings are suspended in precision ball
races, so finely balanced that the arm responds to
1075 STEWART AVE ••
EXPORT :
CANADA :
AUDIO
EMEC.
GARDEN CITY.
P LAINVIEW .
ACTIVE RADIO &:
•
TV LTD ••
N.
N.
Y.
TRULY COMPATIBLE MONO·STEREO CARTRIDGE
' Empire 108 ... first to achieve high fidelity reproduc·
t!bn from stereo and monophonic records.
Er;npire 108 with .7 mil diamond stylus
$34.50
Empire 88 with .7 mil diamond stylus
$24.50
FREE a "Do·lt·Yourself" stereo/ balance kit actively demonstrates
scientific principles of balance-ask your dealer.
Y.
TORONTO Z . ONT.
FEBRUARY, 1961
49
••
;;.
"",
Fig . 2. SR-202 reverb e ration un it incorpora tes t he Hammond d e la y uni t
and t he Sarge nt-Raym e nt e lectro n ism . '
or hum problems from the built-in power
supply. There is something to be said for
either system, but it seems that there
might easily be adequate power available
from almost any main amplifier to feed the
relatively low power requirements of a
tuner-preamp, and the elimination of the
a.c. circuitry from the preamp chassis is
definitely an advantage.
SR 202 Reverberation Unit
The reverberation units which have ap peared on the market during the last year
are all alike in the basic principle of operation, althongh there is considerable difference in the electronic circuitry which actuates the H ammond unit which is the
heart of all the systems. The SR-202, shown
in Fig. 2, employs the H ammond unit with
the small electronic package which is
pewered from either the main amplifier or
a separate power supply such as the SR900 or SR-9000.
The Hammond unit, which consists of
two coil spring assemblies, each driven at
one end by a common transducer, with th e
delayed souud being picked up at the other
end of the springs by a similar transducer.
The individual spring assemblies consist
of two sections, wound ill opposite directions so as to preclucle "u nwindin,g" over
.-
a period of time, and the delay times of
the sections differ-one being in the vicinity of 28 milliseconds and the other
around 37 ms. In the SR system, the two
outpnts from the preamp are combined to
provide A + B signal which is fed to the
driver t ransducer. The output from the
driven transducer fe eds the two channels
simultaneously. The actual circuitry consists of two 12AX7's and a 6DJ8-all
being dual triodes. The inputs are fed to
the two grids of the first 12AX7; their
outputs are combined and fed to one section of the 6DJ8, which f eeds the driving
transducer. The delayed output from the
springs is then fed to the second section
of the 6DJ8, thence to a "volume" control
with the a rm circuitry being split to the
two grids of the second 12AX7. The unreverberated signal is fed fr om the first
to t he second stages by a resistor coupling
th e two cathodes. Thus a certain , fi."{ed
value of "direct" signals from the two
channels goes straight through, while a
controllable delayed output of the sum
signal is fed simultaneously to t he two
channels.
In the SR model, there are four positions
of the control switch-OFF, in which the
output of the preamp is fed directly to the
power amplifiers and the heater current is
switched off; REVERB. in which t he signals
Fig . 3 . Shure Studio Dy ne t ic integrate d ste re o cartr idge and a rm. Arm ta kes ei ther
stereo or mono cartridg e s.
50
are mixed and fed back with a controlled
delay into both channels, as described, in
addition to the straight through feed of
undelayed signal; ECHO A and ECHO B, in
which reverber ation is applied to either
channel A or channel B, the other being
normal.
Some reverber ation units using the H ammond device have been demonstrat ed with
too little "straight-through" signal, so that
the unreverberated signal is r elatively low
in level, and as the reverberation is added
the over -all level increases by as much as
10 db. These are, in our opinion, nothing
less than abominable. However, when the
straight-through signal is sufficiently great
th at addition of the reverberation does not
appreci ably affect the over-all volume, t~e
effect is pleasing and the H ammond umt
may be said to be performing excellently
- better, in fact, than many devices costing
several times as much.
The design of the electronic package of
the SR-202 is such that i t is not probable
that the listener will get too much reverberation. We find the over-all effect pleasing with the addition of small amounts of
reverberation-so much so that we have
installed the b asic idea into our reference
system, with some modifications, of course.
For the technically inclined, the driving
signal f eel to the Hammond unit . should
be in the vicinity of 5 volts, approxlIDately
- in any case, it should be enough so that
the signal-to-noise ratio does not suffer in
the reverberation circuit. But under proper
conditions of operation, the device works
wonderfully, and with judicious control
makes an inter esting addition to any hi-fi
system.
B-26
SHURE STUDIO DYNETIC
STEREO PICKUP AND ARM
There is much to be said for the integrated arm and cartridge, for the manufacturer is then able to adjust the characteristics of the two elements to each other
-much in the same manner as when a loudspeaker and enclosnre are engineered by
the manufacturer to complement each
other . I n 1957, the first Studio Dynetic
cartridge-and-arm made its appearance,
and we reported on the combination at that
time (AUDIO, May, 1957) . Since then we
have contin ued to find the performance of
the original pickup/arm combination practically faultless.
The stereo version of the Studio Dynetic
was bound to appear, of course, and on
outward appearance there is little difference. The arms are counterbalanced in the
same manner, with the counterbalancing
weight being supp orted on a spring steel
strip which is damped to eliminate the lowfrequency resonance which is usually encountered in th e vicinity of 5-10 cps. The
arm itself does not raise np or down- the
cartridge is mounted on a pivoted a:rm
which is also counterbalanced to prOVIde
an ad justable stylus force between 1.5 and
2.5 grams. The ca.rtridge is r aised or lowerecl by pressing a plastic button on the
top of the arm, but it is almost as easy to
slide the sty Ins across the record to the desired point without raising it (though this
is n ot recommended) since no scratch is
observable on the record surface, nor can
it be heard on subsequent playings.
The stereo arm is fitted with two cont acts for the "hot" leads from the stereo
pickup , on which the outputs appear as two
contact pins. When the equivalent mono
cartridge is to be used, the two contacts
touch both sides of its single output pin,
thus p aralleling the two amplifiers with
no change in s\vi tching b eing required. The
sleeve of th e mounting carries the common
ground terminal on the stereo pickup, as
AUDIO
•
FEBRUARY, 1961
®
STEREO SPEAKER SYSTEMS *
The exciting sound of the new Scott "Reflection Coupler" Stereo Speaker System has already made its mark on the world of music
reproduction. Hi-Fi enthusiasts-even the most
skeptical-have come away from demonstrations convinced that this system is the answer
to many of the limitations of stereo as reproduced by direct radiator speaker systems.
The Scott system is based on a wholly new
design * in which the sound is reflected off the
floor and walls, eliminating any point source
of sound. The wall against which the system is
playing becomes the sound source, just as the
stage is the sound source in a live performance.
The stereo effect is fully dimensioned as to
spread and depth. and height, with no gaps in
the sound. And th e stereo effect is the same
everywhere in the room, eliminating the need
for "front and center" listening.
Have you heard the Scott "Reflection Coupler"
Stereo Speaker System? No one can describe
how a speaker system sounds. You really must
hear it for yourself. Once you have heard the
system, we have some other exciting surprises
in store for you.
Due to its unique design, the Scott Speaker
System has more versatility of application than
any other speaker system. It can be placed out
of sight under or in back of other furniture. In
the authentically designed, hardwood Scott
Custom benches and cabinets, the possibilities
are endless. Here are some of the ways you can
use the system-
Use any Scott
bench with cushions
or
without
or as a planter
or
as a combination
bench and planter
Use a cabinet
for record rr--,,,,,,,,,,,,,,,
hi-fi
or
equipment
'---f~=11
for linen, glass,
silver or china;
or as a cellarette
However you use the Scott Speaker System,
you never see it. It is truly "the invisibJe
speaker system."
Many fine audio and music stores are no:w
featuring the SCOTT "Reflection Coupler"
Speaker System. Write to Dept. B-2, SCOTT
Radio Laboratories, Inc., 241 West Street,
Annapolis, Md., for a descriptive brochure,
price list and the name of your nearest dealer.
"The sound of Scott is the sound of music"
SCOTT RADIO LABORATORIES, Inc.
241 WEST STREET, ANNAPOLIS, MARYLAND
• Patent Applied For
AUDIO · .
FEBRUARY, 1961
51
+1 0
-"
+s
"I
0
5D.
....
:>
-s
~
• 1,..00'
V
~
0 - 10
....
~
- 20
'" - 25
20
---
V
~ - 1S
.,.1'"
~
~
,
.
100
'"
1000
I
s~p~~~~b~ -
10000
Fig . 4. Measu red
ou t pu t of Shure
St ud io Dynetic ca rt ridg e (solid li ne)
an d separa t ion
(dotted li ne).
'0000
FREQUENCY IN CYC LES PER SECON D
well as one of the output circuits on the
mono unit.
Figure 3 shows the M216 model, which
has an over- all length of 14%, in.; M212 is
a shorter model with an over-all length of
11-5/16 in., and is perfectly suitable for
the usual home tur ntable. The bearing on
the vertical axis of the arm is a ruby, providing a minimum of friction; the cartridge is carried on two additional ruby
bearings (actually four separate bearings,
since there are two sleeves and two caps).
Compliance is claimed to be 9 x 10'" cm/
dyne, which is relatively high. The output
per channel, feeding into a recommended
load impedance of 47,000 ohms, is approximately 4.5 mv for a stylus velocity of 5
cm/sec at 1000 cps. Figure 4 shows the
measured response from a test record cut
with constant amplitude up to the turnover frequency (500 cps) and at a constant
velocity above turnover. The two channels
measured within 0.8 db of each other
throughout the range indicated. Separation
is greater than 25 db · at 1000 cps, and at
no place is it poorer than 10 db.
One of the featur es of this arm-cartridge
combination that attracts us most is its
ability to track the record groove when
used in a typical pull-out drawer turntable
mounting. Several types that we have tried
would j ump out of the groove as the drawer
was opened or closed; these were especially
susceptible to vibration of the floor as one
walked (or jumped up and down) in front
of the cabinet. (We can see no reason for
j umping up and down in front of the cabinet, but it seemed like a good test.) In no
case, however, was the Studio Dynetic
affected. It was still not posssible to slam
the drawer after putting the stylus down
on the first groove, but it could ·be closed
without any jumping whatsoever, and without a great amount of care being required.
While most modern car tridges measure
reasonably well, t here is often some difference is sound quality that the measurements do not show up-Which only indicates that there are some things which we
are probably not measuring. But for
quality of reproduction from a subjective
standpoint, we feel that the Studio Dynetic
is exceptionally good. When this is coupled
with excellent tracking ability under severe
vibration, it becomes the logical choice for
many installations.
B-27
laterally. Thus, for truly fine stereo performance, a turntable must have very low
rumble. Of course wow and flutter must
also be exceedingly low, but these problems were solved satisfactorily in monophonic days. An interesting note here is
the' strip chart that is supplied with the
model 440. It is a recording of t he final
test for wow and flutter on the specific
unit. The interesting aspect of this, aside
from the superb performance recorded, is
that Fairchild is so confident of its manufacturing skill as to provide the actual test
performance for each turntable it makes.
The 440 makes a rather handsome package mounted on the special mounting board
and base available as optional extras. In
addition, the mounting board is isolated
f r om the base by means of four special
rubber feet; the board just rests on these
feet, held down only by the ""eight of the
components mounted on it. The visual effect of this arrangement is a little disconcerting at first because, until one examines it more closely, the mounting board
seems to be floating above the base.
Speaking of mounting, the entire mechanism- motor, turntable, controls, etc.are monnted on a rigid U-channel which,
in turn, is attached to the board. The
motor mounting is isolated from the turntable to avoid rumble. The use of the
U-channel makes installation of the 440 a
rather simple procedure. It took us about
3 minutes with Fairchild's mounting board.
A feature of this turntable is that it is
belt-driven-and two-speed. The speed
change is accomplished in a simple manner;
the belt is straddled by two wire "fingers"
which pnsh it to one or the other of the
steps in the two-stepped motor shaft. Each
of the stepped surfaces is slightly crowned
so that when the finger pushes the moving
belt, the crown helps it work its way to the
other step. This system works well unless
thE> belt stretches .
The 440 uses a 4-pound turntable similar to that on the Fairchild model 412.
This turntable is balanced and rides on
a micro-finished ball-thrust bearing in a
nylon seat. The main shaft is micro-honed
and rotates in a polished babbitt bearing.
In order to satisfy onr own curiosity about
the balance and freedom from friction, we
leveled the turntable, removed the belt, and
rotated the platter by hand. The turntable
continued to rotate for nearly 3 minutes.
Although this is not an accurate test, we
have beeu doing this on similar rotating
equipment for years, and find it a good
rule-of-thumb indicator for rotational performance. On this score the Fairchild rates
excellent.
All controls of the 440 are located on the
top of the monnting board and include a
speed control as well as an on-off switch
and the speed-change lever. The speed control can vary turntable speed by as much
as Ph per cent. It does this by applying
d.c. to the motor windings.
The test chart provided with the turntable is ample proof of the practically unmeasure able amount of wow and flutter in
this t urntable. Nevertheless we tried a
listening test using several records reserved
especially for this purpose-piano records
for wow and violin performances for flutter
-and confirmed the results of the test
chart; neither wow nor flutter is detectable
to the ear. Rumble, both lateral and vertical, is 56 db below 7 cm/sec at 500 cps.
The 440 achieved operating speed within
one revolution as verified by the stroboscopic disc supplied with the turntable.
One minor annoyance with this type of
disc is that a fluorescent or neon light
source should be used, and such sources are
not always easily available where the turnta ble is located; it wasn't in our particular
situation.
In operation in our listening area, using
the Fairchild mounting board and base,
there was no acoustic feedback discernible.
In addition, it is extremely handsome. We
are often willing to forego appearance for
the sake of performance, but it is all the
more enjoyable when we can have both. It
will soon be available in kit form.
B-28
FAIRCHILD 440-2 T URNTABLE
The Fairchild model 440 is a 2-speed
belt-driven turntable designed to provide
performance suitable for the rigorous demands of stereo records. We are all too
familiar with the excessive sensitivity to
rumble of stereo pickups. This is inherent
in the necessity to track both vertically and
52
Fig. 5 . Fa irchild 440-2 two-speed bel t d riven t urn table.
AUDIO
•
FEBRUARY, 1961
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- to several loudspeakers located anywhere in the home!
RP-40 Specifications: Frequency Response - Idb, 18 to
30,000 cps; Output - 20 watts per chandel, 40 watts combined; PM Sensitivity - 0.9 p.y for 20 db quieting; AM
terminal sensitivity - 1.2 p.v for .5v output; Distortionless than 0.8% at full output; Hltm Level- -80db; Dimensions-16" x 13Yz" deep x 6".
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BOGEN-PRESTO
Desk A-2 - Paramus, N. J . • A DIVISION OF THE SIEGLER CORPORATION
AUDIO
•
FEBRUARY, 1961
=.
:
-
60·21
53
H. H. SCOTT LT-10 FM
TUNER KIT
During the New York High Fidelity
Show, way back in September of last year,
we had the opportunity to observe two
pretty young ladies constructing FM tuners
in the H. H. Scott booth. At that time we
were impressed by the relative ease with
which these young ladies were manufacturing FM tuners. Of course, b eing old cynics,
and having built many an FM tuner kit in
the past, our first reaction was to disb elieve
what we were seeing. We couldn't prove it
but we were convinced, within ourselves,
that these two builders were really technicians in shapely clothing. Perha ps this is
just our own personal r eaction to all the
superlatives we encounter nowadays.
Anyhow, since that time we have constructed the LT-10 ourselves-and most
humbly apologize for our base thoughts_
This kit is the simplest to build we have
seen to date. It took us less than 7 hmtrs
to put it together, and that includes alignment_ In addition, since completing this
unit, we have operated it almost continuonsly for nearly three months without even
a hint of difficulty. Without hesitation, we
would reco=end the H. H. Scott LT-10
FM tuner kit to the beginner as well as the
more experienced audiofan.
Before continuing, we should mention
th at in th e r ealm of kits the H. H . Scott
LT-10 exemplifies engineering of the highest calibre. Surely only the most sophisticated engineering thinking could design
a kit as simple and foolproof as this one is.
Although virtue is said to be its own reward we do hope that such excellence receives appropriate recognition.
Up to this point we have confined our
discussion to the LT-10 as a kit. In r eality
there is a more fundamental question to be
answered, "How good a tuner is the LT10'" To put the answer in some frame of
reference we will point out that the LT-10
is essentially a model 314 in kit form. That
makes it a good FM tuner. It utilizes the
well-known silver plated front end and the
wide-b and circuitry which is a f eature of
all H. H. Scott tuners. During the several
months we have had it in operation no less
than ' nine different people-guests-have
had to be shown that an FM tuner was the
music source, and not a record. We should
mention that it is not common practice to
count guests in our home-but we were
Fig . 6. Completed H. H. Scott model LT-' 0 FM tuner kit.
impressed by the relatively large numbers
involved.
F'ig1tre 6 shows the L'r-10 completely
assemb led in its case (not supplied with
kit). The tuning meter shown on the left
front is quite sensitive and is illuminated
so that it is easy to read at night. The
tuning dial is also illuminated and unusually easy to read. At night the edge-lit
plastic tuning dial is handsome as well as
functional. It should be noted that the
action of the tuning dial is extremely
smooth and sensitive, although just a shade
too sensitive for our taste. We like a little
more positi,' e feel. In comparison, it is like
the power steering employed on Chrysler
cars as contrasted to that used by General
Motors. We prefer th e more posith'e feel
of the GM type.
Circuit Description
In most respects the circuit of the LT-10
is complet ely straightforward: cascode r.f.
amplifier utilizing a 6BS8/6BQ7 A; 6U8
oscillator-mixer; a pair of 6AU6 i.f.
stages; and a limiter consisting of the pentocle section of a 6U8; the detector, which
is the unusual feature of this circuit, uses
a pail' of 1N294 diocles; and the audio output is the triode section of the 6U8 limiter
used in an anode-follower configuration.
The anode follower here provides some additional gain and permits cables up to 70
feet in length.
1'he r eally different feature of this circuit, as we mentioned previously, is in the
detector stage. In co=on with all of the
H. H. Scott FM tuners, the LT-10 uses a
ratio detector. One of the advantages of the
ra tio detector is the additional limiting it
provides. Another, and probably the greatest, advantage is the wide bandwidth obt ainable. The 2-megacycle bandwidth of
this detector is, to a large extent, responsible for the freedom from drift of this
tuner. For this reason the LT-10 does not
provide a.f.c.-nor do any of the H_ H.
Scott tuners_ From our experience, it is not
needed.
Although it doesn't actually pertain to
circuitry as such, a great deal of attention
has been paid to r educing circnit losses.
Tllis is evidenced by the silver-plated front
end and the copper-bonded-to-aluminum
chassis. Details such as th ese permit the
circuit to operate at its full capabilityprecautions which are especially important
ill r.f. circuits.
Alignment
Alignment is the most difficult stumbling
block facing the audiofan who builds an
FM tuner kit. Precise alignment requires
the use of various types of test equipment
which are not usu al audiofan gear-an FM
signal generator and an oscilloscope to
name some. There have been many schemes
devised to help solve this problem- pre-
Fig. 7 (left>. Tuner is aligned with H. H. Scott system requiring neither special tools nor test equipment. Here the top slug of the
limiter can is being adjusted. Fig. 8 (right>. All parts are mounted on Part-Charts in order of assembly.
54
AUDIO
•
FEBRUARY, 1961
.,
\
the giggles
_ Put one little girl together with somethingthattickles
her funny bone-and out comes the purest, merriest
of sounds. _ We don't propose there 's anything quite
as nice. But we can tell you about another kind of
purity of sound that's worth discovering. _ Make
your next tape recording on Audiotape. Then listen.
_ Audiotape ... it's wonderful! It has less distortion,
less background noise, more clarity, more range
than other tapes, because it's made to professional
standards. Let it be your silent (but knowing) partner
in capturing fresh, clear, memorable sounds. (Like
Sissy's giggles, for instance.) _ Remember: if it's
worth recording, it's worth Audiotape. There are
eight types . .. one exactly suited to the next recording
you make.
GlIcl.iotae,!'
" IT SPEAKS FOR ITSELF "
AUDIO DEVICES INC., 444 Madison Ave.• N. Y. 22. N. Y.
Hollywood: 840 N. Fairfax Ave., Chicago: 5428 N. Milwaukee Av&.
Fig . 9. Th is is the way it looks when it is
first opened . Tag at lower right is supplied with kit to be pasted on after completion.
assembling and pre-aligning the i.f. stages,
printed cir cuit boar ds, using the tuning
meter, and so on. By and large t hese
methods have been increasingly successful ,
although still not as precise as the factory
procedur e. The method devised by H. H .
Scott engineers, alt hough not necessarily
more accurate, is decidedly less critical.
This is one of the bonus extras accr uing
from the wide-band detector.
The procedure itself is really simple. The
sequence is as follows: the second i.f. can
is tuned for maximum indication on the
tuning meter, the bottom slug being tuned
before the top slug; the limiter can is
tuned the same way (see Fig. 7) ; the first
i.f. can is also tuned the same way; then
t Ile r.f. circuit is t uned for maximum deflection of t he tuning meter; finally t he
detector can is aligned, again adj usting
the bottom slug first. Adjusting the top
slug is the most difficult procedure of all,
and it is at this point that the "piece de
resistance" is un veiled; an ingenious
method utilizing a light bulb. The bulb,
which will later illuminate the tuning indio
cator, is connected to the speaker terminals
of an audio amplifier to which the tuner
has been cOllilected.
Next, the bulb in its holder is then placed
between an i.f. can and the shield over the
tuning capacitor. Now the slug is rotated
and the resulting brightening and dimming
of the bulb noted and compared with the
patterns illustrated in the manual. Then,
all that is necessary is to locate t he slug
at a particular "bright" point which is
identified in the instructions. This is a
simple procedure which actually produces
good results. We checked the setting with
au FM signal generator and an oscilloscope
and found it to be near perfect-within a
cat's whisker. Actually we didn't "touch
up" the alignment until some weeks later,
purposely, so that we could listen to it
with the original alignment. We could not
hear any difference after the tuner was
aligned using test equipment.
t hese are minimwnn specifications. It should
be noted that H. H . Scott adheres to IHFM
ratings. For example, a usable sensitivity
of 2.5 microvolts is claimed. Some other
manufacturers use a different rating system which makes it seem t hat their tuners
are more sensitive. In reality, if the same
conditions were used to rate the LT-lO, it
would appear to be much more sensitive; or
conversely, if the other tuners used the
IHFM ratings, they would appear to be
less sensit ive. Apparently, out of conviction
that the IHFM ratings should become
"standard," H. H. Scott is adhering to a
rating system which seems to place his
product at some disadvantage. We cannot
help but admire such integrity.
