THE B.A.S. SPEAKER

EDITOR-IN-CHIEF: Brad Meyer Subscriptions & Membership Information COORDINATING EDITOR: Peter W. Mitchell THE BOSTON AUDIO SOCIETY P.O. BOX 7 STAFF: Robert Borden, Alvin Foster, John Schlafer, BOSTON, MASSACHUSETTS 02215 Jack Stevens VOLUME 8, NUMBER 10 PUBLISHER: Peter W. Mitchell, President, BAS JULY 1980

THE BOSTON AUDIO SOCIETY DOES NOT ENDORSE OR CRITICIZE PRODUCTS, DEALERS, OR SERVICES. OPINIONS EXPRESSED HEREIN REFLECT THE VIEWS OF THEIR AUTHORS AND ARE FOR THE INFORMA- TION OF THE MEMBERS. REPRODUCTION OF ANY PORTION OF THIS NEWSLETTER FOR ANY PURPOSE WHATSOEVER WITHOUT WRITTEN PERMISSION OF THE PUBLISHER IS STRICTLY PROHIBITED.

In This Issue In response to numerous requests this issue also includes comprehensive This issue is part of our big subscription information on most of the catch-up effort: the second of English-language audio publications three issues to go to press within which we abstract in the IN THE LIT about six weeks. Its contents in- column and recommend that you read. clude two BAS meeting reports, a double dose of IN THE LITERATURE, This issue is also an experiment and a collection of three reports in typography. We have occasionally on interesting things seen and heard wondered whether setting the SPEAKER at the Consumer Electronics Show in in double columns, rather than one June. long line of type running the full width of the page, would make it The regular June meeting featured easier to read. Let us know what Tony Federici of Scheiber Sonics you think. and an old Boston boy, Daniel Queen, with an interesting exploration of On the other hand, circumstances acoustics and imaging. A special dictated that this issue be produced bonus June meeting featured some on an IBM Selectric, whose letters guests from Japan: Mr. Naotake Hayashi, are aligned vertically as well as President of Stax, with some sweet- horizontally. This tends to make sounding equipment designs, and Mr. large blocks of type more difficult Saburou Egawa, reviewer and consultant, to read. So, whether single column with some startling ideas and pro- or double, we definitely intend to vocative demonstrations. Perhaps revert to our previous typeface (with the latter will provoke not only a proportional spacing of letters) in lot of discussion but also some in- the next issue. formative experiments.

The B.A.S. Speaker (ISSN 0195-0908) is published monthly by The Boston Audio Society, Trapelo Road, Lincoln, MA 01773. Subscriptions are available to members of the Society. Membership dues are $12 per year, October 1 through September 30 ($25 U.S. currency overseas, including air mail). $11.45 of the dues are a subscription to The B.A.S. Speaker including all issues of the applicable membership year. For further information and application form, write to The Boston Audio Society, P.O. Box 7, Kenmore Square Station, Boston, MA 02215. Second-class postage paid at Boston, MA. POSTMASTER: Send address changes to: The B.A.S. Speaker, P.O. Box 7, Boston, MA 02215.

Copyright ® 1980 The Boston Audio Society Vol. 8, Num. 10 July, 1980 The BAS Speaker OCRed from printed copy - errors possible. Used Equipment Broker The newsletter is to be published monthly and distributed nationally via first-class mail. Over the years my interest in audio The goal of the NEEE is to help has led to the purchase of used equip- develop a larger and more efficient ment from various sources. In the market for used audio equipment. Ad- Boston area the Phoenix, Want ADver- ditionally, readers of the newsletter tiser, and Boston Globe, as well as will be advised of industry news -- the odd poster nailed on neighborhood technical developments and business trees, all offer used audio equipment successes (or setbacks) that may affect for sale. As with any other aspiring the market value of audio equipment. local buyer I may respond to the ad, A subscription to the newletter will visit the seller, examine the item in be priced at $12.00. question, and may use anything from a The advice and experience of B.A.S. deft kick to a portable oscilloscope to members is urgently solicited, to make complete my notion of analysis of the this a useful service to the interested products condition. audiophile. Members are invited to call When the ad is in a national pub- or write for a free sample copy. lication (Audio, Audiomart, B.A.S. New England Electronics Exchange Speaker) rather than a local one, the Box 82, Harvard Square audiophile does not enjoy the same op- Cambridge MA 02138 portunity of inspection. Of course, a satisfactory transaction will instill 617/491-3000 (Sun-Thur , 6Sony Corporation. The be as described; if not he is free to patent was applied for on May 23. 1978 return the unit and his money will be and was granted by the U.S. Patent Office refunded in full by the Exchange. on Sept. 4, 1979.

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What is the invention described But as luck would have it, during in U.S. Patent 4,166,624? It is a the past year my work as consultant record player, described in the JASA has involved a number of tests of summary as follows --"a little bus prototype headphones for clients, so which scoots about the record using I have been exposed to a number of the groove for its tracks. The outer different headphone models of vary- rear wheel, 4b, is larger in diameter ing quality and type. And I have than the inner rear wheel, 4a, so developed a procedure for measuring that the little vehicle tends to move the frequency response of headphones in a circular path." The tiny van body which appears to correlate fairly contains a battery, drive circuitry well with the gross subjective dif- for the wheels, an amplifier, and a ferences I hear. ("Gross" is an ap- little speaker. Trailing the van, propriate word here, as the frequency and connected to it via a universal response aberrations and colorations joint, is a stubby tone arm, head- of many headphones from reputable shell, and cartridge. The illustra- manufacturers are indeed gross, far tion below is reproduced from Sonys larger than the response errors among patent. todays better loudspeakers. Response deviations of ± 10dB are common and ± 20 dB not unheard of.) The key to the measurement is a "coupler" which, while unorthodox in construction, mimics fairly well the acoustic absorption properties of the human head and provides a surface on which the headphone is mounted, plus a hole in which the microphone of the Ivie IE-30A spectrum analyzer is Do you suppose Sonys engineers installed to measure the headphones read Audio? The examiners at the U.S. output. (No attempt is made to re- Patent Office obviously dont, since produce in the coupler the convolu- I. Lirpa seems clearly to have estab- tions and cavities of the outer ear; lished prior art sufficient to invali- differences among headphones are so date the Sony patent, at least in part. large that such refinements are un- -- PWM necessary at this stage.) The accompanying graph presents the one-third-octave response of the Stax SR-Lambda earspeakers as measured via this coupler. As rioted above, the credibility of this coupler rests Stax Headphones: A User's Report mainly on the fact that I have found its measurements to correlate well with the subjective differences I The Stax components demonstrated have heard among tested phones, and at the special June BAS meeting were that is true in this case as well. brought to Boston from Chicago, where As the measurement suggests, the Stax they had been used as demonstrators SR-Lambda is a very smooth-sounding in the Stax room at the Consumer Elec- headphone -- easily the smoothest I tronics Show. After the meeting most have tested to date. It has a notably of the components were eventually for- warm tonal balance which is much more warded to New England dealers to serve "musical" than "hi-fi", and disc as store demonstrator samples. Two surface noise is not exaggerated in samples were not: Mr. Hayashi left these phones the way it is in many the set of Stax SR Lambda Earspeakers others. In fact, given the reality and the associated SRM 1 headphone that records nearly always have a amplifier for me as a gift. It was brighter tonal balance than what one an extraordinarily generous gift, far hears when sitting halfway back in outweighing whatever assistance I gave a concert hall, the tonal balance to Messrs. Hayashi and Egawa in con- of the SR-Lambda seems ideally cho- nection with their visit to Boston. sen for listening to recordings. So the Users Report which follows is With many records these headphones not a coldly objective assessment; it impart a musically realistic texture is too much tinged with delight for ( especially in woodwind and string that. tone) which I have previously heard

3 only in live music and in full-range Its not audio nirvana for $49.95; electrostatic speakers such as the the price is $270, not including the KLH Nine, Acoustat Three, and Stax headphone amplifier. Speaking of ELS-8x. that, the SRM-1 driver unit does a splendid job of driving the SR-Lambdas, The SR-Lambda also shares the and is very convenient to use since principal flaw of these loudspeakers: it operates from line-level signals its tonal balance, while musically (i.e. from the output of a tape deck, euphonic and extremely pleasing, is tuner, or preamp). Thus one can have not dead-on accurate. Thus it is not superb headphone sound without having as appropriate for analytical monitor- to carry a power amplifier around. ing of on-location tape recordings as One final note: while the excellent a brighter, more forward reproducer sound quality produced by the combi- would be. (Of course for on-location nation of SRM-1 and SR-Lambda was not monitoring one would want to have surprising, their ability to play loud acoustically-isolated closed-back was. In the past some electrostatic headphones anyway; the drivers in headphones have been noted for fine the SR-Lambda are mounted in an acous- sound but have been severaly limited tically semi-open cage which doesnt in attainable volume levels: not isolate the listener from ambient sound.) these. The combination plays louder, Incidentally, dont interpret the clean, than most dynamic headphones sloped high end in the graph as meaning I have tested. The SRM drives all that the sound is dull or lacking in models of Stax electrostatic phones. highs? it is not. The highs are all Postscript: As a bonus a sec- there -- smooth, sweet, finely-etched, ond curve has been added to the graph. rather than sizzling. At the opposite Sony is marketing a line of extremely end of the spectrum, the bass is full lightweight, very comfortable phones and rich, if you want a tight, crisp of which one model is supplied with bottom end, look for something with the Walkman (formerly Soundabout) leaner low-frequency response. shirt-pocket stereo cassette player. The essential virtue of these and Other manufacturers are also introdu- other electrostatic phones, of course, cing similar headphones and small stereo isnt revealed by the response curve cassette units, and I have had a chance but only by listening: the delicacy to listen to and measure a few. The and transparency of subtle details, the Sony MDR-3 is typical of the breed freedom from congestion in complex (notably in its bass response) and is passages, the total lack of listening smoother than some. Considering their fatigue, the precise rendering of mic- very low weight and their comfort, rophone perspectives, they are pretty good. But there are conventional phones at the same price ( $50 list) which sound better. -- PWM

