JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS

VOLUME 40 NUMBER 1/2 1992 JANUARY/FEBRUARY CONTENTS PAPERS

Noise Analysis of Transformer-Coupled W. Marshall Leach, Jr. 3 Minimal noise depends on a balance between the transducer resistance ’ innut ansformei parameters, and the noise sources inherent within the amplifying devices The optimizing circuit relationships are derived. Practical may prove bet7er off without a transformer than with one.

Systems On the Nature of Granulation Noise in Uniform Quantization i Robert C. Maher 12

i ULeWodulattoqs. the quantizing " & ’ ’ * of error that are audibly offensive * °

PERCEVAL: Perceptual Evaluation of the Quality of Audio Signals B. Paillard, P. Mabilleau, S. Morissette, and Joel Soumagne 21 ActommtCrprogram, basedon a model of the inner ear, rates the quality of noise-corrupted in general agreeing with the judgments of human listeners. The goal is an objective test suitablefoi evaluating signal coders.

Heat Dissipation and ..Douglas J. Button 32 >'« « high-power driver and

° • •• ; : . s, > I TXX z?:z »« « combm smt- : - compression, * - LETTERS TO THE EDITOR

Comments on “An Empirical Model for Motor Impedance55 Raymond Beljan 42 Author’s Reply J. R. Wright" 43 Comments on “A Low-Cost End-Fire Acoustic Radiator” R J. Fahy and K. R. Holland 43

STANDARDS AND INFORMATION DOCUMENTS

AES standard for equipment—-Application of connectors, part 1, XLR-type polarity and gender 45 AES Standards Committee News 52

FEATURES

AES 92nd Convention Preview: AES in Vienna ” , .» « V 3 Calendar ... * * M * v ..... 3* , 60

Exhibit Previews \i. MV ...... vv* i . 62

" . if . . . . « » ' Exhibitor List . .... ••• ...... ‘ 3 * •• •> *« * •• AES 93rd Convention, San Francisco, California: Call for Papers 100

DEPARTMENTS

News of the Sections ... 89 3 Membership information M : . .. .. Upcoming Meetings .,..92 in Memoriam •* 399 , Sound Track ;V‘ .93 Sections Contacts Directory AOZ::S- Available Literature 94 AES Conventions and Conferences^ . ...104 \.i

. S fi $: i •. IS;?s: ef JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS

VOLUME 40 NUMBER 3 1992 MARCH . fs- /As. y Y r; t if' K CONTENTS PAPERS

A

AES 3-1992: The Revised Two-Channel Interface •» •«'*:*;.* * •*>-VW<* Robert A. Finger 107: Proposed changes,and their rationale,^ detailed for the revision of AES3-1985. TheQftD Diffractal: A New One- or Two-Dimensional Fractal Sound Diffusor ...... Peter D’Antonio and John Konnert 117 The geometrical concepts of reflection-phase grating and fractal self -similarity combine in a Wide- band acoustical diffusor.The authors review the diffusor and fractal developments leading to this f ^combination. A Design Method for High-Audio-Quality FM Multiplex Encoders A. J. Oliveira . 130 The usual 38-kHz L-R modulator is replaced with a system that generates periodically weighted samples of the L-R signal. Noise and in the resulting multiplex signals are negligible:

ENGINEERING REPORTS

A Comparison of Some Loudness Measures for Loudspeaker Listening Tests Ronald M. Aarts 142 Objective measurements of loudspeaker loudness are compared with those determined by listener adjustment. Measures based on B weighting or on ISO 532B are in best agreement with subjective ' ' ' > 7 "~ . .. * • • results. — "77 7/.. 77-. 7 7 . 7 .. -

STANDARDS AND INFORMATION DOCUMENTS

AES Recommended practice for digital audio engineering—Serial transmission formatfor two-channel linearly represented digital audio data 147 77,,7AES Recommended practice for digital audio engineering—-Format for the user data channel of the AES digital audio interface • 2v; * 166 * AES Standards Committee NewsV.• ... 184

FEATURES

' 1 r-:*?r < AES ith International Conference Preview: Portland, Oregon ..... * * 186 ••*-

Calendar , «V, V i V«% , ...... ^. .s . ” • 187. Program . . . •»•ri 188 Updates and Corrections to Review of Society’s Sustaining Members 207

DEPARTMENTS

News of the Sections ... 7 •* 198 In Memoriam ... ^ - 222 : Upcoming Meetings •K>:.••* . . 205 AES Special Publications .223 Sound Track .r...... •••~ 206 Audio Engineering Society Application - . New Products ;;; 7 » » y» i and Developments .-;2ps 7.7. Instructions.. .. . ivv.*. « iVi .227 •AA -• Available Literature ..... , 7 . 244^ Sections Contacts Directory .. 230 Membership Information ^ 216 AES Conventions and Conferences .232 ^ ...

MSS*;*-' JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS

VOLUME 40 NUMBER 4 1992 APRIL CONTENTS PAPERS

Dynamic, Model-Based Linearization of Quantized Digital Pulse-Width Modulation -to Analog Conversion and Digital for Applications in A fundamental- , Power Systems frequency-dependent nonlinearity handicaps M. O.J. Hawksford 235 modulation. A dynamic process uniformly sampled pulse width applications in successfully removes this defect, - DACs and in digital power amplifiers. with possible Neural Network Mapping to Subjective Spectra of Music Sounds Given lengthy training — J. Mourjopoulos and " with samples of music and speech, a D. Tsoukalas 253 evaluates the noise-masking threshold neural network (NN ) subsequently thresholds corresponding to an arbitrary music are estimated more rapidly with the NN signal. Masking If than with analytic methods. The Application of Digital Signal Processing to Large Scale " !ii': Simulation of Frequency ResponseModeling and Optimization - Room Acoustics.^ 8 . Software for a , >....••<•...... Multichannel DSP Engine •5 k..., . : ...... !f The Archimedes . project, inorder to simulate real room Knud Bsnk Christensen 260 pf; of processed reflections, requires ki"- signals with multiple anechoic reproduction >!K, ; . If- . isi structure for that purpose. Described here is the digital signal processing

ENGINEERING REPORTS

Headset with Active Noise Reduction System Aheadset provides - for Mobile Applications its wearer with a 30-dB reduction of Volker Bartels 277 attenuated passively ambient noise. Above500 , by earcup design; below 500 Hz, Hz noise is attenuation is due to active feedback. STANDARDS AND INFORMATION DOCUMENTS AES -ALMA Standard test method for audio engineering Measurement of resonance frequency of — the lowest AES Standards Committee News v 283 :*v* 290 FEATURlS

1992 Directory of Educational Programs Updates *.* and Corrections to 1991/1992 298 Bylaws: International Sections Directory Audio Engineering Society, Inc 328 •rh. *•t 346 DEPARTMENTS

Review of Acoustical Patents News of the 295 Available Literature Sections « '’4*4?» **,*•- • 328 * » *.< 340

Sound Membership ' Track Informationbe « •«$ .333 -* *** 342 Upcoming Meetings Sections Contacts Directory . . . » . • •*•••• * . 350 New Products and 334 AES Conventions and - Developments .336 Conferences .. 352

L ... Si. JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 40 NUMBERS 1992 MAY

CONTENTS

PAPERS

Quantization and Dither: A Theoretical Survey Stanley P. Lipshitz, Robert A. Wannamaker, and John Vanderkooy 355 Dither is lubricant for the quantizing machine. Statistical study of digital models discloses the characteristics of better dithers. For most practical ( non-subtractive ) dithered systems, a 2-LSB, triangular probability-density dither is an optimal choice.

A New Surround-Stereo-Surround Coding Technique . W. R. Th. Ten Kate, L. M. Van de Kerkhof, and F. F. M. Zijderveld 376 The masking effect allows subsidiary coded data signals to be combined inaudibly with a principal, two-channel audio signal. The recovered data is then used to dematrix the two channels and regen- erate a multichannel surround program.

Determining Noise Criteria for Recording Environments Elizabeth A. Cohen and Louis D. Fielder 384 Sensitive microphones and low-noise recorders now prompt a redefinition of “quiet recording environmentA new method for evaluating background noise is proved in several symphony halls , recording studios, and listening rooms.

ENGINEERING REPORTS

A Linear-Phase Digital Equalizer with Cubic-Spline Frequency Response Paul H. Kraght 403 Several faults of analog equalizers are avoidable in a digital design , but uniform frequency response and freedom from ringing still require compromise. Reasonable choices are illustrated in a working model.

STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News 415

FEATURES

92nd Convention Report 418 Exhibitors 428 Program 431

DEPARTMENTS

Review of Acoustical Patents 416 Membership Information 468 News of the Sections 450 In Memoriam 473 Sound Track 456 AES Special Publications 474 New Products and Developments 458 Sections Contacts Directory 478 Upcoming Meetings 460 AES Conventions and Conferences 480 Available Literature 465 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 40 NUMBER 6 1992 JUNE

CONTENTS

PAPERS

Nonlinear Large-Signal Behavior of Electrodynamic Loudspeakers at Low Frequencies . . Wolfgang Klippel 483 Nonlinear stiffness and Bl product are the dominant sources of large-signal .Analytical predictions agree reasonably withdistortion measurements. Distortion might he reduced with : - nonlinear digital processing.

Analysis-by-Synthesis/Overlap-Add Sinusoidal Modeling Applied to the Analysis and Synthesis of Musical Tones . E. Bryan George and Mark J. T. Smith 497 An automatictechnique for analyzing, synthesizing, and modifyingmusical tones is successful in generating avariety of instrumental tones that are perceptively indistinguishable from thdprigiHMsiEasily modified tone vibrato, glissdndd,;dhd duration,i ; ; , ? are attack^ ^ Full Characterization of Linear Acoustic Networks Based on N-Ports and S Parameters ..C. M. de Blok and R. F. M. van den Brink 517 • Theory and equipment are described for measuring the network parameters of an acoustic N-port. The measurement methods are acoustic analogs of microwave practice.

ENGINEERING REPORTS

Fiber-Optic Connector Considerations for Professional Audio ...... Ronald G. Ajemian 524 The background , specifications, testing, and performance of seven connector types are reviewed. The author recommends two connectors for audio use.

STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News 533

FEATURES

Officers of the AES, 1949-1992 538 An Afternoon With Paul Klipsch 540

DEPARTMENTS

Review of Acoustical Patents. .. 536 Available Literature 557 News of the Sections ...... 544 Membership Information. 561

Sound Track ..549 AES Special Publications ••v* 562 Upcoming Meetings ...... 550 Sections Contacts Directory ,...... 566 New Products and Developments ...554 AES Conventions and Conferences 568 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 40 NUMBER 7/8 1992 JULY/AUGUST

CONTENTS

PAPERS

Optimum Reproduction Matrices for Multispeaker Stereo ... Two-channel stereo can be reproduced mpre wlisfectarity with three loudspeakers than with fym. in neraLaisiiig &Mtimhefyffffoudspeakevsgrcaterthan the numberof channels improves the^listening impression , if psychoacoustic effects are properly accommodated. Optimal matrixing provides the reward.

Selection and Training of Subjects for Listening Tests on Sound-Reproducing Equipment

' ' Vk i' *:."iH>.# •...... Soren Bech Design of the listening test and its environment, selection of the test instruments, and the experience and hearing acuity of the listeners may all influence the reproducibility of subjective results. Six tests of loudspeakers with a dozen selected subjects yield the findings discussed here.

Psych©acoustically Optimal Noise Shaping .. •1 » * • ‘ ...Robert A. Wannamaker Noise shaping , with appropriate dither, tames ordinarily conspicuous quantization; noise and redistributes it to frequencies where it is less easily perceived. An improved aural sensitivity function guides design of the noise-shaping filter.

Timbre Solfege: A Course in Technical Listening for Sound Engineers ...... Andrzej Miskiewicz The Chopin Academy of Music offers a course based on extensive technical and ear training. The aim is to develop timbral recognition and memory, analytical sensitivity to timbre-pitch-loudness relationships, and increased skill in other acoustic challenges.

STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News. ..

FEATURES

AES 11th international Conference Report: Portland, Oregon ...

. » * _ » « AES 94thConvention Call for Papers^Berii^ a « - - “ .« * - * -

DEPARTMENTS

Review of Acoustical Patents ... .,/.630 Membership Information.... 661 News of the Sections 6441 AES Annual Report ... ..£663 Upcoming Meetings 649 Audio Engineering Society Application Sound Track 650 Instructions fi 667 New Products and Developments 653 Sections Contacts Directory ...... ,670

# . ; v Available Literature 659 AES Conventions and Conferences V: * - .. .. 672 v:!"” v:<.vl:< =

Srrir JOURNAL OF THE ixh' AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS

VOLUME 40 NUMBER 9 1992 SEPTEMBER CONTENTS PAPERS

•vr The Mirror Filter—A New Basis for Reducing Nonlinear Distortion and Equalization Response

: iPoPf-Vif *': “T:' in Systems v* ..^..Wolfgang KJippel 675 A nonlinear digital filter, adaptively adjusted, forms the heart of a non-feedback system that corrects the nonlinear behavior of the loudspeaker motor, equalizes frequency response, compensated f Doppler distortion, and limits mechanical overdrive.Listening tests confirm the improvement

Hierarchical Transmission System for Multispeaker Stereo ...... Michael A. Gerzon 692 A companion paper ( published in the 1992 JulyfAugust issue) teaches the reproduction, with optimal psychoacoustic effect, of nrchannel stereophonic sound via hf loudspeakers, where n2 >:gf Mere, solutions are found for mixing n7 sources for n2 channels, where n/ > n2 or x\ j < n2, with minimal or no psychoacoustic degradation. ... i .

•* ! ENGINEERING REPORTS

p 1 - Anchor Effect in an Optimum Timbre Adjustment Tomasz R. Letowski 706 In a test that requests listener-adjusted equalizations, listeners tend to prefer a spectrum similar to that of the musical sample first heard. Nevertheless, individual equalization preferences differ

v«'-

.. 'V: fj Hydrophone Techniques for Underwater Sound Pickup . >* * Fred G. GeiL- 711 ; Accurate, stereophonic pickup of underwater sound is attainable. The expected levels of sea noise, and suitable designs of hydrophone, preamplifier, and hydrophone suspension, are discussed.

riir LETTERS TO THE EDITOR rr

Comments on “New Factors in Sound for Cinema and Television” ...... S. F. Wu 719 Author’s Reply .vi Tomlinson Holman 719

* STANDARDS AND INFORMATION ' DOCUMENTS' ' ; ' : f v ‘ . IP Pspprv : Pp % - 'P ,j .; W - v. ^ ” V.. pwp^.iv r -“- v -.L- ? ?? .iPyPPi : - P . AES Standards Committee News 721

M* i FEATURES ‘P& few AES 93rd Convention Preview: San Francisco 722 Calendar ..... 726

Exhibitors • «v M V •I t*•* 728

r i • * Exhibit Previews . - •» * > «' 4r» m * *.* */ * 732 - 1 5i M

. • • DEPARTMENTS 1 :v5!l' 3 V - . - Pv

News of the Sections •••• 759 Audio Engineering Society Application • 4>: •* /!« :;. ; T Sound Track 762 Tnstruct»onsS& v *:»•»:"V" V . 767 Upcoming Meetings ’ 763 AES Special x -k ' Publications ..... 770 Available Literature ilm m ! .... :. ..763 Sections Contacts Directory 774 Membership Information . 765 AES Conventions and Conferences 776

: 4 if.

' M %\ S ,* n ! 11 A V: is SM - . sm. " 'H-3! II , :} > ••..• - . ... JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS .... i- D<

VOLUME 40 NUMBER 10 <'wi" 1992 OCTOBER

, (,j, . J • #V •• ' .wx*: ' * v V in ' •tv*- *** •r.V ;. .1« ; */’ ' . • .. - : CONTENTS PAPERS

,VV : :&S* yihh“iV" -; r Modulation Transfer Function Measurement with Maxipium-Length Sequences^.r.fjQugias D. Rife 77&.~#s- —

• ! hiassessing the intelligibility of reinforcement, , and other systems, 3 T sound- telecommunication MTF * measurements are relatively immune to the effects of background noise an advantage avertime- delay spectrometry and fast Fourier transform methods. —

Restoration of Old Gramophone Recordings S. V. Vaseghi and R. Frayling-Cork 791

: ?». V Clicks, impulses , and surface noise are erased from old or damaged recordings by operations appropriate* to each defect. Applying the concept of a signal- an noise-coherence lifetime yields superior results in removingwhite noise

The Reproduction of Sound in Auditory Perspective and a Compatible System

.. I* * - s of Stereophony •Fr. Heegaard 802 iSsr ! of M~S stereophony and its realization in microphones , loudspeakers, and broad- ^ Theifpiention : : < .y. " ? — r .* Av iirVf ' : & casting-1 arose independently in the ideas and experiments bfHolger Lauridsen of Denmark. " £****

V

• • : < • •

. • . • •' .. WV. '• . . »* ENGINEERING REPORTS ': * * - jHT*. «c«! 5 ’ . . 1 : " .' s : ; > • ! I. * ' '. K: * * v > . *-" " .!x‘ J '" - •• . ; . V ' . . • > * * * *' •r. ^ - C' , Microphones and Wind ••v Jorg Wuttke ^ 80a > All w indscreens impair microphone response, but careful windscreen selection can avoid wind noise with minor response degradation. The choice is guided by the differences in sensitivity to wind between omnidirectional and pressure-gradient microphones. : ' -f ' : 3' - 3 :? ’ v'. lv = = : -.iy :?!v' v! : y 1 = ^ • - i.W * ’ • ^* '*' X"’• • f - j".""" LETTERS TO THE EDITOR :x«y

:• •

’ • Comments on “A Simple Theory of Cabinet Edge Diffraction .. V i.....* >.••«. James Porter 818

’ a » : :V Author s Reply .*.• .v. • * John Vanderkooy 818 ' .;>v

--' STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News • *• ••• ...... 820 ' :Vi 3 :, r ^ :< «- - v .4 - : "7 : * y?: ?. ;.. yy - c,,? „...•:••;•• »:••• •? ... ; .K. ' V v : :;r :l: ' :i. ' • - ;.. •*”* . FEATURES r:- . . '

Review of Society’s Sustaining Members. ... » ••» » « ...... 825

• • ’ • » « ** mmm ( III : An Afternoon With Carson Taylor • » ••• • * * * * V** « • i rTT 842 * ' ”,"P- , • • . ' • i ? ’ ' . . . , W » . .. • - i\ > ( ! :»!• ..i-sr ...* !" . - - ' ‘ ' x;. .v ^ . W .. j./ . '^ - i- • .. .'Vf* .. v. ' * Iv , « 4. -.r DEPARTMENTS . —

News of the Sections ...851- Membership Information . . it.' ^ v - : . : ,• v V . • •>« a VJV: Upcoming Meetings< • * * ..w. In Memoriam ...... ••. ••..... 869

»:« WV « » ;v Sound Track »••« *.« * * * ..-...... 858 Sections Contacts Directory:... • :c.870 - V- V- New Products and Developments KC...... 860 AES Conventions and Conferences .... • « * «.*: « :»V .872

. * 863 Available Literature . . * “ :•** •'

: .”

: .. >v! • • : " : ** „ # . ... :**' s *= = ’ " ' - , Hi' .'*. s W .5 f”: ^ iis--’. jj::V iW? •3 r' : A - : :.V ' * *S JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUST!CS/APPL1CATIONS VOLUME 40 NUMBER 11 1992 NOVEMBER CONTENTS

President’s Message

PAPERS

Analytical Design of Biquadratic Filter Sections for Parametric Filters Closed- farm design of biquadratic low-pass, high-pass,or bandpass filters requimsmimmal computation. Filter sections can he cascaded to form adjustable analog or digital equalizers with satisfactory phase responses.&X

Nonuniform Sampling of Audio Signals Robert W. Adams Equally spaced ( Nyquist ) samples are not necessaiy for complete signal reconstruction; a non- uniform (hut repetitively rigid ) sampling sequence can serve as well. A potential application would embed a service function or channel within a primary signal sequence. — r • Perceptual Effects of Synthetic Reverberation on Three-Dimensional Audio Systems _ fBpfjjipd R. Begault 895 _ ( ^ Spoken words, modified by head-related transfer functions and either reverberantly enhanced or anechoiCy are presented binaurally to listeners in tests of source localization and distancing * Reverberation impairs directional accuracies but improves out-of-head perceptions......

