Audio Magazine February 1961

I ~ ' - , - 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 with cooler operation and better acoustic NEW 100-MA HEATER TUBE COMPLEMENTS heat-longer life expectancy-high operating response); lessens possibility of cabinet 5-Tube Radio Complement 18FX6, IRFW6. 18FY6. 34GDS. and efficiency! warping or discoloration; allows wider 36AM3-A. Performa nce equals ISO-MA Now you can design these sales advantages choice of cabinet materials; and lends new heater lube complemenlS' Yet 100-MA flexibility to positioning of parts and printed­ complement dissipates much less heat. into ac-dc home radio and stereo, thanks to 4-Tube Economy Radio Complement a new series of RCA tube complements de­ circuit boards. And important to you-these 18FX6, 20EQ7, SOFKS. 36AM3·A. To p veloped for 120-volts, 1 DO-milliampere 100-milliampere heater tube complements performance for a 4-tube complement. series-heater operation. These are the first provide performance equal to that of a 150- 2-Tube Stereo Complement Two 60FXS's can provide 1.3 watts out­ kits of 1DO-milliampere tubes whose heater milliampere heater tube complement; put per channel using a I,igh-outpul voltages add up to 120 volts, the normal furthermore little or no modification is re­ stereo cartridge. value of power supply that RCA considers quired in your basic circuit design. 3-Tube Stereo Complement 20EZ7, two SOFK S's. 20EZ7 permits usc available in most American homes. Get full details on these new 100-milli­ of stereo cartridges w ith moderate output. With these new tube kits, temperature of ampere heater tubes! Check with your RCA 4-Tube Stereo Complement cabinet hot-spots has been cut 15-25 %. This Field Representative, or write: Commercial 36AM3-A, 20EZ7, two 34GDS's. Capa· ble of delivering 1.4 watts per channel decrease in temperature permits reduction Engineering, RCA Electron Tube Division, with a B+ supply voltage of 110 volts. of cabinet size (or retention of present size Harrison, N. J. RCA FIELD OFFIC ES EA ST : 744 Brood St., Newark 2, N. J . HU 5-3900. MIDW EST: Su;te 1154, Me r· chandise Mart Plaza, Ch icago 54, Illinois, WH 4-2900. WEST: 6355 East Wash;ngton ..Th, Mo" T,.."d N,m, in EI,"mni£, Blvd. , los Angeles 22, coni. RA 3·8361. RADIO CORPORATION OF AMERICA

® 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 SOUND R1: PRODUCTION

C. G. McProud, Editor and Publisher Henry A. Schober, Business Manager $.2200 - $·3000 m - Sherwood tuners have consistently won outstanding honors from David Saslaw, Managing Editor most recognized testing organizations. They Janet M. Durgin, Production Manager feature 0.9!\Uv sensitivity, Interchannel Hush noise muting system, "Acro·Beam" tuning Edgar E. Newman, Circulation Director eye. cascode balanced input. automatic fre· quency control. and on the S·3000 m. "Iocal­ distant" switch, "Corrective" inverse feedback.

5·5000 II-' 'The Sherwood S·5000 •.. shows no Sanford L. Cahn, Advertising Director compromise or corner·cutting in design or construction."-HIGH FIDELITY MAGAZINE. West Coast Representative- The Sherwood S-5000 was highest rated by the lames C. Galloway American Audio Institute (and other testing 6535 Wilshire Boulevard, Los Angeles 48, Calif. agencies) . . . now even better. the S·5000 II has 80 watts music power, scratch and rum· Midwestern Representative- ble filter effective on all inputs. Plus Single/ Dual Bass and Treble Controls. Mid·Range Bill Pattis ~ Associates Presence Rise. Stereo·Mono Function Indicator 6316 N. Lincoln Ave., Chicagl!- 45, Ill. Lights. Phase·Reverse Switch, and Damping Factor Selector. 5·5500-Same as 5·5000 n except 50 watts CONTENTS music power, no presence rise. $159.50. Audioclinic-Jo seph Giovanelli 2 New modular component furniture-The serio Letters 6 ous hi·fi enthusiast will appreciate Sherwood's Light Listening-Chestet· Santon 8 new cabinetry in fine hand-rubbed walnut. Sherwood also makes FM Multiplex Adapters Audio ETC-E dw(M'd Tatnall Canby 12 and Crossover Networks as well as these out· Editor's Review ...... 16 standing Monophonic units: S·2000 n FM/ AM Tuner $145 .00 . S·1000 IT "Music Center" A Case for the Custom Console-F. H. J ac kson 18 Amplifier·Preamp. 36 watts $109.50. "Ersatz Stereo" Unlimited-C. H. lJilalmstedt 20 Sherwood Electronic Laboratories. Inc., 4300 Computers in Audio Design-R. G. B uscher-In Two Pa1·ts-Pa1·t One 22 N. California Ave •• Chicago 18, Illinois. Characteristics of Tape Noise-William B . Snow 26 Tape Guide-Understanding the Tape Oscillator-He1'man BU1'stein and H em'y C. Pollak · ...... 28 Loudspeaker Design-N01 'man H. Crowhu1'st ...... 36 Equipment Profile-Sargent-Rayment S R -8000 tune1'-p1'eamp and S R-202 Rev e rb e mti01~ unit-Shure S tudio Dynetic stet'eo m'm and cart1'idg e­ F ai1'child 440 t U 1"1~ t a bl e-H . H. S cott LT-10 FM tune1' kit- Ercona N01"Cli c loudspealcer ...... 48 Record Revue-Edwa1'd T atnall Canby ...... 60 About Music-Harold Law1'ence ...... 66 J azz and All That-Charles A. Robet·tson 68 New Products 74 Modular Component Furniture New Literature 77 Industry Notes 87 Advertising Index 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 record 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 fl exibility 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 and 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 countries, $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. for brochure write Dept. A·2 .

AUDIO • FEBRUARY, 1961 AUO IOclinic STABLE ROTATION GIVES YO U JOSEPH GIOVANELLI ';'

Head Wear the best he can do is to give yon an ap­ REAL Q. Quite otten we see tape head man1t· proximation. If one head specifies 100 hours tacfu1'e1's incl1ule among the'ir specifications of life and another one 1000 hours you an esti?nated lite tor thei1' heads. For in­ can guess with some certainty that the lat· stance, one Viking head has a ?1tini1num tel' head is a better head from the life SATISFACTION !-ite of 1000 hours acconl'ing to the com· expectancy standpoint than the former. We pany. Si?1.c e no tape speed is specified, isn't cannot know, of course, whether this ap· th'is statement incomplete?, It we think of plies to all other performance data for the the wea?'ing prope?·ties ot 1'ec01'cling tape as head. consisting of so many "gl-itS per i?fph" ot weal' at the heaels, then at 3.75 ips it' would To Play 78's take twic!:: as long to Ca1tSe a given amount Q. I have, in addition to my regular ot weal' than at 7.5 ips. I s this true, or· rec01'd collections, several dozen old 78- have I ovel'looked s01nething? Dick Dun· rpm Tecol'ds elating [l'om the early 30's. ham, Memphis, Tennessee. I am planning ·to tape the best ot these. NEAT A. The data for the life expectancy of a I wmtld like to know the best 1nethod ot Professional 4 speed turntable wi th tape playback or record head must, of ne· gett'ing them on the tape. I s it wise to play cessity, be incomplete. The manufacturer the recoTds with a l·mil or a 0.7-mil stylus cannot know the speed with which the in ordm' to get below the wont areas in the head is to be associated and hence, the num· Groove? John Wawzone7c, Cumberland, bel' of abrasive particles which will pass Rhode I sland. P':'68'H over it. Also, he do es not lmow what tape A. To begin with, I do not recommend tensions and pressures the head will be sub· that you play your old 78's with a I-mil j ected to. or a 0.7-mil stylus. Either of these styli I would say that tensions and prcs3ures will sink to the bottom of the groove and are more likely to contribnte to t he varia­ will cut into the shellac, resulting in stylus tions in head life than will the possi.ble damage and causing considerable noise in variations in tape speed. There is, of reproduction. FUI:t\ler, the narrow stylns course, no doubt that the f aster tape travel, will flop around ~: the grooves, leading to the faster the head will wear. However, I poor tracing. . am not at all sure that this wear is directly Your best bet is to use either a 3- or a 2- Specifications: propmtional to speed. As the tape speed mil stylUS. increases, there is an accompanying increase Since almost all 78's have no sound above Motor: of the n umber of abrasive particles which 6000 cps, the·re is no need for f ull fre­ 4 pole capacitor·sta,,.r:t hysteresis ' pass over the head during a given time quency response from your cartridge. Use synchronous motor. , . plus an increase of tape pressure. Obvi­ a scratch filter set somewhere between 6000 ously, this tape pressure incr ease will re­ and 9000 cps. If you have a rumble filter, Turntable : !'u!t in the head being abraded more quickly it should be set to 50 cps. This will give 12" diameter aluminum diecast· than had the pressure remained constant. you the quietest reproduction with little or (You should remember, however, that tape no deterioration of the original sound qual· ing. wear does not consist only of the rapid ity contained on the records. Quieter repro­ Speed: passage of abrasive particles over tho duction could probably be gained if more head. If these particles passed over the of the highs were to be sacrificed, but it is 16-i, 33·i, 45, 78 r.p.m. hEad with zero pressure, there would be no my personal feeling that a little noise is Power consumption: 15 watts. wear regardless of tape speed. Wear, then, not too much of a price to pay for the best i~ a combination of the abrasive quality of sound. Recommended stylus force: the tape plus the pI'essure with which this Noise in Headphones 15 gr. maximum abrasion is applied to the head.) Both of these factors must be taken into account Q. I have been bothered recently by an SjN : 45 db minimum before we can estimate the life of the head. increasing noise level t"om 1ny stereo rec· Wow and flutter : With some machines theTe may be no in­ ords, especially when played over head· crease in pressure; in othel's the pressure phones. The noise is a sputtering S01tnd, 0.25 % maximum may increase as the squal'e of the speed present only when the channels are not in Frequency: 50 cjs.-60 cjs. ratios. This depends on the kind of ten­ parallel. I t was .neg ligible in level at first, sion·maintaining apparatus the machine but has become objectionable lately. John Voltage: 90-117 volts. employs. Wawsonek, Cumberland, Rhode Island. As you can see, the manufacturer cannot A. The sputtering noise of which you bike all of this into account. Therefore, NEAT ONKYO DENKI CO., LTD. speak can have several causes. First, the No. 4·1 chome, Kand a Hi tago·cho. stylus in your cartridge may be wearing Chiyoda·ku , Tokyo , Japan * 3420 Newkil'k Ave., B"ooklyn 3, N .Y.

2 AUDIO • FEBRUARY, 1961 THE AUTOMATIC TURNTABLE MODEL 88 (MK·U) MODEL 210 LABORATORY SERIES TYPE A DELUXE RECORD CHANGER DELUXE INTERMIX CHANGER An entirely new kind of record-playing unit com· This is a new version of the famed RC88 manual Garrard's most compact automatic and manual bining all the advantages of a true dynamically player/ automatic changer combination, with every changer . . . the Model 210 is noteworthy for its ..... balanced tone arm , a full·size professional turn­ key feature already proven through years of unsur­ versatility. It is sca led to fit any cabinet designed ...c table, plus the convenience of the world's finest passed performance . .. millions of playing hours for a record changer. It plays and intermixes rec­ CI :;: automatic record·handling mechanism-all in one in hundreds . of thousands of homes. Now further ords of all sizes. Though moderately priced, it is superb instrument. This unit was designed to refined to provide even better performance, the a Garrard in every respect, precision built to appeal to the most critical and knowledgeable, new RC88 still offers the exclusive pusher platform Garrard's highest standards, suitable for the finest with performance so outstanding that it even sur· which made its predece ssor the be st selling unit stereo and mono music systems; ideal for replac· passes the professional turntable standards estab· in the entire high fidelity component field. ing obsolete record changers. lished by NARTB. (Less cartridge) $69. 50. (Less cartridge) $59. 50. (Less cartridge) $44.50.

~ The only dynamically balanced tone arm on Full manual pOSition : The RCBa Is a single record " Slide/slide" controls-Select manual (single play) - ~ an automatic unit. .. with adjustable slid­ player as well as an automatic changer. At the ~ or automatic operation on separate hal ves of the ing counterweight, and built·in calibrated scale to set and in· ;:::::::::.'~ \ touch of a switch, the tone arm is freed, and ~~ unitized panel. Instantly the 210 is ready to play. sure correct stylus tracking force. Once balanced, this arm will ~ individual records (or bands) are played by hand. Clearest, simplest controls on any reco rd changer! track ste reo grooves perfectl~ with pre cise specified pressure. ~ The exclusive Garrard pusher platform-remains the Full-sized, heavily weighted (6 lb.). Actually 2 turn­ GARRARD's 4-pole shaded "'nduction Surge n motor only automatic device that Insures positive, gentle ~ tables ••. a drive table inside, a non-ferrous heavy with rotor dynamically balanced-a refinement not handling of all records, rega rdless of diameter or .,.,..~ ... ~ cast table outside; with a vibration·damping reSili­ found in other record changers in this class. '"c: condition of center hole, or the record surface ent foam ba rrier. Insures constant speed with no hum or vibration. ....= at ~ or edges . ~ ~ New exclusive, completely shielded 4·pole shaded ... Interchangeable spindles (manual and automatic). ' Extra.sensitive stylus pressure control through in· Laboratory Series Motor .•. developed by Garrard >- Have no moving parts to ni ck or enlarge record • stantly accessible knurled knob built into the cast .~ especially for the Type A tUrntable system. Insures center holes. Records are lifted from turntable \ \~ aluminum tone arm, insures preci se speCified cor- true mu sical pitch, clear sustained passages with­ ~ 0 without Interference, with spindle removed. ~ rect tracking pressure at all times. out wow, flutter, or magnetic hum. ~ ~ The great plus feature of automatic play-without Exclusive cast·alumlnum, true·tangent tone arm The Ideal Garrard changer to replace obsolete compromise. Garrard's exclusive pusher platform provid es rigi dity . low resonance , low mass . light equipment in existing cabinets. Every part is changing mechanism, makes the Type A fully auto· weight interchangeable plug·in heads accommodate built to Garra rd's highest standards, yet it is so ~ matic, at your option. Convenient, reliable, maxi· cartridges of any make . ~ ~ compact it will fit any record changer cabinet mum protection for records. kt\ , You will enjoy a ~~~1 Write for your Garrard Comparator Guide, Dept. GB-ll, Garrard Sales Corp., Port Washington, N. Y. ~.~ II world's finest for its precision J... its performance .•. its convenience •. 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 micro­ phonics. 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 pre­ \ amplifier disconnected from the power am­ plifier, it is almost certain that this noise i~ generated within the power amplifier and J that the sensitivity of the phones is allow­ ing 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 di­ rectly 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. It's the ?~e~() 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 Sonotone Ceramic ('Velocitone" figure out something else. No stereo cartridge-not even the finest FM "drift"? Q. My FM tuner, which does not have magnetic in the world -outperforms it! a metal cover, is located in close proxi1nity to othe7' equipment. I am troubled by the fact that sometimes Listen! , . with your own magnetic ... or with any magnetic you can buy when I walk into the room containing the today-at any price. Then replace it directly in your component tuner, it suddenly goes out of tune. The system with Sonotone's new "VELOCITONE" STEREO CERAMIC degree of this is determined by my posi. CARTRIDGE ASSEMBLY. Listen again! We challenge you to tell tion in the room. Can you explain this phe­ the difference. Experts have tried ... in dozens of A-B listening nomenon and suggest a remedy? Martin tests. And, in every single one, Sonotone's "VELOCITONE" per­ Hack, Kew Gardens, New York. formed as well as or better than the world's best magnetic. A. The f act that your tuner does not have a cover has nothing to do with con­ Listen! , . perfectly flat response in the extreme highs and lows (better dition of instability you have noted. What ' , than many of the largest-selling magnetics). you are experiencing is not a matter of a L1sten. " excellent channel separation-sharp, crisp definition. . change in turning with certain positions · , you occupy in the room, but has to do with L ~sten . , . highest compliance - considerably superior tracking ability. changing signal strengths. ' , I would guess that you are using an in­ L ~sten , , , absolutely no magnetic hum - quick, easy, direct attachment door antenna in association with this re­ ' , to any magnetic inputs. . ceiver. Raise this antenna to ceiling height L ~sten" and place it in a spot where room traffic , remarkable performance characteristics unexcelled anyWhere, is at a minimum. If the final position of (Write Sonotone Corporation for specifications.) the antenna is near a window, enough sig­ Now listen to the price. Only $23.50 Hst ... about half the price nal strength to saturate the limiters will of a good stereo magnetic cartri.dge. Yet Sonotone's probably be gained. Once this has been ac­ complished, you probably can walk all over "VELOCITONE" stereo ceramic car- - the room without noticing these unwanted tridge system cannot be outper­ signal changes. formed by any magnetic-regardless of price. Three-W·ay Speaker System Balance Q. I s there not some more exact method of setting the level controls of a 3 speaker Sonotone"! sound system than just utilizing the way it sounds to the individ~tal? I have a stereo ELECTRONIC APPLICATIONS DIVISION, ELMSFORD, N. Y., DEPT. C26-21 sound S1.Jstern terminating in two sets of IN CANADA, CONTACT ATLAS RADIO CORP., LTD., TORONTO LEADING MAKERS OF CARTRIDGES' SPEAKERS' TA PE HEADS' MIKES' ELECTRONIC TUBES' BATTERIES (Continued on page 82)

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 de­ signed 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 inter­ com installations. Ask your Belden Electron­ ics Distributor for complete specifications.

Microphone and Shielded Power Supply Cables Miniature Broadcast Audio Cable

8410 ~~_ 8411

8413 8420 Two Conductor Shielded Cable

8739 =~~~~= 8761 Three Conductor Shielded Cable

8731 Belden Multiple Pair Individu­ ally Sh ielded Cables use Hp:;f] Beldfoil*. a Belden develop­ ment and a major break­ through in the search for quiet cables.

Multiple Pair 8767 Unshielded Cable •• 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 LETTERS Mystery of the xx's The last formula on the page should read

~nly s mall qV 1 _ 10 V org an with SIR : two full tl, =k l ' X 4N1 - "Jii' 61-note key· Just a line to thank you for the accurat e boards and and f ull review of the Patrician 700 and 22 stops. I am also puzzled by the a utho r '~ high· Re qu ir es only Stereon 200 loudspeakers in your J anua ry 2'x3'2" floo r frequency corrections at t he ceramIC and s pace ! Com­ issue. . . high-level inputs. H e states that R,c.= 7 m e rcia l value a ppro ximate­ One unfortunate point of the reVIew IS microseconds ; and thus he get s. C = 10 lillCO ­ ly 51600 that page 40 has a paragraph treating ou or more . f arads for R, = 680,000 ohms. Slllce 7 mIcro­ the size of the P atrician but unfortunately seconds corresponds to about 23,000 cps, I the measnrements were never entered be· f ail to see a reason for making R.G = '7 fore going to press. We hop ~ you can do microseconds. somet hing t o indicate that tIns apparently D ON G. DAUGHERTY, dimensionless speaker actually does hayc 6E University Houseg. physical properties as well as ethereal ones. Madison 5, Wisconsin We want to ensure that your readers never ( We ag1'ee t hat 23,000 cps seems like too confuse the P atrician 700 with t he book­ high a f1'e quency to compensate for, and shelf models. we have a sked Mr. Bosselam' f01' f1Lrtli er T ER,ENCE E. F UREY, comment. ED. ) Manager, Consumer P roducts, Electro-Voice, Inc., More XX's Buchanan, Michigan. ( How 1'ig h t ! C1Lst01n is t o use xx's in­ (It seems as though our fingm' got stuck st ead of some infonnation not iflnmediately on the "X" key during the preparatton of BUILD THIS SUPERB at hand. P1'ope1' additional C1Lst011t is . to t he ,Tanuan / 'iss'ue . On page 54, thi1'd co l· fill in the ,appropriate fig ures befo-;e pnnt­ Wlnn, 'fifth -line t hey appea1' again. Please ing. H erewith the con'ected paragraph tor C1'OSS th el1~ onto That's why they, m'e ,there the page 40 omissions : any71OW--1.Ve, tried to aross O1Lt something ORGAN "The complete Patrician 700 is not small else. ED. ) by any means-obviously .a ny ~n clos ~ r~ which can accommodate a 30-111. cone R.everberation speaker must be large. But the performance FROM SIMPLE KITS is also "big." The cabinet itself measures SIR : Will you please advise me or print .an 54V2 in. high, -33 in. across the front, and article in regard to the new rever beratlOll 28% in. from f ront to back. , The rear units ~ corners are cut off , and the cabinet is in­ I am starting to convert a rather la rge ani save ove,50% tI:nded to be positioned in' a corner with the cutoff corners 6 in. from the walls. system to stereo and do not wa nt to slip Give Your Family A Lifetime up on any possibility. I happen to be a Thus the front is 44 in. f rom the actual of Musical Joy With A Magnificent earner of the r oom, measured on the line pipe or O' an fan, and it would certainly Schober Electronic Organ! bisecting t he corner." seem th:t of all music t his type ,yould be And we do not have any constnwtion helped most by such an addition-a rever­ Now you can build the brilliant, full­ beration uni t, t hat is. range Schober CONSOLETTE or the plans f01' it . ED. ) larger CONCERT MODEL with simple G. W. McELHINNY, hand t ools ! No skills a re needed; no wood­ More Gremlins 603 Sheth Avenue, working n ecessary. JUst assemble clearly Havre, Montanqa marked electronic pa r ts guided by step­ Sm: (See EQUIPMENT PROF ILE, page 48 this by-step instructions. You build from kits, I have found Mr. Bosselaers' article, issue, for S01M information on the newer as fast or as slowly as you please ... at "Designing a transistorized preamp," 1'everberation units. A mm'e c01nplefie m·tt­ home in your spare time - with a small (J anuary, 1961), both interesting and in­ cle is scl! eel'uled f01' the April issue; ED. ) table 'serving as your entire work shop. formative. However, there appear to be Pay As You Build! sever al errors which need correction. They Editorial Needs are as follows : Start building your organ a t once, invest ­ SIR: ing just $18.94! The superb instrument Page 26, third column- As a regular subscriber of AUDIO, I do you assemble is as fine, a nd technically not remember seeing an article on the can· perfect, as a commercial organ . . . yet / 10 V /10 V you save over 50% on quality electronic N =\J el/ should read N =\J T struction of a Hi-Fi TV tuner for the parts, high-priced labor, usual store so und cha nnel only. mar k-up! Rs = (N - l) 1' e= (N- l )(2/1e) should read Of course, most of us t ake t he so und off Free Booklet R, = ( N -l)r e= (N - 1) (26/ 1e) the TV set. I would like to build a separate Send for 16-page booklet in full color tuner for TV, since there are many pro­ R .• + I ex 100 ?ll-1i = 680 + 52 x 100 mv = 3-3 mv g rams I listen to rather than wat ch (for describing Schober organs you may build 2200 2200 f.or home, church or school - plus a r ticles example, the Bell Telephone Hour) . R.: +1'0 on how easy it is to build should read 2200 x 100 111V = etc. Can yo u provide me with a const ruction your c'vn organ and how article if there is one. If not, perhaps you pleasar,t it is to learn to THE GREAT can make suggestions and furnish a block play. Also available is CONCERT T GR , + 120 11l V = 460 mv should read 10" LP demonstration diagram for such a unit. My thought is to MODEL I eR, + 120 mv = 460 mv. lise a TV t Ull er unit, change the oscillator record (price $2.00 - re­ meets fundable on first order) . specifications of R , = 6.6 R, should read R, =6 .6 R, coils and bring the i.f. to 10.7 mc, and Send for literature. No Ame rican feeding it into the FM tuner i.f. st!·ip. The . obligation and no sales­ Guild of Resistors should have been marked on the other possibility is to use the F M tuner as m a n will call. Organists drawing in Fig. 3. R, is 56k and R. is 9100 an 88-mc i.f. amplifier. in base circuit of upper left transistor. MOR'l'ON J. S AVADA, Mail This Coupon For FREE Schober Literature fl.. is 680·ohm resistor in emitter circujt. And Hi-Fi Demonstration Record TODAY! Sunny Ridge Rd., R; is 68 0k resistor from ceramic input. Ca­ H arrison, N. Y . pacitor values associated with the ceramic ------.The Schober Organ Corp., Dept. AE-5 I (Like most inventions, t he problem is pmc­ 43 West 615t St., Ne w York 23, N. Y. input and wit h the two high· level inputs t-ieally solved when t he need is eletennined. should be i u micro·microfarads (pico­ o P lease send me the 10" hl-U Schober I T he T V t1Lner f eeding into an i.f . strip­ Il nd other literature on the Schober organs. I farads) instead of in farads as shown . and why not use a 21-mc i.f.?- is a f airly P age 62, second column- o Please send me the 10" hl-U Schober simple solution. The 88'1JW i.f. is likely to demonstration record. I enclose $2.00 (re- I In the second line, the equation should read fundable on receipt or my first kit order). I eQ1LSe t1·DtLble with two high·f 1·equency os­ - 1) 36,000 = 684,000 eillatm's in 'til e same room . We WDtL ld wel­ Name ...... I ( 0.1~ come a constrllction article on this item, fC; I In the appe:ldix, even th01Lg h t he elemand f01' 8'1w h a t1L'/Ler is appm'ently not g1'e at-at least two have . I 7cT (m cos wt-14 nt' cos 2:JJt) been 01!e1'ecl commercially built, but none ___ -.;~ . ~~ . ~= . ~~t~ . ~ ;...... should be divided by "q". scems to be at the p1·esent. ED. )

6 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~~: :1-··. -::_~ " 'i.._ _ ~;;. pi.! at your authorized Pilot dealer. Both are U.L.-Iisted. Write for literature to: iI 9 _e ._ ;- - .";- :: Gr:; §~~ e . Pllor Radio Corporation, 37-38 36th Street, Long Island City 1, N. Y. ; ..~ _:2-;:;:;, # .,~ , I"OUNOED 1 81 9 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 ses­ sion-the voice appears to originate in an area several inches in front of as welL.. as._beh indo the loudspeakers.

George Wright Encores Hi Fi Tape 0 R 702 George Wright Encores (Vol. 2) Hi Fi Records R 711 Let the beginner demonstrate to his unsus­ pecting 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 invest­ ment required these days for really good bass reproduction. I dig out this recent pair of The Unsinkable Molly Brown (Original releases by Georgie Wright. The first , a stereo The symbol indicates the United tape; the other, a mono disc of similar elec­ 0 Broadway Cast) tions. If the comparison is confined to fre­ Stereo Tapes 4-track 7 Vz ips tape Capitol SWAO 1509 quency response, a good mono disc and a four­ number. Andre Kostelanetz: Unsinkable Molly track tape are a reasonably fair match. Both can operate in the region of the pedal notes Brown on almost equal terms. Assuming that your Columbia CS 8376 Tenderloin (Original Broadway Cast) amplifiers and speakers can deliver substan­ tial output at 30 cps, the comparison is quite Capitol SWAO 1492 You may detect traces of more than one rags-to-riches play in this saga of a mining instructive. Boasting an album number that should be town tomboy and her struggle to attain accept­ Start with the mono disc and the bass a cinch to remember, this Capitol recording ance in Denver society. The line that best sounds pleasingly plump--until you switch deploys the season's first major Broadway sums up her humble beginnings occurs In the over to the tape. Then the pedal notes feel musical. The lull that has separated the end program notes describing the start of Act I. like the real thing. The difference is explained of the '59 season and the resumption of ac­ It's a sentence that struck me as a new and when you go back to the disc. Then what first tivity in the Fall of 1960 demonstrates more delicious model f"or musicals of this type, "As seemed like authentic and robust bass is than ever the importance of the musical stage the curtain rises, Molly and her brothers are shown up for what it really is. The funda­ in the plans, of the record industry. Even on rasslln' in front of their tumbledown shack mentals are on the tape. The disc, in Its low records, Tenderloin underlines the importance in Hannibal, Missouri." Once that business end response is merely pumping strengthened of theatrical know-h'ow that only a n experi­ is out of the way, accompanied by Meredith harmonics. Despite the fact that a mono enced production team can bring to a show. Willson's marches and saloon songs, Molly groove can accommodate wider excursions with The producers, Robert Griffith and Harold proceeds to fight her way up every ladder in less risk of overcutting than a stereo disc, Prince, have already given Broadway such sight. She walks from Hannibal to the mining even this somewhat better-than-average mono outstanding attractions as "Pajama Game," town of Leadville, Colorado. After a brief HI Fi record cannot match the tape's bass re­ "Damn Yankees," "West Side Story" and most career as a saloon entertainer with a one­ sponse. George Wright, in novelties or stand­ recently, "Fiorello." In tbelr latest effort, song repertory, she marries Leadville Johnny a rds, is one of the very few organists with which stars Maurice Evans in a singing role Brown who soon becomes the wealthiest miner sufficient technique to encourage repeated as a crusading minister, they reaffirm their in Colorado. Her saucy struggles in Denver listening and his roster of tunes in each of faith in New York City as the plot center of and European society take up the rest of the these releases is tops in diversity and show· their theatrical universe. This time t hey zero plot. Her refusal to sink with the Titanic ex­ manship. in on t he area known as the Tenderloin in the plains the title of the show. 1890's- the favorite district of police cap­ Tammy Grimes, in her juiciest role so far, tains, tabloids, and the more versatile funsters carries most of the show with such tunes as Felicia Sanders: Songs of Kurt Weill in the male population. I Ai n't Down Yet, Beny Up To The Bar Boys, Time 0 ST 2007 Some seven years ago, the producers began and Beautiful People of D enver. Yet Miss to plan a musical based on the famous anti­ Grimes would be the first to admit that her Time is one of the newer labels that Tenderloin crusade of the Rev. Dr. Charles leading man, Harve Presnell, carries off top wouldn't be caught dead in the market place Parkhurst. The appearance of a Samuel Hop­ vocal honors in his fiL'St Broadway show. The with a gimmick-free recording. Knowing they kins Adams book on the subject two years 26-year old Californian should have no diffi­ were ardent proponents of ping-pongery, I ago got the ball rolling in earnest. The entire culty establlshing a solid career on Broadway had to suppress a qualm or two when I opened "Fiorello" team-director George Abbott and in view of the rich flexibility he brings to his this tape reel containing show songs of t he his co-author J erome Weidman, composer three main songs. I'll Neve,' Say No and the great Kurt Weill that have long deserved Jerry Bock, a nd lyricist Sheldon Harnick­ Enropean-flavored Dolce Fa,' Niente hold wider circulation. Surely they weren't plan­ went to work on this show a week after promise of the most frequent performance ning to toss the voice of Felicia Sanders from "Fiorello" opened In November, 1959. The ou tside of the Winter Garden Theatre. channel to channel. I was relieved to discover rowdiness of the local color is best depicted Hard on the heels of auy major musical t hat the major departure from normal proce­ in the choral numbers by the Tenderloin these days comes a batch of "cover" albums, dure rested in the rather exotic reasoning out­ crowd. Little Old New Yo-rk and How the non-cast recordings that use the score for lined in the album notes that attempted to Moncy Changes Hands are gas-lit endorsements t heir own purposes. The Kostelanetz instru­ explain their placement of voice, rhythm sec­ of the status quo. The two best ballads in mental version was early at the starting gate tion, and brass in the left channel-strings the score are Art'ijicial Flower8 and the haunt­ with eleven "Molly" tunes selected for their and woodwinds in t he right. The first eyebrow ing lJIy Gentle Young Johnny. The first is a buoyancy in orchestral garb. His arrangers lifter was this sentence in the liner notes. standard t ear jerker but J ohnny, as sung by have had to struggle with a situation that "There is so much musical logic in recording Eileen Rodgers, has the appeal of the t rue other slick orchestras will face. The home­ a vocalist in this fashion that one wonders folk ballad. Maurice Evans reveals a service­ spun sections of the score don't come over why no one realized it until Time's experi­ able voice fully up to the demands of his cru­ with very much conviction. Columbia'S Rtereo ments led the engineers to the inescapable sade. Those who know him solely in Shake­ gives a wide frontage to the orchestra's sound conclusion that this was the way to do it." spearean roles may be surprised to learn that with good pinpointing of the violin and cello My reaction was immediate. In fairness to this is his second Singing role in the theatre. sections. other labels, it should be pointed out that Capitol's stereo sound in this album rates this technique is hardly new with Time. I a special word. Their miking theory in past happen to have in my collection of stereo show albums has aimed at spaciousness Margaret Whiting Sings the Jerome discs a recording called "Ruth Brown Late achieved in the Simplest fashion. Instead of Kern Songbook Date" (Atlantic 8-1308). That disc is at least resorting to reverb units for illusion of thea­ Verve VSTP 243 a year and a half in age yet it places the tre liveness, they have been soalring up a 0 vocalist in the left channel and most of the maximum quota of room acoustics by the sim­ If your budget allows only fifteen t ape~ a orchestra in the right. ple expedient of refUSing to crowd their per­ year-make this one of them! It could be that The other unusual claim on the jacket lends formers. Compare this recording with the only another reviewer exposed to an average itself to more discussion. Some recording en­ original cast production of "Music Man" a nd year's recordings would join me in such a gineers are sure to question Time's implica­ you'll note the same effective use of lively glowing estimate. Everything about this PI'oj­ tion that center placement of the singer in surroundings. The "Tenderloin" recording en­ ect is top drawer. Within the tape equivalent stereo inevitably leads to blurred reproduc­ joys darn near 30 per cent increase in r e­ of two record albums are definitive vocal styl­ tion. Even more difficult to fathom is the state­ corded level a nd a decided improvement in ings of some of the greatest J erome Kern hits. ment that placement of a vocal soloist in one frequency response. This release should return Margaret Wlliting channel means-in their own words-that to the popularity she enjoyed when her version "The voice does not come from the four walls of Moonlight in Vermont was in the limelight. and merge at some central pOint. "Given con­ * 12 Forest Ave., Hast'ings-on-Hudson, Only a naturally poised voice with genuine ditions sufficiently e .."aggerated, central place­ N ew York. polish can do justice to songs sucll as Smoke ment-or any placement fo r that matter-can

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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 Sanders will r eveal miking difficulties quite unrelated to those outlined in Time's album notes. The mike selected for h!lr u se, however effective it may have been in bright­ ening percussion sou nd in other releases, is merciless in its handling of sibilants 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. Rep­ resented here are such shows as "Johnny Johnson," his first American pr.oduction, with its fl avor of the European musIc halls of the Twenties. The highlights of Weill's flfteen­ year career in this country are covered by the­ great 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. re­ cording of Weill instrumentals entitled "Speak Low." Jose Melis at Midnight/ Many Moods of Melis Seeco 0 SEP 301 Those viewers of the Jacl{ Paar show who have felt that the piano a nd orchestra of Jose Melis are not prominent enough in Ule . proceElding~, llave a (' b ~nce to indulge them­ se!,vr,es.) 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 proxim i ty to famous , personages. Some p ianists achieve fame on the strength of a quir k in style. Others work hard to become background pianists ~' d evoid of style. Melis belongs to neitbeffi ' grQup. With only a small assisting group in 'lOl!1e of the numbers-a full orches­ tra 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 PLATE SUPPLY TRANSFORMERS, 3-PHASE, 60 CYCLE DRY TYPES, a nd the cboice of tunes unhackneyed. rated from 7.5 to 250 KVA for Class A or B operation. A Journey into Stereo Sound , London 0 LPM 70000 Peerless 3-phase transformers of the type shown above are just one Back in June of 1958, when some of us more reason Peerless has led the industry for 25 years. Like Peerless were wondering whether the stereo disc would transformers of all types - including the specialized miniatures pio­ make the grade, London helped to resolve tbe issue with tbe release of this recording. Vir­ neered by the company-these high power plate supply transformers tually everyone with access to the best play­ meet the most demanding operating requirements. To insure best pos­ back equipment available at that time im­ mediately recognized the stereo disc version of sible flux distribution, cores are built of high quality grain-oriented this recording as the first example of impres­ silicon steel. The units exhibit high permeability and resistivity and sive frequency response in a two-channel groove. Tbe selections heard on this sampler extremely low hysteresis loss. leakage reactance, once established by were a hodge-podge of just abou t everything your application, is held to closest tolerance. Final testing covers volt­ London had in stereo at tbe time; bits of symphonys, concertos, oratorios, pops and age ratios, polarity, inductance, resistance, core loss, temperature rise documentary sounds. under full power and all other important factors. My favorite test bands featured a rehearsal sequeuce of a recording session (Ansermet leading the Suisse Romande Orchestra in These units are just one more proof that whatever your transformer Stravinsky's "Rite of Spring") and the d is­ needs, the experienced Peerless experts can fill them best. Units range t inctive sounds of a European train at its station. In tbe Stravinsky excerpt, just about from 1/1 a of a cubic inch to more than 20 cubic feet, from fractional e,' ery low voice in the orch estra was working voltages to 30,000, from 1 cycle to half a megacycle; 1,2 and 3-phase; to produce transients. In the train episode, tbe thud of t he side doors being closed was construction types covering the entire range. recorded at frequencies that were low enough to show up differences in the response of a succession of stereo cartridges coming on the Whatever your transformer needs, Peerless engineers can design to any market at that t ime. Now tbat t he same ma­ military or commercial specification and manufacture in any quantity. See terial is out on a four-track reel w itb little REM for complete standard line or write for information to Dept. A-2-PE. if any limitation in stereo separation, ade­ quate 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 @PEERLESS Columbia WS 318 In lbe course of her b:lingual traversal of ELECTRICAL PRODUCTS Broadway on the Audio Fidelity disc, Pata­ A DIVISION OF ALTEC LANSING CORPORATION <"hou works out a neat solution for the record ALTE[ buyer who would like to Own t he hit songs ~~ 6920 McKinley Avenue, Los Angeles 1, California from "Irma La Douce"-in French. Tbe show (Contimted on page 86)

10 AUDIO • FEBRUARY, 1961 The Quiet Sea and the new ADC-l Stereo Cartridge

There is a new and different kind of stereo cartridge for the ADC-l is also spontaneous and elating, but here an people with a special kind of sensitivity to the world explanation is in order. around them. It's called the ADC-l. Actually, no one factor is, nor can be responsible for Hear your favorite records played with this new pick­ the ADC-l's startling performance. The combination of up .. . Enjoy brilliant highs and thunderous lows free excellence of design plus precise craftsmanship provides of the slightest evidence of distortion. Experience subtle­ the answer. ties of timbre and tonal gradation you never suspected The ADC-l must be experienced to be enjoyed. It is were in your discs. With the ADC-l you will get the at your favorite dealers. Hear it today. same level of high fidelity sound playing after playing; COMPLIANCE: 20 x 10" ems/ dyne FREQUENCY RESPONSE: Unusually flat: plus or the ADC-l's low tracking force reduces record wear to DYNAMIC MASS: .5 milligrams minus 2 db: from 10 cps. to 20,000 cps. with use­ the vanishing point. CHANNEL SEPARATION: 30 db from 50 cps. to ful response extending well beyond 30,000 cps. The sensitive person's response to beauty in nature is 7,000 cps. STYlUS TIP RADIUS: .0006" usually spontaneous and needs no explanation. The thrill RECOMMENDED TRACKING FORCE: 1 gram or less in top quality tone arms experienced when listening to fine music reproduced by Audio Dynamics Corporation / 1677 Cody Avenue. Ridgewood '27, N . Y.