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In The Literature AUDIO, June 1980 Video Scenes (p.20): Bert Whyte describes the Pioneer videodisc unit ABSOLUTE SOUND, Issue No. 18 and the anatomy of the discs. • Behind the Scenes (p.32): Whyte • Special Report -- The New Tubes (p. enthuses about Cerwin-Vega . 129): Qualified rave reviews of the • Understanding Tonearms (p.52): B Os Audio Research SP-6B preamp and D-79 chief whiz surveys basic issues in power amp, the Beveridge RM-1 preamp, arm design. and the Dennesen DM IV tube power • Reviews (p.76): NAD 7020 receiver amp. ( a rave review of both tuner and ampli- • Three New Speaker Systems (p.144); fier sections; phono preamp is excep- Includes a lengthy essay on stereo tionally quiet). Optonica RT-6905 imaging, containing some debatable cassette deck with microprocessor timer- assertions. Pyramid Metronome Three controller (.fine performance, good Dolby ( truncated bottom end, worlds best tracking, over 60 pushbuttons, price tweeter, imaging specific but not $1600). Fisher 6250 turntable (good). satisfying). Dayton-Wright XG-10 Sansui CA-F1 preamp (excellent perfor- electrostatic (much better than the mance, with one oddity: the phono S/N XG-8 , sounds superb from mid-bass up measures 2 dB better than the theoreti- to mid-treble, needs a separate cal limit). Fried Model Q speaker (no tweeter, imaging is flawed). Hybrid deep bass, otherwise pretty good). Impulse (dynamic woofer plus ribbon tweeter/midrange, sounds fabulously good from 100 Hz up, bass is over- AUDIO, July 1980 whelmingly strong and flabby, imaging is flawed). • Behind the Scenes (p.20): Assorted • Considerations (p.157): Phase activities at Dolby Labs. Linear 8000 turntable (made by Pio- • Letters (p.26): Curl, Otala, Jung, neer, mostly superb, excellent iso- and Leach announce general agreement lation, smooth straight-line arm on TIM. performance, but some flaws are iden- • Car Stereo Directory (p.28): Specs tified). PS Audio PS--III preamp and features list. ( phono module very good, line-level • Keep Your Car Stereo Safe (p.60): On module not so). Yamaha PX-2 turntable antitheft protection. (isolation not as good as the Phase/ • Reviews (p.68): JVC A-X9 integrated Pioneer, otherwise the Yamaha is an amplifier (_"super-A dynamic-bias circuit, outstanding SLT system). NAD 3020 expensive, extremely clean). Dynavector integrated amp (a knockout at its Karat/Diamond m.c. cartridge and DV-6A price, especially with difficult transformer (ruler-flat response, perfect speaker loads; in some areas such channel balance, excellent tracking, as imaging it beats. certain very great sound). Connoisseur BD-2A turn- costly audiophile components). Sat- table (_no--frills design, belt drive, terberg MW-2 woofer (_splendid for use good arm, excellent price/performance). with mini-speakers, ideal with the Rogers LS3/5A). • Further Thoughts (p.171): Linn AUDIO AMATEUR, 1980 No.3 Sondek vs Scardina-modified B 0 40Q4 SLT turntable (closely competitive). • Upgrading Your FM Tuner (p.7): How Cybele loudspeaker (smooth, distant to bring an old dinosaur into the modern age. sounding, best with Audionics CC-2 amps). • Installing FM and TV Antenna Sustems Stax CP-Y/ECP-1 cartridge (p.14): system (seriously flawed in frequency John Allens authoritative discussion makes its third appearance response, separation, and channel balance). in print. • • Technocracy (,p.176): Interview Passively Equalized Phono Preamp (p. 18): An elaborate discrete circuit. with Alan Hill of Plasmatronics. • The Music (p.199): • The Grounded Ear (p.34): About a Record reviews, seminar on measurements vs audible dis- with raves about a couple of the locally produced Titanic discs. tortions which took place at last Mays • Special Report (p.218): David AES convention. Shreve discusses the problems of • Audio Aids (p.36): Homebrew mods and hints. achieving correct VTA and the audible effects of not doing so. • Test Report (p.42): Improving the Heathkit AP-1615 preamp; evaluating the

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Logic Systems 318 dynamic noise filter it outstanding), Powerlight MC--4 head (pretty good). amp (.excellent but RFI prone). SAEC SS 300 aluminum platter mat (liked better than any soft mat). Spectra AUDIO ENGINEERING SOCIETY JOURNAL, Disc Cushion elastomer platter mat May 1980 (.very good). Sumo "Power" power amp (very powerful and very good). Sumo • Time Delay Spectrometry (p.302): "Gold" power amp (class A, potent, its Some of the uses of Heysers technique extremely good but its fans are noisy). for making time-gated measurements. • Interconnecting Cables: Fully half • Amplifier-Loudspeaker Interfacing of the issue is occupied by subjective (p.310): Prof. Greiner analyzes some reviews of two dozen sets of patch cords effects of speaker cables and fuses. (speaker cables will be treated in the No, speaker cables dont behave as next issue). Dramatic differences in transmission lines. sound are attributed to the various • Phonograph Signal Rate of Change connecting cables, but no attempt is ( p.316): Measurements of the slew made to rationalize these or correlate rate of phono signals in assorted them with any measurements. Sample recordings: the worst-case value, comments: "metallic top end, stridency, transferred to the output of a 100W compression of stage size and dynamic amplifier, is 2 volts/microsecond. range; heavily veiled, deficient in • Phonograph Preamplifier Design Cri- ambience and air, the cables add a teria (p.325): Tom Holman updates his rather grainy layer of distortion; their definitive study with emphasis on TIM, high end is a bit brash, and both ex- RFI, and the modified square-wave test treme low bass and upper treble are signal missing; wide midband hump; the losses of this and every other cable are bla- tantly obvious; these cables ... turn AUDIO ENGINEERING SOCIETY JOURNAL, a concert grand into a bar-room upright; June 1980 timbre and harmonic structure are altered • Loudspeaker Testing (p.402): A to a radical degree; these cables are description of the measurement system very restricted in bandwidth, showing used at CBS Labs for High Fidelitys a sharp drop in amplitude in both upper speaker reviews. treble and lower bass; as with the • Loudspeaker Driver Phase Response Mitch Cotter .. cables, dynamic range (p.410): Accounting for driver phase is also very highly compressed; thick response in crossover design. blanket of haze engulfs everything; • Automatic Frequency Control in FM steel wire tends to sound brash and Tuners (p.422): Details on Kenwoods metallic, while silver-clad wire has DDL Distortion Detector Loop which the tendency to ring -- usually vio- automatically tunes to the lowest- lently." These startling claims, while distortion point in the FM channel. implausible, are intriguing and tanta- lizing, so at CES we asked editor/pub- lisher Len Hupp whether he could specify AUDIO HORIZONS, Vol. 1 No. 4 any system of components costing under • Reviews: Cramolin contact cleaner $10,000 in which these differences in cables would be audible. He couldnt; recommended for removing oxidation ( his tests employed mainly custom-made from metal-to-metal contact surfaces), components. So independent verification Dynavector Karat/Ruby m.c. cartridge of his claims will be difficult. (terrific). Dynavector Karat/Diamond (the worlds best, but VTA is criti- cal). Hafler DH-200 power amplifier AUDIO TIMES, May 15, 1980 (good, alleged to be even better when its output bias is raised above the • News items: GAS, verging on bank- factory-set value of 200 mA) . Linn ruptcy, is looking for a buyer. Stax Ittok tonearm (fussy but superb). and Denon are setting up their own U.S. Marcof glass platter mat (_better than import offices. Tech HiFi and Tweeter comparable felt and rubber mats). are both getting into video retailing. Michaelson-Austin TVA -1 tube power Numerous VCR manufacturers are devel- amp (very good). Micro Seiki BL-91 oping models with Dolby noise reduction turntable (a very good belt drive), for audio, and Dolby is also working on Musical Fidelity BB-1 head amplifier a video noise reduction circuit for VCRs (battery powered, very good). Oracle to eliminate colored snow in pictures. turntable (good in its stock form, replacement of its - platter mat makes

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AUDIO TIMES, July 15, 1980 High Fidelity 80 (p.78): Goodies seen at a hifi show. • News items: Audio-Technica has • Reviews (p.91 ) : Monitor Audio MA84 bought Design Acoustics and will speaker (well made, slightly bass- expand the speaker line. Sony has heavy tonal balance). Grundig CT-5500 demonstrated a prototype 4½ lb video cassette deck (flexible controls, bias camera/recorder combo, hoping to trimmer, good performance). establish it as the standard suc- cessor to 8mm film before marketing it in 1985, And Sony has joined HIGH FIDELITY, June 1980 forces with Philips. to refine and promote the latters 4/ inch Compact • The Autophile (p.11): Surveying new Digital Disc system, hoping to get car stereo stuff. it accepted as the worldwide standard • Equipment Reports (p.28): JBL L-19 digidisc format before marketing it speaker (compact, efficiency is low, in 1982-83 at $500. Philips will back power handling high, pretty good sound). it with lots of releases on the DG, Boston Acoustics A100 speaker (wide Philips, London, and related labels, dispersion, unsually uniform response, while Sony will release many CBS good imaging, impressively uncolored recordings. sound). Infinity RS speaker (forward, gutsy sound, low impedance, some 3 kHz ringing, otherwise good). EPI 120C DB, July 1980 loudspeaker (_smooth, good bass and crisp top, good depth imaging). Cerwin-Vega Theory and Practice (p.10): On dynamic range and how the human hear- HED U10 loudspeaker (relatively efficient, smooth except for an obvious irregularity ing mechanism provides dynamic come at the 2 kHz crossover, tweeter somewhat pression. • beamy, otherwise OK). Note that the Digital Audio (p.22): First magazine is including a metronome in installment of a continuing series speaker photos as a convenient index of on basic concepts of digitized audio. relative size. Good reading. • AES Los Angeles (p.42): • Living with Loudspeakers (p.50): Mark . Notes on Davis and five speaker designers exchange last Mays convention, including the views about speaker/room interaction, hotly disputed demonstration of muscle fatigue induced by digital sound. radiation patterns, appropriate test and design parameters, stereo imaging. If We Can Hear It, We Can Measure It (p.49): Moderated by Peter Mitchell. About testing facilities • Seven Myths of Speaker Buying (p.55): at KEF, plus reports on tests conducted Advice for novice shoppers. at the London AES convention in Feb- ruary in which engineers listening to • The Trouble with Orchestras (p.58): Gunther Schullers trenchant and widely A/B comparisons could not hear 9th- discussed diagnosis of our symphonic order 20 kHz filters nor soft clipping discontent, identifying ignorant trustees, but could easily hear hard clipping and/or a 10 kHz filter. jet-set conductors, and cynical players among the villains.

GRAMOPHONE (England), May 1980 HIGH FIDELITY, July 1980 • Reviews (p.1726): IMF ALS30 loud- Crosstalk (p.11): speaker (low efficiency, good perfor- • Qs and As. This column formerly entitled "Too Hot to mance at the price). STD 305M turn- Handle", table (an excellent belt drive, close • Equipment Reports (p.21): Marantz to the Linn in performance). Sony 2000 receiver (very good tuner,, good MDR-3 headphones (very light, comfor- preamp, infrasonic filter, conservatively table, sound pretty good). QED 26/2 cartridge equalizer (provides flexible rated amp with lots of dynamic headroom and output current; an excellent budget switch selection of load capacitance receiver). Sony V25 receiver (very good and resistance, well made). Zerostat Z-track tonearm damper (similar to the tuner, very quiet, preamp good but has no infrasonic filtering at all, power Disctraker but different in detail, amp is good at 8 ohms but current-limited well made, works well, recommended). at 4 ohms, front-panel design is superb). Akai R-30 receiver (good tuner, flexible taping connections, infrasonic filter GRAMOPHONE, June 1980 with some deep bass rolloff, amp is good • Sounds in Retrospect (p.77): Sonics at 8 ohms). Teac 650R cassette deck of recent discs reassessed. (bidirectional record/play, works well,