ENGINEERING REPORTS

Vintage Professional Loudspeakers: Their Care, Renovation, and Use Todd W. White --- 905 Integrity demands that the consultant presene and maintain his client’s sound-system investment. System performance is more often optimized by careful attention to original equipment than by its wholesale replacement.The author outlines restoration procedures , . ~

LETTERS TO THE EDITOR

Comments on “On the Naturalness of Two-ChannelStereo Sound” James Boyk 917

STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News... it:«'* •W* 918

FEATURES

New AES Officers 1992/1993 .... ••" * * *.* * Microphone Arrays Optimized for Music Recording Wieslaw R. Woszczyk mm AES 4th Australian Regional Convention, Melbourne, Call for Papers.. 952

DEPARTMENTS

non • * «. ? *,*„ V v ••* • * '940 f : r- | V Available Literature . • Review of Acoustical Patents > *i' * flliSS* A” ** * * * News of the Sections ^ 934 Membership Information••- Wi , .•;‘i.•Vi:;-*1949 > • Upcoming Meetings ; ..939 AES Special Publications 954 Sound Track 940 Sections Contacts Directory 958 New Products and Developments 942 AES Conventions and Conferences .... 960 — JOURNAL OF THE AUDIO ENGINEERING SOCIETY s; AUDIO/ACOUSTICS/APPLICATIONS

VOLUME 40 NUMBER 12 1992 DECEMBER

"JZ'T'E*? CONTENTS PAPERS

A Perceptual Audio Quality Measure Based on a Psychoacoustic Sound Representation

s ...John G. Beerends and Jan A. Stemerdink 963 Classic technicalperfptmance measures ( distortion, dynamic range ) may be irrelevant in judging the quality of systems that exploit auditory masking and data compression; More appropriate methods use music as test signals and operate on models of human perception. Among these, the method introduced here corresponds more closely with subjective quality judgments.

} Design Considerations for Loudspeaker Preference Experiments ... :xi .M. Raymond Jason 979 yyfThe author reviews the extensive art of designing loudspeaker listening tests. Definition of the test* K*.:: objective and the validity of statistical assumptions are often slighted. An experUpaflel test design £ ' ' : . ^ would welcomed V v Z . < be generally . ; - 2 -r. - fZ The Directional Scattering Coefficient: Experimental Determination < !? Li ..Peter D’Antonio and John Kdnnert 997 The measured directional backscatter of energy from an acoustical surface defines a scattering coefficient. Its three-dimensional polar description of absorbing, reflecting, diffusing, or diffracting surfaces is especially helpful to the acoustical designer.

ENGINEERING REPORTS

Accelerated Slope Tone Control Equalizers Dennis A. Bohn 1018 By providing , for treble or bass, more rapid boost and attenuation rates, an audio tone control leaves the midband response nearly unaffected by changes in control settings.These results are realized ' ~ , , “ with little sacrifice of uniform phase response. : v / % % - -

STANDARDS AND INFORMATION DOCUMENTS

;A : !" AES Standards Committee News. . ,?* £ . i/Vi a.a a a a v * 1 * * * ** . - • * * . *•? w »s!1" ; •S***".' FEATURES

93rd Convention Report: * * • •V * a :1026 ; :

: : ..«>ia*j» a « a a V.r« vyvi « a 'V '^ « » ; Exhibitors. * •* *. ,v.* * *

; « ; Program,J * *,?**'’ *•* * * .... - T038SS

1992/1993 AESInternational Directory * . - Sections . . 1065 ; • : Call for Awards Nominations., v.... ,;f: i 1087 ^ Call for Nominations for the Board of Governors . 1088

" Bylaws: Audio Engineering Society, Inc. . -*•**'* « *• * **:«* 1091

AES 6th Tokyo Regional Convention, Call for Papers »*»» * V* « > •* "* 1095 :: W 1 :>>£' ; i « y ' Index Volume 40 .. ^ *>'- « ‘ k l lV .s * 4... to ' •• .. : 1101

DEPARTMENTS

of News the Sections * ...... 1077 In Memoriam ... 1089 Sound Tr|0ES AES Special Publications i ::;:::::i 097 Upcoming Meetings ... 1082 Sections Contacts Directory .... SailVS New Products and Developments 1083 AES Conventions and Conferences. 1112 Available Literature .. JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS 1993 JANUARY/FEBRUARY

displacementversti& frequency data: All are superior to a model based' on linear creeps 8*4 Optical Diffraction Methods for Analysis and Control of Pit Geometry on Optical Disks Jan H. T. Pasman v *ii- During the manufacture of an optical disk master, transmission diffraction measurements monitor , pit depth, width, and quality* Theory\ and the production processes are explained ' ' ' " ’ > < ! , , v i > , ‘ > V , V w A I 5- > " ' ' - ##f;q A High-Performance Voltage-Controlled Amplifier Using Positive Feedback Douglas Frey Careful attention to noise and distortion sources, and the use of positive feedback, yield aVCA with 0.01% distortion at 20 dB gain and 100 dB dynamic range.

cW c»K rs id : * ** —* H * fi

mm i*1 ENGINEERING REPORTS "

Low Frequency Options: Design Curves for Vented-Box Loudspeakers...... Roger Gordon Maxwell Given- a driver with QTS between 0.20 and 0.42, vented-box choices producing a zero-ripple low- frequency response are found using the design curves discussed here

!«! Mm STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News;

FEATURES

AES 94th Convention Preview: Berlin 58 Calendar Exhibit Previews:.. 94 Exhibitor List ...... AUif-f- AES 95th Convention, New York: Call for Papers^ 111 DEPARTMENTS

Review of Acoustical Patents Membership Information 106 News of the Sections 109 Upcoming Meetings . ...AU.1 .' .• 100 AES Special Publications.. 114 . . Directory...... 118 :Sound Track v,; . . 101 Sections Contacts Available Literature^ 104 AES Conventions and Conferences ...120

mi-iSiVj'

' » 1!f •.1 4 ’, :) - • . > Kl j >! JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 41 NUMBER 3 1993 MARCH

CONTENTS

PAPERS

Asymmetric All-Pass Crossover Alignments M. O. J. Hawksford 123 > High-pass and low-pass filters of different order combine to yield a composite all-pass response. The author details a crossover set of complexity increasing to third-order high-pass, sixth-order low- pass. An example shows the usefulness of one alignment in a satellite- combination.

The Effect of Head Shape on Spectral Stereo Theory Karsten Bo Rasmussen and Peter MoHer Juhl 135 :T.. , The head-related stereophonic theory of Cooper and Bauck is reworked assuming a non-spherical but axisymmetric head shape. Results include selection of a more appropriate spherical head diameter than is customarily assumed.

Echo Suppression for Loudspeaker-Microphone System Measurements Georg Nfedrist 143 In a reverberant environment, system response measurements are corrupted either by echoes or by the frequency- or time-domain windowing inherent in the measuring process. A procedure based on pole-zero modeling of the measured system aff ords finer frequency resolution and echo suppression.

ENGINEERING REPORTS

A Simple Method for Measuring Loudspeaker Cabinet Impedance F. Fahy 154 A standing-wave tube technique, sparing of equipment , measures the influence of enclosure vents , stuffing , or wall vibration on driver loading.The method is compared with direct measurements of cone velocity and pressures y -

STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News 157

FEATURES

Directions in Digital Audio Broadcasting. Frank Muiler-Romer 158 Updates and Corrections to Review of Society’s Sustaining Members 179

DEPARTMENTS

News of the Sections 174 In Memoriam 190 Sound Track 180 Audio Engineering Society Application Upcoming Meetings 181 Instructions ...... 191 New Products and Developments 182 AES Special Publications 194 Available Literature ...186 Sections Contacts Directory 198 . . 188 AES Conventions and Conferences .....> * 200 /; Membership Information^*

:.i -i

;.A: S:V *V::- • \ JOURNAL OF THE AiiniO ENGINEERING SOCIETY COUSTTCSTAPPUCMIONS AUDIOASI

1993 APRIL VOLUME 41 NUMBER 4 CONTENTS

: :•

PAPERS ... .Jurgen Meyer 203 r

Earl R. Geddes 214

< are flaring.

REPORTS

ENGINEERING •• » i 231 - F.M. van den Brink . ...C. M. de Blok and R.

i.

: : v • 27r

, S -VS : mnaumliy procejd in « » » < T' • • : ; hnofhon * * "* EV fr1--= -

AN,ND INFORMATION DOCUMENTS STANDARDS 248 ...... Committee News Standards ; v : AES V- • . •"

>

: FEATURES : 252 , Denmark Preview: Copenhagen ;:.S ' 253 Conference .. * .• al » V AES 12th internation ' ...... 254 Calendar * 266 ' • • * • » * *’ • * Program Vi« .i• ' * Sections Director, * * * ? 1992*1993 international Updates and Corrections tolo . « ' • if DEPARTMENTS Engineering Society Application ..261 Audio .279 * * of the Sections Instructions ; ..282 > 8 • News v ...2 . •i > :p ' - * ' I • » » . ' •* * Publications Sound Track ...... ’.. • . ^ AES Special 286 }£&&?***<* 271 288 Developments AES ?andConferences NewPrSctfand ...... 274 Contention Available Literature ...... 276 Membership Information JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 41 NUMBER 5 1993 MAY CONTENTS

PAPERS # * Toward the 24 bit - DAC: Novel Noise-Shaping Topologies Incorporating Correction for the Nonlinearity in a PWM Output Stage ... The nonlinearity Peter Craven 291 inherent in a conventional pulse-width-modulation digital to corrected with a nonlinear - -analog converter is noise shaper. Simulation demonstrates 26-hit performance. Designing analog hardware of complementary quality will prove challenging.

Distortion Immunity of MLS-Derived Impulse Response Measurements Chris Dunn and Malcolm Maximum-length-sequence — Omar Hawksford 314 measurements, optimally applied, surpass periodic-impulse testing in their immunity to error An elaboration of the technique is completely immune to even-order distortion in the test device.777 ~ 7 - = /- • » - ' 777 77: * Methods for Multiple Wavetable Synthesis of Musical Instrument Tones 77 ..Andrew Horner, James Beauchamp, and Musical or vocalsounds Lippold Haken 336 are synthesized by adding several fixed spectra ( wavetables) whose amplitudes varywithtime.The problem is choosing the fixed spectra and variably blending them for a best match with the original sound.Two methods for doing so succeed here.—-^ ^ ENGINEERING REPORTS Real-Time Implementation of Asymmetrical Frequency-Modulation Synthesis Asymmetric B. T. G. Tan and S. L. Gan ' 357 frequency modulation, alone or in combination with conventional improves the FM, eases and \ FM synthesis of musical waveforms.The technique is verified in real computer signal processor time with a

LETTERS TO THE EDITOR Comments on “Efficient Filter Design for Loudspeaker Equalization” J. Mourjopoulos Authors’ Reply 364 Richard Greenfield and Malcolm Omar Hawksford 365

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News h .. .> 367 Erratum to AES18-1992 367 FEATURES

94th Convention Report riv.:. 370 Exhibitors .177.17; w .. VV:» i ' V ... .. • •.. .. 380 7 Program.,. ^ 385 DEPARTMENTS

News of the Sections . .412 7: Available Literature Sound ..... v.V 426 Track . .421 . Membership Information 427 Upcoming Meetings ... 422 Sections Contacts Directory 430 New Products and Developments 424 AES Conventions and Conferences 432

m m- JOURNAL OF THE a< AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS

1993 JUNE

< One might suppose—viewing the span of time in which acoustical horns have found use in musical instruments, hearing aids, ,loudspeakers-rrikat horntheory had become settled,complete, well understood, and an easy guide in the desigrtef new applications. But this isnot so.Uncertain

* , ‘ Every One-Parameter Acoustic Field Obeys WebstefciBorn Equation.. " * Gavift R Putiandr r 435 I Z Webster’s argument for his horn equation is puzzling , but itis not restricted to plane waves, as some ' , have inferred. Wave fronts of two other geometries issue exactly from, it.Perhaps disappointingly, there are not more. : :

AcousIftpYaveguideTheory Revisited.. Earl R. Geddes 452 id- Wave propagation in a horn is calculated exactly using the wave equation rather thanWebster’s. f :. B e h a v i o r of the oblate spheroidal waveguide is one example. Higher order modes,ppf(revealed by ' Webster’s equation, have predictable,cutoff frequencies. _

Acoustic Waveguides—In Practice ..Paul D. Bauman, A, B. Adamson, and Earl R;Geddes 462 The primary purpose of a horn is to control directivity. Fora given mouth area, throat area, and length, variation of the horn contour yields nearly trivial differences in response,despite differences in driver loading. Acoustic waveguides ( oblate spheroidal horns) demonstrate stable coverage, smooth response,and low incoherence. 4 I •

Horn Modeling with Conical and Cylindrical Transmission-Line Elements .;. .Dan Mapes-Riordan ' 471 :3;:

; In simulating horns and ducts, transmission-line modeling is intermediate to lumped-parametgfjmdy finite-element modeling in accuracy and computingdifficulty.Of the modeling elements considered, the lossless conical mubest compromise between speed arid accuracy: Examples are shown:

The Boundary-Element Method and Horn Design;..... D. J. Henwood 485 The acoustic field generated by a vibrating surface of arbitrary shape is calculated by the boundary* element method, cousin to the finite-element method.Theauthor summarizes the mathematics and computation, illustrating their use in design qfdJmaU horn :

<• STANDARDS AND INFORMATION DOCUMENTS * AES Standards Committee News:." 497

5

Officers of the AES, 1949-1993... s:: . * 503 ? f *?: \'\u ' j;...it : DEPARTMENTS

, Review of Acoustical Patents. .. . 499 Available Literature v* • ...... i. 524

• :K News of the Sections 504 Membership information. • .

, . .. . « * . * * Sound Track ...... :516 AES Special Publications !> 530 Kiaij.'ii-iV - ' Upcoming Meetings . * * i'S'i: . ,518 .. , s•• • • * .. Sections Contacts JL.. ;; ' New Products and Developments...... 520 AES Conventions and Conferences . .•a.'

H •ji: « . T ' i - 5 :y:

• > * it nftM* JOURNAL OF THE

AUDIO ENGINEERING SOCIETY s» r “ ^ AUDIO/ / ACOUSTICS APPLICATIONS jy.iv#

VOLUME 41 NUMBER 7/8 1993 JULY/AUGUST

CONTENTS

PAPERS Theory and VLSI Architectures for Asynchronous Sample-Rate Converters w/ .... . :.2 - ...... Robert Adams and Tom Kwan 539 fAn asynchronous converter accepts digital data at an initial source rate and releases data as requested at a second, arbitrary rate.The asynchronous method developedhere requires no synchronizing of a high-frequency clock, tracks large sample-rate variations, and assembles its functions in a single structureV

A New Approach to Assignable Control-Surface Design Michael Paul Stavrou 556 Careful attention to human factors and the choice of touch-sensitive controls introduce a console design that promotes the engineer's ease and efficiency and reduces fatigue. Console actions are completed with a small fraction of the moves and time consumed by a conventional board.

An Engineering Study of the Four-Multiply Normalized Ladder Filter Dana C. Massie 564 Scaling a proper compromise to avoid either signal overload (overflow ) or excess noise, is a problem in the design of any active filter.This digital filter is more accommodating than others with respect to scaling and noise. An example uses it as a parametric equalizer.

A Dual-Channel MLS-Based Test System for Hearing-Aid Characterization T. Schneider and D. G. Jamieson 583 Because of the special automatic gain control characteristics of hearing aids, tailored procedures are needed in measuring their responses. A maximum-length-sequence test method is faster than the standard noise method and requires much less computation.

STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News. i...... n:..; 595

FEATURES

AES 95th Convention Preview: New York .* 602 -i • « . . Calendar •* r» •;*, •si. • ** * * ...... smfafr ...... 004

i .i Exhibitors . •* e’*"•'•'•'a m'w ji 606 ^ Exhibit Previews ,4- 609 AES 96th Convention, Amsterdam: Call for Papers 656

DEPARTMENTS ‘ ' •• . > •" • . Vs? •: •:• V. Sf 1 s r.i-. i- /?",' Review of Acoustical Patents ...598 Membership Information ...... 650 ' jy ' ‘ News of the Sections * •» » * »*" 4...... 640 In Memoriam tfwm $'» 4 L wV ;655 V Sound Track 645 AES Special Publications •»;• 658 Upcoming Meetings * .646 Sections Contacts Directory ...... 662 - s r. .*** Available Literature * • »** * * • ••» 648 , f *- ; * • * - AES Conventions and Conferences 664 ; ; §]•? «sf

is'ii

' ( * Li: « ‘ : : •SH: JsV l It • > - • S./' - ‘ ' i- « -• ¥*• 1. &*•> . f H 4 rfV’- • « • . * :: •. • hi. if. : .i. r. .,, f • .. 6 4 4 .. .. iL yin < " . « ?M &y . # f v'f - f £|3 S * it&S i < »: '.S ' . jr. wi'i; :?.£A > * iEWsta- “ irf.i-V £ '• iv> A»Sr„ . i? K/!' u - • :5^: :,v?K . ‘S' :

•4>Y JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS

VOLUME 41 NUMBER 9 1993 SEPTEMBER

' .•=;•7 ^ CONTENTS

‘4? ' PAPERS v 'i’^ ::: :: V-*

Filter Topologies ... « v; 1 » » ( ,»> *.. T •* • * * Rhonda Wilson 667

Axisymmetric Model of a Moving-Coil Loudspeaker *, •«V Vi.David J,Murphy The familiar low-frequency model of a ported direct radiator is elaborated to account for individual acousticloadings of annular zones of the diaphragm and dusicap, port and box resistances arid compliances, discrete elements of the enclosed air, and diffraction at the enclosure edges.

Moving Boundary Conditions and Nonlinear Propagation as Sources of Nonlinear Distortions

• 1 • in Loudspeakers . rv*'*'* * Mfi * .. i . ...Bronislaw Zoltogorski The loudspeaker Doppler effect is reexamined in light of the additional complication of nonlinear V wave propagation, and the resulting harmonic and intermodulation distortions are evaluated. A pre- distorting signal filter may be useful in preventing distortion from forming.

ENGINEERING REPORTS *f :: filS*' Force Conversion Factors of a Loudspeaker Driver it ...... A.N. Thiele 701 A loudspeaker's electroacoustic efficiency is shown equal to the squared product of two force factors, each defined by the measured driver parameters. Their form clearly exposes the designer's alterna- ' ' ' ' •• •' r ' ' \ "' : . tives in choosing a driver and its enclosure. 7 ^ .3, ; fcrl ; ' 3 3 I' -' ^ ’ *4 S' - " ..? LETTERS TO THE EDITOR Comments on “A Linear-Phase Digital Equalizer with Cubic-Spline Frequency Response” ...... Norm Kinnaugh 704 ’ Author s Reply.. * .....v Paul H..Kraght 704 ’ Response to Author s Reply3 .? » *,« « :i‘' ..Norm Kinnaugh 705 ; Comments on “Optimum Reproduction Matrices for Multispeaker Stereo” ...... Hiro Negishi , :’705^3 STANDARDS AND INFORMATION DOCUMENTS

AES S' « . » •• Standards Committee News..... •£** •

FEATURES AES 12th International Conference Report: Copenhagen, Denmark

DEPARTMENTS

Review of Acoustical Patents 712 In Memoriam ...... 745

News of the Sections 722 AES Annual . ,: ,*» V ^ Report * * -*3 746 Upcoming Meetings . , V... 728 tSSidib Engineering Society Application 3 ifT" , !• SoundTracfeS .5 . '"A*'* * * * * 729 Instructions. •” '**;“* .747 " ^ New Products and Developments & Sections Contacts Directory . * Available Literature .737 AES Conventions and Conferences .752 Membership Information 739

. .. . s- - % ! r: ; a/ v' : • ' . 4'r' ^ ?» S . - '. " - •H-

7. JOURNAL OF THE >

AUDIO ENGINEERING SOCIETY * :|#i

AUDIO/ACOUSTICS/APPLICATIONSs

1993 OCTOBER

PAPERS Auditory Distance Perception in Different Rooms The apparent position of a sound source is modified by physical distance, incidence angle, loudness level, and the acoustics of the environment. Listener judgments of source position were gathered in three rooms as the foregoing parameters were varied.

Microphone Arrays for Improving Speech Intelligibility in a Reverberant or Noisy Space 'S. ».« » » • • ••• ...Hiroaki Nomura, Hirpyuki Miyata, and Tammo Houtgast 771 . . ... In noisy or reverberant surroundings, a microphone array captures a speech signal that is more intelligible than that from a single microphone.The sign-to-interference improvement can be measured using the rapid speech transmission index = w

How to Achieve Optimum Performance from Delta—Sigma A/D and D/A Converters

' ' • ; *' : *' •• *•* » • •* •• » •« > •* • » » «,». » ...» « f * « » * » * w v Steven Harris 782 ® ' " •• * ’ • . i **' * - Modern converters “are capable of very highlevelsofperformance f hut the difficulty is in the details of circuit design and hardware layout, all of which must be attended to in avoiding unfore- seen defects. Achecklist of crucial precautions assures success.

