47425 le" THE AUTHORITATIVE MAGAZINE ABOUT HIGH FIDELITY NOVEMBER 1976 $1.00 Build the Latest CD -4 Demodulato Four -Channel Radio Syndication AmericanRadioHistory.Com Pi( niter HPM-200 5-su - 5-driver system n( (1 11P'1-6() -3.zn 1 -(Iriwr s stem Pioneer HPM-40 3 -way 3 -driver system AmericanRadioHistory.Com The HPM series. Four radically new speaker systems specifically designed to beat the best. You can't beat JBL, Advent, of price, the top end of the audio Bose and AR with me -too ideas. spectrum is reproduced by an They're really good speakers. HPM driver. In the big HPM-200 So, instead of just trying to make system, so is the upper midrange. better conventional speakers, we The woofers used in the HPM knew we had to come up with a series are almost as unconventional, totally different and superior design even though they still have cones. concept. But what cones! They combine low After years of research and mass and high rigidity to an development, our engineers found unprecedented degree, thanks to an the answer. They created a whole exclusive method of reinforcement new technology based on the with carbon fibers. As a result,they electrical properties of High move as true pistons, without any of Polymer Molecular film. The result the smearing of bass frequencies is a sound that's louder, clearer, more experienced with ordinary cones. natural, lower in distortion than you Of course, the proof of a new ever expected to hear out of a speaker technology isn't in the telling speaker system. but in the listening. HPM film technology requires If the new HPM speakers didn't no magnet, no coil, no cone or dome, have audibly more impact, more no moving parts at all. The detail, more transparency than the amplified signal is converted into best previous speakers at compa- sound waves directly at the surface rable prices, our engineering effort of a thin, light membrane. And the would have been a meaningless entire structure housing the exercise. There are certainly enough membrane can be curved for the speakers on the market today. best possible sound dispersion. So we invite you to listen and Pioneer's new HPM drivers compare very carefully. Match the combine high efficiency with HPM in the price range of your amazingly accurate transient choice against the corresponding response. Distortion is virtually speaker on the far right, or anything nonexistent even at very high sound - else in your dealer§ showroom. pressure levels. The principle was We think you'll end up agreeing evolved mainly for tweeters, that a good new idea beats a good although a giant HPM woofer is at old idea every time. least a theoretical possibility. U.S. Pioneer Electronics Corp., In each of the new Pioneer 75 Oxford Drive, Moonachie, models shown here, regardless New Jersey 07074. AmericanRadioHistory.Com It would be foolish to create a new line of speakers and not overcome these obstacles... AmericanRadioHistory.Com vent Loudspeaker ose 901 Serie; Il Check No. 36 on Reade- £ervice Card ®h,5, PIO,PER FIECTRONIC'. CORP ,1979. AmericanRadioHistory.Com You Can't Do Better November 1976 "Successor to RAD1Q Est. 1917" Vol. 60, No. 11 ForTwice Feature 26 Christmas Buying Guide 36 Build the Latest CD -4 Demodulator/Joseph Giovenco Articles 46 Syndication of Quadraphonic Radio Programs/ The Price Martin Clifford Equipment 52 Sonab C-500 Cassette Deck/George Tillett Spectro Acoustics 210 Equalizer/Len Feldman Profiles 60 McIntosh C-28 Preamplifier/Len Feldman 74 Yamaha HP -1 Headphones/C.G. McProud STAX SR-44-Incomparable fre- 76 Heath AA -1640 Amplifier/Bascom H. King quency response, efficiency and 84 Dynaco A-25XL Loudspeaker/Richard C. Heyser transient rise time for $35. Work Bench 89 White 140 Analyzer/Howard A. Roberson Crown M-600 Amplifier/Ed Goldman Profiles 92 Record 94 The Column/Michael Tearson & Jon Tiven 103 ThClaseatercal Muwarsic/DdonaldTatnallM. Reviews 108 /Ed C anSpotobysi 111 Canby's Capsules/Edward Tatnall Canby 112 Jazz & Blues/John Lissner & Eric Henry 117 The Folk Bag/Tom Bingham Audio 4 Audioclinic/Joseph Giovanelli Audio ETC/Edward Tatnall Canby In General 16 Behind The Scenes/Bert Whyte 24 Dear Editor 30 Tape Guide/Herman Burstein 98 Advertising Index 123 Classified Advertising Editor Eugene Pitts III AUDIO (title registered U.S. Pat. Off.) is published Associate Editors monthly by North American Publishing Co., Irvin J. Borowsky, President; Frank Nemeyer, and Jay L. Edward Tatnall Canby Butler, Vice Presidents; R. Kenneth Baxter, Vice Bert Whyte President/Production; Vic Brody, Promotion Direc- tor; Mary Claffey, Circulation Director. Assistant Editor Eugene J. Garvin Jr. RATES-United States only: 1 year for $7.00, 2 years Marketing Director Sanford L. Cahn for $12.00; 3 years for $17.00; outside the U.S.: 1 year Design Frank Moore for $9.00, 2 years for $16.00, and 3 years for $23.00. Circulation Manager Jean Davis Printed in U.S.A. at Columbus, Ohio. Ali rights