AUDIO • FEBRUARY, 1961 11 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 re­ ere. corder, not four. I'm sure that Mr. Snooze­ bury.... I ignored this killing logic and continued edward TatnaliCanby doggedly. Yes, I know it will cost somewhat more, but in a music school, you see, a TWIN-CHANNEL channel recorders. And the great American machine that will take down TWO record­ public has another big entertainment ques­ ings at once can be of invaluable help in HOME RECORDING tion to face--shall I buy stereo recording all sorts of educational situations. Take, For the life of me I can't find the back (as well as stereo playback)' What good for instance, a violin and a piano . ... issues of AUDIO, a couple of years ago, in is it for me' Is home dual-channel record­ -But Mr. Canby, I'm quite sure we which I described my experiments in home ing worth the cash ~ What can you do with really can't afford even two recorders. One recording via stereo tape, two mikes in iU will be quite enough for the present. hand. But I do remember that I dwelt for After all, though we've actually had Though I am sure the piano department a few lines on what seemed to me a quite four-track stereo playback equipment on would be glad to. . .. remarkable and unforeseen discovery, that the market for many months, it's only now -Two microphones, you see, I inter­ home amateur-type recording via two chan­ that one of the biggest of the U. S. popular rupted. Both running into one machine. nels is both wonderfully effective and as big brauds has come forth with twin-chan­ They make the same recording-I mean, tonishingly easy-far more versatile, more nel recording-no less than Web cor. And, almost the same. And with four tracks... . foolproof than one-mike, one-channel re­ if I may paraphrase, as Webcor goes, so -Four tracks' (A new idea was getting cording of the usual sort. goes the nation. Now it'll be full-page ads through.) You mean a machine that plays I put off detailed discussion at that point in Lite and the Post, pretty models on TV four different tapes' How interesting! But for the best of reasons. It was academic. with two mikes alluringly held in their I don't really think we can afford anything Few people had stereo recorders to play lovely two hands. This is it! Two-channel quite like that right now. You see, we've around with. Stereo was to listen to, and we home recording is here. Let's get on the raised only enough money for one tape­ were fully preoccupied in those days with bandwagon. I mean one recorder ... Oh dear, what DO listening problems-how to get stereo from I mean' Mr. Canby, do let me ask Mr. tape, then, soon, from disc. The market was Mr.Snoozebury Snoozebury, right here, what he thinks beginning to fill up with so-called "stereo­ about these four-t-ape machines. phonic tape recorders," but virtually all of Well ... almost. Not quite. The new I picked that up very hastily: ask him them were in plain fact mono recorders and models are coming out, but the way most whether he handles the Norelco, or the stereo players. All except for a handful of folks act you'd never know it. These words, Tandberg, or the Uher-they're all stereo imported models and a few tape decks of I'll wager, are being printed comfortably recorders, imported from ... . the Viking or Bell type that could be ac­ ahead of the boom, maybe by a year or so -Mr. Canby, Mr. Snoozebury has the quired, to choice, with dual-channel record­ as far as the well-known American small­ nicest tape recorder right here, and" I just ing equipment. town backwoods are concerned. Just ask wondered what you thought of it. (The your local dealer and see. cat, of course, had been waiting all this The Mono S'tandard This last December, for instance, an time to get out of the bag. Tae lady had ardent local lady called me up in our small every intention of buying the one she'd It was obvious that the general public town in Connecticut, she's head of the local long since decided upon. They always do.) was first going to learn about "pre-re­ music school, for advice on a new tape It's a-(pause, muffled voices in back­ corded" stereo, on tape and disc. One thing recorder. The school needed one for its ground) he says it's a Wollysack, or is it a at a time. Moreover, it was clear that the teaching and she knew I knew all about Gunnysack' And he'll give the School a then-new "stereo recorders" were actually such things. She would prefer, of course, very good price, since we do so dreadfully a familiar phenomenon, the transition a recorder that had no more than one push­ need a recorder for our work. model, and that real home recording via button, for aU control functions, and it Well, I gave up on the spot, as you can dual channels would have to wait until shouldn't cost more than, say, forty-five guess. I enthused over the Gunnysack, alias newly designed recorders came into produc­ dollars. This she implied in delicate lan­ the W ollensack, and opined that for her tion. The transition machines, originally guage without saying so exactly-I got the purposes it was an excellent buy. And intended for mono, didn't have room for idea all right. which model was it-did it play stereo' home two-channel recording's bulkier com­ This was a bit arch, on her part, for as She hadn't considered this, and acted as ponents. Only the European makers reso­ it turned out she was going to pay a lot though I were bringing up a tired subject lutely went ahead with their honest but more and already knew it; but she had to already well got rid of; so I didn't bother clumsy adaptations for full stereo record­ test me out against her local dealer, just to find out whether this was the half-track ing on mono-type models, notably the to be sure. I dutifully told her that tape mono model with lO-watt built-in power am­ Tandberg 5-2. didn't come as cheap as disc equipment and plifier, or the modification that plays stereo And so, right up to the present, the great she'd have to pay more, if she wanted a but is minus the power amplifier. As for bulk of our home tape recording has con­ really "good" machine; she replied she any thought of two-mike, dual-channel Te· tinued to operate on the well-tried mono guessed as much, since she'd asked a.t the cOTding, I mentally chalked this conversa­ standard. The machines may have been local hi fi and camera shop some twenty tion as Round One-a Total Loss. A rout. called stereophonic and they have become miles away-in fact, she added brightly, No, two-channel home recording was not more versatile in many ways, playing all she was there right now and Mr. Snooze­ here quite yet. sorts of tapes, full-track, half-track, quar­ bury, the proprietor, had showed her some Mr. Snooze bury (his real name is only ter-track, stereo, mono. But as recorders, very interesting new machines though they slightly different) evidently had never they have remained flatly mono. I suspect were, indeed, dreadfully expensive. heard of two-channel at that point. Nor that those relatively few recordists who You can picture my visions of Mr. did he know about the assorted European have acquired Norelcos, Tandbergs, Uhers, Snoozebury listening a foot or so from the imports I suggested. Nor any new Web­ or tape decks with stereo recording pre­ phone, but I manfully ploughed in and did cors or Reveres. If he did, he wasn't telling amps, have not done very much as yet in my duty. I suggested flatly that before she my lady friend. But as for the Wollensack, the way of stereo recordings via mikes. It bought anything she should consider a now there was a really fine little machine. isn't in the air-not yet. stereo recorder. . . It is, too. But now the moment has come. This sea­ Long pause. A what? .. . I didn't quite son for the first time the "average" Ameri­ hear what you said, Mr. Canby. Dreadful * * * can tape buyer is going to run into two­ telephone service .... (She's slightly deaf, I'll admit that this is a somewhat en­ channel home recording in earnest. The and never more so than when life offers hanced transcript of the original phone newly announced models, at last and in­ her new complications.) conversation. But it does represent the gist evitably, are true "stereo" recorders. Dual- --STEREO, I repeated carefully. I could of reality. If you doubt it, try your own

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FM and AM stereo tuners on one com· pact chassis. Easy·lo-assemble: prewired, prealigned RF and IF stages for AM and FM. Exclusive precision prewired EYE­ TRONIC® tuning on both AM and FM. FM TUNER Switched AFC (Automatic Frequency Con· trol). Sensitivity: l.5uv for 20db quieting. Frequency Response: 20-15,000 cps±ldb. AM TUNER Switched "wide" and " narrow" bandpass. High Q filter eliminates 10 kc whistle. Sensitivity: 3uv for l.OV output at 20db SIN ratio. Frequency Response: 20-9,000 cps ("wide"); 20-4,500 cps ("narrow"). FM·AM STEREO TUNER ST96 Kit $89.95 Includes Metal Cover and FET Wired $129.95

OF EICO STEREO. • • .. II • • • • •

BOTH AMPLIFIERS: Co.mplete stereo cen· ters plus two excellent power amplifiers. Accept, control, and amplify signals from any stereo or mono source. ST70: Cathode-coupled phase inverter cir· cuitry preceded by a direct-coupled voltage amplifier. Harmonic Distortion: less than 1 % from 25-20,000 cps witbin Idb of 70 watts. Frequency Response: ±'hdb 10- 50,000 cps. ST40: Highly stable Williamson-type power amplifiers. Harmonic Distortion: less than 1 % from 40-20,000 cps within 1 db of 40 watts. Frequency Response: ±'hdb 12- 25.000 cps.

70·WATT INTEGRATED STEREO AMPLIFIER ST70 Over 2 MilliON EICO instruments in use. Kit $94.95 Includes Metal Cover Wired $144.95 Most EICO Dealers offer budget terms. 40·WATT INTEGRATED STEREO AMPLIFIER ST40 Kit $79.95 Includes Metal Cover Wired $124.95

There's an EICO for your every stereo/mono need. Send for FREE catalog. ------q lI#1~ ,------EICO, 3300 N. Blvd ., L.I.C. I, N. Y. A·2 o Sen d free 32- page catalog & deal er's name o Send ne w 36-page ,Guidebook to ·HI-FI for which I enclose 25 ¢ for po stage & handling. Name Addre ss .. City . . Zone .. .. State.,. . _0______------Add 5% in West.

Listen to the EICO Hour, WABC-FM , N. Y. 95 .5 MC, Mon.-Fri., 7:15-8 P.M. © 1961 by EICO, 33 -00 N. Blvd ., L. i . C. I , N. Y.

AUDIO • FEBRUARY, 1961 13 local lady·prospect. I think you will have bury tIlls very minute. He's just showing head or tail of our present jungle of tape noticed, in any case, . one thing of signifi. me some new invention, is it the Wire terminology. cance. This lady would not buy home two· Brush ~ It plays jazz on picture wire, but It's not four recordings, you explain­ channel .r~c 01'd in~, but she lmew all about I don't really think, for my purposes.. . . merely four tracks on one tape. You don't tape recording itself, and was eagerly and MI'. Canbi}', I really don't like all this noisy use them all at once. You use two of them wisely ready to spend cash for it. What's jazz music ... . de yo.u~ in one direction and two the other· it works 1110re, she knows what to do with it when That would have been around ,1952 and , exactly like the old system. (That's reas· she gets it-mono·style, at least. I would not have tben dreamed of suggest,.. ~ surillg.) You run the tape through twice. Now pause to remind yourself what a ing a tape recorder to the lady. You call. Just pretend it's a regular recorder. (That's triumph of long·range education that is! imagine how far I would ha,7e got! So, in the solid approach.) Except that now you Maybe a good ten year's worth. ten more years, I'll bet, Mr. Snoozebury have two mil

14 AUDIO • FEBRUARY, 1961 -simultaneously) ,. we'll do much to help the THI S 1ST HE public get itself clear on fundamentals, ' before taking t he hoped-for plunge into GREATEST ·dual-channel home recording. Stereo, then, is a professional-type sound, dCONTINEUTAL' as purveyed via commercial recordings, n dual-channel recording is any type of reo cording via two channels, steI'eo included, 0 F THE M If you aren't going to stress true stereo, then what do you do with your home dual- ALL channel machine~ __ _ Almost any old thing, I n my somewhat randomly purposeful experimenting to date I've produced some wonderfully amusing, effective, slick, realistic, natural-sounding tapes, and most of my "technique" has been deliberately, absurdly crude, once I caught onto the fact that this is what works best, The zanier your mike positions, given the all-important duality, the trickier are the results, The medium is astonishing. It untangles the nuttiest muddles, disciplines the undisciplined, makes neatly formal rows out of helter-skelter masses of people, re­ duces the wildest mike gyrations (via wav­ ing arms) to staid immoveability, ... But let me pass onwards to several categories of zany simplicity t hat occur to me as help­ ful in dual-channel recording, though in practice they: overlap more or less continu­ ously.

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 the the tfore/co@' Two-Point close-np. Pick up your two mikes and stick them as close as possible t o two different sounds. CONTINENTAL '400' Make sure they are different. (Allow for N ew "--track level, of course-close-up sound is usually The stereo-record!ste reo-play back loud.) , exciting Put one mike three inches from a folk tape recorder singer's mouth (amateur, of course-no specifications Metropolitan Opera voice,s in this show); on the new Norelco guild-crafted by put the other a couple of lllches away fro111 CONTINENTAL '400' Philips of the the strings of a guitar. Keep them apart. Space your people five or six feet or morc (EL3536/54) provide only Netherlands apart. (And space your playback speakers an indication o/what "the great­ even f urther, for enhanced effect.) est Continental' of them all" holds in Or set up an amateur Romeo and J uliet store for the music lover, studio-recordist or (again, serious but a~ateur) on two mikes, w,ell separated, Or SIt two of your small high fideiity enthusiast who is seeking a profes- hds on two TV cushions and get 'em to sional quality stereo machine at a modest price. talk-with giggles. Ohannel A : "What's • FOUR-TRACK STEREOPHONIC RECORDING AND black ancl white and j'ead all ovej'?" Ohan­ PLAYBACK • FOUR-TRACK MONOPHONIC RECORDING nel B: "(Giggle) A l\TEWSpaper!!" The palpable fact is that the question AND PLAYBACK . THREE TAPE SPEEDS-1%, 3% AND 7% IPS on playback, is asked out of one l oud~ • COMPLETELY SELF-CONTAINED, INCLUDING DUAL RECORD­ speaker and the answer comes, across the I NG AND PLAYBACK PREAMPLIFIERS, DUAL POWER AMPLIFIERS AND room, out of the other. That is t he big new dramatic sensation. The spatial dialoguc TWO NORELCO WIDE-RANGE LOUDSPEAKERS (SECOND IN LID) each sound inside a different speaker (not • CAN ALSO BE USED AS A QUALITY STEREO HI-FI REPRO­ behind it), makes for a lively, surprisingly DUCING SYSTEM WITH TUNER OR RECORD PLAYER . engaging effect of "two-ness," much more attractive than the inflexible "one-ness" of FACILITY FOR MIXING PHONO AND MIKE INPUTS the ordinary mono recording! Just watch • HEAD-GAP WIDTH -.00012" • FREQUENCY the listening heads bob back and forth, RESPONSE-SO TO 18,000 CPS AT 7% IPS . Two-point commercial stereo is often prett y dull, ping-pong style. But in home record­ WOW AND FLUTTER-LESS THAN .15% Fora ing it's something else again. F un, effec­ AT 7% IPS • SIGNAL-TO-NOISE convincing tive, useful. RAT10-48 DB OR BETTER . demonstration Almost any sort of duet or dialog is CROSSTALK - 55 DB • of all of the features made much more interesting by this simple PORTABLE STYLED BY and qualities that home technique. Ordinary conversations make the Continental grow vivid when one person is in each THE CONTINENT'S '400' "the greatest speaker, instead of the nsual situation TOP DESIGNERS where several voices are superimposed one A Noreleo . 'Continental' of them on top of the other f or a spatial monotone. dual element • RUGGED all," visit your favm'ite stereow . hi-fi cente1', or photo dynamic dealer, or write f01' Absolute vs. Re lative 'miCr01Jhone • is standard complete litemture to: It may occur to you that t hese dual re­ equip')uent North Amerwan Philips Co.,Inc. cOl'clings made close-up and excluding vir· w ith the High Fidelity P1'oducts Division tually all liveness or room-sound, are essen· CONTINENTAL 230 Duffy Avenue, tially absolute recordings. The two t racks '400' Hicksville, L. I., N. Y. (Contin1£ed on page 58)

AUDIO • FEBRUARY, 1961 15 EDITOR'S REVIEW

THE "BEST" LOUDSPEAKER ing a lot, for there are no perfect loudspeakers. By the same token, if all manufacturers were able to make EGARDLESS OF SOURCE MATERIAL, amplifier phono loudspeakers which were perfect, then all 0'£ the prod­ pickup, tape recorder, or microphone, the last link ucts of the various manufacturers should sound alike, Rin the entire chain of any sound reproduction sys­ and everyone knows that they do not. tem is the loudspeaker. And no matter how good the Now it is to be assumed that every manufacturer rest of the equipment-including the original source strives to make a good loudspeaker-certainly the -the loudspeaker is the one element most likely to basic principles of craftsmanship as well as business introduce its own characteristics into the over-all demands that he do so. But he must also make a salable sound quality. product if he is to stay in business. And this is where Some audiofans, searching for the ultimate in a the differences come in. Those who have the responsi­ loudspeaker enclosure, take the viewpoint that sound bility of passing on the over-all sound quality of the should be reproduced by some device with "reso­ product may have different tastes, and those tastes are nance. " Their fundamental idea seems to come from certainly reflected in the speaker. The main problem the fact that a violin, for instance, has "resonance" in loudspeaker manufacture is to turn out a product and that therefore-since it is recognized as stlcn a that will appeal to a large enough segment of the good sound .. producer-a loudspeaker should be de­ listening public to make it economically successful. signed like a violin. Others choose a different ]Il!stru­ We are so often asked, "What is the best loud­ ment tid copy in order to make a loudspeaker C"lIDoinet, speaker?" or "What speaker should I buy ?" For with no better results. many reasons we cannot answer that question. First Sticking to the violin analogy, it must be recogniized and foremost is the unfairness on our part if we were that its" frequency response" is not flat thromghout to tell enquirers that the product of one of our ad­ the entire audio spectrum. Actually, it is freq'\;l!mcy vertisers was better than the product of another. If we response primarily that makes the difference between were to say that we like X's speaker (or amplifier or a fine instrument and the poorest of fiddles. Slllip>pose, tuner or phonograph cartridge or turntable or what­ for instance, that we had a violin which had a: IO-db not) Y is certainly not going to like us any more. peak in its frequency response at 1400 cps-a ]to·t im­ Neither is Z nor A nor B nor anybody except X. possible condition. Let us suppose further that we had The most important (to the speaker buyer) is the a loudspeaker built in the form of a violin just like fact that not everyone likes exactly the same type of our original so that there was a 10-db peak in the loud­ sound. And since all loudspeakers do not sound alike speaker at 1400 cps. Then we play music on the origi­ -the biggest understatement of the year so far-the 'nal instrument and reproduce it on the violin-loud­ only logical answer is for the individual to hear as speaker. We would have a resultant peak of 20 db at many as possible and then select the one that he likes 1400 cps. This is not unlike the trouble in dubbing best. To be sure this is difficult for the man who is tape after tape in a consecutive pattern-that is, copy not close to an audio salon or who must buy from ad­ 1 from the original, copy 2 from copy 1, copy 3 from vertisements alone. We feel that within the same price copy 2, copy 4 from copy 3, and so on. This is in con­ class there is not a great difference in quality. Com­ trast to the normal method in which copy 1, copy 2, mon sense tells us that it is not likely that one manu­ copy 3, and so on are all dubbed from the original. facturer can make a loudspeaker for $19.85 that is In the consecutive pattern, a 2-db peak in the system just as good as another's unit at $495.00. Our advice, anywhere would put an equivalent peak on copy 1; then, is always, "Choose the product of any reputable a 4-db peak on copy 2, a 6-db peak on copy 3, an 8-db manufacturer in the price range you want" when you peak on copy 4, and so on. This practice is not usual in can't compare a lot of them. When you can, we say, commercial dubbing, but if audiofan A makes a copy "Choose from the products of any reputable manu­ from his original tape and gives it to audiofan B, and facturer and pick the one that sounds best to you. " he copies it and gives it to C and he copies it and gives Even if we would, we could not say which loudspeaker it to D who-and so on-the frequency response of the you would like best, and anyhow you're the one who last. copy will contain all the defects of all of the re­ is going to listen to it and we don't want to "shoulder corders of the system. the blame" if you're not satisfied. Thus what is needed is a loudspeaker that is entirely And as a final word, hear as many as you can at the inert-it should not introduce any characteristics of Washington High Fidelity Show, February 10-12 at its own into the reproduction. That is, of course, ask- the Shoreham Hotel.

16 AUDI O • FEBRUARY, 196 1 An ultra-linear professional pickup for recording channel calibration, radio stations and record evaluation by engineers and cri tics ... from $48.00

Collectors Series: Model 380-A pre­ ci sion pickup for the discriminating I record collector . .. fro m $29.85

1 j

Pro-Standard Series: MK II-A pro· fes s i o nal pi c kup outs tanding for quality control . .. f rom $24.00

/

StereoPlayer Series: Stereo 90- A fi ne quality stereo magnetic pick­ up for the audiophile . . . $16.50 i Illore for everyone .... :nlore for eve~y ' applicatiOI1.

.. . so much more ·for 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 .to 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. 2,917.590

Send for Pickering' Tech-Specs-"a guide for planning a stereo high fidelity ·s'\'stelln . . . address Dept. B21

STEREO FLUXYAlVE, STE REOPlAYER, COLLECTOR S SERI ES" PRO· STANDARD SERIES, CALIBRATION STA. N DA RD AR E lRAO EMI\RK$ USED TOOENOl e QUALITY OF PICK ERING COM PANY, I NC. PRODUCTS. A Case for the Custom Console

F. H. JAC KSO 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 One problem faced, and no doubt COlll­ together with complete component con­ description of the genus homo sapi­ mon to fellow devotees of the audio art, sole housing for all program and ampli­ Tens' lifetime as the "Seven Stages of is the ever present problem of combining fication somces. (See Fig. 1.) The cynic NIan," one might as easily draw the audio component quality with living so easily states that given appropriate simile anent the genus "audiofan" ! For­ room decor. Optimizing the equipment sums most problems are solved. To con­ tunately for the writer, and his acquain­ quality somehow always seems to out­ found this crass viewpoint, the writer tances, fired with the desire for fine re­ strip the desires of the distaff side to offers this system and in particular his production of music in the home, the decoratively house that which husband solution to the task of creating a fur­ stages are confined to three in number, hath wrought! nitme setting for such a system at a whose total duration need not necessa?'iZy Secondly, there is need for convenient total cabinet cost of under $100! This sum to a lifetime ! access, coupled with easy component re­ ca binetl'Y cost was not predicated upon The first might prosaically be termed lllovability. Thirdly, it was desired to ownership of an extensive inventory of the planning stage, wherein the audio incorporate in the design the quality of power tools. On the contrary, the au­ literatm'e is combed not less avidly than adaptability, i.e., obsolescence conver­ thor's sole claim to a power workshop are the shelves of the neighborhood em­ sion. Lastly, convenience featm'es com­ is a vintage electric drill with a $12 porium devoted to such wares (presided patible with the design criteria were to sabre saw attachment! over by the ever-patient proprietor). be incorporated. How well the solutions The second might be termed the stage to these problems wear is the continuing How W ere These Items Constructed? of creation. Decision, ever procrasti­ subject of both this article and the third nated, has finally molded actions. Within stage of this audiofan's career in high At the risk of offending the power short days passing om scrimped savings fidelity. tool sellers, we must state that most local fast disappear into the maw of desire! The basic system chosen (see appen­ lumber yards, for a very nominal charge, The third stage, for lack of 111<1re apt dix) was to be that of a three unit stereo will cut and mill any raw stock to yom semantics, might be called the contem­ presentation of both high-fidelity broad­ working drawings. On my unit the toler­ plative. This article is being composed cast and phonograph programming. The ances maintained were such that for ease at that most difficult of times. For the three units were to consist of separate of assembly, the method approached the author, the planning and the creation left- and right-channel speaker cabinetry so -called "kit" type of cabinet construc- are over. The satisfaction and enjoy­ ment of a fine concert wafting through his home, is tempered by the gnawing query, "Has the final stage fulfilled the Fig . (be low). promise of the long past first~" The complete sys­ These stages through which the au­ te m. GLUED & thor's system developed are universal NAILED enough in natm'e as to cause the reader Fig . 2 (right). Ex­ BUTT similar concern as he plods his way plode d view of JOINT through that first stage ! the laminated case construction. * 6060 N. Brig7rtview D·r., Glendo1'a, California.

1/4-IN. PL YWOOD FURN ITURE GRA DE

MOLDING

18 AUDIO • FEBRUARY, 1961 f riendly millwright at the local lumber of these moldings on assembly to comply yard was responsible) were coated on with the final tolerances existing on the the underside with glue, as was the several mating items. ' rough case. Carefully fitted, the panels The second major problem to be re­ were butted at all corner miters and solved by our design was that of acces­ weighted until the glue set. The end sibility, It is only within the last several grain in this case was covered by the years that the ogre of maintainence ac­ application of grille molding although cessibility has been given notice, much an alternate method, easily applied, is to less resolution, by the commercial pack­ use plywood tape. This tape method was age interests, and that primarily by the used extensively on the end grain cover­ television receiver manufacturers. It is ing of the console. -Most observers be­ to be seen (Fig. 4) that this problem lieve the cases are of solid hardwood was resolved most easily by the inclu­ Fig. 3. Top edges of the console are cov­ construction, -GSee Fig. 3.) This lami­ sion of a lift-off top in the console de­ ered 'with wood tape. nated case construction and the imple­ sign. This feature greatly eases the dis­ m.entation of the Provincial motif in assembly breakdown of the system into tion. The obvious advantage to this all three cabinets (which helped to create units for repair or transport. In addi­ method is the wide latitude in design per­ a unity of design) through use of ordi­ tion the preamplifier and tuners are so missible, Ve9'sus the justifiably limited nary builders molding,. did much toward inserted into the control panel, that number of styles available from kit beautifying {pe ensemble. The grille their removal is accomplished by simply manufacturers. frames are aefinitely enhanced by the sliding them on their base toward the Another area of expense coupled with' graceful curves of the covering molding. rear of the console for an inch or two. the construction of a console suitable for The console inset doors and the drop This is possible because the normal milady's living room is that connected bezel-type mounting was not employed. with jointing and cementing of large Insteal, a matching rectangle was cut in scale furniture. Rather costly jigs and the panel for each of the three units fixtures are usually required for such to be mounted. As each unit face pro­ construction. Since these items were not trudes about 1,4 inch from the panel readily available to the author, some face, it is difficult to tell whether or not substitution became a necessity. The re­ they ar e permanently affixed. This fea­ sultant innovation, which is felt to be ture has already proved of value in the the prirp.e pne of t):l.Ose in this system, case of some minor repairs to one of the has been termed "laminated case con­ panel units, The operation took less than structioiI". (See Fig. 2.) Cabinet makers a half hour, including repair of the unit. may shudder within their professional The third criterion for our design, in stoicism to learn that this metlio.d uses which it was desired to create solutions common finishing nails and. qllick-set­ amenable to our other goals, is that ting casein cement! The method ~as first called adaptability, or obsolescence tried on, the construction of the .s·peaker conversion. One area in which this at­ cabinets and the encouraging r esults tribute was incorporated was the design 'V t prompted the use· 'o:f? the' same method, of the speaker enclosures. Close perusal without modificatiJm, in h)!>ilding the of Fig. 5 will reveal the method used to console, ' ".'\ allow for f uture horizontal placement The procedure consists of two steps. of the speakers, should the need arise. Step one is to simply butt the sides and The bases' are entirely separate from the nail using casein glue (,several national Fig. 4. The top is off! Note the laminated speaker enclosures, and the enclosures case construction in the end panels. brands are available) . . Three-quarter­ are finished on all four sides. They need inch fir plywood i;; adequate. After front have that added touch of detail, only be lifted off their bases, placed on counter-sinking the nail heads, the case which would be noticealy lacking were the side (after orienting the horn is rough sanded to remove any gross ir- these panels of plain surface. Mention tweeter) for f unctional use as a book­ regularities on the surface. Previously should be made at this juncture, that a shelf enclosure. cut and corner-mitered, 14 -inch, furni- contribution to the over-all effect was In line with solution to the problem ture-grade, plywood panels (again the gained by the hand fitting and mitering (Contimted on page 79 ) Appendix System Parameters

Component Function Mfr. Model AM-FM Tuner Right Channel Either Pilot FA-670 AM- FM or FM-FM stereo (see below) FM Tuner Left Channel FM-FM Heath FM-3 Stereo Turntable Record Reproduction Fairchild 412 Tone Arm Record Reproduction ESL S-1000 Cartridge Record Reproduction Shure M3D Preamp Control Center Dynakit PAS-2 Amplifiers (2) Left and Right Channel Allied 83 YU 793 Power Output Speakers (2) University CUL 10 (kit form of 2 way SLOH system) Cabinets (spkr) Custom To Univ. CUL 10 Fig. 5. The bases are separa te and the Specifications enclosure finished on a ll sides to permit Custom Console a variety of placements:

AUDIO • FEBRUARY, 1961 19 "Ersatz Stereo" Unlimited

C. H. MALMSTEDT*

A multichannel monophonic system that gives stereo some impressive competition.

NA RUSTIC HOME in California there proven, an Altec 515 woofer also was is a monophonic hi-fi installation salvaged from the earlier installation I that, in results achieved, matches the (where it had been in an infinite-baffle grandeur of the country around it. arrangement stabilized by a half a ton "As good as stereo!" the system has of concrete within a wall) for modifica­ been acclaimed. And, by a visiting sym­ tion and use in the present system, as phony conductor. was an Altec 604-B coaxial speaker sys­ "Magnificent ! It is as though I were tem, along with associated crossover standing on the podium, the orchestra networks. right here before me !" With these and other units as a start­ Whether or not these accolades are ing point, the present unique installation extravagant, the fact remains that got under way in 1951, many years be­ "monophonic" applied to this installa­ Fig. 2 . The music corner, with part of the fore the advent of commercially avail­ large lib ra ry above and below the turn· tion is as pleasantly deceptive as the tables. Note the home·built turntable on able stereo. As with all lovers of fine name "Erosion Acres" is for the home the left. music, the goal of the Dyers was not and grounds that house this audio system only high fidelity but as well concert hall created by its owner, Mr. Harwell Dyer in and about the large living room, but realism. It soon became apparent that of Carmel Valley. so placed that, while everything is "How," all ask, "do you get such readily accessible, little is in evidence to marvelous sound from an installation mar the furniture grouping, the decor that looks so simple?" of the room, and the magnificient view The answer is: growth, of more than from it. twenty years' duration; growth born of Interestingly, the original heart of the a constant desire for improvement-of amplifying system still serves as one of the technical facilities and of an under­ the power amplifiers- proving that the standing of music, a knowledge of the best is always in the long run the cheap­ composition of the sounds t.hat were to est, and that modification intelligently be reproduced with the best possible applied can obviate the too-often-as­ ftdelity; things, in fact, that are not sumed necessity for discarding good come by cheaply, in either time or units merely because of age. Designed money. and built in 1946 by Dyer and William Considered by the standards of to­ Hilchey, this 300-watt amplifier utilizing day's hi-fi, Mr. Dyer's begiuning was, 6L6 tubes feeding two 845's, in push­ however, a modest one. A Gilfillan radio­ pull, employed the best components then phonograph with a Garrard changer available. Originally part of a 300-pound handling only 78-rpm discs was, back in rack-mounted composite unit, this am­ 1938, the first nucleus of the system. plifier was later converted by James Today, the Carmel Valley installation Meagher into a Williamson class-A am­ consists of six speakers and twelve elec­ plifier of 150 watts full 'power and 75 tronic units housed in five unit-Iocatiops watts distortionless output. Following the same desire to preserve and effec­ * Box 411, Windel'mere, Fla. tively use the worthwhile and the Fig. 3. Electronic cabinet, forme 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 de­ sign and build his own turntable. The Fig . 1. Not stereo result leaves little to be desired, even -but magnificient in these days of many fine commercial music . .. a mag­ turntables. nifi ci e nt view . While few may care to go this far in a pea ce. 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 in­ fluences was the aim. Parts were picked up here and there. I n a wrecking yard was found a 65-pound, 16-inch diameter,

20 AUDIO • FEBRUARY, 1961 the drive-shaft was fastened a six-inch More concerned with fidelity than ef­ length of stiff wire protruding straight ficiency, he decided to use the big home­ out; to the end of this wire a small mag­ made power amplifier to feed an AR-1 W net was attached; at one point on the speaker in its infinite-baffle enclosure, travel-radius of this magnet a micro­ placed on the floor at one end of the switch was so placed as to be actuated room. With the feed originating at the when the magnet passes it the first time. home-made turntable, the Garrard Result: manually start the turntable changer, or a Fisher FM tuner, the slowly- and within one turn or less the AR-1 W woofer receives its input microswitch applies the current auto­ through a Grommes 212 preamplifier matically, and the table smoothly works feeding a Heathkit electronic crossover, up to the speed it was set for-33Ya the Low output of which was set to de­ or 78 rpm. cline at 100 cps. Both the construction time and the With one bass-response channel thus time required to attain full speed (about established, another set of speakers-an a minute) are more than amply justified Altec 604-B coaxial and a 515 woofer­ Fig. 4. Home-made 16-inch turntable. by the performance. "If there is any were mounted on a common infinite two-inches-thick halance wheel once used rumble in evidence, it is inherent in the baffle half the size of a large closet door. in a saw-mill-massive enough and recording, not in the turntable." To accommodate this baffle, the door heavy enough to resist vibration. To one side of this wheel was bolted a 1f2-inch­ thick disc of plywood. Over the plywood -:-::::-::--..... JEN SEN 302A 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 broad­ casting station transcription turntables. Set in an "H" saddle constructed at home, the motor was placed on a foam ALTEC rubber pad within a cabinet under built­ 6048 in bookshelves. To assure vibration-free drive of the turntable, sections of the drive-shaft were separated by Lord rub­ ber couplings, with a free-wheeling de­ vice in one section of the drive-shaft. As a precaution against overheating of ~--...... _ ALTEe 285 the motor during long use, a small rub­ ber-bladed fan of the type used in auto­ mobile interiors was added to the motor compartment. To render its operation --._ ALTEC515 inaudible, its speed was reduced by the use of series-connected light bulbs, which also conveniel'ltly illuminate the enclo­ sure during operational inspections. Fig. 6. Block diagram of the four-channel system. There was one problem: how to start With a GE magnetic cartridge and was I'emoved from a closet at the same this heavy turntable spinning without 16-inch transcription pickup arm on this end of the living room that holds the asking the motor to do it. Solution: to turntable, it became again a case of one AR-1 W. Bottom half of this 6-feet-deep thing leading to another: where a good closet was partitioned off as a housing audio system had inspired the quest for for the rack of major electronic units a better turntable, the turntable thus and power supplies, with the lower half developed now led the way to a demand of the door cut vertically in the center for an even better audio system: "The to provide two flap doors that could, best monophonic thing I've ever heard," without jeopardizing appearance, be left said one listener. ajar for ventilation. The upper half of But it was a desire for a stereophonic the closet thus vacated was lined with kind of realism that brought about the absorbent padding and utilized as an "unorthodox" use of crossover networks enclosure for the two speakers. To the that is one of the keys to the success of same baffle now was added a Jensen this system. This, in turn, was brought 302-A "bullet" tweeter, thus making this about by the physical characteristics of a four-speaker infinite-baffle enclosure the house the Dyers purchased in Car­ about six feet to the left of and about mel Valley. With walls of unsurfaced five feet above the AR-1 W on the floor. concrete block, a floor of smooth, waxed Input to this speaker system was now cement, and a large picture window in arranged through individual channels one wall, plus a rather high beamed to which only the Grommes preamplifier ceiling, the living room was obviously and equalizing system are basically com­ a "live" one. A member of the infinite­ mon. To feed the 604-B coaxial, the Fig. 5. Midrange horn disperses sound baffle school, Mr. Dyer set to work ac­ High output of the electronic crossover, throughout the large room, augmented cordingly-to assure, first of all, ade­ set to pass above 400 cps, was fed into by a woofer at floor level. quate but natural reproduction of bass. (Continued on page 81)

AUDIO • FEBRUARY, 1961 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 prob­ lems. Here is a description of the various computer types plus a specIfic audio design example.