. ENGINEERING REPORTS Linear-Phase Digital Audio Tone Control Using Multiplication-Free FIR Filter Yong Lian and Yong Ching Lim digital .requireSanly 24Summing operations per sample, is linear phase andis r -This tone,control - ; ; , arithmetically simpler than the three recently proposed structures with which it is compared.

LETTERS TOTHEEDITOR Comments on “A Computer Model of Binaural Localization for Stereo Imaging Measurement”

' * & > a.If.'i.« . if *> y » ...David Moran **5* *- *'* *

’ ...... V » ' A Author s Reply- **<*** • ..Ewan . Macpherson Further comments on “A Computer Model of Binaural Localization for Stereo Imaging Measurement”.. Mark Davis 797

STANDARDS AND INFORMATION DOCUMENTS :;t. & £ AES Standards Committee News ...... ",1...

FEATURES

Review of Society’s Sustaining Members— •i'Vf ¥> DEPARTMENTS

IS yiiiiii Review of Acoustical Patents... 800 Membership Information k ¥\. News of the Sections IV819 Audio Engineering Society Application lli ' m ~ -JWS Sound Track . *" ,* *'* * .- '•* «Vm .. «.w830 Instructions.... ‘S, s i*r° *• Upcoming Meetings ’ .....832v AES Special Publications 850 .. - , :s New Products and Developments 834 i Sections Contacts Directory ? : ? » ; 854 **** *** ** • 4» Available Literature ...vy-V ..838 AES Conventions and Conferences 858

f iO'fl m S ¥w !• W - W- s’ « !”V i! -8 hi m m¥ iri’W ; « Wifi : r-m JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 41 NUMBER 11 1993 NOVEMBER CONTENTS President’s Message Richard C. Cabot 859 Introduction...... Mendel Kleiner 860 PAPERS

Auralization—An Overview . .. .Mendel Kleiner, Bengt-lnge Dalenback, and Peter Svensson 861 Auralization is a technique that is realizable in several forms.Their history, definition, and limitations are reviewed. Applications of the technique will multiply as appropriate hardware and software improve.

Auralization of Impulse Responses Modeled on the Basis of Ray-Tracing Results.....K.H. Kuttruff 876 Ray-tracing energy data are Converted to an equivalent impulse response which, when binaurcdly ; processed, provides the initial auralization stepffflff ' A Study of the Practicality and Accuracy of Impulse Response Calculations for the Auralization of Sound System Design Akira Mochimaru 881 Impulse response calculations must be sufficiently accurate for design purposes but also practical ' A satisfactory procedure is shown here: ’ - ! , \> ' \ - EARS Auralization Software Wolfgang Ahnert and Rainer Feistel 894 Following earlier software/ this development uses a stored monaural impulse response and directivity data to produce the binaural precursor to auralization. Audibility of Changes in Geometric Shape, Source Directivity, and Absorptive Treatment— Experiments in Auralization .Bengt-lnge Dalenback, Mendel Kleiner, and Peter Svensson 905 Simulated acoustic modifications of three halls and two rooms are tested via auralization for listener reactions. : . • 7 >- Sound-Field Simulator for Room Acoustic Design and Assessment—Introduction of Wave- Theoretical Treatment to Synthesized Sound Takayuki Hidaka 914 Simulated reflections are treated as three groups in sequence, calculated separately by mirror imaging , ray tracing , and impulse convolution. >>- A Sound-Field Simulation System and Its Application to a Seat-Selection System . . Yuji Korenaga and Yoichi Ando 920 A flexible system for computer modeling and auralization is described. One application would choose an auditorium seat for a listener on the basis of his acoustical preferences. r> Application of Binaural Hearing to Scale-Model Testing ...r .. . Keiji Oguchi, Satoru Ikeda, and Minoru Nagata 931 A computer-based system measures the impulse response of a scale-model auditorium. Binaural audition of the impulse response is relatively sensitive to echoes. Auralization in Scale Models: Processing of Impulse Response ' ,.L. .... , Polack, X. Meynial, and V. Grillon 939 In scale models, impulse response measurements must be equalized for transducer responses and compensated for air attenuation and background noise. STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News.....,..., > 946 Sound system network technology: SC-10-1 questionnaire and report.

FEATURES . 6th Regional Convention Report, Tokyo 954 New AES Officers 1993/1994 ...... 963 DEPARTMENTS Review of Acoustical Patents ..>..951 Available Literature 977 News of the Sections ...... 968 Membership Information ...980 Upcoming Meetings 971 Sections Contacts Directory 982 Sound Track 972 AES Conventions and Conferences /.984

New Products and Developments... K* 974 O JOURNAL OF THE A I AUDIO ENGINEERING SOCIETY psm. AboAUDIO/ACOUSTICS/APPLICATIONS 41— 12 1993 DECEMBER VOLUME NUMBER CONTENTS PAPERS Signal-Biased MLS-Based Hearing-Aid Frequency Response Measurement ...... T. Schneider and D. G. Jamieson 987 A signal- processing hearing aid adjusts its gain or frequency response in reaction to its input signal. In consequence, response measurements using noise or pure tones poorly characterize its real be- havior; The difficulty is relieved with a combined bias and maximum-length-sequence test signal. Coherent Demodulation of DSSC without Pilot Tone Using the Amplitude-Locked Loop Archibald M. Pettigrew and Thomas J. Moir 998 A constant-amplitude processor replaces the conventional limiter in a double-sideband, suppressed- - carrier demodulator. Intermodulation and other signal distortions are avoided, and signal recovery “ extends below unity signal-to-noise ratio. / , 7 , , m ENGINEERING REPORTS Characterization of Communications Systems Using a SpeeChlike Test Stimulus M. P.Hollier, Malcolm O. J. Hawksford, and D. R. Guard 1008 The authors define the measurement criteria appropriate for speech systems that are neither linear nor time invariant. A test signal that mimics speech and an analysis based on human perception furnish a method that appears sufficiently accurate to warrant development.

New Playback-Head Azimuth Test Werner Singhoff , 1022

tracks' The track outputs are summed, and the phase pfone « « spec,,0 ,he o,He,The the rmsahgnmmb* *** level difference directly measures azimuth * * - STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News ' ' 1026 Formats for digital audio data interchange; AES3 User Data Channel codes

Jiff ; IPmxmm...... ft*:" *** ...... (insert)

FEATURES 95th Convention Report 1034 Exhibitors 1044 Program 1050

1993/1994 AES International Sections Directory ;5I£; 1072

' * •» < ' CCall for Awards Nominations .f K •• *. » » r •r* 1094 Call for Nominations for the Board of Governors 1095

Bylaws: Audio Engineering Society, Inc...... 7 •** 1102 Volume 41 ^ 1109

DEPARTMENTS

?»;v$ Review of Acoustical Patents loatii Membership Information 1096 News of the Sections 1085 !f In Memoriam 1100 Sound Track 1088 i$j*i i <- • Audio Engineering Society Application Upcoming Meetings 1089 ; 7J ' Instructions 1106 New Products and Developments...... 1090 Sections Contacts Directory ...... 1118 Available Literature. .1092 AES Conventions and Conferences 1120

*? 1 , **m*y & !>' ? < •' ft & • >& § v >&£* •$*:-iViteS.*; »:< r &$*.**A Ml iMii , T ' ! &Zte * y& i j? ' ;« PI

*8: «

: JOURNAL OF THE £

AUDIO ENGINEERING SOCIETY \ AUDIO/ACOUSTICS/APPLICATIONS : : 3.1..*,..

VOLUME 42 NUMBER 1/2 # 1994 JANUARY/FEBRUARY

CONTENTS •#

’ , •: p.n /S.-fWlf President’s Message *'* KjSj$ i§ * ? ji ...Richard G Cabot $ % t* 11 *I flj - mS rr

PAPERS

4 agree

•HIS BB li1 I., Us , ,j, ,, ..‘ ' ’ ’ .. .- , Hfc j IssS * Measuring a Dummy Head in Search of Pinna Cues ..ifSSiliiiilllift H. L. Han E15R The ability to localize a sound source is an incompletely resolved puzzle, but the external ear is clearly important in the process. Dummy^ head-pinna transfer and impulsedMmonse measurements identify spectral features that help to explain prior psychophysical results. - Virtual Imaging Capabilities of Surround Sound Systems ...... X. J. Mac Cabe and D. J. Furlong 38 u imaging performances of three surround sound formats, operating in a live room, are & Horizontal - i' i compared with each other and with iheiocaUzatfjmof a real source. Measurementsof dummy-head interaural time and level differencespx&yide the comparisons.Tfii'ygffrk is aimedtoward an optimal 8. * §&: jo; system for auralizalioh. ; ??$|*

' * ,v * ” , y * r y Z ‘ < '* * * . « , , */* - V* '’' Identification of Loudspeaker Nonlinearities Using the NARMAX Modeling Technique Han-Kee Jang and Kwan 50 f A [ A single set of cone displacement versus input-noise data is used in comparing linear and nonlinear * regressive models of loudspeaker response. A nonlinear model proves superior. Amplitude - frequency response and distortion levels agree with those measured by other means. S&:ij %4 y '•* * < STANDARDS AND INFORMATION DOCUMENTS ;< »1 * 1 j ?? ?S5>“: -- > * ; ' :3'2 •.v*^*^* *4*< 61 Proposed revisions to AES11 synchronization standard; 96th Convention standards meetings schedule

FEATURES

AES 96th Convention Preview: Amsterdam ... 66 Calendar . 68 Exhibitors . 70 Exhibit Previews ..1 jiji 74

' AES Board of Governors Resolution IX T&X.Mtoifar &V m 101 ’•*»«* « >8 ij1i £ | V « A .» AES 97th Convention, San FranciscprCall for P a p e r s. . AVUV ,>UV#4* 107 , ' ^ ~ > > (j * * * ; &it •>•««i; —< ; # >»> < * * ” r si*, r DEPARTMENTS

r»g; aJ v : < +/« * :4 »> •««;4 y«! s. Review of Acoustical Patents $ 62 Available Literature 102 News of the Sections ...... Membership Information 104 - ‘mmm&ms Upcoming Meetings .....i...Rmm Sections Contacts Directory 110 ‘- ‘ ' Sound Track ...... ;..iJife.. . TOO Conventions and Conferences 112

:::

Itf yj* .

: : :: s Si A-! JOURNAL OF THE

AUDIO - , " ENGINEERING. . .. SOCIETY . - . ... . - , .. , - AUDIO/ACOUSTICS/APPLICATIONS

. * list,:l VOLUME 42 NUMBER 3 fit 1994 MARCH

CONTENTSis** PAPERS

A Perceptual Speech-Quality Measure Based on a Psychoacoustic Sound Representation

, John G. Beerends and Jan A. Stemerdink * ’ The psychophysical process in subjectively judging* coder^decoder quality appears to be very different* 7 ’ for music and for speech. The differences require separate choices of tin }e- frequency smearifigartd — level compression in devising quality measures for codecs

Noise: Methods for Estimating Detectability and Threshold J Robert Stuart. & . 124 - . w Elementary signal-to rume measurements poorly assess the perceptual signficancedf noise More elaborate methods, based on extensive background review, are suggested here.

Excess Spacing Loss with Alfenol-Core and Ferrite-Core Magnetic Tape Reproducing Heads

v« « i « • * > • *V’”* ...... John G. (Jay) McjOiight 77 141 ’ - Reproducer spacing loss depends on head wear, tape speed , tape characteristics, and transport g 7 : r " defects.With all of these accounted for, an irreducibleloss may remain, dependent on the head . " ; : materiatl^^STTI < ^ \ 77 -* 77> - 7 7- - \ 7 ENGINEERING REPORTS

On Loudspeaker Cabinet Diffraction .Soren;Rasmussen and Karsten Bo Rasmussen Diffraction measurements using a reciprocity method compare well with calculations taught by Vanderkooy, especiallymfdxis, although off-axis distrepancies are found.

LETTERS TO THE EDITOR

‘..:4b? More on “Dynamic Model-Based Linearization of Quantized Pulse-Width Modulation for Applications in Digital-to-Analog Conversion and Digital Power Amplifier Systems” ; :: M,O. J. Hawksford : • 151

CORRECTIONS

Corrections to “Distortion Immunity of MLS-Derived Impulse Response Measurements”

«j E « a « » « » « » » » » « ...... » » « »»:«• .»•» * • . . • •. •. •* . . • *. DUDn 152

Correction to “An Introduction to Band-Pass Loudspeaker Systems”... * Earl R. Geddes 152 STANDARDS AND INFORMATION DOCUMENTS^

[ AES Standards Committee News f h 153 Guidelines for the use of the AES3 interface *

FEATURES

An Understanding and Implementation of the SCMS Serial Copy Management System for

Digital > Audio. Transmission Clifton W. Sanchez; 162 Updates and Corrections to Review of Society's Sustaining Members 198

DEPARTMENTS ...

t! News of the Sections ...... 189 Membership Information •/« a • 202 ' — Upcoming Meetings * ..* 77192 In Memoriam Sound Track ..;,195 AES Special Publications ....210 New Products and Developmentsg: ,...199 . Sections Contacts Directory ...... ,...214 ; Avaliable Literature ...... :77201 AES Conventions and Conferences >•>/ 7..216

?• rri h W IS JOURNAL OF THE AUDIO ENGINEERING SOCIETY " AUDIO/ACOUSTICS/APPLICATIONS 1994 APRIL

CONTENTS

' •A:?*** t s-HC'C

Aspects of MLS Measuring Systems . John Vanderkooy 219 inamaximumdength-sequenbCmeasuremerit,errors arising from distortion in the system under test do not necessarily subside into a uniformly distributed noise. Indeed,obtrusive distortion artifacts reveal not only the presence of distortion but clues to its character as wellf ' f j ' < _ ‘ ' • • ' „ .=.iwi " / , h' r? 4 v ,, , ; . - - * * - '

:r » V:« Zplzer Roundoff Error Analysis of Digital Filters » •V * '** Mr * v Udo 232 Prior filter structures are compared with a new recursive structure having greater pole density at - low cutoff frequencies.The new structure yields improved petformance withrespect to the deficits of signal and coefficient quantizations:\

Observations on the Audibility of Acoustic Polarity R. A. Greiner and Douglas E. Melton 245 Does acoustic polarity really matter? It matters sometimes, as is shown by the Experiments reported here, although signal characteristics that provoke audible recognition of polarity remain veiled. '' Preserving system polarity is a sensible goal^ yyfyfl • — ENGINEERING REPORTS ^ Microalignment of Drivers via Digital Technology John A. Murray 254 With contemporary test equipment, fine tunings of loudspeaker crossover frequencies, crossover slopes, and other driver alignments are readily made. The author offers a practical w :: ' guide to making them.* " \ V 4 : ^ "' . "

CORRECTIONS

Corrections to “New Playback-Head Azimuth Test,” Werner Singhoff, J. Audio Eng. Soc., vol. 41

« » » « > . i . 264 pp. 1022-1025 (1993 Dec.):. V •*• •* :? .

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News 265 Interface jitter revision; SC-10 meetings; report on AESSC projects

FEATURES

Updates and Corrections to the 1993/1994 International Sections Directory 272

13th International Conference, Dallas, Texas, Announcement.:S:: % 1 274

• » ...... 1994 Directory of Educational Programs V.*.*:* * *!.*•*' * . (Insert)

r i.. ^ ... ,. . > - " .. , DEPARTMENTS

Review of Acoustical Patents ...... 268 In Memoriam ,,^299 News of the Sections 276 Audio Engineering Society Application

' " Sound Track 283 ; Instructions * * * '.. - Vi 301

' New Products and Services 287 AES Special Publications • 4 MMM - ::...304 Upcoming Meetings 288 Sections Contacts Directory .,...309 Available Literature 290 AES Conventions and Conferences ;:r:i312

' .. ,.’9 « 1 . « , 292 Membership Information; .J J. . * * - .. ; .... ? v „ ^ ;:r . .. . V. - . “ / ’ - . . £$

:V; a " 4 •• ‘ if:’^: ^ "!-SS' .if: Cl JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS

VOLUME 42 NUMBER 5 1994 MAY

CONTENTS

' * <, A: • - • • > w A ^ ^ - ‘ * : ••- % 5 ».< > . y, : . ' * •'Sr M \ JA -V . . . • - ... - V! ; «! " ::» : ; '* .<-' i:.vi^:-^i A: X*::«j V pv: !M- > PAPERS ffr'Sfrir' -

Derivation of the Quasi-Butterworth 5 Alignments Joseph J. M. Kreutz and Jorg Panzer 315 QB5 loudspeakerMignments attractively feature relatively small box volumes and cone displace- ments but have been neglected because of analytical difficulties, now dispelled. Design .r /..;w formulas are given in Thiele-Small notation.

Fiber-Optic Transmission and Professional Audio •*..** .«** *«;.*> » •. », > *. .: ..Dan Talbot 325 The opportunities for fiber optics in audio are many and are not limited simply to long-distance transmission. Appropriate optical techniques are new and require careful balancing 4 of electronic circuit device, and signal format tradeoffs. < - . - - :: *' -' » "i * “• * » ^ Noise Reduction by Noise-Adaptive Spectral Magnitude Expansion

« « * * •** r •* *• •»:*...... • • ...... Etter and S Moschytz - . • v . . . ? *'** * •: f * .. Walter George . 341 Noisemlmdmtsystemsm either.om et d mucdlyimahmg specpnlsubtmcdm,ontyvprended :, ^ - ^ ^ involving spectral companding. This paper^explores a noise-adaptive generalization of one-ended systems having some two-ended characteristics.

ENGINEERING REPORTS

A Method for Extrapolation of Missing Digital Audio Data ••ii•-».»« >'viy.•>' Robert C; Maher w 350 Missing or damaged data can be restored by an off-line method that analyzes the signal spectra adjacent to the data gap and reconstructs an acceptable bridge:The method is very effective: ; ’ for concealing gaps shorter than 30 milliseconds. 44.4- - 44444 • 44,44 4444 . 4 - ..If

STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News ...... 358 Correction to SC-10-1 report on network transport systems; AES3 interface jitter reduction " ' .' " . guidelines 4444 44 44 .. 4 : . , : 4;4;4L;:44.444 44 4 . 4 4 4 4 444. 444444 - 4 4 444.4 . 444444

FEATURES

96th Convention Report ••. 370

•

Exhibitors *y y « «.« * » « •*•: ...... » ... * 382 5W” * • ’ Program *» • » ft « «.•V« « •*# « »>* ...... » « » « *» * . 388 'Xo.’ i

;."K: : U : :i = - ^ DEPARTMENTS

Review of Acoustical Patents.., .. i. yi.v..-.367 Upcoming Meetings ..423 News of the Sections w. 411 In Memoriam 424 : ' ' « 1 ' • i t » « § Sound Track .. f' c *• > •» ...... 415 AES Special Publications * J :....42 : 4JS3SK; j-. - New Products and Developments 417 Sections ContactsDirectory ;..429 — : f Available Literature i..ik...... > ....•i..J 4; 419 AES Conventions and Conferences ...432 " { }. : •:: >: V •: A X > -> -i - i.' f Membership information » » * •*:•.* •*• .1: : .. i V a:* : • .- . #« ' 7» • - y :/ - • • • - i • > * jOH j [. " - " • " i - - li ' ’ > i V’V-y A ' JT - . .. • • • - ~ - . . . r •• - - - - = - - - i JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 42 NUMBER 6 1994 JUNE CONTENTS PAPERS

Applications of Blumlein Shuffling to Stereo Microphone Techniques Michael A. Gerzon 435 Blumleins invention of shuffling , little used yet long available, uniquely extends the opportunities i n y f f stereo microphone recording and the quality of stereo loudspeaker reproduction, A simple .i' r - shuffling network is shown. • 22"W' "2 ' 22"*

Anechoic Chamber Walls: Should They Be Resistive or Reactive at Low Frequencies?

••• . D. B. (Don) . Keele, Jr. •• 454 * V ' '* The conventional anechoic room bulks inconveniently large in maintaining its effectiveness at low frequency. In contrast,a spherical or hemispherical chamber, limited in size but with wall impedance appropriately complex, may be effective to as low a frequency as one chooses.

Simulated Free Field Measurements Christopher J. Struck and Steve F. Temme 467 Combining near field and far field measurements forms the basis of a method that finds the equivalent complex free field response of a loudspeaker without recourse to an anechoic room. Harmonic distortion can also be measured .