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alignment good, performance good, fast HIFI NEWS RECORD REVIEW, June 1980 peak-reading meters). Modular Acous- • The Role of the Recording Engineer tics 3000 loudspeaker (plays loud, (p.57): The evolution of pop recording high power handling, strong bass, methods. sweet treble, some roughness around • Analog vs Digital (p.62): Comments the crossover). Adcom Crosscoil XC/LT on digital studio equipment and its m.c. cartridge (light weight, high implications for the future. output, no head amp needed, line-trace • Record Pressing Faults (p.77): It stylus, smooth response, internally seems that British pressings are no damped). longer paragons of quality. • Cassette Tape Tests (p.32): Tests • American Record Quality (p.87): In of 6 ferric 4 chrome-equivalent, and direct comparisons American pressings 7 metal-particle tapes. Test parame- are still worse except for HNH and other ters are well chosen, yielding useful small independents. results; note the best-buy performance • Reviews (p.124): JR EX1 amplified of RKO Ultrachrome (.DuPonts second- subwoofer (generally good, but not a true generation chrome oxide). "sub" woofer, rolls off below 40 Hz). • Record Cleaners (p.43): A users Hafler DH-200 power amplifier (kit is survey of disc-care products. easy to assemble, conservatively rated, very slight crossover distortion at high frequencies, plenty of output current, HI-FI NEWS RECORD REVIEW (England), drives reactive loads well, excellent May 1980 value). Four receivers (ranked as fol- • The 1980 Shows (p.72): New stuff lows, Yamaha 840, Kenwood 850, Marantz seen at shows in three cities. 4000, JVC RS-7, but the differences were • Analogue vs Digital (p.83): An judged to be slight). intriguing, detailed comparison between the Sony PCM 1600 digital recording system and the top-line Ampex ATR 100 MODERN RECORDING, June 1980 analog deck. The Sony looks awfully • Audio From London (.p.60): Notes on good, its main flaws being distortion the. AES convention tests of the audibility at ultra-low signal levels and a bit of clipping and anti-aliasing filters. of mild ringing on high-frequency • Lab Reports (p.62): Sanyo N55 "Super transients probably caused by the D" noise reduction unit (a two-band 2:1 antialiasing filter. compander, works very well, is incompatible • Subjective Sounds (p.89): Notes with other systems). Onkyo 2080 cassette on the audibility of anti-aliasing deck (.automatic AccuBias feature works filters and soft clipping (the AES well, has Dolby rec cal, best response experiment); the Technics SL10 clam- obtained with ferric and metal tapes). shell record player. Ramko ARA-1612 electronic patchboard • The Trackability Factor (p.91): A (costs $3000, a super-convenient way of study of the factors governing the routing signals). Lexicon Model 93 tracking ability of cartridges. Prime Time digital delay (a high quality • Las Vegas (p.97): Report on the mono pro unit with flexible special Winter CES. effects as well as delay). • Reviews (p.143): KLH 3 compact speaker (good imaging, amazing bass for its conveniently small size, some MODERN RECORDING MUSIC, July 1980 midrange coloration). Audio Pro AA14 speaker (biamplified with built-in • Ambient Sound (p.661: About the audio amps, plays loud, relatively compact, of videodiscs and the choice of format good imaging, good sound). for digital discs. • Five Tonearms (p.150): A compara- • Lab Report (p.70): A comparative test tive review paying special attention of seven premium open-reel tapes, with to structural resonances and flexure. no useful conclusion; the testers did All five exhibit poor tracking geometry not optimize the bias for each tape, when installed per instructions but making the tests nearly useless. are OK when aligned with an external protractor. Rankings: Audio Technica AT1100 best, Lustre GST 801 (medium- POPULAR ELECTRONICS, June 1980 high mass, resonance-free), Ultracraft • Audio (p.18): About fitting the AC300 Mk II, ADC ALT-1, Infinity Black dynamic range of digital recordings Widow (worst, severe resonances, the into the home environment. supplied arm damping is ineffectual). • Reviews (p.22): AKG K340 headphones Ariston RD-11S turntable (belt drive, (dynamic woofer, electrostatic tweeter, good performance, isolation superb in plays loud, sounds very good). Sansui audible range but poor below 20 Hz).

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G-5700 receiver (.very good in most ness and strengths; for example the respects). Onkyo 7090 integrated Pioneer KE 5000 exhibited the best tuner amplifier (conservatively rated, has sensitivity but its tape player had the lots of output current and dynamic worst flutter). headroom, dynamic power exceeds 300W per channel at 4 and 2 ohms; good infrasonic and ultrasonic filters but RADIO ELECTRONICS, June 1980 a bit of deep bass rolloff in the The History of Television (p.43): Lots phono stage; • flexible tone controls, of interesting facts. impressive performance overall). • Digital Audio (p.63): An intro to PCM • Video Test (p.45): Henceforth PE circuitry in general and the EIAJ-standard publishes insightful reviews of video VCR converters in particular. products. First test: RCA CTC108 color TV chassis used in various new XL100 models (makes much use of ICs RADIO ELECTRONICS, July 1980 and solid state filters including a SAW filter for clean IF response; • Small Speaker Systems (p.59): Reviewing has a sensitive tuner, full 4 MHz the tradeoffs among size, low-end response, bandwidth circuits, 3.5 MHz at the efficiency, and enclosure type. picture tube; overall video perfor- • Review (p.70): Audio Control C-101 mance is quite good at the price). equalizer/analyzer (poor control labeling, • Video Cassette Recorders (p.51): A excellent performance, good value, pink good introductory article on how they noise generator and microphone included, work. analyzer accuracy is good).

POPULAR ELECTRONICS, July 1980 STEREO REVIEW, June 1980 • Pseudoacoustics (p.18): Favorable • Audio Q A (.p.22): Common sense about comments on the Carver and Omnisonix car stereo. image enhancers. • Audio Basics (p.28): Car hifi in the • Audio Reviews (p.22): Hafler DH- old, old, old days. 200 power amp (potent, lots of dynamic • Tape Talc. (p. 30) : Q A. headroom and output current, dynamic • Technical Talk (p.36): On measuring output exceeds 300 watts at 4 ohms amplifier distortion. and nearly 500 watts at 2 ohms, drives • Test Reports (p.40): Aiwa 7800U re- reactive loads easily, kit assembly ceiver (digital frequency synthesis, easy, an outstanding bargain). Vector superb tuner performance, amplifier is Research VCX-600 cassette deck (three clean and smooth, good dynamic headroom heads, bias trimmer, excellent per- especially at low impedances, good pre- formance, inadequate headphone output). amp section). Audio Technica ATH-7 Avid 100 loudspeaker (neutral, crisp, headphones (electret drivers, some dis- transparent, relatively efficient, tortion at very low frequencies, very excellent transient response, spacious smooth. overall response, bass is sub- sound, excellent value for money). jectively good, phones are unusually • Video Test (p.47): Magnavox T809 comfortable). Boston Acoustics A100 color TV chassis used in various 19" loudspeaker (impressively smooth response, models (mediocre tuner sensitivity, outstanding dispersion, spacious imaging, full 4 MHz bandwidth all the way to clean bass, excellent price/performance the picture tube, uses comb filter to value). Marantz SD-9000 cassette deck maintain maximum color resolution, (extremely elaborate controls and micro- unusually fine video performance). processor, three heads, bias trimmer, • Low Cost Analog Delay Line (p.53): solenoid controls, excellent performance Just what weve been waiting for, a at standard speed and superb performance good-quality stereo delay costing only at 3.75 ips). ReVox B760 tuner (digital $250 in kit form. Uses the Signetics frequency synthesis, $1700 price tag, compander IC for noise reduction and "supertuner" specs, sensitive, excep- the Reticon SAD 4096 IC for clean tional interference rejection, 15 station delay. The kit is not excessively memory, but doesnt retain selected complex, and performance is likely to station when switched off). be very good. • Car Stereo (p.61): A thorough survey • Car Stereo (p.63): Lab tests of of features and selection criteria. car stereo units: FM, tape, and amp • War of the Videodiscs (p.69): A sections tested separately, with close look at the sound quality which interesting results. No overall is potentially available from videodiscs rankings, as models had varying weak- (whose sound is encoded in FM).

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STEREO REVIEW, July 1980 HIGH FIDELITY (circ. approximately 350,000), pickier equipment reviews, • Audio Q A (p.20) : Stereo AM, the good feature articles, lots of classical problem of amplifiers wearing out, etc record reviews. Subscriptions officially • Audio Basics (p.24): Tone controls $13.95, discounted regularly to $9.98 are there to be used. and occasionally to $6.98. Subscription • Tape Talk (p.26) : More Q A. address: 1 Sound Avenue, Marion OH 43302. • Technical Talk (p.31): Making A/B comparisons with the fine comparator AUDIO (circ. 150,000), originally devised by the Southeast Michigan for engineers, now tries to straddle the Woofer and Tweeter Marching Society. range from engineers to novices. $11.94 • Test Reports (p.34): Adcom GFA-1 in U.S., $17.94 overseas, to Box 8168, power amp (potent, plenty of dynamic One Fawcett Place, Grennwich CT 06835. output at all impedances, the included HI-FI NEWS RECORD REVIEW, Englands fan is quiet; very good price/per biggest (150200 pages per issue, over formance value). Dynaco A-150 speaker half ads) and one of the worlds best (smooth, brilliant, good value, but hifi mags, with informed reviews pro- its low-frequency power handling is viding a nice mix of measurements and limited). Garrard GT 350ap turntable listening tests, interesting columns (smooth automatic operation, low-mass and features, and record reviews which arm, good geometry, mediocre vibration rate both sound quality and performance. isolation). Koss HV/X headphones $35.00 U.S., £ 13.00 elsewhere. Link (comfortable, can play loud, fairly House Publications Ltd., Robert Rogers smooth response). Sansui 7700 re- House, New Orchard, Poole, Dorset BH15 ceiver (a powerhouse, lots of dynamic 1LU, England. headroom at all impedances, preamp section is okay, tuner pretty good). GRAMOPHONE, the English-speaking • Listening Tests (p.52): An intro- worlds leading record-review magazine, ductory essay on reviewing philosophy assessing more records (and cassettes) by Larry Klein, plus a thorough survey in each. issue than you ever imagined of the methodology of valid listening could exist. Air mailed to U.S., $27 comparisons by Shure engineer Lynn per year, $51 for two years. General Claudy. Gramophone Publications Ltd., 177-179 • Remote Control (p.60): Convenience Kenton Rd., Harrow, Middlesex HA3 0HA , is the coming trend. England. HI-FI CHOICE, not a magazine but a Peter Mitchell continuing series of paperback books, (Massachusetts) each. volume containing 50 to 100 reviews of products in a single category, per- mitting detailed comparisons to be made. (The current volume on Cassette Decks and Tapes is excellent.) Each review Subscription Data includes lots of measurements and a listening test. Each volume costs £ 2.50 (about $5.75) including postage to the Herewith, by popular request, U.S. Sportscene Publishers Ltd., 14 information on the publications which Rathbone Place, London W1P 1DE, England. are abstracted in the IN THE LITERA- TURE column, and a couple which are STEREO, a quarterly magazine with not. First the "slicks," whose thoughtful and informed reviews, available operating costs and profits come only on newstands, unfortunately not by mainly from advertising income while subscription. the subscriptions and cover price POPULAR ELECTRONICS (circ. 450,000), pay mainly for getting the mag to you. Monthly except where specified. covers the whole field of electronics including short-wave, video, computers STEREO REVIEW, the biggest (cir- and hobby circuits as well as audio. culation approx. 550,000 per month), Sub. officially $14, generally discounted generally the clearest and most free to half of that. Box 2774, Boulder CO of errors and ambiguities, as befits a 80302. mag addressed mainly to hi-fi learners RADIO ELECTRONICS, originally for rather than engineer/audiophiles. Sub- radio-TV service technicians, broadened scription price officially $9.98/yr, to include audio, short wave, electronic discounts to $4.99 widely available. games, VCRs, satellite TV, etc. The Subscription address; Box 2771, audio reviews are the weakest part of Boulder CO 80321.