In Two Parts-Part One

N RECENT YEARS, names such as PACE, then make the necessary changes and 650, MANIAC, REAC, 704, and start again. I ESIAC have appeared more and Even the field of audio can benefit more throughout our society. These are through the use of computers. The de­ the 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 meth­ the application of computers, time- and ods. Fig. 3. Shock absorber analog. money-consuming procedures are being By introducing circuit equations into simplified. Each year more people come computers, the laborious task of ampli­ plication in the area of system analysis into contact with these applications. fier design, for example, can be made work where systems must be engineered Utility bills, bank accounts, savings easier. Tube characteristics can be placed and optimized. bonds, credit cards, income tax, govern­ in the computers in order to determine In order to illustrate the differences ment checks, and the paper work of the amplifier tube operating points. A between the two classes, each will be many other everyday activities are han­ more com plex design in terms of com­ discussed in the following sections. dled by some sort of computer. ponent aging effects is readily accom- Since audio design work is of interest In engineering, the speed of data proc­ to the r eader of AUDIO, the major em­ essing is of extreme importance. By free­ phasis will be on the analog computer. ing engineers from routine complex cal­ culations so that they may go into new The Digital Computer endeavors, these machines are stepping The digital computer is a device that up the rate of progress. uses discrete steps to represent numbers Complete models of complex systems while it performs mathematical opera­ can be computer simulated for engineers TIME tions. This is similar to the operation of to study. In this way the cost of optim­ an abacus. On the abacus, beads are used izing a design can be reduced. to represent numbers. Addition and sub­ If a new system were to be built for Fig. 2. Velocity of mass when the pin is traction are performed by the shifting each design change, the cost of develop­ pulled. of these beads. A similar procedure is ment would be many times what it is plished by parameter variation. Changes used in electronic digital computers. In now. Each time a design error was made in resistor, capacitor, and voltage values this case "bits" are used to represent the a new system would be required. Com­ . can be programmed to study the trade­ numbers. A number or quantity is puters, however, allow quick and easy offs between power, bias, and distortion. changes in design. On computers, "mis­ changed to "bit" representation by the Other audio areas such as speaker, takes" are indicated by means of signal use of a code. The "bits" take the form cartridge and tone arm, and tone con­ lights, horns, or other such means. A of either the presence or the absence of trol design can be investigated in similar flip of a switch will return the problem a signal. The presence is denoted by the fashion. to its origina1 state. The engineer can number "I" and the absence by the num­ While most of the computers in use ber "0" when setting up the problem. * 36 Ra'lI Street, Schenectady, N . Y . today are built to perform a specific The over-all number or quantity is then function, they all fall into one or the represented by some combination of l 's other of two classes: analog or digital. and O's, according to the code used. While each class can do the problems By the use of Boolean algebra and handled by the other, there are basic dif­ other techniques beyond the scope of this ferences which make necess'ary a choice article the various mathematical opera­ of which type to use in a particular case. tions are performed. Such a choice is made on the basis of the The accuracy of these mathematical problem and its requirements. Such fac­ operations is limited only by the number tors as problem accuracy requirements, of bits used to represent the quantity. the number of parameters, and their Six decimal places of accuracy imposes changes enter into this choice. no strain on a typical digital computer. The digital computer has its greatest One of the main features of digital use in numerical analysis work where computers is the memory function. By precise bookkeeping-like routines can be the use of this memory a number can be Fig. 1. Shock absorber schematic. set up. The analog computer has its ap- stored in the machine until it is needed

22 AUDIO • FEBRUARY, 1961 to a piston which is immersed in a cylin­ der of oil. The piston has holes in it to allow the oil to flow through. This piston­ cylinder combination is a typical shock Zj IN~UT absorber. What does the velocity of the ':.' ;;; Fig . 4. Operational mass become when the pin is removed' amplifier. From experience it can be surmised that ej the mass will fall with increasing veloc­ ity until the oil is going through the piston holes as fast as it can. At this 0---+_--0 time the mass will have its maximum

A. NO FEE DBAC K B. WITH FEEDBAC K velocity and will keep this velocity until tbe piston strikes the bottom of the cylin­ der. The velocity will take the form for computation. Upon being changed it slide rule. On the slide rule numbers are shown in Fig. 2. can again be stored until further needed. represented as lengths. The operations In order to set up an electrical analog For example, a bank account balance of adding or subtracting of lengths ac­ of this problem it is necessary to write could be kept in a computer's memory. complish various mathematical opera­ an equation of the system. Using con­ When the depositor makes a deposit, the tions. ventional laws of mechanics this equa­ teller, by pushing buttons, could call the In its engineering form the analog tion is: depositor's balance from the memory. computer normally is used in the simula­ l\ix - W + KdX = ~ Forces on mass = 0 The new deposit could be added and the tion of entire systems. While there are (1) new balance put back in the memory mechanical, electromechanical and elec­ where it remains readily available for trical analog computers, this discussion where future transactions. will be confined to the electrical type. M = Mass of the body These memories take three common In setting up an analog simulation the W = Weight of the body = Mg forms: magnetic core, magnetic drum, equations which represent the behavior Kd = Damping coefficient due to the oil and magnetic tape. The rate at which of the actual physical system should be x =Acceleration of the mass information is required in the computa­ available. Electrical circuits are then x = Velocity of the mass tion determines which type of memory made up which obey the same type or g = Gravity acceleration is used. The types are listed in order of class of equations. Voltage and current solving for x and substituting ,lVIg for {lecreasing accessibility. The core is the variables within the electrical circuits W yields: (2) "fastest" memory. The bits take the form ., K'1X of a magnetized or unmagnetized core Zr x=g-M to indicate respectively the "I" or "0." The core memory immediately supplies N ow if an electrical circuit can be de­ the number it contains as often as de­ termined which obeys an equation of the sired. The magnetic drum is a metal same form the analog is found. -drum coated with magnetic oxide. The Using "20-20 hindsight" consider the bit is recorded as the presence or ab­ circuit of Fig. 3. Writing the charge ex­ sence of magnetization in a particular pression for the voltage drops around .area on the drum. The recording is done this loop when Sl is closed we find equa­ Z, by heads similar to tape recording heads. 'n tion 3,

AUDIO • FEBRUARY, 1961 23 feet/second can take various forms of RC networks gain, kIa, where "kl" is the ratio of Ra W Ilel'e [kx 1 = coulomb giving a large variety of functional re­ to Rn + R b, and "a" is the ratio of R f (5b) lationships between the input and the to R i . 2 output voltages. These relationships are The integrator is shown in Fig. 8. In g = k . EOwhere [k 1 = feet/second useful in complex problems. this case the feedback impedance is a g R g coulomb/second The most co=on forms in use are the capacitor. The relation from ei to eo be­ ( 5c) adder and the integrator. If more than comes : K 1 l/second one input impedance is added to the grid M = kt RC where [ktl = l/second 1 point as shown in Fig. 5, the output volt­ eo =_ Zf = __1_=_~ (' ~) =_~ (12) (5d) age will be the sum of all the inputs with ei Zj RjroC RC S S gains determined by the impedance The small k constants are known as ratios as shown in equation 11. In LaPlace notation the ~ signifies scale factors and as seen by their units integration. A simple intuitive approach are used to relate the various quantities eo = - ( Z~ ell + Z~~i2 + . .. . + Zrin) (11) of the actual and the analog system, kt, i1 12 In is given to show that this circuit does is seen to be nondimensional. The nu­ This addition applies regardless of the integrate. From equation 6 the CUl'rents into the grid point equal zero. Then if merical value of these scale factors de­ form of the impedance. If the imped- pend on the expected range of the vari­ el is providing current, ~, a current of ous variables. equal magnitude must be flowing in the It can be seen that the act of closing capacitor. This is possible only if the SI in the electrical circuit is the same voltage across the capacitor is constantly as the act of pulling the pin in the actual changing. For a constant ei the output system. Further, it is evident that the eo is then constantly increasing. This is actual system can be optimized by integration. If ei is removed, eo will re­ changing the electrical quantities until main constant. For simplicity the inte­ the desired operation is achieved. Then grator is given the symbol shown in by using the scale factors the values of Fig. 7. Potentiometer gain adjustment. Fig. 9. the actual system parameters that will The discussion of the integrator im­ cause the same response are established. mediately leads to an analogy. If eo is In analog computer work the basic considered in a particular problem to be building block is the operational ampli­ the position of a body, then el is the fier. Through the use of RC networks in velocity of the body. The relation, again conjunction with the amplifier various using LaPlace notation, is expressed by: mathematical operations can be formed. The symbol most commonly used for ei = - kl Seo (13) the operational amplifier is given in (A) Fig. 8. Integrator operational amplifi e r. For this expression the S signifies dif­ of Fig. 4. In (B) of that figUl'e this am­ ferentiation. By the same reasoning the plifier is shown with an input impedance, acceleration, which can be denoted by Zh a feedback impedance, Zi' and a grid ea is : impedance, Zg. The amplifier gain is G. The input voltage is ei> the grid voltage ea = - k2 Sei = + kl k2 S 2eo (14) eg, and the output voltage is eo. An The minus sign is associated with the expression for the output voltage eo will minus gain of the amplifier. That is, a now be found by using Kirchoff's rule positive voltage at the input causes a that the sum of the CUl'rent into the grid negative voltage at the output. This re­ point is zero. This leads to the expres­ Fig. 9. Integrator symbol. versal of sign is an important point to sion remember in setting up a system simu­ lation. (6) In physical systems one relation ap­ pears more often than any other. This is The relation of the grid voltage to the the so-called "quadratic" response. The output is given by: response of a spring, mass, shock ab­ sorber system as shown in F i g. 10 is of (7) this type. The expression for this system response to an input F (t) is: (8) Fig . 10. Spring, mass, dampe r syste m. Mx+Kdx+Ksx= F(t) (15) By combining equation 6 and equa­ ances are resistors, the unit is an adder. This expression states that the input tion 8 the output over input relation For simplicity the adder is shown in force is balanced by the acceleration, becomes: Fig. 6 where gains a, b, and c are the velocity, and displacement forces of the respective ratio of the input and output mass. Zf ( Zi Zf) eo =_ Zf _ Zj 1 + Zf+ Zg (9) impedances. (In this figUl'e and from If LaPlace notation is used the ex­ ej Zj G now on all voltages are with respect to pression becomes: ground.) M S2x + Kd Sx+Ksx=F(S) (16) It is seen that if G is made very large, Potentiometers can be used to obtain the second term vanishes leaving: gain values. The input voltage, if fed which rearranges to: into a potentiometer, will appear at the eo Zt x I/K. arm with a gain between 0 and 1 de­ = (17) el =- Zi (10) F(S) M S- Kd S 1 pending On the potentiometer setting. --+- + This is the basic expression for use in Thus, in Fig. 7 the input voltage appears K s Ks analog computer work. The impedances at the amplifier output with the overall (Continued on page 83)

24 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 standard for directional microphones and no directional microphone 664 cardioid dynamic "sees" and transmits a faithful replica of reality­ without Variable-D can match its performance characteristics. These neither adding nor subtracting, without coloration or distortion. Through characteristics allow its use at greater working distances and provide its smooth response, wide range, and rejection of unwanted sound, needed feed-back protection. Response is smooth and peak-free over a public address technicians, radio amateurs, and tape recorder owners broad 40 to 15,000 cps range. Placement and handling is non-critical. can now obtain the accurate, natural sound pick-up that was once the A single moving element-the indestructible E-V Acoustalloy® dia­ exclusi"e property of the broadcast engineer. phragm-withstands high humidity, temperature extremes, corrosive Utilizing the exclusive Electro-Voice Variable-D® principle, the "664" effects of salt air, and severe mechanical shocks. The 664 is sturdily features highly directional sound selectivity; reduces pick-up of reverber­ constructed, inside and out, assuring a long, trouble-free life of de­ ation and ambient noise up to 50%. This E-V patent set an entirely new pendable 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 Commercial Products Division 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.) 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 recorde r with respect to noise.

OISE IS A FUNDAM.ENTAL limitation in cording necessitates maximum gain at vidual hum components. The noise in the all recording processes. Unless a low frequencies. It was felt that a some­ two lowest octave bands is contributed Nlow noise level is achieved, true what detailed examination of the noise almost entirely by the hum components, high-fidelity sound reproduction is im­ from a tape recorder would be of inter­ 60 and 120 cps, and is essentially un­ possible because low passages will be est. A Movicorder tape recorder was em­ changed when the tape is stopped. heard against a background of interfer­ ployed operating at a speed of 7.5 inches Above 200 cps, however, the noise comes ing and unwanted sounds. Low noise per second. principally from the tape, and residual level with consequent wide dynamic electrical noise (Curve C) is negligible range is a characteristic of modern mag­ Tape Noise Frequency Analysis in comparison to it. The amplifier has netic tape recording First. a portion of tape containing a the capability of playing much quieter tapes in the future as they are developed. Signal-te-Noise Ratio 250-cps tone recorded at maximum level was reproduced to give a reference out­ Small difference between noise for bulk­ Signal-to-noise ratio in magnetic tape put reading. Then, erased tape was re­ erased and machine-erased tape indicates recorders is ordinarily expressed as the produced without alteration of the play­ good balance in the erase oscillator. ratio of rms single-frequency signal at back amplifier gain while noise output the level yielding 3 per cent harmonic was measured through the electrical fil­ C~mparison With Room Noise distortion, to total noise measured over ters of two types of frequency analyzer. the complete reproducing frequency Figwre 1 shows the results of the noise It is important to the success of mag­ range. The 3 per cent point represents measurements made with a narrow band netic recording that the signal-to-noise the maximum permissible recording level (25 cps) and an octave band analyzer. ratio at higher frequencies is much greater than the usual single number for signal peak amplitudes, and is usu­ The usual signal-to-noise ratio described ally measured at 250 cps. above is shown by the line at "Over-all" discussed above. The octave-band levels When the signal-to-noise ratio is ex­ to be 52 db. With the octave filters, noisc are roughly constant and are about 75 db below the standard 3 per cent distor­ pressed as a single number in this man­ was checked for three conditions: tape ner for magnetic tape recorders, it essen­ erased in the machine (Curve A), bulk­ tion level. Figure 2 has been prepared to tially represents a signal-to-hum ratio. erased tape (Curve B) and tape stopped explam the significance of this. Rather Hum reduction is particularly difficult showing only playback amplifier noise than ratios, this figure shows actual with tape recorders because the magnetic (Curve C) . sound levels as measured in a room with reproducing head must be mounted near It can be seen that the over-all level a sound level meter and analyzer. They have been plotted in the special form of motors and power transformers which is mostly accounted for by the noise in produce magnetic fields from which the the two lowest octave bands. Above 300 "masking level"; that is, the level which head must be shielded. In addition, the cps the levels are much lower. At low noise from the reproducing system must playback equalization for magnetIc re- frequencies two sets of "spikes" are attain if it is to be detected in the pres­ ence of the room noise. If it falls below * COn8ultilng Engilneer, Santa Monica, shown, measured with the 25-cps band California. analyzer which could separate the indi- (Oontinued on page 82 )

~~ 1 1I 11m-~~~~~~ffi-~ 60 ,.--,--.,....,.,II,...... ,..I ~11 1 1I.----...... ,...... ,...... ,..,..,n-r---.....---r'TT"'T"T~___, ~ 50 y OVER-ALL oj U II III II ~ 50 1_ (2) 60 cp~s_- -Jj- +_IH-+-I-+Il--I-- I+--++++tlI-tH-----i 1) 01 20 cps

~ 1160 1---+--+--HH-+++lIl~;..:1 ~-H--+--+l (2) OCTAVE BAND LE VEL S H-1I+H---l ~ ' rr1 I '~ ~ ~ I ~ ;~ 70 ~-+--+-41~++~~:-,~~~~~H-~~-A-++---H-b~~~--4 «0 I t; 0 I \ r!_-- ~ ~80~-+--+-~++~~I~~IH--I-~+~+--2~~HH-++*~~~ 0'" I I T'" 3~ I 2 90 ~_+__+_~++~~I~~I~I++T+H+~4~~·~,c~~~~v~~~~~ ~ I I I : z t--t- (1 ) N ARROW BAND LE VELS -HHtI--I-- I+----+-H++II-+H- --/ Uli 1II IIIi lill 1'1 'II I l 00,:·~~·~' ~· ~~IOO~~~~~~' -·~~I ~_--~~~~L, ~· A+,~OOOOL-~'OOOO 100 1000 10000 '0000 FREaUENCY IN CYCLES PER SECOND FREOUENCY IN CYCLES PER SECOND

Fig. 1. (l eft) Results of noise measureme nts on a typical re corder. Fig . 2. (right) Re corder noise compare d to room background noise for typical quiet room. Above 200 cps shown as octave bands; be low 200 cps shown as single tones.

26 AUDIO • FEBRUAR Y, 1961 WITH GOODMANS LOUDSPEAKERS

... IT'S WHAT YOU

DON'T..•...... SEE THAT COUNTS!

AXIOM 80: 10" custom-built twin-cone transducer capable of maximum sound repro­ TRIAXIOM 212: Finest value ever offered in an integrated 12" three-way loudspeaker. duction accuracy at medium power levels. The moving assembly is "free-edged," sus­ Extra-heavy, high-efficient magnets for maximum performance. Smooth, undistorted pended on two sets of double·acting cantilevers providing extremely low and linear response from 20 to 20,000 cycles. Unusually sturdy construction with rigid, die-cast axial stiffness combined with strong radial centering .action: Cast chassis. Frequency chassis. Power handling capacity, 25 wafts, total flux 178,000 Maxwells. The test range: 20 to 20,000 cycles. Power handling capacity, 15 watts. Flux density: 17,000 graph below charts the smoothness of the GOODMANS TRIAXIOM 212 (solid line) as gauss. Most efficient 10" and widest range free-edge cone speaker...... $68.50 compared to two leading competitors ...... $69.50

I 1~j.:===· : 1 f HI AXlo1!fftII"-,,----====='1. I Imf~tF~- '"AXIOM''' ~ .1 CO~, ~;TANT TEST CONDlll?NS: Microphone 18" on axis. Anechoic conditions. Infinite baffle. Input, 1h watts at 400 cycles

Need proof of the clear, clean, true sound reproduction of a perfect example of British precision and craftsmanship. loudspeaker by GOODMANS? First, check the response curves One of the many outstanding custom features on all GOOD­ charted above. They dramatically reveal the smooth, un­ MANS speakers is the "Rigid-Flex" cone ... a completeiy flex­ distorted frequency respORse over the audio spectrum. Trans­ ible, free-floating cone rim and completely rigid cone center lated into musical terms, the GOODMANS speaker reproduces to provide pure piston action. sound with proper balance, clarity and realism ... achieving The final test, and proof, of GOODMANS superiority •.. will be perfect separation of instruments, peak-free highs and well­ your own ear. You'll see why, when it concerns high-fidelity, defined, clear bass tones. This quality instrument is the your loudspeaker has the final say!

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Incorrect bias can increase distortion, reduce the amount of signal recorded, and also decrease high fre­ quency response. Here is an explanation of biasing which will answer many questions as to how and why.

HERMAN BURSTEIN AND HENRY C. POLLAK':'

NLY IN ONE RESPECT-the oscillator such as tape duplicators, where erase is trast, erase heads require a good deal -do tape amplifier circuits differ not required, current is supplied only to more current in order to perform ef­ Oradically from the circuits nor­ the record head. fectively. A typical erase head may mally found in control and power amp­ Bias current in the record head serves require from 15 rna upwards. lifiers. Otherwise, the tape amplifier two vital purposes. It increases the employs similar means for the similar amount of signal recorded on the tape. Oscillator Operation tasks of amplifying signals, controlling It reduces distortion. Unfortunately, as Most oscillators employed in tape re­ gain, shaping frequency r esponse (equal­ bias current is increased above a cer­ corders operate by applying positive ization), minimizing noise and hum, and tain point, high frequency response feedback between appropriate tube ele­ performing various switching functions. deteriorates. H ence one must guard not ments, usually between plate and grid, Accordingly, the technician or audio­ only against insufficient bias current, in an amount sufficient to sustain oscil­ fan conversant with audio amplifier which results in excessive distortion and lations in a tuned circuit consisting of a circuits should not find tape electronics poor signal-to-noise ratio, but also coil and capacitor. The values of the presenting essentially different problems, against too much bias current, which coil and capacitor essentially determine except for the oscillator. Therefore it is produces severe treble losses. The slower the frequency of oscillation. the purpose of this article to provide a the tape speed, the greater are these The operation of a tuned-circuit oscil­ basic understanding of the oscillator high-frequency losses. lator is a complex process, with many Bias current requirements of record circuits commonly found in tape re­ things happening at once. A complete heads are usually quite modest, on the corders. Such an understanding will fa­ description requires tracing over one cilitate the work of the individual seek­ order of 1 ma for many heads. In con- cycle of oscillation the phase relation­ ing to restore a tape oscillator to correct ships between voltage and current in operation, to improve its performance, electromagnetic and electrostatic fields or to build a tape amplifier capable of and in a -tube circuit. Instead of going recording satisfactorily. through such an analysis, this article will attempt to provide a simpler, basic Functions of the Oscillator insight into how an oscillator works. The oscillator operates only when the A fundamental explanation can be tape recorder is in the record mode and based around Fig. 1) a simple oscillator supplies high-frequency current, also similar to that actually found in many known as bias current, to the record moderate-price tape recorders. To under­ and erase heads. The frequency is usually stand why oscillation takes place, it is between 40,000 and 100,000 cps. In a helpful to consider fu·st just the tuned few recorders employing a permanent circuit, comprising C1 and L1. Assume magnet for erase or in special machines that for some reason the upper plate of C1 is charged, that is, contains more * Authors of "Elements of Tape Re­ Fig. 1. Single-ended oscillator employing corder Circuits," Gernsback Library. plate-to-grid feedback. (Continued on page 32)

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TAPE RECORDER-PLAYER .:...... _...... cluding those due to coil resistance, ca­ GRID- LEAK RESISTOR, pacitor leakage, and the load presented TAPE GUIDE by the tape recorder heads and other GRID- LEAK ([1'om page 28) circuit elements. For oscillation to be BIAS AND sustained, the tuned circuit needs out­ ERASE _ ·n ...... -+--I electrons than the lower plate. Seeking CURREi--n side aid. This is similar to the child on a equilibrium, electrons tend to flow from swing, who keeps moving as the result the upper to the lower plate through the of a moderate systematic push from path afforded by L1. This flow creates someone on the ground. an electromagnetic field about the coil The tuned circuit receives systematic and, by Lenz's Law, induces a voltage aid from the tube circuit with which it is across the coil of a polarity such as to Fi g . 2. Sing le-ended oscillator e mp loying associated. When the upper plate of Gl prevent electrons from flowing rapidly cathode-to-grid feedback. is to be charged, matters are arranged so through the coil. Thus the electron flow that tube current increases, thereby send­ away and for the electrostatic field of gmdually reaches a maximum and then ing more electrons to this plate. Con­ Gl to do the same. The larger the in­ starts to slow down as the charges on versely, when the lower plate of Gl is the upper and lower plates approach ductance of Ll, the longer its field takes being charged, tube current decreases, to grow and fall. Similarly, the larger equilibrium. However, when the rate of sending more electrons to this plate discharge of electrons from the upper to the capacitance, the longer it takes to (from the viewpoint of a.c., a decrease discharge electrons from one plate to the the lower plate begins to slow down, the in tube current is in effect a flow of other. At the oscillation frequency, the field of Ll begins to collapse. By Lenz's electrons from B-plus toward the tube). Law, a voltage is again induced which charge 01' discharge rates of the two The purpose of L2 in Fig. 1 is to vary opposes the change in electron flow components are equal, and they work in the grid voltage in a manner which through the coil. Thus the collapsing unison: the electromagnetic field stores causes tube current to assist the oscil­ energy for the same pel'iod that the ca­ electromagnetic field promotes the con­ lation process. The changing electro­ pacitor is able to deliver it, and in turn tinued flow of electrons from the upper magnetic field of Ll cuts across L2 and, the capacitor stores enel'gy for the to the lower plate. In this manner the by transformer action, induces a voltage same period that the coil is able to de­ lower plate collects not just enough across L2- that is, between grid and liver it. electrons to restore equilibrium with re­ ground. The windings of L2 are so con­ Another way to appreciate why a spect to the upper plate (zero voltage nected to grid and ground that when circuit such as Fig. 1 oscillates at one across the capacitor) ; rathel', it accum­ tube current is increasing the grid end particular frequency is to consider the ulates an excess of electrons compared of L2 goes positive, which causes a impedance between the plate side of the with the upper plate. further increase in tube current. This of tuned circuit and ground. (It should be Eventually the coil's field has fully course is positive feedback. Similarly, recognized that the bottom of the tuned collapsed so that no more electrons ar­ when tube current is decreasing, the rive at the lower plate. Now this plate circuit is effectively at ground so far as grid goes negative, resulting in a further a.c. is concerned because of the filter has an excess of electrons; in other reduction in tube current. capacitor associated with B-plus.) Max­ words, the capacitor has an electrostatic The cumulative increase or decrease imum impedance of the tuned circuit field, which is the counterpart of· the in tube current which takes place due to occurs at the frequency where the react­ coil's electromagnetic field. Therefore, positive feedback approaches an end ances of Ll and G1 are equal. For any electrons begin to flow from the lower to when the charge on either plate of Gl other frequency, the impedance is less, the upper plate through the coil. As approaches maximum. There is a slowing S0 that either the coil 01' capacitor tends before, an electromagnetic field is built collapse of the magnetic field around Ll to serve as a shunt to ground. Conse­ up around Ll and, when this field col­ and eventual reversal of this field as Gl quently, alternating current developed lapses, it results in the continued ac­ approaches maximum charge and then through oscillation tends to be shunted cumulation of electrons on the upper begins to discharge. This results, through to ground except at the frequency where plate of Gl, so that the original state of transformer action, in a decrease in grid impedance is maximum. matters is restored: an excess of elec­ voltage (positive or negative as the case Once started, oscillation in a tuned trons exists on the upper plate. This may be) and eventual reversal of grid circuit would theoretically continue for­ completes one cycle of oscillation. polarity. ever were it not for various losses, in- Assuming no resistance in the coil and Though belated, an explanation of no load, the tuned circuit produces a how oscillation gets started is now ap­ AUDIO perfect sine wave, eminently desirable OUTPUT ...... propriate. Assuming that B-plus has for tape recording purposes to achieve a TRANS FORMER' been applied to the circuit and current minimum of noise. In practice, this is, supplied to the tube heater, initially of course, impossible; some distortion is there is zero voltage between grid and always present. However, oscillator cathode. Due to the random motion 'of waveform distortion and resulting noise electrons emitted from the cathode, a are kept to negligible quantities in high­ minute voltage will appear at the grid. quality tape recorders. Assume that at a given instant this volt­ The frequency of oscillation-or the age is positive-going. Therefore the cur­ time requiTed for one cycle-essentially rent through the tube increases. This depends upon the values of Ll and Gl; increase in tube current results in a to some extent it is also governed by B+ _-----' charge on Gl, a change in the electro­ the slight amounts of inductance and magnetic field of Ll, positive feedback capacitance found in the tube and other BIASANERASE~ at the grid, a further increase in tube components associated with the tuned CURR ENT current- and the process of oscillation is circuit. The coil and capacitor values, in on, as already described. conjunct'ion with each other, determine Grid-Leak Bias how long it takes for the electromag­ Fig. 3. Use of the a udio output tube as netic field of Ll to build up and die an oscillctor in the record mode. The purpose of grid resistor Rand

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AUDIO • FEBRUARY, 1961 33 grid capacitor C~ in Fig. 1 is to provide coupling between LI and L~) thus limit­ respect to the lower plate. It should be the oscillator tube with the requil'ed ing the voltage fed back to the gTid. kept in mind that the process of positive negative gTid bias. The amount of grid feedback and the turning points from bias depends upon the magnitude of Oscillator Variations increasing to decreasing tube current are under control of the tuned circuit, oscillation needed-within the tube's There are several variations of the which determines the rate of increase and capabilities. When the grid goes posi­ single-ended oscillator of Fig. 1. In a decrease in tube current and thus the tive and draws current, the resulting popular variation, the oscillator coil is frequency of oscillation. electron flow charges the top of the ca­ in the grid-cathode circuit, as in Fig. 2. Finally, it may be pointed out that pacitor. The only path for the capacitor For positive feedback to occur here, it is while the locations of the grid-leak re­ to discharge through is the grid resistor. necessary that the grid go positive rela­ sistor and capacitor are different in Fig. As electrons leak slowly from top to tive to the cathode when tube current in­ 2 than in Fig. 1, the action is exactly bottom of the capacitor through the re­ creases, and negative when current de­ sistor, this flow causes a negative d.c. creases. Positive gTid-cathode voltage, the same. voltage to appear at the top of the re­ in turn increases tube current, and nega­ sistor. This voltage al:3o appears at the tive grid-cathode voltage decreases it. Double-Purpose Oscillator control grid. The cumulative buildup or decrease in The majority of moderate-priced tape The negative grid-leak bias reduces tube current is controlled by the tuned recorders contain a small speaker and a the transconductance (gm) of the tube, circuit so as to sustain oscillation. power amplifier, usually single-ended, and thereby the gain around the com­ Assume that the current flowing from for playback purposes. As a measure of plete oscillation loop. If the loop gain is ground through the lower part of oscil­ economy, a number of these machines greater than 1, as it must be for oscilla­ lator coil L and then through the tube is convert the audio output tube to an tion to start, the amplitude of each suc­ momentarily increasing. This increasing oscillator in the record mode. In a few cessive oscillation will be greater than current induces a voltage across the instances, a similar double function is the previous one. This causes the grid to grid-ground portion of the coil such as served by other tubes. For example, in swing more into the grid current region to oppose the increase. That is, the in­ one recorder the playback input stage on each positive half cycle, resulting in ductive reactance of the coil causes a becomes an oscillator when recording. more grid-leak bias. But the bias affects voltage drop across it, causing the Figu1'e 3 shows a circuit in which the the transconductance markedly; the audio output tube doubles as an oscil­ greater the negative bias, the lower the lator. LI and L2 constitute the oscillator gm' So each positive grid swing results coil, providing plate-to-grid feedback. in added negative bias, reducing the gm, The primary of the audio output trans­ and hence the gain, until the loop gain is former is in series with L • Capacitor exactly 1. The amplitude of the oscilla­ 1 C ~ across the output transformer pri­ tions will remain at this value very mary offers a low-reactance path at the closely. oscillator frequency between the plate of The self-regulation of the grid-leak the tube and the primary of the oscil­ bias system is not perfect, but is suffi­ lator coil. Similarly, LI of the oscillator cient to make the oscillator relatively coil offers a low-reactance path at audio insensitive to line voltage variations, frequencies between B-plus and L ) the changes due to normal heating of the s output transformer primary. components, and tube aging. Fig . 4. Typical push-pull oscillator. 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 Push-Pull Oscillators oscillations are getting smaller, each action, the positive-going voltage at the The great majority of professional positive grid swing recharges the ca­ cathode appears as a still more positive and semi-professional tape recorders and pacitor, thus maintaining the bias volt­ voltage at the grid, causing a further a fair number of moderate-price ones age. The time constant of the grid-leak increase in tube current. Thus, as in Fig. employ a push-pull oscillator, custom­ capacitor and grid resistor. (product of 1, positive feedback is present. The volt­ arily using the two halves of a dual R times C~) determines how long the age between grid and ground causes ca­ triode such as a 12AU7 or 12BH7. While capacitor can discharge through the re­ pacitor C to charge, making the grid-end one triode is in the positive half of its sistor before the voltage has dropped , positive and the ground-end negative. oscillation cycle, the other is in the neg­ appreciably. This time constant should Since the tube CUl'l'ent cannot increase ative half. Thus, symmetrical forces are be about 5 to 10 times the period of one without limit, the tube current eventually at work, reducing even-harmonic dis­ cycle of oscillation to maintain grid bias reaches a maximum, that is, a steady tortion. Distortion in the bias waveform adequately. For example, if the oscil­ value. As a result, there is no longer an is a source of noise. The greater the de­ lato): frequency is 50,000 cycles per sec­ induced voltage due to tube current mands upon the oscillator to provide ond, one cycle is 1/50,000 second, or 20 increasing. Consequently the grid-to­ enough current for adequate erasure, the microseconds (Ilsec); 10 times this ground voltage decreases and capacitor greater is the likelihood of distortion. amount is 200 -Ilsec. The time constant of C discharges upward through the coil. Because of its lower distortion for the the 100,000 ohm resistor and .002 micro­ As the grid-to-ground voltage de­ same output, the push-pull oscillator is farad capacitor in Fig. 1 is 200 Ilsec. creases, the grid-to-cathode voltage de­ favored. Although grid-leak bias keeps the creases and so does the tube current. Figure 4 shows a typical push-pull os­ amplitude of oscillations from being ex­ This induces a voltage in the lower por­ cillator. Feedback is from the plate of tremely great, it is very desirable also tion of the coil, this time negative at the VI to the grid of V~ through capacitor that feedback be limited so that the tube top and positive at the ground end. As C~j and from the plate of V~ to the grid operates within the linear portion of its before, autotransformer action causes of VI through capacitor C s) C1) as well characteristic in order to maintain an the grid to go more negative with respect as C~ and CS) together with coil L essen­ oscillation waveform with minimum har­ to the cathode, further reducing tube tially determine the resonant frequency. monic distortion. In the case of Fig. 1, current, making the grid still more neg­ Assume the grid of V I is positive­ feedback is controlled by using a proper ative, and thus assisting the upper plate going at a given instant. This produces a ratio of turns and the right amount of of the capacitor to go negative with (Continued on page 82)

34 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-37 A 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. .

fl." ((,pC/elll/t"St,'"',, SONY ~ SUPERSCOPE INC., SUN VALLEY, CALIFORNIA

AUDIO • FEBRUARY, '1961 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 contor­ tions" may help in selecting the loudspeaker best suited to your requirements.

NORMAN H. CROWHURST*

HIS IS NOT an article on how to de­ The more conventional dynamic type column gives the equivalent electrical sign a loudspeaker. For one thing, loudspeaker Ui;;es a voice coil, the cur­ quantity in the analogy, while the right Tvery few readers are likely to have rents in which ,produce mechanical force, hand column gives the acoustical quan­ the opportunity of designing their own which in turn drives the diaphragm, and tity that corresponds. In this system of analogy we make loudspeaker. On the other hand, anyone the diaphragm, by contact with the air, pursuing audio as a hobby is interested force equivalent to voltage, but this does produces movement in the form of in good reproduction and hence is con­ not say we can convert force into volt­ sound waves. So we have two transfers cerned in getting a good loudspeaker. age in an electro-mechanical transducer. In this connection, many are wanting to of energy to think about, electro-me­ If we use an electrostatic device, it is know "what the score is" about the dif­ chanical from the voice coil to the dia­ true that the electrical voltage produces ferent ways of designing a loudspeaker phragm, and mechanical-acoustical from a deflection force on the diaphragm, but system. This is because the fact still re­ the diaphragm to the atmosphere. when we use a dynamic device, such as mains that the loudspeaker is the weak­ est link in the reproducing chain and because of the divergence of design ap­ proaches used in the products available in this field. To clarify this matter we will explain some of the simple principles of loud­ speaker design, so that those interested can better understand how different ap­ WAVES IN proaclles to the problem attempt to ROPE achieve their objective. The aim of' any t system, of course, is to convert the elec­ trical 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 Fig. 1. Showing the manner in which transverse waves are set up in the cone or at the output of the amplifier, regardless diaphragm of a loudspeaker: (a) a section through the voice coil and diaphragm; of the frequency and amplitude of the (b) an analogous form of wave propagation. fluctuations. Unfortunately, however, to date there is no direct means that is The Use of Analogies a moving coil loudspeaker, a different commercially practical, of transferring A great help in understanding what transfer takes place; it is current that electrical energy into acoustical (lnergy happens is the use of analogies. When is responsible for producing driving Without going through some mechanical we start to learn about electricity, we force in the coil former; movement of medium. The nearest practical approach often use analogies, from mechanical or the coil former in turn produces voltage. to this is an electrostatic loudspeaker. other spheres, to help to explain the So if we were to use the direct trans­ But this has to · have a diaphragm to behavior of electricity. Now that elec- ference that occurs in a moving coil transform the electrical force between transducer, we should reverse the order honic circuits have progressed so far, of the analogy and make current corre- its plates into mechanical movement of and the general understanding of them spond with force and voltage with move­ the air. improved so well, it is often helpful to ment. On the other hand, in the electro­ * 216-18 40th Ave., Bayside, N. Y. reverse the procedure and use electrical static transducer, it is the voltage that Table 1 circuits as analogies for mechanical or produces force on the diaphragm; while acoustical behavior. movement of the diaphragm causes Mechanical Electrical Acoustical system system system An important thing to realize is that charge to flow in or out of the transducer an analogy is only a convenient parallel in the form of current. To avoid confus­ Force Voltage Pressure way of thinking. It does not express ing the issue, we will only use the one Velocity Current Volume move- analogy. . . ment identity, nor does it relate quantities Following the analogies down, they Displacement Charge Volume dis- that can be transformed dl'rectly from placement are fairly simple to follow; mechanical Friction - Resistance Viscous action one to another. friction corresponds with resistance. Mass I nductance Air mass Table 1 lists the more conventional This is evident because both are respon­ Compliance Capacitance Air compliance analogies used. The left hand column sible for the dissipation of energy in Lever Transformer Change in area gives the mechanical quantity, the center their respective systems.