ENGINEERING REPORTS

High-Performance Total Difference-Frequency Distortion Mete ..Jonathan Scott and Dirk Hetrer 483 Synchronous detection, instead of the usual bandpass voltmeter, and* other design choices enable this manufacturable instrument to measure difference- frequency distortion over a 135-dB range, with odd- and even-order data separately revealed.

LETTERS TO THE EDITOR Comments on “Distortion Immunity of MLS-Derived Impulse Response Measurements” Douglas D. Rife 490 Authors’ Reply Chris Dunn 491 Further Comments Douglas D. Rife 492 Authors’ Reply to Further Comments Chris Dunn 493 Comments on “Horn Modeling with Conical and Cylindrical Transmission-Line Elements” ,...... ;;;V2v,...... I...,..John T. Post and Elmer L. Hixson 497 Author’s Reply Dan Mapes-Riordan 497

STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News 499 SC 10 subcommittee reports

FEATURES

The Musical Restoration of the “Joueuse de Tympanon” D. Mercier,J. Haury, and J.-M. Broussard 506

DEPARTMENTS

Review of Acoustical Patents. 504 in Memoriam •m B ..539 Upcoming Meetings .. . £.^520 Audio Engineering Society Application News of the Sections 2521 instructions » «v "MV. ..54V Sound Track ...:526 AES Special Publications ...... 544 New Products and Developments 528 Sections Contacts Directory ...... 2. 549 Available Literature 2... 531 AES Conventions and Conferences 552

Membership information 534 :V

,4 • rVr .rt& ,/ ' : •• -* f - > ' ' - - • - * .I;: : c = : I - JOURNAL OF THE SOCIETY AUDIOENGINEERING : :W; AUDIO/ACOUSTICS/APPLICATIONS ***** ;:;r

VOLUME 42 NUMBER 7/8 1994 JULY/AUGUST CONTENTS PAPERS Bit-Rate Saving in Multichannel Sound: Using a Band-Limited Channel to Transmit the Center Signal .....S. L. J. D. E. van de Par, W. R. Th. ten Kate, A. Kohlrausch, and A. J. M. Houtsma 555 The object is to reproduce full-bandwidth three-channel sounds without audible loss of quality, " using two full-bandwidth channels and one half-bandwidth (commentary ) channel for * " transmission Several coding options are compared in listening tests. ~ Nontypical Effects in an Electrodynamic Loudspeaker with a Nonhomogeneous Magnetic Field in the Air Gap and Nonlinear Suspensions Andrzej Dobrucki 565 A typical loudspeaker s displacement includes a quasi-constant component whose amplitude and direction depend on drive and frequency: Details of this zero-order distortion reveal the sources and severity of the motors nonlinearities. Possible chaotic behavior is also discussed. i A Clustering Method for Sound Localization Transfer Functions : .Shoji Shimada, Nobuo Hayashi, and Shinji Hayashi 577 , The:signal processing required for successful headphone source localization is subjective andrf - f unique for each listener A proposed teleconference system would allow the listener to select ' ;Mfrmpsi' fuitable transfer function from a prepared seiff ENGINEERING REPORTS

Statistically Significant Poor Performance in Listening Tests Les Leventhal ; 585 Poor test performance may arise from poor test design, technical blunders, or unreliable subjects An episode of worse than random results invites questions in all of these areas. Traveling Microscope Measures Frequency Response of Loudspeakers v...... ; Nagaraj and K. P. Zacharia 588 Peak-to-peak diaphragm displacement versus frequency is measured microscopically and used to predict the loudspeaker’s pressure response.The results closely match the theoretical response '’ ’ j ^ ' for a closed-box system. l * 5 SP f p P% - _ ' « \ STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News , ...... g .i.... 591 Synchronization of digital audio ^ v :: i Draft AES-3ID-xxxx, Draft AES information document for digital audio engineering*—Transmission of AES3 formatted data by unbalanced coaxial cable (insert)

Draft AES-1OID-xxxx, Draft AES information document for digital audio engineering*—Engineering guidelines for the multichannel audio digital interface (MADI) AES10 . .- V (insert) - FEATURES AES 13th International Conference Preview: Dallas, Texas 602 Calendar. 604

, - Program .. : , V W 006 * • ' m •V ^

I th : , « » » « > i-W : “ AES298 Convention, Paris Call for Papers • * * ,S4 4 - .. * 634 '- * * “ *4 AES 5th Australian Regional Convention, Sydney, Australia: Call for Papers . 636 DEPARTMENTS V .’ • • ' \ i- , h. Review of Acoustical Patents ; > ,.. 595 0Membership Information...... ’ . .629 \ * * f - ; A; g$nh News of the. Sections:...., ^617 ^ Audio Engineering Society Application JL-*k Sound Track. ^ .....622 instructions..... rP 638 f ..- . ’ rt - ii Ti Upcoming Meetings w V- .. 624 A|S Special Publications ..... <.. ..641

New Products and Developments f ..626 Sections Contacts Directory ; Vi .645 Available Literature ,628 AES Conventions and Conferences 648 ... .. ' wer. V*r V; : c :X;:!? 0!= r yffi*? :: ^

• i« - :*V * '

iy* v i- JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 42 NUMBER 9 1994 SEPTEMBER

CONTENTS

PAPERS

; :W; Vt- The Effects of Loudspeaker Placement on Listener Preference Ratings : Sean E, Olive, Peter L. Schuck, Sharon L. Sally, and Marc E. Bonneville 651 Room placement offajoudspeaker fneasurahly affects listener judgment of its quality, and some changes in positioning are more easily perceived than the substitution of a different loudspeaker. Placement similarly modifies qualityJudgments of the program materrail Listening tests, uncontrolled for room influences , may be suspect. im t- Audio Amplifiers for Loudspeaker Loads ...Eric B e n j a m i n 6 7 0 In amplifier [design, output-stage power dissipation is a more useful measure than efficiencyJ -* Jl Signal statistics,loudspeaker impedance,and adjustable supply voltageiff , ' , and average dissipation. Practical dissipation limits are found here by experiments with commercial r lQudspee $f s ^ ^ *'* ’ if! 0 ^dJ j w ^ ^ ^ Electroacoustic System Response in a Hall: A Convolution of Impulse Sequences *

t - M Peter Vogel arid Diemer de Vries 6 8 4 The response of a hall sound system is calculated as the convolution of three impulse responses: source-microphone/electronic system, and loudspeaker -listener. As reflections enrich at least t\vq f of these processes, the overallreflection density can be very large. Discussed are the practical consequences for choices in sound .-

Mlrcophone Array for Sound Pickup in Teleconference Systems

V»'« :...Fadi Khalil, Jean Pascal Jullien, and Andre Gilloire 692 A fixed microphone array,its filters fixed and its elements logarithmically spaced , is examined theoretically and by computer simulation. Array directivity is superior to that of a uniform array of equivalent complexity. Experimental results confirm the simulation. .

STANDARDS AND INFORMATION DOCUMENTS ¥ :?v ;s r; 4

, „ - ; : v * « AES Standards Committee News...s..,. .... * > - • •* vs 701 November meeting schedule; control network:,; electromagnetic compatibility; loudspeaker modeling.

FEATURES V

\yiJ y # ? 0 * « AES 97th Convention Preview: San Francisco..... Nik * *- i.Vi

Calenda V 716 Exhibitors 718

C«i r: . Hi & Wi'U m Exhibit Previews .. :

X' DEPARTMENTS ,»i

Review of Acoustical Patents AES Annual Report ;:::..765 ; * ' .... »» «> ~ ’ * News of the Sections .. . v** .' *** /6-Tv Audio Engineering Society Application

.. ,« * ...... Sound Track .** * * - 755 Instructions m . 66

« yi? : mF. Upcoming Meetings .•, . .'.... * * *** i: AES Special Publications t. Jll ' * F ; . « » Available Literature ... ..:..--r760 Section Contacts Directory . > **• , . MembershipInformation ... u:::762 AES Conventions and Conferences . ...»..» «^.vr.776 - - -

58 ' Mi .Sp H * -m. V ft Si mi m * if! ' : m : vi : • ft - V,A * w JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS

VOLUME 42 NUMBER 10 1994 OCTOBER .•! ... CONTENTS

President’s Message Richard C, Cabot 779

A V

PAPERS f;iv ••

The ISO-MPEG-1 Audio: A Generic Standard for Coding of High-Quality Digital Audio ...... Karlheinz Brandenburg and Gerhard Stoll 780 A perceptive audio coding standard, originally proposed for compressed motion-picture audio,is appropriate for other uses: small-computer storage, digital audio broadcasting, multichannel HDTV sound. A range of modes includes subjective quality equal to 16-bit PCM .

A Macroscopic View of Diffuse Reflection .Bengt-lnge Dalenback, Mendel Kleiner, and Peter Svensson 793 Diffuse reflection is first defined,and its properties combined with those of specular reflection— guide an appraisal of computerized reflection models—. Most current models are simplified in ways that can prove unacceptable

Removing Noise from Music Using Local Trigonometric Bases and Wavelet Packets Jonathan Berger, Ronald R. Coifman, and Maxim J. Goldberg sos Several variations of a method for removing noise from faulty recordings demonstrate the method's worth,but there are subjective tradeoffs. The addition Of perceptive criteria and frequency band processing may increase its effectiveness.

ENGINEERING REPORTS

Multichannel Spatial Auditory Display for Speech Communications .Durand R. Begault and Tom Erbe 819 Speech communication is enhanced with a binaural system that places four virtual sources at azimuths of 60 and 90 degrees to left and right of the listener; The system is designed for NASA space launches.

LETTERS TO THE EDITOR

Comments on “On Loudspeaker Cabinet Diffraction” ...... F.J. Fahy 826 Author’s Reply ...... Karsten Bo Rasmussen 826 STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News...... 827 OMFI meeting; status of standards projects

Draft AES20-xxxx, Draft AES recommended practice for professional audio—Subjective evaluation of loudspeakers...... (insert)

FEATURES

Review of Society’s Sustaining Members 832

DEPARTMENTS

Review of Acoustical Patents .829 Membership Information ..866 News of the Sections ...... 854 Audio Engineering Society Application ( ; Sound T r a c k J... * * -858 nstructions. .. 870 Upcoming Meetings 860 AES Special Publications .... 873 New Products and Developments 861 Section Contacts Directory 877

Available Literature ...... ,864 AES Conventions and Conferences ..... 880

••••vC" JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 42 NUMBER 11 1994 NOVEMBER

CONTENTS

President’s Message Louis D. Fielder 883

PAPERS

Digital Equalization of Room Acoustics John N. Mourjopoulos 884 The author reviews the digital principles for equalizing room response.Techniques that approximate the ideal provide a large reduction in the required filter lengths with relative independence of source and receiver positions.

Digital-to-Analog Converter with Low Intersample Transition Distortion and Low Sensitivity to Sample Jitter and Transresistance Amplifier Slew Rate Malcolm Omar Hawksford 901 Reconstructed signal distortions due to clock jitter, induced jitter, and limited slew rate are analyzed as equivalent faults. A system based on multiplying ( product ) converters is less sensitive to these defects. ’ . . . .

Real-Time Implementation of Double Frequency Modulation (DFM) Synthesis B. T. G. Tan, S. L. Gan, S. M. Lim, and S. H. Tang 918 Double FM is an alternative to single-operator FM or asymmetrical FM ( AFM ) in the synthesis of musical tones. A targeted harmonic structure can be produced with fewer computations than AFM requires.

ENGINEERING REPORTS

Acoustical Properties of Air versus Temperature and Pressure Gavin R. Putiand 927 Precise evaluation of a transducer (for example , loudspeaker ) may force attention to the variable effects of atmospheric temperature and pressure.The relevant quantities are accounted for here in a convenient group of consistent formulas.

STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News 934 SC-10-02 meeting ; storage of magnetic and optical media

Draft AES26-XXXX, Draft AES recommended practice for professional audio—Conservation of the polarity of audio signals (insert)

FEATURES

Computer-Controlled Sound Systems Bob Moses 938

New AES Officers 1994/1995 956

DEPARTMENTS

News of the Sections 960 Membership Information 973 Upcoming Meetings 964 AES Special Publications 977 Sound Track 966 Section Contacts Directory 981 New Products and Developments 969 AES Conventions and Conferences 984 Available Literature 971 V SST- ; - . ' -- r * JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS

VOLUME 42 NUMBER 12 1994 DECEMBER

CONTENTS :x - :

Presidents’ Message: Representation of Europe Region Richard 0. Cabot and Louis D. Fielder 987

PAPERS iS* - ?: : Practical Implementation of Low-Frequency Equalization Using Adaptive Digital Filters

» ...... •. ...S. J. Elliott, L. P. Bhatia, F. S. Deghan, A. H. Fu, M. S. Stewart, and D. W, Wilson 988 The low-frequency response of anautomobile interior is equalized experimentally with an adaptive filter. The results illustrate the effectiveness of single-point versus multiple-point equalization and the need for a smooth transition beween low- and high-frequency responses: Perception of Timbre of Reproduced Sound in Small Rooms:Influence of Room and Loudspeaker Position ...... 4- ...... Soren Bech 999 The listening room itself—and the loudspeaker's position within it—both modify the perceived quality of reproduction. Prior observations of these effects are confirmed and extended in the experiments

to - . -. : - described here : .-V;,* On the Directivity of Horn Loudspeakers ...... Tonni Franke Johansen 1008 Unbaffled horn directivities are calculated using a numerical method, with particular emphasis on conical horns. Both axisymmetric and rectangular cross sections are accounted for. ENGINEERING REPORTS An Acoustically Transparent Screen Suemei Fukuhara, Satoshi Kageyama, Yaeko Tat, and Koichi Yoshida 1020 A front-projection video screen with relatively small sound transmission loss can be placed without detriment before the loudspeakers in home-theater or audio-video applications.

LETTER TO THE EDITOR i

Advances in the Application of Acoustics ...... i David Lloyd Kiepper 1024

: >'*“ STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News 1026 Proposed AES3 revisions Draft AES27-XXXX, Draft AES recommended practice for forensic purposes—-Managing ... y.-y--! recorded audio materials intended for examination. (insert)

FEATURES

'' ' 97th Convention Report i-ii 1 « * » « .. ‘A . 1030 =- - r. V i Exhibitors ...... * •* ”...... 1044

Program ...... • •;* * " *'* « 1050 1994/1995 AES International Sections Directory..... 1069 Call for Awards Nominations...... 1092 Call for Nominations for the Board of Governors ...... 1093

.;*ii \ . ' ' Bylaws: Audio Engineering Society, Inc. .. • *: .*• * *- * • 1100 — - ? T

AES 7th Tokyo Regional Convention, Cali for Papers - - * * ii . 1104 AES 99th Convention, New York, Call for Papers ...... 1106 Index to Volume 42 1108

: DEPARTMENTS

' .i' V , News of the Sections * * . .ii 1083 Membership Information....* .. .1094 Sound Track 1086 In Memoriam . .1098 Upcoming Meetings ..... 1088 Section Contacts Directory ...... 1117 New Products and Developments 1089 AES Conventions and Conferences 1120 Available Literature 1091 -

h U ‘ ^W f -?-•*! .:k-

S - l: >, 0 JOURNAL OF THE AUDIO ENGINEERING SOCIETY V < AUDIO/ACOUSTICS/APPLICATIONS

VOLUME 43 NUMBER 1/2 1995 JANUARY/FEBRUARY

fcf .! ' ris:- r U'»j j" • v :• = A*.. CONTENTS

•.

V-i

>siw. : .y * » ». * 4 : PAPERS w f i e . v V . A High-Rate Buried-Data Channel for Audio CD Michael A. Gerzon and Peter G. Craven 3 A novel technique inaudibly diverts several less-significant bits of each CD sample to other uses, without compromise of conventional CD quality or playback. Many applications are proposed for the

.• formed. ' independent channel thus 1 : .. ' ::!,: . ^ I - * >» : • \y ( ' A Variable-Bit-Rate Buried-Data Channel for V-1 try AS}. - ' A.W. J. Oomen, M. E. Groenewegen, R. G. van der Waal, and R. N.J. Veldhuis 25 A variant of the Gerzon-Cravenriiethodexploits masking opportunities with an adaptive noise- shaping filter and adjustable step-size quantizer. Experiments demonstrate a variable bit rate of ' ' > 500 kilobits per second. K r ' Vs>a *v: byJste l W >• Wide-Band and Wide-Dynamic-Range Recording and Reproduction of Digital Audio ...... ;.Mitsuya Komamura 29 A wide-band signal, sampled at 96 kHz, is adapted to DAT ( or CD ) standards by separating the ,,vsignal into high-band data,absorbed by the least significant bit of a 16-bit sample, and low-band ' h»% ’ datathat comprise the remaining 15 bits, < t e y - , " '7>iWy . , : ' ' J " ^* * ‘ -" 5 ! . . \ ** v, —, '" 'H 1 ' ’ • 'S . " •’ ’vSsr * * Formant-Based Audio Synthesis Using Nonlinear Distortion Miller Puckette 40 way of formants in frequency, bandwidth, and amplitude is found i Sound synthesized by controllable A useful for real-time musical applications. The method has been realized in orchestral performance and in experimental synthesis of speech.

( i; : rnyko,. “* • - Viv i kS'. : LETTERS TO THE EDITOR :r< y i •: Comments on "Aspects of MLS Measuring Systems" ...Matthew Wright 48 Author's Reply John Vanderkooy 48

W; ?f &. ifliii:. ‘ ^ : :f V c ' * * "X> ,E - , STANDARDS AND INFORMATION DOCUMENTS "KM " H: S= 5 . O'V; . AES Standards Committee News 50 . 5 98th Convention meetings; OMFI standardization; drafting symbols

V. V' # ;. =S 4 tSSe «. " y . . FEATURES i ” - •• S y Cfli [ #;s ::::<• - 98th Convention Preview:Paris 'iV 54 - Calendar 56 Exhibitors 60

i ; ? ? 64 i »' r Exhibit Previews W * AES 99th Convention, New York, Call for Papers ...... :nyfe 91 '

Information for Authors of Convention Papers... .'.», •*:••*;• *'•« *•* ... £i- 9ST , - fV' . * DEPARTMENTS '."" f < 1 “ News of the Sections ...... Audio Engineering Society Application • ' 00 «' ’li’Wih-v -: 04 : Wfc, ,,, Sound Track .. . Instructions .. v : k - A * ‘ Vjtav, y ;' i ., . : k: : Publications .... -. ;y;4,r; Available Literature .84 AES Special • .' > 9Z ” : Upcoming Meetings .. :!: .85 Section Contacts Directory . .101 Membership Information 86 , AES Conventions and Conferences . 104 In Memoriam 90 n w: WW ?*

Wt ' ‘ V':>r « • .. v: • » ; - •.-a.; X . • ft- 1 ry y~ i-- • l'!- . .

* ;i'-: JOURNAL OF THE AUDIO ENGINEERING SOCIETY / AUDIO/ACOUSTICS/APPLICATIONS VOLUME 43 NUMBER 3 1995 MARCH

CONTENTS

PAPERS Constraints of Filter Banks Used for Perceptual Measurement Thomas Sporer and Karlheinz Brandenburg ,107 The measurement methods developed for evaluating perceptual coding systems all rely on a filter hank. Time and frequency resolutions of several such filters are found inadequate when compared with psychoacoustic requirements.

SPICE Models for Vacuum-Tube Amplifiers ]N. Marshall Leach, Jr. 117 Vacuum-tube amplifier gain, frequency and phase response, transient response, and harmonic distortion are calculated using computer models. A complete power amplifier simulation is shown as an example.

; Efficient Convolution without InputdQutput Delay ..... •*.; William G. Gardner 127 Zero input-output delay convolution results from a combination of direct form filtering and block FFT processing. The method should prove especially useful in real-time applications.

ENGINEERING REPORTS

Twisted-Pair Cables for AES/EBU Digital Audio Signals ...... D. G. Kirby 137 Faultless digital transmission is achievable with twisted-pair cable lengths of several hundred meters if attention is paid to cable quality and equalization.Conventional analog cables are generally unsatisfactory.

LETTERS TO THE EDITOR Comments on “Observations on the Audibility of Acoustic Polarity” John Monforte and Brent Karley 147 Author’s Reply R. A. Greiner 148

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News 150 97th convention reports: SC-02-05 ( synchronization);WG-12 ( forensic audio); and SC-10-01 ( data communications )

FEATURES • .V,: AES 13th International Conference Report; Dallas, Texas, USA 154 Updates to Review of Society’s Sustaining Members 177

DEPARTMENTS

News of the Sections 166 Audio Engineering Society Application Upcoming Meetings 172 instructions 190 Sound Track 175 AES Special Publications 193

New and ; tr « 178 «> Products Developments * V:... . Section Contacts Directory ...197 Vi Available Literature *•;;* * ...182 AES Conventions and Conferences ...200 Membership Information...... '4* * ...184 .