One of the things we have been amazed
at with this tuner is its ability to pull in
stations with a short piece of coa:'{ial cable
for an antenna. This occurred when we
connected t he test cable from our FM signal generator to the antenna terminals.
With no more than this l8-inch piece of
coa.."{ial cable we were able to receive any
station in the New York City area. With
the dipole antenna supplied with the kit we
received a station in Connecticut which is
about 50 miles away.
ERCONA NORDIC
SPEAKER SYSTEM
If we weren't already cOllvinced, this
diminutive speaker system would certainly
prove that size i sn't everything. When we
first removed the Nordic I from its packing
we were certain, wit hout even hearing it,
that we couldn't expect too much from
such an unusually small enclosure- a mere
71,4 x 10% x 22%, inches.
Before going into further discussion of
its sound qualities, we would like to say a
few words about the appearance of this
speaker system. Without knowing why, we
kuew that the cabinet had been manufactured in some Scandinavian country the
first moment we laid eyes on it. (It was
manufactured in Sweden.) We still don't
know why, but we can g uess t hat it is due
to the way the wood is finished. The unit
we have is mahogany (it is also available
in teak), but it is not a variety we see very
often; it is reddish in color like Philippine
mahogany. Anyhow, it is hand rubbed and
the resultant cabinet seems to have a warm
glow about it. Very tastefully done.
We have just demonstrated the difficulty
in using words to describe the quality of an
object where there are no rules to go byindeecl there can be no rules in such a subConst ruction
jective area. This is the same problem we
Figu1'e 8 shows some of the Part-Charts are faced with when we try to describe a
on which all the loose parts are mounted.
speaker system. For example we described
Each chart has a key number which
the sound quality of the system as excepmatches a particular page in the instructionally clean. By t IllS we mean that there
t ion manual, and in addition each compo- is a high degree of naturalness about the
llent on the chart has a key number which
sound it produces; highly listenable and
indicates the exact assembly step where it
non-fatiguing. It reminds us of the Saab
is used. T o make the assembly procedure
automobile (another Swedish product)even more foolproof, the illustrations renot an ounce of fat on it, and with perlated to each assembly group are in colors
formance way beyond its size.
so that the parts are placed visually as well
The bass sound of the Nordic I can best
as by description. Unlike many instruction be characterized as tight and non-boomy;
manuals, this one is extremely easy to read. it does not have the depth and richness a
Figu1'e 9 illustrates the appearance of large system such as the Patrician which
the LT-IO when the box is first opened. One was discussed last month. Nevertheless, as
of the innovations in this kit is that it can far as it goes, it is smooth and solid. The
be constructed in the box. This is a great source of bass is an 8-inch speaker with
convenience for those whose construction
patented, multi-layer, cone construction.
facilities are limited. Note the small label
Apparently the cone consists of several
in the lower right corner of Fig . 9. This layers of different fibres, alternately hard
self-adhesive label is to be filled out with
and soft, in a sor t of D agwood sandwich
t he constructor's name upon completion of
configuration. Sounds tempting.
the kit and attached to the chassis in an
The crossover frequency is 7500 cps alappropriate position. We presume that this
t hough the 5-inch tweeter actually starts
is meant to confel' status and recognition
operating at 5000 cps. The tweeter is
upon the kit-builder. It may at that ..
mounted on a rigid, solid, die-cast frame
which makes it an unusually rugged unit.
The under-chassis view of this kit is
The music power rating of the Nordic I
slightly unusual; it is just too simple for
an FM tuner. We are used to the "rat's is 20 watts. We used a 10-watt amplifier
nest" maze of wires common to most FM to drive it and obtained all the sound we
could stand-in level, that is. We might
tuners. In contrast the wiring of the LT-IO
add that the sound did not seem "forced"
seems barely appropriate for a baby rat.
I n summation, the H. H . Scott model at high levels.
In sum, then, the Nordic I is ideal for
L T-IO is an excellent FM tuner kit which
the audiofan with limited space and a
is unusually easy to build. It is well within
the capabilities of even a beginning kit modest budget. Its sound quality is excelbuilder- providing he follows the simple lent and should provide many hours of enjoyable, nOll-fatiguing, listening.
B-30
instructions.
B-29
Fig . 10. Ercono
Nordic I spe a ker
syste m.
Performance
The performance specifications of the
LT-IO, as stated by the manufacturer, are
quite gooil: especially in light of the explicit guarantee by the manufacturer that
56
AUDIO
•
FEBRUARY, 1961
This is' the new JBL S6 Linear Efficiency Sys.'
tern with a new 15" low 'frequency unit, new
dividing network, new high frequency driver,
and new horn and acoustical lens. The new
LE15 is made with a 4 ~' edge·wound copper
ribbon voice coil, long·throw Lans·a·Loy sus·
pension, rigid" cast frame designed for mount·
ing from either the front or the rear of th.e
baffle. This is the only 15" unit on the market
capable of linear cone excursi<?n of % inch.
Free air cone reson'ance is approximately 20
c.p.s .. The new LX5 Dividing Network matches
the LE15 perfectly to either the new LE75 (in
S6· Kit) or the new LES5 (in S7 Kit). Crossover
is 500 cycles. The LE75 and~ LES~ \Ire labora·
tory stan~ard high frequency drivers with silver
impedance compensating rings; voice coil and
pole piece assemblies are held to previously
unattainable tolerances. The new HL91 Horn·
Lens Assembly, specifically designed for the
new drivers achieves completely uniform dis·
persion over a 120 0 horizontal X 45 0 vertical
pattern through its full range from 500 c.p.s.
to beyond the limits of human hearing.
A sensational sight with sensational sound, the new JBL Olympus has been
enthusiastica\ly acClaimed at every preview for its unprecedented fiat, accurate
reproduction of the entire audio spectrum. The .olympus has remarkable bass
response . . . goes all the way down smoothly clean. It reproduces the lowest
fundamental in all its rich, original power. And does it in the JBL mannerwith precision articulation, accurate delineation. The new slant-plate acoustical
lens refracts equally all frequencies which pass through it. Not only does this
heighten realism from any listening point, but permits a new latitude in
speaker pl~cement in stereophonic installations; .
The C50 enclosure is styled with timeless elegance. Top edges are tapered
to slim the cabinet's proportions. The wrap-around grille disguises the sturdy,
heavily braced sides. Though the C50 is a six cubic foot enclosure, its bulk is
comparatively small when the magnitude of the system's performance is taken
into consideration, and the D50S6 might be accur~tely d~scribed as "a compact
system:' The new wood grille is shown above. Also, you have your choice of a
fabric grille.
Production of the new systems is underway. To reserve a pl;oximate place ,
on,the backlog, it might be advisable to get your name on,the list without delay.
PRODUCTS OF JAMES B. LANSING SOUND, INC., ARE MARKETED BY JBL INTERNATIONAL, LOS ANGELES 39, CALIFORNIA
AUDIO
•
FEBRUARY, 1961
5t
isolation in spaee of the single character
heightens his :Ilone-ness, the bunching-up
of two people into the other speaker d ranUltizes their togetherness. Given the right
material, this arrangement adds enormollsly
'(from page 15)
to recorded dramlltic impact. Similarly, you
may recoril two musicians on one mike a
do, in fact, share vel'y little common sound,
third 011 the other,
whether room li,'eness or the Mo unds going
You may, of course, try the next cateto the 0VIJotiite mi ke, Thq stand on their
gory, two performers on each mike, but a
own, withuut reconled livcuess, amI Ih<'y
lIIlIch more interesting variant of thE' Twomay indeed ue Vlayed back iu the ausolute
Point approach is that which trpats of
manlier, i.e., at the literal ,'olulne of the
groups. When YOll have a l:1rger number of
origiual so und, for a very litera I sort of
reproduction, each voice or, instrument lo- people to cope with you will be tempted to
try real stereo-i.e., to move your mikes
cated iu its own speaker.
back for an o,-er-all "sounrl-curtain" pickBut you will find, 1 think, that for genup, with everybody located in his rightful
eral ente rtailllllent and/or reprodueed impact the good old exa ggerations of ordinary position across the stage.
Don't do it I Don't even try. For you'll
recorded soulHI tierve !Jetter. The princivle
of "realistic dititortion" easily wins out very likply fniI. As I say, rea l stereo is
tricky and needs precisely right mike plaeeand you'll play your recordings genl'rally
much luuder Ihan the ur igiualM. We a lways ment and right acoustics, seldom of the sort
founil in living rooms.
do, in rOUlIl-size rt'cof(lingM.
Iustea d, di\"ide your people into groups,
In fact, here you have a rather special
Cluster one group around one mike, a nother
and unexpected dralllatic tool of great lIexiaround the other, all as close as convenibility for your playback sound. You may
ently possible, C~ote that as long as a few
vary the relative loudness of your two
voices-or instruments-are highligilted
channels for ea,'h performance, with astonclose to the mike, the listening ear will not
ishingly diffel'ent results! You have two
object to an "off-mike" sounil, at a disvolume controls, uot just one. You can adtance, for numerons othcrs. The contrast
just the playbm'k ualance between channels
afforcls audible perspecti ve, near and far.
o\"er a rolatively huge range, and you never
need hear your n'cording~ Iwicl' iu the saUle H is when all YOllr soulllis are too far off
way. New aud lluite surprisingly din'ereut, thnt the re~ord i ng is a failure.)
Inedtahly, in spite of the closest posyou'll adlllit.
sihle mike positions, you will begin to inFor instance, I maile one very pleasant
clurle an appreciable amollnt of general
recording, ,-i" this prin~iple, of a hoy with
room liveness, souud common to both chana low batis ,-oice singing a 'Iuipt bluI's song,
n~ls, in this sort of group recording, That
to an accompanying guitar. Followiug the
Will be enough . Don 't force the ster ~ o issue.
Two-Point systeUl, I put one mike right
next to the fellow 's nllHI! h, since he Rang at If you consistently avo id stereo via maximum group close-ups, you'll likely end with
a very low \"01 II III e. The other mike went
an appreciable tru e stereo effect in spite
close to the guitarist's fingl'rs, a COli pIe of
of you rself, Works that way.
,
yards distaut. You could scarcely hear the
Ana now for surrealiRm. What do you
"live" singer nrross the roolll; hut I hud
do if there are three or four groups~ Can't
playback effec·ts in mind. One rhannel
put two in one mike, The answer I found
picked up 95 per cent miee, the othp.r the
is simple. Just jump your mikds around~
same 011 gllit:H; the o,-erlap of sound was
from group t.o group, freely in the hand.
just barely au,lible.
_
What? Move the mikes in the middle of
On playback, the light bass voice was
amplified hugdy, and tUrJwd ont as a tre- a recording ' Professionals will swoon with
mendous, big, solid sound-this is an old horror. But that is exactly whnt I did.
For example, one evelling I took down a
mike tri~k_ The guitar recording was litlot of party singing, The gang started on
eral, absolute, lout could be pla~-ed at any
volume, from a whisper up to nn ominou,ly a musicnl round-four parts. Four groups.
What was I to do' I pointed mike No. 1
huge, hl'a '-yweight beating, almost or('hcsat, group No, 1 when they began the tune,
tral in impact. 1 was thus a hie to vary the
nuk e No.2 at the second group ns it took
combined channels for a whole gamut of
up the round in turn. Then when group
different musical effects.
No, 3 came in, I simply switched the first
Use your Two-Point close-up technique,
mike t hrough the air, at nrm's length, right
then, ad lib for a choire of liternl realism
over to that group, and the same with the
or free fantasy. Vary your playback-realism in one spcaker, falltasy in the other_ second mike f or group No.4, Needless to
say, both mikes pulled in large amounts of
A tiny \"oice on the right, a m:JInmoth
background singing and the groups were
monster on the left. Experiment with varimerely closer to a given mike by, say fifous musical combinations, ... You can go
teE'n or twenty per cent. But the mere effort
on and on.
on my part to get each mike as close as I
could to the center of each group ensured
Three Points and Up
(as the British sny) that th e over-all sound
When you begin, inevitahly, to experiwas alive and not overly off-mike.
ment with more than two sound sonr~es you
.A nd what happened with the flying
will edge into a less extreme hut even more
m!kesf I 100k('iI like a windmill, and ench
flexible category-it was here that I dis- mIke traveled dozens of yards throu<7h space
covered dual-channel surrealishm.
during the recording. But on the piayback
If you record two guitars and a singer
not a singer moved an inch. The whol~
you'll ha\"e to dh'ide your mnterial two to
g~ng seemed to be neatly lined up on a
one; but your T~,- o-Point technique is only WIde stage, to left and right. In fact, to
moderatp.ly modIfi ed. Keep the maximum
my amazement, this was a real stereo reseparation. On the mike that picks up two
corrling- surrealisti ca lly achieved.
Bou~ds, two performers, you')) move back
The principle is simple and interesting
a bIt, to take in both, Less literal in the
well worth taking to heart.
'
pirkup, with somewhat more room -sound
Th?ugh the recording mikes may move
(liveness), but e\"en so, you can follow the
errat~eall:>: and even wildly, pointing any
Two-Point Principle and you'll get a new
old directIon, front, rear, up, down side to
range of dramatic effects.
side, the playback sound reflects' almost
Record a three-way dramatic sequence
n~n e of. this, Tnstenrl , the illl:1ges move
for i.nstance, with two eharacters (clo"e~
slIghtly if at all, and most of the motion
up) ill one channel one in the other. The seems to be quite form al, from side to side,
AUDIO ETC
as on a stage,
Amusingly, everybody "looks at you" in
the playhack, reganllE'ss of positions in the
recording. A helter-skelter crowd of people
lounging all over a room, standiug, sitting,
fneing this way and thnt, emerge in a dualchnnncl rec'ording neatly lined up and all
facing straight forward! Thus you don't
have to arrange your amateur recording
perfopners in lines and ranks. Just take
them where they stand or sit, llIakillg ,,"'e
ollly that they bunch to some extent into
groups (as they usually do anyhow) for
the "xploring mike, close-up.
The strallgetit aspeet of this surrE'alistic
r ea lism tand it's lin eye-opener as to the
relation between recorded sound and live
originals) is tll:lt the rlllal-"llllnn cl meilium
will make proper, staid, rational rE'coTiling
out of the za lIiest mike antics you can
imagine. Anything goes. Anything goes,
that is, so 10llg as you make no attempt
whatsoever to be lite·m l. Tha t you cannot
do! No matter how hnrd you try, the two
sl'eakprs will take your spatial material and
r enrra uge it aeconling to their own principles, You can make only one mi Rtake :
too-distant miking. As long as YOll will insist uJlon sOllie part of your total roomful
of sound heing close to one mike or the
oth er, or both, you cannot go wrOllg nt all.
You Illay mo"e yonr lIIikl's C]uirkl~' anywhere you wi sh, to fulfill this c-ioscnesR, and
the 1lI0tion will he undl'tp ~tible. It cannot
be perceh'ed, in the play hack, ns motion; it
comes out instea d as a kinrl of professional
fade-lip, or fnde-out, 110,-e your mike
quickly awny from one voice or instrument
and the sound merely fniles clown unohtrusively in the playhack. A polished IInrl very
professioual sound it is, though to look at
YOllr mikes zooming hither and YOll, you
would not believe it possihle.
Knowing that anythiug surrealistic you
can do will merely add to the "realism"
and impact of your recording, you will
soon len TIl to follow up and exaggerate
your surrealism. During that musie,,1 songfest, for insta nce, T noticed one little fiveyear-olcl ecstntir·aIly singing away to himself as the others sang, making up his own
words and tune. I C]uiekly whooshed one of
my two olltstretrheil mikes ov('r to him
hold!ng it a few inches nbo\"e his hend (and
looklllg fixerlly in illlOther direction to ,listract him). The r esult was delightful anil a
great success in plnyback though the voice
was enormously blown up in size. A good
close-up.
*
*
*
Yes, there are other, more r easonable
( and more difficult) types of dunl-channel
mike techniC]ue for home use, including
careful, ~aleulflted semi-pro st('reo. I'll
r elegate th em to a later moment, including
an old fa vorite ree.ording device of mi ne
now enthu siastically revi ved-true binaurai
recording for earphones_ I'll never tire of
thnt, and I'm now making new con verts
among those who hnve been subjected to it
for recording purposes.
My most spectaeular recording to date
I'll let on, was a t ape of an entire Thanks:
giving day dinner for 35 people, straight
throllg? from c~cktails to d ishwashing,
done bmaurally VIa two mikes draped over
the back of a corner chaise lounge. I just
let 'er run. Afterwards, I sat myself in the
same chaise lounge at the same spot and
heard the entire party all over agn in in my
phones, conversation by conversation. Fascinating.
But b,efore your Mr, Average Home T ape
User tnes that (an d he'll need a pair of
phones for every listener), by all means
urge him to, try just plain, ordinary, simple Two-Pomt Close-up home re~oriling.
It's marvelous fun, and the "surrealisticer"
the better.
n:
AUDIO
•
FEBRUARY, 1961
Does the music from your high fidelity system sound clouded
by noise? Faithful reproduction requires that records be
scrupulously clean. Even factory-fresh discs contarn groove
dirt, as you can easily prove.
After an exhaustive six-year test of record cleaning products, C. Victor Campos reports in the authoritative American
Record Guide: "The only product that I have found which
~
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AUDIO
•
W
FEBRUARY, 1961
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59
'\
RENAISSANCE AND BAROQUE
-" Spanish Music of the Renaissance. New
York Pro Musica, Greenberg .
Decca DL 9409
The Pro Musica, under Noah Greenberg,
has developed . into a remarkably efficient
unit of production for the reconstruction of
"old" m usic into practical modern perfOl'm a n ce. It has built up its own music library,
bought' a fl\scinating brace ~f old ins.truments- bells virginals , harpsIChords, vlOls,
portative , or~ans-has an office and a mailing
list, a mUSicologist to dig up the music and
prepare It for mass-production . . . .
The group 'n'ow 'glves' h un'dreds of concerts
and its repertor y burns u p old music almost
as fast as TV burns u p its material. The
performance Is thoroughly pr ofessional, impeccable as to notes and tech,nique but a
bit on the casual side as to Dmsical penetration-there just isn't time. Not even a
group of geniuses could turn out music of
so many styles a n d periods at the rate these
people do withou t running into a bit of
this trouble. And yet, I'd say, they are growing, as a group, finding more and more how
to blend their modern personalities and
modern trained voices into a hypothetical
unity that must evoke musical sound that is,
remember, an unknown quantity. Nobody
knows exactly how much of this music actually sounded; the best of scholarsh!p still
leaves enormous leeway for variatlOn, in
t empo, In dynamics, phrasing, balance, and
especially In vocal tone qua lity.
The group varies in detail. The new
countertenor, Robert , White, is a splendid
addition and, at the momelilt, .the most persu asively musical singer in the entire group.
The instrumental music, closer to a known
sound is on the whole better than the vocal,
which' still su ffers from the modern operaticstyle loud voice qu ality. T he choral motets, unaccompanied, have not freed themselves f r om
that tell-tale march-time rhythm that pl agues
modern renditions of the old works (and
reduces them t o rhythmic dullness).
You'll be surprised at the expressiveness
of "old" Spanish music as here so vibrantly
brought back to life, if you are a follower
of the more familiar Italian, F lemish, and
French music of the period. Wonderful material. My copy was mono but I assume
that this recording Is also available in stereo
(that would be DL 79409) .
Tavern Songs, Vol. 2 . Deller Conso rt.
Vanguard BGS 5030 ste reo
The Catch Club. Randolph Singers.
Elektra 204-X stereo
If you catch gl ee fever, catch fever, round
fever, you are a plague to your neighbors
and a pest to your friends , until you dragoon
them into joining your catch singing. I know
the species from its present-day practitioners,
n o less ardent than the orig inal gentlemen
who were nu ts on catches back in the 17th
and 18th centuries; no two of them can
be together for a few minutes without startIng in on one of these musical jollities;
they haunt the libraries and ransack their
*780 Greenwich St., New Y ork 14, N . Y .
acquaintances for new music to try, and
occasionally-an unheard-of faux-pas-they
allow a girl to sing with them.
But that is only because iu the old days
they used countertenors, and counterteno~s
today are only beginning to be grown agam
from seed. Not yet enough of the gentlemen
sopranos and altos to go 'rounel.
A glee is just a sweet bit of male harmonizing the ancestor of barber shop. A round
is a ;ound, a canon which goes 'round an.d
' round, everybody singing the same
mUSlC
but at different times. A catch has doubleentendreB, blanks here and there so that unmentionable meanings are produced via interaction between voices. Good clean fun,
and in ,thpse ,days you c<!uld s~y . alm,ost
anything between friends in music, and you
did.
The two collections h ere suffer to varying
exten from a major difficulty with all professional ,p erformance of this older '!lusic,
the clearly different concept of a "tr~itred"
voice that exists now as compared with the
voices that must have sung these ribald
little works. The human instrum ent can take
an amazing variety of forms and styles, with
training, a s we ought to know. Today's rich,
heavy, wobbly voice, loud and inaccurate ~n
pitch, is just plain ill-suited to suc}l mUSIC.
Amateur voices, much less impresslve, nevertheless make hetter harmony and clearer
sense ou t of the music.
The Dellers do a more easily appreciated
job with the music and their Singing is
lighter, more sprightly. beter blended. Both
groups are well aware of the high comedy
and low suggestiveness of the songs and do
well in projecting the same via the cold, impersonal mike! Texts-all that are fit to
print-are included.
ts
Madrigal Maste rpieces. The Re naissa nce
in France, Italy and Engla nd . The De ll er
Consort.
Vanguard BGS 5031 ste re o
The Deller Consort is the ra nking British
production unit for old musi c and its volume
is probably as great as that of the New
York Pro Musica (and the Belgian Pro
Musica under Safford Cape, to my mind the
fin est of all these groups). The Dellers keep
to a somewhat more limited range and feature .largely Singing, minus the profuse instrumen tal variety offered by both the other
groups.
.
This .collection, ' Il, cross-section of. the ,16.th
century and early 17th centuries, includes
some of the most wonderful music of the sort
ever written, ranging from the sweet and
gracious French love music of Lassus (Mon
Ooe1l,r se recommande a VOlts) through some
exquisite Monteverdi and a brace of solid
British fare. The Dellers, too, suffer from
assorted wobbles and over-brilliant tone production, but Deller himself has no vibrato
at ali, when he wants to dispense with It,
and in many places his ilirection produces
a perfect blend. The ensemble is more pliable,
softer, less metallic, than that of the New
York group. Also, perhaps, both more musical and a bit more eccentric.
I think 1:here is much meaning in these
works that has not yet been extracted; but
their best sense is surely available in this
well-styled production.
Handel: Acis and Galatea (abridged),
Soloists, Oberl in Choir, Came rata Academica Des Salzburge r Mozarteums,
Paumgartne r.
Epic BC 1095 stereo
(mono: LC 3724)
This is a curious mixture in the performance, and most revealing, too. T.he sing:
ers are student s of Oberlin College III Ohio,
spending their entire junior year in Salzburg; the orchestra Is the local academic
outfit attached to the Salzburg Mozarteum.