36 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 over­ loud, over-resonant, over-brilliant sound, but to the faithful re­ creation of a musical performance.

The ultimate test of a high fidelity system, then, is a direct com­ parison with the sound of the original instru­ The moment of transition from live to recorded sound: AR-3 speakers and Dynakit amplifiers ments. 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 play­ ing 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 demon­ strate 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., 24 Thorndike Street, Cambridge 41, Massachusetts DYNACO, INC., 3912 Powelton Avenue, Philadelphia 4, Pennsylvania AUDIO • FEBRUARY, 1961 37 Mass corresponds with inductance : the behavior of a loudspeaker. We have applied at the inner periphery of a the mass or weight of a moving object, a driving force from the voice coil, the loudspeaker diaphragm, to the outer which is called its inertia, tends to con­ object of which is to produce a move­ periphery is in terms of a mechanical tinue its course of movement until a ment of the diaphragm for the purpose transmission line. The force applied is force is applied to change it. Force is of transmitting the energy to the air on approximately transverse. This is illus­ needed to start the movement, and again a uniform voltage-pressure basis. To trated in Fig. 1. In our ideal conception to stop it. In electrical circuits, using figure out an equivalent electrical circuit the diaphragm should move back and the analogy, this is the characteristic of for the mechanical action, we have to forth as an entity with the voice coil, inductance where the current tends to be think about what opposes the movement but due to its mechanical compliance or steady and has to have a voltage applied due to the force supplied by the voice stiffness and its effective distributed in order to change it. coil. mass, in conjunction with the effect of A compliance corresponds with a ca­ This is equivalent to the impedance air in contact with its surfaces, it tends pacitance : application of a force pro­ presented to an electrical source voltage. to behave like a length of string or rope duces a deflection or displacement in the The current accepted by the impedance when one end of it is waved to and f ro compliance that will remain until the is analogous to movement: the lower the sideways. The essential difference from force is removed, the same as applica­ impedance, the greater the current; the this analogy is that the length of string tion of a voltage produces a charge on lower the mechanical impedance, the is 1'elatively flexible, while the dia­ the capacitance. When the pressure on greater the movement produced by a phragm is 1· elatively rigid. However, a compliance is changed, the mechanical given force. So if forces due to two the same kind of effect occurs to a device moves. When a voltage on the kinds of mechanical reaction are both limited extent. capacitance is changed, current flows in combining to oppose movement of the The transmission velocity or speed at or out of it. voice coil, these two forces must be con­ which the wave travels outward from In an electrical circuit a transformer sidered as equivalent to components of the voice coil is similar to- or not ve1'y changes a combination of high voltage impedance in series. The movement, cor­ different from-the speed of sound in with low current to a lower voltage with responding to current, is common to air which, in very round figures, is 1000 higher cUlTent, or vice versa. It changes both and the force that they produce, feet per second. Using this figure, a the relationship between voltage and due to their reaction, will be dependent wavelength at 1000 cps occupies one current at which energy is transmitted. upon the movement. foot, which gives us a useful basis for In mechanics a lever enables a small Assume for the moment that the voice considering when this transmission ef ­ force with a large movement to produce coil with the diaphragm forms a rigid fect could set up interference patterns. a large force with a small movement or assembly and the only forces that will At high frequencies, where the wave­ vice versa, thus performing a function oppose its movement are due to the air length is shorter, the distance from the in mechanical circuitry similar to a in contact with the two sides of it. These voice coil to the periphery of the dia­ transformer in electrical circuitry. two columns of air reflect as two im- phragm becomes several wavelengths of transversely propagated wave, so the +10 . Fig. 2. The effect diaphragm can break up into patterns of the transve rse due to the reflected wave (if any reflec­

..0 waves in the dia­ tion occurs). This is the cause of the ir­ l' .,.., If! phragm on t h e ... 0 f. .A regularity in frequency response toward 12 rv frequency r e­ the top end of the frequency range of 5 Ii ru ~~ sponse: the solid 0 1 most single unit loudspeakers. V curve represe nts ~ ~ Much of this can be smoothed out by ~ - 10 1/ incorrect termina­ ti o n, w h i le the careful attention to the compliance of '" V dotted one shows the diaphragm surround-the crinkled what co rrect ter­ part that allows it to move back and -20 minati o n in the forth freely at the periphery. Use of a TOO 1000 10000 ZUUJO FREQUENCY IN CYCL ES PER SECOND surround does. suitable impregnating compound pos­ sessing an appropriate combination of Levers are not used very much in pedances in series from the mechanical compliance and viscosity, provides a ter­ modern loudspeakers. The only types in viewpoint. One due to the behavior of minating impedance in the mechanical which they have ever been used are the the column in contact with the back of material of the surround which prevents moving iron and the crystal types. This the diaphragm, associated with the en­ reflection and hence avoids the break-up was because the driving force was pro­ closure, and the other in contact with effect. This method of treatment will do duced by an extremely stiff device that the front, which usually radiates out much toward flattening the upper end of was capable of large forces with small into the air. More -of this anon; mean­ the loudspeaker frequency response. movement. The lever helped to get a time this is somewhat of an oversimpli­ Figure 2 shows this. larger movement more suitable for driv­ fication, based on the assumption that A difficulty arises in the fact that the ing the diaphragm. In other words, it the voice coil is rigidly coupled to the properties of most of these impregnat­ helped achieve mechanical matching. diaphragm. ing compounds change with aging, and The reason why levers are avoided in This is not quite true. It is coupled hence the upper frequency response de­ the mechanical design of loudspeakers by material having certain mechanical teriorates as the diaphragm gets older. is that they are .not so easy to design properties and that is what we want Attention to the compliance of the with a wide frequency response as are spider or centering device attached to to consider immediately. The diaphragm electrical transformers. A lever to op­ the inner periphery of the diaphragm is not completely rigid, so the center erate equally well at all frequencies will also assist in controlling the move­ from 20 to 20,000 cps is a very difficult part, attached to the voice coil, can move ment, although this is strictly at the requirement to meet. in a manner somewhat different from the "sending end" of the transmission line outer periphery and the various other and appears merely as a series element Electromechanical Part parts of the diaphragm. in the driving force. Now let's see how the electromechani­ The easiest way to think of the trans­ If the loudspeaker is driven from an cal analogy helps us in understanding mission of movement from the voice coil, amplifier with a high damping factor,

38 AUDIO • FEBRUARY, 1961 • Individual AM and FM Electron ­ ALTEC 309A AM/FM Ray Tuning Indicators. • Softly illuminated Tuning Scale. • Decorative platinum gold or STEREO TUNER WITH platinum pink control panels. • Self,ventilating cabinet included in price. INTER·CHANNEL BALANCE • 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. • FM Local/Distant Switch assures proper input load for ALTEC 309A AM/FM STEREO TUNER 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 chan­ SPECIFICATIONS: nels. The result is balanced stereo at its best . .. yours to enjoy with minimum manual balancing FM and adjusting. Antenna: Standard 300 ohm­ The new ALTEC 309 A AM/ PM Stereo Tuner is a product of this latest AL TEC development. Maximum Sensitivity: 2 microvolts Because of Inter-Channel Balance, it offers important operating and performance advantages -Quieting Sensitivity: 2.9 micro· for stereo that conventional "two-in-one" combination tuners can't match. In the 309A, output volts for 20 db/7.0 microvolts for sensitivity through both channels is equalized for balanced reception of either local or distant 30 db-Frequency Range: 86.5 stations. The basic quality of AM performance is improved to match quite closely the inherent to 108 mc-Image Rejection: 45 quality of PM. Again, the result is balance-an ingredient that is essential to proper stereo db-IF Rejection: 55 db­ reproduction. Detector Peak Separation: 450 kc Truly, the new 309A AM/ PM Tuner is made for stereo-ALTEC stereo circuitry and design, -Frequency Response: ± 1 db ALTEC stereo Inter-Channel Balance, and convenient control facilities that are described at 20 to 20,000 cps-Antenna top right. The 309A is an exciting new tuner because it was developed by ALTEC specifically Radiation: Meets FCC require · for stereo operation. See and test the 309A at your ALTEC Distributor's today. A look and a ments. listen is all it takes! AM Antenna: Built·in Ferrite Antenna, BALANCED STEREO WITH' plus external antenna connection LOOK-A-LIKE MATES FROM ALTEC -Maximum Sensitivity: 3.2 ENJOY microvolts-Loop Sensitivity: 35 The popular ALTEC 353A Stereo Amplifier-Preamplifier is a desirable mate to the new 309A microvolts per meter-Frequency Tuner. Together, the pair represents a harmony of design and engineering; a perfect balance of Range: 540 to 1630 kc-Image components for a superb all-ALTEC Stereo System. . Rejection: 65 db-IF Rejection: The ALTEC 353A provides 14 stereo or mono inputs, 6 outputs; matricing network for 50 db-Selectivity: 6 db band­ 3-channel stereo; 100 watts stereo program peak power; 50 watts rms continuous, stereo or width: "Local" 13 kc, "Distant" mono; less than 1 % THD at 25 watts 1000 cps, each channel and less than 1 % THD at 20 6 kc - Whistle Filter: 10 kc atten· watts 30 to 15,000 cps, each channel; and frequency response ± 1.0 db 20 to 20,000 cps at uation better than 40 db. 25 watts, ± 0.5 db 10 to 30,000 cps at 1 watt. GENERAL ALTEC 309A AMi FM STE REO TUNER ALTEC 353A STER EO AM PLI FI ER· PR EAM PLI FI ER - $2 16 .00 INC LUD ING CA BI NET - $225.00 INCLUDING CA BINET Power Supply: 117v 60 cps 45 watts-Dimensions: 5'l's" H x I:.'I!ii33n ., , , . . • " • " " 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 Si xth Avenue. New York 13, New York AUDIO • FEBRUARY, 1961 39 Fig. 5. The effect +10 of the diaphragm arrangement of Fig. 4: the solid -" cu rve shows the "0 0 I ":::"" -- I--' 1-' 1" MAIN DIAPHRAGM fluctuation caused 5 by the transitio n 5 (, when successive 0 V 1/ ". rings become in­ ...~-IO a ctive; the dotted r line shows what ~ might be expected -20 if the transition 2 100 1000 10000 20000 were continuous. FREQUENCY IN CYCLES PER SECOND

(2) due to nonlinearity of the opposi­ There is another way of dealing with tion to movement, because the restoring this problem which consists of intro­ EXTRA DIArI"KA'bM-' force is not linearly proportional to the ducing corrugations into the cone at one FOR " HIGHS" deflection of the diahragm. This means that the movement of the diaphragm will or more poqts other than the periphery. not be uniform with the force applied This is then analogous to a lump-loaded to it. transmission line, in which the induct­ Special Diaphragms ance and capacitance comes in lumps in­ What is the effect of a small dia­ stead of being continuously distributed. This is illustrated at Fig. 4. Fig. 3. One kind of modification to a phragm attached to the same voice coil loudspeaker diaphragm that is designed inside the larger one, as at Fig. 3 , . There is a difference between this ar­ to augment the reproduction of higher From the mechanical standpoint this ad­ rangement and a transmission line: in frequencies. ditional diaphragm is not likely to pro­ this arrangement, energy can be radi­ duce any irregularities. It will vibrate ated by movement, represented by cur­ the voice coil will offer fairly high me­ as an entity at the upper frequencies, rent, in any part of the diaphragm j this chanical resistance to being moved by and so will not behave as a transmission is shown by resistance elements j III a the diaphragm, and hence the electrical line, like the large one. For this reason effect can be considered as equivalent to it will prove more effective for the radi­ a mechanical high impedance source. ation of the higher frequencies in the The effect of viscosity in the spidel' will band. As regards its effect on uniforDl­ --I merely add to the effective mechanical COMPLIANCE ity of movement at different frequen­ OF DIAPHR AGM source resistance. MAS S OF cies, it should have quite a lineal' per­ MOUNTING A IR LOAD Nonlinear Distortion formance because it exerts a uniform additional opposition force at the voice A more important feature of the RA DI ATI ON coil. Its principal effect will be that of spider is that its compliance should have RE SISTANCE increased effective mass at the voice coil. lineal' properties. The restoring force If it were attached at some point be­ should always be proportional to the tween the center and periphery of thc , deflection, otherwise it will distort the Fig. 6. Electrical equivalent circuit for the large diaphragm there would be a time movement of the diaphragm. low frequency resonance of a dynamic delay which would cause reflection de­ There are two possible causes of non­ type loudspeaker, not taking into account fects and irregularities in the frequency linear distortion in a loudspeaker: any effects due to an enclosure. response of the movement against driv­ transmission line, we usually consider (1) due to nonlinearity of the driving ing force. But being attached directly to force, because the magnetic flux in the only the energy reaching the far end, air gap is nonuniform. This will mean the voice coil former it should not pro­ which in this case is wasted in the sur­ that the same current in the voice coil will duce this kind of effect. However, it round. not produce the same force at all positions may produce irregularities due to acous­ At the lower frequencies, energy is ra­ in the gap, and consequently the driving tic effects in the air adjacent to the two force from the voice coil will not be uni­ diated from the whole diaphragm; at form with the electrical currents supplied diaphragms. This must be considered higher frequencies, the low-pass action to it. separately. of the line elements prevents transmis­ sion to the outer rings and all the energy is radiated from the inner section (s) . The effect of this system is to produce c4 a very gradual fluctuation in efficiency, represented in the response at Fig. 5.

c l ml +m2 rl Compared with Fig. 2, this is an im­ provement, but the uniform diaphragm 1 correctly damped can be better. To summarize then, the mechanical part of the loudspeaker has two prin­

B. cipal properties that contribute to its frequency response. These are: (1) A major resonance, due to the mass VOICE of the whole of the diaphragm and voice A, CO IL coil, together with a quantity of air that can be considered as moving with it, in conjunction with the compliance of the Fig. ~. Another method of improving the performance of a large diaphragm: (a) a surround and spider (neglecting for the phYSical cross-section through the voice coil and diaphragm assembly; (bl electrical moment the compliance of the air in con­ equivalent circuit. tact with the diaphragm).

40 AUDIO • FEBRUARY, 1961 "" " it's the newC&UOc0C&OO TR-30 TRI-ETTE* 3-WAY LOUDSPEAKER SYSTEM

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 . . 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

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GROUP II FURNITURE STYLES

TR-30 TRI-ETTE FEATURES NEW COMPONENTS o Featuring a new advanced-design 12" FlEXAI R* woofer with ..,:::::: 7 .,."M___ precisely ",,,,"," coordinated m,.""'" with ,,.the """,,," BASS-SUPERFlEX '"" '"",," * ~G· · '0."0 ~ r-. @) n C&DU<0C&DU MANUFACTURING COMPANY enclosure to carry bass down lower and better than ever . 0 .. . A WOIVISI ON OF THE MU TER C7' 6601 S. Laramie Ave., Chicago 38, Illinois before. Advanc ed deSign Improved compressiOn midrange :e:;. In Canada: Renfrew Electric Co., Ltd., Toronto and supertweeter units for smooth, balanced, extended , . 0 In Mexico: Universal De Mexico, S.A .. Mexico, D.F. response_ Be su re to see and hear the TR-30 _ •. you'll II make a wonderful discovery! Write for free illustrated Brochure" KU"

*T.M.

AUDIO • FEBRUARY, 1961 41 f will represent an increased dynamic im­ pedance. From this it will be found that the electrical equivalent must take the REFLECTED IMPEDANCE form shown in Fig. 7. This shows that the mechanical anal­ ogy 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 electromechani­ cal transfer. Fig. 7. The electrical impedance diagram, Similarly, looking at the mechanical showing the components reflected into arrangement the effectiveness of the the electrical circuit due to the mechani- electrical damping, provided by the cal resonance represented in Fig. 6. voice coil with a high damping factor Fig. 10. Cross-section of simple acoustical transformer, applied to a horn type loud­ amplifier, will also depend upon the elec­ These two major lumped components speaker unit. produce a low frequency resonance, the tromechanical efficiency. This means the equivalent circuit of which is shown at effectiveness of any attempt at damping mouth merely because of its compressi­ Fig. 6. by adjusting the amplifier damping fac­ bility. This air does not move appreci­ (2) At the high frequency end of the tor is definitely limited. ably-it just compresses and expands response the diaphragm tends to behave as a transmission line, causing some degree alternately. In the neck of the bottle, of breakup. The continuous type of trans­ Mechanical-Acoustical Coupling on the other hand, the air oscillates to mission line cannot readily be shown as an and fro, and hence the important feature We have discussed the factors control­ equivalent circuit, because it consists of about this "piece" of air is its mass. So an infinitely distributed mass and compli­ ling the relationship between the elec- ance, the configuration of which is similar the resonant frequency is determined by to that of a low-pass filter as at Fig. 4 considering the effective compliance of but when the number of inductances and the volume of air inside the bottle, in capacitances is infinitely large, and each conjunction with the effective mass of is infinitely small, the arrangement does not produce a low-pass characteristic, but the air that goes to and fro in the neck. a progressive phase delay which can be­ As a very small sound pressure at come several cycles by the time the ter­ resonant frequency will cause a big vol­ minating point, which is the periphery of the diaphragm, is reached. ume movement of air in the neck of the Irregularities at this end of the response bottle, the equivalent circuit is that can be minimized either by ensuring that shown at Fig. Sb, it is a series resonant the equivalent continuous transmission A. MASS OF AIR MASS OF AIR circuit. line is correctly terminated, by attention IN NECK I IN NECK 2 to the properties of the surround material Now suppose we have a container with or by the alternative lumped arrangement an opening at both ends and a volume of Fig. 4. SOUN ~SOUND of air enclosed as at Fig. 9. A sound PRESSURE ..l..COMPlIANCE PRESSURE OUTSIDE I OF AIR OUTSIDE pressure at one opening will have im­ Electromechanic-al Coupling NECK 1 _ INSIDE NECK 2 mediately next to it the opposing force The analogy circuit of Fig. 6 shows B. of the mass of ail' in the neck which the resonant circuit as a series one be­ Fig. 9. Bottle with two necks: (a) physical looks like an inductance. At the other cause this is the way the mechanical be­ cross-section; (b) equivalent circuit. end of this neck is the volume of air havior of the circuit works out, but the the compliance of which looks like a ca­ electrical characteristics as measured at trical driving force and the diaphragm pacitance. As the pressure of all the air the voice'-coil terminals will also be in­ vibration. The next thing is to transfer in the bottle is approximately uniform fluenced by the resonance. Because the the diaphragm vibration to the ail'. throughout, the mass of air at the other diaphragm movement is greater at this To see how these things work we need end of the space has the same pressure resonant frequency there will be an in­ to understand the acoustical analogy. at its input side as has the mass of air creased back e.m.f. in the voice coil which Here we make the sound pressure in a at the first neck on the inside of the wave correspond to voltage. The vol­ bottle. This whole volume is at constant ume movement velocity of air corre­ pressUl'e at any instant in time. sponds to current. The volume displace­ So the inside of both necks must be ment will correspond to charge. Acoustical resistance due to the vis­ MAGNET cosity of the air when particles have to move over some surface or one another, is equivalent to resistance. The mass, or SOUNDt;)MASSOF AIR IN inertia, of the air in movem'ent is equiva­ PRESSURE NECK OUTSIDE lent to inductance; while the compli­ NEC K ance, or compressibility of the air, is COMPlI- A NCEOF equivalent to capacitance. AIR IN­ These last two are the most important SI DE t ~ ones to understand and particularly is it B. important to grasp how they fit together Fig. 8. A narrow necked bottle, or Helm­ in an equivalent circuit. Consider a holtz resonator, ill ustrates the basic Helmholtz resonator-or just a bottle acoustical analogy: (a) a cross-section with a narrow neck-as at Fig. S. through the bottle; (b) electrical equiva- The air inside the bottle contributes Fig. 11. An improved type of acoustical lent circuit for same. to the resonant frequency excited at the transformer.

42 AUDIO • FEBRUARY, 1961 .THE ITATION "... FOR THE SAKE OF MUSIC AND SOUND~' OUR DEMANDING LOVE OF 11."

"Over and above the details of design and performance, shading stood out clearly and distinctly for the first time ... we felt that the Citation group bore eloquent witness to The kit is a joy to construct." the one vital aspect of audio that for so many of us has C. G. McProud, Editor, Audio Magazine elevated high fidelity from a casual hobby to a lifelong "The unit which we checked after having built the kit, is the interest: the earnest attempt to reach an ideal-not I'Ot' best of all power amplifiers that we have tested over the past the sake of technical showmanship-but for the suke of years." William Stocklin, Editor, Electronics World music and our demanding love of it," "Its listening quality is superb, and not easily described in Herbert Reid, Hi Fi Stereo Review terms of laboratory measurements. Listening is the ultimate A truly remarkable commentary about a truly remarkable tes t and a required one for full ~ppreciation of Citation .... group of products-the Citation Kits by Harman-Kardon. Anyone who will settle for nothing less than the finest will be Mr. R;eid's eloquent tribute to Citation is one of many ex­ well advised to look into the Citation II." traordinary reviews of these magnificent instruments. We are Hirsch-Houck Labs, High Fidelity Magazine proud to present a brief collection of excerpts from Citation "At this writing, the most impressive of amplifier kits is reviews written by outstanding audio critics. without doubt the new Citation line of Harman-Kardon ... "When we first heard the Citations our immediate reaction their deSign, circuitry, acoustic results and even the manner of was that one listened through the amplifier system clear back their packaging set a new high in amplifier construction ·and performance, kit or no." to the original performance, and that the finer nuances of tone Norman Eisenberg, Saturday Review

The CITATION I, The CITATION II, The CITATION III, Stereophonic Preamplifier Control Center 120 Watt Stereophonic Power Amplifier Professional FM Tuner The many professional features and philosophy Will reproduce frequencies as low as 5 cycles The world's most sensitive tuner. But more of design expressed in Citation I perm it the virtually without phase shift, and frequencies as " important-it offers sound quality never before development of a preamplifier that provides high as 100,000 cycles without any evidence of . achieved in an FM tuner. Now, for the first time absolute control over any program material with· instability or ringing. Because of its reliability Harman·Kardon has made it possible for the kit out imparting any coloration of its own . The and specifications the Citation II has been ac· builder to construct a completely professional Citation 1-$159 .95. Factory Wired - $249.95. cepted by professionals as a laboratory standard. tuner without reliance upon external equipment. The Citation 1I-$159.95-Factory Wired $229.95. 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

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, The CITATION IV, The CITATION V, New York. Stereophonic Preamplifier Control Center 80 Watt Stereophonic Power Amplifier All prices slightly higher in the West. A compact stereophonic preamplifier designed A compact version of the powerful Citation II. in the best Citation tradition. It offers perform· DeSigned with the same lav ish hand, it is can· ance and features rivaled only by Citation I. The servatively rated at 40 watts RMS per channel control over program material provided by the with 95 watt peaks at less than 0.5 % distortion. .CITATION ,KITS by new Citation IV enables the user to perfectly The availability of rated power at the extreme recreate every characteristic of the original per·' ends of the frequency ran ge enables the unit to formance. The Citation IV - $119.95 - Factory effortlessly drive the most inefficient speakers. Wired-$189.95. The Citation V-$119.95. Factory Wired-$179.95. .;&U"S,,' kardon I

AUDIO • FEBRUARY, 1961 Fig. 12. The acous­ good method adopted is the use of a +10 tica I effect of the number of channels to pick off the pres­ I diaphragm shown sure uniformly from different parts of in Fig. 3: the sol id the diaphragm 'and conduct the column -" ... 0 curve sh o ws t h e .!. '- of ail' into a single throat, as shown in . ,.~ \ response pro­ Fig. 11. This makes an efficient trans­ § ,F d uced, the d otted ::> former up to quite high frequencies, 0 / "'1 one the theo reti­ ~ ( whereas the abrupt change in size loses ;::- 10 cal effect of elim­ ~ V ina ti ng the aco us­ efficiency at the high frequencies due to '" tic a bsorptio n. The the capacitance effect of the cavity which dot-dash section it produces. -20 represents remov­ Another example of cavity effect can 20 100 1000 10000 20000 FREQUENCY IN CYCLES PER SECOND ing the small dia- occur with the diaphragm arrangement phragm. shown in Fig. 3. As it is not a deep cav­ ity-nor does it have a narrow mouth­ represented, in an equivalent or analogy former changes the ratio of voltage and its effect will not be very pronounced, circuit, by the same electrical point in current from one impedance to another. but it will result in a slight absorption the network. This means that the anal­ When sound is radiated outward over a fairly wide range of frequencies, ogy circuit of the whole arrangement freely, the air near the source moves as suggested in Fig. 12. looks like a low-pass "T" filter configur­ more, for the pressure fluctuation in­ Enclosures ation as at B in Fig. 9. volved, than the air further out. This But the thing which is of greater in­ means it has an inductive component From the acoustic response viewpoint terest in loudspeaker design is the con­ to its impedance. In fact a large pro­ it would not matter appreciably whether struction used for the lower frequencies portion of the inductance in Fig. 6 is the two necks were located at opposite -enclosures of various types. The bass­ due to radiation. This is why ends of the space, or next to one an­ the reso­ reflex enclosure operates in a manner nance of this kind of speaker has to be other, or in any other position, because similar to the container with a neck at the pressure inside will vary without ap­ at the low-frequency end. That way, a both ends, the diaphragm being placed preciable volume movement of the air. constant voltage, representing constant in one neck as the driving point, while sound pressure, is delivere.d to the in­ In practice there will be some slight dif­ the other neck is the vent of the enclo­ ference due to the fact that air does ductance-resistance combination. This sure. move to a small extent inside the space. principle is termed mass-controlling dia­ Figwre 13 shows the simplified analogy There is not a sudden transition from air phragm movement, because the principal diagram for a bass-reflex enclosure, as­ that moves to air that compresses. There reactance opposing movement is mass, suming that the volume is pure capaci­ is a small region where the air does both. throughout the audio spectrum. tance and the port pure inductance. In practice these assumptions are not quite Propagation Application true, but they do not seriously invalidate A sound wave propagated through air All of these simple acoustic devices the representation. This circuit shows in the form of a plane wave-that is, occur in loudspeaker design somewhere how the enclosure can damp the basic where the frontal area of the wave is or other. The acoustic transformer is resonance of the speaker by having the not expanding-presents a transmission utilized in horn-type loudspeakers to combined dynamic impedance consisting impedance that is characteristic, because match the diaphragm movement to the of the port, the volume of the enclosure, the pressure and velocity get passed on throat of the horn. Usually the dia­ and the radiation resistance, as a shunt unchanged, except for a slight attenua­ phragm is larger than the throat of the tuned circuit, damp the series tuned cir­ tion due to the viscosity of the air. horn as shown at Fig. 10. The air move­ cuit, consisting of front radiation re­ A continuous exponential horn above ment picked up from the diaphragm has sistance with the effective mass and its cut-off frequency looks like a resist­ to be compressed down to the size of the compliance of the diaphragm and its ance too. This is because the wave propa­ throat. associated components. It is possible for gates down the expansion and produces If any cavity is enclosed between the these two to be exactly complementary so a gradual transition, from high-pressure diaphragm and the throat, this will be­ as to damp out the mechanical resonance high-volume movement at the throat or have as a capacitance and cause a high­ of the diaphragm system. neck, to a low-pressure low-volume frequency roll-off by absorption. So, to If this was all that a bass-reflex en­ movement at the flare end. If the rate of minimize the volume of such cavity a closure did it would merely pull down 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 RADIATI ON means that the horn development looks M2 R2 like a constant resistance. Cl C2 Rl Ml A transition in area, from small to --IH~MNIr-f'/flll!lflf\ large, or large to small, through a rela­ M2 tively short distance, behaves as an acoustical transformer. In a narrow neck, VO ICE CO IL for instance, a high pressure with a FORCE given volume displacement, on reaching R2 a sudden expansion encounters a sudden

freedom of movement which causes the B. pressure to drop. At the same time the volume movement is allowed to increase A. at this point. So the step in area ex­ Fig. 13. The action of a bass reflex enclosu re is somewhat similar to the bottle with changes one ratio of pressure to volume two necks of Fig. 9: at (a) a cross-section through a bass refl ex e ncl osure; (b) the movement for another ratio, like a trans- equivalent circuit.

44 AUDIO • FEBRUARY, 1961 AN AM:PEX FOR EVERY PROFESSJ:ONAL NEED

In sound qu.ality, , , in features, , , in lasting economy. , , these four Ampex professional re­ corders 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 THE PR-10-2. MONOPHONIC, STEREO/MONO Full or half-track. Single-channel Two-channel electronics fit some electronics in~lude built-i n mi xer rock space as PR -10-1. Po rtable to mix line and mike or two mikes for remote pickups as well as in­ Iwith plug-in pre-amp}. Portable, st udio use. Split erose permits or fit s 14" of rock space. 3'/, and stereo recording, half-t rack mono 7'/,; or 7 '/, and 15 ips speeds. recording, cue track , and sound­ Exclusive self -thread ing option. on-sound. Two line inputs can· Ali gnment controls in front panel. vertible Iwith pre-amps} to two New frict ionless tope handling. mikes - one pe r channel. Addi ­ AII-el eelri c push.button controls tional mike and line inputs pos­ permit remote co ntrol operation. sible with MX-10 mixer. Write for Write for Bull eti n 212. Bulletin 212 .

10Y2/1 REELS THE AMPEX 351 THE AMPEX 354. MONOPHONIC STEREO/MONO Available in full or holf·track Two ·chann e l e lectronics .. Co m­ models. Input switchable to mike, pael and portable version as well balanced or un balanced line. as console. ,Requires c;ml y some To kes reels from 3" to 10'/,". rock space as 351. Some heavy Speeds: 3'/, and 7,/, or 7 '/, and duty tope transport as 351.. Two 15 ips. Available as console, two­ line inputs, convertible to two ·case portable or mounts in 22%" mikes lone per channel} with pre­ of rock space. AII·electric push­ amps. More mike and line inputs button controls permit remote w ith MX·35 mi xer. Convenient control operation . Lorge 4" VU. balancing of stereo-channels with meter reads input or recorded side-by· sid e VU me ters. Split level plus bios and erose current. erose for stereo recording, half­ For more information, write for track mono, cue tro ck , sound-on­ Bulletin 203 . sou nd. Alignment controls in front panel. Bulletin 208.

ACCESSORIES AND ASSOCIATED EQUIPMENT I iAMPEXI MONITOR SYSTEM STEREO/MONO MIXER PLUG-IN EQUALIZERS PLUG-IN INPUTS SA-lO, Console quality, 40 MX-10 or MX-35, Four posi - provid e NAB AME o r CCIR match va ri o us inputs. Bal- watt speaker-amplifier unit .. tion, two channels, matches curves as required. anced bridgi ng or mikes. Portable, rock or wall PR -10 or 351/354. mounting. Bulletin 214 .

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 range. Above the low-pass cutoff fre­ +10 quency the diaphragm loses its rear load­ C i-- A ...... r--- ing, allowing it to radiate from the front V Fig. 14. Action of side. So the result is, that frequencies / ~ a bass-reflex en­ closure. A is the above the chosen crossover, which may ..,Jf J \1 ~ ~ be, say, 200 cps, are radiated directly J. curve of the unit 12 I / ~ ~ without an enclo­ from the front of the diaphragm, while 5 ...... t-- / I--- sure; B represents frequencies from 20 to 200 cps are radi­ ~O II the effect of the > ated via the acoustic horn, This is illus­ ;= ./V- enclosure in pull­ trated at F ig. 16. In this case, the length ing down the ~ DV/ ~ of the horn and the position of its mouth '" --- peak. must be adjusted so that the radiation is , ~ V II in phase from back and front of the dia- 20 JO 40 50 60 80 '100 200 300 400 500 '600 FREQUENCY IN CYCLES PER SECOND the peak at the low-frequency end of damps the resonance. An analogy circuit the loudspeaker's response curve with­ is shown in F i g. 15. In this wayan ex­ Cl M2 out extending the frequency range any tremely smooth low-frequency response t'\1 lower down, as in Fig. 14. But the addi­ can be obtained. Rl tional mass (inductance) of the port, This is just one approach to the prob­ lowers the resonant frequency, without lem and it involves the use of one of the having to make the diaphragm mass too newer special type loudspeaker units, great for good operation at higher fre­ with extremely high compliance, so that quencies. the diaphragm appears to be very floppy. At the mutual resonance of the system These units can only be used in such the radiation from both the diaphragm enclosures, otherwise they would rapidly and the port is in phase. This can be damage themselv'es. appreciated best by thinking of the reso­ Other approaches to the low-frequency nance of the bottle with two necks. Al­ problem use all kinds of enclosures with though the energy is excited in one neck, labyrinths and folded horns. In the case due to the fact that the air inside the of a folded horn, the objective is to bottle compresses and expands as an en­ maintain a correct exponential rate of tity, the air flow in the two necks will expansion during the folding of the ex­ be almost exactly in phase, there being panding channel in different directions. just a slight lead in the one providing This w'ay effective transmission is the drive. This is in fact what happens achieved without the need for the exces­ FRONTOFl with a vented enclosure. sive length necessary in a straight horn DIAPHRAGM In the case of the latest type of low­ development. r frequency reproducer the mechanical Some units use a folded horn develop­ construction is made with a very large ment from one side of the diaphragm, compliance, so that the natural resonance usually the rear, with a built-in acoustic ~~r is extremely low (this is when no enclo­ low-pass filter, using a large cavity for sure is used). Then the size of the en­ the capacitance and a slot for the be­ B, closure, which is sealed and not vented, ginning part of the horn as an induct­ is adjusted so that the over-all compli­ ance. This makes the horn useful for Fig. 16. Another kind of low-frequency ance of the diaphragm and that of the only a comparatively narrow range of system, using a folded horn and acoustic low-pass filter: (A) a simplified physical enclosure produces a resonant frequency frequencies between its own natural cut­ diagram (in practice the horn is folded, at the extreme bottom end of the audio off, which is very low, and the acoustic to save space); (B) analogy diagram. The spectrum- where it should be. The in­ low-pass filter cutoff. The entire ar­ value of r2 is much greater than rl' so terior of the cabinet is treated to pro­ rangement provides loading for the rear that for frequencies below the acoustic vide an acoustic resistance effect that of the diaphragm in this frequency low-pass filter (c 2 , ma) rolloff the major radiation is from the horn. Above this

frequency r2 ceases to be coupled, so the major radiation is from rl , m2 • The physi­ cal disposition of the horn mouth and diaphragm must be such that, at the CI Ml M2 chosen crossover, the energy from both -I emerges in phase. phragm at the chosen crossover fre­ quency. This is just an example. To give details of every enclosure sys­ tem 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 B. ested can figure out how any particular loudspeaker system has been engineered to get the desired results. This knowledge Fig. 15. A comparatively new method of handling low-frequency response: at (A) a will then prove helpful in judging to , what extent the design is successful in cross-section; at (B) an analogy diagram, Cl is several times as great as C2 so that the laffer becomes the controlling compliance. achieving its objective. .IE

'46 AUDIO • FEBRUARY, '1961 UNDISTORTED SOUND ••• ABUNDANT POWER

PIONEER MODEL SM-B180 AM-AM/FM STEREOPHONIC AMPLIFIER

Now available is a new PIONEER stereophonic amplifier, Since the SM-BISO is designed for use in conjunction with the model SM-BISO_ crystal or ceramic type pickup cartridges, simple handling is another of its many outstanding features, yet despite this, Providing exceptional tonal "quality, the two channels of this its performance will satisfy the most critical ears. stereophonic amplifier each employ a pair of 6BMS (ECL-S2) type tubes. Whether it be reception of stereophonic broadcasts or playback of records, the SM-BISO is the amplifier for you, Each channel has a rated power output of 10 watts, ample the amplifier that provides superb stereophonic reproduc­ power for home applications. tion for your listening pleasure.

A TRANSISTOR PREAMPLIFIER, THE PIONEER STP-l, that facilitates use of low-output magnetic cartridges in conjunc­ tion with amplifiers designed for crystal or ceramic cartridges ...

* Can be used if the output of your cartridge dry batteries used in transistor radios is anywhere between 2.5 to 35 millivolts; available anywhere; * Is equipped with two independent channels, * Extremely low current drain-battery will and so it may be used for both monophonic last as long as six months in normal and stereophonic applications; oPeration; * Has exceptionally low distortion and virtually * Extremely simple connections; no noise; * Recommended for use in conjunction with * Operates from standard 9-volt laminated PIONEER's SM-BISO or SM-Q140 amplifiers.