T , V;v. ’-’I ;K JOURNAL OF THE AUDIO ENGINEERING SOCIETY" ' viV AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 43 NUMBER 4 1995 APRIL

CONTENTS

:fi-h- •! *: •:'•*“ tm PAPERS Transfer Characteristics of Headphones Measured on Human Ears ...... Henrik Moller, Dorte Hammershoi, Clemen Boje Jensen, and Michael Friis Sorensen 203 Customary methods for headphone calibration are replaced by one, that measures sound pressure at the ear canal entrance. Responses are found for 40 listeners and 14 headphones. Individual equalizations are preferable for satisfactory binaural reproduction. ^

Design Criteria for Headphones .. Henrik Moller, Clemen Boje Jensen, Dorte Hammershoi, and Michael Friis Sorensen 218 With the techniques of the first paper, experimental results are compared with target responses for V*-\ ' * ' ’ • free- and diffuse-field calibrated headphones. ,

ENGINEERING REPORTS A Perceptual Model Applied to Audio Bit-Rate Reduction C. Colomes, M. Lever, J. B. Rault, and Y. R Dehery 233 An ear model duplicates known hearing phenomena, is useful in masking experiments, and is intended for work in improving perceptual coding. An initial application to an ISO Layer II encoder is discussed.

Brownian Nature of the Time-Base Error in Tape Recordings Robert Prandolini and Miles Moody 241 Analysis of the aperiodic component of tape flutter finds it to be random and uncorrectible. The defect can bear importantly on the precision of analog data logging and the integrity of forensic recordings.

STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News 248 Standards project status; SC -05 interconnections subcommittee report

FEATURES

Hearing Loss & Music Ken Dibble 251 Updates and Corrections to the 1994/1995 AES International Sections Directory 276 Special Supplement to the 1994 Directory of Educational Programs ... (insert) -

DEPARTMENTS

News of the Sections ...... 267 Membership Information ...280 Upcoming Meetings 270 In Memoriam r::.288 Sound Track 272 AES Special Publications 289 New Products and Developments 274 Section Contacts Directory 293 Available Literature 278 AES Conventions and Conferences 296

<—......

' • ::V.: ii f sri- '

.. .. W' !’ . I- - . . . - J;

• ’ ' • i > •» •> •• :. S > . ..-i - ' . !* - v -vv - * *

. I. * *;:

‘: ^. .1 T; iMy. v> ' JOURNAL OF THE AUDIO ENGINEERING SOCIETY ip} AUDIO/ACOUSTICS/APPLICATIONS

VOLUME 43 NUMBER 5 1995 MAY

' C . hi..--- CONTENTS r.;-

iZy.- Kf? 5«:/ : ; Presidents’ Message: Reorganization of Representation of Europe Region ^ tj . « . * Louis D. Fielder and Tim Shelton 299

PAPERS

Head-Related Transfer Functions of Human Subjects sir- Henrik Mailer, MichaelFriis Sorensen, Dorte Hammershoi, and Clemen Boje Jensen 300 Head-related transfer functions of 40 human subjects are measured with source positions distributed over the sphere whose center the subject occupies.Results are aimed at the improvement of the

binaural technique and objectives • other . >

Dynamic-Range Issues in the Modem Digital Audio Environment Ci’.'A s :? * ft if - • ...... • Sv&Sii&i ...... Louis D. Fielder 322 The task of reproducing music without audible noise is challenged by the technical imperfections of microphones, loudspeakers, signal amplifiers, and processors. A required system dynamic range of 122 dB is not usually relaxed by the noisy ambiance of recording venues and listener environments. A Detailed Analysis of a Tima-Dohj ri Formant-CorrectedPitch-Shifting Algorithm

« • . . . * * *, . .* • ^ « ».»«.»<» «.» «•...... «... > «.! .Robert Bristow~Joi[ nson 340 Especially important for vocal tones are pitch-shifting methods that preserve the spectral envelope as the fundamental frequency is altered.Several schemes for doing so are compared in this analysis.

ENGINEERING REPORTS /. ft.;' . •

Evaluating a Measurement SystemK * •' T. Sporer, U. Gbur, J. Herre, and R. Kapust 353 Acoustic masking phenomena are reviewed and guide construction of a measurement system that simulates the perceptive response of the human ear. Masking experiments with the system confirm its usefulnessr

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 364 Paris meetings on sound system control and on synchronization with digital video

V- • FEATURES -T -v;

98th Convention Report .• . 366 Exhibitors . 382 Program..... 388

:y ' : .: .: • \ */1' p U DEPARTMENTS : pi •• i- V -. - • ..-' ‘

News of the Sections.. 404 In Memoriam 420 Upcoming Meetings 406 Audio Engineering Society Application

Sound Track 408 instructions ..,«•.. . ^ 422 New Products and Developments 412 AES Special Publications 425 Available Literature...... ^ -S' - :: 414 Section Contacts Directory ...... 429 Membership Information s* 415 AES Conventions and Conferences ...... 432

;

S.1H ' . - ...I-:. * y- ::

. •' V. /; ;»• • v VV vA - > . ' • A:.,. . "~4 i ~s : • : = , r .-Vf ir. 7A if ' V ?;v - / /. JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS

x.. - v.

VOLUME 43 NUMBER 6 Y w fe; : - M 1995 JUNE \ H U : . hi.:. -v iKU,. . - 1 , W' • , . \ • H Hv ‘ k : CONTENTS X !N =:

:!* Ini '' a.;. v - fj'}: \

f < PAPERS H -i- ' ' ' 77 1 **• Noise Susceptibility in Analog and Digital Signal Processing Systems . Neil A. Muncy 435 Correcting a common defect in equipment design would eliminate many noise problems , and testing for the defect is a simple procedure. Cable shield current in a properly configured system is shown to be a negligible noise source. 4/4. . is: ‘ ' A / 1 « * • HA TK: H: in. -;'Ki ' .“ il: Lines in Systems: Fact, Fiction, and Transformers Bill Whitlock 454 Balanced Audio HI = : Electronically balanced line drivers and receivers are not ideal solutions for problems of induced and common-mode noise. Their behavior is compared with results using transformers.

ENGINEERING REPORTS I ' z.-: H , %) Grounding Systems and Their Implementation Charles Atkinson and Philip Giddings " 465 Building, technical , and equipment grounds are defined in this review of the isolated star grounding system. Minimum ground conductor sizes are listed. r, Considerations in Grounding and Shielding Audio Devices Stephen R. Macatee ; 472 The best of interconnections is balanced cable with a chassis-grounded shield.Careful circuit grounding within the chassis is also important.

An Easily Implemented Procedure for identifying Potential Electromagnetic Compatibility Problems in New Equipment and Existing Systems: The Hummer Test John Windt 484 A 60-Hz transformer and test method inject a test current into equipment shield terminals to identify ij most ' " " those ground circuits susceptible to interferences ^ J \ ; - Automated Test and Measurement of Common Impedance Coupling in Audio System Shield Terminations Cal Perkins 488 Contemporary manufactured cbruit design increases the opportunity for interference byway of >: common shield and circuit grounds. Measurements of these couplings can be automated.

Fundamentals of Grounding, Shielding, and Interconnection Kenneth R. Fause 498 A review of electric and magnetic induction principles introduces discussion and guidelines for the rational and safe design of technical and power mains grounding and equipment interconnection. • v. j,

'4 STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News,.. 517 SC-04 reports on loudspeaker and room modeling r '• K v

: .V Vs ' ' • ,.w ...... i DEPARTMENTS v* i.: = s ' : • News of the Sections 524 In Memoriam 549 Upcoming Meetings .. 532 Audio Engineering Society Application vj Sound Track .. 532i Instructions ” ... V* .550 / - . New Products and Developments...... 534 4 AES Special Publications ..... * 553 K Available Literature . 538 H Sections Contacts Directory --W 557 Membership Information ...n.,... 542 AES Conventions and Conferences 560

' ;. = 7 5 m Sf. • ‘H: - ' • : M : • • • N-X s ‘ i - = 3 ' •. : • » * • W4 - ? ; ' ;, % 1 t.:; Hi . *7 A 'V 4 . '. X": : " - " .! :: !i ; -r SiV..;:. :: -VI: " ft • > -

: & !74K o:- JOURNAL OF THE fi

AUDIO ENGINEERING SOCIETY ,s:. AUDIO/ACOUSTICS/APPLICATIONS

> •2.

V VOLUME 43 NUMBER 7/8 >: 1995 JULY/AUGUST *4 . fi- B .. V*i ^ K > * ^ * V. CONTENTS i

:

• •;

PAPERS T: i ‘‘ v Accurate Model for the Push-Pull Electrostatic Loudspeaker...... Patrick De Visschere , 563 The behavior of the electrostatic loudspeaker is found by synthesizing its electrical, mechanical, and acoustic models.Calculated results are shown for a push-pull,infinite strip diaphragm. " ^ 1=5 1:

i •:v • • On the Acoustic Impedance of Baffled Strip Radiators • - m ' :» » / •V- • m,» a • » * M Stanley P Lipshitz, Tony , and Bruno Salvy 573 Vi: • •** • ... • * - . Q. Scott ^ !«»: , satisfactory, v Theory for computing long, baffled strip radiator has not been \ A - The problem is resolved here, and strip loading is compared with that of a circular piston of equals a* v width.

Constant-Beamwidth One-Octave Bandwidth End-Fire Line Array of Loudspeakers

...... * * • 2.. . ..^Jefferson A. Harrell ...... - * v,v 581 3 / ^ 'tf. The key to constant beanrnuMtymth low side lobes is superposition—of two endfire arrays, supple- ^; mented with signal weighting bf individual elements:Experimental results confirm the procedures 4

1 ENGINEERING REPORTS *

... The Acoustics of St. Thomas Church, Fifth Avenue.;: .^...... igiDavfd Lloyd Klepper j 599 The history of acoustical improvement in the church is reviewed, including equipmentchanges and satisfactory * .tf " * * 1 !{ ' surface to result , . the materials that have led a . * V / ; .? - 7 * i • ;:S, CORRECTIONS 'V Correction to "Fiber-Optic Transmission and Professional Audio” .... DanTalbot 601 •in 'V:t • STANDARDS AND INFORMATION DOCUMENTS ' :- “ r- : *#. :V. ' 1 " :is '

x m AES standard for sound system control—Application protocol for controlling and monitoring - <

' .•i llv. . v 1 .... • ,* . • • 602 , audio systems—Part : architecture * * * ? T " .. - ** * • 1 V - " 614 ' ; AES Standards Committee News ; I I ' 5 New audio file exchange and disk preservation working groups : . X ft ’ ’ ' • • " . . - , , * .. 4: •... . FEATURES *

AES 5th Australian Regional Convention, Melbourne, Australia, Report " * »;** 618

Exhibitors iv, • ...... •t* ... 626

« . fsji. Program •* » « • .. * ... 630 * * * V! ’’Vi * Updates and Corrections to the 1994/1995 AES International Sections Directory •••• 628 v

> 100th Convention, Copenhagen: Call for Papers...... * 656 ;

ft.'‘ ' . V: . DEPARTMENTS : ' > 4:. : r-r Review of Acoustical Patents:... •» •»» 615 Membership Information..., ..649 : < , « News of the Sections ’k 636 .- IftMemoriarii ... *4?* .* ..654 : ?:S - Sound Track . ..V. **h* 643 AWHO Engineering Society Applioetion New Products and Developments 644 - Instructions ...... 658 Available Literature ...... 647 Sections Contacts Directory 661 Upcoming Meetings ...... 648 ?4 AES Conventions and Conferences .....664 74

:w. fii

i JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 43 NUMBER 9 1995 SEPTEMBER

CONTENTS

PAPERS Computer Simulations of Periodically Time-Varying Filters for Acoustic Feedback Control ...... Peter U. Svensson 667 Acoustic system gain-before-instability can be increased using low-frequency phase- or delay- modulators for enhancing reverberation. Several systems are studied by simulation, and experimental results agree well with the calculations.

Timbre Morphing of Sounds with Unequal Numbers of Features ...... Edwin Tellman, Lippold Haken, and Bryan Holloway 678 Morphing combines two or more sounds to form a product having characteristics of the constituents but identifiable as none of them. The process has other uses. Details are given of an algorithm for morphing pitched sounds.

Feedback Linearization of Nonlinear Distortion in Electrodynamic Loudspeakers

... Johan Suykens, Joos Vandewalle, and Johan Van Ginderdeuren 690 The low-frequency, lumped-parameter loudspeaker is shown to be linearizable by feedback for both current and voltage drive. If the loudspeaker parameters are known and time-invariant, then a nonlinear feedback mechanism exists that produces exact linearity.

ENGINEERING REPORTS Mutual Impedance of Circular Pistons H. P. Neff, Jr. 695 The mutual impedance is calculated for circular disks in an infinite plane. Results are valid for disks of unequal size and with any separation. The data are useful in analysis of multidriver loudspeakers.

STANDARDS AND INFORMATION DOCUMENTS AES information document for digital audio engineering — Engineering guidelines for the multichannel audio digital interface (MADI) AES 10 700 AES recommended practice for professional audio — Conservation of the polarity of audio signals 709 AES Standards Committee News 721 99th Convention meetings

FEATURES AES 99th Convention Preview: New York 722 Calendar ...... 724 Exhibitors 726 Exhibit Previews ...... 730 Updates and Corrections to the 1994/1995 AES International Sections Directory 766 100th Convention, Copenhagen: Call for Papers .. 776

DEPARTMENTS News of the Sections 762 AES Annual Report 775 Sound Track ...... 767 Audio Engineering Society Application Upcoming Meetings 768 Instructions ...... 778 Available Literature 769 Sections Contacts Directory 781 Membership Information 770 AES Conventions and Conferences 784 In Memoriam 774 |> 4 j

... JOURNAL OF THE

• ENGINEERING; SOCIETY " • AUDIO • - . . , ; ^ - - - - - / . . = } AUDIO/ACOUSTICS/APPLICATIONS

i

: : 1995 OCTOBER

V;;

. A = . CONTENTS • - sA. •

PAPERS •::: ::r - ^ n X! - - r;A-- “ «*- <* Linearization of Multilevel, Multiwidth Digital PWM with Applications in Digital-to-Analog xf

' Conversion ...... IIV.II. * * *•• ...... Malcolm Omar Hawksford 787 Linearization of PWM encoded signals using multilevel and multiwidth structures is described enabling a parallel (flash) DAC architecture with dynamic linearization. Known nonlinearities can

be reduced to low levels using this technique. y. J

Synthesis of Trumpet Tones Using a Wavetabie and a Dynamic Filter f "A ...... >•...... U. ..Andrew Horner ihd James Beauchamp 799 A method for synthesizing trumpet tones^by storing multiple ^sets of sampled spectral envelopes in a wavetabie combined with a time-varying filter is described. The wavetable-filter combination - produces synthesized trumpet tones with three time-varying functions: spectral centroid, RMS ' ftl'KS' amplitude, and fundamentalfequency. ^ ^’ ' ' • '• ' > : • . « / „ u > : . ,» » . V " -*\ - ' . ' * ' , r. . . . v .. . ' V.. . - An Exact Model of Acoustic Radiation in Enclosed Spaces ... J. R. Wright 813 Acoustic finite-element analysis is used to model sound radiation within enclosed spaceswhile hbwing how to improve the accuracy and reliability of the measurements. ^ f ;

" r ' i V REPORTS . A V •" ENGINEERING - • psf,' V .. u. ." s '* ;;. : ^ ‘ ; : • i . * • Si - : - •A » i \ : . • -XVVA, Filter Morphing of Parametric Equalizers and Shelving Filters for Audio Signal Processing A...... Yinong Ding and David Rossum 821 Morphing ( interpolating ) biquadratic and shelving filter coefficients can be done at speeds up to the sampling rate, and can be accomplished by a few logic gates and a barrel shifter in a VLSI implementation

STANDARDS AND INFORMATION DOCUMENTS AES-3id-1995 AES information document for digital audio engineering — Transmission of AES3 formatted data by unbalanced coaxial cable <.... 827

AES Standards Committee News... **•* * •»*• * * • » w m • «« » > « 845 Project status fist; SC-05 and SC-10 reports

' •i 'r ' FEATURES * - V " 'fs •'I

AES 7th Tokyo Regional Convention, Tokyo, Japan « •* * * * *>;* *» -•* «.• « » •* ...... 852 :i Exhibitors ...... '.* **” 858 Review of Society's Sustaining Members 860 Updates and Corrections to the 1994/1995 AES International Sections Directory . .. 886

VP: "S A :

DEPARTMENTS A;- . - - i l News of the Sections 881 In Memoriam 896 Upcoming Meetings . .884 Audio Engineering Society Application ... • ri Track 885 Instructions -V 898 Sound : M New Products and Developments. > •*»*'«:887 Sections Contacts Directory 901 Available Literature...... 4- 890 AES Conventions and Conferences 904 Membership Information...... 891 :

' S ' i! -’M V

: • : ~ V v : = ¥ : Vi;."-' "'- S JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 43 NUMBER 11 1995 NOVEMBER

CONTENTS

=• President's Message Tim Shelton 907

: • = A->

PAPERS On the Dither Performance of High-Order Digital Equalization for Loudspeaker Systems „ j&.R. G. Greenfield and M. O.J. Hawksford 908 Low-level chaos in infinite impulse response ( HR) digital filters acts as self-dither, decorrelates truncation distortion, and aids linearization of low-level DAC nonlinearity. These characteristics are examined relative to the use of 1IR filters for loudspeaker equalization.

Wavetable Matching Synthesis of Dynamic Instruments with Genetic Algorithms : v...... Andrew Horner 916 A unique genetic algorithm for synthesizing musical instruments reduces wavetable requirements by , . ' ' - , a significant factor over conventional individual wavetable matching. .... v

ENGINEERING REPORTS Evaluation of the “Cocktail-Party Effect” for Multiple Speech Stimuli within a Spatial Auditory Display Kai Crispien and Tasso Ehrenberg 932 A series of computer-generated auditory tests were carried out in a multisource binaural listening environment to evaluate the listeners ability to localize and recognize the test materials within a spatial auditory display. This is part of a program to create an auditory display for vision-impaired computer users. - .

Use of the L. G. Marshall—Crown—Techron ELR Program for Adjusting Digital Units in Sound Reinforcement Systems David Lloyd Klepper 942 A practical method of adjusting and evaluating audio delay systems using computer simulations and commercially available delay equipment to optimize intelligibility is described.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News 946 Low bit-rate coding for AES3

FEATURES New AES Officers 1995/1996 954 Entry and Update Form: AES Directory of Educational Programs 962 6th Regional Convention, Melbourne, Australia: Call for Papers.. 990 101st Convention, Los Angeles: Call for Papers....;...... 992

DEPARTMENTS Review of Acoustical Patents...... 948 Membership Information 982 News of the Sections 966 In Memoriam 988 Sound Track 974 Audio Engineering Society Application Upcoming Meetings 976 T instructions LL.. 994 New Products and Developments 977 Sections Contacts Directory 997 Available Literature 980 AES Conventions and Conferences 1000

- JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 43 NUMBER 12 1995 DECEMBER CONTENT PAPERS Spatial Sound-Field Reproduction by Wave-Field Synthesis . Marinus M. Boone, Edwin N. G. Verheijen, and Peter F. van Tol 1003 Enhanced sound-field systems that use wave-field synthesis in a compatible stereophonic format are explored. Various line-array loudspeaker configurations to approximate wave-field synthesis have been studied and their effects on field distribution shown. Theory supported by measurements illustrates the system's current improved effectiveness.

Perceptual Evaluation of Principal-Component-Based Synthesis of Musical Timbres .. Gregory J. Sandell and William L. Martens 1013 Additive data sets of musical instruments store time-variant representations of musical instrument tones. Principal-component analysis ( PCA) recasts these data into basis vectors, so that a likeness of the original data can be reconstructed. This makes PCA a powerful data reduction tool. When generating nearly identical tones, a 40 to 70% data reduction can be achieved. A unique preprocessing step facilitates natural-sounding time expansion or contraction of synthesized tones.