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the mag; the feature articles, video tratingly slow or gratifyingly rational coverage, and construction projects depending on your viewpoint. $12 U.S. the best. $13 to Box 2520, Boulder ($18 overseas) to Box 1949, Sata Fe NM CO 80321. 87501. MODERN RECORDING MUSIC, aimed AUDIO HORIZONS, appropriately named mainly at musicians trying semipro since its observations tend to be at the recording in basement/garage studios fringe of perception, though in truth using a mix of hi-fi and pro gear. its not much farther out than some of Not error-free. Features descriptions the others. $16 ($24 overseas) to Box of pop recording sessions. $14 to 10973, St. Louis MO 63135. 14 Vanderventer Avenue, Port Washing- ton NY 11060. The next batch are "pro" journals intended for people making a living in The next batch are "underground the audio field. ers", i.e. supported mainly by sub- AUDIO ENGINEERING SOCIETY JOURNAL, scription rather than mainly by adver- the forum in which audio engineers pro- tising. Quarterly except where speci- pound design theories and explore the fied. fundamentals of acoustics. Sometimes AUDIO AMATEUR and SPEAKER BUILDER, heavily mathematical. 10 issues/year. Ed Dells two "do it yourself" quar- Nonmembers $45, subscription included terlies mixing construction projects, in $35 member dues. 60 East 42nd St., explanations of theory, and debates on New York NY 10165. the issue of measurements vs listening, WIRELESS WORLD, the other big English plus reviews. Recommended, and not language engineering journal, full of just for solder-gun users. $14 and circuit designs and theory, the Bible $10 respectively to Box 576 and 494 of the working design engineer. Monthly. respectively, Peterborough. NH 03458. $31 (includes postage to U.S.), payable THE ABSOLUTE SOUND, the biggest to IPC Business Press Ltd., Oakfield subjective review mag in both word House, Perrymount Road, Haywards Heath, count and circulation, and with a staff Sussex RH16 3DH, England. of reviewers instead of a monolithic RECORDING ENGINEER/PRODUCER, the viewpoint. Lengthy reviews of equip- ment and recordings; understandably largest and most comprehensive of the mags focusing on professional recording, popular. $20 ($30 overseas) to Box L, concert sound reinforcement, and film Sea Cliff NY 11579. sound; with background features on INTERNATIONAL AUDIO REVIEW, in acoustics as well as hardware-oriented form more like a book than a magazine, stuff. Six issues/year. $10 ($19 over- in frequency more like an annual than seas) to Box 2449, Hollywood CA 90028. a quarterly. Reviews, clear explana- STUDIO SOUND, the main British mag tions of physical principles, and for microphonists, consists mostly of large doses of epistemology. As we practical hardware features and reviews. go to press, IAR has just changed its form to a monthly "Hotline" bulletin Free to recording and broadcasting pro- fessionals, otherwise $30/yr (including supplemented by quasi-annual book postage to U.S.). Same address as Hi- length volumes. $29 ($49 overseas) Fi News Record Review. for four large volumes or equivalent. 2449 Dwight Way, Berkely CA 94704. DB magazine, the other American periodical about recording, broadcasting, THE AUDIO CRITIC, the haughtiest and PA sound. Generally avoids heavy mag of the genre, uses lab tests as math, emphasizes introductory features. well as listening evaluations, but Monthly. $12 ($24 overseas) to Sagamore prints only the conclusions and recom- mendations, not the supporting data. Publishing Co., 1120 Old Country Road, Plainview NY 11803. Tantalizing, interesting, well written, and arrogant. $30 for six issues ($36 PRO SOUND NEWS, a newsmagazine about overseas) to Box 392, Bronxville NY the recording and concert sound fields. 10708. Free to recording/broadcasting pros. 220 Westbury Avenue, Carle Place NY 11514. STEREOPHILE, the original (.and still the most commonsensical) non-- The last group is the "trade" maga- commercial subjective review mag. Editor/publisher Gordon Holt waits zines intended to be read by retailers and other people in the commercial audio for product designs to stabilize before business. reviewing them, which is either frus- These mags are totally adver

1 1 tiser supported and are distributed on equipment chassis, probably arising free to people in the trade. The list from stray capacitance between the includes CONSUMER ELECTRONICS, HIGH primary winding and the core of the FIDELITY TRADE NEWS, AUDIO-VIDEO power transformer in each product. INTERNATIONAL, SIGHT AND SOUND, AUDIO ( These leakage voltages are generally DIGEST, and several others, but the not dangerous because the associated trade publication of greatest appeal leakage-path impedances are high, limit- to audiophiles probably is AUDIO TIMES, ing leakage currents to very small values. a twice-monthly newsmagazine whose But some audio components do produce a contents include new-product announce- noticeable tingle when the front panel ments, sales trends, news of corporate is stroked lightly with a fingertip.) mergers and bankruptcies, executive Of course the presence of leakage hirings and firings, interviews about voltage on the chassis of a single com- product marketing plans, etc. Free ponent is of no consequence. The problem to the trade, otherwise $40/year. Box identified by Mr. Egawa is that when two 5117, Westport CT 06880. components having differing leakage po- tentials (e.g. a preamp and a power amp) . P.S. For most of the magazines are connected together, leakage currents listed above, the rate for Canadian flow through the shields of the audio subscriptions is $1.00 more than the signal cables together with audio-signal U.S. rate, payable in U.S. dollars. currents. Since the leakage currents -- PWM are electrostatically induced in each chassis, the leakage is not a pure 60 Hz hum signal; it is a buzzy, highly distorted waveform with many harmonics of 60 Hz spanning the midrange spectrum. The reality of these AC leakage Special June Meeting signals was demonstrated at the meeting. An AC digital multimeter showed the On June 22 about 60 members leakage voltage on the chassis of a gathered at the Marriott Hotel for a preamp and a power amp and large dif- special meeting featuring several ferences in leakage potential between guests from Japan: Saburou Egawa, a the two, varying with the orientation noted free-lance audio consultant and of the AC power plugs. With the meter columnist for a major Japanese stereo connected between the preamp and power magazine; Naotake Hayashi, founder amp a leakage current of 13 microamperes and President of Stax Industries; was measured. Then, with the two products Osamu Fukagawa, assistant manager of connected via a patch cord, a battery- Stax Kogyo (U.S.) in California; and powered Ivie spectrum analyzer was used ( not from Japan) John Taylor, New to show the spectrum of the voltage drop England sales rep for Stax, Tandberg, developed across the patch cord resistance and other manufacturers. This special by the leakage current; but in this meeting was arranged by Mr. Roland case the displayed signal was diagnosed Small, a BAS member who plays the by member Charles Pike as being due at bassoon in the Boston Symphony; Mrs. least partly to radiated hum picked up Small, who is Japanese, assisted with. by the test leads. translations during a SHOP TALK inter- To demonstrate the sonic effect of view the day before the meeting. AC plug reversal Mr. Egawa used a pair Mr. Egawa began by reporting his of Sony C48 condenser microphones, a discovery that the sound of audio com- mike preamp, a Stax SRM-1 headphone ponents can be significantly altered amplifier, and Stax SR-Lambda electro- by using heavy-duty AC wiring and -- static headphones. The demonstration surprisingly -- by reversing the was not a controlled double-blind test, orientation of AC plugs in wall sockets but various BAS members were convinced Of course, back in the tube era it was that a subtle difference in apparent commonplace to find that AC plug ori- timbre was indeed perceived when the entation affected the level of audible headphone amps AC plug was reversed. hum; but Egawa discovered that the Mr. Egawa suggested two implications reproduction of transients and stereo for his discovery: that audiophiles imaging in modern components (whose should experiment with AC plug orienta- hum level is subaudible) is affected tion, and that designers should explore by AC plug reversal. Investigating, the possibility of powering the entire he found that plug reversal yielded stereo system (except for the high- altered levels of AC leakage voltages current output stage of the power amp)

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from a single large power supply. (.Does company now manufactures a full product this mean that we should give up our line except for turntables. Current elaborate component systems and go models include the ELS-4x and ELS-8x back to using all-in-one stereo re- full-range electrostatic loudspeakers ceivers?) Another alternative, which ( $2400 and $3600 respectively), a might have more appeal in theory than broad range of preamplifiers and pure in practice, is to use 1:1 isolating class A amplifiers, several tone arms, transformers in the signal path from the CP-Y condener phono cartridge.. the the preamp to power amplifier. CS-2 tone arm stabilizer, and -- the most popular category of Stax products Mr. Egawa provided another rather -- a half dozen electrostatic headphones startling demonstration with the head- called "earspeakers" with a variety of phones, this one relating to Kenwoods adapters and preamps to drive them. recent claims about "magnetic distor- The headphone models range from the tion" of signals in audio components $120 SR-44 (which uses electret trans- due to the proximity of wiring to metal ducers and so does not require a high- parts. Egawas C48 microphones, like voltage polarizing power supply) up to other high-quality condenser mikes, the $390 SR-Sigma (in which the drivers have internal FET impedance converter/ are mounted away from the ear at an preamps which are powered by 9-volt angle, at the front of an open cage so alkaline batteries. But the usual that the outer ear performs its usual metal jackets of these batteries were tonal and localization functions). removable, leaving only a cardboard jacket around the battery electrolyte. A principal focus of current interest Remarkably, removal of the metal sleeves at Stax is the "super shunt" power supply, from the batteries appeared to produce developed for the $3500 CA-X preamp and a clearly audible change in the tonal also being applied in other products quality of the microphones. That is, including the DA-100 power amp, a tuner, the presence or absence of the metal and a condenser microphone. For com- battery jacket from the battery com- parison, a conventional power supply partment within the microphones case consists of a transformer, rectifier, ostensibly altered the sound of the filter capacitors, and (except in power mike. Such startling behavior obvious- amplifiers) a voltage regulator. The ly invites further study. active circuitry of an audio product (its transistors and ICs) comprise a The latter half of the meeting was "load" which draws varying amounts of occupied by discussions and demonstra- current from the power supply in response tions of Stax audio components. The to the audio signal; and to complete history of Stax reflects the personal the circuit all of the load current history of the companys founder and finally flows back through the circuits President, Mr. Naotake Hayashi. He ground paths to the "neutral" side of studied radio engineering in the 1920s the power supply, e.g. the negative and was involved in the early spread terminal of the filter capacitors or of broadcasting in Japan. During the the center tap of the power transformer. 1930s he went to China and assisted In theory this works fine, but in the a Shanghai record manufacturer to con- real world the ground paths in the cir- vert from acoustical to electrical re- cuit always have some finite non-zero cording, which got Mr. Hayashi involved amount of impedance; consequently the in the design and manufacture of audio varying ground currents produce varying products, particularly amplifiers, signal voltages along the ground paths. microphones, and light-tracking phono cartridges for use by recording engi- To eliminate varying ground currents neers trying to evaluate the quality Stax adds a "shunt" regulator to the of wax and acetate master discs. In output of the power supply, in parallel 1938 he founded Showa Koh-On Kogyo, with the load, designed to keep the the parent company of Stax in Tokyo. supplys output current constant as well as its voltage. When the load The modern phase of Stax began draws more current the shunt draws less with the development of a condenser so as to keep the total constant. Thus microphone in 1952, an electrostatic the total current flowing in the circuit speaker in 1954, a modulated-RF phono -- and through the ground paths -- is cartridge tracking at only 1 gram (at constant, and the ground paths are no a time when anything under 6 grams was longer "live" with signal-related vol- considered low), and the first electro- tages. As a further benefit, thanks to static headphones in 1959. Stax today the constant drain on the supply, the continues to be dedicated to the use power supply voltage is no longer subject of electrostatic transducers, and the