FUKUIN ELECTRIC, LIMITED - 5 Otov-.:acho 6-chome, Bunkyoku, pioneer Tokyo, Japan

AUDIO • FEBRUARY, 1961 47 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 Ea UI PJ'J\ Ef'l ~r 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 Ilttt:ttt'ttttd p showing which circuit is in operation. The u "'" !: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 PROfilE and the FM control is at the upper right. SARCENT-RAYMENT SR-8000 The SR-SOOO combines an FM tuner, an Using the built-in ferrite loopstick on AM tuner, and a complete stereo preampli­ AM, the sensitivity is rated at 20 ~v; for STEREO TUNER-PREAMP AND fier in one chassis. The AM tuner section is 20 db quieting, the sensitivity on FM is SR-202 REVERBERATION UNIT practically the same as the AM section in loS I!kV, Harmonic distortion measured at the SR-1000, and consists of a 6BE6 mixer­ less than 0.1 per cent on either AM or FM The basic difference between high-quality at 1 volt output, with 1M distortion O.lS preamplifiers resides in the fundamental oscillator and a 6BA6 i.f. amplifier stage feeding the patented Sargent-Rayment AM per cent on FM and 0.22 per cent on AM system philosophy underlying the design, at the same output. for any engineer worthy of the name detector, which has a very low distortion. should be able to design an amplifier which The SOOO employs two germanium diodes Bass controls provide a boost of 14 db is equivalent to any other amplifier, as far as the second dete~tor, resulting in a sav­ at 50 cps and a cut of 16 db at the same as performance is concerned. Almost the ing of space as compared with the SR-1000. frequency. The turnover point of the con­ same statement applies to tuners, either Both models used i.f. transformers with trols is at 350 cps. The treble controls gave AM or FM, and the basic difference be­ tapped secondaries connected to switches a boost and cut of 10 and 14 db respec­ tween the performance of two different to provide narrow or broad-band reception, tively at 10,000 cps, with a turnover at lS00 tuners can be determined almost by the with a resultant improvement in the high­ cps. Phono equalization measured within pl'ice, tag alone. It is very unlikely that freqnency response when in BROAD. 1 db of the RIAA standard, and the tape some one manufactUl'er has found the The FM sections differ considerably in head input measured within 1 db of the secret of making a piece of high-quality detail, though not in philosophy. The SR­ NAB characteristic from 30 to 7000 cps­ equipment at a cost differential of much SOOO employs the inductance-tuned dual above which frequency it increased ap­ more than 10 per cent below another. triode circuit originally developed in Eu­ preciably over the standard, presumably to Sargent-Rayment equipment has never rope and furnished as' a separate and com­ give the needed boost for recorders with been low priced. Neither have Cadillacs­ pletely self-contained cartridge. A.f.c. is insufficiently narrow head gaps. For a at least within the memory of most of provided by the use of a voltage-sensitive I-volt output, a signal of 0.S7 mv was re­ you. (There was a time when Fords cost diode in series with a small capacitor and quired at 1000 cps on the phono inputs, $900 and Cadillacs cost $SOO, but that was controlled from the ratio detector circuit. and 1.6 mv at the tape head input. For around 1909.) But if it has not been low Two i.f. stages and a single limiter serve auxiliary inputs the equivalent input sig­ priced, it has at least been of high quality. to feed the detector stage which employs nal was measured at .057 volts. When We have reported in these pages the SR-6S, two diodes in a wide-range ratio detector powered by SR amplifiers, the signal-to­ an AM/FM tuner; the SR-5S, AM only; circuit. noise ratio measured 72 db on phono and and the more recent SR-1000, an AM-FM­ The outputs of the two tuners are fed tape-head inputs and 61 db on the high­ stereo tuner of superb listening quality. to the selector switch of the control unit, level inputs. Tracking of the volume con­ Barring the now defunct t.r.f. tuners gen­ as are the ouputs of the two equalized pre­ trol was measured at ± 3 db over the range erally following the design of the old amp stages which acco=odate magnetic from ma... dmum to 40 db down; of tone Western Electric 10-A Radio Receiver, it pickups and tape heads. These stages use controls ± 5 db over the same range. As is probable that the SR-1000 had better 12AX7's with low-noise resistors in the noted, the SR-SOOO is not self powered, but AM quality than most anything else on the plate circuits of the first stages. Following must have plate and heater supply from market. The SR-5S was better, but with the the selector switch are the SEPARATION con­ some other source. All SR basic amplifiers great increase in FM listening, AM re­ trol, the REVERSE switch, and the BALA:!:,CE are equipped with power output sockets ceivers have become almost as obsolete as control. These are followed, in turn, by the which will supply the required power' for 24A tubes. tone controls which feed the pentode sec- 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 r 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 I reception, it is necessary that the listener be within 20 miles of the transmitting sta­ tion, and it is rare that good FM reception is reliable 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 SR­ SOOO-as well as many other SR units-is that they are powered from the main am­ Fig. 1. Sargent-Rayment Model SR-8000 AM/FM stereo tuner 'and preamplifier. plifier and therefore do not have any heat

48 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 the slightest impulse - effortlessly follows the spiral responsive transcription arm ever designed. So pre· course of the record groove, favoring neither one wall cisely calculated is the distribution of arm mass, and nor the other, and responding smoothly to the rise the location of pivot points in the center of mass, that and fall of even the most badly warped record. The 98 when statically balanced in one plane, the 98 is in will track a record groove at any angle of turntable balance in all planes. tilt- on its side, or even upside down. Even the application of stylus force' doesn't disturb You owe it to yourself to see the Empire 98 in action, the arm's stability. An adjustment knob - calibrated and hear how much better any cartridge sounds in an in grams - is dialed to the stylus force desired. This arm that permits the cartridge to give its best per· action tightens a spring coiled around, and secured to formance. Visit your hi·fi dealer today, and ask him the vertical pivot shaft of the arm. This exerts a torque about the Empire 98, 12" $37.50; Empire 98P, 16", or twisting force on the shaft which, in turn, increases $44.50. the force of the stylus without shifting the arm's center TRULY COMPATIBLE MONO·STEREO CARTRIDGE of mass, and without upsetting its dynamic balance. ' Empire 108 ... first to achieve high fidelity reproduc· Yet, for all the rock·steady stability of the Empire 98, t!bn from stereo and monophonic records. its lateral and vertical compliance is almost incredible. Both pivot bearings are suspended in precision ball Er;npire 108 with .7 mil diamond stylus $34.50 races, so finely balanced that the arm responds to Empire 88 with .7 mil diamond stylus $24.50

FREE a "Do·lt·Yourself" stereo/ balance kit actively demonstrates

1075 STEWART AVE •• GARDEN CITY. N . Y . scientific principles of balance-ask your dealer. EXPORT : EMEC. P LAINVIEW . N . Y . CANADA : ACTIVE RADIO &: TV LTD •• TORONTO Z . ONT.

AUDIO • FEBRUARY, 1961 49 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 reverberation is applied to either channel A or channel B, the other being normal. Some reverberation units using the H am­ mond device have been demonstrated with too little "straight-through" signal, so that •• the unreverberated signal is relatively 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 that addition of the reverberation does not appreciably affect the over-all volume, t~e effect is pleasing and the H ammond umt Fig. 2. SR-202 reverbe ration unit incorporates the Hammond de lay unit may be said to be performing excellently and the Sarge nt-Rayme nt e lectron ism. ' - better, in fact, than many devices costing several times as much. or hum problems from the built-in power a period of time, and the delay times of The design of the electronic package of supply. There is something to be said for the sections differ-one being in the vi­ the SR-202 is such that it is not probable either system, but it seems that there cinity of 28 milliseconds and the other that the listener will get too much rever­ might easily be adequate power available around 37 ms. In the SR system, the two beration. We find the over-all effect pleas­ from almost any main amplifier to feed the outpnts from the preamp are combined to ing with the addition of small amounts of relatively low power requirements of a provide A + B signal which is fed to the reverberation-so much so that we have tuner-preamp, and the elimination of the driver transducer. The output from the installed the b asic idea into our reference a.c. circuitry from the preamp chassis is driven transducer feeds the two channels system, with some modifications, of course. definitely an advantage. simultaneously. The actual circuitry con­ For the technically inclined, the driving sists of two 12AX7's and a 6DJ8-all signal f eel to the Hammond unit . should SR 202 Reverberation Unit being dual triodes. The inputs are fed to be in the vicinity of 5 volts, approxlIDately the two grids of the first 12AX7; their - in any case, it should be enough so that The reverberation units which have ap ­ outputs are combined and fed to one sec­ the signal-to-noise ratio does not suffer in peared on the market during the last year tion of the 6DJ8, which f eeds the driving the reverberation circuit. But under proper are all alike in the basic principle of opera­ transducer. The delayed output from the conditions of operation, the device works tion, althongh there is considerable differ­ springs is then fed to the second section wonderfully, and with judicious control ence in the electronic circuitry which ac­ of the 6DJ8, thence to a "volume" control makes an interesting addition to any hi-fi tuates the H ammond unit which is the with the arm circuitry being split to the system. B-26 heart of all the systems. The SR-202, shown two grids of the second 12AX7. The un­ in Fig. 2, employs the H ammond unit with reverberated signal is fed from the first the small electronic package which is to t he second stages by a resistor coupling SHURE STUDIO DYNETIC pewered from either the main amplifier or the two cathodes. Thus a certain , fi."{ed STEREO PICKUP AND ARM a separate power supply such as the SR- value of "direct" signals from the two 900 or SR-9000. channels goes straight through, while a There is much to be said for the inte­ The Hammond unit, which consists of controllable delayed output of the sum grated arm and cartridge, for the manu­ two coil spring assemblies, each driven at signal is fed simultaneously to the two facturer is then able to adjust the charac­ one end by a common transducer, with the channels. teristics of the two elements to each other delayed souud being picked up at the other In the SR model, there are four positions -much in the same manner as when a loud­ end of the springs by a similar transducer. of the control switch-OFF, in which the speaker and enclosnre are engineered by The individual spring assemblies consist output of the preamp is fed directly to the the manufacturer to complement each of two sections, wound ill opposite direc­ power amplifiers and the heater current is other. I n 1957, the first Studio Dynetic tions so as to preclucle "u nwindin,g" over switched off; REVERB. in which t he signals cartridge-and-arm made its appearance, .- and we reported on the combination at that time (AUDIO, May, 1957) . Since then we have continued to find the performance of the original pickup/arm combination prac­ tically faultless. The stereo version of the Studio Dynetic was bound to appear, of course, and on outward appearance there is little differ­ ence. The arms are counterbalanced in the same manner, with the counterbalancing weight being supported on a spring steel strip which is damped to eliminate the low­ frequency resonance which is usually en­ countered in the 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 adjustable stylus force between 1.5 and 2.5 grams. The ca.rtridge is raised or low­ erecl by pressing a plastic button on the top of the arm, but it is almost as easy to slide the styIns across the record to the de­ sired point without raising it (though this is not 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 con­ tacts 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 paralleling the two amplifiers with no change in s\vi tching being required. The Fig. 3. Shure Studio Dyne t ic integrated stereo cartridge and a rm. Arm ta kes either sleeve of the mounting carries the common stereo or mono cartridges. ground terminal on the stereo pickup, as

50 AUDIO • FEBRUARY, 1961 ® STEREO SPEAKER SYSTEMS * The exciting sound of the new Scott "Reflec­ Use any Scott tion Coupler" Stereo Speaker System has al­ bench with cushions ready made its mark on the world of music or reproduction. Hi-Fi enthusiasts-even the most skeptical-have come away from demonstra­ without tions convinced that this system is the answer or as a planter or to many of the limitations of stereo as repro­ as a combination duced by direct radiator speaker systems. bench and planter The Scott system is based on a wholly new Use a cabinet design in which the sound is reflected off the * for record floor and walls, eliminating any point source rr--,,,,,,,,,,,,,,, of sound. The wall against which the system is hi-fi playing becomes the sound source, just as the equipment or '---f~=11 stage is the sound source in a live performance. for linen, glass, The stereo effect is fully dimensioned as to spread and depth. and height, with no gaps in silver or china; the sound. And the stereo effect is the same or as a cellarette everywhere in the room, eliminating the need for "front and center" listening. However you use the Scott Speaker System, you never see it. It is truly "the invisibJe Have you heard the Scott "Reflection Coupler" speaker system." Stereo Speaker System? No one can describe Many fine audio and music stores are no:w how a speaker system sounds. You really must featuring the SCOTT "Reflection Coupler" hear it for yourself. Once you have heard the system, we have some other exciting surprises Speaker System. Write to Dept. B-2, SCOTT in store for you. Radio Laboratories, Inc., 241 West Street, Annapolis, Md., for a descriptive brochure, Due to its unique design, the Scott Speaker price list and the name of your nearest dealer. System has more versatility of application than any other speaker system. It can be placed out "The sound of Scott is the sound of music" of sight under or in back of other furniture. In the authentically designed, hardwood Scott SCOTT RADIO LABORATORIES, Inc. Custom benches and cabinets, the possibilities are endless. Here are some of the ways you can 241 WEST STREET, ANNAPOLIS, MARYLAND use the system- • Patent Applied For AUDIO · . FEBRUARY, 1961 51 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 +1 0 of the stepped surfaces is slightly crowned so that when the finger pushes the moving +s -" belt, the crown helps it work its way to the "I 0 ~ other step. This system works well unless • 1,..00' Fig . 4. Measured thE> belt stretches . 5 -s ....D. output of Shure The 440 uses a 4-pound turntable simi­ :> V 0 - 10 ~ Stud io Dynetic car­ lar to that on the Fairchild model 412. V --- tridge (solid li ne) This turntable is balanced and rides on ~ - 1S .... .,.1'" I an d separa t ion a micro-finished ball-thrust bearing in a ~ - 20 s~p~~~~b~ - (dotted li ne). nylon seat. The main shaft is micro-honed '" ~ and rotates in a polished babbitt bearing. - 25 ~ '" 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. 20 , . 100 1000 10000 '0000 Although this is not an accurate test, we FREQUENCY IN CYC LES PER SECOND have beeu doing this on similar rotating equipment for years, and find it a good rule-of-thumb indicator for rotational per­ well as one of the output circuits on the laterally. Thus, for truly fine stereo per­ formance. On this score the Fairchild rates mono unit. formance, a turntable must have very low excellent. Figure 3 shows the M216 model, which rumble. Of course wow and flutter must All controls of the 440 are located on the has an over- all length of 14%, in.; M212 is also be exceedingly low, but these prob­ top of the monnting board and include a a shorter model with an over-all length of lems were solved satisfactorily in mono­ speed control as well as an on-off switch 11-5/16 in., and is perfectly suitable for phonic days. An interesting note here is and the speed-change lever. The speed con­ the usual home turntable. The bearing on the' strip chart that is supplied with the trol can vary turntable speed by as much the vertical axis of the arm is a ruby, pro­ model 440. It is a recording of the final as Ph per cent. It does this by applying viding a minimum of friction; the car­ test for wow and flutter on the specific d.c. to the motor windings. tridge is carried on two additional ruby unit. The interesting aspect of this, aside The test chart provided with the turn­ bearings (actually four separate bearings, from the superb performance recorded, is table is ample proof of the practically un­ since there are two sleeves and two caps). that Fairchild is so confident of its manu­ measure able amount of wow and flutter in Compliance is claimed to be 9 x 10'" cm/ facturing skill as to provide the actual test this t urntable. Nevertheless we tried a dyne, which is relatively high. The output performance for each turntable it makes. listening test using several records reserved per channel, feeding into a recommended The 440 makes a rather handsome pack­ especially for this purpose-piano records load impedance of 47,000 ohms, is approxi­ age mounted on the special mounting board for wow and violin performances for flutter mately 4.5 mv for a stylus velocity of 5 and base available as optional extras. In -and confirmed the results of the test cm/sec at 1000 cps. Figure 4 shows the addition, the mounting board is isolated chart; neither wow nor flutter is detectable measured response from a test record cut f rom the base by means of four special to the ear. Rumble, both lateral and verti­ with constant amplitude up to the turn­ rubber feet; the board just rests on these cal, is 56 db below 7 cm/sec at 500 cps. over frequency (500 cps) and at a constant feet, held down only by the ""eight of the The 440 achieved operating speed within velocity above turnover. The two channels components mounted on it. The visual ef­ one revolution as verified by the strobo­ measured within 0.8 db of each other fect of this arrangement is a little dis­ scopic disc supplied with the turntable. throughout the range indicated. Separation concerting at first because, until one ex­ One minor annoyance with this type of is greater than 25 db · at 1000 cps, and at amines it more closely, the mounting board disc is that a fluorescent or neon light no place is it poorer than 10 db. seems to be floating above the base. source should be used, and such sources are One of the features of this arm-cartridge Speaking of mounting, the entire mecha­ not always easily available where the turn­ combination that attracts us most is its nism- motor, turntable, controls, etc.­ ta ble is located; it wasn't in our particular ability to track the record groove when are monnted on a rigid U-channel which, situation. used in a typical pull-out drawer turntable in turn, is attached to the board. The In operation in our listening area, using mounting. Several types that we have tried motor mounting is isolated from the turn­ the Fairchild mounting board and base, would j ump out of the groove as the drawer table to avoid rumble. The use of the there was no acoustic feedback discernible. was opened or closed; these were especially U-channel makes installation of the 440 a In addition, it is extremely handsome. We susceptible to vibration of the floor as one rather simple procedure. It took us about are often willing to forego appearance for walked (or jumped up and down) in front 3 minutes with Fairchild's mounting board. the sake of performance, but it is all the of the cabinet. (We can see no reason for A feature of this turntable is that it is more enjoyable when we can have both. It j umping up and down in front of the cabi­ belt-driven-and two-speed. The speed will soon be available in kit form. B-28 net, 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 with­ out a great amount of care being required. While most modern cartridges measure reasonably well, there is often some differ­ ence is sound quality that the measure­ ments do not show up-Which only indi­ cates 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 FAIRCHILD 440-2 TURNTABLE The Fairchild model 440 is a 2-speed belt-driven turntable designed to provide performance suitable for the rigorous de­ mands 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 Fig. 5. Fa irchild 440-2 two-speed belt d riven turntable.

52 AUDIO • FEBRUARY , 1961 plus unique program flexibility for the whole family ...

vvilh Ihe RP-40 SOUNCSPAN RECEIVER

Hi-Pi requirements differ ... often within the same family. Dad, A Imiqtte Home Music Center .•. the RP-40 features: Illuminated the audiophile, looks for a high-fidelity receiver that meets his Tunetabs for quick tuning; Variable Blend-Control; Power technical standards. Mom and the kids may want Bach, "Rock", Doubler Switch; Precise-acting Automatic Gain Control; Special or the ball game ... often at the same time. Mono! Stereo Switching Circuit and many other valuable facilities. Now-ONE unit answers ALL family needs ... the exciting BOGEN-PRESTO RP-40 Receiver with SoundSpan combines RP-40 Specifications: Frequency Response - Idb, 18 to quality and flexibility. It's an FM-AM stereo receiver of 30,000 cps; Output - 20 watts per chandel, 40 watts com­ unsurpassed performance, with SoundSpan - the revolutionary bined; PM Sensitivity - 0.9 p.y for 20 db quieting; AM development that makes it possible to channel any two different terminal sensitivity - 1.2 p.v for .5v output; Distortion­ monophonic programs simultaneottSly - or one stereo program less than 0.8% at full output; Hltm Level- -80db; Dimen­ - to several loudspeakers located anywhere in the home! sions-16" x 13Yz" deep x 6". Owning the BOGEN-PRESTO RP-40 with SoundSpan is like having two independent, top quality, high-fidelity systems in your home RP·40 Receiver with SoundSpan $329.50, -for the price of one! It's today's Finest Component System­ less enclosure. Slightly Designed for Tomorrow's Needs! Write today for free literature. higher in the West. BOGEN-PRESTO =. Desk A-2 - Paramus, N. J .• A DIVISION OF THE SIEGLER CORPORATION : - 60·21 AUDIO • FEBRUARY, 1961 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 manufactur­ ing FM tuners. Of course, being old cynics, and having built many an FM tuner kit in the past, our first reaction was to disbelieve what we were seeing. We couldn't prove it but we were convinced, within ourselves, that these two builders were really tech­ nicians in shapely clothing. Perhaps this is just our own personal reaction to all the superlatives we encounter nowadays. Anyhow, since that time we have con­ structed the LT-10 ourselves-and most humbly apologize for our base thoughts_ Fig . 6. Completed H. H. Scott model LT-' 0 FM tuner kit. This kit is the simplest to build we have seen to date. It took us less than 7 hmtrs impressed by the relatively large numbers 1'he really different feature of this cir­ to put it together, and that includes align­ involved. cuit, as we mentioned previously, is in the ment_ In addition, since completing this F'ig1tre 6 shows the L'r-10 completely detector stage. In co=on with all of the unit, we have operated it almost continu­ assembled in its case (not supplied with H. H. Scott FM tuners, the LT-10 uses a onsly for nearly three months without even kit). The tuning meter shown on the left ratio detector. One of the advantages of the a hint of difficulty. Without hesitation, we front is quite sensitive and is illuminated ra tio detector is the additional limiting it would reco=end the H. H. Scott LT-10 so that it is easy to read at night. The provides. Another, and probably the great­ FM tuner kit to the beginner as well as the tuning dial is also illuminated and un­ est, advantage is the wide bandwidth ob­ more experienced audiofan. usually easy to read. At night the edge-lit tainable. The 2-megacycle bandwidth of Before continuing, we should mention plastic tuning dial is handsome as well as this detector is, to a large extent, respon­ that in the realm of kits the H. H . Scott functional. It should be noted that the sible for the freedom from drift of this LT-10 exemplifies engineering of the high­ action of the tuning dial is extremely tuner. For this reason the LT-10 does not est calibre. Surely only the most sophisti­ smooth and sensitive, although just a shade provide a.f.c.-nor do any of the H_ H. cated engineering thinking could design too sensitive for our taste. We like a little Scott tuners_ From our experience, it is not a kit as simple and foolproof as this one is. more positi,'e feel. In comparison, it is like needed. Although virtue is said to be its own re­ the power steering employed on Chrysler Although it doesn't actually pertain to ward we do hope that such excellence re­ cars as contrasted to that used by General circuitry as such, a great deal of attention ceives appropriate recognition. Motors. We prefer the more posith'e feel has been paid to reducing circnit losses. Up to this point we have confined our of the GM type. Tllis is evidenced by the silver-plated front discussion to the LT-10 as a kit. In reality end and the copper-bonded-to-aluminum there is a more fundamental question to be Circuit Description chassis. Details such as these permit the answered, "How good a tuner is the LT- circuit to operate at its full capability­ 10'" To put the answer in some frame of In most respects the circuit of the LT-10 precautions which are especially important reference we will point out that the LT-10 is completely straightforward: cascode r.f. ill r.f. circuits. is essentially a model 314 in kit form. That amplifier utilizing a 6BS8/6BQ7 A; 6U8 makes it a good FM tuner. It utilizes the oscillator-mixer; a pair of 6AU6 i.f. well-known silver plated front end and the stages; and a limiter consisting of the pen­ Alignment wide-band circuitry which is a f eature of tocle section of a 6U8; the detector, which Alignment is the most difficult stumbling all H. H. Scott tuners. During the several is the unusual feature of this circuit, uses block facing the audiofan who builds an months we have had it in operation no less a pail' of 1N294 diocles; and the audio out­ FM tuner kit. Precise alignment requires than ' nine different people-guests-have put is the triode section of the 6U8 limiter the use of various types of test equipment had to be shown that an FM tuner was the used in an anode-follower configuration. which are not usual audiofan gear-an FM music source, and not a record. We should The anode follower here provides some ad­ signal generator and an oscilloscope to mention that it is not common practice to ditional gain and permits cables up to 70 name some. There have been many schemes count guests in our home-but we were feet in length. 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 Sissy's giggles, for instance.) _ Remember: if it's her funny bone-and out comes the purest, merriest worth recording, it's worth Audiotape. There are of sounds. _ We don't propose there's anything quite eight types . .. one exactly suited to the next recording as nice. But we can tell you about another kind of you make. 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 GlIcl.iotae,!' than other tapes, because it's made to professional " IT SPEAKS FOR ITSELF" standards. Let it be your silent (but knowing) partner AUDIO DEVICES INC., 444 Madison Av e. • N. Y. 22. N. Y. in capturing fresh, clear, memorable sounds. (Like Hollywood: 840 N. Fairfax Ave., Chicago: 5428 N. Milwaukee Av&. these are minimwnn specifications. It should ERCONA NORDIC be noted that H. H. Scott adheres to IHFM SPEAKER SYSTEM ratings. For example, a usable sensitivity of 2.5 microvolts is claimed. Some other If we weren't already cOllvinced, this manufacturers use a different rating sys­ diminutive speaker system would certainly tem which makes it seem that their tuners prove that size isn't everything. When we are more sensitive. In reality, if the same first removed the Nordic I from its packing conditions were used to rate the LT-lO, it we were certain, wit hout even hearing it, would appear to be much more sensitive; or that we couldn't expect too much from conversely, if the other tuners used the such an unusually small enclosure- a mere IHFM ratings, they would appear to be 71,4 x 10% x 22%, inches. less sensit ive. Apparently, out of conviction Before going into further discussion of that the IHFM ratings should become its sound qualities, we would like to say a "standard," H. H. Scott is adhering to a few words about the appearance of this rating system which seems to place his speaker system. Without knowing why, we product at some disadvantage. We cannot kuew that the cabinet had been manufac­ help but admire such integrity. tured in some Scandinavian country the One of the things we have been amazed first moment we laid eyes on it. (It was at with this tuner is its ability to pull in manufactured in Sweden.) We still don't stations with a short piece of coa:'{ial cable know why, but we can guess that it is due for an antenna. This occurred when we to the way the wood is finished. The unit connected t he test cable from our FM sig­ we have is mahogany (it is also available nal generator to the antenna terminals. in teak), but it is not a variety we see very With no more than this l8-inch piece of often; it is reddish in color like Philippine coa.."{ial cable we were able to receive any mahogany. Anyhow, it is hand rubbed and station in the New York City area. With the resultant cabinet seems to have a warm the dipole antenna supplied with the kit we glow about it. Very tastefully done. Fig. 9. Th is is the way it looks when it is received a station in Connecticut which is We have just demonstrated the difficulty first opened. Tag at lower right is sup­ about 50 miles away. in using words to describe the quality of an plied with kit to be pasted on after com- object where there are no rules to go by­ Const ruction indeecl there can be no rules in such a sub­ pletion. 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 assembling and pre-aligning the i.f. stages, Each chart has a key number which the sound quality of the system as excep­ printed cir cuit boar ds, using the tuning matches a particular page in the instruc­ tionally clean. By tIllS we mean that there meter, and so on. By and large t hese tion manual, and in addition each compo­ is a high degree of naturalness about the methods have been increasingly successful, llent on the chart has a key number which sound it produces; highly listenable and although still not as precise as the factory indicates the exact assembly step where it non-fatiguing. It reminds us of the Saab procedure. The method devised by H. H . is used. To make the assembly procedure automobile (another Swedish product)­ Scott engineers, although not necessarily even more foolproof, the illustrations re­ not an ounce of fat on it, and with per­ more accurate, is decidedly less critical. lated to each assembly group are in colors formance way beyond its size. This is one of the bonus extras accruing so that the parts are placed visually as well The bass sound of the Nordic I can best from the wide-band detector. as by description. Unlike many instruction be characterized as tight and non-boomy; The procedure itself is really simple. The manuals, this one is extremely easy to read. it does not have the depth and richness a sequence is as follows: the second i.f. can Figu1'e 9 illustrates the appearance of large system such as the Patrician which is tuned for maximum indication on the the LT-IO when the box is first opened. One was discussed last month. Nevertheless, as tuning meter, the bottom slug being tuned of the innovations in this kit is that it can far as it goes, it is smooth and solid. The before the top slug; the limiter can is be constructed in the box. This is a great source of bass is an 8-inch speaker with tuned the same way (see Fig. 7) ; the first convenience for those whose construction patented, multi-layer, cone construction. i.f. can is also tuned the same way; then facilities are limited. Note the small label Apparently the cone consists of several tIle r.f. circuit is t uned for maximum de­ in the lower right corner of Fig. 9. This layers of different fibres, alternately hard flection of the tuning meter; finally the self-adhesive label is to be filled out with and soft, in a sor t of Dagwood sandwich detector can is aligned, again adjusting t he constructor's name upon completion of configuration. Sounds tempting. the bottom slug first. Adjusting the top the kit and attached to the chassis in an The crossover frequency is 7500 cps al­ slug is the most difficult procedure of all, appropriate position. We presume that this though the 5-inch tweeter actually starts and it is at this point that the "piece de is meant to confel' status and recognition operating at 5000 cps. The tweeter is resistance" is un veiled; an ingenious upon the kit-builder. It may at that .. mounted on a rigid, solid, die-cast frame method utilizing a light bulb. The bulb, The under-chassis view of this kit is which makes it an unusually rugged unit. which will later illuminate the tuning indio slightly unusual; it is just too simple for The music power rating of the Nordic I cator, is connected to the speaker terminals an FM tuner. We are used to the "rat's is 20 watts. We used a 10-watt amplifier of an audio amplifier to which the tuner nest" maze of wires common to most FM to drive it and obtained all the sound we has been cOllilected. tuners. In contrast the wiring of the LT-IO could stand-in level, that is. We might Next, the bulb in its holder is then placed seems barely appropriate for a baby rat. add that the sound did not seem "forced" between an i.f. can and the shield over the I n summation, the H. H . Scott model at high levels. tuning capacitor. Now the slug is rotated LT-IO is an excellent FM tuner kit which In sum, then, the Nordic I is ideal for and the resulting brightening and dimming is unusually easy to build. It is well within the audiofan with limited space and a of the bulb noted and compared with the the capabilities of even a beginning kit modest budget. Its sound quality is excel­ patterns illustrated in the manual. Then, builder- providing he follows the simple lent and should provide many hours of en­ all that is necessary is to locate t he slug instructions. B-29 joyable, nOll-fatiguing, listening. B-30 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 Fig . 10. Ercono with the original alignment. We could not Nordic I spea ker hear any difference after the tuner was syste m. aligned using test equipment.

Performance The performance specifications of the LT-IO, as stated by the manufacturer, are quite gooil: especially in light of the ex­ plicit guarantee by the manufacturer that

56 AUDIO • FEBRUARY, 1961 A sensational sight with sensational sound, the new JBL Olympus has been This is' the new JBL S6 Linear Efficiency Sys.' enthusiastica\ly acClaimed at every preview for its unprecedented fiat, accurate tern with a new 15" low 'frequency unit, new dividing network, new high frequency driver, reproduction of the entire audio spectrum. The .olympus has remarkable bass and new horn and acoustical lens. The new response . . . goes all the way down smoothly clean. It reproduces the lowest LE15 is made with a 4 ~' edge·wound copper fundamental in all its rich, original power. And does it in the JBL manner­ ribbon voice coil, long·throw Lans·a·Loy sus· pension, rigid" cast frame designed for mount· with precision articulation, accurate delineation. The new slant-plate acoustical ing from either the front or the rear of th.e lens refracts equally all frequencies which pass through it. Not only does this baffle. This is the only 15" unit on the market heighten realism from any listening point, but permits a new latitude in capable of linear cone excursi

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 as on a stage, heightens his :Ilone-ness, the bunching-up Amusingly, everybody "looks at you" in of two people into the other speaker d ra­ the playhack, reganllE'ss of positions in the AUDIO ETC nUltizes their togetherness. Given the right recording. A helter-skelter crowd of people material, this arrangement adds enormollsly lounging all over a room, standiug, sitting, '(from page 15) to recorded dramlltic impact. Similarly, you fneing this way and thnt, emerge in a dual­ do, in fact, share vel'y little common sound, may recoril two musicians on one mike a chnnncl rec'ording neatly lined up and all whether room li,'eness or the Mo unds going third 011 the other, facing straight forward! Thus you don't have to arrange your amateur recording the 0VIJotiite mi ke, Thq stand on their You may, of course, try the next cate­ to perfopners in lines and ranks. Just take own, withuut reconled livcuess, amI Ih<'y gory, two performers on each mike, but a may indeed ue Vlayed back iu the ausolute lIIlIch more interesting variant of thE' Two­ them where they stand or sit, llIakillg ,,"'e manlier, i.e., at the literal ,'olulne of the Point approach is that which trpats of ollly that they bunch to some extent into origiual so und, for a very litera I sort of groups. When YOll have a l:1rger number of groups (as they usually do anyhow) for reproduction, each voice or, instrument lo­ people to cope with you will be tempted to the "xploring mike, close-up. cated iu its own speaker. try real stereo-i.e., to move your mikes The strallgetit aspeet of this surrE'alistic But you will find, 1 think, that for gen­ back for an o,-er-all "sounrl-curtain" pick­ rea lism tand it's lin eye-opener as to the eral entertailllllent and/or reprodueed im­ up, with everybody located in his rightful relation between recorded sound and live pact the good old exaggerations of ordinary position across the stage. originals) is tll:lt the rlllal-"llllnncl meilium recorded soulHI tierve !Jetter. The princivle Don't do it I Don't even try. For you'll will make proper, staid, rational rE'coTiling of "realistic dititortion" easily wins out very likply fniI. As I say, rea l stereo is out of the za lIiest mike antics you can and you'll play your recordings genl'rally tricky and needs precisely right mike plaee­ imagine. Anything goes. Anything goes, much luuder Ihan the urigiualM. We always ment and right acoustics, seldom of the sort that is, so 10llg as you make no attempt do, in rOUlIl-size rt'cof(lingM. founil in living rooms. whatsoever to be lite·ml. That you cannot In fact, here you have a rather special Iustea d, di\"ide your people into groups, do! No matter how hnrd you try, the two and unexpected dralllatic tool of great lIexi­ Cluster one group around one mike, another sl'eakprs will take your spatial material and bility for your playback sound. You may around the other, all as close as conveni­ r enrrauge it aeconling to their own prin­ vary the relative loudness of your two ently possible, C~ote that as long as a few ciples, You can make only one miRtake : ch annels for ea,'h performance, with aston­ voices-or instruments-are highligilted too-distant miking. As long as YOll will in­ ishingly diffel'ent results! You have two close to the mike, the listening ear will not sist uJlon sOllie part of your total roomful volume controls, uot just one. You can ad­ object to an "off-mike" sounil, at a dis­ of sound heing close to one mike or the just the playbm'k ualance between channels tance, for numerons othcrs. The contrast other, or both, you cannot go wrOllg nt all. o\"er a rolatively huge range, and you never afforcls audible perspective, near and far. You Illay mo"e yonr lIIikl's C]uirkl~' any­ where you wi sh, to fulfill this c-ioscnesR, and 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.) the 1lI0tion will he undl'tp ~tible. It cannot you'll adlllit. Inedtahly, in spite of the closest pos­ be perceh'ed, in the play hack, ns motion; it For instance, I maile one very pleasant sihle mike positions, you will begin to in­ com es out instead as a kinrl of professional clurle an appreciable amollnt of general fade-lip, or fnde-out, 110,-e your mike recording, ,-i" this prin~iple, of a hoy with a low batis ,-oice singing a 'Iuipt bluI's song, room liveness, souud common to both chan­ quickly awny from one voice or instrument to an accompanying guitar. Followiug the n~ls, in this sort of group recording, That and the sound merely fniles cl own unohtru­ Two-Point systeUl, I put one mike right Will be enough. Don 't force the ste r ~ o issue. sively in the playhack. A polished IInrl very next to the fellow's nllHI! h, since he Rang at If you consistently avoid stereo via maxi­ professioual sound it is, though to look at mum group close-ups, you'll likely end with YOllr mikes zooming hither and YOll, you a very low \"01 II III e. The other mike went close to the guitarist's fingl'rs, a COli pIe of an appreciable true stereo effect in spite would not believe it possihle. yards distaut. You could scarcely hear the of you rself, Works that way. , Knowing that anythiug surrealistic you "live" singer nrross the roolll; hut I hud Ana now for surrealiRm. What do you can do will merely add to the "realism" playback effec·ts in mind. One rhannel do if there are three or four groups~ Can't and impact of your recording, you will picked up 95 per cent miee, the othp.r the put two in one mike, The answer I found soon len TIl to follow up and exaggerate same 011 gllit:H; the o,-erlap of sound was is simple. Just jump your mikds around~ your surrealism. During that musie,,1 song­ just barely au,lible. _ from group t.o group, freely in the hand. fest, for instance, T noticed one little five­ On playback, the light bass voice was What? Move the mikes in the middle of year-olcl ecstntir·aIly singing away to him­ amplified hugdy, and tUrJwd ont as a tre­ a recording' Professionals will swoon with self as the others sang, making up his own mendous, big, solid sound-this is an old horror. But that is exactly whnt I did. words and tune. I C]uiekly whooshed one of my two olltstretrheil mikes ov('r to him mike tri~k_ The guitar recording was lit­ For example, one evelling I took down a lot of party singing, The gang started on eral, absolute, lout could be pla~-ed at any hold!ng it a few inches nbo\"e his hend (and volume, from a whisper up to nn ominou,ly a musicnl round-four parts. Four groups. looklllg fixerlly in illlOther direction to ,lis­ huge, hl'a '-yweight beating, almost or('hcs­ What was I to do' I pointed mike No. 1 tract him). The result was delightful anil a tral in impact. 1 was thus a hie to vary the at, group No, 1 when they began the tune, great success in plnyback though the voice combined channels for a whole gamut of nuke No.2 at the second group ns it took was enormously blown up in size. A good different musical effects. up the round in turn. Then when group close-up. Use your Two-Point close-up technique, No, 3 came in, I simply switched the first * * * then, ad lib for a choire of liternl realism mike through the air, at nrm's length, right Yes, there are other, more r easonable or free fantasy. Vary your playback-real­ over to that group, and the same with the (and more difficult) types of dunl-channel ism in one spcaker, falltasy in the other_ second mike for group No.4, Needless to mike techniC]ue for home use, including A tiny \"oice on the right, a m:JInmoth say, both mikes pulled in large amounts of careful, ~aleulflted semi-pro st('reo. I'll monster on the left. Experiment with vari­ background singing and the groups were relegate them to a later moment, including ous musical combinations, ... You can go merely closer to a given mike by, say fif­ an old favorite ree.ording device of mi ne on and on. teE'n or twenty per cent. But the mere effort now enthusiastically revived-true binaurai on my part to get each mike as close as I recording for earphones_ I'll never tire of Three Points and Up could to the center of each group ensured thnt, and I'm now making new converts (as the British sny) that the over-all sound among those who hnve been subjected to it When you begin, inevitahly, to experi­ was alive and not overly off-mike. for recording purposes. ment with more than two sound sonr~es you .A nd what happened with the flying My most spectaeular recording to date will edge into a less extreme hut even more m!kesf I 100k('iI like a windmill, and ench I'll let on, was a tape of an entire Thanks: flexible category-it was here that I dis­ mIke traveled dozens of yards throu<7h space giving day dinner for 35 people, straight covered dual-channel surrealishm. during the recording. But on the piayback throllg? from c~cktails to dishwashing, If you record two guitars and a singer not a singer moved an inch. The whol~ done bmaurally VIa two mikes draped over you'll ha\"e to dh'ide your mnterial two to g~ng seemed to be neatly lined up on a the back of a corner chaise lounge. I just one; but your T~,- o-Point technique is only WIde stage, to left and right. In fact, to let 'er run. Afterwards, I sat myself in the moderatp.ly modIfied. Keep the maximum my amazement, this was a real stereo re­ same chaise lounge at the same spot and separation. On the mike that picks up two corrling- surrealistica lly achieved. heard the entire party all over agnin in my Bou~ds, two performers, you')) move back The principle is simple and interesting phones, conversation by conversation. Fas­ a bIt, to take in both, Less literal in the well worth taking to heart. ' cinating. pirkup, with somewhat more room-sound Th?ugh the recording mikes may move But b,efore your Mr, Average Home Tape (liveness), but e\"en so, you can follow the errat~eall:>: and even wildly, pointing any User tnes that (and he'll need a pair of Two-Point Principle and you'll get a new old directIon, front, rear, up, down side to phones for every listener), by all means range of dramatic effects. side, the playback sound reflects' almost urge him to, try just plain, ordinary, sim­ Record a three-way dramatic sequence n~n e of. this, Tnstenrl, the illl:1ges move ple Two-Pomt Close-up home re~oriling. for i.nstance, with two eharacters (clo " e~ slIghtly if at all, and most of the motion It's marvelous fun, and the "surrealisticer" up) ill one channel one in the other. The seems to be quite formal, from side to side, the better. n:

AUDIO • FEBRUARY, 1961 Does the music from your high fidelity system sound clouded reliably cleans records is the 'Dust Bug', marketed by ESL." by noise? Faithful reproduction requires that records be Try the Dust Bug test yourself. Ask your dealer to demon­ scrupulously clean. Even factory-fresh discs contarn groove strate an ESL Dust Bug on a new, never-before-played record. dirt, as you can easily prove. The accumulation is amazing. After an exhaustive six-year test of record cleaning prod­ The automatic, electrostatic record cleaner is only $5.75 ucts, C. Victor Campos reports in the authoritative American (changer model $4.75). Greatly increase the life of your en­ Record Guide: "The only product that I have found which tire record library for less than the cost of a single disc!