Distortion Analysis Using SPICE Jonathan Scott and Anthony Parker 1029 Several SPICE-based circuit simulations are compared and their apparent differences discussed. A good understanding of the fast and discrete Fourier transforms can improve postprocessing distortion analysis. ENGINEERING REPORTS Algorithms for Assessing the Subjectivity of Perceptually Weighted Audible Errors — ..M. P. Hollier, M. O. Hawksford, and D. R. Guard * 1041 Conventional engineering performance metrics do not necessarily characterize complex coding and reproduction processes. Concatenating several nonlinear processes in which an inaudible artifact may arise can yield a further audible artifact after subsequent processing. A perceptually weighted algorithm analogous to the human auditory system is used to help predict signal-processor-produced artifacts. STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News 1046 99th Convention acoustical modeling and data networks meetings; Internet proposals

DRAFT AES18-1992 Amendment 1-xxxx, DRAFT Amendment 1 to AES Recommended practice for digital audio engineering — Format for the user data channel of the AES digital audio interface (insert) FEATURES 99th Convention Report 1050 Exhibitors 1068 Program..; . 1072 1995/1996 AES International Sections Directory. 1097 AES News...... 1117 Call for Awards Nominations 1122 Call for Nominations for the Board of Governors 1123 101st Convention, Los Angeles: Call for Papers 1130 Bylaws: Audio Engineering Society, Inc...... 1132 Index to Volume 43 1136 DEPARTMENTS Review of Acoustical Patents...... 1048 Membership Information ...... 1124 News of the Sections.... 1113 In Memoriam 1128 Sound Track 1116 AES Special Publications ...... 1145 Upcoming Meetings 1117 Sections Contacts Directory ...... 1149 New Products and Developments 1118 AES Conventions and Conferences 1152 Available Literature 1120

L JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 44 NUMBER 1/2 1996 JANUARY/FEBRUARY CONTENT PAPERS Automated Parameter Optimization for Double Frequency Modulation Synthesis Using the Genetic Annealing Algorithm ..... B. T. G. Tan and S. M. Urn 3 A novel combination of algorithms has been formulated to achieve greater computational speed and improved wavetable reality. The authors draw upon Boltzmanns rs energy distribution equation to simulate annealing the algorithm's genetic development, and use a genetic algorithm to select the fittest offspring. The computed results indicate the enhanced effectiveness of this approach when compared to the original sound source and other algorithms.

ENGINEERING REPORTS Silicon Microphones Gerhard M. Sessler 16 Tiny silicon microphones have been developed that exhibit good frequency response with low vibration sensitivity. Their diaphragm areas are in the order of 1 square millimeter. Silicon design lends itself to large-scale, low-cost production, since it can use semiconductor manufacturing techniques. It is further proposed that the silicon transducer could be integrated into an associated amplifier. Performance characteristics of several different basic transducing systems are described.

The Sound of Midrange Horns for Studio Monitors ...... Keith R. Holland, Frank J. Fahy, and Philip R. Newell 23 Extensive blind listening tests were performed in a study to identify the perceived sonic characteristics of midrange horn loudspeakers and cone radiators. The study's aim was to find the physical cause for the characteristic sound quality attributed to many midrange horn loudspeakers in studio monitors. The results indicate that the shorter horns sound more alike than the longer horns and tend to be more like the direct-radiating cone reference loudspeaker.

A Time-Frequency Auditory Model Using Wavelet Packets Finn T. Agerkvist 37 Listener-perceived noise in audio coders is examined using wavelet packet analysis with rounded exponential filters and smoothed excitation through windowing. Time-frequency filters that model the human ear functions are emulated to make objective testing feasible, thereby reducing the need for extensive human listening tests to evaluate the noise-masking function. The findings indicate that the current classic masking ratio is much too optimistic. A maximum difference of 7 dB in the time-frequency pattern better represents the masked threshold for different types of maskers.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News 51 High-density CD; presentation reports; AES-lOid erratum DRAFT AES-2id-xxxx, DRAFT AES information document for digital audio engineering — Guidelines for the use of the AES3 interface (insert)

FEATURES Audio Compression for Network Transmission Martin Dietz, Harald Popp, Karlheinz Brandenburg, and Robert Friedrich 58 AES News 82

DEPARTMENTS Review of Acoustical Patents 54 In Memoriam 93 News of the Sections 74 Audio Engineering Society Application Sound Track ...80 Instructions...... 94

Upcoming Meetings 82 AES Special Publications ..f, 97 New Products and Developments 83 Sections Contacts Directory 101 Available Literature 86 AES Conventions and Conferences ...... 104 Membership Information. 88 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 44 NUMBER 3 1996 MARCH

CONTENT

PAPERS Design and Validation of a System for Selecting Optimized Midrange Loudspeaker Diaphragm Profiles G. P. Geaves 107 Midrange axisymmetric loudspeaker diaphragm profile designs are computer generated based on mechanical filter criteria. Mechanical variations are accommodated by a smoothness optimization protocol system that accounts for manufacturing tolerances...... : ; ,

MIDAS-MILAN: An Open Distributed Processing System for Audio Signal Processing ...Ross Kirk and Andy Hunt 119 An open signal processing protocol, which is based on the portability of C software functions, creates a networking system that can be composed of different machine types.This heterogeneous system accommodates different kinds of processors to form a coherent, machine-independent network. .— .r:~ Group Synthesis with Genetic Algorithms Ngai-Man Cheung and Andrew B. Horner 130 Musical sounds can be efficiently synthesized using an automatic genetic algorithm to decompose musical instrument tones into group synthesis parameters. By separating the data into individual matrices, a high degree of data compression with low computational cost is achieved.

ENGINEERING REPORTS

Performance of Cascade and Parallel HR Filters Wei Chen 148 The performance of second-order-section HR filters in digital signal processing applications is materially affected by their configurations. To achieve a signal-to-noise ratio of more than 96 dB, double precision internal states are used together with a parallel form of filter. In general, the parallel IIR filter produces a lower noise figure than its equivalent cascade filter.-

STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News 159 100th Convention meetings

FEATURES

AES 100th Convention Preview: Copenhagen 162 Calendar .. 164 Exhibitors 166 Exhibitor Previews 170 Updates and Corrections to the 1995/1996 AES international Sections Directory 206

DEPARTMENTS

Upcoming Meetings ...... 200 Audio Engineering Society Application News of the Sections 201 Instructions...... 214 Sound Track 205 AES Special Publications 217 Available Literature 207 Sections Contacts Directory 221 Membership Information. 209 AES Conventions and Conferences ..... 224 ’ In Memoriam 213

:«> • •• :* -,yv • • • • <* * • ’ JOURNAL OF THE AUDIO ENGINEERING SOCIETY = * MY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 44 NUMBER 4 1996 APRIL CONTENT

PAPERS A Comparison of Dithered and Chaotic Sigma-Delta Modulators Chris Dunn and Mark Sandler 227 High-order single-bit sigma-delta modulators exhibit low-level artifacts, such as idle tones and noise modulation. This study of high-order sigma-delta modulators compares the trade offs between various dither and chaotic modulator configurations. This is part of an ongoing study to reduce unwanted artifacts in high-order sigma-delta modulators.

Harmonic Balance Method for Estimating the Nonlinear Parameters of Electrodynamic " Loudspeakers •A * .....Hyuk Jeong and Jeong Guon Ih 245 Direct-Radiator r * -* - Harmonic component loudspeaker outputs can be accurately estimated by this unique harmonic balance method.The results of these computations can be used subsequently to develop active compensation circuits to reduce harmonic distortion products from a defined direct-radiator loudspeaker.

r v* <•**. .*•New Method of Characterizing Driver Linearity Scott, Jonathan Kelly, and Glenn Leembruggen 258 A new, simple method for determining nonlinear loudspeaker parameters and correlating the measured findings to loudspeaker harmonic distortion output products is demonstrated. Comparisons of the predicted and measured nonlinear results are very close, and thus present a definitive analytical ./.• 7 tool to aid loudspeaker designers in improving loudspeaker linearity.

!!' : • s • if - • Optimizing the Decay Range in Room Acoustics Measurements using Maximum-Length- Sequence Techniques John S. Bradley 266 Improved room acoustic measurements are made possible by considering some of the influencing parameters while using new computer-based correlation software techniques. Signal correlation can improve the ability of the system to extract low-level reverberant signals from the noise floor, thus enhancing the signal's reverberation time measurement reliability.

STANDARDS AND INFORMATION DOCUMENTS AES27-1996 AES recommended practice for forensic purposes — Managing recorded audio materials intended for examination 274

DRAFT AES22-xxxx, DRAFT Recommended practice for audio preservation and restoration — Storage of polyester-base magnetic tape (insert)

AES Standards Committee News...,. 284 AES27-1996 review; status of projects

FEATURES Audio and MIDI Markup Tools for the World Wide Web Bruce Pennycook 290 Updates and Corrections to the 1995/1996 AES International Sections Directory ...... 303

DEPARTMENTS

Review of Acoustical Patents...... 287 Membership Information 314 News of the Sections 298 Audio Engineering Society Application Sound Tracks...... 305 instructions I...... 317 Upcoming Meetings 308 AES Special Publications 320 New Products and Developments 310 Sections Contacts Directory 324 Available Literature 312 AES Conventions and Conferences 328

! -• = £ : JOURNAL OF THE

AUDIO i ENGINEERING4 SOCIETY '' ** AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 44 NUMBERS 1996 MAY

CONTENT PAPERS Physical Modeling of Plucked String Instruments with Application to Real-Time Sound Synthesis Vesa Valimaki, Jyri Huopaniemi, Matti Karjalainen, and Zoltan Janosy 331 Real-time sound synthesis has been implemented on five plucked string instruments with the view to extending the techniques to similar instruments. Future studies will include modeling other plucked string instruments, a more sophisticated inverse filtering design to account for the varying decay rates of each harmonic, and a method to estimate the strings plucking point, which is critical to the harmonic content of the sound.

Designing Curved Diffusers for Performance Spaces Trevor J. Cox Design optimization of performance space diffusers generates diffuser shapes that minimize energy distribution variations in the specular zone.These optimized diffusers generally outperform those based on the standard arc of a circle, although in some unbaffled cases the standard curved surface is the better difi'user choice within the optimization domain.

A Microphone Array for Multimedia Workstations Y. Mahieux, G. Le Tourneur, and A. Saliou 365 A controlled microphone array achieves a high directivity index using a cleverly designed transducer arrangement that shapes and controls the beamwidth. The system reduces noise and reverberation, which in a comparison test was preferred by listeners over a single unidirectional microphone tested in the same environment. ’ ' j.*. ,sj j An Analysis Procedure for Room Acoustics and Sound Amplification Systems Based on the Early-to-Late Sound Energy Ratio L. Gerald Marshall 373 Analysis of auditorium acoustics is performed using the early-to-late sound energy system.Constants for optimum speech or music are described and the energy-time curves by octave bands are analyzed for reflections in the 200-ms early time period. Software for this analysis system is available.

STANDARDS AND INFORMATION DOCUMENTS AES20-1996 AES recommended practice for professional audio — Subjective evaluation of loudspeakers .. 382 DRAFT AES28-xxxx, DRAFT AES standard for audio preservation and restoration — Method for estimating life expectancy of compact discs (CD-ROM) based on effects of temperature and relative humidity (insert) AES Standards Committee News 403 Listening-test standard; interconvention SC-10 meetings

FEATURES

Routing MIDI Messages Over ... Richard Foss and Thabo Mosala 406 1996 Directory of Educational Programs (insert)

DEPARTMENTS

Review of Acoustical Patents 404 In Memoriam 435 News of the Sections 416 Audio Engineering Society Application Sound Track 424 Instructions 437 Upcoming Meetings 426 AES Special Publications 440 New Products and Developments 427 Sections Contacts Directory 444 Available Literature 430 AES Conventions and Conferences 448 Membership Information 432

.u ! JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 44 NUMBER 6 1996 JUNE

CONTENT

PAPERS Binaural Technique: Do We Need Individual Recordings? ... Henrik Moller, Michael Friis Sorensen, Clemen Boje Jensen, and Dorte Hammershoi 451 In this study of individual binaural recordings, tiny microphones are fitted to the ear canals of the test individual Subsequent recordings are made using this setup for a like series of test subjects. The test subjects are then called upon to ascertain their ability to perceive the spatial and directional qualities of their individual recordings compared to other recordings made in the test group. The findings indicate fewer mean localization errors from individual binaural recordings. Nonindividual binaural recordings resulted in an increased number of distance errors.

Modeling the Nonlinearities in Horn Loudspeakers Wolfgang Klippel 470 Nonlinear parameters of horn loudspeakers are examined using a power series expansion while second- and third-order system functions are developed using the Volterra series\ The results are used to predict the harmonic and intermodulation products in the radiated sound pressure signal from, horn loudspeakers. These predicted criteria can be used to make systematic investigations into the audibility of nonlinear distortions in horn drivers by implementing block-oriented models in digital signal processors.

Computation and Memory Tradeoffs with Multiple Wavetable Interpolation Andrew Horner 481 A multiple wavetable interpolation technique is employed to match acoustic instrument tones via a genetic algorithm optimization in which the user defines the number of oscillators and wavetables to be used. Cross-fading between multiple wavetables interpolates the data, thus saving compilation time. Analysis of the findings indicates that using more than four oscillators results in diminishing returns.

Design of Logarithmically Spaced Constant-Directivity Transducer Arrays ..Menno van der Wal, Evert W. Start, and Diemer de Vries 497 The effectiveness of microphone and loudspeaker transducer arrays generally has been limited by beamwidths that vary with frequency. Here a new scheme is described for a broadband, controllable transducer array; which improves performance in many applications. Software control makes the system flexible for a variety of broad-based applications. CORRECTIONS Correction to “Constant-Beamwidth One-Octave Bandwidth End-Fire Line Array of Loudspeakers” 507 STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News. 508 Interconnections; style for preparation of standards

FEATURES AES 6th Australian Regional Convention Preview: Melbourne 514 Calendar .. 516 Exhibitors . 518 Exhibitor Previews 518 Updates and Corrections to the 1995/1996 AES International Sections Directory 521 DEPARTMENTS Review of Acoustical Patents 511 Membership Information 534 News of the Sections. .. 522 In Memoriam 542 Sound Track 530 AES Special Publications 544 Upcoming Meetings 532 Sections Contacts Directory 548 Available Literature 533 AES Conventions and Conferences 552 Yx::yv

rr- • • • a* .. JOURNAL OF THE ^ i: AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 44 NUMBER 7/8 1996 JULY/AUGUST CONTENT PAPERS Frequency and Angular Resolution for Measuring, Presenting, and Predicting Loudspeaker

Polar Data.... .•«!.!>tjk\ ...... Felicity Seidel and Henrik Staffeldt 555 The relationships between measurement resolution andthe accuracy of presented or predicted polar ^ '* * and frequency responses from single or arrayed loudspeakers are presented.Only direct loudspeaker- generated sound fields are addressed. Observations are made of current, commonly used measurement techniques, which can yield results with significant errors. The discussion includes the possible need to reconsider how loudspeakers should be measured, taking into account the increasing improvements in measuring equipment,data processing systems, and storage techniques. " 'v v ~r:. • :: -. ' • ' : =- 1; - . v = .=. ? H:. ,

A Model of Nonlinear Wave Propagation in Horns . .Keith R. Holland and Christopher L. Morfey , 569 .\ •: S' - . Sound propagation modeling in acoustic horns at high levels is analyzed. This model can predict the degree of nonlinear waveform distortion associated with propagation in the horn of large amplitude waves. The predicted output sound field can then be corrected for nonlinear distortion by appropriately predistorting the input signal, using the modeling-determined data. ’ A-Y - W ,/ ... -‘A ... Discrete Summation Synthesis of Musical Instrument Tones Using Genetic Algorithms k'- ....San-kuen Chan and Andrew Horner V 581 An automated genetic algorithm method determines discrete synthesis parameters for matching an arbitrary harmonic instrument tone. This work synthesizes the spectra of the trombone, English horn, and the Chinese pipa.This unique technique uses discrete summation matching ,which requires less computer memory compared to wavetable matching. Although the relative error using a wavetable is always smaller than that of discrete summation,it is a good alternative choice when wavetable memory is limited since it requires only a single sine wave.

ENGINEERING REPORTS

‘' Improving Audio Codecs by Notse Substitution Donald Schulz .‘ • 593 Separate coding of noise and signal components is proposed for greater data reduction. ^ Combinations of adaptive transform coding and adaptive subband coding using time and frequency domains in subbands distinguish between tonal and noisy audio components. Listening tests have confirmed the superiority of combined algorithms for a variety of different music signals, while the data rate was decreased by approximately 20%.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 599 AES3 interface meetings; loudspeakers and microphones

DRAFT AES-5id-xxxx, AES information document for Room acoustics and sound reinforcement system modeling — Loudspeaker modeling and measurement — Frequency and angular resolution for measuring, presenting and predicting loudspeaker polar data (insert)

FEATURES 100th Convention Report 610

Exhibitors .. ... ••••r ••• •• 624

Program ...... i ...... »i «*;*f* ...... *: 627 102nd Convention, Munich, Germany: Call for Papers 673

DEPARTMENTS Review of Acoustical Patents.. 603 Available Literature ..-,662 " News of the Sections ...... 654 Membership Information...... *;*. 664 Upcoming Meetings ...;. 656 In Memoriam 669 Sound Track 657 Sections Contacts Directory 676 New Products and Developments 658 AES Conventions and Conferences ...... 680 .A Y: • =!• : • • •»•=, - • •• A •!»... ' a i-.: J ;. 'tul -~5:. >*:£ , JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS / V - VOLUME 44 NUMBER 9 1996 SEPTEMBER CONTENT PAPERS Generalized Transaural Stereo and Applications Jerry Bauck and Duane H. Cooper 683 Precisely defined audio signals at the listeners ears using loudspeakers are discussed, including various applications of several other possible systems.The discussion covers several interaural delay compensation methods, which with other system features are designed to present the listener with a three-dimensional audio image. Historical approaches in the area of precise three-dimensional sound reproduction are also reviewed.

Lossless Coding for Audio Discs Peter Craven and Michael Gerzon 706 Lossless coding of data fully retains the original information. This method is free of the argument that can arise when using lossy compression schemes, which may discard some data as not important. Previously developed lossless data-compressing schemes are reviewed and their data- reducing advantages indicated. This paper will serve both the neophyte and digital practitioner well , with its concise analysis of audio data reduction methods.

Error Correction in Audio Amplifiers Dimitri Danyuk and George Pilko 721 The authors compare two generalized amplifier correction topologies and find that both exhibit the same sensitivities to changes in the main path as does negative feedback if analyzed on the basis of loop gain. Feedforward frequency compensation has no substantial advantages over conventional - frequency compensation methods in these findings. Regarding the phase margin that can be realized at a given closed-loop cutoff frequency, Miller compensation remains unmatched when compared to feedforward and pole-zero compensation. ENGINEERING REPORTS An Alternative Algorithm for Estimating and Tracking Talker Location by Microphone Arrays Ming Zhang and M. H. Er 729 Estimating and tracking talker locations when using microphone arrays are valuable tools in improving the overall quality of microphone utility in teleconferencing systems. Directed arrays can reduce reverberation and other extraneous unwanted sounds from the desired audio path by determining the direction of the talker s location and subsequently steering the microphone array toward the talker. A comparison is made to known radar methods, which points out that the problems in determining directionality and range of audio sources are more complex because of their wide frequency range.

STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News 737 . 101st Convention meetings DRAFT REVISED AESH-xxxx, AES Recommended practice for digital audio engineering — Synchronization of digital audio equipment in studio operations (insert)

FEATURES

101st Convention Preview: Los Angeles 742 Calendar 744

Exhibitors 746 ; • Exhibit Previews . 752 Updates and Corrections to the 1995/1996 AES International Sections Directory 790

DEPARTMENTS

Review of Acoustical Patents 738 In Memoriam ...... 796 " News of the Sections Report , 780 AES Annual .....*.v 799 Sound Track 785 AES Special Publications 800 - Upcoming Meetings 788 Sections Contacts Directory 804 Available Literature 788 AES Conventions and Conferences 808 Membership Information 791 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 44 NUMBER 10 1996 OCTOBER CONTENT PAPERS Nonlinear System Identification for Horn Loudspeakers Wolfgang Klippel 811 The dominant nonlinear mechanisms in horn loudspeakers when excited by small amplitude signals can be modeled using a class of polynomials known as SM systems. The amplitude and phase responses of linear subsystems are estimated in the SM system function by linear regression. The analysis gives qualitative clues to the dominant nonlinearities as well as quantitative estimates of relevant loudspeaker model parameters. This information is valuable for improving horn loudspeaker design and for developing correction filters with which to compensate for horn loudspeaker nonlinearities. Design and Commissioning of Sound Reinforcement Systems for the Australian Parliament— A Holistic Approach Glenn Leembruggen and David Connor 821 Speech reinforcement in the Australian Parliamentary Chambers presented unusually difficult conditions because of wide dynamic range, large orator-to-microphone distances, high levels of audience noise combined with architectural and acoustical constraints. The solution to providing high intelligibility with faithfid spectral reproduction included the use of original analytical software and unique tapered line-array loudspeakers. Commissioning the system involved numerical optimization of the gain structure and a novel acoustic loop-gain measurement technique to predict equalizations with which to optimize the acoustic gain margin.