The conductor, Herr Paumgartner, is the
Salzburg factotum, a first-rate conductor ~r
Moz.art opera though a rather .academl; _
leader of pu rely instrumental Mozart- as eVldenced on numerous earlier Epic r ecordings.
There is much sweetness and light described in the record notes concerning this
"providential conjpnction" of unlikely forces,
bu t my ear tells me a different story: The
chorus ldds sound all too much like a
healthy American chorus, complete with
midwest accents and a brash, unsubtle loudness as though this were the "l\lesslah"
or the Star Spangled Banner, which it js
not. The solo voices, earnest, often very
expressive but just as often making rather
pitiful boners in tone quality and pitch,
would appear to be Oberlin studen ts though
Robert Bruce, the giant Polyphemus, produces a more professional job. The girl,
singing Galatea (Maria Hurvey) , hus a nice
sort of advanced musical comedy voice; the
bo~' . (Richard vnn Vrooman), the Acis, sings
manfully for the most part but in some of
the rapid portions he clings fo r dear life,
on the edge of disaster.
I might of course be wrong, but to me the
whole vocal element in this production
smacks of student operations, and too much
so. There is practically no feeling at all for
the delicate pastoral style which tbis fiowery early Handel seeks to promote. It Is
done without delicacy in a conventionally
loud "oratorio" manner; the whole simply
smacks of narrow, over-technical musical
education, of voice production not yet perfected, at the expense of mus ical knowledge
dismally absent.
And what of the Salzburgers and the expert Mozart orchestra man, Dr. Paumgartner? He runs this show In steamroller fash ion, ploughing forward as thou gh to get it
all over with. I can only guess, but my
strong. feeling is that Herr Paumgartner
was driven to de,s peratlon by this ,impossib11l
mixing of studentry and professionalism and
reflects his musical impatience in a headstrong, unmusical accompaniment. What
else?
Maybe--just maybe--tbis Is the course of
too many of our vaunted international cultural exchange programs. The intent is
noble, a lways. But are the results?
Handel: Organ Concertos, vols. I, II (complete). Walter Kraft, Eva Hoeld e rli'n ;
St uttgart Pro Musica Orch., Rei nhardt.
Vox Boxes 23, 24 {3 each}
This compound reissue set is worth mention for the nice sound quality achieved
from tapes that, I figure, must have reached
AUDIO · •
FEBRUARY, 1961
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AUDIO
•
FEBRUARY, 1961
61
me in LP form back aronnd 1954. A number
of Vox Bets have been comhined h e re to
cover the whole set of concerti. and hence
tbe pair of orl(llnists.
These are lh'ply. straigh tforward playIngs, with an intelligent r pco rdell balance
between the organ and on·hestra. the organ
l>ig eno ugh hu t not, as in some r,'cordln):'s,
so close as to dpstl'oy the sense of ensemble.
The orchestrn. though In a bll( SP"('P. is
leaner nnd lh'elie r than thnt in the Columhin Biggs serlt,s 11I)(lpr Roult nnd. on the
wbole, is a bit more modern in its playing
style.
T compared some of the old r eco rding with
the reissue nnd was gratified to find . in Ild(lition to the adjustment to RIAA (en"ily
noticpahlp). n smontJwr ROund nnd, 1110st
notably. much improved su rfaces, Our present
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QUARTETS AND BALLETS
Gould: St. ing Qua . tet, Opus 1. The Symphonia Quartet.
Columbia MS 6178 stereo
If the yonng composer of this qnartet
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1}l'Opert~· . Culnmhln ml/!ht not he promoting
this partIcular recording, But tbe music is
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62
dintll ~e
Beethoven: The Middle Quartets (Opus
59, Nos. 1-3; Op. 74; Op. 95). Budapest
Quartet.
Columbia M4S 616 stereo
(mono: M4L 254)
A2A
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of
early tl'll ining in the thpn pxrltlHlvplv "pontemporllry" ml1"lc tl.llt "'flS a ll hp I'vp~ hpllrd,
Compo.inl( a 11(1 pprfnrmlnl( wprp line, A. a
piflnlst. todny. (innlc!'s performing refipcts
our time •• from Bach to Webern. Can his
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f'x :' l11plf' of thp work
inff ll PnC'f' Otlt of tl1f1ny n (,pnt nry.
How (>Isl'. In a ll honPHt,? If ~lozart'" PIIrly
compositionR wprp ImpPC'cahlfl, FIn W;)N his
Ash for a Free Demonstration at your Nearest Franchised Roberts Dealer:
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n:-t nil
an unusua l musical mimI in tbis day and age.
It Is hoth dl1l'u"e lind nniye. ye t complex
nnd ad \'Ancl'd: its inconcJu"iYe st~' 1 1' stems
most pr()mlnpntl~· fro m earl y Sphopuherg,
but s110w" the inl1upure of a do>.en othprs,
from Bach ancl late-Rel'thoven to 81r>ll1SS,
Franck. and almost An,body else of a serious
na ture yo u Clln mpn tlon !
In oth pr WOTlI., thl" Is n hnlf-hnkPll work,
but of great earnestness and Intensity. striving for the highest sort of expression In a
g reat tradition and hitting it off momentarily
in many quite startlingly powerful passages.
Like many an early work f,'om a strong musical minrl. it throws the book. yet mnnllges
to be verbose and diffuse too, Fugues. contrapuntal structuring. largl'-Acnle sonata fOI'm,
pregnant motives 1\ la Beethoven (lnst quartets). a motto of foul' notes out of whicb
everything in sight and sound is deriverl-chromnticisms. long passages of ominous
tr~mulanrlos. anrl. of course. the obv iously
prl'gnant fact that this is a quartet . not a
sym phony: in ten seconds you will know that
the quartet fo.'m is he l'e chosen as the hil(hest
form of musi cal expression. It's that kind of
muxic.
TI. e rc are passages that sonnd mprely inept
to m e and t here is n vast sense of drnmatic
anticlimax. t hanks to too-hard working of
lofty mat prinl. Bnt ns T say, thprp are "",1denly striking passages too--often those
which arp furtlwst oul in stylist ic incongruity, snch as thl' Brnhm"-Iike second
theme. The whnle work is a slncpre a nd
hl'nrtpning change f rom too mnch Rnre hnt
pmpty tp,'hnlnnl' liS rlispln,pcl In II tllol1<lIn(land one noisy. skillful. contemporary pie(·es .
Tlli". 1'<1 slly. is IIII\\' 11Il h onest IlPrform er
. 'wulrl ine\'itllhly hpgin to writp. in 0111' time
The Budapest Qual'tet Is rpcorcling the
Beethoven Qnnrtets for thl' thit'd time Billre
joining Cnlnmhi a In lhp 7R-rpm dll,s (nnd
he fo r e that tlw,\' did splendid work for RCA
Victor). The gl'OllP is now thl' "Bil(l(Pst
Nam(''' in the chamher mu sic hURinp~~ nnd,
by dint of sheer pa s"ing time, is now clearly
a middle-aged quartet, if not an elderly one.
(8pecificfllly tbe oldest is 62, tbe younl(est
51). A ll of tbis sbows up in this new album,
which
is
dollt'(i up
ill II
ple asing
mHIIIH'r
with
a ion/.: essay on tbe Budnpe"t eXl'erpt .. d from
the Xew Yorker. by Joseph Wecl!sherl(.
Tbe Budapest Beetho\'en sbows botb the
adnlntnges and dislId\'antagl's of long experien\'e on the highest plane. Tbe interpretation", per se, CIW scarc\-Iy be hent by
a ny olher living, quartet for "beer econumy
of 1"'e"entaUon. for the deptb of 1II1<lerstanding on emotional and arcbitectonic
pluw.-'t3. The pluyiuJ; itself, however, ueg ins
to show the rigors of time-not in any fading of intent, l>ut simply in a softening of
the sba rp ou tline of tone. in weak notes
bere and there (utterly unimportant. bnt
there nevertbeless), in a sligbtly tbin, metallic tou e of ensemule as comjJal'ed to the uuetuon" richnes" of some of the more selfcouscious younger quartets,
Culumhia hilS nicely solv ed the problem of
quartet stereo--wbether to buncb tbe players in the m.d<.lle for a semi-mono effect or
to spread them out, witb a risk of the inadmlssaule "straigh t line" eU'ect, all the
vluyers lined up in a roW. Here, a miid but
dellnite bi):, Ih'eness b elps to place tbe group
between the two "peakers and a bit back;
yet tbere is enoug-h separation so toot tbe
first fiddle is dellrly more to the left than
tlte vlulu aud the same wltb second fiddle
and cello,
'iou'll find that a very delicate adjustment of thl' halance COlltrol is required to
get tbe qual·tet squarely in between your
two tlpenkt'l'::it UI:H:mmiug us ulwuy::; that you
bu\'e lhem fa r enuu;,;h apart to pro\'lde n
respel'taille stereo ell'ect. (More tltun six
feet ill most Ih'!ng rooms.) If you ba Ye on&pl~c~-cHbinet Slereo you migbt us well forget uuout ull this; your music Is mostly
wuno, und tbat is tbat.
Ballet Music from the Opera. Paris Conservatory Orch., Fistoulari.
RCA Victor LSC 2400 stereo
,
Maestro Fistoularl a ppears to be a n impressive conductor for ballet-type music of
t lds pleasuntly old fashioned sort, jndglng
frum this und the London-Richmond WOIlO
releases I've been listening to. Thi" Is a
grand stHeo recording, a clean, peppy but
well-llIHnnered performance-rath er surprisin/.:I.v nPllt Hnd In tu ne for a l.' rpnch playiug--which does the best tbat aan be done
fur th~ mush- without pushing it too hurd
into s umething it isn't. lmpeccahle tempo,
phrasing, lovely balances e \·erywhere. iugrHtiatlng sount! of smoothly played violins,
Nice hi fl. too. with tlte familiar blls"-d rumand-c.nnbal tillllnps most effectively recor(led.
'I'here's I.'rench and Italian dance music
from
"\YiIliuUl
'Tell H
"Kbovuntchina"
"Sumson and Delilah," 'aud "Aida."
'
Tchaikowsky: Swan Lake (complete). London Symphony, Fistoulari.
Richmond BA 42003 mono
Tchaikowsky: Sleeping Beauty (complete).
Paris Conservatory Orch., Fistoulari.
Richmond BA 42001 mono
Here is more Fistoulnri ballet music, and
two 1""e IiPl' luw-prit-ed specials I cau't conceh·p of. Th e re(,ol(ltn~s, in 1110no. nre reully
sl'lpndld an,l perhaps on ly the luck of a
stereo version put" tb em into tbl' inexpensi \'e (·ategory. I"avoraule economics for tbe
COllHlllUer!
The complete Tchaikowsky hallpts can be
bell\'y !!,lIing in the long pull--they n ren't
shllrt aUli. though key t11Pllles do rpturn
of len. tllp shepr piling up of so many gbortish (I:lllce pieces. plu" those eternal fancy
mnsi('111 perorllti"n" (for the dllncers. of
c"urse-to he plllypd against storm" of clapplnlr untl hrll\'''s) can run yo u quick l, into
slltlety. But ,,'orst of all. with TchaillOwsky,
I_ 11Il~' pprforlllHnl'l' that triPR to push the
wl'lI-knnwn 'l'l'huikowsky wel'ping ancl waUlung too bard. It never should outwardly
AUDIO
•
FEBRUARY, 1961
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S:V·l0930. CHOPIN Etudes
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63
be pus hed in allY of his scores, symphonic
or no. H e tells his own story best in terms
of careful accurate playing as per the writt en score.' But in ballet music, the over-ripe
approach , the semi-hysterical, can be utterly c eadly .
Fistoulari is marvelous here. Everything
wonderfully neat and accu rate, the music
sparklingly alive and expressive yet never
out of the careful scale.
I don' t lmow how a ballet dancer would
feel - abou t these performances- I am not
one. But for top listen ing, this mah, with
both the British_ and the French orchestras,
has the right; tIte 'inusica l way and no doubt
about It for my taste. I'd put these at the
very top of all recordings of t h is music.
Tchaikowsky: Allegro Brillante (Piano
.. Concerto No.3). Glasounov: Pas de Dix.
Glinka : Pas de Trois. New Yo rk City Bal·
let Orch ., Irving .
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64
I played this disc a few days after I'd
made a pleasing visit to the City Center itself (dilferent music) and I was astonished
. to find how familiar was the sound of these
ballet sco res. The Ci.ty Center prodnctions
have a very positive, though perhaps indefinable, aura and quali t y all of their own,
compounded of excellences and bumbllngs.
of sheer verve and occasional over-brashness.
Oddly, these -over-all qualities come through
in the music Itself, minus ballet.
The only notable dilference I noticed here
was the sort YOU'll always mysteriously
find in reco rdin gs, with their very special
methods of getting put together: In the flesh
I found this orchestra excellent In the
strings, but (that evening anyhow) very
wobbly in the brass and woodwinds . .Here,
the r oles are changed and the brass IS excellent but the strings aren't very reliable in
detail . Could be merely the large dilference
in audible distance. I was well back in a
balcony, whereas here I am placed, via the
mikes, only a few yards away.
I rving is a splendidly practical, workma nlike and mu sical ballet conductor even .if
he is not always able to make his somewhat
frenetic players sound like the Philadelphia
Orchestra. .A. good diSC, this.
The cover titles are those of the ballets ;
the mus ic is the seldom-heard fragmentary
Tchaikowsky Thi,-d Pinno Ooncer:to, selections from "Raymo nda" of Glazounov, and
"Russian and Ludmilla" of Glinka, the whole
disc Russian.
is Sound"
Rita Ford Music Boxes in Hi Fi.
Dot DLP 32 36
Thi s collection makes a nice addition to
those I've had previously from the Bornand
company and others. The variety is quite
large and a few of these machines produce
rema:-kably invol ved 'a nd interesting musical
arra'n gemen ts of overtiit'es a nd the like. No
wheezing a nd out-of-tune sound here--Miss
Ford keeps 'em in apPle pie order. Featured
are the orchestrion, a beer garden (yep).
an ariosa, a ma nopan, assorted Swiss clock
boxes and an 18th century orga n from England.
A Prog rC;lm of Russian Song. Jaroff
Women 's Chorus, Serge Jaroff.
Decca DL 710019 stereo
The diminutive conductor of the Don Cossacks (he's a lways called t hat) is now almost too plump for h is cossack uniform after
some forty-odd years of plumping for Russian
mus ic outside of Russia, but he still h as
the same way with his voices--even these
la dies, a new angle to his characteristic work.
They're good, very good.
.
What I keep wondering, now more t h an
e,-er, is how do the Cossacks (and these D!lW
ladies) keep perpetuating themselves from
non-Soviet sou rces ? Are they really Russian?
They sound it. Do they never get any older?
They don't seem to. How recent is their
AUDIO
•
FEBRUARY, 1961
latest contact with the Mother-land? Is the
tradition (including the singing style) kept
alive strictly in exile, without refertilization
from the home country?
By the sound, I'd guess that the various
Jarolf groups still do not reflect the changes
brought about by the Soviet system in all
its cultural complexity-those of us who have
heard numerous recent Russian folI' recordings (have the Cossacks 1) will note the new
harder, more dynamic styles, the higher tension. These exiles (or are they just Americans
and assorted Europeans, trained to sing a la
Russe?) produce a lovely, more leisurely
brand of Russianism. Up to date or t;lO , the
Jaroff singers of both sexes are unfailingly
musical and boast tremendously interesting
and varied vocal prowess. Good stulf.
Latest Issue of
TUNG-SOL TIPS
tells you what you should '/lnow about
MULTIVIBRATOR CIRCUITS
AUDIOCLINIC
(f1'om page 4)
9-spea7cer systems. I have set the level controls according to the method described by
the spea7cer manufacturer-by 'ear. The results are satisfactory to me. However, after
awhile, it seems that maybe a little stronger
treble would sound better. Therefore, I increase the gain on the treble horn. Th en
later, I may find that by mising the level
of the midrange spea7cer I i1nprove the
"presence," and so on.
Although I understand that the actual
sound quality from the spea7cers depends
very much on the room or the environment
in which ' the spea7cers are placed, is there
not some way to determine at what setting
my spea7cers are balanced other than by
using my ea1'? I would not stic7c to this
settvng i f it did not please my ear, however. James J. Allain, Jr ., Par Allen,'
Louisiana.
A. Since the actual balance among th,'
three speakers in a 3-way system depends
upon the room in which the equipment is
housed (as you suggested), it is impossible for the manufacturer to give you
any additional instructions other than those
he provides with his speakers. If you have
an audio oscillator and a calibrated microphone, more accurate control settings can
be found.
Of course, the calibrated microphone
must be placed in the position which the
listener would use' or the resulting readings
will be faulty. The use of a calibrated
microphone may not be f easible for you,
but your ear can be used as a good substitute.
By using the audio oscillator to sweep
the audio range you may well hear whether
the midrange is louder than the woofer,
etc. The best way to accomplish .this result
is to sweep from a point somewhat below
the crossover point to one which is somewhat above this point. An octave on each
side of the crossover point should be sufficient. This technique can be used for both
the midrange and tweeter crossover points.
This procedure should be followed with
the observer in the position most usually
occupied by the listener or listeners to the
equipment.
JE
AUDIO
•
FEBRUARY, 1961
is a typical multivibrll;tor eirc.uit. ~t's just one of several
which perform many baSIC functlOns m computers and electronic counters and which find wide use as waveform generators. For the serviceman planning to expand his business to
.industrial equipment servicing, a thorough knowledge of these
devices is a "must".
To give you this fundamental grounding in multi vibrators,
Tung-Sol has devoted the latest issue of its monthly series,
Tung-Sol Tip s, to a vigorous, down-to-earth treatment of
these important circuits.
In issue # 13, you'll find a comprehensive, fast-reading analysis of all the multivibrator circuits which you can expect
to find in your industrial work. These include: the bistable
multi, the cathode coupled binary, monostable, astable and
high sp,eed J,nultivibrators.
The operation and application of each is carefully defined.
Many circuit diagrams are included to rouna out your
understanding.
There's more! The author has also included a special section that gives you maintenance and servicing clues that you
can put to practical use immediately.
Don't miss out on this really important issue of Tung-Sol
Tips. It's yours merely for the asking. Just drop into your
Tung-Sol distri~,utor. Or write direct.l y. Tung-Sol Electric
Inc., ,Newark 4, N. J.
ERE
H
®TUNG-SOr
SALES OFFICES: ATLANTA, GA.; COLUMBUS, OHIO ; CULVER CITY, CALIF.; DALLAS, TEXASj DENVER,
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65
fPijPUlAR '
MORE
Continental Encores/Waltz
Encores-Mantovani (Twin. Pak). london/lCK, LPK-70024
Adventures in ParadiseAlfred Apaka, RoY 'Snieck,
Terortua & His Tahitians, The
Islanders. ABC Par-amount/
ATC-816
Tonight ... Town Hall Concert
-Roger·Williams (Twirl'
Pakl. KaoD / KT-45009
The Roaring 20'5l Grand Award/GASD-229
Ten Greatest Pop 'Piano
Concertos/ Renowned Pop
Concertos- George Greeley:
Orchestra (Twin-Pak) . .
.Warner Srothers/ PST,2401
CLASSICAL ,
Stravinsky: The Fire Bird
(Complete Saflet)/ Song of
the 'Nightingale, Pulc ine lla
Suit~Ernest Ansermet, .
l'Orc.hestre de la Suisse
, Romande (Twi n-Pak).
london/ lCK, lPK-80042
MORE
OPERA.'
Ponchielli: la Gioconda
(Complete)-Del Monaco,
Cerquetti (2 reefs).
lOQdon/lOR-90004
leoncavallo: Pagliacci
(Complete)-Del Monaco,
Tucci. lon~on/lOH-90021
MORE
DANCE MUSIC
SOUND SENSATIONS
with Ros-Edmundo Ros and
His Orchestra (Twin-Pakl.
London/ LCK, LPK-70038
Spectacular Harps-Robert
Maxwell. MGM/STC-3836
The Sound of Top Brass, Vol
2-Peter London Orchestra.
Medallion/MST-47008
Perfe~t for D~ncing/Dancing
'1 WanUo Be Happy Cha
Cha's-Enoch Light.
Grand Award/GA~D-222
MORE
and
HAROLD LAWRENCE'"
Portrait of a Rehearsal
David Randolph, would
have been justified in experiencing a
degree of apprehension on the morning
December 10, 1960. The Masterwork Chorus
(Morristown, New Jersey), which he had
co-founded in 1955, was scheduled to mnke
its Carnegie Hall deuut that evening under
his direction in Bal'h's "Christmas Oratorio." A three-hour session had been called
for 9: 30 a .m. at Carnegie Hall for the
first and only full-scale rehearsal with all
the musical forces involved in the performance. It was imperative that Mr.
Randolph operate with unusual speed and
efficiency. The allotted rehearsal time did
not permit a run-through of the complete
oratorio which, counting pauses, is itself
more thau three hours loug. To cover the
gronnd, the conductor planned to omit certain repeats and to move ahead to the
ne:A1; movement whenever things appeared
und er control.
In previous rehearsals, Mr. Randolph
had worked with the chorns for several
months, imprinting on the minds of its
members detailed instructions regarding
tempo, diction, phrasing,- accents, and tone
quality j and, during the week before the
concert, he had held sertional rehellJ'Rals
with the orchestra, soloists, and chorus.
Now the component parts were meticulously
HE CONDUC'l' OR,
T
* 2 6 W. 9th St., New York 11, N . Y.
prepared, but the fact remained that they
had not yet been assembled. This was not
due to an oversight. The budget of thiB
non-profit choral organization was already
strained by the expenses of a New York
conrert- rental of the hall; printing of
tickets, programs, and miscellaneous literature j payment of nshers and stagehands;
and costs of transporting and acco=o·
dating in New York the out-of-state choral
si ngers. Finances simply ruled out more
than one "dress" rehearsal.
Some two hundred and seventy performers, therefore, were gathering together
for the first time. Critical acljustments
would have to be made to each other and
to the aeoustical properties of the hall.
The conductor could only guess at the potential so urces of trouble: ensemble problems would be the easiest to spot and
correct; more tricky were the factors of
balance and dynamics upon which the
hall's sonic ch aracter would have so great
an effect. As the stage began to fill up
before him, Mr. Randolph must have felt
like a space scientist wat~ hing a missile
on its launC'hing pad at firing time.
Busy counting the noses of arriving performers, the cond uctor found that his own
nose had become the object of an earlybird photographer, who had forused an
exposure meter on it to obtain a light read·
ing. Other amateur photographers had also
A Journey Into Stereo.
london/lPM-70000
Pyramid/ NO Sun in Ven iceModern Jazz Quartet (TwinPak). Atiantic /AlP-l,~04
les McCann Plays the Truth/
• Les McCann Plays the Shouj .