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acquaintances for new music to try, and Handel: Acis and Galatea (abridged), RENAISSANCE AND BAROQUE occasionally-an unheard-of faux-pas-they Soloists, Oberlin Choir, Camerata Aca­ allow a girl to sing with them. Des Salzburger Mozarteums, -" Spanish Music of the Renaissance. New But that is only because iu the old days demica York Pro Musica, Greenberg. they used countertenors, and counterteno~s Paumgartne r. Decca DL 9409 today are only beginning to be grown agam Epic BC 1095 stereo from seed. Not yet enough of the gentlemen (mono: LC 3724) The Pro Musica, under Noah Greenberg, sopranos and altos to go 'rounel. has developed. into a remarkably efficient A glee is just a sweet bit of male harmo­ This is a curious mixture in the per­ unit of production for the reconstruction of nizing the ancestor of barber shop. A round formance, and most revealing, too. T.he sing: "old" music into practical modern perfOl'm­ is a ;ound, a canon which goes 'round an.d ers are student s of Oberlin College III Ohio, ance. It has built up its own music library, ' round, everybody singing the same mUSlC spending their entire junior year in Salz­ bought' a fl\scinating brace ~f old ins.tru­ but at different times. A catch has double­ burg; the orchestra Is the local academic ments- bells virginals, harpsIChords, vlOls, entendreB, blanks here and there so that un­ outfit attached to the Salzburg Mozarteum. portative , or~ans-has an office and a mailing mentionable meanings are produced via in­ The conductor, Herr Paumgartner, is the list, a mUSicologist to dig up the music and teraction between voices. Good clean fun, Salzburg factotum, a first-rate conductor ~r prepare It for mass-production. . . . and in ,thpse ,days you c

AUDIO · • FEBRUARY, 1961 VIIv----fFJ0 AUDID FIDElIT'l records

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AUDIO • FEBRUARY, 1961 61 me in LP form back aronnd 1954. A number (8pecificfllly tbe oldest is 62, tbe younl(est of Vox Bets have been comhined here to 51). All of tbis sbows up in this new album, cover the whole set of concerti. and hence which is dollt'(i up ill II pleasing mHIIIH'r with tbe pair of orl(llnists. a ion/.: essay on tbe Budnpe"t eXl'erpt.. d from These are lh'ply. straigh tforward play­ the Xew Yorker. by Joseph Wecl!sherl(. Ings, with an intelligent rpcordell balance Tbe Budapest Beetho\'en sbows botb the between the organ and on·hestra. the organ adnlntnges and dislId\'antagl's of long ex­ l>ig enough hu t not, as in some r,'cordln):'s, perien\'e on the highest plane. Tbe inter­ so close as to dpstl'oy the sense of ensemble. pretation", per se, CIW scarc\-Iy be hent by The orchestrn. though In a bll( SP"('P. is a ny olher living, quartet for "beer econumy leaner nnd lh'elier than thnt in the Colum­ of 1"'e"entaUon. for the deptb of 1II1ut simply in a softening of the reissue nnd was gratified to find. in Ild(li­ the sbarp ou tline of tone. in weak notes tion to the adjustment to RIAA (en"ily bere and there (utterly unimportant. bnt noticpahlp). n smontJwr ROund nnd, 1110st there nevertbeless), in a sligbtly tbin, metal­ notably. much improved surfaces, Our present lic toue of ensemule as comjJal'ed to the uue­ semi-noiseless plastic is perhaps tbe greatest tuon" richnes" of some of the more self­ improvement ill recorueu eO:ecti\'elle8~ o\'er couscious younger quartets, the last fi ve or s ix yeal's, stereo or no stereo, Culumhia hilS nicely solved the problem of quartet stereo--wbether to buncb tbe play­ ers in the m.d<.lle for a semi-mono effect or QUARTETS AND BALLETS to spread them out, witb a risk of the in­ Gould: St. ing Qua. tet, Opus 1. The Sym­ admlssaule "straigh t line" eU'ect, all the vluyers lined up in a roW. Here, a miid but phonia Quartet. dellnite bi):, Ih'eness b elps to place tbe group Columbia MS 6178 stereo between the two "peakers and a bit back; yet tbere is enoug-h separation so toot tbe If the yonng composer of this qnartet first fiddle is dellrly more to the left than were not snch a valnahle piece of plnnl"tic tlte vlulu aud the same wltb second fiddle 1}l'Opert~· . Culnmhln ml/!ht not he promoting and cello, this partIcular recording, But tbe music is intprfl'~til1J! n:-t nil f'x :'l11plf' of thp work of 'iou'll find that a very delicate adjust­ an unusual musical mimI in tbis day and age. ment of thl' halance COlltrol is required to It Is hoth dl1l'u"e lind nniye. yet complex get tbe qual·tet squarely in between your nnd ad\'Ancl'd: its inconcJu"iYe st~' 1 1' stems two tlpenkt'l'::it UI:H:mmiug us ulwuy::; that you most pr()mlnpntl~· from early Sphopuherg, bu\'e lhem fa r enuu;,;h apart to pro\'lde n but s110w" the inl1upure of a do>.en othprs, respel'taille stereo ell'ect. (More tltun six from Bach ancl late-Rel'thoven to 81r>ll1SS, feet ill most Ih'!ng rooms.) If you ba Ye on&­ Franck. and almost An,body else of a serious pl~c~-cHbinet Slereo you migbt us well for­ na ture you Clln mpn tlon ! get uuout ull this; your music Is mostly In oth pr WOTlI., thl" Is n hnlf-hnkPll work, wuno, und tbat is tbat. but of great earnestness and Intensity. striv­ ing for the highest sort of expression In a g reat tradition and hitting it off momentarily in many quite startlingly powerful passages. Ballet Music from the Opera. Paris Con­ Like many an early work f,'om a strong musi- cal minrl. it throws the book. yet mnnllges servatory Orch., Fistoulari. to be verbose and diffuse too, Fugues. contra­ , RCA Victor LSC 2400 stereo puntal structuring. largl'-Acnle sonata fOI'm, pregnant motives 1\ la Beethoven (lnst quar­ Maestro Fistoularl a ppears to be a n im­ tets). a motto of foul' notes out of whicb pressive conductor for ballet-type music of everything in sight and sound is deriverl-­ t lds pleasuntly old fashioned sort, jndglng chromnticisms. long passages of ominous frum this und the London-Richmond WOIlO tr~mulanrlos. anrl. of course. the obviously releases I've been listening to. Thi" Is a prl'gnant fact that this is a quartet. not a grand stHeo recording, a clean, peppy but symphony: in ten seconds you will know that well-llIHnnered performance-rather surpris­ the quartet fo.'m is hel'e chosen as the hil(hest in/.:I.v nPllt Hnd In tune for a l.' rpnch play­ form of musical expression. It's that kind of iug--which does the best tbat aan be done THENEW'Ro-SOtft muxic. fur th~ mush- without pushing it too hurd TI.erc are passages that sonnd mprely inept into sumething it isn't. lmpeccahle tempo, 1/990" 4-TRACK STEREO to m e and t here is n vast sense of drnmatic phrasing, lovely balances e \·erywhere. iu­ anticlimax. t hanks to too-hard working of grHtiatlng sount! of smoothly played violins, TAPE RECORDER lofty matprinl. Bnt ns T say, thprp are "",1- Nice hi fl. too. with tlte familiar blls"-drum­ denly striking passages too--often those and-c.nnbal tillllnps most effectively recor(led. IS YOUR BEST BUY! which arp furtlwst oul in stylistic incon­ 'I'here's I.'rench and Italian dance music gruity, snch as thl' Brnhm"-Iike second from "\YiIliuUl 'Tell H "Kbovuntchina" theme. The whnle work is a slncpre a nd "Sumson and Delilah," 'aud "Aida." ' Only ROBERTS "990" combines hl'nrtpning change f rom too mnch Rnre hnt these features: pmpty tp,'hnlnnl' liS rlispln,pcl In II tllol1Isl'. In all honPHt,? If ~lozart'" PIIrly Richmond BA 42003 mono compositionR wprp ImpPC'cahlfl, FIn W;)N his power amplifier outputs· dual monitor Tchaikowsky: Sleeping Beauty (complete). early tl'll ining in the thpn pxrltlHlvplv "pon­ Paris Conservatory Orch., Fistoulari. speakers· portable and easily custom temporllry" ml1"lc tl.llt "'flS a ll hp I'vp~ hpllrd, installed. Compo.inl( a 11(1 pprfnrmlnl( wprp line, A. a Richmond BA 42001 mono piflnlst. todny. (innlc!'s performing refipcts Ash for a Free Demonstration at your Near­ our time•• from Bach to Webern. Can his Here is more Fistoulnri ballet music, and est Franchised Roberts Dealer: own music do otherwise? two 1""eIiPl' luw-prit-ed specials I cau't con­ Send for Roberts grea t NEW Stereo Informa­ ceh·p of. The re(,ol(ltn~s, in 1110no. nre reully tion Kit. 34 tape applications covered, Enclose sl'lpndld an,l perhaps only the luck of a 25¢ for handling and postage, stereo version put" tbem into tbl' inexpen­ Beethoven: The Middle Quartets (Opus si\'e (·ategory. I"avoraule economics for tbe Roberts Electronics, Inc , A2A 59, Nos. 1-3; Op. 74; Op. 95). Budapest COllHlllUer! 829 N. Highland Ave" los Angeles 38 Quartet. The complete Tchaikowsky hallpts can be Please send me: . Columbia M4S 616 stereo bell\'y !!,lIing in the long pull--they n ren't D Roberts Stereo Tape Information Kit con­ (mono: M4L 254) shllrt aUli. though key t11Pllles do rpturn taining 39 stereo and monaural applications. ) of len. tllp shepr piling up of so many gbort­ enclose 25~ (cash, stamps) for postage and handling, The Budapest Qual'tet Is rpcorcling the ish (I:lllce pieces. plu" those eternal fancy D The name of my nearest dealer, Beethoven Qnnrtets for thl' thit'd time Billre mnsi('111 perorllti"n" (for the dllncers. of D I want a free, no-obligation demonstra tion, joining Cnlnmhia In lhp 7R-rpm dll,s (nnd c"urse-to he plllypd against storm" of clap­ Name ______hefo re that tlw,\' did splendid work for RCA plnlr untl hrll\'''s) can run you quickl, into Address ______Victor). The gl'OllP is now thl' "Bil(l(Pst slltlety. But ,,'orst of all. with TchaillOwsky, Nam(''' in the chamher music hURinp~~ nnd, I_ 11Il~' pprforlllHnl'l' that triPR to push the City State r by dint of sheer pas"ing time, is now clearly wl'lI-knnwn 'l'l'huikowsky wel'ping ancl waU­ ------~ a middle-aged quartet, if not an elderly one. lung too bard. It never should outwardly 62 AUDIO • FEBRUARY, 1961 Save up to 66% on G Hi-Fi 12-inch 'lP CLASSICS 4.98 List BONUS RECORD Plus FREE WITH EACH ORDER

5·V·l0540. MENDElSSOHN, 5·V·11570. BEETHOVEN Son· 5·V·9632. CHOPIN Noc­ Concerto in A Flat [or Two a t as, "Pathetigue," turnes. Novaes , well­ Pianos and Orc hestra. " Moonlight, " " Wald­ known Chopin interpretor, 1 .:::2:::===::'~1.LlJ..l'.J Frugoni and TaddeI. stein;" .. Appasionatta." p lays many lovely noc· .. 5·V·9740. PALESTRINA, Le Frugoni, pianIst. turnes. 2 disks. Vergini; Stabat M ater a nd 5·V·8870. BACH, Concertos S·V·l0490. CHOPIN, 4 im- the Super Flumina Baby· in C and D [or 3 harpsi· promptus and 4 Ballades lonis by Lecco Academy chords; Concerto in A [or [or Piano. Frugoni brings 5·V·l0720. VIVALDI. 5 COn­ Choir. 4 harpsichords. Reinhardt certi for Oboe and Orches­ conducts. ou t a ll the brilliance of S·V·l0020. PALESTR INA, Chopin. tra. Caroldi is the virtu­ Missa Papae M arcelli; S·V·a5S0. MOZART Concerto oso oboist. Santi leads the Missa A ssumpta Est in C [or F lute and Harp; 5·V·8040. BRUCKNER Sym· Accademici di Milano. Maria. Adagio, K. 617 and An· phony No. 9 in D. Pro dante, K .315 . Fine record­ Musica Sym. Horenstein 5·V·l0750. BRUCKNER, S~m- S·V·l 0170. SCHUMANN. Sym· ing by Pro Musica Orches­ conducts. phonic Etudes and Fantas· tra. b~~:fY ~~dJc~n f~ Ihi.; iestucke. 01'. 12 recorded 5·V·l0260. MOZART, "Coro­ original. by Novaes, pianist. 5·V·8l40. WEBER Piano nation" Mass a nd V esper~ Concertos Nos. 1 a nd 2. ae. Pro Musica Symphony. 5.y·l0760. BERG. Concerto 5·V·11300. HANDEl OVER· Wuehrer, pianist with the for Violin a nd Orchestra; TURES. Alexander's Feast; Pro Musica Orchestra. 5·V·11452. HAYDN, The STRAVINSKY Concerto in D Ariadne; Ezio; Jephtha; Creation (Oratorio). 2- for Violin. 5·V·9440. GLUCK , PERGOL· disk- set in superlative re­ Pastor Fido; Rodelinda; ESI, BOCCHERINI. Concertos 5·V·l0790. BOCCHERINI Con­ Terpsichore; Theseo. Rein­ cording by Horenstein a nd certo in B Flat for Cello [or Flute and' Orchestra the Weiner Volksoper. hardt conducts. recorded by Pro Musica and Orchestra; HAYDN 5·V·11200. BRUCKNER Sym­ Sym. 5·V·11480. VIVALDI, The Concerto in D for Cello; phony No. 4 in E F lat, Four Seasons. 'Most fam­ VIVALD I Concerto for Cello 5·V·a170. COMPLETE CHOPIN a nd Orchestra. . 'Roma ntic. I I Klemperer WALTZES. Novaes in a shin­ ous of concerti for violin directs the Vienna Sym. ing disk o[ perennial fav­ featuring Accademici, 5·V·l0940. CHOPIN Pre­ orites for Jllusic lovers. ludes (24) 01'. 28 and Son­ S:V·l0930. CHOPIN Etudes 5·V·11490. BARTOK Piano a ta No.2 played by No­ Op. 10 and Op. 25. No­ 5-V·l0740. VIVALOI, 4 Bas· Concertos No. 2 a nd No. vaes. vaes, brill ian t pianist, soon Concerti. Bianchi, 3. Sandor, famous pianist. 5·V·11642. HANDEL. Israel 5·V·11160. SCHUMANN . Car· oboe. Santi conducts this unusual program. 5·V·10730. BACH. Concerto in Egypt. Recorded here naval; Scenes from Child· [or F lute, Violin and Harp. by the Dessoff Chorus, hood a nd P apillons. The 5·V·l0460. SCHONBERG , sichord; Concerto No. 3 m Sym. of the Air. 2 disks. muster of piano composi­ Verklarte Nacht. Horen­ D for Harpsichord. Mess, tIOn interpreted by No· stein conducts this great flute. Stuttgard P ro Musi­ 5·V·l0200. SCHUBERT. Sym· vaes. work. phony No. 9 in C. "The ca, R einhardt condu~ting. Great." Perlea conducts. ~M~O'""Z=-A"'R"'T=-G~!~~~_ I~N: 5·V·12. MOZART Strin g 5·V·6. SCHUBERT Quintets Quartets. Nos. 1 thru 10 in A Major, "The Trout," 5·V·7. BACH M ass in B plus Adagio and Fugue. C Major. Qua rtets in D Min or, with Libretto. Barchet Quartet. 3 disks. Minor, #14, " Death and Bach - Festival arch. 3· 5·V·8. BEETHOVEN Music the Maiden," B F lat Maj­ disk set . for Cello and Piano. Com· or. 3 d isks. 5·V·15. BACH, Suites for plete 5 sonatas plus 3 sets 5·V·23. HANDEl, Complete Unaccompanied Cello o[ variations. 3 disks. Organ Concertos, Vol. I , (complete). Cellist Gas­ 5-V·202. BACH, St. John 1·9. Walter Kra [t organ­ par Cassado. 3 disks. Passion. G rossman con­ ist with Pro Musica, Rein­ S·V·14. MOZART, String 5·V·200. BACH St. Matthew ducts Vienna Sym. 3 d isks. hardt conducting. 3 disks. Quartets, Vol. III (com­ Passion. Complete with 5·V·24. HANOEl, Organ libretto! Vienna Chamber 5·V·401. CHOP IN, Piano plete). Performed by the Concertos. Vol. II. Con­ Barchet Quartet. 3 disks. O rchestra. 3-disk set. Music, Guiomar Novaes. certos 10-16 . Organists 5·V·25. BACH , Brandenburg Etudes, 01'. 10 a nd 25, Walter Kra[t a nd Eva 5·V·ll5. MAHLER, Sym· Concertos (complete), Vio­ complete Waltzes; Pre· Hoelderlin with Pro Mu· phony No.2, "Resurrec. lin Concertos I, 2; Con· ludes, 01'. 28 complete. sica Orchestra. 3 disks. tion" a nd Das Lied Von certo, D Minor for 2 Vio· Sonata No. 2 in B F lat. 5·V·13. MOZART, String Del' Erde. Vienna Sym. 3 lins . 3 disks. 3·disk set. d isks. Quartets, Vol. II. Barchet Tremendous savi ngs on 3-record albums of 5·V·ll0. MOZART, Piano 5·V·3. MOZART 6·String Quartet performs quartets Works of th e "Masters!" Those hard-lo-get S·V·20. VIVALDI, L'Estro Concertos (complete) Nos. Quintets. B F lat M ajor. C E fl at Major, B fl a t Maj­ landmarks of classical co mposition in spar­ Armonico, Opus 3. Twelve 22 through 27. P ro Mu­ M inor, C Major, G Min­ or, D Minor, K . 172. 173, kling high fidelity! All latest releases. Beauti­ concerti for string orches­ sica Orchestra of Vienna. or, D Major. E Flat Maj­ 174; G Major K. 387. D fully boxed with li bretto and complete his­ tra. Pro Musica. 3 disks. 3 disks. or. Barchet Quartet. Quin­ Minor K. 421, E fl at Maj­ tori cal notes. 5·V·ll6. MAHLER, Sym­ 5·V·20l. BACH , Christmas tets. Nos. 2 thru 7, in· or K . 428, B fl at Maj"r. phonies Nos. I, D Major aratoria. Vienna Sym. c1usive. 3 disks. ORDER ALL YOU WANT ! NO OBLIGA­ K. 458. 3 disks. TION TO BUY MORE DISCS LATER. a nd 9, D Minor. Also Kin­ Kammerchor conducts. 3 SATISFACTION GUARANTEED dertotenlieder. 3-disk set. disks. r--- ORDER NOW-USE THIS HANDY COUPON----..,. I Radio Shack Corp., Dept. 61812 730 Commonwealth Ave., Boston 17, Mass. I I Please send me the following selections. I understano I will receive reg . $4.98 FREE record, I I "Glockenspiels, Traps and Pl enty of Pipes" with each order I place. • I ~~I~~~ef~~~o; it he ~~~:t~ 3-record albums at $5.99 set 2 records for $4.98 I I tance. Send Check or list number for each list PAIRS of numbers I Co," RADIO SHACK I ~~n;rs ~rt~rd S;~7 ' f:~ I I postage & handling I Where America' s Music Lovers Shop by Mail I ~~! tO!fM~Si~~s.sip pi; 50c My name (print) I 730 Commonwealth Ave., Boston, Mass. I ~:~EaJi~a~ha~~~: c;~~~~ Address : L~~~Catalog s______with each City Zon& __ State___ _ ~

AUDIO • FEBRUARY, 196) 63 be pushed in allY of his scores, symphonic or no. H e tells his own story best in terms of careful accurate playing as per the writ­ ten score.' But in ballet music, the over-ripe approach, the semi-hysterical, can be utter­ ly c eadly. Fistoulari is marvelous here. Everything wonderfully neat and accurate, 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 listening, this mah, with both the British_ and the French orchestras, has the right; tIte 'inusical way and no doubt about It for my taste. I'd put these at the very top of all recordings of th 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. Kapp KC 9046-5 stereo I played this disc a few days after I'd made a pleasing visit to the City Center it­ self (dilferent music) and I was astonished . to find how familiar was the sound of these ballet scores. The Ci.ty Center prodnctions have a very positive, though perhaps in­ definable, aura and quality 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 recordings, 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 roles are changed and the brass IS ex­ cellent 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, work­ Also manlike and musical ballet conductor even .if avai lab le he is not always able to make his somewhat with StereoRamic frenetic players sound like the Philadelphia Tone-arm and Orchestra. .A. good diSC, this. Cartridge or The cover titles are those of the ballets ; Professional the music is the seldom-heard fragmentary Tone-arm Tchaikowsky Thi,-d Pinno Ooncer:to, selec­ just and Cartridge tions from "Raymonda" of Glazounov, and "Russian and Ludmilla" of Glinka, the whole disc Russian.

this! ODDITIES superb sound! • • • trouble-free listening enjoyment! Rita Ford Music Boxes in Hi Fi. Dot DLP 3236 • .. years ahead design features! . . . speed preference, This collection makes a nice addition to those I've had previously from the Bornand 331/3 or 45 rpm, with just the fl ick of a switch! company and others. The variety is quite large and a few of these machines produce Weathers leadership and pioneering in the com ponent field has produced rema:-kably involved 'and interesting musical what is undoubtedly the world 's finest ,2,speed turntabl e! Compare it with all arra'ngemen ts of overtiit'es a nd the like. No ot her turnt ables .. . t hen you' ll apprec iate' t he 100% perfect performance wheezing and out-of-tune sound here--Miss of this remarkable inst rument ! A minimum of parts, working with' maximum Ford keeps 'em in apPle pie order. Featured are the orchestrion, a beer garden (yep). efficiency, operate trouble·free year after yea r. All parts are matched and an ariosa, a manopan, assorted Swiss clock balanced for t he ultimate in sound reproduct ion! Two-speed bu ilt·in con­ boxes and an 18th century organ from Eng­ venience lets you listen t o your favorite al bums by merely flicking the switch. land. Tone arm tracks with a force of 1 gram, causes no record wear for a lifetime! Wa lnut or ebony wood base wit h gold mountings has the smart styling that A ProgrC;lm of Russian Song. Jaroff f its in with any decor. Pl ayer comes completely assembled and ready to plug Women's Chorus, Serge Jaroff. into any existing aud io syst em! . Decca DL 710019 stereo SPECIFICATIONS The diminutive conductor of the Don Cos­ Write for f ree folder a',;'d no me Power Req uiremen ts ...... 70 to 125 volts sacks (he's always called t hat) is now al­ of your nearest dealer t ~: 60 cyc les, 10 wa lts most too plump for his cossack uniform after Rumbl e ...... - 70 db (NA RTS measur ement), some forty-odd years of plumping for Russian WEATHERS INDUSTRIES with maxim um energy at 10 cycles music outside of Russia, but he still h as Wow ...... 0.1 5% A Division of Advance In dustries, Inc. the same way with his voices--even these Flu tter ...... 0.10% ladies, a new angle to his characteristic work. Speed Acc uracy ...... Within ± '0.1 % of 66 E. Glo.ucEl.$er- Pike, nominal speed They're good, very good. . Hum Radia tion ...... Neg li gi ble What I keep wondering, now more than Barrington, ·N. J. Tu rnta ble only ...... _ ...... $14.50 e,-er, is how do the Cossacks (and these D!lW Avai labl e in single speed 33 1/3 _... _.. . ~59 . 95 ladies) keep perpetuating themselves from non-Soviet sou rces ? Are they really Russian? They sound it. Do they never get any older? "Weathe r s Technica l Mag i c is Sound" They don't seem to. How recent is their

64 AUDIO • FEBRUARY, 1961 latest contact with the Mother-land? Is the tradition (including the singing style) kept alive strictly in exile, without refertilization Latest Issue of 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 TUNG-SOL TIPS heard numerous recent Russian folI' record­ ings (have the Cossacks 1) will note the new harder, more dynamic styles, the higher ten­ tells you what you should '/lnow about sion. 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 MULTIVIBRATOR CIRCUITS Jaroff singers of both sexes are unfailingly musical and boast tremendously interesting and varied vocal prowess. Good stulf.

AUDIOCLINIC

(f1'om page 4)

9-spea7cer systems. I have set the level con­ trols according to the method described by the spea7cer manufacturer-by 'ear. The re­ sults are satisfactory to me. However, after awhile, it seems that maybe a little stronger treble would sound better. Therefore, I in­ crease the gain on the treble horn. Then later, I may find that by mising the level of the midrange spea7cer I i1n prove 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 if it did not please my ear, how­ ERE is a typical multivibrll;tor eirc.uit. ~t's just one of several ever. James J. Allain, Jr., Par Allen,' Hwhich perform many baSIC functlOns m computers and elec­ Louisiana. tronic counters and which find wide use as waveform genera­ tors. For the serviceman planning to expand his business to A. Since the actual balance among th,' .industrial equipment servicing, a thorough knowledge of these three speakers in a 3-way system depends devices is a "must". upon the room in which the equipment is To give you this fundamental grounding in multi vibrators, housed (as you suggested), it is impos­ Tung-Sol has devoted the latest issue of its monthly series, sible for the manufacturer to give you Tung-Sol Tips, to a vigorous, down-to-earth treatment of any additional instructions other than those these important circuits. he provides with his speakers. If you have In issue # 13, you'll find a comprehensive, fast-reading anal­ an audio oscillator and a calibrated micro­ ysis of all the multivibrator circuits which you can expect phone, more accurate control settings can to find in your industrial work. These include: the bistable be found. multi, the cathode coupled binary, monostable, astable and Of course, the calibrated microphone high sp,eed J,nultivibrators. must be placed in the position which the The operation and application of each is carefully defined. listener would use' or the resulting readings Many circuit diagrams are included to rouna out your will be faulty. The use of a calibrated understanding. microphone may not be f easible for you, There's more! The author has also included a special sec­ but your ear can be used as a good sub­ tion that gives you maintenance and servicing clues that you stitute. can put to practical use immediately. By using the audio oscillator to sweep Don't miss out on this really important issue of Tung-Sol the audio range you may well hear whether Tips. It's yours merely for the asking. Just drop into your the midrange is louder than the woofer, Tung-Sol distri~,utor. Or write direct.ly. Tung-Sol Electric etc. The best way to accomplish .this result Inc., ,Newark 4, N. J. is to sweep from a point somewhat below the crossover point to one which is some­ what above this point. An octave on each side of the crossover point should be suffi­ cient. This technique can be used for both the midrange and tweeter crossover points. This procedure should be followed with ®TUNG-SOr the observer in the position most usually SALES OFFICES: ATLANTA, GA.; COLUMBUS, OHIO; CULVER CITY, CALIF.; DALLAS, TEXASj DENVER, occupied by the listener or listeners to the COLO.j DETROIT, MICH.; IRVINGTON, N. J.j MELROSE PARK, ILL.; NEWARK, N. J.; PHILADELPHIA, PA.j equipment. JE SEATTLE, WASH. CANADA, TORONTO, ONT.

AUDIO • FEBRUARY, 1961 65 fPijPUlAR ' Continental Encores/Waltz Encores-Mantovani (Twin­ . Pak). london/lCK, LPK-70024 Adventures in Paradise­ MORE Alfred Apaka, RoY 'Snieck, Terortua & His Tahitians, The Islanders. ABC Par-amount/ ATC-816 HAROLD LAWRENCE'" Tonight ... Town Hall Concert -Roger·Williams (Twirl' Pakl. KaoD / KT-45009 The Roaring 20'5- l Grand Award/GASD-229 Portrait of a Rehearsal Ten Greatest Pop 'Piano Concertos / Renowned Pop Concertos- George Greeley: HE CONDUC'l'OR, David Randolph, would prepared, but the fact remained that they Orchestra (Twin-Pak) . . have been justified in experiencing a had not yet been assembled. This was not .Warner Srothers/ PST,2401 Tdegree of apprehension on the morning due to an oversight. The budget of thiB CLASSICAL , December 10, 1960. The Masterwork Chorus non-profit choral organization was already (Morristown, New Jersey), which he had strained by the expenses of a New York Stravinsky: The Fire Bird (Complete Saflet)/ Song of co-founded in 1955, was scheduled to mnke conrert- rental of the hall; printing of the 'Nightingale, Pulc ine lla its Carnegie Hall deuut that evening under tickets, programs, and miscellaneous litera­ Suit~Ernest Ans ermet, . his direction in Bal'h's "Christmas Ora­ ture j payment of nshers and stagehands; l'Orc.hestre de la Suisse MORE torio." A three-hour session had been called and costs of transporting and acco=o· , Romande (Twi n-Pak). london/ lCK, lPK-80042 for 9: 30 a.m. at Carnegie Hall for the dating in New York the out-of-state choral first and only full-scale rehearsal with all singers. Finances simply ruled out more OPERA.' the musical forces involved in the per­ than one "dress" rehearsal. Ponchielli: la Gioconda formance. It was imperative that Mr. Some two hundred and seventy per­ (Complete)-Del Monaco, Randolph operate with unusual speed and formers, therefore, were gathering together Cerquetti (2 reefs). efficiency. The allotted rehearsal time did for the first time. Critical acljustments lOQdon/lOR-90004 not permit a run-through of the complete would have to be made to each other and leoncavallo: Pagliacci oratorio which, counting pauses, is itself to the aeoustical properties of the hall. (Complete)-Del Monaco, more thau three hours loug. To cover the The conductor could only guess at the po­ Tucci. lon~on/lOH-90021 gronnd, the conductor planned to omit cer­ tential so urces of trouble: ensemble prob­ tain repeats and to move ahead to the lems would be the easiest to spot and ne:A1; movement whenever things appeared correct; more tricky were the factors of under control. balance and dynamics upon which the In previous rehearsals, Mr. Randolph hall's sonic ch aracter would have so great MORE had worked with the chorns for several an effect. As the stage began to fill up months, imprinting on the minds of its before him, Mr. Randolph must have felt members detailed instructions regarding like a space scientist wat~ hing a missile tempo, diction, phrasing,- accents, and tone on its launC'hing pad at firing time. quality j and, during the week before the Busy counting the noses of arriving per­ DANCE MUSIC SOUND SENSATIONS Perfe~t for D~ncing / Dancing concert, he had held sertional rehellJ'Rals formers, the conductor found that his own with Ros-Edmundo Ros and Spectacular Harps-Robert with the orchestra, soloists, and chorus. nose had become the object of an early­ His Orchestra (Twin-Pakl. Maxwell. MGM/STC-3836 Now the component parts were meticulously bird photographer, who had forused an London/ LCK, LPK-70038 The Sound of Top Brass, Vol exposure meter on it to obtain a light read· '1 WanUo Be Happy Cha 2-Peter London Orchestra. * 26 W. 9th St., New York 11, N . Y. ing. Other amateur photographers had also Cha's-Enoch Light. Medallion/MST-47008 Grand Award / GA~D-222

A Journey Into Stereo. MORE london/lPM-70000

Pyramid/ NO Sun in Ven ice­ Modern Jazz Quartet (Twin­ Pak). Atiantic / AlP-l,~04 and les McCann Plays the Truth/ • Les McCann Plays the Shouj . (Twin-Pak). World Pacific/ WPTC-1016 MORE MUSIC IS ON 4-TRACK

STEREO TAPE (Photo by Harold Lawrence ) For Free Catalog, write: 1024 Kifer Road, Sun- nyvale, California - UNITED STEREO TAPES Yt'T Fig. 1. David Randolph conducting the "Christmas Oratorio."

66 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 art II of the "Christmas Oratorio," the Pas­ toral Symphony. The battery of lenses aimed at the podium might have rattled other conduc­ tors, but Mr. Randolph was beyond dis­ traction: 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 or­ chestral players were accommodated snugly on the apron of the stage. The clock in the wings read 9: 30. Mr. Randolph in­ spected his musical forces. Noticing an un­ evenness in the ranks of sopranos and altos, he called out, "Will the pregnant women please sit near the doorf" 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 that the podium can be a deceptive listening point from which to evaluate balance. dynamics, and even ensemble in an un­ familiar auditorium. And this was Mr. Randolph's first conducting experience in Carnegie Hall. 5MICROPHONES? GUESS AGAIN! The opening of the "Christmas Ora­ torio," J auchzet, fj'ohloc1cet! with its joy­ In their sleek modern styling, ful punctuation of trumpets and timpani, There's just one ... but that got the rehearsal off to a vigorous start. one has a big plus . . . the in their laboratory stand~rd At the conclusion of the movement, the years-ahead concept of mod­ of performance, University's conductor asked the opinion of the moni­ ular flexibility, an exclusive modular microphones are tors. "Diction, David. We can't hear a feature of University's new without peer. They achieve a word back here, it's all a wash of sound." Mr. Randolph replied, "You realize, of professional line of omni­ clean and exceptionally wide­ course, Shirley, that the chorus is not on directional and cardioid range response - from as low risers. Nevertheless, we'll try it ngain. (To broadcast microphones. Each as 30 cps to as high as 20,000 the chorus) You all . heard that. While modular microphone is cps. They transmit both voice we're on the subject, I should like to add that there's not a rolled 'R' in the bunch. uniquely designed for use and music with clarity and And smile, darn you, this is a happy with any of several inter­ faithfulness that serve as a work!" Articulation and spirit improved changeable adapters ... with tribute to the initial engi­ noticeably in the second attempt, hut the and without switches, for neering concept and the ensemble broke down in the sixteenth-note painstaking care and custom passages. The comlue-tor offered a practical cables with and without can­ solution: "Stay with me, don't go by what non plugs, for screw-on or construction lavished upon your neighbors are doing." slide-on stands. Thus you buy them at every stage of manu­ As the last notes of the choral "Wie soli only the features you actually facture. For full information ich dich empfangen" melted into the quiet need-and need neve?' compro­ about this truly outstanding hall, Mrs. May, unmoved by the ' perform­ new line of professional ance, uttered the startling suggestion, mise on quality just to meet a UNIVERSITY microphones, write Desk R-2, "Shoot the bass!" The bass line, it seems, price. That's tTue modular MODULAR flexibility, and you get it MICROPHONES University Loudspeakers, had upset the musical balance by emerging .•. MATCHLESS IN above the other voices. In another choral, only from University. PERFORMANCE Inc., White Plains, N. Y. Mr. Randolph checked a bad case of sag­ ging pitch with the admonishment, "Think high." 1Il The first and only purely orchestral movement in the work, the Pastoral Sym­ ~~ (Continued on page 78) A Division of lIna:-Temeo Electronics. Inc.