Experimental Auralization of Car Audio Installations...... Emmanuel Granier, Mendel Kleiner, Bengt-lnge Dalenback, and Peter Svensson 835 Currently available architectural modeling software is not usable for studying automotive listening environments since these programs are optimized for large rooms. By employing other models the binaural room impulse response for low frequencies can be predicted in conjunction with an augmented geometrical acoustical model for high frequencies. Software for combining the separate low- and high- frequency modeling results is described and the findings are compared to preliminary listening tests. Analyzing Listening Tests with the Directional Two-Tailed Test ...Les Leventhal and Cam-Loi Huynh 850 Researchers typically analyze double-blind listening tests with a one-tailed significance test, which provides for deciding whether performance is better than chance. The little-known directional two- tailed test provides for deciding whether performance is better or worse than chance, and may be more useful to some investigators. These two tests are compared and further discussion is included on when and how to use them effectively. Extensive statistical tables are provided for conducting either test without the need for calculation. LETTERS TO THE EDITOR Addendum to “On the Acoustic Impedance of Baffled Strip Radiators” Stanley P. Lipshitz, Tony C. Scott, and Bruno Salvy 864 STANDARDS AND INFORMATION DOCUMENTS AES-2id-1996 AES information document for digital audio engineering — Guidelines for the use of the AES3 interface 865 AES Standards Committee News 893 Request for models; AES-24 protocol; digital audio measurements FEATURES Review of Society's Sustaining Members 898

DEPARTMENTS Upcoming Meetings 921 in Memoriam ... .. 935 News of the Sections 922 Audio Engineering Society Application Sound Track 926 Instructions 937 New Products and Developments 927 Sections Contacts Directory 940 Available Literature 929 AES Conventions and Conferences 944 Membership Information 931 -H JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 44 NUMBER 11 1996 NOVEMBER CONTENT

President's Message Elizabeth A. Cohen 947 PAPERS The Design of Encoding Functions for Stereophonic and Polyphonic Sound Systems Poletti 948 Encoding functions for ambisonic, stereophonic; and polyphonic sound reproduction systems can be designed for recordings made with elementary coincident microphones. Strong emphasis is placed on holographic reproduction systems that attempt to reproduce the original sound field in a region around the listener's head,

Compensation for Nonlinear Distortion of Horn Loudspeakers by Digital Signal Processing *: ^ ...... Klippel 964 Horn loudspeaker nonlinear distortion can be compensated by prefiltering the electrical input " i c inversely from the results of nonlinear loudspeaker modeling using static nonlinear and dynamic ' linear subsystems. This method requires less computational effort and memory than other genetic architectures. When using simplified versions of this filter, the performance of a professional horn >4 . loudspeaker was shown to be substantially improved by compensating only for nonlinear wave

: ' 1 ' ' : steepening. \ ' :!V ? : r „ ^ ' ' - * . Multichannel Signal Processing Techniques in the Reproduction of Sound P. A. Nelson, F. Orduna-Bustamante, and H. Hamada 973 A general approach to the design of inverse filters for multichannel sound reproduction systems is shown using algorithms that enable the rapid adaptation of inverse filters in response to the reproduced sound field. Experimental results and computer simulations illustrate the potential to manipulate stereophonic images to improve existing recordings. Experiments on a System for the Synthesis of Virtual Acoustic Sources P. A. Nelson, F. Orduna-Bustamante, D. Engler, and H. Hamada 990 Experiments are presented showing the subjective evaluation of a digital signal processing system designed to produce virtual acoustic sources at the listener's ears irrespective of the immediate sound reproduction environment. Several widely different environments are evaluated, with emphasis on the accuracy of localized images to the front, sides, and rear of the listener. STANDARDS AND INFORMATION DOCUMENTS AES18-1996 AES recommended practice for digital audio engineering — Format for the user data channel of the AES digital audio interface 1008

DRAFT AES3-1992 Amendment 1-xxxx, Amendment 1 to AES recommended practice for digital audio engineering — Serial transmission format for two-channel linearly represented digital audio data (insert)

..... AES Standards Committee News 1030 • ITU report on digital measurements; standards on CD-ROM /:>•

FEATURES 6th Australian Regional Convention 1034

Exhibitors...... *» « 1043 Program ... 1044 New AES Officers 1996/1997 1055

DEPARTMENTS Review of Acoustical Patents...... 1031 Available Literature ...... 1067 News of the Sections 1059 Membership Information..:... , 1068 Upcoming Meetings 1062 AES Special Publications 1071 Sound Track 1063 Sections Contacts Directory 1076 New Products and Developments 1065 AES Conventions and Conferences 1080

’• : :::.t , . . JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 44 NUMBER 12 1996 DECEMBER CONTENT Presidents’ Message Tim Shelton and Elizabeth A. Cohen 1083 PAPERS Co-talker Separation Using the “Cocktail Party Effect” Yuchang Cao, Sridha Sridharan, and Miles Moody 1084 The cocktail party effect is observed using two channels. These data are processed in an artificial neural network speech classifier. After a learning period during which the classifier becomes familiar with the desired speaker's voice characteristics, the classifier then controls the parameters of a modified Wiener filter to cancel out the interference. The simulation results have shown that the system consistently provides speech of good quality and intelligibility. An Integral Limitation upon Loudspeaker Frequency Response for a Given Enclosure Volume ...Jeffrey Harrison 1097 The tradeoff between volume, efficiency, and frequency response is stated in a key integral expression, which rules out the existence of a "magic" alignment for a superior performance. This had remained a possibility when using the traditional figure-of-merit approach. Multiple-cavity loudspeaker enclosures of the same volume show no efficiency advantage over single- cavity systems in this analysis. Compatibility Matrixing of Multichannel Bit-Rate-Reduced Audio Signals Warner R. Th. ten Kate 1104 Matrixing of bit-rate reduced audio signals may cause audible artifacts in both downmixing and demixing operations. The effect is more apparent in demixing since there is a strong correlation between the compatible and auxiliary signals. It is possible to preclude the occurrence of artifacts by using the same correlation between compatible and auxiliary signals. Sound Reinforcement by Wavefield Synthesis: Adaptation of the Synthesis Operator to the Loudspeaker Directivity Characteristics Diemer de Vries 1120 A linear array of loudspeakers that have arbitrary but identical directivity characteristics can be used to generate a reinforced soundfield with natural time and space properties by using wavefield synthesis based on Rayleigh's representation theorem. Individual loudspeakers in the array that have non-identical characteristics cannot, or can only partially, be corrected for by driving them with a signal that would be appropriate for an array of such loudspeakers. STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News 1132 Omission in draft revised AES11-xxxx; digital interface user format proposal; SC-02 Copenhagen meeting FEATURES 101st Convention Report 1134 Exhibitors 1150 Program 1154 AES News: Formation of Latin American Region 1178 1996/1997 AES International Sections Directory 1179 Call for Awards Nominations 1206 Call for Nominations for the Board of Governors 1207 AES 8th Tokyo Regional Convention, Call for Papers 1210 AES 103rd Convention, New York, Call for Papers 1212 Bylaws: Audio Engineering Society, Inc. 1214 Index to Volume 44 1218 DEPARTMENTS News of the Sections... 1198 Membership Information 1208 Sound Track 1202 In Memoriam 1209 New Products and Developments 1204 Sections Contacts Directory 1228 Available Literature 1205 AES Conventions and Conferences 1232 Upcoming Meetings 1205 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 45 NUMBER 1/2 1997 January/February

CONTENT

President’s Message: Quality of Service in an Open-Platform Infrastructure .....Elizabeth A. Cohen 3

PAPERS

Overview of MPEG Audio: Current and Future Standards for Low-Bit-Rate Audio Coding

...Karlheinz Brandenburg and Marina Bosi 4 ...... The development of the MPEG standards and their continued expansion for use in low-bit-rate audio coding are comprehensively reviewed. Details unique to several commercial encoding techniques that follow the guidelines of existing standards are presented. Extensive listening test data are included from the British Broadcasting System and NHK, Japan.

: • Perceptual Filters for Audio Signal Enhancement Dionysis E. Tsoukalas, John Mourjopoulos, and George Kokkinakis 22 A novel technique for removal of broadband noise relies on a psychoacoustic representation of the signals that uses a time-frequency varying perceptual filter to remove embedded broadband noise. The proposed perceptual filter can be a very powerful tool, capable of removing and psychoacoustically shaping perceptually significant noise while preserving the quality’ of the original music signal.

Digital Signal Processing Tools for Loudspeaker Evaluation and Discrete-Time Crossover Design Malcolm Omar Hawksford 37 A versatile technique for producing digital crossover alignments is presented together with its implications on cumulative design spectra (CDS ) and energy-time cur\ }es ( ETC ). A new method is proposed for masking polar response errors within the crossover transition band without affecting the on-axis target response.

STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News 63 102nd Convention meetings; internet communications; low-bit-rate data; S4 officers

FEATURES

102nd Convention Preview: Munich .... 66 Calendar .. 68 Exhibitors .... 70 Exhibit Previews 76 AES 103rd Convention, New York, Call for Papers (insert)

DEPARTMENTS

News of the Sections 93 Membership Information 104 Sound Track 98 In Memoriam 107 Upcoming Meetings . 100 Sections Contacts Directory 108 Available Literature .. 101 AES Conventions and Conferences 112

• * » :: : . ‘ T

: JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 45 NUMBER 3 1997 March CONTENT

President’s Message: Ubiquitous Audio Elizabeth A. Cohen 115

PAPERS The Detection Thresholds of Resonances at Low Frequencies Sean E. Olive, Peter L. Schuck, James G. Ryan, Sharon L. Sally, and Marc E. Bonneville 116 Listeners' detection thresholds of low-frequency resonances and antiresonances were measured for a single resonance ( peak and notch ) for different Qs and center frequencies using several signal types. These tests were designed, to help understand the relationship between loudspeaker and listening room interactions. The experimental results show that detection thresholds are complex and are *•:! affected by Q, center frequency, and signal type. - Precision Measurement of Loudspeaker Parameters David Clark 129 Reliable measurements of loudspeaker position-dependent parameters are achieved by using pneumatic pressure to displace the cone of the loudspeaker under test. This method reduces the variations between successive measurements, thereby improving the reliability and utility of the • . _ measurements. ... Position-Independent Enhancement of Reverberant Speech ...... D. Cole, M. Moody, and S. Sridharan 142 Conventional enhancement of single-channel reverberant speech is a somewhat cumbersome two- step process. The authors' proposed new method is based on the obser\>ed segmental spectral magnitude characteristics of room impulse responses. This novel system greatly reduces the positional sensitivity of speaker-to-microphone placement while improving the speech perception in a reverberant environment. ' • “ "'"V'V-. /.7 Modeling Small Chinese and Tibetan Bells Andrew Horner, Lydia Ayers, and Daniel Law 148 The spectral properties of small Chinese and Tibetan bells were examined for their amplitude modulations and occasional synchronous frequency modulations. These characteristics were modeled and synthesized. Listening tests have found the resultant synthesized sound to be indistinguishable 'v " ' - • •• * - from the original bell sound. * • , , p

LETTERS TO THE EDITOR Comments on “An Introduction to Band-Pass Loudspeaker Systems” Yong Shen, Bo-ling Xu, and Jia-zheng Sha 160 Author's Reply ..Earl Geddes 160

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News 162 Status of projects

FEATURES Technological Change: The Challenge to the Audio and Music Industries John Strawn 170 Updates and Corrections to the 1996/1997 AES International Sections Directory 185 Updates to Review of Society's Sustaining Members T95

DEPARTMENTS Reviews of Acoustical Patents 165 Membership Information .198 News of the Sections 188 Audio Engineering Society Application Upcoming Meetings 190 Instructions ... ..201 Sound Track 191 Sections Contacts Directory 204 New Products and Services .... 193 AES Conventions and Conferences 208 Available Literature 196 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 45 NUMBER 4 1997 April

CONTENT

President’s Message Conferences, Copyright: Seeing and Hearing Elizabeth A. Cohen 211

' : = : v/V (’N " 1- • PAPERS ^ . :?4*"V Psychoacoustically Optimal Sigma-Delta Modulation Chris Dunn and Mark Sandler 212 Noise characteristics of high-resolution sigma-delta modulation audio converters have been investigated by the authors and they have identified two desirable attributes: 1 ) the noise floor should be free of idle tones, and 2 ) other low-level artifacts in the noise floor should be minimally audible. Dither can be used to linearize sigma-delta modulators, while careful choice of noise-shaping zero - VH'ir locations can affect psychoacoustically appropriate shaping of the modulator noise floor. fV

A Model for the Prediction of Thresholds, Loudness, and Partial Loudness Brian C. J. Moore, Brian R. Glasberg, and Thomas Baer 224 A loudness model utilizing two filters is presented that emulates the outer and middle ear. This system !"- n?

to It ' transforms the excitation pattern a specific loudness pattern. accounts for the threshold and S'.- ' loudness of complex sounds as a function of bandwidth This model correctly predicts the relationship between monaural and binaural thresholds and loudness.

Wavetable Modeling of Muted Brass Tones Andrew Horner 241 Wavetable matching is used to model open tones for brass instruments with an additional wavetable that matches the muted tones. This method is more accurate than those employing simple filter characteristics, since it can also simulate partially muted and dynamic muted tones. Spectrograms that illustrate the results are included for various mutes on the trumpet, trombone, and French horn.

Sound Absorption of Gypsum Board Cavity Wails J. S. Bradley 253 A calculation model was developed to predict the sound absorption of several cavity-type gypsum- board walls that accurately fits the measured data. This model can be used, to predict both low- and high- frequency losses effectively in hollow gypsum-board wallconstruction. It is a valuable tool in designing walls with a specified minimal amount of low-frequency absorption.

STANDARDS AND INFORMATION DOCUMENTS

AES11-1997 AES recommended practice for digital audio engineering Synchronization of digital audio equipment in studio operations 260

AES Standards Committee News 270 Scopes of subcommittees and working groups; symbols standard rV: r • - *

FEATURES : ?..-uyu

AES 14th International Conference, Seattle, Washington: “internetaudio.aes.org”. 276 Calendar 277 Program .i...... 278 , Updates and Corrections to the 1996/1997 AES International Sections Directory ... 287 ,„v . :, Special Supplement to 1996 Directory of Educational Programs (insert)

DEPARTMENTS Reviews of Acoustical Patents .....273 Available Literature 300 News of the Sections ...... 289 Membership information...... 302 Upcoming Meetings 294 In Memoriam ...... r.l...... 307 , Sound Track 295 Sections Contacts Directory 308 New Products and Services .... 297 AES Conventions and Conferences 312

> -i.

-.S-i \W - U5- “'!• JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 45 NUMBERS 1997 May

CONTENT

President’s Message The AES: The Voice of Technical Leadership Elizabeth A. Cohen 315

PAPERS Hybrid Sampling-Wavetable Synthesis with Genetic Algorithms Jennifer Yuen and Andrew Horner 316 A combination of hybrid sampling and wavetable synthesis for matching acoustic instruments is demonstrated using genetic algorithm optimization. Tone sampling is used for the critical attack portion and wavetable synthesis is used to match the more gradually changing sustain and decay. A hybrid sampling wavetable performs a smooth crossfade transition. This method has been used to synthesize piano, harp, glockenspiel, and temple block tones. Measurement of Directional Scattering Coefficients Using Near-Field Acoustic Holography and Spatial Transformation of Sound Fields...... Mendel Kleiner, Hans Gustafsson, and Joakim Backman 331 Near-field holography is used to measure the sound field above the surface of an acoustical scatterer. The scattered sound field is then spatially transformed to the desired distance and angle; the angle corresponds to a specific angle relative to the surface normal This method can predict the sound field at close distances to the scattering object, while the data storage requirement is smaller than conventional polar response measurements.

Fundamentals of Diffraction ,J. R. Wright 347 Basic theoretical and practical analysis has been performed to clarify the physical attributes of diffraction. Using finite element analysis ( FEA) simple measurements corroborate the evidence of this study. Several methods are used to illustrate the diffraction effect. The author suggests that further detailed physical understanding of the diffraction mechanism is still desired.

ENGINEERING REPORTS Optimizing the Voice-Coil-Airgap Geometry for Maximum Loudspeaker Motor Strength Carlo Zuccatti 357 The strength of a loudspeaker motor can be optimized by designing a voice coil that overhangs slightly the magnetic field gap. The stray field at the gap's edge can be engaged additionally to increase the overall strength of the motor force.

STANDARDS AND INFORMATION DOCUMENTS AES28-1997 AES standard for audio preservation and restoration — Method for estimating life expectancy of compact discs (CD-ROM), based on effects of temperature and relative humidity 360

AES Standards Committee News...... 379 Internet subcommittee formation; SC-02, SC-04, and SC-05 meeting reports

FEATURES 102nd Convention Report... 386 Exhibitors 398 Program 402 8th Regional Convention, Tokyo, Japan: Preview (insert)

DEPARTMENTS

News of the Sections ...... 422 Available Literature 431 Sound Track ...... 426 Membership Information...... 432 New Products and Services 429 Sections Contacts Directory 436 , Upcoming Meetings ...... 430 AES Conventions and Conferences >* « 440

-A: k JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 45 NUMBER 6 1997 June CONTENT

President’s Message: The Evolution of Standards Elizabeth A. Cohen 443 PAPERS Digital Parametric Equalizer Design with Prescribed Nyquist-Frequency Gain ...... Sophocles J. Orfanidis 444 A new class of second-order digital parametric equalizers is shown that closely matches its analog counterpart over the entire Nyquist interval This digital configuration does not suffer from the prewarping effect of the bilinear transformation. An additional degree of freedom is introduced in this design, namely, gain at the Nyquist frequency. Virtual Sound Source Positioning Using Vector Base Amplitude Panning Ville Pulkki 456 A vector-based reformulation of amplitude panning is shown that uses simple and computationally efficient equations for accurate, virtual sound-source positioning. This method, vector base amplitude panning (VBAP ), makes possible the creation of two-dimensional and three-dimensional sound fields using multiple loudspeakers that are set in an arbitrary placement. It is claimed that VBAP produces virtual sound sources that are as sharp as those possible with current loudspeaker configurations that use amplitude panning. ENGINEERING REPORTS Digital-Domain Dithering of Sigma-Delta Modulators Using Bit Flipping ...... Anthony J. Magrath and Mark B. Sandler 467 A new technique is introduced for dithering sigma-delta modulators directly in the digital domain, eliminating the need for an analog dither source or the use of chaos. This reduces the analog circuit complexity. The system design reduces noise modulation at low input levels and extends the dynamic range by reverting back to an undithered modulator at high input levels. Digital Power Amplification Using Sigma-Delta Modulation and Bit Flipping Anthony J. Magrath and Mark B. Sandler 476 A novel data conversion scheme suitable for power digital-to-analog conversion is based on a modified sigma-delta modulator. It is proposed that the digital-to-analog converter translate a 44.1/48-kHz format pulse-code-modulated ( PCM ) digital audio signal to an oversampled single-bit signal. This signal then controls a high-power MOSFET switch. Its output signal is passively filtered to reconstitute the analog signal, which can then be applied directly to the loudspeaker. LETTERS TO THE EDITOR Comments on “Spice Models for Vacuum-Tube Amplifiers” Eric K. Pritchard 488 Author's Reply W. Marshall Leach, Jr. 489 Comments on “Spice Models for Vacuum-Tube Amplifiers” Frederic Broyde. Evelyne Clavelier, and Charles Hymowitz 490 ...... Charles Rydel 491 Author's Reply.... W. Marshall Leach, Jr. 493 CORRECTIONS Corrections to “Digital Signal Processing Tools for Loudspeaker Evaluation and Discrete-Time Crossover Design” Malcolm Omar Hawksford 497 STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 498 Computer audio; flutter; multiple-contact connector database FEATURES The AES Technical Council and Its Committees Tim Shelton 502 DEPARTMENTS News of the Sections.... 508 Membership Information...... 522 Sound Track .516 In Memoriam ...... 531 Upcoming Meetings 517 Sections Contacts Directory...... 532 New Products and Services.... 518 AES Conventions and Conferences 536 Available Literature 521 :x EE?i • • : a ; E =3 :~E: . - > = -* ... . . • :< > ::E ,::.i. .V; .i ;V ¥ . . % . T < ^ ^ JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 45 NUMBER 7/8 1997 July/August :6;- • V .1- '. ! CONTENT

President’s Message: Future Technical Leadership Audible at AES Meetings Elizabeth A. Cohen 539

PAPERS Fractal Wavelet Compression of Audio Signals : is . Robert A. Wannamaker and Edward R. Vrscay 540 Wavelet transform coding and fractal-based compression are combined in an audio signal compression technique. The signal is divided into frames that are subjected to a fast wavelet transform, with subsequent fractal coding of high-frequency coefficients using a collage approach. Modest compression ratios have been achieved, according to the authors. However, ratio increases above 6:1 should be attainable with further work. High-Fidelity PWM-Based Amplifier Concept for Active Loudspeaker Systems with Very Low Energy Consumption Karsten Nielsen 554 A pulse-width-modulation amplifier is described for use withwoofer and midrange loudspeaker loads operating at frequencies below 4 kHz. design is bqsef opq new feedback topology and a The .. . . bandwidth-dependent-modulation strategy\and employs a relatively low switching rate of 44.1 kHz. The power output stages exhibit excellent efficiency rates that approach 96% at high output levels. Processing of Musical Tones Using a Combined Quadratic Polynomial-Phase Sinusoid and Residual (QUASAR) Signal Model Yinong Ding and Xiaoshu Qian 571 The authors have developed a data reduction system for music analysis and synthesis that uses 33% less memory than previous systems while reducing the computational requirements by 50%. This > V< =/.:> •

: novel system a model that combines polynomial phase sinusoids and : 5 proposes signal quadratic - a -: residual for music analysis and synthesis. The algorithm is being adapted currently to a commercially available fixed-point digital signal processor. Precise Passive Crossover Networks Incorporating Loudspeaker Driver Parameters

» « v «v « V «» ». » > ; / * •**• • *• * ** *> ..•- •.* *.v** . *.A N. Thiele 585 The author describes loudspeaker crossover design procedures that use networks to interact with the , loudspeaker's electrical parameters and equalize its response into that of a second-order high-pass filter. A further network corrects the driver impedance. The equalized driver is then cascaded with a passive equalizer and a conventional ladder filter to achieve the required higher order response.