(Twin-Pak). World Pacific/
WPTC-1016
MORE
MUSIC IS ON
4-TRACK
STEREO TAPE
For Free Catalog, write: 1024 Kifer Road, Sunnyvale, California - UNITED STEREO TAPES
66
Yt'T
(Photo by Harold Lawrence )
Fig. 1. David Randolph conducting the "Christmas Oratorio."
AUDIO
•
FEBRUARY, 1961
infiltrated into the rehearsal, their tripod
cases passing for bassoons. One had set up
a large camera in a first-tier box. another
had squeezed into the woodwind section of
the orchestra to aim his Hasselblad up
towards the podium, and a member of the
chorus (honor) carried a 35-mm camera
along with his music. By mid-morning,
there were some half dozen cameramen
perched on different vantage points in the
hall. The clicks of shutter releases and tIle
squeeks of film transport mechanisms at
times provided a steel-cricket obbligato to
the musical performance-an appropriate
effect for the movement which opens P a rt
II of the "Christmas Oratorio," the Pastoral Symphony.
The battery of lenses aimed at the
podium might have rattled other conductors, but Mr. Randolph was beyond distraction: There were more urgent matters
at hand. For example: "Where was the
harpsichord ~" "Why hadn't risers been
laid down for the chorus'" "How are we
going to fit the instrumentalists on the
crowded stage ~ " The harpsichord finally
arrived, but not the risers; and the orchestral players were accommodated snugly
on the apron of the stage. The clock in
the wings read 9: 30. Mr. Randolph inspected his musical forces. Noticing an unevenness in the ranks of sopranos and
altos, he called out, "Will the pregnant
women please sit near the door f" Concert
hall esthe;ics disposed of, he dispatched
Shirley May, the president of the chorus,
and three other musicians into the hall to
function as aural monitors. This was a
necessary precaution. Conductors know th at
the podium can be a deceptive listening
point from which to evaluate balance.
dynamics, and even ensemble in an unfamiliar auditorium. And this was Mr.
Randolph's first conducting experience in
Carnegie Hall.
The opening of the "Christmas Oratorio," J auchzet, fj'ohloc1cet! with its joyful punctuation of trumpets and timpani,
got the rehearsal off to a vigorous start.
At the conclusion of the movement, th e
conductor asked the opinion of the monitors. "Diction, David. We can't hear a
word back here, it's all a wash of sound."
Mr. Randolph replied, "You realize, of
course, Shirley, that the chorus is not on
risers. Nevertheless, we'll try it ngain. (To
the chorus) You all . heard that. While
we're on the subject, I should like to add
that there's not a rolled 'R' in the bunch.
And smile, darn you, this is a happ y
work!" Articulation and spirit improved
noticeably in the second attempt, hut th e
ensemble broke down in the sixteenth-note
passages. The comlue-tor offered a practical
solution: "Stay with me, don't go by what
your neighbors are doing."
As the last notes of the choral "Wie soli
ich dich empfangen" melted into the quiet
hall, Mrs. May, unmoved by the ' performance, uttered the startling suggestion,
"Shoot the bass!" The bass line, it seems,
had upset the musical balance by emerging
above the other voices. In another choral,
Mr. Randolph checked a bad case of sagging pitch with the admonishment, "Think
high."
The first and only purely orchestral
movement in the work, the Pastoral Sym(Continued on page 78)
AUDIO
•
FEBRUARY, 1961
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67
bancl. The next logical step could only be an
extension of the theme, and be takes his men
rigbt up to the edge of tbe mytbical creekb~
and sits them down. Like so many other Jazz
artists, arrangers often do best when not
creating to order.
Holman's scoring is generally lighter a nd
more swinging tban on a previous band date
for t he Andex label a season or so ago, and
the change in sentiment is expressed on his
li "ely QlIickstep. His other original is a peace
offf' I'in g fo r Capitol engin eers, and th e plpe is
pa ssed ba ck and forth Indian fashion by brass
and reed sections on Stel'eoso. The control
)'oom returns the compliment and favors his
first ba nd offering for the company with outsra nding sound. Holman's treatment of standa rds assures a return visit, and be solos longin "ly on In A Senti1nental Moo(l . Conte
C~do1i,. Bill Perkins, Joe Maini, Jimmy
Rowles, and Mel Lewis are among the California j a zz specialists who help out on such
tunes as Shadl'ack, The Moon I s Blue, and
Jnne Is B"s·t ing Out All Ovel·.
CHARLES A. ROBERTSON'::
STEREO
The Modern Jazz Quartet: Third Stream
Music
Atlantic SD 1345
Jackie Gleason: Lazy Lively Love
CapitolSW1439
New jazz categ!lries are constantly being
thought up to soothe persons who like to claim
they never listen to jazz, and two of the most
recent succeed in a voiding any u se of the
word. Efforts to combine jazz and classical
forms once were described adequately as
chamber jazz or symphonic jazz, depending
upon the number of players and decibels involved, but both terms now are in disfavor.
Third-stream music, a substitute phrase which
Gunther Schuller coined and then introduced
to the public In billing a concert of his works
laat May, is the latest vogue. Jazz journalists
Immediately saw magic in the words and are
reporting each development with all the avidity of fashion writers at a Dior opening. As
the tag also is affixed to the Modern J azz
Quartet's new album of works by Schuller,
Jimmy Giuffre and John Lewis, with the promise of more to come, it should remain in style
until next season at least.
Once the album title lures listeners with
concealed leanings toward jazz, all three composers are careful not to displease anyone.
Of course, a name like the Third Stream Quartet might mollify some purchasers further,
but very little in the way of jazz 'Is asked •.of
the group and it sounds even more subd·\!.e d
than u sual. Mood music devotees in particulat
will find it restful when the Jimmy Giuffre
T bree joins in on two pastoral settings, both
devoid of disturbing animal life. Should the
record fall Into hands of the more violent detractors of the Quartet's previous work, they
will be unable to apply their favorite epithet
"pallbearers of jazz," as the corpse never arrives this time.
The longest and most interesting work is
Oonversation, Schuller'S lone contribution,
which engages the Quartet In a clever dialogue
with the visiting Beaux Arts QUartet. The
classical contingent is given the dominant role
for once, and supplies the excitement usually
asked of jazz players in a series of dramatic
Interludes that resemble the climaXes of Bartok's string quartets. The two opposing forces
never get together for a joint statement, however, and the jazz group has the limited task
of resolving tensions already Introduced. The
Modern Jazz Quartet, which has resisted efforts of j azz copyists to ascend to the same
pinnacle, is reduced In this context to the
emotional level of Martin Denny's group of
South Sea I slanders. The exotic bird cries are
absent, but the presence of Ornette Coleman
on another of Schuller's compositions should
correct that omission in the n ear future.
The packaging is just fashionable enough
for people too pretentious to keep jazz about
the house under its proper name, with a cover
abstraction in Grand Rapids modern and imported liner notes purchased from an English
critic. The stereo engineering by Earle Brown
and Franl, Abbey is faultless and comes from
Capitol studios.
* 732 The Parkway, Mamaroneck, N. Y.
68
Jacki e Gl enso n 's m ood n1hutn s rack up en-
viabl e sa les figu res, ye t in t roduce such jazz
wOl'thies as Bobby Hackett and Lawrence
B"own to people who m ight n ot hear them
otherwi Re. The meetings are usually carefUlly
arra nged, with the soloists surrounded only by
circumspect- strings. If the truth were known,
the rotund comedian long ago launched a
sch eme to gradually increase tbe jazz content
of his offerings. One of his choice customs is
to engage a good group headed by Max Kaminsky, an unreconstructed Chicago-style trumpeter, for a little travelling music to enliven
his arrivals and departures on road trips. A
jovial host, he hates to think anyone is missing the fun.
Ju st such a group goes to work on his latest
LP, a nd it stretches the mood category to the
breaking point. Instead of a lone soloist in the
foreground, tbe massed strings compete with
the full stereo spread of an uninhibited nonet.
Something bas to give witb a front line ()f
Ruby Braff, Buck Clayton, and Yank Lawson
on trumpet, Buster Bailey and Andy Fitzgerald on clarinet, and Lawrence Brown on
trombone. Gleason shows that he a lso can
turn the tension and relaxa tion trick, first
programming such lazy melodies as Speak
Low, Lover Man, and It Had To Be Yo". Then
to leave tbe customers happy are such lively
alternates as Exactly Liloe Yo", Too Close For
Comfort, and BI·eez·in' A long With The BI-eeze.
The rhythm team includes Claude Hopkins,
Al Caiola, a nd Milt Hinton, while the arrangements a re credited to George Williams.
As Gleason proceeded witb the plan to bring
jazz to the stage where it equalled or overbala nced the mood .:porti'Ons on his LP's, he
realized the end product would need a new
label. After llUlch scholarly research, he decided the rigbt mixture would be called fourthstream music. To arrive at this title, be was
forced to look outside musical fields and investigate thoroughly the .secret art of blending. It refers to t he four main varieties of
Scotcb, pot-st ill whiskies which Highl ander s
combine to produce the final harmonious
article.
Gleason's present concoction seems about
right, and the next one may suit his standards of perfection well enougb to wear the new
title in public for tbe first time. Wben that
happens, other entrepreneurs wbo hide j azz in
mood settings are expected to reveal tbeir part
in the plot. Among hi s fellow conspirators are
Steve Allen, Arthur Godfrey, Michel Legrand,
Paul Weston and Henri Rene_ Just so long as
the strings hold up, a label which carries so
many pleasant connotations should endure.
Bill Holman's Great Big Band
Capitol ST1464
Between playing tenor sax on other leader's
dates and arranging chores for various bands,
Bill Holman found time to assemble a big
studio band and work out some of his writing
ideas in his own way. Perhaps tbe best vindication of all the effort is found on Spinuet, a
superb blues waltz that descends directly from
Duke Ellington's scoring of the film "Anatomy
of a Murder." Holman arranged the theme
first as a background for Peggy Lee's lyri cs to
I'm Gonna Go Fishi n', t hen as a buoyant instrumental for t he Gerry Mulligan concert
"
Tex Beneke: The Alamo
RCA Camden CAS655
Dutch Swing College Band: Twelve Jazz
Classics
Perfect PS14038
Besides presenting a good stereo spread,
t h ese low-priced albums are durable and handy
to bave about the house for the next dancing
party. In fact, Tex Beneke's selections from
the Dimitri Tiomkin score probably will be
played long after tbe film sound-track LP Is
forgotten. Arranger Ray Martin gives the more
fetching themes considerable space and a
rhythmic beat, with only a slight nod In the
direction of purely descriptive interludes. The
lad from Texas feels rigbt at home on the
vocals, still has tbe old Glenn Miller touch as
leader, and plays free-and-easy tenor sax.
The Hollanders take up a stand midway
between srtaight New Orleans style and the
h appy traditionalist sounds of their English
cou sins. They play the regular dixieland book,
take a flyer at Ellington on Black And Tan
Fantasy, a nd offer one 01' two originals, nota-·
bly Mal-ch Of The Indi ans. Tbe clarinetist,
possibly the best to be hea rd t h e otber side
of Britisher Monty Sunshine, solos long and
eloqu ently. Tuba and banjo are a rrayed In
stereo to steady a ny faltering steps.
Stan Kenton: Live At The Las Vegas Tropicana
Capitol ST1460
Only the rarefied atmosphere of Las Vegas
could cause Stan Kenton to unbend enough to
indulge in a little dixieland tomfoolery on a
tune called Yo" And I And George, whicb allows the trombone section to run riot. And
tbe paying customers are entertained further
as Billy Root wheels a rakish baritone sax
througb Gene Roland's whimsical Puck's
BI·u es. Some degree of order is restored before
long, but the band continues to swing unrestrainedly and does full justice to TIt-a:edo
Juncti on, Sentimental Riff, and Ben.ie's Tune:
Soloists Lennie Niehaus, Jack Sheldon, and
Richie Kamuca find their luck running high
and ride it to the limit. Capitol engineers turn
in anotber fine on-location j ob, and tbe leader,
in stereo, seems to hold the Tropicana audience right in the palm of hi s ha nd.
J. J. Johnson: Trombone And Voices
Columbia CS8347
Geo rge Shearing: The Shearing Touch
Capitol ST1472
If J ack Teagarden and George Shearing can
cash in on mood a lbums, who will deny J. J.
Johnson the right to reap the profits from one
of his own? Frankly, ' tbe change of pace and
style on this LP gives the top-ranking jazz
trombonist a chance to disclose aspects of his
playing that are usually hidden. Cast as the
leading voice in a wordless choir wbich arranger Frank DeVol pipes in from various
points on the stereo stage, he adopts a bigger,
warmer tone and drifts effortlessly through
Bernard Hermann's J ennie's Song, Motherles8
Child, and In A SenUmental Mood. One or
two technical displays are set off to keep in
trim, but for once Johnson's work Is characterized by Hoagy Carmichael'S Lazy Bone8.
George Shearing's supporting cboi r on this
occas ion is composed of just strings, arranged
AUDIO
•
FEBRUARY, 1961
... A SPECIALLY COMMISSIONED
LIMITED EDITION
RECORDING ...
"The Orchestra .•.
The Instruments"
No. LS661
Without a doubt, the mos~
ambitio us, musically sound,
entertaining and informative
privately commissioned stereo
recording to date. SuperbJy
original in concept, extraordinary in scope, it shows how
each instrument (and instrumental choir) emanates from
the orchestra in the correct
spatial relation to all other instruments. Supervised by Dr.
Kurt List, winner of the Grand
Prix du Disque, renowned composer, critic and Musical Director
of Westminster; recorded by the
Vienna State Opera Orchestra in the
acoustically brilliant Mozartsaal concert hall; Franz Bauer-Theussl conducts,
with first desk soloists: Program material
is a cohesive musical entity with works of
Cimarosa, Debussy, Dittersdorf, Handel,
Haydn, Lalo, Mozart, Rachmaninoff, Respighi,
Rimski-Korsakov, Tchaikovsky, Wagner, and
Weber represented. No one can buy this record- ,
and there is no record like it.
A GIFT TO YOU ...
when you buy any of the following ,
Shure Stereo products:
• I
\
You will receive the Westminster/Shure recording
at no charge with the purchase of a Shure Professional Cartridge (Model M3D $45.00; Model
M3D with N21D stylus $47.25), Custom Cartridge
(Model M7D $24.00; Model M7D with N21D
stylus $36.75), Studio Integrated Tone ·Arm and '
Cartridge (Model M212, M216 $89.50) or Professional Tone Arm (Model M232 $29.95, Model
M236 $31.95). All prices audiophile net. '
Music lover's record
. selection booklet ...
tells how to preserve
record fidelity, explains
hi-fi stereo.
Send 25¢ to:
Shure Brothers, Inc.
222 H a rtrey A ve.
Evanston, Ill.
D~pt. LLL
AUQIO
•
FEBRUARY, .lQ61
Offer limited. Send "Customer Comment Card"
(enclosed with product) and sales slip to Shure. See
your local high fidelity dealer. (Listed in Yellow Pages
under "High Fidelity," "Music systems-home".)
in number~ ample enough to assure a plump
tltereo .nllnd by an eqllally large-III'opo"tiuned
nilly ~Ia~', _\ dllzen themes assol"int('d WI! h
other k('~'h"'!rd notables rpceive the ~hearing
tOllch. Inrlll<ling Claude Thornhill'. Sno.vjall,
Erldip
1I1'\'\\'ollf)"s
Garner'"
;lfiH ty.
Oanarlifln
and
Andre
SunRet.
Previn's
ErroU
Li,ke
Young, Playful salutes to tbe original versions
in pa"RiJlI! IlI!Ilin prove the pianist to be a
maRter s'yllst. Perhaps out of respect fill' his
fellows. ~hel... ing is pictured at the piano OIl
the cover. ,'epillcing the calendar art on his
recenf 1110011 aIhull1s.
Lambert, Hendricks And Ross Sing Elling.
ton
Columbia CS8310
The Double Six of Paris Capitol STl 0259
Aft<'r setting :l mark on COUllt Basic MllndardR fo,'
jazz vocal g"oups to shollt at,
Lamhprr, I\ pn'II'icks and Hoss pick "ut a no'able shellf "I' llllke Ellington COlli positions as
tarl1ets IIn.1 ,'u('k up another high score, Ap-
"tI,,,,,
pe~lrin:!
in :-:tPI'PfI
.in~t
fiR they do at c'onC"prt
and cluh pprfo'lIlal1ces, they apply a spedal
bnln.l t)t" Vlu':11 It-'~el'llemnin to :-::l1ch fH\'oriles
as Curlin",. 7'1, ;11.(/,. Ai.n ' t 'W hat Thr/J Csp.d
To Re. 1111<1 .1fi,", ' (/ht Indigo, They I1P,'e,' resort to thp plp.,tl'llnic crutches of o,'enlubbing
or chan lH'1 swil('hinp: to simu lat e fu ll ol"l'lIpstral textllres or original solos, OIl tbe th .. ory
that most audiences know the arrangements
w ell enough to compensate for any lIIi~sing
pa,'ts, they depend for ~upport sol e l~· IIpon the
Ike I~anc~ trio. tbeir regular R..ccotllJlan)"ing
group, As befO/'e. they tHe 1II0st COlllfOl'tllble
on the blues 0" at dazzling fast tPlIIPOS,
Bend "iel<s seem~ ill at ense on the bllllad ic
AU Too SOOIl. bllt Miss Hoss restores the balance witb a lovely so lo on In A jJ/pllow Tone,
Tbe Double ~(x is almost as milch a product
of electronic t /'Ic'k€,,'y as it is th., brain child
of Mimi l'e rrin , who fomled tbe grollp on hea ring its Americ'lIn <:ollnteqJHI't sing Basie In
1950, The six ,' oires dllh in the hl'llNs and reed
section \Vo,'\<. a.fter a('tual instrulllPnts are
used to re('ord the rh ythm parts, amI ,'eturn".
aga in to iml'me ,'ariulls SH I!) flights, Stereo
ties the whole packal-:e togethe,' in realistic
band uimt'nsions. n('~t'lC"s pro\' i(ling non-'1
French lyrics, )[iss PelTin sings in deep tones
th a t cOlllplenwnt the spnsutiona( high notes of
Cbristianne L~gl'Hn(1. the only n,her fplIIinine
member of til<' tellln, The ~iste,' of ~Ii('bel
Legrand, !=;:he oftPIl a~s:i:..:t" on the vcu'a l bat:l~­
grounds of h;s 11100.1 aibullls and al"" ghosted
nrigi tte na,'dot'~ scat-"ingin~ in the film "La
Pal'ixienne, " Accol'ding to the liner notes. no
r ecording tricks are ilH'ul\'ed in her ability to
Dlatch th e upper reach es of
a::;cents. R ecl'eations of Quin cy
Sound Effects, Volume 1
Audio Fidelity DFS7006
Fifty different sound effects are compiled
on this tlrst volume. amI where the toral will
stanel >1t the conclu,ion of the projected series
is anybo<ly'~ gues~, Among the interesting
coml"lI'isons afforded is one betwe€'n a Hoyal
typew"ite,' and an IJ:~[ electric typewriter,
so pe,'halJ" the intention is to work UI' to the
though t processes of II n In)! ele('tronlc computOl'_ To get the show on the ,'oad, rPlurn
visits are paiel to many fm'ortie sllbJec'ts h€'ard
on pl'e\' ious nlhulHx of a :-oilllilar nature,
wh€'th€'r III'oelU('eel by Audio Fideilty or other
labels, The eliesel anel stealll enl!ines. j et airplnnps. l'lH' in~ ('nr~. thunder null ~lIrf lifE' all
here. a(on~ with a nUlIlber of unexpecteel ~ur­
Iwises, Just two examples are wa ' er drllining
from .. sink a s though the plulIlber was on
'Yma
~ull1ac ' s
hnnrl t o IlPlp it alon:!. and an llttklluwn pxpert
.10111'8
nrl'nnJ!e-
ringing all the changes on a pin bllll nllichine,
Allhough tbe volume is listed in the com-
ments, introdu ced during bis recent European
This is one of the two speakers in
the KLH Model Eight FM Receiving System.
Its precisely controlled motion over a great distance
helps to account for its remarkable performance.
We hope there is a place in your life
for a KLH Model Eight.
70
band tour, comprise the bill of fare which
lists jJf eet B enny Bailey, For Lena And
Lennie, and Horace Silver's Doodlin.' College
students should find something in the lyrics
to confound French professo,'s. and Hendricks
may feel impelled to start work on a Quincy
Jones set,
KLH RESEARCH AND DEVELOPMENT CORPORATIOn
:10 CROSS STREET. CAMBRIDGE 39. MASSAC,HUSETl'S
Descriptive literature, with the name of
your nearest franchi sed J( LH dealer,
is available on reqllest,
AUDIO
•
FEBRUARY, 1961
The touch of Murray G. Crosby has created
a truly remarkab le stereo receiver . .. the
R80. Like all other receivers, it combines
AM and FM tuners on the same chassis with
stereo preamp and dual power amps, but
here the departure begins.
Examinefirst, power. The R80 boasts 80dis·
tortion·free watts, 40 per channel, enough
to drive any speaker system made. To control this magnificent component is sheer
.simplicity. Wherever possible ganged,
push-pull knobs are utilized. Source selection is achieved through push-buttons. Visually, the R80 is exceptionally pleasing and
compact for custom installations. The handsome face is brightened by a concurved,
illuminated tuner dial, variable mono/
stereo blend lights and an ex clusive two-channel indicator
for tuning and program level.
Exhibiting versatility, the unit
features front panel controlled
speaker / headset selector,
tap~ monitor facility, and
spe6ial volume control for 3rd speaker stereo installations. '
With an eye to the -future,
Crosby has eliminated the"
chance of obsolescence by including a Multiplex Dimension control and powering
facilities for a non-powered accessory Multiplex Adapter.
~. .
Unique features, excitingly used , make the
R80 the remarkable receiver that it is. And
though the performance stands above all
others, the price doesn't . . just a valuesetting $375 .
• 'r.w.~
l-
1
#'
-
i
.,...-
~-..u.-_lot
~~
.
CRO'5BY R80 RECEIVER. 161!z" W. x 5¥s" H. x 14Y," D. OPTIONAL WOOD OR METAL CABINET AVAILABLE .
stereo Crosby
BY
AUDIO- ' FEBRUAR~ : '191)1
Crosby Electronics, Inc•• 135 Eileen Way· Syosset, L.I . , N. Y.
Manufacturers and designers of stereophonic components,
speakers and the Crosby Compatible Stereo FM Multiplex System.
71
pany's Super Stereo series, the only doctoring
administered is a microscopic examination of
some sounds that are ordinarily heard in
noisy su rroundings. A door creaks at a ghostly
touch, while a n air hammer and compressor
blot out passing street traffic. Only the operators, live or ethereal, would stand as close
as the microphones are placed. If anyone
wants to know pow it feels to go through a
pane of glass, the experience is right here
waiting and nothing softens tbe blow. In these
cases, the avowed purpose is to present effects
in the purest state possible, before they become diluted or diffuse. Crowd noises, zoo animals, and the blast of an ocean liner are
recorded at a more normal distance. Considerable patience and know-how is devoted to making each come alive with stunning realism.