1 3 to. modulation by varying signal demands; Peter invited comments on the use- the power supply is perfectly stable and fulness of the IN THE LITERATURE column noise free, and crosstalk and distortion in its present form. Are the detailed due to power supply modulation cannot citations and summaries of reviews useful? occur. Should the column be abbreviated? Should we seek to include more publications like To conclude the meeting, recordings underground quarterlies and foreign maga- were heard through a system including zines? About 25 people indicated that the Micro-Seiki RX-5000 turntable, they use the column and look up articles Stax CA-X preamplifier, two DA-100 referenced in it, while many others felt power amplifiers, and ELS-8x speakers. that its detailed summaries are adequately The sound was not spectacular, loud, informative, and they need not go to the or "hi-fi" in quality; it was just original. The column will continue in uncommonly musical, unstrained, and its present format for the near future. very smooth and transparent. The demonstration recordings included a Publication and mailing of the SPEAKER pipe organ tape recorded by Brad Meyer is still behind schedule, but the practice and Peter Mitchell, and a remarkable of having two editors working on issues record of "Early Hi-Fi and Stereo" in parallel is expected to help bring the loaned by member Elbert Drazy; it is scheduling back up to date before the end a compilation of recordings of Stokowski of this year. and the Philadelphia Orchestra made by Bell Labs engineers in 1931-32, MEETING FEATURE -- DANIEL QUEEN AND including two excerpts in genuine TONY FEDERICI stereo! The focus of the meeting was on aural -- PWM imaging and on two products whose distri-

bution is being handled by Anthony Federici: the Schieber Sonics 360-degree spatial decoder, and the Daniel Queen Regular June Meeting model CA2 loudspeaker whose uniform 360 degree radiation pattern is intended to yield improved acoustic image localization On June 29 about 70 members con- and clarity. vened at GTE. During the "open forum" portion of the meeting the principal The head of Daniel Queen Associates, subject of dicussion was the abrupt a Chicago R D firm, Dan Queen is also a cancellation of SHOP TALK, the weekly member of the Acoustical Society of Amer- show about high fidelity and music on ica, SMPTE, IEEE, and has been elected a WBUR hosted by Peter Mitchell, Dick Fellow of the Audio Engineering Society. Goldwater, and Brad Meyer. Peter took He has served on many committees in these professional organizations and has pub- some time to explain the apparent circumstances leading up to the. sudden lished a number of papers in the field disappearance of the program from the of audio. In his talk he reviewed his air. Evidently the current station investigations of factors which affect manager, Jane Christo, is punishing the ability of a listener in a room to the SHOP TALK crew for having the localize the aural image of a sound source temerity to disagree. privately with. in the presence of wall reflections. her about the conduct of a hi-fi equip As a young boy growing up in Boston ment auction at the station in May. Daniel Queen had an avid interest in audio Listeners who call WBUR to protest the equipment and music. He recalls hanging shows cancellation are being told that around the original Radio Shack store, it is on vacation and will return in then on Washington Street near Scollay the Fall. Square, where their demo room had a switch On BAS business, a few volunteers box for comparing speakers and amplifiers. are needed to write these meeting Some of the popular speakers of the day reports for the SPEAKER. With several were the Stevens Tru-Sonic, the Altec people to share the task, each author Voice of the Theatre, and the Jensen bass need only write up two or three meet- reflex box, which could be adjusted for ings per year. Assistance is available the desired degree of boom. His hi-fi in the form of an audio tape of each system (mono, of course) included a GE lecture and final polishing of your 1201D speaker installed in a Jensen re- syntax by the Editor. Finally, to flex cabinet. add a little incentive, you will be On the musical side Mr. Queen recalls paid $40 for each report. If youre standing in the 10:00 AM "rush line" at ready to volunteer, or want more infor- mation, contact Brad Meyer. Symphony Hall to get budget tickets for

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the weekly Friday afternoon Symphony Two cylindrically omnidirectional concerts. In the evenings he would go speakers (described below) were set up to the Savoy Cafe or down the street in an anechoic chamber as shown in Fig. to the old Hi Hat to catch a few sets 1, one producing the "direct" radiated in these now-defunct jazz clubs, and sound and the other, spaced 30 degrees then he and some musician friends away from it, producing the simulated would gather in a high-peaked garret "reflection" from the wall which would on Columbus Avenue to listen to be present in a typical listening room. records through another GE 1201 Numbered cards positioned between and mounted up high, near the ceiling. beyond the two speakers allowed mem- In spite of its limited low end and bers of a listening panel to identify 6 kHz top, he found that this speaker the direction from which the sound mounted in that room -- sounded appeared to be coming. The test signal quite realistic, remarkably similar was a gated burst of 1/3 octave random (despite its mono perspective) to the noise, with a cosine-shaped envelope live music he had been hearing. This 300 mS in length. The same signal was listening experience has stayed with fed to the "reflection" speaker after him and provided some of the motiva- of a delay of 0, 0.1, 0.3, 1.0, or 3.0 tion for his continuing investigation milliseconds at an amplitude of +10,+5, of the factors which influence the way 0, -5, and -10 dB relative to the "di- loudspeakers sound in rooms. rect" speaker. The noise bursts were centered at three frequencies: 250 Hz, A key point in his initial analy- 1500 Hz, and 6000 Hz, selected because sis of this speakers success, and of of psychoacoustic studies which have other speakers which pleased his shown that localization is strongly musically-conditioned ear, was that dependent on phase (or arrival time) they were all simple systems which differences at low frequencies and upon had relatively smooth and broad dis- intensity differences at high frequencies, persion over much of their frequency range. with the crossover between the two He also recognized that the detection modes occurring at about listening room is an integral compo- 1500 Hz. nent of the reproducing system and that it would be necessary to account All combinations of delay, relative for its effects. This was not simply amplitude, and frequency were presented a matter of grinding through the to listening subjects who were asked to physics of room resonance modes, pick the direction from which the sound boundary reflections, and reverbera- appeared to originate. Results for tion times, but also involved the five subjects were averaged and plotted psychoacoustics of listening. He in Figs. 2-4 for the three frequencies. noted that humans have been listening Each graph shows, for one frequency, the in rooms for thousands of years and apparent image position as a function their hearing mechanism has adapted of the relative intensity of the "re- to this environment. This adaptation flection" speaker; the various delays aids listeners in making sense of the are plotted with different symbols. complex sound fields set up by room The solid curve represents Bauers acoustics and tailors their perception "stereophonic law of sines" which, for of what the speaker is doing. small angles, says that the direction v One such pyschoacoustic effect is of the virtual image depends in a simple involved when a person tries to locate way on the direction of the reflection the apparent source of sound in a room (Θr ) and the intensities of the direct when part of the sound from a loud- (I d ) and reflected (Id) sounds: speaker is being reflected from a nearby wall before reaching the ear. Typically the listener will perceive the source of sound as located some- where between the loudspeaker and The data for 250 Hz and 6000 Hz follow the wall, with its exact position this intensity law fairly closely for depending upon the intensity and arri- all delays tested, indicating that at val time of the reflection. Mr. these frequencies time delays up to 3 Queen described a series of experi- mS are not a significant influence in ments he conducted to determine how determining the virtual image location. the localization of the apparent At 1500 Hz the data are much more scat- source depends on the relative ampli- tered, but if the points for delays tude and phase of the direct and re- below 0.3 mS are removed (being too flected sounds at each frequency. short for typical wall reflections),

1 5 then the data conform more closely to vocal music was played and panelists the Bauer curve. were asked to decide which of ten numbered back-wall positions repre- From these and other considera- sented the apparent location of the tions Mr. Queen concluded that in sound. In the second, a variety of general the apparent location of a mono and stereo recordings were played sound image in a real room with one and panelists were asked which speakers speaker depends almost entirely on they preferred, in a series of A/B the relative intensities of direct and sequential comparisons. and reflected sounds, as predicted by Bauers equation. One might expect, The two experiments are cross- then, that to achieve good imaging correlated in Fig. 7. The vertical from a stereo pair, each loudspeaker axis represents the frequency of should be directional, radiating expressed preferences for a particular primarily toward the listener so that pair of speakers, and the horizontal sidewall reflections would be at least axis represents the specificity of 10 dB below the direct sound. This, localization (the higher the. number, however, places strong restrictions the lower the variance in localization on where the listener may sit or move. judgements). The trend of the curve In addition, Mr. Queen noted, attempts indicates that speakers with the to create a highly directional speaker least ambiguous imaging tend to be usually result in a radiation pattern preferred, ( However, in the direct having strong side lobes whose inten- A/B comparisons the speaker with the sity and direction vary with frequency. strongest apparent bass output was This leads to frequency-dependent ranked first in preference, while Mr. shifts in image position, so that the Queens speaker was ranked second.) fundamental and harmonics of a sound appear to come from different posi- A detailed presentation of these experimental studies can be found in tions in the stereo image. In multi- "The Effect of Loudspeaker Radiation driver speaker systems changes in the Patterns on Stereo Imaging and Clarity", radiation pattern also often occur in in the Journal of the Audio Engineering the crossover region, resulting in , p.368-379 (May instability of the apparent image. Society, Vol. 27 No. 5 1979). An alternative to highly direc- In response to questions, Queen tional speakers is the use of speakers spoke in more detail about the loud- having essentially the same radiation speakers. Each has three drivers: the pattern at all frequencies, so that midrange and high-frequency units are wall reflections would occur at the both contained in the radial horn, same relative intensity at all fre- with a crossover at 3000 Hz. The quencies. Then, while the wall re- 12-inch woofer faces downward into flections would broaden the stereo stage, the precision and clarity of the cylindrical enclosure, with radia- tion from its rear surface emerging imaging would be virtually the same immediately beneath the radial horn, as if there were no reflections. Mr. Queen has designed such a speaker, one and it is mounted with a slight which is omnidirectional in the hori- spacing between the front of its basket and the enclosure; the gap zontal plane; it consists of a radial functions as the slot-load vent for horn mounted above an inverted woofer the enclosure, Thus all of the sound in a cylindrical cabinet as shown in Fig. 5e. Its output is uniform through- emerges over a vertical area only a few inches high without the large out a 360--degree angle within 2 dB. driver spacing and consequent air- To evaluate the effectiveness of path time delays that are common in this design the new speaker was com- full-range speakers. Crossover to pared with four speakers of more con- the midrange occurs at 700 Hz, the ventional design in a listening test stated efficiency is 1.5%, and the involving a total of 42 people (in free-field response is down 3 dB at groups) in a listening room with the 32 Hz, flat throughout most of the five pairs of speakers arrayed along range, and down 9 dB at 20 kHz. A one wall as in Fig. 6. The other frequency-dependent protection cir- speakers ranged in price from about cuit responds to excessive woofer $200 to $850 per pair, and their out- displacement or tweeter heating. The put levels were matched using A-weighted speaker will generate sound pressure noise. The listening panel partici- levels of 105 dB in rooms of up to pated in two tasks. In the first, a 400 cubic meters. The Queen CA2 is localization experiment, monophonic priced at $1245 per side and is on display at Goodwins in Boston.

1 6 Fig. 1. Two loudspeakers were set up in an anechoic chamber for localization experi- ments, one representing the direct sound and the other the sound which would be reflected from the wall of a listening room.

Figs. 2 - 4. Data from the localization experiment is plotted as apparent image position in degrees from the direct speaker versus the relative intensity of the echo speaker for 250 Hz, 1,500 Hz, and 6,000 Hz, respectively. Different shaped points correspond to different delays in milliseconds, as indicated by the legend. 17 Fig. 5. The configurations of the five loudspeakers which were used in the panel test. Speaker (e), the quasi-omnidirectional design, was also used in the localization experiment.

