JOURNAL OF THE AUDIO ENGINEERIN6 SOCIETY VOLUME 25 NUMBER 112 JANUARYIFEBRUARY 1977 ARTICLES Impulse Testing and Peak Clipping .........................D. Preis 2 Analysis of Decoupled-Cone Loudspeakers ..........James M. Kates 15 Acoustical Impedance, and the Theory of Horns and of the Phonograph (Reprint) ......................Arthur Gordon Webster 24 PROJECT NOTESIENGINEERING BRIEFS Ambience-Related Transmission Systems .......................... Hans Lauterslager and Peter H. C. Nuyten 29 Instrument Isolation for Multiple Track Recording .......M. Rettinger 34 FORUM Far-Field Placement of Mono Microphones .............James B. Lee 38 DEPARTMENTS Standards Update: IEC Meeting Sound Track ................. 70 Notes, Ottawa Meeting ....... 40 Upcoming Meetings .......... 71 56th Convention Preview ..... 44 News of the Sections ......... 72 56th Technical Sessions ..... 48 Membership Information ...... 74 56th Exhibit Previews ........ 55 Membership Form ............ 79 EDITORIAL STAFF Harry F. Olson Editor Emeritus Robert 0. Fehr Editor Patricia M. Macdonald Managing Editor, Jacqueline Harvey Managing Editor, Journal Special Publications lngeborg Shochmal Copy Editor Joan Phyllis Goldenberg Abbie J. Cohen Editorial Associate Publications Assistant Gerri M. Calamusa Editorial Assistant REVIEW BOARD J. R. Ashley E. J. Foster P. W. Klipsch M. R. Schroeder B. Blesser M. B. Gardner J. H. Kogen R. H. Small R. W. Burhans R. C. Heyser D. S. McCoy 1. B. Thomas M. Camras J. M. Hollywood J. G. McKnight E. L. Torick D. H. Cooper P. Kantrowitz I?.A. Moog D. R. von Recklinghausen J. M. Eargle D. L. Klepper J. T. Mullin J. G. Woodward Journal of the Aud~oEngineerlng Society. Volume 25, No. 112, JanualyFebruaty 1977. Published monthly except JanuatylFebruary and Juy!August when publ~shed bl-monthly. by the Audlo Englneerlng Soc~etyand supplled to all members In good standing. Pubiicat~onand Executive Offices, Lincoin Bullding, 60 East 42nd Street, New York. N Y 10017. Second class postage pald at New York, N Y and at addlllonai ma~llngoffices Subscrlpt~onlo nonmembers. $35.00 domestic. $45 00 forelgn. All materlai published In thls journal IS copyr~ghtedc, 1977 by the Aud~oEnglneerlng Soclety and all rights reserved Inquiries should be sent to the Pubitcat~onsOffices at the address above The "Journal of the Audio Engineering Society" and its cover design have been registered as a trademark In the Unlteci States Patent Office. JOURNAL OF THE AUD10 ENGINEERING SOCIETY AUDIO d ACOUSTICS / APPLICATIONS VOLUME 25 NUMBER 3 MARCH 1977 ARTICLES Fast Room Acoustic Analyzer (FRA) Using Public Telephone Line and Computer T. Ken Matsudaira, Tadasni Takise, Keisuke Sekiguchi, and Osarnu Yamaguchi ................................................... 92 A Dynamic Noise Reducer for Sum-Difference Multiplex Systems ................................................Richard C. Cabot 95 PROJECT NOTESIENGINEERING BRIEFS The RCA Quadulator ...................G. A. Bogantz and J. F. 'flells 99 Communication System for a Performing Arts Center ................................ Philip B. Clark and David R. Torrey 106 COMMUNICATIONS Transistors Can Sound Better Than Tubes ..................... Dwight 0. Monteith, Jr,, and Richard R. Flowers 1 16 Comments on "Transistors Can Sound Better Than Tubes" ...............................................Russell 0. Hamm 119 FORUM Comments on "The Use of Fibrous Materials in Loudspeaker Enclosures" ......................................... J. Catrysse 121 Reply to Comments on "The Use of Fibrous Materials in Loudspeaker Enclosures" ....................... L. J. S. Bradbury 122 Teaching the Physics of Hi-Fidelity (Reprint) Kenneth W. Johnson, Willard W. Walker, Raiph Harper, and Arthur Adams 322 FEATURE Am I Too Loud? (A Symposium on Rock Music and Noise-Induced Hearinghoss) ................................................... 126 DEPARTMENTS Upcoming Meetings ......... 151 Shopping the Audio Market .. 159 News of the Sections ........ 152 Available Literature ......... 162 Sound Track ................ 156 Membership Information ..... 163 In Memoriam ............... 