The listener who wants a succession of
spectacular effects in rapid order will find the
grooves between bands locl,ed, and the pickup
must be moved each time. A boon for home
tape enthusiasts, this safeguard frees both
hands for use in manipulating a tape machine ·
and introduces no unwanted noises as the
locking grooves are silent. The more experienced should have a fine time adding reverberation to some episodes, or altering the perspective on others, depending upon the context in which the material is to be employed.
Science fiction fans are hereby alerted that the
next chapter deals with Outer Space, but the
end is not yet in sight.
Jo Stafford: Jo Plus Ja zz
Columbia CS8361
Kay Starr: Ja zz Sing e r
Ca pitol ST1 4 38
At a time when few female jazz singers are
worthy of the name, tbe arrival of two vocalists from the popular field is a welcome event.
It becomes doubly so when the visitors call on
the respective alTanging and conducting talents of Johnny ~Iand el or Van Alexander, who
supply rugged t e t s of a singer's ability. J 0
Stafford is able enough and knows as much
abou t the art a s a nyone else. If tbe accompanying g l·oup s li g htly overshadows ber,
neither she nor the listener has reason for
complaint. She aims at nothing less than the
top, drawing responses of similar loftiness
from tbe likes of Ray Nance, J ohnny Hodges,
Ben Webster, and Mel Lewis. The Ellingtonians do well by D ay D,·ea1ll, with John
Latouche lyrics, and other t u nes associated
with their employer, while the singer recalls
her Dorsey days on For You, What Oan 1 Say
After 1 Say I'lIl Sorry, and D,·earn Of You.
Another Dorsey alnmnus, Frank Sinatra,
might try Mandel's brand of swing for a
change.
Kay Starr nearly qualifies as a jazz singer
wbatever tbe context, but her break with the
popular idiom sounds a little tentative, almost
as tbough Capitol wanted to look at the sales
sheets before allowing her to go further.
Alexander gives her a chance to try her luck
on a variety of settings, spotting an electric
organ or singing ensemble on some, and using
a big swinging band on others. A good indication of what she could accomplish with an
Ellington contingent , or at a reunion with
Charlie Barnet for that matter, occurs on
H1£1II1IIin' To Myself. Her brasb style and full,
rich tones are eminently suited to My Honey's
Lovin' Arms, and Hard Hem·ted Hannah.
Always a pleasure to hear, her big voice is
one that remains undiminished in stereo.
Belafonte Returns To Carnegie Hall
RCA V ictor LS06007
Now that Carnegie Hall is safe from wouldbe demolishers, Harry Belafonte's concerts
there can be looked forward to as an annual
event. The one-the-spot recording of his second
appearance is as fully rewarding as its predecessor. especially since the. singer welcomes
two of his proteges. Odetta performs Water
Boy, and I've Been D"iving On Bald MounttUn,
as well as being a foil for Belafonte's quips
on tbe delightful Hole I n The Bucket. He in
turn acts as a partner for Mariam Makeba,
the Soutb African girl be encouraged to come
to thi s country, on The Glick Song. Belafonte
also sings in her native Xosa dialect, but only
Miss Malieba can say how well be bas mas·'tered the tongue-twisting language. T be Cbad
Mitcbell Trio does its specialty, The · Ballad
Of Sig1ll1lluL Freud.
All of the Belafonte numbers are new to
stereo, althougb two were recorded before.
As was the case wi th the first concert album,
interest centers on his fine sense of timing
and ability to react to an audience. Wben tbe
Belafonte Folk Singers join in at Bob De
Cormiel·'s direction, the stage fills with sound
and movement. Bob Simpson, wbo also engineered last year's concert, sees that none of
it is lost on the stereo version.
MONO
Blind Gary Davis: Ha rl em Street Singe r
Prestige / Bluesville 1015
Although Blind Gary Davis turned from the
blues when ordained as a minister in 1933, he
still qualifies in the Bluesville category due to
a tendency to practice youthful foll\lls wbile
he preaches. A blues timbre creeps Into his
voice even du ring a song as joyous and cheerful as Lo.·d, 1 Feel Just Like Goin' On, and his
. sermons follow country blues phraSing rather
than the printed pages of hymnals. After a
text is stated, Davis frequently omits words
and allows his guitar to do the talking for him
~n the sty!~ lieveloped by earlier religious and
blues singers: Davis can depend upon this
companion of many' a street corner gathering
to Sp~(. in clear tQl1es of spiritual affirmation,
1\. teaffu1Jb\u,e~ throb, or the happy shout of an
old-tune ' camp meeting. It requires no electro!p'C amplificatioll, and the revival flame
bu rns ·brigh t whell the two declaim together
on Let U~ Get Together Right Down Here.
Big ~Bill· Broonzy used to draw the· line be.' tweell gospel music and blues Singing as
shafPly for reasons of style as Mabalia Jack.. §on do~s .toda! ,on:. r!lligious grounds. Every
, ~e~l!e~!alJle ,gO~Il~~'.~I,{lger: sbould know a little
" abo'Ut.;!', fttbe,. Devll'S:·;,musrc," however, If only
to mount a better offense against the ancient
enemy. So when Davis sounds like Broonzy at
t imes, .it just means the Devil is going to be
fought ;that much harder. Davis tells of his
own struggles aRd conversion on Great
Ohanges-Since 1 Been BOI·n. If Broonzy were
still alive to witness some recent mock weddings between gospel · and blues, he might
72
AUDle·-·.
FEBRUARY, 1961
adopt a pseudonym and preside at a few legitimate ones himself.
After first ,'ecording more than twenty-five
years ago on the old Perfect label, Davis next
appeared on two early LP's, but always missed
one of the recurring waves of interest in
country blues, Only a few collectors had the
foresight to acquire copies before they vanished from the lists. Never one to worry about
worldly success, Davis continues to ply his
trade, happy in the knowledge that police
seldom bother a street minstrel who sticks to
religion. Year s spent in the open have made
his voice rough and leathery, yet it overlJows
with compassion and seems to bear a personnal message fo r each member of his small
circle of listeners. He takes his song-sermons
into Harlem storefront churches on occaSion,
but lofty pul pits and large congregations
would be unsuited to his homely parables.
Davis marches a long in the tradition of
Blind Willie Johnson, wh o recorded in Dallas
for Columhia in 1927, and revives the legendary Texas singer's interpretation of the Samson and DeUlah story, along with h is Twe lve
Gates To TIw City. Johnson's versions filled a
need during the depres~ion and were among
the few recordings to sell widely, so perhaps
their return to circulation in these days of
"The Bomh" is appropriate. Producer Ken
Goldstein lind engineer Rudy Van Gelder also
contrlhute to un admirable LP.
-------->
'--
--
SEPARATE HEADS
Bunny Berigan And His Boys
Epic LA 16006
Glenn Miller and His Orchest ra
Epic LA 16002
help make the 3 speed -4 tr.ack
Jazz researchers often find the most revealing period in a player's career occurs sho rtly
before the heavy hand of public approval rests
on his shoulders, and these co\lpctions of h istorical reissues cover just that interval in the
lives of two renowned swing-era leaders.
Bu nny Berigan, in the opinion of many, did
his best work before the burden of maintaining a big band wore him down. Certainly few
trumpets have sounded more vital and pure
than Berigan's horn does on the lyric first
version of I Can't Get Started, and other numbers recorded with small pick-up groups. His
ballad'style is beautifully relaxed, making it a
joy to revisit su ch old tunes as A. Melody In
'['he Sky, and I Neat'ly Let Love Go Slipping
Through My Fingers. And the list of Boys who
were glad to be asked to the sessions includes
Jack Teagarden, Artie Shaw, Bud Freeman,
Dave Tough. and Cozy Cole.
Glenn Miller t eamed Berigan with Ch a rlie
Spival( when shaping his own orchestra, and
they went into the studio on April 25, 1935
to appear t ogether on its first date. In fact.
one of Miller's earliest compositions, Solo Hop,
turns up on both LP's. Two sessions held two
years later show Miller on the threshold of
the formula that carried the band t o the top,
while Berigan struggled elsewhere with the
problems of keeping an organization together
on the road. Smith Ballew's vocals are ancient
enough to hold a certain charm, and Miller
always played for dancers.
R
fandbero
A clanging trolley bell signals the start of
the glorious sound effects which set the two
previous , LP's in this series apart from the
ordinary children 's release. Two Los Angeles
bachelors, J im Copp a nd 'Ed Brown, spend the
better part of a year on each, creating a special little world "for small fry and sophisticated adults" to share together. Copp is responsible for the songs and stories, while
Brown designs the distinctive covers and joins
his partner in playing numerous roles. The
wonderful people and animals t hat inhabit
Thimble Corner make it a funny place, and
fortunate listeners will meet a talking ducl{,
a turkey dressed in satin, Anderson cat, and
the dog t hat went to Yale. 'Each personality
is developed by characteristic sounds as well
as words, and just a few of those described
are Harrison Garrison, Luck Gluck, Thaddeus
Hop, Hooligan Flea, and the dog w ith the
longest name in the world. A return visit is
paid to Miss Goggins, whose teaching methods
are the despair of a ll modern educators. The
annual release is timed to catch the Christmas
trade, but better shops should keep copies on
hand for birthday gifts.
.IE
AUDIO
•
FEBRUARY, 1961
SERIES
6
STEREO TAPE DECK
.
a superior in stru ment!
, $498
Here's why •• •
•
Jim Copp and Ed BTown: Th imble Corner
Playhouse 303
~,
-----""':""-7
•
•
•
•
•
Recor~ ing
head gap at .00052" w. tor deeper, wider, cleaner signal
impressions on .tape.
'
Playback head gap at .00012 " w. assures optimum perfo rmance
and higher frequency response.
Erase and record heads completely self-demagnetizing.
!leads laminaled wilh special lines! grade Mu melal fo eliminafe
stray field disiortions:'
Record and playback heads each have' lotal of 2,500 windingswith each winding '/2 the thickness of a human hair.
Head cleaning remarkably simple and easy.
All Tandberg un its feature 1W' ips
"The Professional'S Speed 01 the Future"
TANDBERG 6 STEREO TAPE DECK also offers these outstanding
performance featu res:
Sound·on·sound; 4 trac k and 2 Irack slereo & monau ral playback;
4 Irack slereo & mona ural record; Bu ill·i n remote conlrol; Digital
counler; Silenl pause conlrol ; Direct monitor from signal source or
aclive recording; Push bullon operation.
RJandbcJ'8of America, Inc.
a Third
Avenue, Pelham, N. Y.
'73
NEW PRODUCTS
• 72-Watt Amplifier Kit. Taldng its place
beside the ullusually weIJ-designed H. H.
Scott FM tuner kit is this 72-watt amplifier kit, the Scott LK-72 . On the surface
this kit seemS to have a IJ the virtueR of
the tuner kit-that is extreme simpliC'ity
for the kit builder combined with factory
performance standards. From the way
these kits go together it seems that the
designer was ordel'ed to remove the drudgery and leave only the cost-saving fun. In
appearance this amplifier is a pE'l"fE'ct
match for the tuner kit so that the builder
may have a system which is matched in
appeamnce a" weIJ as perfnl'mance by the
time he Is finished. S.peciflcatioll!" for the
LK-72 read like those for any factory -assembled unit: fuIJ power 72 watts (36
watts per channel); IHFM power band
extends down to 20 cps; total harmonic
distorti on is less than 0.4 per cent at full
power; hum level is better than 70 db below fuIJ power output. Among the many
additional features of the LK-72 are a
"center channe l" level control, scratch
filter, tape recorder monitor, and separate
bass and treble control for each channel.
The H. H. Scott Model LK-72 I'eta ils for
$149 .95. H. H. Scott, Inc., Dept. P, 111
Powdermill Road, Maynard, Mass.
B-l
• Unique New Mixer. UltrAudio Products,
. a division of Oberline Inc., has Introduced
a mixer amplifier offering features herE'tofore unavailab le in either professi ona l or
home units. Designated Model M - 5 CustoMixer it is available for rack, conRole or
carrying case use. The amplifier offers five
mixing positions for microphones, phonos,
tuner, tape output, etc., and a master gain
control, with high and low impedance inputs and output, illuminated VU meter,
turntable cueing, and equalizing. The mixer
utilizes a standard 5 'A, x 19 in. panel,
weighs but 20 pounds, complete with selfcontained power suppl y. Special features
al'e the plug-in input transformers and
preamps which one buys only if needed,
and the patented "Straight-Line" vo l ume
controls. Replaceable designation strips
permit indication of which source is connected to each mix position. UltrAudio
Products, Dept. P-1, 7471 Melrose Ave.,
Los Angeles 46.
B-2
• 4-Speed Transcription Turntable and
TOLe Arm. Each unit engineered to complement the other, Lafayette's new 4speed turntable and tone arm are supplied
74
on a singl e mounting p late. Designated as
Model PK-449 they are priced at only
$49.50. The tUl"ntabl e features a heavy
duty 4-po l e induction motor, free floating
"nd Rhock moullt ... d tn e lil11111 ate vibration.
The 3-pound. rim-weighted, 12-i nch alumi-
-
- -~
/'
,;;.-
nllm table is constructed with a permanently lubri cated oilite bronze bearing
while the spind le turns on a sing le ball
beal"ing. Speeds are se lected by means of
a clicl,-in shift lever and the idle r is disengaged in the off position. A fine-speed
control permits a djusting the speed up to
plus or minus 7 per cent . Noise and rum ble are 50 db below average recol'ded level
with wow and flutter l ess than 0.2 per
cent. The 12-in ch tone arm is easily adjusted for different stylus forces by me" ns
of a knob at the r ear of the arm. Additional feat ures inc l ude a plug-in h ead
and an ON/OFF switch lo cated In the a rm
rest; simply lift the tone arm to start the
motor and rep lace in the arm rest to stop
it. Supplied w ith a strobe disc, 45-rpm
adapter, shielded hook-up c"b les. Lafayette Radio Corp. , 165-08 Liberty Ave.,
Jamaica 33, N.Y.
B-3
• Speaker System Kit. Solving the perplexing problems of enc l osing e lec t rostati cs or of finding a woofer whose effic iency
and sound " character" m"tch the electrostatic units, the new JanKit manufactured
by Neshaminy Electl'onic Corp. contains
an electrogtalic mid- and high-range
sp.,,,ker, it" power supp ly, a nd a matching
woofer-all pre-mounted on a rigid 19 'h
by 16 inch pa.nel designed for custom installation in a l ocation of your own choosing. Mid- and high-frequency reproduction
in the JanKit 41 comes from a J anZen
electrostatic speaker whose two push - pull
radiators are stated to produce uniform
frequency response from 700 to beyond
30,000 cps. Bass Is provided by a Neshaminy Mode l 350 ll-Inch woofer. This
highly compliant speaker is specifically
designed to match the J"nZen electrostatic
and tt.. retain full efficiency down to 30
cps in enclosures as small as 2 cubic feet.
Priced at $99.95 the JanKit 41 comes with
CnmlllE'te instructions for building an Inexpen>"lve, shelf-type enclosure or for
mounting in exi sting cabinets. Neshamfny
Electronic Corp., Neshaminy, Pe1lna. B-4
• SO-Watt Stereo AmpUfier. Sherwood's
!l1"de l S-5000 II is an 80-w"tt (muRIc
p"wer) stel'eo amplifier and preamplifier
and I" an improved model of the Sherwood
S-5000 The S-5000 II provides eilher
stel'eophonic or monophonic system operatinn wit h only one set of basic controls,
yet offers E'very important control fe"ture
eRsenti,, 1 to stereo or mono operation .
ThE'Re include 10 two-ch"nnel controls,
SlereO nnrm" l /reverse switch , phase In vPI'Rinn s\v it c h, and dual amplifte l~ monophollic operation with either set of input
!,OlJr'·.,,,. 'rhe five modes of opf'rntlon
(stereu, stereo-revel'sed, n10n o 1, mono 2,
n,ono 1 + 2) are se lected by a function
switch which also operates a corresponding group of indicator lights to identify
the se lected mode. Other features include
presence-rise switch, phono chamlel hum
a lld noise 60 db below rated output, and
phono Rensitivity of 1.8 mv. Thel'e is also
a "third channel" output. Price is $199.50.
Sherwood Electronic Laboratories, Inc.,
4300 N. California Ave., Chicago 18,
Illinois.
B-5
• Electrostat-2 Full-Range Speaker System. Io'eaturing a 4-e lement eleetrostalic
tweeter, the new Electrostat-2 introdlJ ced
by Rll(\io Sh"ck of Boston is intended to
provide good sound quality at a reasonab le price. The highs in thi" full-range
system, as previously indicated, are
h" nelled by a
4-element electrogt" tic
tweeter which is placed so that a 120-degree dispers ion is achieved. The lows are
handled by an 8-inch woofer. Crossover
frequency is 7500 cps and l evel attenuator
is included to permit sensitive balance of
thE' highs. An ON/OFF switch is provided
to control the electrostatic element. Frequency range is stated as 30 to 25,000 cps
for the system . Power handling capacity
is 20 watts, impedance is 8 ohms. In addition the Electrostat- 2 is available in a
choice of two decorator cabinets: genuine
mahogany or imported teak. Radio Shack
Corp., 730 Commonwealth Ave., Boston 17,
Mass.
B-6
• Economy Tape-Head Demagnetizer. A
new economy priced tape hea d demagnetizer which will remove permanent magnetization-a significant cause of h;gh
noise level and harmonic distortion-has
been announced by Robins Industries.
Known as Model HD-3, it features a special plastic sleeve on the tip of the probe
AUDIO •
FEBRUARY, 1961
BREAKTHROUGH
DBRI(JH!
New LK- 72 72-Wa tt stereo complete amplifi er kit (left), $149.95. LT-IO Wide -Ba nd FM Tu ner kit (2.2I'v se nsitivity). $89.95.*
H. H. Scott takes totally new approach ...
makes Kits easier-to-build, better-performing!
BREAKTHROUGH! _ Here,
for the first time, are kits with
t he performance, features and
handsome good looks of H. H .
Scott factory-assembled components ... kits that are a real
pleasure to build and so expertly designed that you can
achieve professional results in
just a few hours.
H. H . Scott assures you the
performance of factory-built
units with these innovations:
1. All mechanical parts su ch
as terminal strips and tube
sockets are firmly pre-riveted to the chassis thus assuring
sturdy professional construction and eliminating the bother
of this time-consuming operation.
2. Every wire and cable is already cut to exact length and prestripped. This saves you time and assures professional performance because exact lead length is automatic.
3. To take the guesswork out of assembly, electronic parts are
mounted on special cards in the order in wh ich they are used.
No loose bags of parts to confuse you.
.
4. Full color diagrams in easy-to-follow instruction book
simplify assembly and reduce errors because you match t he.
part to the color diagram.
HERE'S WHAT ENTHUSIASTIC OWNERS SAY:
" ... designed to professional sta ndard s; sou nd abso lutely clean, very
se nsi tive ; instru ction book of out·
standing clarity." - Major B. W.
Cotton, Jacksonvi ll e, Ark.
" Loo ked long for the best ki t - and
found it ... best instructions I ever
saw, unbelievably simpl e to build." M. Greenfield, White Plai ns, N. Y.
" . . . I woul d run ou t of su perlati ves if I
•
-"
<
tried to adequately state how I feel
about this tun er .. ." - Samuel R.
Harover, Jackso nville, Ark.
" . .. without a doubt the easiest kit I
have ever built (out of 11 ) ... " - B.
P. Loman, Jr., Rochester, N. Y.
" . . . fines! kit I have eve r bldl!. And
one of the fine st tuners I have heard,
kit or otherwise." - -A. J. Zilker,
Hou ston, Texas.
H.H. SCOTT
H . H. Scott In c., III Po wder mill Road, Maynard , Mass.
Rush me complete techn ical specifications on H. H. Scott kits.
Include your new "1961 Guide to Custom Stereo."
Dept. 035-02.
______________________________________________
l\Tan~e
~
Address' _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __
City __________________Zone _ _~S tale_____________
*Pr-ices slightly higher West oj Rockies.
Export : Telesco International Corp., 171 Madison Ave., N.V.C.
that prevents accidental scratches to the
tape. The spec ially shaped probe m akes
any head accessible and the HD- 3 ca n be
used equally well for both monophonic or
stereophonic tape h eads. Claimed to be the
first quality, low cost, A meri can-ma d e
d emagnetizer, the HD-3 is priced at .$5.95
which Should make it very attractive t o
amateur tape fans . Rob ins Indus tries
Corp., Flushing 54, N. Y.
B-7
• New Erase Heads. The Nortronics Company h as ann ounced a n ew line of stereo
and monophonic e r ase heads for u se w ith
two- and fo ur-tracl, magnetic tape mac hines. Three basic mounting styles facilit ate the installation of the HQ series
heads in a ll types of t a pe recorders.
Double-gap constru ction is u sed fo r clean
eras ure with minimum power requirements. The tape comes into contact with
on ly the polished metal face , givin g long
life, l ow tape f riction, and fre edom from
oxide loa ding . The heads are ava ila ble in
two impedances: the No. 1 high impedance
head requires appI'oximat ely 115 volts at
60,000 cps; the No.4 low impedance model
operates with 35 volts a t 60,000 cps.
Further information and specifications
from The Nortronics Company, In c., 1015
South 6 Street, Minneapoli:> 4, Minn . B-S
• Integrated stereo Amplifiers. Two new
integrated stereo amplifiers, the 70-watt
ST70 and the 40-watt ST40 (shown), h a ve
been introduced by Eico. Both amplifiers
are able to handle a ny stereo program
source: FM-AM radio, FM-Multiplex, magnetic cartridge, cera mic or crysta l cartridge, tape head, or prea mplified tape. Controls include selector switch, tape monitor
switch, sepa rate level and balance con trols, balance check switch, scratch and
rumble filters, loudness-level switc h, and
individual feedback-type bass and treb le
tone controls for each channel. The ST70
has, in addition, a tape speed equalizer
lor the money
circuit by
•
tubes by
.HIII!""hll.!,~';~-'lI!!,·F~k;;:a:rd:;:o:n:-11 ~ Amp ere XII
and a g.peaker Phase rever;:;al . switch. Frequency r esponse of ·the ST70 is stated as
plus or minus lh db from 10 to 50,000 cps
and h armonic distortion is less tha n 1 p e r
ce nt from · 25 to 20,0 00 cps. The dual power
amplifiers of the ST40 are Williamson-type
circu i ts empl oying voltage am.plifier s a nd
split-l oad phase inverters driving the output sta ge. Frequency response of the ST40
is sta ted to be plus or minus 'h db from
12 to 25,000 cps; harmonic distortion is
less than 1 per cent from 40 to 20,000 cps.