Fig. 6. Listening room plan in which panelists were seated around seven tables. Loudspeaker pairs, as shown in Fig. 5, were located at A - E.

Fig. 7. Degree of speaker prefer- ence in percent is plotted against ability to localize sound image with that speaker for the panel tests.

18 Tony Federici, President of A playback system was set up by Scheiber Sonics, discussed some of Goodwins to demonstrate the Scheiber the problems which have been common Sonics spatial decoder and the Queen in four-channel decoders and ambience CA2 loudspeakers. The electronics extraction systems, which operate included the Mark Levinson ML-1 pre- by detecting the out-of-phase or amplifier and ML-3 power amplifier. random-phase component of the com- Unfortunately one of the rear speakers posite stereo signal. All but the was inoperative, so the full effect of simplest of these spatial decoders the spatial decoder could not be ex- contain logic circuits which con- perienced. Initial impressions of the tinually adjust the gain and phase Queen loudspeakers were generally of each channel in order to enhance favorable, eliciting comments on their the front-back and side-to-side good vertical as well as horizontal separation; the Tate and Scheiber dispersion, their solid bass, and their are generally regarded as the most clean, airy top end. sophisticated of such products. But most spatial decoders, whether simple In the final portion of the meeting or complex, have tended to suffer some of the many BAS members who had from wandering images, diffuse traveled to the Chicago Consumer Elec- localization, and unwanted instru- tronics Show reported on some of the ments appearing at the side or rear more interesting new products seen of the listener where only the hall there. Detailed commentaries on the CES are to be found elsewhere in this ambience should be. issue. Ideally, Federici suggested, one -- John Schlafer should be able to crank up the level of surrounding ambience to any de- sired degree (or at least to a sub- jectively realistic level) without creating a false sound stage at the rear. In many of the older spatial decoders false localization effects and audible gain pumping occurred because the circuits were too slow in their response. The newer Tate decoder is very fast in its logic action, yielding better imaging of transients; but with sustained notes it exhibits unstable behavior which sounds something like tape flutter as the decoder tries to decide where to place the image. What is needed is decoder logic whose speed is sig- nal dependent, adapting itself to the needs of the music. While time-delay circuits have been the most popular approach to ambience reproduction in recent years, Federici disapproves of the high-frequency rolloff which most delay units exhibit in the rear channels. He believes that, since the authentic ambience of the recording site is contained in the grooves of the record, the best method of spatial reproduction is that which best ex- tracts that ambience and presents it around the listener. This is the Scheiber Spatial Decoder, in which all of the problems referred to earlier have been effectively solved. The unit has controls for optimum de- coding of SQ recordings (some of which are still being made, notably by EMI), as well as ambience extraction from un-encoded records. It costs $3000.

A

CES REPORTS by Brad Meyer, David Weinberg, and Peter Mitchell

Editors Note: Stores have been going so McCormick Place is the area I bankrupt and everyone agrees that the covered least well. Among my omis- hi-fi business is in a slump, but sions was the Pioneer audio/video manufacturers continue to introduce demonstration room, which was very new products at their biannual extra- popular and apprently spectacularly vaganzas, the Consumer Electronics well produced. Still, I did catch Shows in Chicago (June) and Las Vegas a few things: (January). An unusually large con- There was a "robot" wandering tingent of BAS members made it to around the main lobby, representing Chicago for the Summer CES this year, Omni magazine, which (who?) was walking the miles of corridors and accosting sightseers and engaging returning with the obligatory 100- them in conversation. It (he?) was pound suitcase full of literature. equipped with a TV camera and a In these pages three members report microphone, and was being remotely on some of the things they saw. To operated by a very clever man who set the stage Brad Meyer presents a spoke (in an absolute monotone) first-timers impression of the Show, through a small speaker in the robots and in the following reports David front. The optics of the CCTV system Weinberg and Peter Mitchell comment were good enough so that the operator on some of the products which caught could read peoples name tags, which their eye or ear. allowed him to startle the unwary in a very satisfying way. He (it) al- ways collected quite a crowd; he A BEMUSED AND ANECDOTAL ACCOUNT OF was an extremely impudent robot. THE 1980 SUMMER CES by Brad Meyer His promotion of his sponsor was direct and to the point: "Do you This was my first Show, and I read Omni magazine?" "No." "You was suitably overwhelmed by the size should. Or else." and complexity of it all. As you may (Attendees at the CES generally know, there are three separate buildings are acquainted with technological toys, in which things happen: McCormick so the sight of the Omni robot wheeling Place, a huge convention hall in the around the exhibit corridors elicits classic tradition, with three levels mainly amusement rather than awe. But of immense open spaces temporarily last year I encountered him in the subdivided into exhibit booths plus street-level corridor of the Palmer some very large exhibit rooms; the House Hotel in midtown Chicago, where adjacent McCormick Inn, which has he (it) was blowing the minds of inno- medium-large open exhibit spaces on cent civilians unconnected with the the lower floors and hotel rooms on CES. To the technically unsophisticated the upper floors; and, about two its not obvious that he is operated miles uptown, the Pick Congress Hotel , by wireless remote control. At first which has regular hotel rooms of the glance he seems completely convincing sort used for the AES convention at as a genuine, self-motivated (and the Waldorf in New York. I. McCORMICK PLACE frighteningly intelligent) robot or, at the very least, a metal uniform with a little man inside! -- PWM) McCormick Place is the zoo. There you will find the widest variety of Video-related components are exhibitors and the most outrageous going to be big next year. Small and amusing promotions. Having been forays into the field are being made to AES conventions before I felt more by companies marketing things like a at home in the smaller exhibit areas, tuner that picks up the sound off of

2 1 the television channels and sends it as tentative, maybe even highly sus- to your preamp. A young lady at one pect, because of the extreme variations booth told me that the device she was in room acoustics, source material, promoting provided the TV sound in and associated equipment. After a "stimulated stereo." Must be for the while one listens for flaws so severe X-rated movies theyre sending over that they show through all the other the cable late at night. variables in the situation. I have not had a chance yet to confirm or Speaking of X-rated movies, the deny any of these judgements since porn videotape merchants were back I got back. this year, apparently having toned down their displays considerably. Les Tyler of dbx was demonstrating ( Yes, they were less blatant, but their new microprocessor-controlled they occupied twice as much floor equalizer/analyzer, the Model 20/20. space, which testifies to the pros- By the time I heard thd demo he had perity of the business. -- PWM) done it quite a few times, and he was Last year they were simply showing really slick. The 20/20 will feed uncut versions of their wares; the pink noise into your system and auto- one booth I visited in June was matically set its octave-band controls showing what might literally be to achieve flat response at a given called "teasers," meaning previews microphone position within about ten that would themselves been rated R seconds. It can store several different at most. VCX, one of the largest correction curves and switch between video distributors, had Marilyn them at the push of a button, and can Chambers at their booth signing add a pre-set amount of top-end slope autographs. I didnt see her; some- to any stored curve at the flip of a one who did told me that the over- switch, a handy feature as those of riding impression was that she looked you will know who have heard records tired. played over a system with flat response. Initially they used a pair of AR-9s On the last day of the Show I to demonstrate the device, but the 9s stopped by an automotive accessories were sufficiently close to flat to booth, and while there I suddenly begin with that the difference made heard loud disco music coming from by the equalization was rather subtle. the other side of a cloth partition. This made the demonstration ineffective; Surprised that such a manufacturer when your audience has been hit over should be exhibiting in this building, the head by everything theyve heard let alone in this section, I wandered that day, youve got to do the same over, only to discover that the sound or they wont get the message. So I heard was coming from the open Les substituted a pair of the M K windows of a Pontiac Firebird. There satellites (without subwoofers) and were two men sitting inside the car, the 20/20 tried, with a fair degree apparently talking to each other. I of success, to restore the missing dont know how they were doing it, low bass and smooth out the upper because the level was just about midrange. right for disco where I was, fifteen feet away from the vehicle. I had The most elaborately staged my peak-reading sound level meter demo I heard was also at the Inn: the with me but discovered that it had Infinity Reference Standard, or IRS been left on, its batteries were (they werent able to resist the dead, and there was no AC within 20 obvious pun; the final words on the feet of the car. Anyhow, it was LOUD. opening announcement tape were "... ladies and gentlemen, you II. McCORMICK INN are about to audit the IRS"). The demonstrations were staged for about Across a sunken expressway from forty people at a time and were given the Place is the McCormick Inn. Ex- in two parts: a series of excerpts hibits at the Inn were devoted to of analog tapes, then a playback of audio, and it was here that I heard digital tapes from a Soundstream the KEF 105s (they sounded good), the recorder. The digital tapes (mainly Sony APM monitor speakers (4-way, with Telarc masters) sounded much the square flat drivers, good-sounding, better of the two, apparently because very analytical, $14,000/pair), and of differences in mikes and miking. several satellite/subwoofer combina- As far as I could tell from having tions (ADS, good; ADC, especially heard the disc versions of the Sound- nice; Visonik, not good). Of course stream tapes, the IRS has an overall these evaluations should be regarded character similar to, but smoother

22 than, Infinitys smaller Reference seem to feel a little freer about run- Standard 4.5, that is to say, with ning their priestly number on their huge deep bass, recessed lower mid- visitors here than at AES, where the range, and a forward and slightly visitor is more likely to have an peaky top end. I have never really engineering background. At the CES liked the sound of Infinitys tweeter one hears technically outrageous the EMIT, and having 72 of them play- claims made with great confidence ing at once doesnt make them sound and verve. As a small example there much better. The system did very is a high-priced interconnecting cable nicely on the cannon fire in the 1812 being sold for use with wide-band Overture, though; the difference in preamps and power amps, which some the sonic character of the various electronic designers (Bedini, for cannon shots was quite obvious. instance) swear by. This cable has an RF filter built into one end, and III. THE PICK CONGRESS its manufacturer logically suggests The hotel that housed all the that the end with the filter should high-end manufacturers is a couple of be connected to the input of the miles from the other two facilities, amp so that it will filter out any which gives the smaller exhibitors RFI picked up by the cable itself as space for themselves but separates well as the RFI being passed on from them to a degree that demands care- further up the signal path. In the ful planning about what to see and minds of many, however, this sugges- when. There are shuttle buses that tion becomes a pronouncement that the run from one place to the other, but cable sounds right only when the sig- they also go to many other hotels nal goes through it in the proper on the same route, so its not the direction, as though the wire were quick trip the organizers would have somehow sensitive to the direction you believe. The only way to get of electron flow through it or some- thing. rapid access to the different parts If you point out to a true of the Show is to blow huge amounts believer that the signal in the wire of money on taxis, which are scarce is AC and so flows in both directions, at most times of the day. Its really you may be branded a techno-freak, a very clumsy arrangement, but there which in this case is defined as seems to be no other choice because someone who thinks in abstractions the main convention facilities are all the time and doesnt know how just too far from everything else. to listen. (The only consolation is that it used This is not to say that Mr. to be worse, with the small audio Bedini holds this irrational view manufacturers scattered among a dozen of the way these magical cables work, hotels all over town. - PWM) but he made it very clear that any power amplifier had to have a band- The exhibits at the Pick, as well as most at the McCormick. Inn, were width of at least a half MegaHertz fairly easy to move around in. This to sound good, and that these special apparently is a sign that attendance cables definitely sound better than at the Show was down this year. If ordinary ones. As Peter Mitchell, that is the case, I am not looking who overheard Mr. Bedinis lecture forward to coping with. a busy show. from the entrance foyer of the suite, The hotel has two towers which arent pointed out afterward, a wideband connected above the fourth floor, so amplifier would certainly be more the usual scheme for seeing every- likely to benefit from an input cable that suppresses RFI than would thing is to take an elevator to the top of one tower and walk quickly an amp whose response is rolled off down, noting the rooms you want to above 50 kHz or so. In all fairness visit more thoroughly later, and then it must be stated that the sound in do the same for the-other side. As the Bedini room was unusually trans- is usual with such well-conceived parent and clear, althoug I am in- plans, mine went down the tubes al- clined to ascribe this more to a good most immediately as I wandered aim- phono cartridge (Fidelity Research lessly about, being captured first Mk III) and to the smooth and sweet- sounding Sequerra Pyramid ribbon by one exhibit, then another. tweeters than to anything in the There is a quality of sanctity electronics. about many of the proprietors of ex- hibits at the Pick which I have not There was a surprisingly high found at AES conventions. People incidence of good sound at the Show, despite what I had been led to expect