AUDIO • FEBRUARY, 1961 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 and 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'ing fo r Capitol engineers, and the plpe is passed ba ck and forth Indian fashion by brass and reed sections on Stel'eoso. The control )'oom returns the compliment and favors his first band offering for the company with out­ sra nding sound. Holman's treatment of stand­ a rds assures a return visit, and be solos long­ in"ly on In A Senti1nental Moo(l. Conte C~ do1i, . Bill Perkins, Joe Maini, Jimmy Rowles, and Mel Lewis are among the Cali­ fornia jazz specialists who help out on such tunes as Shadl'ack, The Moon I s Blue, and Jnne Is B"s·ting Out All Ovel·. CHARLES A. ROBERTSON':: Tex Beneke: The Alamo Jackie Gl enson's mood n1hutns rack up en­ RCA Camden CAS655 STEREO viable sa les figures, yet in troduce such jazz Dutch Swing College Band: Twelve Jazz The Modern Jazz Quartet: Third Stream wOl'thies as Bobby Hackett and Lawrence Classics Perfect PS14038 B"own to people who might not hear them Music Atlantic SD 1345 otherwiRe. The meetings are usually carefUlly Besides presenting a good stereo spread, Jackie Gleason: Lazy Lively Love arranged, with the soloists surrounded only by these low-priced albums are durable and handy CapitolSW1439 circumspect- strings. If the truth were known, to bave about the house for the next dancing the rotund comedian long ago launched a party. In fact, Tex Beneke's selections from New jazz categ!lries are constantly being scheme to gradually increase tbe jazz content the Dimitri Tiomkin score probably will be thought up to soothe persons who like to claim of his offerings. One of his choice customs is played long after tbe film sound-track LP Is they never listen to jazz, and two of the most to engage a good group headed by Max Kamin­ forgotten. Arranger Ray Martin gives the more recent succeed in avoiding any u se of the sky, an unreconstructed Chicago-style trump­ fetching themes considerable space and a word. Efforts to combine jazz and classical eter, for a little travelling music to enliven rhythmic beat, with only a slight nod In the forms once were described adequately as his arrivals and departures on road trips. A direction of purely descriptive interludes. The chamber jazz or symphonic jazz, depending jovial host, he hates to think anyone is miss­ lad from Texas feels rigbt at home on the upon the number of players and decibels in­ ing the fun. vocals, still has tbe old Glenn Miller touch as volved, but both terms now are in disfavor. Just such a group goes to work on his latest leader, and plays free-and-easy tenor sax. Third-stream music, a substitute phrase which LP, and it stretches the mood category to the The Hollanders take up a stand midway Gunther Schuller coined and then introduced breaking point. Instead of a lone soloist in the between srtaight New Orleans style and the to the public In billing a concert of his works foreground, tbe massed strings compete with happy traditionalist sounds of their English laat May, is the latest vogue. Jazz journalists the full stereo spread of an uninhibited nonet. cousins. They play the regular dixieland book, Immediately saw magic in the words and are Something bas to give witb a front line ()f take a flyer at Ellington on Black And Tan reporting each development with all the avid­ Ruby Braff, Buck Clayton, and Yank Lawson Fantasy, and offer one 01' two originals, nota-· ity of fashion writers at a Dior opening. As on trumpet, Buster Bailey and Andy Fitz­ bly Mal-ch Of The Indi ans. Tbe clarinetist, the tag also is affixed to the Modern J azz gerald on clarinet, and Lawrence Brown on possibly the best to be heard the otber side Quartet's new album of works by Schuller, trombone. Gleason shows that he also can of Britisher Monty Sunshine, solos long and Jimmy Giuffre and John Lewis, with the prom­ turn the tension and relaxa tion trick, first eloquently. Tuba and banjo are arrayed In ise of more to come, it should remain in style programming such lazy melodies as Speak stereo to steady any faltering steps. until next season at least. Low, Lover Man, and It Had To Be Yo". Then Once the album title lures listeners with to leave tbe customers happy are such lively Stan Kenton: Live At The Las Vegas Tropi­ concealed leanings toward jazz, all three com­ alternates as Exactly Liloe Yo", Too Close For cana Capitol ST1460 posers are careful not to displease anyone. Comfort, and BI·eez·in' A long With The BI-eeze. Of course, a name like the Third Stream Quar­ The rhythm team includes Claude Hopkins, Only the rarefied atmosphere of Las Vegas tet might mollify some purchasers further, Al Caiola, and Milt Hinton, while the arrange­ could cause Stan Kenton to unbend enough to but very little in the way of jazz 'Is asked •. of ments are credited to George Williams. indulge in a little dixieland tomfoolery on a the group and it sounds even more subd·\!.ed As Gleason proceeded witb the plan to bring tune called Yo" And I And George, whicb al­ than usual. Mood music devotees in particulat jazz to the stage where it equalled or over­ lows the trombone section to run riot. And will find it restful when the Jimmy Giuffre balanced the mood .:porti'Ons on his LP's, he tbe paying customers are entertained further T bree joins in on two pastoral settings, both realized the end product would need a new as Billy Root wheels a rakish baritone sax devoid of disturbing animal life. Should the label. After llUlch scholarly research, he de­ througb Gene Roland's whimsical Puck's record fall Into hands of the more violent de­ cided the rigbt mixture would be called fourth­ BI·ues. Some degree of order is restored before tractors of the Quartet's previous work, they stream music. To arrive at this title, be was long, but the band continues to swing unre­ will be unable to apply their favorite epithet forced to look outside musical fields and in­ strainedly and does full justice to TIt-a:edo "pallbearers of jazz," as the corpse never ar­ vestigate thoroughly the .secret art of blend­ Juncti on, Sentimental Riff, and Ben.ie's Tune: rives this time. ing. It refers to the four main varieties of Soloists Lennie Niehaus, Jack Sheldon, and The longest and most interesting work is Scotcb, pot-still whiskies which Highlanders Richie Kamuca find their luck running high Oonversation, Schuller'S lone contribution, combine to produce the final harmonious and ride it to the limit. Capitol engineers turn which engages the Quartet In a clever dialogue article. in anotber fine on-location job, and tbe leader, with the visiting Beaux Arts QUartet. The Gleason's present concoction seems about in stereo, seems to hold the Tropicana audi­ classical contingent is given the dominant role right, and the next one may suit his stand­ ence right in the palm of his hand. for once, and supplies the excitement usually ards of perfection well enougb to wear the new asked of jazz players in a series of dramatic title in public for tbe first time. Wben that Interludes that resemble the climaXes of Bar­ happens, other entrepreneurs wbo hide jazz in J. J. Johnson: Trombone And Voices tok's string quartets. The two opposing forces mood settings are expected to reveal tbeir part Columbia CS8347 never get together for a joint statement, how­ in the plot. Among his fellow conspirators are George Shearing: The Shearing Touch ever, and the jazz group has the limited task Steve Allen, Arthur Godfrey, Michel Legrand, of resolving tensions already Introduced. The Paul Weston and Henri Rene_ Just so long as Capitol ST1472 Modern Jazz Quartet, which has resisted ef­ the strings hold up, a label which carries so If J ack Teagarden and George Shearing can forts of jazz copyists to ascend to the same many pleasant connotations should endure. cash in on mood albums, who will deny J. J. pinnacle, is reduced In this context to the Johnson the right to reap the profits from one emotional level of Martin Denny's group of Bill Holman's Great Big Band of his own? Frankly, ' tbe change of pace and South Sea I slanders. The exotic bird cries are Capitol ST1464 style on this LP gives the top-ranking jazz absent, but the presence of Ornette Coleman trombonist a chance to disclose aspects of his on another of Schuller's compositions should Between playing tenor sax on other leader's playing that are usually hidden. Cast as the correct that omission in the near future. dates and arranging chores for various bands, leading voice in a wordless choir wbich ar­ The packaging is just fashionable enough Bill Holman found time to assemble a big ranger Frank DeVol pipes in from various for people too pretentious to keep jazz about studio band and work out some of his writing points on the stereo stage, he adopts a bigger, the house under its proper name, with a cover ideas in his own way. Perhaps tbe best vindi­ warmer tone and drifts effortlessly through abstraction in Grand Rapids modern and im­ cation of all the effort is found on Spinuet, a Bernard Hermann's J ennie's Song, Motherles8 ported liner notes purchased from an English superb blues waltz that descends directly from Child, and In A SenUmental Mood. One or critic. The stereo engineering by Earle Brown Duke Ellington's scoring of the film "Anatomy two technical displays are set off to keep in and Franl, Abbey is faultless and comes from of a Murder." Holman arranged the theme trim, but for once Johnson's work Is charac­ Capitol studios. first as a background for Peggy Lee's lyrics to terized by Hoagy Carmichael'S Lazy Bone8. I'm Gonna Go Fishi n', then as a buoyant in­ George Shearing's supporting cboir on this * 732 The Parkway, Mamaroneck, N. Y. strumental for t he Gerry Mulligan concert occasion is composed of just strings, arranged " 68 AUDIO • FEBRUARY, 1961 ... A SPECIALLY COMMISSIONED LIMITED EDITION RECORDING ... "The Orchestra .•. The Instruments" No. LS661

Without a doubt, the mos~ ambitious, musically sound, entertaining and informative privately commissioned stereo recording to date. SuperbJy original in concept, extraor­ dinary in scope, it shows how each instrument (and instru­ mental choir) emanates from the orchestra in the correct spatial relation to all other in­ struments. Supervised by Dr. Kurt List, winner of the Grand Prix du Disque, renowned com­ poser, critic and Musical Director of Westminster; recorded by the Vienna State Opera Orchestra in the acoustically brilliant Mozartsaal con­ cert 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 ,

• I Shure Stereo products: \ You will receive the Westminster/Shure recording at no charge with the purchase of a Shure Profes­ sional 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 Profes­ sional Tone Arm (Model M232 $29.95, Model M236 $31.95). All prices audiophile net. '

Music lover's record . selection booklet ... Offer limited. Send "Customer Comment Card" tells how to preserve (enclosed with product) and sales slip to Shure. See record fidelity, explains your local high fidelity dealer. (Listed in Yellow Pages hi-fi stereo. under "High Fidelity," "Music systems-home".) Send 25¢ to: Shure Brothers, Inc. 222 H artrey Ave. Evanston, Ill. D~pt. LLL

AUQIO • FEBRUARY, .lQ61 in number~ ample enough to assure a plump that most audiences know the arrangements band tour, comprise the bill of fare which tltereo .nllnd by an eqllally large-III'opo"tiuned well enough to compensate for any lIIi~sing lists jJf eet B enny Bailey, For Lena And nilly ~Ia~', _\ dllzen themes assol"int('d WI! h pa,'ts, they depend for ~upport sol e l~· IIpon the Lennie, and Horace Silver's Doodlin.' College other k('~'h"'!rd notables rpceive the ~hearing Ike I~anc~ trio. tbeir regular R..ccotllJlan)"ing students should find something in the lyrics tOllch. Inrlll1t the conclu,ion of the projected series Lambert, Hendricks And Ross Sing Elling. section \Vo,'\<. a.fter a('tual instrulllPnts are is anybo

This is one of the two speakers in the KLH Model Eight FM Receiving System. Its precisely controlled motion over a great distance KLH RESEARCH AND DEVELOPMENT CORPORATIOn helps to account for its remarkable performance. :10 CROSS STREET. CAMBRIDGE 39. MASSAC,HUSETl'S

We hope there is a place in your life Descriptive literature, with the name of your nearest franchised J( LH dealer, for a KLH Model Eight. is available on reqllest,

70 AUDIO • FEBRUARY, 1961 The touch of Murray G. Crosby has created a truly remarkable 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 con­ trol this magnificent component is sheer .simplicity. Wherever possible ganged, push-pull knobs are utilized. Source selec­ tion is achieved through push-buttons. Visu­ ally, the R80 is exceptionally pleasing and compact for custom installations. The hand­ some 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 in­ cluding a Multiplex Dimen­ sion control and powering facilities for a non-powered accessory Mul­ tiplex 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 value­ setting $375 .

• 'r .w.~ 1 l - .,...- #' i ~-..u.- _lot ~~

- . CRO'5BY R80 RECEIVER. 161!z" W. x 5¥s" H. x 14Y," D. OPTIONAL WOOD OR METAL CABINET AVAILABLE.

Crosby Electronics, Inc•• 135 Eileen Way· Syosset, L.I., N. Y. Manufacturers and designers of stereophonic components, stereo BY Crosby speakers and the Crosby Compatible Stereo FM Multiplex System.

AUDIO- ' FEBRUAR~ : '191)1 71 pany's Super Stereo series, the only doctoring locking grooves are silent. The more experi­ complaint. She aims at nothing less than the administered is a microscopic examination of enced should have a fine time adding reverber­ top, drawing responses of similar loftiness some sounds that are ordinarily heard in ation to some episodes, or altering the per­ from tbe likes of Ray Nance, J ohnny Hodges, noisy su rroundings. A door creaks at a ghostly spective on others, depending upon the con­ Ben Webster, and Mel Lewis. The Elling­ touch, while a n air hammer and compressor text in which the material is to be employed. tonians do well by D ay D,·ea1ll, with John blot out passing street traffic. Only the op­ Science fiction fans are hereby alerted that the Latouche lyrics, and other tu nes associated erators, live or ethereal, would stand as close next chapter deals with Outer Space, but the with their employer, while the singer recalls as the microphones are placed. If anyone end is not yet in sight. her Dorsey days on For You, What Oan 1 Say wants to know pow it feels to go through a After 1 Say I'lIl Sorry, and D,·earn Of You. pane of glass, the experience is right here Another Dorsey alnmnus, Frank Sinatra, waiting and nothing softens tbe blow. In these Jo Stafford: Jo Plus Jazz might try Mandel's brand of swing for a cases, the avowed purpose is to present effects Columbia CS8361 change. in the purest state possible, before they be­ Kay Starr: Jazz Singe r Capitol ST1 438 Kay Starr nearly qualifies as a jazz singer come diluted or diffuse. Crowd noises, zoo ani­ wbatever tbe context, but her break with the mals, and the blast of an ocean liner are At a time when few female jazz singers are popular idiom sounds a little tentative, almost recorded at a more normal distance. Consider­ worthy of the name, tbe arrival of two vocal­ as tbough Capitol wanted to look at the sales able patience and know-how is devoted to mak­ ists from the popular field is a welcome event. sheets before allowing her to go further. ing each come alive with stunning realism. It becomes doubly so when the visitors call on Alexander gives her a chance to try her luck The listener who wants a succession of the respective alTanging and conducting tal­ on a variety of settings, spotting an electric spectacular effects in rapid order will find the ents of Johnny ~Iand e l or Van Alexander, who organ or singing ensemble on some, and using grooves between bands locl,ed, and the pickup supply rugged t e ts of a singer's ability. J 0 a big swinging band on others. A good indi­ must be moved each time. A boon for home Stafford is able enough and knows as much cation of what she could accomplish with an tape enthusiasts, this safeguard frees both abou t the art as a nyone else. If tbe accom­ Ellington contingent , or at a reunion with hands for use in manipulating a tape machine · panying g l· oup sli ghtly overshadows ber, Charlie Barnet for that matter, occurs on and introduces no unwanted noises as the neither she nor the listener has reason for 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 Victor LS06007 Now that Carnegie Hall is safe from would­ be 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 prede­ cessor. 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 this 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 engi­ neered last year's concert, sees that none of it is lost on the stereo version. MONO Bl ind Gary Davis: Ha rl em Street Singer 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 cheer­ ful 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 elec­ tro!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 times, .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 wed­ dings between gospel · and blues, he might

72 AUDle·-·. FEBRUARY, 1961 adopt a pseudonym and preside at a few legiti­ mate 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 van­ ished 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. Years spent in the open have made his voice rough and leathery, yet it overlJows with compassion and seems to bear a person­ nal message fo r each member of his small circle of listeners. He takes his song-sermons into Harlem storefront churches on occaSion, but lofty pulpits and large congregations ------> would be unsuited to his homely parables. Davis marches along in the tradition of Blind Willie Johnson, wh o recorded in Dallas for Columhia in 1927, and revives the legend­ '-- ~ , ary Texas singer's interpretation of the Sam­ son and DeUlah story, along with his Twelve ---- -""':"" -7 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 reveal­ ing period in a player's career occurs shortly before the heavy hand of public approval rests on his shoulders, and these co\lpctions of his­ torical reissues cover just that interval in the lives of two renowned swing-era leaders. Rfandbero SERIES 6 Bunny Berigan, in the opinion of many, did his best work before the burden of maintain­ ing 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 num­ STEREO TAPE DECK bers recorded with small pick-up groups. His ballad'style is beautifully relaxed, making it a . joy to revisit such old tunes as A. Melody In '['he Sky, and I Neat'ly Let Love Go Slipping a superior in stru ment! 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 Charlie 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 He re's why •• • , $498 enough to hold a certain charm, and Miller always played for dancers. • R ecor ~ ing head gap at .00052" w. to r deeper, wider, cleaner signal Jim Copp and Ed BTown: Th imble Corner impressions on .tape. ' Playhouse 303 • Playback head gap at .00012 " w. assures optimum perfo rmance A clanging trolley bell signals the start of and higher frequency response. the glorious sound effects which set the two • Erase and record heads completel y self-demagnetiz ing. previous , LP's in this series apart from the ordinary children's release. Two Los Angeles • !leads laminaled wilh special lines! grade Mu melal fo eliminafe bachelors, J im Copp a nd 'Ed Brown, spend the stray field disiortions:' better part of a year on each, creating a spe­ • Record and playback heads each have' lotal of 2,500 windings­ cial little world "for small fry and sophisti­ with each winding '/2 the thickness of a human hair. cated adults" to share together. Copp is re­ sponsible for the songs and stories, while • Head cleaning remarkably simple and easy. Brown designs the distinctive covers and joins his partner in playing numerous roles. The All Tandberg un its feature 1W' ips wonderful people and animals that inhabit "The Professional'S Speed 01 the Future" Thimble Corner make it a funny place, and fortunate listeners will meet a talking ducl{, TANDBERG 6 STEREO TAPE DECK also offers these outstand ing a turkey dressed in satin, Anderson cat, and performance featu res: the dog t hat went to Yale. 'Each personality is developed by characteristic sounds as well Sound·on·sound; 4 tr ac k and 2 Irack slereo & monau ral playback; as words, and just a few of those described 4 Ira ck slereo & mo na ural re cord; Bu ill·i n remote conlrol ; Digital are Harrison Garrison, Luck Gluck, Thaddeus counler; Silenl pause conlrol ; Direct monitor from signal source or Hop, Hooligan Flea, and the dog with the acl ive recording ; Push bullon operati on. longest name in the world. A return visit is paid to Miss Goggins, whose teaching methods are the despair of all modern educators. The annual release is timed to catch the Christmas RJandbcJ'8 of America, Inc. trade, but better shops should keep copies on hand for birthday gifts. .IE a Third Avenue, Pelham, N. Y.

AUDIO • FEBRUARY, 1961 '73 NEW PRODUCTS • 72-Watt Amplifier Kit. Taldng its place on a single mounting p late. Designated as Priced at $99.95 the JanKit 41 comes with beside the ullusually weIJ-designed H. H. Model PK-449 they are priced at only CnmlllE'te instructions for building an In­ Scott FM tuner kit is this 72-watt ampli­ $49.50. The tUl"ntable features a heavy expen>"lve, shelf-type enclosure or for fier kit, the Scott LK-72. On the surface duty 4-pole induction motor, free floating mounting in existing cabinets. Neshamfny this kit seemS to have a IJ the virtueR of "nd Rhock moullt ... d tn e lil11111 ate vibration. Electronic Corp., Neshaminy, Pe1lna. B-4 the tuner kit-that is extreme simpliC'ity The 3-pound. rim-weighted, 12-inch alumi- for the kit builder combined with factory • SO-Watt Stereo AmpUfier. Sherwood's performance standards. From the way - -~ !l1"del S-5000 II is an 80-w"tt (muRIc these kits go together it seems that the p"wer) stel'eo amplifier and preamplifier designer was ordel'ed to remove the drudg­ and I" an improved model of the Sherwood ery and leave only the cost-saving fun. In S-5000 The S-5000 II provides eilher appearance this amplifier is a pE'l"fE'ct /' stel'eophonic or monophonic system opera­ match for the tuner kit so that the builder ,;;.- tinn 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\vitc h, and dual amplifte l ~ mono­ phollic operation with either set of input !,OlJr'·.,,,. 'rhe five modes of opf'rntlon

nllm table is constructed with a perma­ nently lubricated oilite bronze bearing while the spindle turns on a single ball beal"ing. Speeds are selected by means of a clicl,-in shift lever and the idle r is dis­ engaged 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 (stereu, stereo-revel'sed, n10no 1, mono 2, with wow and flutter less than 0.2 per n,ono 1 + 2) are selected by a function cent. The 12-inch tone arm is easily ad­ switch which also operates a correspond­ justed for different stylus forces by me" ns ing group of indicator lights to identify of a knob at the r ear of the arm. Addi­ the selected mode. Other features include may have a system which is matched in presence-rise switch, phono chamlel hum appeamnce a" weIJ as perfnl'mance by the tional features incl ude a plug-in h ead and an ON/OFF switch located In the a rm a lld noise 60 db below rated output, and time he Is finished. S.peciflcatioll!" for the phono Rensitivity of 1.8 mv. Thel'e is also LK-72 read like those for any factory-as­ rest; simply lift the tone arm to start the motor and replace in the arm rest to stop a "third channel" output. Price is $199.50. sembled unit: fuIJ power 72 watts (36 Sherwood Electronic Laboratories, Inc., watts per channel); IHFM power band it. Supplied w ith a strobe disc, 45-rpm adapter, shielded hook-up c"bles. Lafa­ 4300 N. California Ave., Chicago 18, extends down to 20 cps; total harmonic Illinois. B-5 distortion is less than 0.4 per cent at full yette Radio Corp., 165-08 Liberty Ave., power; hum level is better than 70 db be­ Jamaica 33, N.Y. B-3 low fuIJ power output. Among the many • Electrostat-2 Full-Range Speaker Sys­ additional features of the LK-72 are a • Speaker System Kit. Solving the per­ tem. Io'eaturing a 4-element eleetrostalic "center channel" level control, scratch plexing problems of enclosing e lect rosta­ tweeter, the new Electrostat-2 introdlJced filter, tape recorder monitor, and separate tics or of finding a woofer whose efficiency by Rll(\io Sh"ck of Boston is intended to bass and treble control for each channel. and sound "character" m"tch the electro­ provide good sound quality at a reason­ The H. H. Scott Model LK-72 I'etails for static units, the new JanKit manufactured able price. The highs in thi" full-range $149.95. H. H. Scott, Inc., Dept. P, 111 by Neshaminy Electl'onic Corp. contains system, as previously indicated, are Powdermill Road, Maynard, Mass. B-l an electrogtalic mid- and high-range h" nelled by a 4-element electrogt" tic sp.,,,ker, it" power supply, a nd a matching • Unique New Mixer. UltrAudio Products, woofer-all pre-mounted on a rigid 19 'h . a division of Oberline Inc., has Introduced a mixer amplifier offering features herE'to­ fore unavailable in either professional or home units. Designated Model M -5 Custo­ Mixer 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

tweeter which is placed so that a 120-de­ gree 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 control, with high and low impedance in­ thE' highs. An ON/OFF switch is provided puts and output, illuminated VU meter, to control the electrostatic element. Fre­ turntable cueing, and equalizing. The mixer quency range is stated as 30 to 25,000 cps utilizes a standard 5 'A, x 19 in. panel, for the system. Power handling capacity weighs but 20 pounds, complete with self­ is 20 watts, impedance is 8 ohms. In addi­ contained power supply. Special features tion the Electrostat-2 is available in a al'e the plug-in input transformers and by 16 inch pa.nel designed for custom in­ choice of two decorator cabinets: genuine preamps which one buys only if needed, stallation in a location of your own choos­ mahogany or imported teak. Radio Shack and the patented "Straight-Line" volume ing. Mid- and high-frequency reproduction Corp., 730 Commonwealth Ave., Boston 17, controls. Replaceable designation strips in the JanKit 41 comes from a J anZen Mass. B-6 permit indication of which source is con­ electrostatic speaker whose two push- pull nected to each mix position. UltrAudio radiators are stated to produce uniform • Economy Tape-Head Demagnetizer. A Products, Dept. P-1, 7471 Melrose Ave., frequency response from 700 to beyond new economy priced tape hea d demagne­ Los Angeles 46. B-2 30,000 cps. Bass Is provided by a Nesha­ tizer which will remove permanent mag­ miny Model 350 ll-Inch woofer. This netization-a significant cause of h;gh • 4-Speed Transcription Turntable and highly compliant speaker is specifically noise level and harmonic distortion-has TOLe Arm. Each unit engineered to com­ designed to match the J"nZen electrostatic been announced by Robins Industries. plement the other, Lafayette's new 4- and tt.. retain full efficiency down to 30 Known as Model HD-3, it features a spe­ speed turntable and tone arm are supplied cps in enclosures as small as 2 cubic feet. cial plastic sleeve on the tip of the probe

74 AUDIO • FEBRUARY, 1961 BREAKTHROUGH DBRI(JH!

Ne w LK- 72 72-Wa tt stereo complete amplifier kit (left), $149.95. LT-IO Wi de -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, HERE'S WHAT ENTHUSIASTIC OWNERS SAY: for the first time, are kits with " ... designed to professional sta nd­ tried to adequately state how I feel t he performance, features and ard s; sou nd abso lutely clean, very about this tun er .. ." - Samuel R. handsome good looks of H. H . se nsi tive; instru ction book of out· Harover, Jack so nville, Ark. standing clarity." - Major B. W. Scott factory-assembled com­ Cotton, Jacksonvi ll e, Ark. " . .. without a doubt the easiest kit I ponents ... kits that are a real have ever built (out of 11 ) ... " - B. " Loo ked long for the be st ki t- and P. Loman, Jr. , Rochester, N. Y. pleasure to build and so ex­ found it ... bes t instructions I ever pertly designed that you can saw, unbelievably simpl e to build." - " . . . fines! kit I have eve r bldl!. And M. Greenfield, White Plai ns, N. Y. one of the fine st tuners I have heard, achieve professional results in kit or otherwise." - -A. J. Zilker, just a few hours. " . . . I woul d run ou t of su perlati ves if I Hou sto n, Texas. H. H . Scott assures you the performance of factory-built units with these innovations: 1. All mechanical parts such • " < H.H. SCOTT as terminal strips and tube --H. H. Scott Inc., III Po wdermill Road, Maynard, Mass. sockets are firmly pre-riveted to the chassis thus assuring sturdy professional construction and eliminating the bother Rush me complete technical specifications on H. H. Scott kits. of this time-consuming operation. Include your new "1961 Guide to Custom Stereo." 2. Every wire and cable is already cut to exact length and pre­ Dept. 035-02. stripped. This saves you time and assures professional per­ l\Tan~e~ ______formance because exact lead length is automatic. 3. To take the guesswork out of assembly, electronic parts are Address' ______mounted on special cards in the order in which they are used.

No loose bags of parts to confuse you. . City______Zone __~S tale ______4. Full color diagrams in easy-to-follow instruction book *Pr-ices slightly higher West oj Rockies. simplify assembly and reduce errors because you match t he. part to the color diagram. Export : Telesco International Corp., 171 Madison Ave., N.V .C. that prevents accidental scratches to the • New Erase Heads. The Nortronics Com­ life, low tape f riction, and freedom from tape. The spec ially shaped probe m akes pany h as ann ounced a n ew line of stereo oxide loa ding . The heads are ava ila ble in any head accessible and the HD-3 ca n be and monophonic erase heads for u se w ith two impedances: the No. 1 high impedance used equally well for both monophonic or two- and four-tracl, magnetic tape ma­ head requires appI'oximately 115 volts at stereophonic tape h eads. Claimed to be the chines. Three basic mounting styles facili­ 60,000 cps; the No.4 low impedance model first quality, low cost, A merican-ma de t ate the installation of the HQ series operates with 35 volts a t 60,000 cps. heads in a ll types of t a pe recorders. Further information and specifications from The Nortronics Company, Inc., 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, mag­ netic cartridge, cera mic or crysta l cart­ ridge, tape head, or prea mplified tape. Con­ demagnetizer, the HD-3 is priced at .$5.95 Double-gap constru ction is u sed for clean erasure with minimum power require­ trols include selector switch, tape monitor which Should make it very attractive t o switch, sepa rate level and balance con­ ments. The tape comes into contact with amateur tape fans. Robins Indus tries trols, balance check switch, scratch and Corp., Flushing 54, N. Y. B-7 only the polished metal face, givin g long rumble filters, loudness-level switc h, and individual feedback-type bass and treble 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 ereXII

and a g.peaker Phase rever;:;al . switch. Fre­ quency 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 cent from· 25 to 20,000 cps. The dual power amplifiers of the ST40 are Williamson-type circui ts employing voltage am.plifier s a nd split-load phase inverters driving the out­ put 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 in­ c lude metal cover. Eico Electronic Instru­ m ent Co., Inc., 33-00 Northern B lvd., L.I.C. 1, N.Y. B-9

• Stereo Receiver. Following the same de­ sign principles as the Fisher Models 600 and 800, the new 500-S, priced a t $349.50, is Fisher's a nswe r to the need f or a qual­ ity FM-AM stereo receiver at a rela tively High gain .. . low noise ... absence of microphonics ... low modera te cost. The 500-S is a completely distortion ... reliability - these are the primary qualities integrated system of m a tched Fisher c om­ circuit designers look for in electron tubes. Once again, ponen ts on one chassis. All tha t is re­ Harman-Kardon engineers have found these qualities quired for a complete system is a pair of speakers and a record player. Sensitivity best exemplified in Amperex tubes. Small wonder, then, of the FM tuner is 0.9 microvolts for 20 that the tube complement of the new Harman-Kardon db of quieting with a 72-ohm antenna ; "Stereo Recital" Model TA224 Integrated Stereophonic 1.6 microvolts with 300,ohm antenna. Receiver includes four Amperex 12AX7/ ECC83's, one 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 r e li abi l~ty and unique design advan­ tages in the world's finest audio components. about hi-Ii tubes Applications engineering assistance and detailed data tor hi-fi circuitry are always available to equipment manufacturers. Write: Amperex Electronic Corp., Special Purpose Tube Divi­ sion, 230 Duffy Avenue, Hicksville, L. 1., N ew York.

OTHER AMPERE X TUBES FOR QUALITY HIGH-FIDELITY AUDIO APPLICATIONS

POWER AMPLIFIERS RF AMPLIFIERS INDICATORS 6CA7/EL34 : 60 w. di stributed load 6ES8: Frame grid t win triode 6FG6/EM84: Bar pattern 7189: 20 w., push·pull 6ER5 : Frame grid shielded triode 6BQS/EL84: 17 w., push·pull IM3/0M70: Subminiature "excla· t h e desired volume level at a ll times. The 6CWS/EL86: 25 w., high current, 6EH7/EFI83: Frame grid pentode mation " pattern a udio control center h a s a tota l of twenty low voltage for IF, remote cut·off controls and switches, the controls being SBM8/ECL82: Triode-pentode, 8 w., 6EJ7 /EFI84: Frame grid pentode SEMICONDUCTORS grouped functionally to make ope r a tion push·pull for IF, sharp cut·off 2N1517 : RF transistor, 70 me simple for even the "uninitiated." The 'SAQ8/ECC85: 2N1516: RF tranSi stor, 70 me dua l-channel power amplifier supplies 45 VOLTAGE AMPLIFIERS Dual triode for FM tuners 6267/EF86: Pentode for pre·amps 2N1515: RF transistor, 70 me watts-music power rating. There are 13 60C8/EBF89: Duo·diode pentode 12AT7 /ECC81: 1Twin triodes, low INS42: inpu ts and 5 outputs on the rea r panel, 12AU7/ECC82: hum, noise and RECTIFIERS Matched pair discriminator including a "center channel" output. The 12AX7/ECC83: microphonlcs diodes Fisher 500-S is 17 inches wide, 4 13/ 16 6V4/EZ80: Indirectly heated, 90 mA SBL8/ECF80: High gain, triode· IN87A: inches high, and 13 % inches deep. Fisher pentode, low hum, noise and 6CA4/EZ81: Indirectly heated, 150 mA .AM detector diode, R a dio Corp., 21-21 44th Drive, Long microphonics SAR4/G134: Indirectly heated, 250 mA subminiature Isla nd City 1, N .Y. B --IO

76 AUDIO • FEBRUARY, 1961 NEW LITERATURE • Pocket"Size Aid for Planning Stereo knig1!!:,kit® System. Pickering & Company has just published a b roch u r e en titled "Tech­ Specs" which was written and design ed a pleasure to build and you own the best to assist t h e a u diofan in p lannin g a s t ereo high-fidelity system. Pocket -size, "Tech ­ Specs" is a g u ide w h ich h elps p la n for you get more with a Knight-Kit: needed space and coor dinates the com­ ponents to the enclosur e or cabin et. Con­ custom quality ... exclusive design developments ... tents include a p lanning chart and com­ plete technical specification s of the line maximum savings ... supreme listening enjoyment of Stanton Stereo Fluxvalves. Available at no cost by writing to D ept. PR6, P ick­ ering & Company, Sunnyside Bou levard, Plainview, New York. B-ll • Allied's 1961 High-Pidelity Catalog B eady. Allied Radio a nnou nces the avail­ ability of its 196 1 catalog. Consisting of 444 pages it list s more than 40,000 items. I n a ddition to Allied's own Knight line of components a complete line of other fam­ ou s brand names are included. F eaturing extensive lis tings of componen ts, the a l­ lied catalog a lso includes a wide selection of complete systems. "Do-i t-yourself" en­ thus iasts will find a greatly enlarged selection of Knight-Kits. I n cluded are basic amplifiers, stereo and monophonic amplifiers, preamps, tuners, a uni versal stereo tape recorder-playback preamp, a nd speaker enclosure kits. A complete selection of fur niture to house a ll high­ fi delity components is fea t ured in this year 's catalog. A lso included are listings knight-kit Stereo Tape Record-Playback Preamp Kit of specially selected s t ereo r ecords a nd new Complete record-playback preamp for any 2 or 3 head stereo tape transport. recorded tapes. T his catalog is avail­ Separate dual-channel recording and playback preamps. Permits tape able without char ge upon r equ est. Write and monitoring, "sound-on-sound" and "echo" effects. Features : Accurate VU to Allied R adio Corp oration, 100 N. West­ meters; adjustable bias and erase voltages; concentric clutch-type level controls ern Ave., Chicago 80, Ill. B-12 exclusive 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 • Loudspeake·rs and Equipment Cabinets. L isting their complet e line of h igh-q ua lity possible stereo and monophonic function. Printed circuitry for easy assembly. speakers, speaker systems, equ ipmen t Extruded aluminum panel in Desert Beige and Sand Gold; 4Ys x 15 )1, x 9". cabinets, a nd crossover networks, this Shpg. wt., 15 Ibs. 83 YX 929. $5 Down. Only $79.95 (less case). new brochure f.rom R . T. Bozak Sales Company provides a compreh ensive de­ scription and t ech nical specifications of wide choice of money-saving stereo hi-fi knight-kits a ll t h e products listed. Free copies m ay be obtained from any Bozak dealer, or by writing to R. T . Boza k Sa les Compan y , Darrien, Connecticut. B-13 • New Jense·n Loudspeaker Ca.talog. A 24- page loudspealoboes, oboe d'amore, bassoon, 3 • trumpets, 2 French horns, timpani, harpsi­ • Perfect timing chord and organ. The ·chorus numbered 225. No change in tape speed Mr. Randolph nevertheless struck a happy • balanr,e between the two forces. from start to end of reel It was a distinct p leasu re to hear this 2 separate channels well-rehearsed, rarefully disciplined ehorus • reach the point in the rehearsal at which Provision for installation the music took over and all sang as one. • of a synchronizing head This fusion of voices is possible more often when a choir sings for its own leader than • Portable or rack mounted when it is imported by an orchestral con­ Sound-on-sound ductor for an occasional concert. "Members • (of a chorus) ," wrote Virgil Thomson (in • Echo chamber The New York Herald Tribune, l\Iay 9, plus many more features. 1943), "will sing in pitch and in tune (for • the latter, nnli) will obey him with vigor Write for bulletin No. 1 and all promptitude. But their work will not have the poetry, the personnlity, the M 0 V ICC 0 M PAN Y, INC. . E'xpressive variety that it has unller the 12432 SANTA MONICA BLVD. LOS ANGELES 25, CALIF. ~ man they are used to, the man with whom they have an accustomed spiritual inti­ Circle 78B macy." IE 78 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 con­ trol 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 be­ come necessary due to a future acquisi­ tion of a multiplex unit, the sum of less than $5 (coupled with a morning's ef­ fort) 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 oc­ cupied by a patented, slide-out, record storage rack (Fig. 6). The space avail­ able 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 pos­ sible tape instrument is obviously con­ fined deep in stllge one! SARKES Lastly, several features were incorpo­ rated which are well nigh invisible, but TARZIAN do much towards adding convenience and mobility to the entire system. Previ­ ously mentioned, there is the inclusion TAPE of the sliding record rack. In connec­ Engineered for Highest Fidelity tion with the turntable compartment, looking at Fig. 7, one notes the use of a lallip. This lamp is automatically • Here is a tape that you can safely (and switched by a push-pull pressure switch High Output-can accept signals wisely) adopt as your personal "stand­ operated by the door closure. This fea­ with dynamic range to realize the ard" tape. It is a professional quality tape ture was added at very reasonable cost full potential of even the finest that carries the same list price as many professional equipment. when I discovered a General Electric Co. • tapes of inferior quality. Consider that automatic closet lamp fixture for under Wide-Range Response-virtually inferior tapes frequently damage record~ $2.00! In conclusion, the entire console flat response for all recording fre- quencies. ing heads by abrasion; that their con~ (in operating rondition weighing some • tinuous flaking reduces recording-head 200 pounds) is mounted on four 2-inch Low Distortion-distortion is less sensitivity; that the quality of sound is rubber tired casters so that the efficient than 2Y,% at maximum record level evidently poor even on immediate play~ housewife is not hampered in her tidy­ as measured by Navy Specifica­ tion W-T-0061 . back and that it rapidly deteriorates fur~ ing up. The console rolls quite easily at • ther in storage. Compare the quality char~ such times! High Uniformity-uniformity with­ Many excellC'nt treatises are availahle in a 1200-foot reel is within plus acteristics of Tarzian tape listed at left. on the manner and methods of wood or minus X db. A new oxide for­ Tarzian tape makes every tape recorder mula and special selectivity of finishing. The only comment necessary oxides protect recording heads perform at its very best. Prove this to here is that the basic ingredirnt needed from wear and prevent abrasion. yourself with your personal listening test. to acquire that professional hand-rubbed • There's a written guarantee in every box! look so desired by all, is simply hand Humidity and Temperature Pro­ tection-special coating, prim­ Ask your dealer for Tarzian tape. If he sanding and polishing! No smnll con­ ing, and binding techniques help cannot supply you, send us his name, tribution to the sheen of the final finish, keep Tarzian tape in new condi­ · were the long hours sprnt sanding and tion longer in ordinary good tape · and we will see that your needs are polishing (with 4-0 steel wool) the un­ storage conditions. · promptly supplied. stained raw wood. This was an extra ...... •...... •..•.· smoothing operation in addition to the · polishing done after staining and be­ tween each of the three successive coats SARKES TARZIAN, INC. of lacquer. The whole ensemble is World's Leading Manufacturers of TV and FM Tuners. Closed Circuit TV Systems. Broadcast stained a platinum walnut. The color of Equipment. Air Trimmers. FM Radios. Magnetic Recording Tape. Semiconductor Devices this stain is beautifully enhanced by this MAGNETIC TAPE DIVISION. BLOOMINGTON. INDIANA lengthy but rewarding process. Export: Ad Auriema, Inc., New York

AUDIO • FEBRUARY, 1961 79 PERFECT IIHEARJJ-PHONES

THE BEYER DT 48 DYNAMIC HEADSET.. . FOR DisTORTION ...... ""­ FREE REPRODUCTION OF SOUND ... EVEN AT HIGH t LOUDNESS LEVELS ... RESONANCE FREE THROUGHOUT Fig. 6. Record storage now-tape re­ corder later. THE RANGE OF HEARING FROM 20 TO 15,000 CYCLES.