The ST70 sells for $94.95 in kit form,
$144.95 wired. The ST40 sells for $79.95
in kit form, $124.95 wired. All prices inc lude metal cover. Eico Electronic Instrum e nt Co., Inc., 33-00 Northern B l vd.,
L.I. C. 1, N.Y.
B-9
High gain .. . low noise ... absence of microphonics ... low
distortion ... reliability - these are the primary qualities
circuit d esign ers look for in electron tubes. Once again,
Harman-Kardon en gineers h ave found these qualities
best exemplified in Amperex tubes. Small wonder, then,
that the tube complement of the new Harman-Kardon
"Stereo Recital" Model TA224 Integrated Stereophonic
Receiver includes four Amperex 12AX7/ ECC83's, one
about hi-Ii tubes
tor hi-fi circuitry
• Stereo Receiver. Following the same design principles as the Fisher Mode ls 600
and 800, the new 500-S, priced a t $349 .50,
is Fisher's a nswe r to the need f o r a quality FM-AM stereo receiver at a rela tively
modera te cost. The 500-S is a completely
integrated system of m a tched Fisher c omponen ts on one c hassis. All tha t is required for a complete system is a pair of
speakers and a record player. S ensitivity
of the FM tuner is 0.9 microvolts for 20
db of quieting with a 72-ohm antenna ;
1.6 microvolts with 300,ohm antenna.
A.g.c. on FM and a.f.c. on AM maintain
12AU7/ ECC82, and two 6AtJ6's.
These and many other Amperex 'preferred' tube types
have proven their re li abi l~ty and uniqu e design advantages in the world's fin est audio components.
Applications engineering assistance and detailed data
are always available to equipment manufacturers. Write:
Amperex Electronic Corp., Special Purpose Tube Division, 230 Duffy Avenue, Hicksville, L. 1., N ew York.
OTHER AMPERE X TUBES FOR QUALITY HIGH-FIDELITY AUDIO APPLICATIONS
POWER AMPLIFIERS
6CA7/EL34 : 60 w. di stributed load
7189: 20 w., push·pull
6BQS/EL84: 17 w., push·pull
6CWS/EL86: 25 w., high current,
low voltage
SBM8/ECL82: Triode-pentode, 8 w.,
push·pull
VOLTAGE AMPLIFIERS
6267/EF86: Pentode for pre·amps
12AT7/ECC81: Twin triodes, low
12AU7/ECC82: hum, noise and
12AX7/ECC83: microphonlcs
SBL8/ECF80: High gain, triode·
pentode, low hum, noise and
microphonics
1
76
RF AMPLIFIERS
6ES8: Frame grid t win triode
6ER5 : Frame grid shielded triode
6EH7/EFI83: Frame grid pentode
for IF, remote cut·off
6EJ7 /EFI84: Frame grid pentode
for IF, sharp cut·off
'SAQ8/ECC85:
Dual triode for FM tuners
60C8/EBF89: Duo·diode pentode
RECTIFIERS
6V4/EZ80: Indirectly heated, 90 mA
6CA4/EZ81: Indirectly heated, 150 mA
SAR4/G134: Indirectly heated, 250 mA
INDICATORS
6FG6/EM84: Bar pattern
IM3/0M70: Subminiature "excla·
mation " pattern
SEMICONDUCTORS
2N1517 : RF transistor, 70 me
2N1516: RF tranSi stor, 70 me
2N1515: RF transistor, 70 me
INS42:
Matched pair discriminator
diodes
IN87A:
.AM detector diode,
subminiature
t h e desired volume leve l at a ll times. The
a udio co ntrol center h a s a tota l of twenty
controls and switches, the controls being
gro uped functionally to make ope r a tion
simple for even the "unin itiated." The
dua l-channel power amplifier supplies 45
watts-music power rating. There are 13
i np u ts and 5 outputs on the rea r panel,
including a "center channe l" o utput. The
Fisher 500-S is 17 inches wide, 4 13/ 16
inches high, and 13 % inches deep. Fisher
R a dio Corp., 21- 21 44th Drive, Long
Isla nd City 1, N .Y.
B --IO
AUDIO
•
FEBRUARY, 1961
k nig1!!:,kit®
NEW LITERATURE
• Pocket"Size Aid for Planning Stereo
Sy stem. Pickering & Company has just
published a b roch u r e e n ti tle d "TechSpecs" which was written an d d esign e d
to assist t h e a u diofan in p lannin g a s t ereo
high-fideli t y system. Pocke t -size, "Tech Specs" is a g u ide w h ich h e lps p la n for
needed space an d coor d inates the components to the encl osur e or cabin et. Contents in clu d e a p lannin g c h art and complete technical specification s of the line
of Stanton Stereo Fluxvalves. Available
at no cost by writin g to D ept. PR6, P i ckering & Company, Sunnysi de Bou levard,
Plainview, New York.
B-ll
• Allied's 1961 High-Pidelity Catalog
B eady. Allied Radio a nn ou nces the availab ility of i ts 196 1 catal og. Consisting of
444 pages it lis t s more than 40,000 item s.
I n a dd ition to Allied's own Knight li ne of
components a complete lin e of other famo u s brand names are in c lud e d . F ea turing
extensive lis tings of compon e n ts, the a l lied catalog a lso in c lu des a wide selection
of complete systems. "Do-i t -yo u rself" en thu s iasts wi ll find a greatly enlarged
selection of Knight-Kits. I n clud ed are
basic amplifiers, stereo and monophonic
amplifiers, preamps, tuners, a uni versal
stereo tape recorder -playback preamp,
a n d speaker enclosure kits. A complete
selection of fu r niture to house a ll highfi deli ty components is fea t ur ed in this
year 's catalog. A l so inclu ded are l istings
of specially sel ected s t ereo r ecord s a nd
recorde d tapes. T his catal og is availab le without char ge upon r eq u est. Write
to A llied R adio Corp oration, 100 N. Wes tern Ave., Chicago 80, Ill.
B-12
• Loudspeake·r s and Equipment Cabinets.
L isting their comple t e line of h igh-q u a lity
speakers, speaker systems, equ ipmen t
cab inets, a nd crossover networks, this
new brochure f.rom R . T. Boza k Sales
Company provides a compre h ensive description an d t ech nical specifications of
a ll t h e pro du cts l isted. Free copies m ay
be obtained fro m any Bozak d ealer, or by
wri ting to R. T . Boza k Sa l es Com p an y ,
Darrien , Connecticut.
B-13
• New Jense·n Loudspeaker Ca.talog. A 24 page l ou dspeal<er catal og is n ow availab le
w ithout cost from J ensen Manu f act urin g
Com p a ny, 66 01 S. L a r a mie Ave. , Ch icago
38, Il lin ois. Catalog 165-F con tains: a
g u ide for p lannin g s tereophonic a nd monoph onic systems a s w e ll as convertin g
monoph onic systems t o ster eo; com p l ete
descri ptions, specification s, a nd illustr a tions of complete lo udspeaker systems and
cabinets; lou dspeaker k its ; and the comp lete J ensen compon ent li ne. A l so d escribed are t h e p r inciples of oper ation of
the J e nsen high compl ian ce F lexair woofers and t ube-vented Bass S u p erflex en closu res.
B-14
• Audio Dynami cs Corporation, 1 677 Co dy
Ave. , Ridgewood 27, N . Y., m anu fact urers
of t h e ADC line of s t ereo cartri d ges, mak es
availab l e a free, m ulti-col or e d b rochur e
descr ib ing t h e AD C-1 car trid ge. Inc lu ded
in t h e broch ure are compl ete techni cal
specifications of t h e cartri d ge p lu s a d escription of how t h e unusually h ig h-q u a lity performance is ach ieved.
B - 15
• Guide to Hi Pi. A new 36- page bo ok let
expla ining in c lear langu age the fundamen tals of monophonic and stereophonic
sound r eprodu ction h as been p ub lished by
Eico. Written by Mannie Horowitz of
E ico 's engineering d ep a rtment, the bookle t covers such s u bjects as t h e factors
comprising h igh fi d el ity (includin g sections on the nature of so u n d a nd t h e prob lems t h at a so und r ep ro ducing system is
face d with ) ; the c omp on ent p a rt s of hig hfide lity system s ; t h e m ean in g of ster eo,
a nd h ow to convert a mono system to
stereo ; a nd how to save money when b u ying high-fi de lit y e quip ment. The b ookl et
is availabl e from Eico, 33- 00 Nort hern
Blvd., L on g I s la nd City, New York for 25
cen ts.
AUDIO
•
FEBRUARY, 1961
a pleasure to build and you own the best
you get more with a Knight-Kit:
custom quality ... exclusive design developments ...
maximum savings ... supreme listening enjoyment
knight-kit Stereo Tape Record-Playback Preamp Kit
Compl ete record -playback preamp for any 2 or 3 head stereo tape transport.
Separate dual -channel recording and playback preamps . Permits tape
monitoring, "sound-on-sound" and "echo" effects . Features : Accurate VU
met ers; adjustable bias and erase voltages; concentric clutch-type level controls
for mi xing of mike and au xiliary inputs on each channel, for channel balance
and for master gain adjustment; 6-posltlon selector switch selecting every
possible stereo and monophonic function. Printed circuitry for easy assembly .
Extruded aluminum panel in Desert Beige and Sand Gold; 4Ys x 15)1, x 9".
Shpg . wt., 15 Ibs. 83 YX 929. $5 Down. Only $79.95 (less case).
new
and
exclusive
wide choice of money-saving stereo hi-fi knight-kits
20-Watt Stereo Amplifier Kit
83 YX 927 . $39.95
70-Watt Stereo Amplifier Kit
83 YU 934. $119.95
32- Watt Stereo Amplifier Kit
83 YU 933. $59.95
40-Wat1 Stereo Amplifier Kit
83 YU 774 . $76.95
Stereo FM-AM Tuner Kit
83 YU 731 . $87.50
Prices include case
KnIght-Kits are products of and
unconditionally guaranteed by
FREE 1961
ALLIED CATALOG
See the complete KnlghtKit line of hi-fi components . For everything in
build-your-own hi-fi , for
everything i n Electronics ,
get th e 444-page 1961
Allied Catalog . Send for
Free copy today .
Easiest Terms:
Only- $5.00 down (or less)
on orders up to $200; up
to 24 months to pay .
KnIght-Kits are
available in Canada
FM-AM Hi-Fi Tuner Kit
83 YX 928 . $49.95
ALLIED RADIO
------~-------------,
ALLIED RADIO, D ept. 138- 81
100 N. Western Ave .• Chicago 80, III.
Shi p th e loll ow i ng Knlght-Klt s: _ _ _ _ _ _ _ _ _ _ _ __
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ $ _ _ __ enclosed
o
Send FREE t96t Catalog featu,lng Knight-Kits.
Name'- --------------------I
I
Addres s
ICily
L __
I
I
I
I
I
I
I
I
I
-------------------~
77
Zon e- - - s t. te
TRANSFORMERS
•
Transformers for Transistor Circuits
•
Input Transfomers
•
5 A N 5 UI
•
Power Transformers
•
Output Transformers
E LEe, RIC
co.,
Choke Coils
L' D.
460, Izumi-cho, Suginami-ku, Tokyo, Japan
Circle 7SA
for
those
the
who want
GOOD sound
MOVICORDER
is a sound
recording
investment
Skillful, o ld country craftsmanship and up to the minute engineering
has been combined by Movic of Denmark · to produce a recorder surpassing
others costing far more. Ruggedly constructed and extremely compact,
the MOVICORDER is the culmination of years of experience in designing
and manufacturing recording equipment for professional use.
•
•
•
3 motor drive
Perfect timing
No change in tape speed
from start to end of reel
•
2 separate channels
Provision for installation
of a synchronizing head
•
•
•
•
Portable or rack mounted
•
Sound-on-sound
Echo chamber
plus many more features.
Write for bulleti n No. 1
M 0 V ICC 0 M PAN Y, INC.
12432 SANTA MONICA BLVD.
LOS ANGELES 25, CALIF.
Circle 78B
78
.
~
ABOUT MUSIC
(from page 67)
phony, is perhaps the most familiar excerpt
from the "Christmas Oratorio." Mr. Randolph depnrted from the 'traditional'
tempo, ranging from adagio to andante,
and chose instead andante qua.~i allegre.tto
(halfway between andante and allegretto)
to emphasize the airy texture of the score.
Because of the faster tempo, the strings
tended to slur the dotted eighth-note figures
and ru sh th e beat. The players were reminded to attack the phrases precisely and
not allow the gently tripping 12/8 rhythm
to develop into a slow jig. The accompnnying photograph (Fig. 1) was taken during
a rehearsal of this movement (in a different location). Note the left hand, cupped
to indicate a rising phrase, and the right
hand, drawing a figurative bow.
The leitmoti v of the rehearsal was 'bal·
ance'- "A little less instruments here, just
a touch more solo." "Softer, tenors!"
"Altos, more body to tbe tone." "Up orchestra, down chorus!" This last instruction crystalli zes Mr. Randolph's approach
to performan ces of Baroque chorlll mnsic.
"Historicn lly speaking," he said, "our
chorus is eight times too large. Bach rarely
worked with more than thirty voices. Despite this, it has been my intention to avoid
the m assive nineteenth-century sound that
still ruins many Bnch performances nowadays. I wanted each sixteenth note to be
heard and e,ery word distinrtly projected.
Clarity and lightness, not blurred lines an d
thick texture, are my goals." Mr. Randolph
held the reins of dynamics firmly. There
were moments when the chorus took on the
sound of an intimate ensemble, although,
looking over the Sill gel's, one had the impression thnt, if they felt like doing it,
they could have easily huffed ani! puffed
a nd blown the orchestra and soloists right
off the stage.
The numerical disparity between chorus
and instrumenta lists WIlS consirl ernhle. The
orchestra approximated in size that employed by Bach when he produced the oratorio for St. Thom as's Church in Leipzig
(1733-4): in the Carnegie Hall performance, there were 8 first violins, 7 second
violins, 6 violns, 4 celli, 3 doublebasses; 2
flutes, 2 oboes, oboe d'amore, bassoon , 3
trumpets, 2 French horns, timpani, harpsichord and organ. Th e ·chorus numbered 225.
Mr. Randolph nevertheless struck a happy
balanr,e between the two forces.
It was a distinct p leasu re to hear this
well-rehearsed, rarefully disciplined ehorus
reach the point in the rehearsal at which
the music took over and a ll sang as one.
This fusion of voices is possible more often
when a choir sings for its own leader than
when it is imported by an orchestral conductor for an occasional concert. "Members
(of a chorus) ," wrote Virgil Thomson (in
The New York Herald Tribune, l\Iay 9,
1943 ), "will sing in pitch and in tune (for
the latter, nnli) will obey him with vigor
and all promptitude. But their work will
not have the poetry, the personn lity, the
E'xpressive variety that it has unller the
man they are used to, the man with whom
they have an accustomed spiritual intimacy."
IE
AUDIO
•
FEBRUARY, 1961
CUSTOM CONSOLE
(from pag·e 19)
of fast changing developments in the
audio component field, and their effects
on obsoleseence, we designed the control panel and the attached supports,
such that the unit is entirrly removllhle.
Two screws are used to fasten the panel
assembly. For instance, should it become necessary due to a future acquisition of a multiplex unit, the sum of less
than $5 (coupled with a morning's effort) will find a new panel and support
assembly framing the revised "front
ends".
In the same vein, future purchase of
the almost inevitable tape machine, will
find a generously spaced home in the
right hand lower compartment now occupied by a patented, slide-out, record
storage rack (Fig. 6). The space available for tbe tape instrument is designed
to accept rack mounting type recorders
as well as the more diminutive portable
instruments. As the reader may well
reason, audio custom design is not all
black and white! This addition of a possible tape instrument is obviously confined deep in stllge one!
Lastly, several features were incorporated which are well nigh invisible, but
do much towards adding convenience
and mobility to the entire system. Previously mentioned, there is the inclusion
of the sliding record rack. In connection with the turntable compartment,
looking at Fig. 7, one notes the use of
a lallip. This lamp is automatically
switched by a push-pull pressure switch
operated by the door closure. This feature was added at very reasonable cost
when I discovered a General Electric Co.
automatic closet lamp fixture for under
$2.00! In conclusion, the entire console
(in operating rondition weighing some
200 pounds) is mounted on four 2-inch
rubber tired casters so that the efficient
housewife is not hampered in her tidying up. The console rolls quite easily at
such times!
Many excellC'nt treatises are availahle
on the manner and methods of wood
finishing. The only comment necessary
here is that the basic ingredirnt needed
to acquire that professional hand-rubbed
look so desired by all, is simply hand
sanding and polishing! No smnll contribution to the sheen of the final finish,
were the long hours sprnt sanding and
polishing (with 4-0 steel wool) the unstained raw wood. This was an extra
smoothing operation in addition to the
polishing done after staining and between each of the three successive coats
of lacquer. The whole ensemble is
stained a platinum walnut. The color of
this stain is beautifully enhanced by this
lengthy but rewarding process.
AUDIO
•
FEBRUARY, 1961
SARKES
TARZIAN
TAPE
Engineered for Highest Fidelity
•
High Output-can accept signals
with dynamic range to realize the
full potential of even the finest
professional equipment.
•
Wide-Range Response-virtually
flat response for all recording frequencies .
•
Low Distortion-distortion is less
than 2Y,% at maximum record level
as measured by Navy Specification W-T-0061 .
•
High Uniformity-uniformity within a 1200-foot reel is within plus
or minus X db . A new oxide formula and special selectivity of
oxides protect recording heads
from wear and prevent abrasion.
•
Humidity and Temperature Protection-special coating, priming, and binding techniques help
keep Tarzian tape in new condition longer in ordinary good tape
storage conditions.
····
·
.................•.......•..•.··
Here is a tape that you can safely (and
wisely) adopt as your personal "standard" tape. It is a professional quality tape
that carries the same list price as many
tapes of inferior quality. Consider that
inferior tapes frequently damage record~
ing heads by abrasion; that their con~
tinuous flaking reduces recording-head
sensitivity; that the quality of sound is
evidently poor even on immediate play~
back and that it rapidly deteriorates fur~
ther in storage. Compare the quality char~
acteristics of Tarzian tape listed at left.
Tarzian tape makes every tape recorder
perform at its very best. Prove this to
yourself with your personal listening test.
There's a written guarantee in every box!
Ask your dealer for Tarzian tape. If he
cannot supply you, send us his name,
and we will see that your needs are
promptly supplied.
SARKES TARZIAN, INC.
World's Leading Manufacturers of TV and FM Tuners. Closed Circuit TV Systems. Broadcast
Equipment. Air Trimmers. FM Radios. Magnetic Recording Tape. Semiconductor Devices
MAGNETIC TAPE DIVISION. BLOOMINGTON. INDIANA
Export: Ad Auriema, Inc., New York
79
PERFECT IIHEARJJ-PHONES
THE BEYER DT 48 DYNAMIC HEADSET.. . FOR DisTORTION
FREE REPRODUCTION OF SOUND ... EVEN AT HIGH
LOUDNESS LEVELS ... RESONANCE FREE THROUGHOUT
THE RANGE OF HEARING FROM 20 TO 15,000 CYCLES.
THE"" EAF=lPHONES
TO
MAKE
YOU
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EARPHONES
AGAIN.
COMPLETE
FURNISHED
GOTHAM
SPECIFICATIONS
ON REQUEST.
AU D I 0
WILL
BE
PROMPTLY
CORPORATION
2 WEST 46th STREET, NEW YORK 36, N. Y •••• COlumbus 5-4111
1710
N. LA BREA, HOL.L.YWOOO 28, CALIF •••• HOllywood 5-4111
The First Book of its Kind-No Other Like Itt-
SOUND in the THEATRE
by Harold Burris·Meyer and Vincent Mallory
othing like SOUND in the THEATRE
has ever been published. It is the first
N
book to set forth in authoritative detail what
~
I "
"
you can do with sound by ' electronic control,
and how to do it whenever the source (singer,
musician, speaker, etc.) and the audience are
present together. The book develops the requirements for electronic sound control from
the necessities of the performance, the characteristics of the audience (hearing and psychoacoustics), and the way sound is modified
by environment, hall, and scenery. Sound
sources are considered for their susceptibility
of control and need for it, and the many techniques for applying electronic sound control
are described and illustrated in thirty-two spe·
~fiC pr~blems . From these problems are de-
"
RADIO
'
rived systems and equipment specifications.
Complete procedures are given for: Planning,
assembling, and testing sound control installations-Articulating sound control with other
elements of production-Rehearsals and performances - Operation and maintenance· of
sound control equipment.
THE AUTHORS
During the past thirty years, the authors have developed
the techniques of sound control in opera, open·air amphitheatres, theatres on Broadway, theatres on·the·road and
off·Broadway, in concert halls and night clubs, in Holly·
wood and in the laboratory. Some of their techniques are
used in broadcast and recording as well as in perform·
ances where an audience is present. From their laboratory
have come notably successful applications of sound con·
trol to psychological warfare and psychological screening.
......""-
t
Fig. 6.
Record storage now-tape recorder later.
It is rather evident- that there has
been a deliberate attempt on the part
of the author to minimize the description
and attendant elaboration on detail. This
elaboration was purposely avoided. Any
audiofan proceeding seriously from
stage one to stage two and including in
the planning stage the requirement for
custom cabinetry, must of necessity
tailor his design to his individual specications, both in choice of instrumentation and decor. Very briefly: The author's console scales 50 inches long, 30
inches high, and 23 inches in depth,
while the speaker enclosures were modified (in decor only) from factory plans
included with each speaker component
kit.
The solutions presented h erein, particularly that of laminated case construction, are sufficiently adaptable to
permit their inclusion in the majority
of instances where the audiofan is desirous of having the type and quality
of furniture housing that will be commensurate with the quality of his caref ully chosen components. It is hoped
that the methods of achieving this custom look as presented herein may satisfy
his needs and desires, while consuming
less of his exchequer than were he to
p urchase the equivalent in the trade
III arts.
J£
' ~~--~~! I'-----~I
'~
MAGAZINES, INC. "Dept. 2
"'
Post Office Box 629
~
Mineola, New York
I am enclosing my remillanee for $10.00
Send my copy of
SOUND in the THEATRE postpaid.
(No C.O.D., a1\ books sent postpaid in U .S.A.
and possessions, Canada, and Mexico.
Add 50c for Foreign orders.)
Nama ______~---------------------------Address _________________________._____________
City ________ Zone _
Slale ______ .______
Fig. 7. The turntable-with an automatic
lamp to light the way to the.-sF'lindle.
"ERSATZ STEREO" UNLIMITED
(from page 21)
an independent power amplifier-a speaker channel: the AR-l W, flat up to
Fisher 200-and from that through an almost 100 cps; the 515, flat up to alAltec network with a crossover fre- most 500 cps; the 'woofer of the 604-B,
quency of 1000 cps between the woofer flat from about 4'OQ cps to almost 1000;
and the tweeter. To feed the 515 woofer the 285 horn, flat from about 500 cps to
on the same baffle, another Fisher 200 about 10,000; the tweeter of the 604-B,
power amplifier was fed direct from the flat from about 1000 cps to almost 14,Grommes preamplifier, with the output 000; the 302-A tweeter, flat from about
of this amplifier directed to an Altec 4000 to almost 20,000 cps .