23 about bad listening rooms and noisy Transfer record, the sound had a vivid- environments. I heard a borrowed ness and solidity which was, in my Beveridge System 3 in one suite sound- experience, unique. The sound was ing very good indeed, although Peter not totally uncolored, having what Mitchell mentioned that the ones in sounded like slight roughness in the the Beveridge suite didnt sound as upper presence range, but on the good. Peter wanted to measure the whole it was so natural, unforced, good-sounding ones with the Ivie ana- and unspectacular (in the best sense lyzer, but the person in charge of the of the word) that it was a blessed suite wouldnt permit it, having no- relief from much of what I had been ticed that Peter was wearing a Stereo. hearing all day. I was extremely Review badge, which meant that he was attractive and easy to listen to, inescapably allied with the forces of while also giving a great sense of evil. It was a truly remarkable dis- immediacy -- a rare combination. play of prejudice. (When this indi- The imaging was, I think, largely vidual, working for an amplifier manu- responsible for this; individual facturer, heard about the theory that voices or instruments (or organ pipes) power amps being operated within their each seemed to possess only one loca- voltage and current limitations tend tion in the sound field instead of to sound the same if their frequency being spread out as they are in most responses are identical, he practically systems, including ones with minimal had an apoplectic fit.) There is a cabinet diffraction, dipole radia- strong progability that in a scene like tion patterns, or other features this, if you remain too level-headed designed to improve imaging. And and rational you will be seen as a unlike the electronic image-enhancers troublemaker, someone who is out to I have heard, the highs seem to come spoil the game. In a very real sense, from the same location as the rest its true. Much of what is being sold of the spectrum. As a result the at the high end has an appeal largely brain has one less kind of unreality based on magic, and the prestige of to compensate for, and the experience technical oddity and high price. With- of listening becomes more relaxed out those factors, high-end audio would and effortless. Placement of both be neither as lucrative nor as inter- the listener and the speakers are esting as it is. And as you probably alleged to be extremely critical have noticed, some of the best sound with this system, although I got at the Show was accompanied by the much of the effect from a position most offensive explanations and argu- a couple of feet off-axis on some ments. of the selections. One remarkable demonstration was There were several French speaker accompanied by no explanations of any manufacturers at the Show, from which sort. Peter Moncrieff, the editor/ it was possible to assemble a general publisher of International Audio Re- view of French speaker design which view, has put together a very unusual is narrow-minded almost to the point speaker system which has imaging pro- of vanishing altogether. This is perties that are nothing less than it: French speakers are smooth and startling. The system, called the uncolored, but they lack the low IAR Lab Monitor, consists of two small bass that Americans have come to subwoofer cabinets and two flattish expect; the region from 35 to 50 midrange/tweeter units that look like Hz is about as rolled off in the scaled-down Quad electrostatics, only French designs as it is exaggerated with funny protrusions bulging out in the speakers we tend to like. the grillecloth in several places. I heard the Hill Plasmatronics These panels are placed almost facing speakers for the first. time, and each other, and although Moncrieff talked for a while with Alan Hill. says they work best in many rooms with He was demonstrating the units to only a couple of feet of separation, they were set up about eight feet dealers, so I didnt have time to make any frequency response mea- apart in his small, very live room surements. I wanted to do this, at the Pick. I heard no material with because Hill showed me a curve stored which I was familiar, and Moncrieff in his Ivie (which he said had been played only a few individual cuts of popular discs or short passages from made at the far end of his rather long listening room) that was un- classical records, so once again firm conclusions cant be made. But on usually flat. The speakers didnt sound as bright as other systems several of the selections, and especi- that I have heard when they have ally on a cut from an old Manhattan

24 been equalized to have flat response baby boom had created the phenomenal under similar measurement conditions. surge in hi-fi business in the late It may be, as Hill claims, that ordi- 60s and early 70s, and how the age nary drivers sound bright and harsh group (average 222 years) that buys when EQd to be flat because they have stereo systems is growing up and out such peak response curves and high of this market, so that dealers who distortion due to nonlinearities at want to prosper in the 80s had better the edge of the diaphragm. Further get into -- you guessed it -- video, measurements and listening tests with specifically projection TV with video the Plasmatronics speakers may have to discs and with stereo audio around wait for Hill to come to this area. it. Bernie also pointed out that He says he will do this (and give a .companies that had done well because presentation to the BAS) if the trip of this bump in the population curve can be made to coincide with the es- (Johnson Johnson in the 50s, Levis tablishment of a dealership in the in the 70s) are now pitching to the Boston area; who wants to be a same people as they get older (JJ Plasmatronics dealer? From what I shows football players using baby could hear (again, on unfamiliar and shampoo, while Levi Strauss has ads slightly unpleasant source material) for jeans that begin, "Lets face it, the Plasmatronics speakers are pro- my body isnt the same shape as it misingly unspectacular, with good over- used to be.. ."). It seems pretty all tonal balance and perhaps some clear that audio, which was once the minor frequency-response problems province of a few of us nutball en- around 2 to 3 kHz from the cabinetry thusiasts, and which has been invaded surrounding the plasma arc. They may and transformed in scale by the Jap- well be extraordinarily transparent, anese behemoths, is going to be ,a but as I was hearing a slightly worn- relatively minor part of some new sounding record there was no way for microprocessor-controlled electronic me to tell. phenomenon in the next decade or so. That may produce a commonplace digital- There are more stories about equip- based system which has performance ment, but Ill close with a bit of over- that falls between good and excellent view. The CES is sponsored by the Elec- by present standards, and which costs tronic Industries Association and is only a few hundred 1990 dollars. therefore basically a massive promotion Almost everyone will have one of and pep talk for the industry. As a these, and then us nutball enthusiasts piece of PR it is immense, and it gives may be left alone again to explore the an idea of the size of the whole enter- outer reaches of the technology the prise which you cant get any other way we were in 19`58, minus our youth way. There are two daily publications and our innocence. covering events and promotions at the Show, one a tabloid on newsprint about the thickness of the new Real Paper, and the other a slick 82 x 11 magazine whose Sunday issue hit 274 pages. The newspaper even has a section of inter- national news from Reuters for those BRIEF NOTES AND COMMENTS ON THE 1980 who are too busy at the Show to buy SUMMER CES by David J. Wienberg a Chicago daily. The Sunday edition This summers CES was the first of the tabloid carried a front-page Id attended in some 15 years. Being story on the Yamaha B-6 power amp, a used to the Washington D.C. Hi-Fi black truncated pyramid that is said Show, and noting the list of almost to be a direct rip-off of the Carver 1000 exhibitors with expectations M-400. There was outrange in certain of over 60,000 attendees, I was sur- quarters over the publication of the prised at the lack of crowding. Ac- story, which added spice to the inci- cording to one person, over 66,000 dent; the dispute was then under nego- pre-registered and somewhere around tiation and has since been settled 55,000 attended. The lack of crowding (Yamaha is paying licensing fees to was attributed to fewer persons from Carver 1. each dealership attending, and those The EIA honchos at the Show were who came concluded their business downplaying the drop in attendance and and left, spending less time at the telling everyone how healthy the in- Show than was anticipated -- testimony dustry is. Meanwhile Bernie Mitchell, to the state of the economy. formerly of Pioneer, now of Advent, I was overwhelmed by the amount explained to the press how the postwar of money some of the exhibitors spent

25 such as Hitachi, with a free-standing but he was having serious hum and re- exhibit hall of its own within the liability problems with the Audio McCormick Place, two floors high and Research equipment he was using. In 30 or 40 feet on a side. Acutex had the DB Systems room Dave Hadaway was driven a tour bus onto the floor of using his Revox to provide feedback- the exhibit hall in which they exhi- free source material, and it was one bited some of their wares. of the rare rooms to use ROBAC sound absorbing panels on the walls. These As for new products, DBX had a have the form of anechoic-chamber surprise: a microprocessor-controlled absorbing panels, are covered with semi-automatic room equalizer for semi-attractive fabric, come in either $1295, including a matched microphone. 1 x 1 foot or 3 x 5 foot sizes, and cost This item has some compromises to keep under $5 per square foot when bought the price down, such as a single pink in quantity. Their absorption at noise source (thus the two channels low frequencies is limited by thier are correlated), and an inability to modest depth, but at midrange and average its measured curves from high frequencies their absorption several room locations to create an seems to be high. Dave said they averaged room equalization. (Many people have commented on the latter went a long way to alleviate some of the room-caused sonic aberrations. point, so it now appears that by the time the product reaches the stores The Oracle turntable from Incep- it will have the ability to store tion Audio Ltd (Canada) was in use in and average curves measured with several rooms. Its platter mat is several mike positions in the room convex in cross-section, with a peak --- PWM). at the spindle, so a record placed Apt stole the show in terms of on the platter actually wobbles on the raised center. Screwing down civilized sound and an apt product: a large spindle clamp presses the a 1031 pound 2/--inch high integrated amplifier rated at 80 watts continuous record into intimate contact with the soft rubber vibration-damping mat. power per channel but with a dynamic The main suspension resonance seems headroom of 6 dB (320 watts/ch short- to be around 3 Hz, where many BAS term output). Its an engineering tour-de-force but is not expected to members feel it should be. It appears to be worth further investigation. reach the market until early 1981. Apt also had the good sense to use Dolby Labs was doing a lecture/ master tape demo material, played demonstration about the benefits of on a Studer B67 with Dolby A. The Dolby FM and HX, and Harman-Kardon general use of discs at most exhibits, showed a full line of cassette decks at the volume levels at which most with HX, but surprisingly few other were playing their systems, virtually manufacturers were showing Dolby HX guaranteed a large amount of acoustic cassette decks. feedback. I was amused by the fact that I also found civilized sound in Kloss Video was inadvertently located the Allison Acoustics and Boston Acous- next to Advents big exhibit area! tics rooms. Allisons Model Six cube Both projection TV systems looked generated the impression that the laws nice, but while Advent had the lights of physics were being rewritten; this turned down low, Henry Kloss had all little $125 box sounded so good I the room lights turned ON. Advent was thought for a while I was hearing the receiving a video feed from a sat- Allison One, and at moderate loudness ellite receiver set up by Channel One levels the little Six can even work (of Newton MA) outside McCormick with the Electronic Subwoofer. At Place. Advent also had their sound a similar price C$130) Andy Petite room, whose walls consist of stacks introduced his new A70, smaller than of Advent loudspeakers; I guess it the A100 but similar in sound. is becoming a tradition. Peter Snell had a new speaker of Instead of merely listening to most unusual construction; Ill have car stereo gear in a wall display or to leave it to others to explain it. in simulated car environments, how (Perhaps hell bring it to a BAS meet- would you like to sit in a Peugeot, ing.) Its sound left me unimpressed, or a BMW, or an Audi 5000? At CES