Advertising Production Gloria Klaiman reserved. Entire contents copyrighted 1976 by North American Publishing Co. Second class postage paid Senior Editors at Philadelphia, Pa. and additional mailing office. Back issues, $2.00 each. World Library Congress Richard C. Heyser Number: ISSN 0004-752X. Dewey Decimal Number: Bascom H. King 621.381 or 778.5. B.V. Pisha REGIONAL SALES OFFICES: Jay L. Butler, Publisher and Sanford L. Cahn, Marketing Director, 545 Madi- Contributing Editors: son Ave., New York, N.Y. 10022, telephone (212) 371- 4100. Tom Bingham, Herman Burstein, Jay Martin, 2525 West 8th St., Los Angeles, California Leonard Feldman, Joseph Giovanelli, 90057, telephone (213) 385-2917. C.G. McProud, Dan Morgenstern, REPRESENTATIVES: Europe, V. B. Sanders, Interna- Howard A. Roberson, Donald M. Spoto, tional Publishers Advertising Service, Raadhuisstraat 24, P.O. Box 25, Graft-de-Ryp, Holland; telephone, Michael Tearson, George W. Tillet, 02997-1303; telegrams, Euradteam-Amsterdam. Jon Tiven. Japan: Japan Printing News Co., Ltd., No. 13.2 Chome Ginza Higasi, Chuo-ku, Tokyo, telephone Publisher Jay L. Butler 541-5795. EAHSKANEM 41D-4 STAX ADAP1aa Ea Et ECTEIET 5 v AME4 2 C About the cover: Here is our artist's view of psychocybernetic quadra- yNG phony. The necessary printed circuit AUDIO Editorial and Publishing Offices, boards and knobs are mounted in 401 No. Broad St., Philadelphia, Pa. 19108 mannequin heads. Then for a better Postmaster: Send Form 3579 to the above address. high range, loudspeaker tweeters were also mounted in the heads for a sound conversation piece in your home. WIAmerican Audioport Columbia, Mo. 65201 AmericanRadioHistory.Com Stanton Stereo Wafers M The livest sound,the highest fidelity ...plus the livest look. Looks Just Great... ...Any WayYou Look At It! Hail to a totally new concept and technology in head- are also of much smaller size, while still allowing Stanton to phones. And hail to an Open Audio design that gives you the achieve an improved response over headphones incorporat- lightest weight comfort you've ever experienced with head- ing conventional permanent magnets. phones that possess truly top quality sound. The soft foam cushioned headband is exceptionally com- These ultra thin headphones have been designed and en- fortable and has a trendy brushed denim fabric covering. The gineered to meet important professional needs: extreme com- earpiece yokes incorporate specially designed pivots which fort over long listening periods, a particular wide frequency allow the earpieces to fit perfectly against the ear, whatever response, and a broad dynamic range. A major factor in the the shape of the head. success of the design is the use of rare earth elements in the Write us for the specs - they're magnificent! compound of the permanent magnets of each earpiece. Be- And ask for a demonstration as soon as possible sides having superior magnetic properties, these magnets at your Stanton dealer. Write today for further information to Stanton Magnetics, Inc., Terminal Drive, Plainview, N.Y. 11803. Check No. 35 on Reader Service Card AmericanRadioHistory.Com The Best Way To Show YouWhat You'll Get Joseph Giovanelli Out Of An Phono A.C. Adaptors constant. This is probably to your ad- Cartridge Q. Can the a.c. adaptors, such as vantage inasmuch as this kind of ser- O those sold for portable radios, calcu- vicing can be expensive. Where a lators and recorders be left plugged in problem occurs more or less con- ShowYou for long periods of time when they stantly, it is simpler to track down and, What Goes are not being used?-James R. Hen- therefore, less costly. derson, Victoria, B.C., Canada. You do know something about this Into One. A. It is only in those instances where problem, however. For instance, you the adaptor serves something like an know that the problem is not located stages of the At Empire we intercom, which must be ready for in the early phono make a complete line service at any time, that I recommend equipment. You know this because it of phono cartridges. these adaptors be left plugged in occurs even when these stages are Each one has slightly when not actually in use. switched out. It is located in stages different perform- These a.c. adaptors are actually common to the rest of the input func- ance characteristics complete power supplies and are tions. You did not state whether or which allow you to comprised of a stepdown transformer, not the condition exists in just one choose the cartridge If the condition exists in most compatible to a rectifier system, and the necessary channel. your turntable. filter capacitor. When one of these both, you know that the "popping" is There are, how- devices is operated, there is some the result of some common com- ever, certain advan- heat generated by the stepdown ponent, and power supply or de - tages, provided by transformer which will not be signifi- coupling elements would be suspect.