. network with a crossover frequency of .
With allthe ·speakers in operation,
500 cps, the Low output of this unit the quality of sound is impressive. And
feeding the 515 woofer. To assure even little wonder, for, as a glance at the
better bass response, this old 515 was block diagram will show, here we have,
modified to reduce its cone resonance to in fact, a monophonic system of four
23 cps. This was effected by running channels, with three of these channels
a Casco tool around the outside edge of utilizing frequency separation before
the cone, sawing the spiders half-way , power amplification: Why this expenthrough.
sive departure from the conventional f
To feed the Jensen bullet tweeter, an Well, for one thing, as was said earlier,
independent Grommes LJ7 power am- stereo was not only unavailable but genpli1ier is used, its input fed from the erally unheard-of when the Dyers
High end of the Heathkit electronic wanted concert hall realism: For ancrossovek-. ,and its output feeding the other, Mr. Dyer, i:easoned: why not uti302-A through a Jensen network with lize the available speakers and equipa crossover frequency of 4000 cps.
ment in such a manner as to amplify in
With the lowest and the highest ranges each channel only the desired range, and
thus provided for, attention was next thereby at the same time obtain the best
directed to the midrange. On hand was possible control and flexibility !
an Altec 285 multicellular midrange
Needless to say, a system of this kind
horn. Properly placed, this would assure can be even more expensive than stereo.
not only,go.od response but also adequate But it shows .what . can be done to and
dispersion of sound. With an ear to the with a mono system when one demands
€limination of gaps, several locations continuous improvement. It also shows
were considered. The final choice: ceil- how earlier units can be effectively coming level ·of the corner to the far right bined with the latest. Possibly the sysof . the A'I;l,-l W floor woofer. With this tem will in time give way to stereo.
horn angled at about 30 deg. and Meanwhile, there is nothing static about
pointing ,corner to corner, dispersion this system or the :r:esuIts it produces.
is well-nigh .perfect, and virtually free Listening to it, however, one quickly
of the influences of parallel reflecting forgets the experimental aspects, the
techniques that are, and in all art should
surfaces.
Feed for the midrange horn was taken be, not the end but the means to it.
In that respect this installation has
from the High output of the Altec crossover network the Low end of which was brought about another phenomenal
used to feed the 515 woofer, all fre- growth-that of a music library which
quencies above 500 cps therefore being in size and quality can well be the envy
and inspiration of many a professional
directed to the midrange ·horn.·
System response ~ Here it is, per endeavor. And here, heard on this unique
Fig. 7. Frequency
response of the 6
speakers.
AR-1W
ALTEC 285
AL9Ec 515
D
V
I
AL TEC 604(W)
ALT~C lOl(TW)
"
.........
JENS'EN 302A
V
2.
. ..
. ..
FREQUENCY
AUDIO
•
IN
1000
CYCLES PER SECOND
FEBRUARY, 1961
.. .
10000
20000
~ystem
in the cozy livingroom overlook'ng the mountains, the cottonwoods and
' he river, the masters of music come
ITuly into their own, with pre~ence, filelity, dpfinition and perspective ahout
which nothing of the ersatz is discernible.
IE
Primo Dynamic Microphone is
now being used by 7096 of genera l
TAPE GUIDE
t ape- r ecorder m anufact urers in
Japan and gaining a hig h reput ·
(from page 34)
Amona the every kind of dynamiC micro phone units
we are selling the OM-3. DM·4 art' one of the mos>l
p opular. This rully cxc.c:lIcn t microphone units .ne
now brina insb.llc.d into the microphont cases of the
majority of ~~ recordcr manufacturers In Ja~n .
rc..su1tine in a complete a nd perfect tap" recorde-r
microphone. Frequ~ncy responcc: 70 10.000 cis ±3 dB
available Unit
JmtlCCUnc~ .
.cO ohm.
Technical electronic "Know-how"
put to practical use in various
types of dynamic microphones.
DYNAMIC MICROPHONE
WITH
VU
METER
for
Recording-level
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; .
DM-194
DYNAMIC MICROPHONE
WITH TELEPHONE COIL
for Transistor Tape
Recorder &
Office
use recorder_
negative-going voltage at the plate of
V I1 which is transf('rred to the grid of
V 2 ) causing the plate of V! to go positive. The voltage fed from the platp of
V 2 to the grid of V j is therefore of the
same polarity as the original signal on
this grid; feed hack is positive. The same
is true for the voltage fpd from the
plate of V j to the grid of V! , However, the voltages on the grids of V I
and V 2 are of opposite polarity, so that
one triode is in the positive half-cycle
while the othpr is in the negative half.
B-plus is supplied to the plates of V I
and V! through the center-tapped coil,
L. The grid resistors and grid capacitors
of each triode produce a negative d,c.
bias in the same manner as in Fig. 1.
The feedhack capacitor of each triode
forms a voltage divider in conjun!'tiou
with the grid cap acitor. Voltage divider
action lilllits the amount of fepdback to
the grid, preventing the tubes from being driven excessively. In Fig. 4, the
.01-1-' g rid capac-ito!" has a reactance mnch
smaller than 2~,OOO ohms at the bias
frequency, roughly 50,000 cps, so that
the voltage divider consiRts principally
of the feedback and grid capacitors.
Sometimes, to supplement the d.c. bias
ohtained by grid-Ipak action, cathode
hias is also u~ed. That is, instead of connecting the cathodes of the triodes directly to ground, they are both connected
to ground thl'ough a common resistor
with a valu e of several hundred or a few
thousand ohms.
IE
Key Position with IBM in
AUDIO AND
MAGNETIC TAPE
SYSTEMS
DEVELOPMENT
An important position has recently
been created in the advonced development of audio equipment, including
high· fide lity magn tic tope systems.
This openi ng carries sign ificont remunerati""J n and could lead to full
responsibility for all development ef·
forts in these areas.
An
engineering
team,
now
being
formed, will be charged with the reo
sponsibility for applying latest technology to high-fidelity oudio and magnetic tape systems of the future . The
group will function in an atm:>sphere
highly receptive to new approaches
which may accomplish major break-
throughs in systems of this type,
Experience in the audio or mogne tic
tcp4'> ·recording fields is e~sential. In
addition, '>ome experience in transistor
circuit d esign is desirable. Educatio n
mu , t include on MSEE or GSEE degree
with related experience.
As a member of IBM's d evelopment
team, you will be working under the
best possible conditions with the finest
equipment. You will receive ext.:ellent
employee benefits and oPllortunities
for advanced education. Y:lU will be
living in a gro wing community r ~ cog ­
ni-zed for its histcrical, cultural and
scenic values. For further information,
please reply full particulars to:
Mr. A. J . Ronvaux,
Manager Professional Employment
IBM Corporation, Dept. 724B
Lexington, Kentucky
IBM
(!)
INTERNATIONAL BUSINESS
MACHINES CORPORATION
Uim('nsions:
56m / m ( h("ight )x
40m/ m ( width )X
20m / m t thickn ess)
SAVE YOUR
DM-173-T
HIGH EFFICIENCY TAPE
WITH IMPEDANCE SWITCH
SYSTEM DYNAMIC
MICROPHONE
Sprdfiml io ...
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r.tIll......' .
~.i1i.itr:
· 73 4n 1111."_ al I. He
1......... « :
6(IOoh . . . . W" .. " ....... . . rt;1o!,45 ( dia l a
_ ,_
l loiB
U~
lti'''''''"... 1 c ...... t u
l.lI...,
C,rcle 1I.l
82
1'0'.,.
0; ......." " - '
~ ,. )
TAPE NOISE
COPIES OF
(f1'om page 26)
AUDIO
this value, it will be "masked" by the
room noise and will not he heard .
A typical quiet, IiRtening room background noise condition (1) is shown bv
the solid lines. This is given in terms ~f
tones in the hum region, and octave band
noise above 200 cp~. Of course, the noise
If'vel in rooms varies, but the shape remains much as shown.
Figure 2 also Rhows two rpprodu!'ed
noi~e conditions during plllyha pk takpll
from Curve A ani! thl' "!'pikf'~" of Fig.
1. 'I'he onf' Illhpl1p(l Hi!!'h (2) ill for a
volume control setting giving maximum
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AUDIO
I
•
FEBRUARY, 1961
measuring
octave band program readings of 95 db
in an ordinary living room-a level used
mainly to impress friends with the
height of the ]<-'i. The one called Normal
(3) represents a r eproducing level 15
db lower, which is more representative
of a usual domestic listening intl·nsity.
What stands out· is the fa ct that the
shape of the noise curve from the reproduction matches the shape of the background noise with which it competes.
At the High setting noise is audible at
both high and low frequencies to about
the same degree during eompletely quiet
intervals of program. At the Normal
setting the reproduced nois!' would not
be audible in this "typical" room, although it might be in very qui!'t rooms.
But, even in a completely quiet room,
the shape of the reprotiuc-ed noise curve
would remain satisfaetory, because the
actual minimum sensitivity of hearing
nearly parallels the room noise curve.
Weighted Signal.to-Noise Ratio
The effects descrihed above are recognized in cOlllmunication alld noise measurelllent, where frequency "weighting"
of the response of the ml'asuring instrument is used to reduce the contribution
by low frequencies. Usua lly an unweighted and a weighted value are giv!'n,
and this might be a useful conerpt for
tape reproducers. In the case of the re·
suits just preRentl'd, for exalilple, and
using the A w(,ighting scale of a stan,lard sound level meter, the signal-tonoise ratios measured were
Unweighted, C-Scale
53 db (as given
ahove)
74 db
Weighted, A-Scale
These two numhers show that the most
intense noise cOl1lponents are at low frequenci!'S where more can be tolerated,
while the high-frequency contribution is
a great deal lower. If only the unweighted number is given, a recorder
with poor tape or poor construction
could measure n!'arly as well, yet give
prohibitively annoying high-frequency
noise. Thus by adding one additional
number, obtained with a relatively simple addition to standard mrasuring
equipment, a great dpal of meaning
could be added to signal-to-noise ratio
specifications. In the critical listen ill~
r egion good tape recorders give, not the
50 db ordinarily thought of, but 70 dh
and more.
IE
Decorate your home with ...
Living Music
qlLlHHlneL
The v ersa tility and beauty of
Grommes Hi-Fi Equipment makes
it possible for you to place it into
any mode of modern living. Whether
you prefer bookshelf, built-in or
cabinetry, Grommes Equipment
blends into any interior decor.
Grommes gives you brilliant clarity
and reproduction at its finest .. .
superb fidelity with a realistic depth
-truly music that lives.
COMPUTERS IN AUDIO DESIGN
Ask your quality Hi-Fidelity Dealer
to demonstrate Grommes Equipment. You have a surprise in store
for you!
(from page 24)
From mechanics the general expression
for the quadratic response to an input,
y, is:
x
y
K
S2 3/\
-+- S + 1
of~
HI-FI
(18)
ill
DIVISION OF PRECISION ElECTRONICS. INC .
9101 King Avenue. Franklin Park. illinOIS
Fig. 11. Complete
analog of a quadratic response.
:
.: Dept. TJ
• Send coupon today for complete details on Grommes :
: equipment
•
·
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AUDIO
•
FEBRUARY, 1961
83
NEW!
"the best of AU 0 10"
No. 120
THE 4th AUDIO ANTHOLOGY
$2.95 Postpaid
A new compendium of AU.D la knowledge.
Here is a collection of' the best of AUDIO-The AUDIOc1inic
by Joseph Giovanelli ... noted audio engineer and the original
high fidelity answer-man-EQUIPMENT PROFILES edited by
C. G. McProud ... Editor of AUDIO. Here is a wealth of hi-fi
and audio information. Answers to the most important issues
in high fidelity and a valuable reference on the performance of
leading makes of high fidelity components. Volume I $2.00 .
This is the biggest Audio Anthology ever!
Contains a wealth of essential high fidelity
know-how in 144 pages of complete articles by world-famous authors.
No. 124
I
NEW! Greatest Reference Work on Audio & Hi Fi
No. 123
nThe AUDIO Cyclopedia" by Howard M. Tremaine
Up to lIIe minute, incllVling stereo! ••
1280 pages
3400 topics
• 1600 illustrations
Here is one single volume with the most comprehensive coverage of every phase of audio. Concise, accurate explanations
of all audio and hi fi subjects. More than 7 years in preparation-the most authoritative encyclopedic work with a unique
quick reference system for instant answers to any question. A
vital complete reference book for every audio engineer, tec,h ilician, and serious audiophile. $19:95
No.115
McPROUD HIGH FIDElITY OMNIBOOK
Prepared and edited by C . G. McProud,
publisher of Audio and noted authority
and pioneer in the field of high fidelity.
Contains a wealth of ideas, how to's,
what to's .and when to's, written so
plainly that both engineer and layman
can appreciate its valuable context.
Covers planning, problems with decoration, cabinets and building hi-fi furniture. A perfect guide. $2.50 Postpaid.
by Edgar M. Villchur
Right up to date, a complete course on
sound reproduction. Covers everything
from the basic elements to individual
chapters of each of the important
components of a high fidelity system.
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SPECIAl!
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No.112
TAPE RECORDERS AND TAPE RECORDING
by Harold D. Weiler
A complete book on home recording by the author of
High Fidelity Simplified. Easy to read and learn the
techniques required for professional results with home
recorders. Covers room acoustics, microphone techniques, sound effects, editing and splicing, etc. Invahiable to recording enthusiasts. Hard Cover $3.95. Paper
Cover $2.95 Postpaid.
FEBRUARY
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Your cost ONLY $5.00 POSTPAID
This offer expires February 28, 1961
Good only on direct order to Publisher
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AUDIO Bookshelf
RADIO MAGAZINES, INC., Dept. 102
P.O. Box 629, Mineola, New York
Please send me the books I have circled below. I am enclosing the
full remittance of $ .............................. (No. C.O.D.)
All U.S.A. and CANADIAN orders shipped postpaid. Add 50¢ for Foreign orders
(sent at buyer's risk).
.
...,..
BOOKS:
NAM~E
1-10
112
115
120
123
124
05102
__________ ADDRESS, _ _ _ _ _ _ _ _ _ _ _ _ __
CITY_ _ _ _ _ _ _ _ _ _ _ _ ZONL-STAT~E_ _ _ _ _ _--'
~~
where
K=gain
OJ = natural frequency
6 = damping ratio
By comparing (17) and (18) it is seen
that:
~M
(19)
Kd~
(20)
OJ=
6=2
S
K sM
1
(21)
K= Kg
Eavesdropper sensitivity
plus Earwitness fidelity
make AKG's D 24 B dynamic mike
from Vienna a must for every
tape-recordist with a sense of
values - for everyone who knows
the True Sound of Music!
Wide, flat response :
high sensitivity:
strong cardioid pattern:
bass-cut switch - 200 Ohms.
Imported and serviced in USA by
Electronic Applications, Inc.
Stamford, Connecticut.
In order to show how an analog ciris constructed, equation (16) is employed.
Solving for the S2X term equation 16
becomes:
· mi.~t
_ S2X = K(] Sx + K 8 X _ F ( S)
M
M
M
(22)
Putting equation 22 into computer
form is done by using scale factors as
previously shown in equation 5. When
. this technique . is used, equation 23 is
obtained.
.,
., . .
.
". t'{
~'
"
o
_
- k" S-e x -
Kd
Kg
M kx Sex + M k" ex -
kr
M et
(23)
Garrard Div., British Industries Corp.,Port Washingto n, N. Y.
Circle 858
ADVANCE ORDERS
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Audio Magazine
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" Delive ry J a nuary 16, 196 1
AU DIO
•
FEBRUARY, 1961
Constants such as K d, M, and Kg are
not scaled as they will appear as fixed
gains. It is also seen that the scale factor
kx is independent except relative to k f
since it cancels in all the ex terms.
Assume that the voltages on the right
hand side (Se", ex, et) of equation 23
are available in the simulation. These are
then added in an adder amplifier through
gains proportional to the coefficients
Kd
( M'
K.
M'
kf)
.
kxM . ThIS is shown at am-
plifier 1 of the basic analog circuit shown
in Fig. 11. The output of amplifier 1 is
+ S2exo Amplifiers 2, 3, 4, and 5 are
straightforward integrations and sign
inversions to find Sex and finally ex itself. By using these signals as "feedbacks" to amplifier 1 with the proper
gain ratios as indicated, a complete
analog of equation 22 is found. Since
equation 22 is equivalent to equation
18, this is also . an analog of equation
18; the quadratic response.
The main characteristics of the quadratic are the frequency ' and damping.
These quantities are seen to be determined in the analog by the gains into
amplifier 1.
Variations in these gains are analogs
of variations of frequency and damping
of the system described ' by equation
22. Optimum , values can be quickly
determined and translated back to the
actual system parameters.
The general use of the quadratic response has been described because it is
Circle 85A
85
the most common expression III audio
work.
In the tone arm-cartridge combination, for example, this expression apPPal'S three til lies. The spring of the
~tylus, the llJass of the arm and cartri;lge, anu the dailiping of the pivots
for'm one resonant quadratic system. The
~pring of the stylus, the llJaRS of the
stylm;, and the dumping of the signal
pick-off forlll the second. The spring of
the rpcord vinyl lJlaterial, the mass of
the stylus assl'llIhly, and the pick-off
ullmpin~ provide the thir'd,
The ~peaker system contains a quadratic rpsponse with the mass of the cone,
the spring of the cone mounting, and
the dlllllpiug of the magnet being the
paramptl'r's that contrihute.
Other eXllllJplps can be found in microphonps, amplifiers, tape transports,
and tuners.
TO BE CONTINUED
THE SMALLEST LOUDSPEAKER HAV·
ING VALID CLAIM TO FULL RANGE
. . . WITH FIDELITY
The 16 cubic feet of bass horn in the
KUPSCHORN is the least size capable of full
range with minimum distortion. Eight times
that size would be required if room corners
were not utilized. Any smaller speaker. of any
design Whatever. must necessarily sacrifice
quality.
Paul W. Klipsch's stubborn refusal to compro·
mise with size in his design of the KUPSCHORN
is one of the many reasons why it remains the
reference standard for genuinely independent
testing laboratories. As a group of acoustic
scientists at Bell Telephone Laboratori es reo
ported recently. "It is the best sound and best
stereo we have ever heard."
Write for literature on Klipsch speaker systems
and a list of published technical papers by Paul
W. Klipsch.
LIGHT LISTENING
(from page 10)
itself is availllble in both English and Freneh
on the Co llllllbia labpJ. Pnfo!'lunately. not 11 11
1i"1t'IIP!" ,ell!'dllng 1'01' thp Hllllwnti('ity of the
mother tonKIIP wi 11 i m·t'st in the Freneh ,"('rsion ju,1 f"I' the Hake of a few hit 'ongs. Thi,
rplea,e lets on" eat the best pa,·t of the clIl,e.
Then too, I'a I ad"," ', ll'llta on !'ecol'rIR is 100
pel' cent ,"ocalislll. These IY"icR are not handl p(l
by someone who was 111'0 hit'ed to act the
pIII·t on stage. In arlrlition to the fOil I' songs
from "ll'1na La Douce," two other French rlittieN r01l1l1l Ollt 'i ,l .. onp of thp rpeorus. The
re,t of the progmlll offers Ramples of six
AmeJ'if'flD ~h.,ws in the everp!;; u l'(J I'i~ing ,vl'inklt'~ that T'atlll'llOll gi\' es to even the most
fHluiliar English I~· rics. Her intimatp aJlproa('h
in JI,wk Ihe K,,;jP fl'om the "TIII'eepenny
Opel'a" lind the rakish tilt ~he g ives thl'
..... <lI·rls mHke this one of Ihe best things Rhe's
done on I'l'eords. I rl<'itlen til lIy, the mono sound
of this disc hilS the clo,e-to bl'ightnpss thllt
registel's effecth'ely even when playen with a
sterpo pi('kup that drops off in response above
12.000 cps.
Stereo adds soml'what to the nimension of
the voice in Patn"hou's Columbia rlisc. As
part of an ambi li"us project recorden in
Paris. Volume 1 of "Leg Grande Chansons"
wa,tes no time in getting down to cases. In
close-up "tereo as biting as anything producen
in Arneri(·a. the CI'e,un of the Parisian favoriteR roll out in r'apid Ruc,·ession. A particularly welcome feature of the set is the inc lusion of the printed French lyrics of each song
along with ils Ellglish translation.
KliPSCH AND ASSOCIATES. INC
Post Office Box 96 • Hope, Arkansas
Circ le 86A
SAVE MOST! Here's your complete
money-savin~ guide to Hi-Fi, including
products avallable only from ALLIED. See
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I
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---------------------------
PWHIl'T nELIYERY, we will not be nndersoh!. Amplifier" tllpe rer·orrlers. tllners,
etc. Xo cntalogllt". A it· :'Ilnil 'Illotes. Compare.
T.. ;\L I:I'o\\,n ~Ill ..s (' 0"1'., Dept. A, 239 E. 24
St.. l'\f'W Yorl' 10. N. Y.
\\,AXTI-:D: ,\ny back iHRlles of
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east Kpws (ll'inr to 10;-)5. TIntl
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AUDIO from
RCA Tlroa'lPeal'ROn, 28
YOI·k.
I'ERFECT COXIHTTOX Fairchild 524A two
Rpel:'d lip-,yue lurnJahle. I'rl',to RC-10-24
Rturlio tape reco ... le,·. .\ Itec :'II -11 con,lpns"r
mif- rophone .y,tf'l lI. Rr.\ ~ ·In:X mi(·I·onhone.
Original cost !f:!:i00.00 will ,ell ~1 :!OO.OO.
He"o-A I·t ~ollnrl ~II\(lioR. 212 Xorth 12th
Strpet, Philadelphia, l'ennsy l\'llllin.
~A1.F.: Rt~I'po pair . .Tam('s TI. Lnn,ing
two wny Rpenker "YRt('ms. I~OA dri\'er,
17:iD1.H h\'('('ter Hnrl !I('ollsti<- lens, l'\1200
CI·OHHOver. Oak with beige nOfl gold gl'ill clot h .
(,ondit ion : like new. Pdre. ~-I!)ii.OO FOR
\.'.lItol1 Houge. La. ,J. lIi. E,lelman. ;\L D .. 700
COlllmerce Builuing, Baton Houge, La. DI
2-G801.
FOH
3~001
FOR RA I.E: nn.1f trll('k hpnd flsspmhly,
('Ontlilpte 1m' Amppx modpl :l!'i0 or ~!'i1. Us~d
l e~s than 1nO hOlll'S. ("onrlitinn like np\\", FOB
naton HOllge. La .. $100.00 . .J. "I Erlplmnn
1\L D .. 70U ' f'olUrnerce Bultuing. Ba'ton Rouge:
La. D1 2-fiS01.