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it certainly felt good, and the sound excellent reference manual. The audio was interesting. exhibits in the Pick were spread out throughout the hotel, minimizing the NAD used their 7020 receiver to problem of music in one room inter- drive six loudspeaker pairs simulta- fering with the next rooms demo. neously, including AR-9s, AR-94s, Polk Overall, there was a lot to see and 10s, Boston A200s, the new Dahlquist learn, and the people were marvelous. bookshelf speakers, and ADS 730s. It Im glad I took the opportunity to was certainly impressive to hear a attend, and I plan to go next year. "20 watt" amplifier drive this one- ohm load to quite respectible levels. For those of us who listen to SHOP TALK ex post facto there is a marvelous device from Variable Speech Control Co.; a variable-speed cassette recorder with speech correction elec- tronics operating over a range of 0.8 SELECTED CES HIGHLIGHTS FROM CHICAGO to 2.0 times normal playing speed. You by Peter Mitchell could play a complete SHOP TALK pro- gram in only 45 minutes and still I have written a detailed survey understand it! The speed-compensation of part of the Show for the September electronics can also be used with issue of STEREO REVIEW and a broader other recorders; connect an open- survey of the entire Show for the audio reel deck with a 3-3/4 ips tape of supplement in the Sept. 9 issue of SHOP TALK to the input, play it at the BOSTON PHOENIX. So in these para- 7½ ips, set the cassette decks con- graphs I will concentrate on some of trol to 2.0, punch PLAY and PAUSE, the highlights which especially at- and it really works. The price is $295. tracted my interest. Audio aside, the CES covers a It is obligatory, of course, to multitude of electronics including say something about the $20,000 Infinity microwave ovens, antennas, telephone Reference System. From the first day devices, and all forms of video. For of the Show, the question most often those who travel as much as I, Fuzz- asked when encountering someone in buster was there (and competitors); the hallways was Have You Heard the I didnt ask them about the Road and IRS Yet? To add to its allure the Track expose of their apprently fraud- demo was a 20-minute closed-door affair ulent submission to Road and Tracks and one had to stand in line nearly a radar detector evaluation of a "Super half-hour to get in. While the sound Fuzzbuster" which turned out to be a of the system was impressive, it still Cincinatti Microwave "Escort" packaged was more like hi-fi than like live in a Fuzzbuster case! The Escort still music; in fact it is recognizably tests out head and shoulders above "Infinity" as heard in their RS 4.5, everything else, and mine has more scaled up in sheer peak output capa- than paid for itself: in Connecticutt city - clean and detailed at low and recently it detected a speed trap, high frequencies, with a noticeable while a mass. driver got caught for lack of warmth in the midrange. In speeding, and in another recent 3-hour fact the sound nicely complements the trip identified two speed traps. slightly fat, warm sound of the Telarc digital recordings which were being Progress is marked in electronic chess. TRYOM showed a small compu- played. Of course what sent people terized "Chess Traveler" which handles away breathtaken was the way the system reproduced the cannons in the 1812 en passant and automatic pawn promo- tion, is claimed to be able to beat Overture: with not the slightest sense Chess Challenger 7, and boasts a re-tail price of $75. of strain, and with precise stereo imaging of¢ the various blasts. I asked Jack Renner of Telarc about this; Finally, my uninhibited plaudits he said that he had planned specific to the Consumer Electronics Group stereo placements for the various can- (CEG) of the EIA, who run the CES. non shots, but even he had never heard The shuttle buses among hotels and them reproduced the way he envisioned McCormick Place made traveling pain- them, until now, (Of course the fact less, the directories on each floor that the playback was from a copy of of the Pick made finding exhibits the digital tape, rather than from a easy, CEG personnel were eminently disc, helped a lot. Those cannon shots helpful, and the guidebook is an drive most phono cartridges and tonearms

27 into such frenzied excitation that errors arising from boundary reflections; they do well if they just stay with in his new Type 1 2-way he has applied the groove, without worrying about the Allison principle full-range. Its subtleties such as imaging.) midrange/tweeter dome is nestled in (indeed, bisected by) the intersection The Beveridge. System 3, in the of the front panel and a shallow ramp Beveridge display room, sounded very that rises up from the floor to meet smooth through the midrange, but the front panel, so no out-of-phase rolled off rather rapidly at low quarter-wavelength reflections of the and high frequencies. Upstairs in domes radiation can occur to inter- the JVC "super-A" room another pair fere with its direct radiation,. This of System 3s sounded remarkably results in a startlingly unusual ap- transparent, open, and detailed pearance for the speaker, but its with an airy top and firm, well- sound was quite open and transparent. defined bottom. Take your pick. There were a few other rooms where While everyone else was playing one could hear sound that was truly the latest digitally-mastered recordings musical in character rather than Robert Grodinski was playing a twenty- just good hi-fi. Acoustat, for ex- year old recording of Stokowski con- ample, was making some very natural ducting music of Virgil Thomson, using sound with the Monitor 3 and 4, the his RG Dynamics preamp, power amp, and first Acoustat electrostatics which B W 801 speakers. While this Vanguard dont have built-in hybrid ampli- recording was reputed to be one of the fiers; without the amps the speakers best in its day, it sounded wonderful cost only $825 and $1000 each, res- on this system. pectively. The key is an "interface A number of new turntables made module" with transformers overlapping their first appearance at this show in range, said to make an easy load and drew attention as much for their for conventional amplifiers to drive. unusual appearance and construction as In the Pyramid room Richard Se- for their performance claims. In addi- querra was using an FR Mk 3F cartridge tion to the Oracle these included the to demonstrate his speakers, including Janorhurst JBE Series 3 ($795) with a a new $300 HF-1 ribbon tweeter module base hand-sculpted from a solid block (half the price of his revered T-1 of Welsh slate, plus a black acrylic tweeter) which sounded very sweet platter topped with an array of cir- and clean. In the ACR room the R-T cular aluminum discs instead of a $100 ribbon tweeter also sounded platter mat; the $3000 Lux PD-555 remarkably sweet and musical; it which contains a vacuum pump to suck appears to be the JVC ribbon tweeter. discs (warped or not) into intimate Theyre also using it in a line of contact with its platter (evidently "Apature" (deliberately mis-spelled) this is to be done for a minute or so speakers with dynamic woofers, but before play, and the vacuum pump is the tweeter is clearly the best part. switched off during play so as not to And the most startling demonstration add any unwanted vibration); the Mitsu- of stereo imagery was provided by bishi LT-5V ($450), a belt drive with the IAR Lab Monitor speakers devel- straight-line tracking arm, designed oped by Peter Moncrieff. The preci- to stand on edge vertically on shallow sion, stability, resolution, and shelves together with mini-components; three-dimensionality of their images the Aiwa AP-D50U ($350), designed to provided an ear-opening listening be stacked in the middle of a pile of experience. mini-components, and a startling sight to behold - its a front-loading turn- The new Dahlquist box speakers table which sticks out its platter like play very loud, are remarkably free a tongue to receive a record, then it of cabinet resonances, sound very retracts back into its slot for play; clear and detailed, but my admira- tion for them is entirely intellec- and Micro-Seikis $3500 120-pound RX- 5000 whose platter alone weighs 35 lbs. tual; I didnt enjoy them. ADC was demonstrating their B300 woofer Its a belt-drive, imported by SAE; just to gild the lily SAE set up a modules ($600 each) with B410 satel- sample with a second 84-pound platter/ lites ($185 each) playing the Telarc base assembly next to the first, driven "Firebird" at truly wall-shaking levels and sounding pretty good. by a second belt, so that the first platter functioned as the worlds most Peter Snells well-known Type A 3-way expensive flutter-filtering flywheel. speaker made use of Roy Allisons design principles to avoid response And Marantz is finally bringing over here the exotic "Esotec" cost-no-object

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series of components which they intro- phase of the stereo system, as well as duced at the Tokyo Audio Fair two switchable audio-bandpass filtering. years ago, including a two-armed A nice tool to assist audiophiles who turntable constructed entirely in want to decide for themselves about alternating layers of brass and the audible importance of absolute glass. Meanwhile, with all of the phase and of wideband response. The exotic and costly turntables being signal inverting stage can also be of developed, and with the really use- use when bridging power amplifiers ful innovations which are appearing which lack the appropriate internal in some designs, the turntable which connections and phase inversion. I am looking for is still nowhere to I enjoyed wandering around and be found: a $200 unit with a good observing a lot of projection TV systems arm and with a suspension as good as but I was rather startled (and, as the the AR turntable was twenty years owner of an Advent VideoBeam, dismayed) ago. Correct design need not cost to observe how much crisper and more Mean- more than thoughtless design. detailed the Kloss NovaBeam appeared while, I saw one product which looks to be in comparison with all the others. as if it really will help with the As for the cheap projection systems acoustic feedback problem in most which are simply a lens and mirror used existing turntables: the VPI base, to project the picture off a conventional which combines very high mass with 12-inch Sony screen, I was surprised isolating springs. Its worth a closer to observe that the $500 Fried unit look. was not as dreadful as I expected it I finally heard the Omnisonix to be. Of course it cant compete image enhancer at the Show, and to say with a properly designed three-lens that it sounded awful would be an projection system, but considering its understatement. It was injecting price it really wasnt bad at all. far too much L--minus-R into the com- In video I found two developments posite stereo signal, cancelling the particularly exciting. (1) Panasonic bass and emphasizing the noise and distortion in the recording as well demonstrated their VHD videodisc system as yielding a vague, diffuse image. and made it clear that they intend to I told that to the person running the enter the U.S. with it as a full com- demo in the Omnisonix booth and he petitor. Since the VHD system appears at first glance to combine the picture nodded, admitting that they may later quality and control flexibility of introduce a step-up version whose L-R injection will be user-adjustable. the Magnavision/Pioneer optical system Meanwhile I wonder whether the device with the economical price of the RCA system, it looks as if we can plan for varies from sample to sample, since Hal Rodgers (at Popular Electronics) a prolonged three-way battle for market dominance. and David Ranada have said mildly (2) A new company, American favorable things about the samples Value Systems, held a press conference they have heard. Continuing on the to describe and demonstrate their back- topic of image enhancement, Bob Carver yard.. satellite receiver system which has finally taken our initial advice will retail for around $5000. It in- and split his preamp into three sepa- cludes an antenna in semi-kit form and rate products, with the Sonic Holo- a fully-assembled set of ostensibly graphy circuit in one unit, the Peak high-quality electronics. The pre- Unlimiter and Auto-Correlator in a sentation was incompetently managed, second, and the basic preamp in a but Robert Cooper (the satellite TV third unit. So you can now get the guru) lent his prestige, and by impli- Holography or the Correlator without cation his endorsement, to the pro- having to invest in the entire $870 ceedings. And the system works. C-4000 package. Finally, Joel Cohen"s Sound Concepts IR-2100 image restoration control was on display; its remote-control paddle will make it really convenient to use, but I didnt get a chance to hear it. One more signal processor of sorts deserves special mention; the DB-7 from DB Systems, which provides inversion of the relative phase of the two channels, or the absolute

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