167 EDITORIAL STAFF Harry F. Olson Editor Emeritus Robert 8.Fehr Editor Patricia M. Macdonald Managing Editor, Jacqueline Harvey Managing Editor, Journal Special Publications lngeborg StocRmal Copy Editor Joan Phyllis Goldenberg Abbie J. Cohen Editorjal Associate Publications Assistant Gerri M. Calamusa Editorial Assistant REVIEW BOARD J. R. Ashley E. J. Foster P. W. Klipsch M. R. Schroeder 8. Blesser M. B. Gardner 9. H. Kogen R. H. Small R. W,Burhans R. C. Heyser D. S. McCoy I. B. Thomas M. Camras J. M. Hollywood 4. G. McKnight E. L. Torick D. H. Cooper P. Kantrowitz R. A. Moog D. R. von Recklinghausen d. M. Eargle D. L. Klepper J. T. Mullin J. G. Woodward Journal of the Aud~o Eng~neer~ngSociety. Volume 25, No 3, March 1977. Published monthly except JanuarylFebruary and .lulylAugust when published bl-monthly, by the Aud~oEngineer~ng Society and supplied to all members ingoodstanding Publication avd Executive Offices, Lincoln Bullding, 60 Easi42na Streel. New York. N.Y !OOl7. Second class postage paid at New York, N Y and at additional mailing offices Subscription to nonmembers. $35.00 domestic. $45.00foreign All rnaterlal published in this journal is copyrighted @ 1977 by the Audio Engineering Society and all rights reserved. Inqutries should be sent to the Publ~cationsOff~ces at the address above. She "Journal of the Audio Engineering Society' and lts cover design have been registered as a trademark In the Unrted States Patent Office. JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO I ACOUSTICS I APPLICATIONS VOLUME 25 NUMBER 4 APRIL 1977 ARTICLES A Method for Measuring Transient Intermodulation Distortion .......................... Eero Leinonen, Matti Otala, and John Curl 170 Slewing Distortion in Digital-to-Analog Conversion .................. .............................................. .Dennis M. Freeman 178 Public Address Systems (A Reprint) .... I. W. Green and J. P. Maxfield 184 PROJECT NOTESIENGINEERING BRIEFS Localization of Lateral Phantom Sources .... G. Thiele and G. Plenge 196 COMMITTEE CHAIRMEN Moving Sound Image in the Theaters ............... Juhani Borenius 200 Dewitt F. Morris Admissions DEPARTMENTS Review of Acoustical Patents. 204 Sound Track ................ 246 Audio-Past, Present and Future: News of the Sections ........ 250 57th Convention Preview .... 214 Upcoming Meetings ......... 253 57th Exhibit Previews ....... 218 Available Literature ......... 254 57th Convention Exhibitors .. 244 Membership Information ..... 258 EDITORIAL STAFF Harry F. Olson Editor Emeritus Robert 0. Fehr Editor Patricia M. Macdonald Managing Editor, Jacqueline Harvey Managing Editor, Journal Special Publications lngeborg Stochmal Copy Editor Joan Phyllis Goldenberg Abbie J. Cohen Editorial Associate Publications Assistant Gerri M. Calamusa Editorial Assistant REVIEW BOARD J. R. Ashley E. J. Foster P. W. Klipsch M. R. Schroeder B. Blesser M. B. Gardner J. H. Kogen R. H. Small R. W. Burhans R. C. Heyser D. S. McCoy I. B. Thomas M. Camras J. M. Hollywood J. G. McKn'ight E. L Torick D. H. Cooper P. Kantrowitz R. A. Moog D. R. von Recklinghausen J. M. Eargle D. L. Klepper J. T. Mullin J. G. Woodward Journal of the Audio Engineering Society, Volume 25, No. 3, March 1977. Published monthly except JanuaryiFebruary and JulyIAugust when published bi-monthly, by the Audio Engineering Society and supplied to all members in good standing. Publication and Executive Offlces, Lincoln Butldlng, 60 East 42nd Street, New York, N.Y. 10017 Second class postage paid at New York, N.Y. and at additional mall~ngoffices. Subscription to nonmembers, $35.00 domestic; $45.00 foreign. All material published in this journal 1s copyr~ghted@ 1977 by the Audlo Englneerlng Soclety and all rights reserved. lnqulrles should be sent to the Publications Offices at the address above. The "Journal of the Audio Engineering Society" and its cover design have been registered as a trademark In the United States Patent Office. JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO I ACOUSTICS I APPLICATIONS VOLUME 25 NUMBER 5 MAY 1977 ARTICLES Floating-Point Encoding for Transcription of High-Fidelity Audio Sig- nals ............................Francis F. Lee and David Lipschutz 266 Tracing Distortion Correction ........................ E. G. Trendell 273 A Low-Noise High-Output Capacitor Microphone System ............ ....................... .................... Richard S. Burwen 278 PROJECT NOTESIENGINEERING BRIEFS A Novel Approach to Linear Phase Loudspeakers Using Passive Crossover Networks ..............................Erik Bzkgaard 284 Design Problems of High-Level Cone Loudspeakers ................ ................. John R. Gilliom, Paul L. Boliver, and Lucia C. Boliver 294 A Microprocessor-Controlled Digital Waveform Generator ........... .............................................Steven Christiansen 299 FORUM More on Problems of the Sections .....................Bruce Lowell 31 0 DEPARTMENTS Review of Acoustical Patents 312 Sound Track ................ 354 56th Convention Report ..... 316 Shopping the Audio Market .. 355 56th Convention Exhibitors .. 330 Available Literature ......... 359 56th Convention Program ... 332 Membership Information ..... 361 News of the Sections ........ 346 Call for Papers-58th Con- Upcoming Meetings ......... 353 vention, New York, 1977 ... 367 EDITORIAL STAFF Harry F. Olson Editor Emeritus Robert 0. Fehr Editor Patricia M. Macdonald Managing Editor, Jacqueline Harvey Managing