The World of Suzie Wong (Original
Soundtrack Recording)
RCA Victor LSO 1059
r-UCTI FInELITY RE('OHn~ made from
your talle. l.all:',t Jlrof.."ionnl eqllipment. Hot
Rty IIl R. " 'rile : n&L Souud SI!I'vit'es, Inc., Box
·7r;. New York GG, X. Y. Dept. AT
Now it is Hollywoorl's turn to take a commerf"ial interest in the prohlems of Hong
Kong's Suzie \\'ong. Gporge nuning. the composer of the seOI'e, uses II silllple neYice to
point up the international f"wor of the loca le.
The mood lIlusic hilS jll,t enough Ruggestion
of the Chiu!"e ppntatonie s"a le to s('t apa rt
this album from th!' nozpns of movie jobs issued evel'y fe ..... monlh,. The American intluencp enters In the forlll of original jazz compo,itions as well as strllight rpa'ling" of Ruch
stllndards as Oul oj Nowhp/'e. I'm in the Mond
/o'/' Love, and Hit the UfI(lrl to D,·eam.land
played by a large jazz aggregation. These
pl'obably sound a bit more ent ieing in Tpchnkolor ~url·ol1n(1ingR. The "mood" ol'che~tra
is led by the Engli'h condu('to,'. :'Iluir Mathieson, wlws(' nallle is spldom ahsent from the
oppning crerlits of major TIl'ilish films. The
:-:ouud i!': n f:u' ('ry frllm the narl'ow-thl'oateo
flll'e we hlld from Hollywood when the stereo
(lise first attempted to take in the soun(l
stages.
lIE
,,,\XTED: (1Red Pultec EQP-l feed scrpws
for Presto c utter 11:!. l:\r., 18S. 224 (outside-in). :~ Altec ~reakel'" GO·I-TI IInrl cabine ts.
Lynn OlIver HtU<1108, 250 \Vest 8\1th Street
l'\ew YOI'k 24, N. Y.
'
ELECTRICAL ENCINEER
In New York Metropolitan Area, interested particularly in book transcription, word selective relays, and translating equipment, seeks placpment. This
applicant has g-ood educational fnunilation and 30 years' experience with varied
small equipment development and manufacture somewhat similar to that here
referred. Address CB-l for interview,
AUDIO, P. O. Box 629, Mineola, N. Y.
AUDIO
•
FEBRUARY, 1961
'.AJfjQ~:
ANTENNAE' . , .
SHURE. WESTMINSTER PRODUCE
STEREO RECORD. An unuRual1y illt <'re:-otlng
THE FINEST OF ITS KIND • • •
Get more FM stations with the world's most
powerful fM Yagi Antenna systems.
To be fully informed.
send 30~ for book
"Theme And Varia·
tions" by L. F B. Carini
and containing FM
Station Directory.
APPARATUS DEYnOPMENT CO.
WETHEISFIELD t, CONN
ap]l"'JH('h
to
111er('handising
CClr-
trldges ane1 tone arms iR the ste reo reco"d
commiRRionl'd by Shure Brothers. Inc.
The recording. "The Or(,hestra . . . The
Instruments," No. LS66l. hy 'VestminRter
R e cording Co. iR not for sa Ie hut is avail ahle at no c:harge to huyers of S hure cartridges or tone arms. A('('('rning to Shure.
this re c ord offers an pxcel1ent test of a
steren RYRtem'R c-npahilitieR.
ROBERTS BUILDING NEW PLAN'l'.
""llh l ape ,·e",,,,d ... ,· "" Ie " ~R per ('ent ahead
of p!,ojections for the y ear, noberts E:l e ctrollies h aR hepn forc-ed to expand facilltieR. Th e new 50.000-"'Iuarp-foot plant
which will bl' locat<>d at 5nlR Bowcroft
Ave., L os Angeles, Is sched ul ed for completion on the lRt of March.
ACRO CHANGES NAME. Acro Products
126 DUNDAS ST. WEST. TORONTO. CANADA
have Rt"ongly su"pected theHe many years
- t h ey a,'e in t loe e lectroni c R bUf;iness.
Frllm nnw on th p y'l1 he kno,vn ns the
Aoro Electronic Products Company. In
k.,eping with thi" e'hange Le ona "d Klingsberg has been appoin , pd Executive Vice
President and memher of the Board of
DiI·l'ctors. A 1"0 \Villi am F. Carter has
been appointed aRf;i,.,tant to Chief Engineer
(alld Pr.·,..irt,.nt) Hp"hr'rt r. KerneR.
STROMBERG-CARLSON APPOINTS
v. P. C iellrge J. Di(,'k~y. uf PI'inl'cIOn, ~ .•J.,
haR been app"inlf'd vice preslrlent and
a""istant gene "a l manager of the Stromberg-Cad,.,on f);"i,..illn of General Dyn am ics Corp. IIII'. ni"k ey come" from the
Circle 87D
cOl"l)oration's headquHl' t ers office in New
York, v.. hel' e h .. w a s a~~i:..;tant to Execu-
CANADA
H igh Fidelity Equipment
Complete Lines
•
Complete Service
Hi-Fi Records - Components
and Acces.ories
BLECTRO~UOlCE
SOUND SYSTEMS
tive Vicp. f'residpllt C. nh",.,des :llacBride.
A native of :\'ew York f:'i l y , :If,'. Dicl' ey
'waR pduf'ated in the RidgpWf,nd. N. J.
ELECTROSTATIC TWEETER
THRILLINC
HI FREQUENCY
RESPONSE
ONLY $19.95
ORDER BY
MAIL
cna.iJ.rm~i.'~;:~;'
Circle 87E
HEADS YOU WIN!
You ' ll be a winner by soving "heap plenty" on your
Hi-Fi needs. Write todayl
Ask too for discount catalog A-12.
KEY ELECTRONICS CO.
120 liberty St., N.Y. 6, N.Y.
Circle 87F
HI
FI
or SINGLE COMPONENTS
You'll find our prices low
and service fast .
Write for our quotation
Center Industrial Electronics, Inc.
74-A Cortlandt St.
New York 7, N. Y
Circle 87C
A NOTE TO THE HI-FI BUYER
AIR MAil us your requ irements for
an IMMEDIATE WHOLESALE QUOTATION
Components, Topes and Recorders
SHIPPED PROMPTlY AT LOWEST PRICES
WRITE TODAY FOR FREE CATALOG
a u d i 0 190-A lexington Ave. unlimited
New York 16. N. Y.
Circle 87H
AUDIO
•
equal to
~
From time to time , a component has
appeared on the market which was \las
good as Marantz". Fortunately for our
morale., subsequent investigation has
always proved our position secure, and
strengthened our reputation for making
the finest custom preamplifiers and am·
plifiers in the world. We invite you to
compare the performance of other makes
with Marantz characteristics described
below:
• MOST DEPENDABILITY
Repairs are so rare
thaI MorOnlZ devotes less thon 8 mon-hours per weeA
to service. Compore I
COlllp.ilny 11 :1:-; finally ("lIlltirmpd a f a ct ' v e
Circle 87C
PACKAGE
m
...............
there is
FEBRUARY, 19'61
puhlic 8t'honls and at N'))' I h eaHlern Univel·sity. R~flll'e joining (j enera) Dy n anl i cs
in :I'l a r ch 191iO, III" . Di"key work"d for
John W . Stok"s Cn. of B,,:-:ton. and Johnson & Johnson in New Brm,wick, N. J.
if you are about to buy a tape recorder-
YOU CAN SAVE MONEY!
if you own a tape recorder-
• ENJOY BETTER PERFORMANCE!
GETTING THE MOST OUT OF YOUR
TAPE RECORDER
Model 7
Stereo Console
• LOWEST DISTORTION
I.M. Di s lorlion @
10 v. equiv . pk. RMS . . . ma ximum permissible,_
0.150/0 . typical. - 0. 10/0' Reduces 10 a lew hundredths 01 10/0 below about 5 volts output. Dislor.
lion does ~ increase sig nificanlly at frequ ency
extremes.
• LOWEST HUM & NOISE
Equ iva lent loral
noise input , 20-20,OCIO cps •.. J microvoll max., 0.8
microvolt typical (SO db below 10 millivolts inputJ.
• HIGHEST GAIN AI 1000 cps, RIAA equoliza.
lion.- 0.4 mil/ivol/s. 1400 microvolts/) for I voll
output.
• FINEST CONSTRUCTION
In strume nHype.
precision construction throughout . Basic circuit on
heavy, fully shock-mounted turret-terminal boord.
Wiring neally cabled. Noise-selected Htm resistors.
Power transformer double-shielded with mu-metal
before " potting". Trjple-fillered D.C. l i/ament supply. Fully fjnish ed chassis. Front panel . Va" th ickness brushed aluminum. pale gold anodyzed. wi th
precision-machined matching knobs .
Equalizolion and ton~
conlrol curves matched ;n both channels to 0.5 db.
- I yp ical , 0.2 db.
• GREATEST ACCURACY
by H er'/'lUl,n Burstein
Herman Burstein. noted high fidelity authority. provides information that is worth many
times the price of the book to tape recorder
owners and prospective owners. Written in
non-technical language it provides the answer
to these questions:
• What features are necessary or desirable in
a tape recorder?
• What can I do to get t he best performance
out of a given tape recorder? • How to select
the best tape recorder for the money a nd your
needs? • Special questions and problems
raised by stereo. #251, $4.25
FUNDAMENTALS OF HIGH FIDELITY by Herman
Burstein. How to select the best hi-fi equipment for the money you have to spend-how
to achieve the best performance and realize
the most pleasure from your equipment. #226.
$2,95
STEREOPHONIC SOUND by Norman H. Crowhurst. Saves you hundreds of dollars in .$electing your stereo system. #209. $2.25
REPAIRING HI-FI SYSTEMS by David Fidelman.
Save money! Deals with finding a nd repairing
the troubles. #205, $3.90
HI-FI LOUDSPEAKERS & ENCLOSURES by Abraham B. Cohen. Answers all questions on loudspeakers and enclosures, design, crossover networks. etc., #176 Marco cover•. $4.60; #176-H
cloth bound, $5.50
GUIDE TO AUDIO REPRODUCTION by David
Fidelman, Covers design, assembly and testing
of sound reproduction systems and components. #148, $3,50
at bookstores. or ordn rliTut.' Drpt . A-2
• 30 WAns RMS, per channe l Iconservalively
raled! ±0.2 db 20·20,000 cps.
I'! HIGHEST STABILITY Will
nol oscillal~ under
any condition, with or without load. Compl e tely
stabl e to capacitive loading. Instantaneous re covery (rom major overloads prevents breakup noticed
in other circuit d esigns.
• LOWEST HUM & NOISE Be ller
thon 90 db
below 30 watts, open circuit, with inpu·,. typically.
beller Ihan 100 db below 30 wa lls.
• FINEST CONSTRUCTION Sprague
type 17D
·telephone-quality e lec trolyti cs. Epoxy-encopsulated
mylar coupling condensers. Silicon rectifiers. Cabled
wiring. Metered bios and signal-balance adjustments.
• MOST CONSERVATIVE El34
ourput tubes
opera te coolly, 01 only 50 ma plate current.
• LOWEST DISTORTION AI 30 walls, less
than
0.10/0 harmonic di stortion @ J kc. less IhO;;-O.3%
@ 20 cps. I.M., ~ than 0.5%.
-
The cost? Necessarily a little more ... but
well worth it. Write for booklet 41 P.
·_"'UCES SUOJECT TO CHANGE WITHOUT NOTICE
I
JOHN F. RIDER PUBLISHER. INC .
116 W. 14th St.. New York 11. N . Y.
Circle 878
25-14 Broadway, Long Island City 6, N. Y. ,
Circle 87A
87
ADVERTISING
INDEX
•
79.50
KT -600A In Kit Form
LA-600A Completely Wired
DOWN ~'
S.OO
134.50
• Response 5·40.000 cps ± 1 db.
• Precise "Null" Balancing System
• Unique Stereo and Monaural Control Features
• Concentric Input level Controls
• Easy·lo·Assemble Kit Form.
Sensml',t~
2.2 mv for 1 volt oul. Dual low impedance
"plate follower " outputs 150Q ohms. less than .03%
1M distortion; less than .1 % haqnonic distortion. Hum
and noise 80 db below 2 volts. 14xlQ!Vax41f2". Sh·pg.
wt., 16 Ibs.
Made in U.S.A.
E REMARKABLE KT-6S0 FM TUNER KIT
KT-650Kit
LT -6S0A Completely W
54.50
s.oo
Down
Made in U.S.A.
79.95
• Virtually Distortionless Performance-less
Than .15% Distortion at 100% Modulation
• Sensitivity 3 flV for 30db of Quieting
• Response ± V2db 15·35,000 cps
• Variable AFC
Professional FM laboratory Standard Perform·
anc,e - _ Ci~c~itry_ ..e.'Ppl~Ys .a low noise front
end with ' tnode ' mixer plus double tuned dual
I im iter and wide band Foster Seeley discrim·
inator. IF and Discriminator coils are factory
prealigned-permits playing ! he tu~er ~s soon
as assembly is completed . Pnnted CIrCUit board
and famous lafayette instruction manuals make
kit building a pleasure. 14x%Hxll"D. Shpg. wt.,
13'12 ·Ibs.
T-5S0 lO.O-WATT BASIC STEREO AMPLIFIER K
KT-SSO In
Kit Form
134.50
LA-SSO Completely Wired
S.OO Down
KT -500A In Kit Form
~---~.
LT -50A Completely Wired
124.50
P.O. Box 190, Jamaica 31, N. Y.
City __________________________________________ Zone ____________ State___________________ _
G.....A.F.A."Y'ETTE - - - - - - - - - - - - - - -
88
<>
NEW YORK
I
NEWYORK.13,N.Y.
PLAI
, N.J.
Belden .. .... .. ... . .. • . . . . .•. ..... • 5
Bel Canto, A Subsidiary of Thompson
Ramo Wooldridge. Inc. ... .. .. , .. ... 33
Bogen - Presto, A Division of the
Siegler Corp. . . . ..... :.. . . ... . . ... 53
British I ndustries Corporation •.. . .. . 3, 85
Center Industrial Electronics, Inc. . . . .. . 87
Classified . . .... ... ......... ... . . ... 86
Crosby Electronics, Inc. . .. .. . . . . ..... . 71
EICO . . . ........ . .... .. ..... . ......
Electron ic Applications, Inc. ..... . . .. . .
Electro-Sonic Laboratories, Inc. . . . . .. . .
Electro-Voice, Inc. . ... . . .. .. .. ..... .
Electro-Voice Sound Systems, Inc. . ... . .
13
85
59
25
87
Fisher Rad io Corporation . ...... . . . .. .. 9
Fukuin Electric (Pioneer) •.. . . ... .. . . '. 47
Garrard Sales Corp. .. . . .... ..
Gotham Audio Corporation ....
Grado Laboratories, Inc. . ......
Grommes, Division of Precision
Electronics, Inc. . ..... . . . ..
Harman-Kardon
. .. .... 3
. • .... . 80
... .. .. 72
. .•.... 83
. .............. . .... 43
I nternational Business Machines
Corporation . ........ .. ... .. . . ... . 82
87
87
70
86
BRONX 58, N.Y.
PARAMUS, N.J.
Peerless Electrical Products, A Division of
Altec Lansing Corporation .. . . . .... . 10
Pickering (,0 Company, Inc. . . . . . . . . .. . 17
Pilot Radio Corporation .. . ... ..•. .... 7
Primo Company, Ltd. • ... ...... . .. ... 82
RCA Electron Tube Division ....... Cov.
Radio Shack Corporation . ... . .. . .... .
Rek-O-Kut Company, Inc. .. . .•... ...
Rider, John F., Publisher, Inc. . . . . . . . . .
Roberts Electronics, Inc. •...... ... •..
Rockbar Corporation • .... .. . . . .. . .. .
Sansui Electric Co .• Ltd ..... .. . . . .....
Sar kes Tarzian, Inc . •. . .. .... .. ... . . .
Schober Organ Corp. . .. . .. . .........
Scott, H. H., Inc . . .. . . . .. .. . .........
Scott Radio Laboratories. Inc. . ..... ...
Sherwood Electron ic Laboratories, Inc. ..
,Shure Brothers, Inc. ... . .. . ....... . ..
' Sonotone Corp. . . ... . . . . . ....... . ..•
Superscope, Inc. . . . ... ... . . . . . . .... .
II
63
81
87
62
27
78
79
6
75
51
1
69
4
35
United Stereo Tapes .. . . .. .. ......... 66
University Loudspeakers, Inc. . . . . . . ... 67
Address -----------.----------------------------------------------------------------------
JAMAICA
61
87
Tandberg of America, Inc. . . .... .... .. 73
Transis- Tronics, Inc . . ... .. . .. . . . Cov. IV
Tung-Sol Electric Inc. .. . ....... . ..... 65
Name ________________________ . _________________________________ "________________________ _
LOCATIONS
55
11
49
Neat Onkyo Denki Co., Ltd. .. .. ... .. .. 2
North American Phili ps Co., Inc. • . . .. .. 15
Multiplex Output. for New Stereo FM
Armstrong Circuit with Dual limiters and Foster·
Seeley Discriminator
• Extreme Sensitivity and Wide Frequency Response
• Easy-la-Assemble Kit Form
Separate FM and AM tuning sections, each with its
magic eye. FM: automatic frequency control, 2 micro'
volts sensitivity for 30 db quieting, frequency response
20-20,000 cps ±!h db , full 200 kc bandwidth. AM:
efficient broadband cirCUitry, built-in antenna. Two
printed circuit boards make wiring simple. 13¥4 XlOY.x
4'12". Shpg. wI. , 22 Ibs.
aJL... :R..A.:J> X
87
84
Marantz .. ....... . .. . . .. .. .... .... . 87
Movic Company, Inc . ... . . .. ... . . •. . . 78
•
•
Dept,' AB-1
45
Lafayette Radio . . .. . . .. . .. .... .. . .. . 88
Langevin, a Division of Sonotec
Incorporated ......... .. ....... .. . 14
Lansing, James B., Sound, Inc. . .. ..... 57
Down
Lafayette
86
39
76
31
Key Electronics Co. . ... .. ............
Kierulff Sound Corporation .. .... . . .. .
KLH Research (,0 Development Corporation
Klipsch and Associates , .. . . . . . . .... . .
STEREO TUNER KIT
74.50
37
Jensen Manufacturing Company ..... . . 41
• Rated at 50-Watts per Channel
• Response from 2·100,000 cps, 0, ·1 db at 1·Watt
• Grain Oriented, Silicon Steel lransformers
• Multiple Feedback loop Design
• Easy-lo·Assemble Kit Form
A new "laboratory Standard" dual 50-watt amplifier
guaranteed to outperform any basic stereo amplifier
on the market. Advanced engineering techniques plus
the finest components ensure flawless performance .
Distortion levels so low they are unmeasurable. Hum
and noise better than 90 db below 50-watts. Complete
with metal enclosure. 91/4 X12lf2 " D. Shpg. wI., 60 Ibs.
-SOO,A FM-
Acoustic Research, Inc. . . . .. •. . . .....
Allied Radio Corp . . . . . ..... .... . . 77 ,
Altec Lansing Corporation ......... 10,
Amperex Electronic Corp . . ..... .. .....
Ampex Audio Company .. ..... . .. . 30,
Ampex Professional Products Company ..
Apparatus Development Co. . .. . .......
Audio Bookshelf .. . .... .. ......... . .
Audio Devices, Inc. .... .. . . ... .• .. . . .
Audio Dynamics Corporation . ... ..... .
Audio Empire .... . .. .. . ... ... ... . . ..
Audio Fidelity Records ...... . ........
Audio Unlimited .. . . .. . ........... ..
NEWARK 2, N.J.
BOSTON 10, MASS
Viking of Minneapolis . ..... . .... Cov. III
Weathers I ndustries, A Division of
Advances I ndustries, Inc. ... . ..... . • 64
AUDIO
. ' F·EBRUARY, .19bl
tape your
stereo
wherever
you go
with ...
Viking qualitya1}d portability, too
, I
Viking stereo recording quality now goes portable!
The Stereo "Super-Pro" combines the famed Viking 85' deck
with dual RP62C Recording/ Playback Amplifiers. Permits remote
recording of half or quarter-track tapes with no compromise in
performance.
Your music system provides playback amplification and speakers.
Front panel contains dual microphone jacks, connectors for
headphone monitoring and high-level inputs for recording from
your music system as well.
Rugged and handsome, the "Super-Pro" is packaged in heavyduty case, covered in brown, scuff-resistant plastic with heavily
reinforced corners.
The Viking Stereo "Super-Pro" is available at authorized Viking
high fidelity dealers everywhere.
, ng
'<---+-I-'I...............,.:3IL{I"
,
'rl----1I-t--t-+z' 9600 Aldrich
OF
MINNEAPOLIS, INC .
Avenue South, Minneapolis 20. Minnesota
The Viking Stereo "Super-Pro"
Half·track or quarter·tra ck recordi ng models.
A udioph ile n et $344.50 to $379.50 dependi ng on head comple m ent.
The TEe S-15 all transistor 40 watt stereo amplifier brings a space age concept to high fidelity. Never before has the audiophile been able
to get so much high quality sound for so little . A neat package 10" long and seven pounds light puts out 40 watts of pure undistorted sound .
And the price is as exciting as the package-only $129 .50. Because of its all ·transistor ·circuitry, the unique S-15 has no heat, no hum , no
.
micro phonics. Quite naturally, from Transis·Tronics. Write for your copy of complete specifications . Power Output 40 watts (20 watts per
. .;
channel). Frequency Response ± .0.5 db 20-20,000 cps. Response is 3 db down at 6 cps and 45,000 cps. Intermodulation Distortion less
than 0.9% at rated output, 60 and 6000 cps. Harmonic Distortion less than -0 .5% at rated ·Ievels. Inputs 5 pair : magnetic phono, tuner,
tape, auxiliary I , auxiliary 2. Front Panel Controls: volume, .
channel A; treble channel 8 ; function (phono, tuner, tape,
loudness; scratch filter, rumble filter. Balance Control for
cut off sound from either speaker. Circuitry, 2 germanium
volts AC, 50-60 cps; 12-28 volts DC for battery operation .
--.J''___ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _f..;:,
EC;,..;.;.
" ....
fH..;:,E....
' .....
AO..;:,..
EMA.K
·power; balance; bass channel A; bass channel B; treble
TEC
.
.
'
1
:5' .
S
0' f.A"'''·'.O"'C,. '"c.
' aUXiliary I, auxiliary 2); mode (mono A, stereo, mono B) ;
•
,
equalizing speaker outputs. At full rotation will completely
diodes, 3 silicon diodes. Power Requirements 105-120
TEC Transistor Engineered Components
I
eI
Trallsis-Tronics, Inc., 1601 Olympic Boulevar~, S~ nta Monica , California
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