THE"" EAF=lPHONES TO MAKE YOU WANT EARPHONES It is rather evident- that there has AGAIN. been a deliberate attempt on the part of the author to minimize the description COMPLETE SPECIFICATIONS WILL BE PROMPTLY and attendant elaboration on detail. This FURNISHED ON REQUEST. 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 GOTHAM AU D I 0 CORPORATION tailor his design to his individual speci­ cations, both in choice of instrumenta­ 2 WEST 46th STREET, NEW YORK 36, N. Y •••• COlumbus 5-4111 1710 N. LA BREA, HOL.L.YWOOO 28, CALIF•••• HOllywood 5-4111 tion and decor. Very briefly: The au­ thor's console scales 50 inches long, 30 inches high, and 23 inches in depth, The First Book of its Kind-No Other Like Itt- while the speaker enclosures were modi­ fied (in decor only) from factory plans included with each speaker component kit. SOUND in the THEATRE The solutions presented herein, par­ by Harold Burris·Meyer and Vincent Mallory ticularly that of laminated case con­ struction, are sufficiently adaptable to othing like SOUND in the THEATRE rived systems and equipment specifications. permit their inclusion in the majority N has ever been published. It is the first Complete procedures are given for: Planning, of instances where the audiofan is de­ book to set forth in authoritative detail what assembling, and testing sound control installa­ you can do with sound by ' electronic control, tions-Articulating sound control with other sirous of having the type and quality and how to do it whenever the source (singer, elements of production-Rehearsals and per­ of furniture housing that will be com­ musician, speaker, etc.) and the audience are formances - Operation and maintenance· of mensurate with the quality of his care­ present together. The book develops the re­ sound control equipment. f ully chosen components. It is hoped quirements for electronic sound control from the necessities of the performance, the char­ THE AUTHORS that the methods of achieving this cus­ acteristics of the audience (hearing and psy­ During the past thirty years, the authors have developed tom look as presented herein may satisfy choacoustics), and the way sound is modified the techniques of sound control in opera, open·air amphi­ his needs and desires, while consuming theatres, theatres on Broadway, theatres on·the·road and by environment, hall, and scenery. Sound less of his exchequer than were he to sources are considered for their susceptibility off·Broadway, in concert halls and night clubs, in Holly· wood and in the laboratory. Some of their techniques are purchase the equivalent in the trade ~ of control and need for it, and the many tech- used in broadcast and recording as well as in perform· III J£ I " niques for applying electronic sound control ances where an audience is present. From their laboratory arts. " are described and illustrated in thirty-two spe· have come notably successful applications of sound con· ~fiC pr~blems . From these problems are de- trol to psychological warfare and psychological screening. " ' ' ~~--~~! I'-----~ I

RADIO 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.) Fig. 7. The turntable-with an automatic lamp to light the way to the.-sF'lindle. Nama ______~------Address ______. ______City ______Zone _ Slale ______.______"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 al­ Altec 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 expen­ through. 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 gen­ pli1ier is used, its input fed from the erally unheard-of when the Dyers High end of the Heathkit electronic wanted concert hall realism: For an­ crossovek-. ,and its output feeding the other, Mr. Dyer, i:easoned: why not uti­ 302-A through a Jensen network with lize the available speakers and equip­ a 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 com­ ing level ·of the corner to the far right bined with the latest. Possibly the sys­ of . 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 surfaces. techniques that are, and in all art should Feed for the midrange horn was taken be, not the end but the means to it. from the High output of the Altec cross­ In that respect this installation has over 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 directed to the midrange ·horn.· and inspiration of many a professional System response ~ Here it is, per endeavor. And here, heard on this unique

Fig. 7. Frequency

AR-1W response of the 6 ALTEC 285 speakers. AL9Ec 515 V D I AL TEC 604(W) ALT~C lOl(TW) ...... JENS'EN 302A" V

2...... 20000 1000 10000 FREQUENCY I N CYCLES PER SECOND

AUDIO • FEBRUARY, 1961 ~ystem in the cozy livingroom overlook­ 'ng the mountains, the cottonwoods and Key Position with IBM in ' he river, the masters of music come ITuly into their own, with pre~ence, fi­ lelity, dpfinition and perspective ahout AUDIO AND which nothing of the ersatz is discern­ ible. IE MAGNETIC TAPE SYSTEMS Primo Dynamic Microphone is now being used by 70 96 of general TAPE GUIDE DEVELOPMENT t ape-recorder manufact urers in (from page 34) Japan and gaining a hig h reput· An important position has recently negative-going voltage at the plate of been created in the advonced devel­ opment of audio equipment, including V I1 which is transf('rred to the grid of high· fide lity magn tic tope systems. V 2 ) causing the plate of V! to go posi­ This opening carries significont re­ munerati""J n and could lead to full tive. The vo ltage fed from the platp of responsibility for all development ef· forts in these areas. V 2 to the grid of V j is therefore of the same polarity as the original signal on An engineering team, now being formed, will be charged with the reo this grid; feed hack is positive. The same sponsibility for applying latest technol­ is true for the voltage fpd from the ogy to high-fidelity oudio and mag­ netic tape systems of the future. The plate of V j to the grid of V!, How­ group will function in an atm:>sphere ever, the voltages on the grids of V I highly receptive to new approaches which may accomplish major break­ and V 2 are of opposite polarity, so that throughs in systems of this type, Amona the every kind of dynamiC microphone units one triode is in the positive half-cycle we are selling the OM-3. DM·4 art' one of the mos>l Experience in the audio or mogne tic p opular. This rully cxc.c:lIcn t microphone units .ne while the othpr is in the negative half. tcp4'> ·recording fields is e~sential. In now brina insb.llc.d into the microphont cases of the addition, '>ome experience in transistor B-plus is supplied to the plates of V I majority of ~~ recordcr manufacturers In Ja~n . circuit design is desirable. Education rc..su1tine in a complete a nd perfect tap" recorde-r and V! through the center-tapped coil, mu , t include on MSEE or GSEE degree microphone. Frequ~ncy responcc: 70 10.000 cis ±3 dB with related experience. available Unit JmtlCCUnc~ . .c O ohm. L. The grid resistors and grid capacitors of each triode produce a negative d,c. As a member of IBM's development team, you will be working under the bias in the same manner as in Fig. 1. best possible conditions with the finest The feedhack capacitor of each triode equipment. You will receive ext.:ellent Technical electronic "Know-how" employee benefits and oPllortunities forms a voltage divider in conjun!'tiou for advanced education. Y:lU will be put to practical use in various living in a gro wing community r ~ cog ­ with the grid capacitor. Voltage divider ni-zed for its histcrical, cultural and action lilllits the amount of fepdback to scenic values. For further information, types of dynamic microphones. please reply full particulars to: the grid, preventing the tubes from be­ ing driven excessively. In Fig. 4, the Mr. A. J. Ronvaux, DYNAMIC MICROPHONE .01-1-' grid capac-ito!" has a reactance mnch Manager Professional Employment WITH VU METER smaller than 2~,OOO ohms at the bias IBM Corporation, Dept. 724B for Recording-level frequency, roughly 50,000 cps, so that Lexington, Kentucky monitoring the voltage divider consiRts principally ; . of the feedback and grid capacitors. Sometimes, to supplement the d. c. bias DM-194 ohtained by grid-Ipak action, cathode DYNAMIC MICROPHONE hias is also u~ed. That is, instead of con­ IBM(!) WITH TELEPHONE COIL necting the cathodes of the triodes di­ INTERNATIONAL BUSINESS rectly to ground, they are both connected MACHINES CORPORATION for Transistor Tape to ground thl'ough a common resistor Recorder & Office with a valu e of several hundred or a few use recorder_ thousand ohms. IE Uim('nsions: 56m / m ( h("ight )x 40m/ m ( width )X 20m/ m t thickn ess) SAVE YOUR DM-173-T HIGH EFFICIENCY TAPE COPIES OF WITH IMPEDANCE SWITCH TAPE NOISE SYSTEM DYNAMIC (f1'om page 26) MICROPHONE this value, it will be "masked" by the AUDIO Sprdfimlio ... room noise and will not he heard . f" U

82 AUDIO • FEBRUARY, 1961 measuring octave band program readings of 95 db by low frequencies. Usually an un­ in an ordinary li ving room-a level used weighted and a weighted value are giv!'n, mainly to impress friends with the and this might be a useful conerpt for height of the ]<-'i. The one called Normal tape reproducers. In the case of the re· (3) represents a reproducing level 15 suits just preRentl'd, for exalilple, and db lower, which is more representative using the A w(,ighting scale of a stan,l­ of a usual domestic listening intl·nsity. ard sound level meter, the signal-to­ What stands out· is the fact that the noise ratios measured were shape of the noise curve from the repro­ Unweighted, C-Scale 53 db (as given duction matches the shape of the back­ ahove) ground noise with which it competes. Weighted, A-Scale 74 db At the High setting noise is audible at both high and low frequencies to about These two numhers show that the most the same degree during eompletely quiet intense noise cOl1lponents are at low fre­ intervals of program. At the Normal quenci!'S where more can be tolerated, setting the reproduced nois!' would not while the high-frequency contribution is be audible in this "typical" room, al­ a great deal lower. If only the un­ though it might be in very qui!'t rooms. weighted number is given, a recorder But, even in a completely quiet room, with poor tape or poor construction Decorate your home with ... the shape of the reprotiuc-ed noise curve could measure n!'arly as well, yet give would remain satisfaetory, because the prohibitively annoying high-frequency Living Music actual minimum sensitivity of hearing noise. Thus by adding one additional qlLlHHlneL HI-FI nearly parallels the room noise curve. number, obtained with a relatively sim­ ple addition to standard mrasuring The versatility and beauty of Weighted Signal.to-Noise Ratio equipment, a great dpal of meaning Grommes Hi-Fi Equipment makes it possible for you to place it into The effects descrihed above are recog­ could be added to signal-to-noise ratio any mode of modern living. Whether nized in cOlllmunication alld noise meas­ specifications. In the critical li sten ill~ you prefer bookshelf, built-in or urelllent, where frequency "weighting" region good tape recorders give, not the cabinetry, Grommes Equipment of the response of the ml'asuring instru­ 50 db ordinarily thought of, but 70 dh blends into any interior decor. ment is used to reduce the contribution and more. IE 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 24) to demonstrate Grommes Equip­ (from page ment. You have a surprise in store for you! x K From mechanics the general expression (18) for the quadratic response to an input, y S2 3/\ -+- S + 1 y, is: of~ ill

DIVISION OF PRECISION ElECTRONICS. INC . 9101 King Avenue. Franklin Park. illinOIS

Fig. 11. Complete .: Dept. TJ : • Send coupon today for complete details on Grommes : analog of a quad­ : equipment • ratic response. · . : Name ...... • _...... •...... : ·: Street ...... •...... ·.: ·••.••....••.•••...... •...... •: City ...... Zone . ... State ...... : AUDIO • FEBRUARY, 1961 83 NEW! "the best of AU 0 10" No. 124 No. 120 A new compendium of AU.Dla knowledge. THE 4th AUDIO ANTHOLOGY Here is a collection of' the best of AUDIO-The AUDIOc1inic - $2.95 Postpaid by Joseph Giovanelli ... noted audio engineer and the original high fidelity answer-man-EQUIPMENT PROFILES edited by This is the biggest Audio Anthology ever! C. G. McProud ... Editor of AUDIO. Here is a wealth of hi-fi Contains a wealth of essential high fidelity and audio information. Answers to the most important issues in high fidelity and a valuable reference on the performance of know-how in 144 pages of complete arti­ leading makes of high fidelity components. Volume I $2.00 . cles by world-famous authors. 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 cov­ erage of every phase of audio. Concise, accurate explanations of all audio and hi fi subjects. More than 7 years in prepara­ tion-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 No.112 McPROUD HIGH FIDElITY OMNIBOOK TAPE RECORDERS AND TAPE RECORDING Prepared and edited by C . G. McProud, by Harold D. Weiler publisher of Audio and noted authority A complete book on home recording by the author of and pioneer in the field of high fidelity. Contains a wealth of ideas, how to's, High Fidelity Simplified. Easy to read and learn the what to's .and when to's, written so techniques required for professional results with home plainly that both engineer and layman recorders. Covers room acoustics, microphone tech­ can appreciate its valuable context. niques, sound effects, editing and splicing, etc. Invahi­ Covers planning, problems with decora­ able to recording enthusiasts. Hard Cover $3.95. Paper tion, cabinets and building hi-fi furni­ Cover $2.95 Postpaid. ture. A perfect guide. $2.50 Postpaid.

Save over 50% with this collection of AUDIO books. by Edgar M. Villchur FEBRUARY 4th Audio Anthology ($2,95) McProud High Fidelity Right up to date, a complete course on Omnibook ($2.50) best of AUDIO ($2:00) Tape sound reproduction. Covers everything Recorders '& "Tape Recording ($2.95) from the basic elements to individual SPECIAL! chapters of each of the important TOTAL VALUE OF ALL FOUR BOOKS $10.40 components of a high fidelity system. Regularly $6.50 ... offered for ·a limited SAVE Your cost ONLY $5.00 POSTPAID time at only $3.75. This offer expires February 28, 1961 SPECIAl! You pay only .$2.75 for this $5.40 Good only on direct order to Publisher CIRCLE 05102 book when you order it w.ith any other

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: 1-10 112 115 120 123 124 05102

NAM~E ______ADDRESS, ______

CITY______ZONL-STAT~E ______--' where ~~ Eavesdropper sensitivity K=gain plus Earwitness fidelity OJ = natural frequency make AKG's D 24 B dynamic mike 6 = damping ratio from Vienna a must for every By comparing (17) and (18) it is seen tape-recordist with a sense of that: values - for everyone who knows the True Sound of Music! S Wide, flat response: OJ= M (19) ~ high sensitivity: strong cardioid pattern: Kd~ (20) bass-cut switch - 200 Ohms. 6=2 K sM Imported and serviced in USA by Electronic Applications, Inc. 1 K=- (21) Stamford, Connecticut. Kg In order to show how an analog cir­ · mi.~t is constructed, equation (16) is em­ ployed. Solving for the S2X term equation 16 becomes:

_ S2X = K(] Sx + K 8 X _ F ( S) (22) M M M 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 ". t'{ ., . ~' . obtained. . " o _ Kd Kg kr - k" S-ex - M kx Sex + M k" ex - M et (23) Constants such as Kd, M, and Kg are Garrard Div., British Industries Corp.,Port Washingto n, N. Y. not scaled as they will appear as fixed Circle 858 gains. It is also seen that the scale factor kx is independent except relative to kf since it cancels in all the ex terms. ADVANCE ORDERS Assume that the voltages on the right hand side (Se", ex, et) of equation 23 BOUND VOLUMES are available in the simulation. These are then added in an adder amplifier through 1960 Issues gains proportional to the coefficients Audio Magazine Kd K. kf) . ( M' M' kxM . ThIS is shown at am- plifier 1 of the basic analog circuit shown Order Now* in Fig. 11. The output of amplifier 1 is + S2exo Amplifiers 2, 3, 4, and 5 are LIMITED NUMBER straightforward integrations and sign AVAILABLE inversions to find Sex and finally ex it­ self. By using these signals as "feed­ backs" to amplifier 1 with the proper $10.00 EACH POSTPAID gain ratios as indicated, a complete U. S. DELIVERY ONLY analog of equation 22 is found. Since equation 22 is equivalent to equation 18, this is also . an analog of equation Send Order 18; the quadratic response. and Rem ittance Today The main characteristics of the quad­ ratic are the frequency ' and damping. These quantities are seen to be deter­ Book Division mined in the analog by the gains into amplifier 1. Radio Magazines, Inc. Variations in these gains are analogs of variations of frequency and damping P.O. Box 629 of the system described ' by equation Mineola, N. Y. 22. Optimum , values can be quickly determined and translated back to the actual system parameters. " Delive ry J a nuary 16, 1961 The general use of the quadratic re­ sponse has been described because it is Circle 85A

AU DIO • FEBR UARY, 1961 85 the most common expression III audio work. :--CL}\SSIFIED~ In the tone arm-cartridge combina­ tion, for example, this expression ap­ Rates: lOc per word per Insertion for nonenmmflrelal .tdvertl~t!mflnb: 25C: pllr word for commflrelal .dur. PPal'S three til li es. The spring of the tluments, Rates are net. and no dllcolnb will ,. ~tylus, the llJass of the arm and cart­ ,Jlo.ed, Copy mad be Iccompanhld by r.mlttance In '.11. and mud " •• h Ih. No. York ofll.. by tb. ri;lge, anu the dailiping of the pivots ftrsl 0' the month pre •• dlng tbe date of I ..... for'm one resonant quadratic system. The ~pring of the stylus, the llJaRS of the HIGH FTnI·;UTY ~1'E.\ KEn~ R E1'.\ mED stylm;, and the dumping of the signal AlIll ' HI'l'E ~1'EAKEH I'IW\' I CE pick-off forlll the second. The spring of 168 W. 23rd :St., X,.w YOI'k 11, N. Y. CH 3-!812 the rpcord vinyl lJlaterial, the mass of EXJOY I'LEAS.\XT ~I'RPRT~E~? '1'11<'11 the stylus assl'llIhly, and the pick-off WI'itf? u~ before you IHII'("hnxe nny h :-ft, Yuu'll ullmpin~ provide the thir'd, be glad YUIl ,1 it!. Ilnu,na I ,a ving'. !i:Py Eh'c­ trunic', I:.!O Liberty Ht., New York G, ~. Y. The ~peaker system contains a quad­ CLo\·PI·,la Ie 8-~ :!88. ratic rpsponse with the mass of the cone, "'RITE fur ('unfi

86 AUDIO • FEBRUARY, 1961 there is mequal to ~ '.AJfjQ~ : SHURE. WESTMINSTER PRODUCE ...... STEREO RECORD. An unuRual1y illt<' r­ From time to time, a component has ANTENNAE' . ,. e:-otlng ap]l"'JH('h to 111er('handising CClr­ trldges ane1 tone arms iR the stereo reco"d appeared on the market which was \las THE FINEST OF ITS KIND ••• commiRRionl'd by Shure Brothers. Inc. good as Marantz". Fortunately for our The recording. "The Or(,hestra . .. The Get more FM stations with the world's most Instruments," No. LS66l. hy 'VestminRter morale., subsequent investigation has powerful fM Yagi Antenna systems. R e cording Co. iR not for sa Ie hut is avail­ always proved our position secure, and ahle at no c:harge to huyers of S hure car­ To be fully informed. tridges or tone arms. A('('('rning to Shure. strengthened our reputation for making this record offers an pxcel1ent test of a the finest custom preamplifiers and am· send 30~ for book steren RYRtem'R c-npahilitieR. "Theme And Varia· plifiers in the world. We invite you to tions" by L. F B. Carini ROBERTS BUILDING NEW PLAN'l'. compare the performance of other makes ""llh l ape ,·e",,,,d ... ,· "" Ie " ~R per ('ent ahead and containing FM of p!,ojections for the y ear, noberts E:l ec­ with Marantz characteristics described trollies h aR hepn forc-ed to expand fa­ below: Station Directory. cilltieR. The new 50.000-"'Iuarp-foot plant which will bl' locat<>d at 5nlR Bowcroft Ave., L os Angeles, Is scheduled for com­ • MOST DEPENDABILITY Repairs are so rare APPARATUS DEYnOPMENT CO. pletion on the lRt of March. WETHEISFIELD t, CONN thaI MorOnlZ devotes less thon 8 mon-hours per weeA ACRO CHANGES NAME. Acro Products to service. Compore I Circle 87C COlllp.ilny 11 :1:-; finally ("lIlltirmpd a f a ct ' v e have Rt"ongly su"pected theHe many years -t h ey a,'e in t loe e lectronic R bUf;iness. Frllm nnw on thpy'l1 he kno,vn ns the CANADA Aoro Electronic Products Company. In Hig h Fidelity Equipment k.,eping with thi" e'hange Le ona "d Klings­ Model 7 Complete Lines • Complete Service berg has been appoin , pd Executive Vice President and memher of the Board of Stereo Console Hi-Fi Records - Components DiI·l'ctors. A 1"0 \Villiam F. Carter has and Acces.ories been appointed aRf;i,.,tant to Chief Engineer (alld Pr.·,..irt,.nt) Hp"hr'rt r. KerneR. • LOWEST DISTORTION I.M. Di slorlion @ 10 v. equiv. pk. RMS . . . ma ximum permissible,_ STROMBERG-CARLSON APPOINTS 0.150/0. typical. - 0. 10/0' Reduces 10 a lew hun­ v. P. C iellrge J. Di(,'k~y. uf PI'inl'cIOn, ~ .•J., BLECTRO~UOlCE haR been app"inlf'd vice preslrlent and dredths 01 10/0 below about 5 volts output. Dislor. a""istant gene"a l manager of the Strom­ lion does ~ increase significanlly at frequency SOUND SYSTEMS berg-Cad,.,on f);"i,..illn of General Dy­ extremes. 126 DUNDAS ST. WEST. TORONTO. CANADA n am ics Corp. IIII'. ni"key come" from the cOl"l)oration's headquHl' t ers office in New • LOWEST HUM & NOISE Equivalent loral Circle 87D York, v.. hel'e h .. w a s a~~i:..;tant to Execu­ noise input, 20-20,OCIO cps •.. J microvoll max., 0.8 tive Vicp. f'residpllt C. nh",.,des :llacBride. microvolt typical (SO db below 10 millivolts inputJ. A native of :\'ew York f:'i l y , :If,'. Dicl'ey 'waR pduf'ated in the RidgpWf,nd. N. J. puhlic 8t'honls and at N'))' I h eaHlern Uni­ • HIGHEST GAIN AI 1000 cps, RIAA equoliza. ELECTROSTATIC TWEETER vel·sity. R~flll'e joining (jenera) Dynanl i cs lion.- 0.4 mil/ivol/s. 1400 microvolts/) for I voll in :I'l a r ch 191iO, III" . Di"key work"d for output. THRILLINC John W . Stok"s Cn. of B,,:-:ton. and John­ HI FREQUENCY son & Johnson in New Brm,wick, N. J. • FINEST CONSTRUCTION In strumenHype. precision construction throughout. Basic circuit on RESPONSE heavy, fully shock-mounted turret-terminal boord. ONLY $19.95 Wiring neally cabled. Noise-selected Htm resistors. if you are about to buy a tape recorder­ Power transformer double-shielded with mu-metal ORDER BY before " potting". Trjple-fillered D.C. l i/ament sup­ MAIL YOU CAN SAVE MONEY! ply. Fully fjnish ed chassis. Front panel. Va" thick­ if you own a tape recorder- ness brushed aluminum. pale gold anodyzed. with precision-machined matching knobs. • ENJOY BETTER PERFORMANCE! • GREATEST ACCURACY Equalizolion and ton~ GETTING THE MOST OUT OF YOUR conlrol curves matched ;n both channels to 0.5 db. cna.iJ.rm~i.'~;:~;' TAPE RECORDER - I ypical, 0.2 db. by H er'/'lUl,n Burstein Herman Burstein. noted high fidelity author­ Circle 87E ity. 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 HEADS YOU WIN! to these questions: You' ll be a winner by sov­ ing "heap plenty" on your • What features are necessary or desirable in Hi-Fi needs. Write todayl a tape recorder? • 30 WAns RMS, per channel Iconservalively Ask too for discount cata­ • What can I do to get the best performance raled! ±0.2 db 20·20,000 cps. log A-12. out of a given tape recorder? • How to select the best tape recorder for the money and your I'! HIGHEST STABILITY Will nol oscillal~ under KEY ELECTRONICS CO. needs? • Special questions and problems any condition, with or without load. Completely 120 liberty St., N.Y. 6, N.Y. raised by stereo. #251, $4.25 stable to capacitive loading. Instantaneous re cov­ FUNDAMENTALS OF HIGH FIDELITY by Herman ery (rom major overloads prevents breakup noticed Circle 87F Burstein. How to select the best hi-fi equip­ in other circuit designs. ment for the money you have to spend-how to achieve the best performance and realize • LOWEST HUM & NOISE Be ller thon 90 db the most pleasure from your equipment. #226. below 30 watts, open circuit, with inpu·,. typically. PACKAGE HI FI $2,95 beller Ihan 100 db below 30 walls. or SINGLE COMPONENTS STEREOPHONIC SOUND by Norman H. Crow­ hurst. Saves you hundreds of dollars in.$elect­ • FINEST CONSTRUCTION Sprague type 17D You'll find our prices low ing your stereo system. #209. $2.25 ·telephone-quality electrolytics. Epoxy-encopsulated and service fast . mylar coupling condensers. Silicon rectifiers. Cabled Write for our quotation REPAIRING HI-FI SYSTEMS by David Fidelman. Save money! Deals with finding and repairing wiring. Metered bios and signal-balance adjustments. Center Industrial Electronics, Inc. the troubles. #205, $3.90 74-A Cortlandt St. New York 7, N. Y • MOST CONSERVATIVE El34 ourput tubes HI-FI LOUDSPEAKERS & ENCLOSURES by Abra­ operate coolly, 01 only 50 ma plate current. ham B. Cohen. Answers all questions on loud­ Circle 87C speakers and enclosures, design, crossover net­ works. etc., #176 Marco cover• . $4.60; #176-H • LOWEST DISTORTION AI 30 walls, less than cloth bound, $5.50 0.10/0 harmonic distortion @ J kc. less IhO;;-O .3% @ 20 cps. I.M., ~ than 0.5%. - A NOTE TO THE HI-FI BUYER GUIDE TO AUDIO REPRODUCTION by David AIR MAil us your requirements for Fidelman, Covers design, assembly and testing of sound reproduction systems and compo­ The cost? Necessarily a little more ... but an IMMEDIATE WHOLESALE QUOTATION nents. #148, $3,50 Components, Topes and Recorders well worth it. Write for booklet 41 P. SHIPPED PROMPTlY AT LOWEST PRICES at bookstores. or ordn rliTut.' Drpt. A-2 WRITE TODAY FOR FREE CATALOG ·_"'UCES SUOJECT TO CHANGE WITHOUT NOTICE a u d i 0 190-A lexington Ave. - I JOHN F. RIDER PUBLISHER. INC. unlimited New York 16. N. Y. 116 W. 14th St.. New York 11. N. Y. 25-14 Broadway, Long Island City 6, N. Y. ,

Circle 87H Circle 878 Circle 87A

AUDIO • FEBRUARY, 19'61 87 ADVERTISING INDEX • Acoustic Research, Inc...... •...... 37 LA-600A Completely Wired Allied Radio Corp ...... 77, 86 KT -600A In Kit Form Altec Lansing Corporation ...... 10, 39 Amperex Electronic Corp...... 76 79.50 134.50 Ampex Audio Company ...... 30, 31 S.OO Ampex Professional Products Company .. 45 DOWN ~' Apparatus Development Co...... 87 • Response 5·40.000 cps ± 1 db. Audio Bookshelf ...... 84 • Precise "Null" Balancing System Audio Devices, Inc...... • .. . . . 55 • Unique Stereo and Monaural Control Features Audio Dynamics Corporation ...... 1 1 • Concentric Input level Controls Audio Empire ...... 49 • Easy·lo·Assemble Kit Form. Audio Fidelity Records ...... 61 Audio Unlimited ...... 87 Sensml',t~ 2.2 mv for 1 volt oul. Dual low impedance "plate follower" outputs 150Q ohms. less than .03% Belden ...... • . . . . .•...... • 5 1M distortion; less than .1 % haqnonic distortion. Hum Bel Canto, A Subsidiary of Thompson and noise 80 db below 2 volts. 14xlQ!Vax41f2". Sh·pg. Ramo Wooldridge. Inc...... , .. ... 33 wt., 16 Ibs. Made in U.S.A. Bogen- Presto, A Division of the Siegler Corp...... :...... 53 E REMARKABLE KT-6S0 FM TUNER KIT British I ndustries Corporation •...... 3, 85 Center Industrial Electronics, Inc...... 87 LT -6S0A Completely W Classified ...... 86 KT-650Kit 54.50 79.95 Crosby Electronics, Inc...... 71 Down • Virtually Distortionless Performance-less EICO ...... 13 s.oo Than .15% Distortion at 100% Modulation El ectronic Applications, Inc...... 85 • Sensitivity 3 flV for 30db of Quieting Electro-Sonic Laboratories, Inc...... 59 Electro-Voice, Inc...... 25 • Response ± V2db 15·35,000 cps Electro-Voice Sound Systems, Inc...... 87 • Variable AFC Professional FM laboratory Standard Perform· Fisher Rad io Corporation ...... 9 anc,e - _ Ci~c~itry_ .. e.'Ppl~Ys .a low noise front Fukuin Electric (Pioneer) •...... '. 47 end with ' tnode ' mixer plus double tuned dual I im iter and wide band Foster Seeley discrim· Garrard Sales Corp...... 3 inator. IF and Discriminator coils are factory Gotham Audio Corporation .... . • .... . 80 prealigned-permits playing ! he tu~er ~s soon Grado Laboratories, Inc...... 72 as assembly is completed . Pnnted CIrCUit board Grommes, Division of Precision and famous lafayette instruction manuals make Electronics, Inc...... •.... 83 Made in U.S.A. kit building a pleasure. 14x%Hxll"D. Shpg. wt., 13'12 ·Ibs. Harman-Kardon ...... 43

T-5S0 lO.O-WATT BASIC STEREO AMPLIFIER K I nternational Business Machines Corporation ...... 82 KT-SSO In LA-SSO Completely Wired Kit Form 134.50 Jensen Manufacturing Company ...... 41 S.OO Down Key Electronics Co...... 87 Kierulff Sound Corporation ...... 87 • Rated at 50-Watts per Channel KLH Research (,0 Development Corporation 70 • Response from 2·100,000 cps, 0, ·1 db at 1·Watt Klipsch and Associates , ...... 86 • Grain Oriented, Silicon Steel lransformers • Multiple Feedback loop Design Lafayette Radio ...... 88 • Easy-lo·Assemble Kit Form Langevin, a Division of Sonotec A new "laboratory Standard" dual 50-watt amplifier Incorporated ...... 14 guaranteed to outperform any basic stereo amplifier Lansing, James B., Sound, Inc...... 57 on the market. Advanced engineering techniques plus the finest components ensure flawless performance. Marantz ...... 87 Distortion levels so low they are unmeasurable. Hum Movic Company, Inc ...... •. . . 78 and noise better than 90 db below 50-watts. Complete with metal enclosure. 91/4 X12lf2 " D. Shpg. wI., 60 Ibs. Neat Onkyo Denki Co., Ltd...... 2 North American Philips Co., Inc. • ...... 15

-SOO,A FM- STEREO TUNER KIT Peerless Electrical Products, A Division of ~---~. Altec Lansing Corporation ...... 10 L T -50A Completely Wired Pickering (,0 Company, Inc...... 17 KT -500A In Kit Form 74.50 Pilot Radio Corporation ...... •. .... 7 Primo Company, Ltd. • ...... 82 Down 124.50 RCA Electron Tube Division ...... Cov. II • Multiplex Output. for New Stereo FM Radio Shack Corporation ...... 63 • Armstrong Circuit with Dual limiters and Foster· Rek-O-Kut Company, Inc. .. . .•...... 81 Seeley Discriminator Rider, John F., Publisher, Inc...... 87 • Extreme Sensitivity and Wide Frequency Response Roberts Electronics, Inc. •...... •.. 62 • Easy-la-Assemble Kit Form Rockbar Corporation • ...... 27 Separate FM and AM tuning sections, each with its magic eye. FM: automatic frequency control, 2 micro' Sansui Electric Co .• Ltd...... 78 volts sensitivity for 30 db quieting, frequency response Sarkes Tarzian, Inc . •...... 79 20-20,000 cps ±!h db , full 200 kc band width. AM: Schober Organ Corp...... 6 efficient broadband cirCUitry, built-in antenna. Two Scott, H. H., Inc ...... 75 printed circuit boards make wiring simple. 13¥4 XlOY.x Scott Radio Laboratories. Inc...... 51 4'12". Shpg. wI., 22 Ibs. Sherwood Electronic Laboratories, Inc. .. 1 ,Shure Brothers, Inc...... 69 ' Sonotone Corp...... • 4 Superscope, Inc...... 35

Tandberg of America, Inc...... 73 Transis-Tronics, Inc ...... Cov. IV Lafayette Dept,' AB-1 P.O. Box 190, Jamaica 31, N. Y. Tung-Sol Electric Inc...... 65 Name ______. ______"______United Stereo Tapes ...... 66 Address ------.------University Loudspeakers, Inc...... 67 City ______Zone ______State______Viking of Minneapolis ...... Cov. III G.... .A.F.A. "Y'ETTE ------NEWYORK .13,N.Y. BRONX 58, N.Y. NEWARK 2, N.J. Weathers I ndustries, A Division of aJL... :R..A.:J> X <> I Advances I ndustries, Inc...... • 64 LOCATIONS JAMAICA NEW YORK PLAI , N.J. PARAMUS, N.J. BOSTON 10, MASS

88 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 heavy­ duty 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.

'<---+-I-'I...... ,.:3IL{I" , ng OF MINNEAPOLIS, INC . The Viking Stereo "Super-Pro" , Half·track or quarter·track recording models. 'rl----1I-t--t-+z' 9600 Aldrich Avenue South, Minneapolis 20. Minnesota Audiophile net $344.50 to $379.50 depend­ ing on head complem 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, . ·power; balance; bass channel A; bass channel B; treble

channel A; treble channel 8; function (phono, tuner, tape, ' aUXiliary I, auxiliary 2); mode (mono A, stereo, mono B); loudness; scratch filter, rumble filter. Balance Control for TE • C , equalizing speaker outputs. At full rotation will completely cut off sound from either speaker. Circuitry, 2 germanium -...'1 :5' . diodes, 3 silicon diodes. Power Requirements 105-120 volts AC, 50-60 cps; 12-28 volts DC for battery operation. S TEC Transistor Engineered Components I e I

--.J''______f..;:, EC;,..;.;." ....fH..;:, E.... ' ..... AO..;:,.. EMA.K 0' f.A"'''·'.O"'C,. '"c . Trallsis-Tronics, Inc., 1601 Olympic Boulevar~, S~ nta Monica , California