‘ . ...i. '• { •= . - . S LETTERS TO THE EDITOR AES Policy on World Wide Web Publication .... ;; .....Steven Harris 595 i :iy* Editor's Reply Daniel R. von Recklinghausen 595

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...::: .... 596 103rd Convention meetings; peformance loudness; mechanical media; Internet audio meeting i'*

FEATURES AES 103rd Convention Preview: New York 602 Calendar 604 Exhibitors ....:: 606

' ::: ' Exhibit Previews .1

' DEPARTMENTS • ii?' -i Review of Acoustical Patents... u m . 599 Available Literature ... 644 News of the Sections 637 Membership Information 646 Sound Track ...... 642 Sections Contacts Directory 652 Upcoming Meetings 644 AES Conventions and Conferences .656 :! •=!!’= ? ¥ : ' • Ht • a. i •I • •• ? & ;» .. -: - : ^ : : S IS : :. y K :y.\ ' fa- < . ;- ‘ 5=;.. '”54>:i \vU %

; Jv ^

« • • vv\. . ' . - - v s v

JOURNAL OF THE •

AUDIO ENGINEERING SOCIETY s

•‘ N ' k; • » : • AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 45 NUMBER 9 1997 September i.,- "A: • • • . .Uv h. rc.

CONTENT ’.i .. ' • V

y -i- 1 President’s Message: Need for Awareness in Audio :-i- - ...... Elizabeth A. Cohen 6597 V -v ;:•* <; ;U PAPERS Effect Design: Part 1 Reverberator and Other Filters Jon Dattorro 660 The author has written a comprehensive three-part toolbox paper, which is intended to serve as a ; tutorial point of reference for digital audio effects that are frequently used by the electronic music industry. In this first part, reverberation, musical filtering , and Chamberlin filter topology algorithms ' ‘ 1 iW are discussed. Included in each of these subjects are historical background, pertinent references, ,Ti and appendices to further aid the reader's understanding of the subject materials.

Personal Sound.., W. F. Druyvesteyn and J. Garas 685 - : Methods of isolating multiple sound sources within a single room that permit different persons to % k listen to individual and personal sound sources have been investigated. Although no isolation criteria between listeners are proposed in this paper, useful data are developed by several possible sound source isolation methods in reverberant and nonreverberant environments. Design of a Loudspeaker System with a Low-Frequency Cardioidlike Radiation Pattern

* * * >.V « « a «•;* « a ..Marinus M. Boone and Okke Ouweltjes 702

A loudspeaker system based on a combination of monopole and dipole radiators,which is driven by : =!- : ! specially preprocessed audio signals, can generate a cardioidlike unidirectional low-frequency V radiation pattern. In public address systems this method reduces acoustical feedback and can reduce the number of secondary low-frequency acoustical paths within an enclosed environment.

ENGINEERING REPORTS H Meng 708 Listener Differences in Audio Compression Evaluations Kristin Precoda and Teresa . ^ This study investigates variations in perceptual grading of audio compression schemes in terms of data deviations between diversified groups and different locations. Divergent listener strategies and the variable auditory perceptions of the “average” listener have significant implications for how data may be combined sensibly and applied across a diversified listener base. ^ ; i f

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News 716 Patent policy; IEEE 1394; 96 kHz

DRAFT AES3-1992 Amendment 2-xxxx DRAFT Amendment 2 to AES Recommended practice for iiV digital audio engineering — Serial transmission format for two-channel linearly represented v7 digital audio data (insert)

FEATURES

AES 14th International Conference Report: Seattle, Washington, USA 722 AES 104th Convention, Amsterdam, The Netherlands: Call for Papers 753

DEPARTMENTS . ' ! . •' 1 ” I: . x. • * = - . * v; : ' v 4 : •'. \ .74 w , :y s X : ' & % rv: , ' i JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 45 NUMBER 10 1997 October CONTENT President’s Message Subir K. Pramanik 763

PAPERS Effect Design: Part 2 Delay-Line Modulation and Chorus Jon Dattorro 764 The author has written a comprehensive three-part toolbox paper, which is intended to serve as a tutorial point of reference for digital audio effects that are frequently used by the electronic music industry. In this second presentation,linear interpolation, all-pass interpolation, and white chorus effects including flanger algortihms are discussed. Historical background, pertinent references, and appendices are included on each of these subjects to further aid the readers understanding.

ISO/IEC MPEG-2 Advanced Audio Coding Marina Bosi, Karlheinz Brandenburg, Schuyler Quackenbush, Louis Fielder, Kenzo Akagiri, Henrik Fuchs, Martin Dietz, Juergen Herre, Grant Davidson, and Yoshiaki Oikawa 789 The main features of the MPEG-2 advanced audio coding ( AAC ) system ( ISOIIEC 13818-7 ) are described in this paper. The AAC system was designed to provide MPEG-2 with the best audio quality without compatibility-based restrictions. MPEG-2 AAC combines the coding efficiency of a high- resolution filter bank, prediction techniques, and Huffman coding with additional functionalities ^ aimed at delivering very high audio quality at a variety of data rates. According to the current plans of ISO/IEC MPEG, the AAC system will be the last very high quality audio standard for the foreseeable future.

Learning Algorithms for Audio Signal Enhancement: Part 1 Neural Network Implementation for the Removal of Impulse Distortions Andrzej Czyzewski 815 Unique learning algorithms were used to analyze impulse distorted audio signal fragments. The purpose of these algorithms was to aid in eliminating impulse distortions in old records and transmitted audio signals. The results of these studies indicate that neural networks are an appropriate tool for detection and removal of impulsive disturbances when using nonlinear predictive interpolation of missing signal intervals.

TDFD-Based Measurement of Analog-to-Digital Converter Nonlinearity ...James Rathmeli, Jonathan Scott, and Anthony Parker 832 Analog-to-digital converter nonlinearity is measured using the standard audio total difference frequency distortion (TDFD ) method. In this system two signal frequencies are applied to the device under test and the resulting intermodulation products are then identified. The TDFD measurement method has the advantage of being relatively insensitive to the harmonic content of the input test signals; it is easier to produce a valid intermodulation test signal than it is to produce a test signal of low harmonic content to measure harmonic distortion.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 841 DVD audio; Internet audio

DRAFT REVISED AES24-1-xxxx DRAFT REVISED AES standard for sound system control — Application protocol for controlling and monitoring audio devices via digital data networks — Part 1: Principles, formats, and basic procedures (insert)

FEATURES New AES Officers 1997/1998 ...v 844 Review of Society’s Sustaining Members 851 Updates and Corrections to the 1996/1997 AES International Sections Directory 883

DEPARTMENTS News of the Sections 873 Available Literature 881 Sound Track 877 Membership Information 885 New Products and Developments 879 Sections Contacts Directory ...... 892 Upcoming Meetings 881 AES Conventions and Conferences 896 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 45 NUMBER 11 1997 November CONTENT PAPERS Learning Algorithms for Audio Signal Enhancement:Part 2 Implementation of the Rough-Set Method for the Removal of Hiss ...... Andrzej Czyzewski 931 Learning algorithms were used to analyze strong hiss and impulse noise from old phonograph records.The method was tested with consideration to the ongoing automatic threshold setting requirement in spectral filtering of noisy audio.The threshold algorithm applied to this task must be adaptable, since the spectrum of the signal is time-variant and changes its character with each passing moment of time.Consequently, there was a need to employ an intelligent algorithm with strong generalization capabilities for building a knowledge base of signal and hiss relations.These data were then used for the automatic threshold updates while processing the entire noisy audio spectrum. ‘v* ENGINEERING REPORTS Visual Monitoring of Multichannel Stereophonic Signals Setsu Komiyama 944 A new type of visual monitor for multichannel audio signals is presented that serves as a visual tool for the production staff.This novel monitor displays directional balance and phase relationships among the multichannel signals by visualizing an instantaneous sound intensity vector that is will replace synthesized by the multichannel signals.It is intended that this new monitor the Tv-Vf conventional Lissajous stereo pattern monitor. Discrete-Eiement Line Arrays—Their Modeling and Optimization David L. Smith 949 The author conducted near-field andfar-field polar measurements on discrete element loudspeaker line arrays to determine their most effective design for domestic use. In a home setting it was shown that the near-field performance dominated for long arrays and that improvementstothe array s forward beam would most benefit the listener at near range. Level tapering schemes applied to the arrays were also found to be useful in giving improved response smoothness for any listening height at typical home listening distances. STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 965 Digital interface synchronization and sampling DRAFT REVISED AES17-xxxx DRAFT AES standard method for digital audio engineering — Measurement of digital audio equipment (insert) FEATURES 8th Tokyo Regional Convention Report .. 970 Exhibitors 977 < Program 978 103rd Convention Report, New York 984 Exhibitors .. 998 Program 1002 Call for Awards Nominations 1036 DEPARTMENTS Review of Acoustical Patents 968 Membership Information 1038 News of the Sections 1029 Audio Engineering Society Application Sound Track 1032 Instructions 1041 Upcoming Meetings 1034 Sections Contacts Directory ...... 1044 < New Products and Developments 1035 AES Conventions and Conferences ..... 1048 Available Literature 1037

; ' i :•

' •V-K

'V ..

• - JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 45 NUMBER 12 1997 December CONTENT PAPERS Acoustics of the Former Teatro “La Fenice” in Venice Lamberto Tronchin and Angelo Farina 1051 Objective measurements were made of this unique concert hall to determine its acoustical characteristics relative to its subjective listening reputation.Various types of acoustical measurements were made with results that indicate the hall is well suited for opera and speech, whereas the reverberation time appeared too short for symphonic music.The measurement results support the earlier subjective evaluations of the hall.

Improvement of Signal-to-Noise Ratio in Long-Term MLS Measurements with High-Level Nonstationary Disturbances Johan L. Nielsen 1063 A simple scheme for automatic improvement of signal to M*-“*< * * the - -noise ratio in long-term maximum- lV

ENGINEERING REPORTS Development of a Low-Flutter Measurement Tape Lowell Cross 1067 A high-speed recording technique is used to make magnetic tapes for use in making flutter measurements. The recorder uses a high-speed servo-system-controlled transport mechanism to record flutter measurement tapes, which are subsequently played back at standard speeds.The high- speed recording technique produces a significant reduction in the recorded flutter and improves the accuracy of flutter measurements, especially when compared to the common procedure of recording flutter tapes at playback velocities.

Improved Spice Model for Triode Vacuum Tubes Walter Sjursen 1082 An improved PSpice analog behavioral model for triode vacuum tubes is shown as nonlinear functions of grid and plate voltages.This model includes the effects of initial electron velocity, low plate voltage, and positive grid voltage. These improvements provide more accurate simulation of the triode circuits, which operate at low plate currents, low plate voltages, or with positive grid voltages.

STANDARDS AND INFORMATION DOCUMENTS AES22-1997 AES recommended practice for audio preservation and restoration — Storage and handling — Storage of polyester-base magnetic tape 1089 AES Standards Committee News... 1110 DVD-audio

FEATURES Automated Digital Audio Archives in the Broadcasting Environment Giorgio Dimino 1124 1997/1998 AES International Sections Directory 1134 Call for Nominations for the Board of Governors 1167 AES 105th Convention, San Francisco, Call for Papers 1170 Bylaws: Audio Engineering Society, Inc 1172 Index to Volume 45 1176

DEPARTMENTS News of the Sections 1156 Available Literature 1166 Upcoming Meetings 1161 Membership Information 1168 Sound Track 1162 In Memoriam 1169 New Products and Developments 1164 AES Conventions and Conferences 1184 zzsmr r rriov;s £a;v;:. :n.i 7.i”. i.; rt s : : '";x: -:c:r 'r:r,;rrr1S::;'J-.Y. SV:.Y «;::I::? : ^..- -. . -^. ^ -- ^ ^ * ~ . . .. . ' J ' •Vff #F g % 1. % JOURNAL OF THE

“* ..t:ri! XJ rr .v “.'Y:~;T.:.T.:r;. ;xx: :.. .v - ,. > s .-1:vX:cr». ;YI;rai:,Y S£U.£;;ii;yu vv Y-' .n ~:r::: -iss:;; ' ^ - - ^ - * ^ ^ ^ ^' i %x 3 • if m si2% AUDIO ENGINEERING SOCIETY

, / ' , • • ' ; j T v ^ i j ; 3gc ;cj g : fy ' gK g gK : ' ' " ' -^Tcy ~ i ~ ~ ~ ~ ; i- ; - - ;; • ; ; ‘ ; v ; ' ' V7 a aaa rtr irr - l; :.7 .x ’... ..:« w .uaD . ru.tiz > v.x -^ rr i ua&7.- .ft:4 a .: 5na ?: - ~ i«.!iiT?‘.7“ » >l . = .. ...vn: : > rr. . r. v :..:. ^ r . .r KSMil - * ^ ~ ^ ^ ^^ ^ ^ - ^ * * - - - - ^ ^ - - - fK ES t5\ Pi m if > VI4 -;• *• / / nw . - v AUDIO ACOUSTICS APPLICATIONS ' r ;,_ - ;r: V .7 i ' ' Jj: x crarr.' ; m vlt V;^ .f.I-'iW M ' J.a .wx . .--.".-.— '.3i «eJZJ ^:JLTK *:wxivxmzi » ^ ' — = VOLUME 46 NUMBER 1/2 1998 JANUARY/FEBRUARY

CONTENT

Foreword ...John J. Bubbers 3 President’s Message Subir K. Pramanik 4

I. HISTORICAL DOCUMENTS

Reminiscences on the Founding and Development of the Society Donald J. Plunkett 5 Charter Members 6 Officers/Governors/Editors 1949-1998 7 Conventions and Conferences 1949-1997 13 Audio Engineering Society Awards Recipients 17

II. TECHNOLOGICAL REVIEW

Highlights in the History of Multichannel Sound Emil Torick 27 Magnetic Recording ...John J. Bubbers 32 Dawn of the Digital Age Stanley P. Lipshitz 37 Fifty Years of Loudspeaker Developments as Viewed Through the Perspective of the Audio Engineering Society Mark R. Gander 43 Electronic Technology W. Marshall Leach, Jr. 59 Acoustics in the Audio Engineering Society Manfred Schroeder 71

III. SOCIETY COMMITTEE ACTIVITY

Standards in the AES... John Nunn 74 Education and the AES ..Roy Pritts 88

IV. INTERNATIONALIZATION, GROWTH, AND FUTURE OF THE SOCIETY

Introduction ....John J. Bubbers 94 AES British Section John Borwick 94 AES Goes Europe Peter K. Burkowitz 98 Personal Memories of the AES in Eastern Germany and Eastern Europe ....Gerhard Steinke 103 Brief History of the AES Japan Section Akihiko Takasu and Katsuya (Vic) Goh 108 The Growth of the AES in Australia A. N. Thiele, Fabian Horton, David Hudson, David Murphy, and John D. Smyth 111 The AES and Its Future Roger K. Furness 115

V. THE AUTHORS 117

VI. SOCIETY COMMUNICATIONS

AES Special Publications 123 Audio Engineering Society Membership Application Instructions 128 Sections Contacts Directory 131 AES Conventions and Conferences 136 JOURNAL OF THE A AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 46 NUMBER 3 1998 MARCH CONTENT PAPERS Thermal Time Constants and Dynamic Compressibility of Air in Fiber-Filled Loudspeaker Enclosures Gavin R. Putland 139 The frequency response of a fiber-filled loudspeaker enclosure is influenced by the heat conduction between the fibers and the enclosed air: The heat conduction rate involves a time constant whose value is dependent upon which conditions are held constant during the heat transfer period. In this study, five constants are derived and their results compared to previous studies. A Comparison of Computational Methods for Instantaneous Frequency and Group Delay of Discrete-Time Signals V. C. Georgopoulos and D. Preis 152 A unified treatment of various computational methods for estimating the instantaneous frequency and group delay of discrete-time signals is given. Direct, phase-based methods are compared to the newer moment methods. Instantaneous frequency and group delay are mathematical duals of each other; so that an algorithm suitable for estimating one can be used, with a simple interchange of time and frequency variables, to estimate the other. A wide variety of test signals are used to compare the performance of these methods, and their advantages and disadvantages compared. ENGINEERING REPORTS Subjective Evaluation of State-of-the-Art Two-Channel Audio Codecs ...... Gilbert A. Soulodre, Theodore Grusec, Michel Lavoie, and Louis Thibault 164 Several two-channel audio codecs were compared to a CD-quality reference in subjective double- blind tests. These studies were designed to determine the comparative audio quality of various codecs.The tests considered only audio quality with respect to bit rate for a series of codecs. Methods for Reducing Audible Artifacts in a Wavelet-Based Broad-Band Denoising System ...Pavan K. Ramarapuand Robert C. Maher 178 A denoising algorithm, which is based on the assumption that broad-band noise cannot be efficiently represented by any of the bases in a library of wavelets, has removed broad-band noise from recorded music signals. The goal of the system was to enhance the music without removing a perceptible amount of musical content. The results indicate that the broad-band noise was largely eliminated, although some minor artifacts, such as faint birdlike noise and warble did arise.These irregularities remain for future investigation. STANDARDS AND INFORMATION DOCUMENTS AES-5id-1997 AES information document for room acoustics and sound reinforcement systems — Loudspeaker modeling and measurement — Frequency and angular resolution for measuring, presenting, and predicting loudspeaker polar data 191 DRAFT AES3-1992 Amendment-3-xxxx DRAFT Amendment 3 to AES Recommended practice for digital audio engineering — Serial transmission format for two-channel linearly represented digital audio data (insert) AES Standards Committee News 217 104th Comention meetings; representation of audio levels in articles and specifications

FEATURES AES 104th Convention Preview, Amsterdam 226 Calendar . 228 Exhibitors .... 230 Exhibit Previews ..... 236 Student Delegate Assembly Established 254 Updates and Corrections to the 1997/1998 AES international Sections Directory .... 257 Updates to Review of Society’s Sustaining Membership 261 DEPARTMENTS Review of Acoustical Patents 222 Available Literature ...... 258 News of the Sections 248 Membership Information 263 Sound Track 255 Sections Contacts Directory ...... 267 Upcoming Meetings 256 AES Conventions and Conferences 272 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 46 NUMBER 4 1998 APRIL CONTENT Introduction David Meares - 275 PAPERS The Use of in the Context of Surround Sound Program Reproduction .Nick Zacharov, Soren Bech, and David Meares 276 Placement of subwoofers for enhancement of television multichannel sound in a domestic environment is noncritical for the reproduction of 5.1-channel audiovisual material below 85 Hz. C : Subjective Appraisal of Loudspeaker Directivity for Multichannel Reproduction Nick Zacharov 288 High-directivity loudspeakers in multichannel reproduction provide less excitation to the reproduction room boundaries. This results in fewer room reflections, so that essential directional cues are reproduced more faithfully. . T Calibration of Relative Level Differences of a Domestic Multichannel Sound Reproduction System Soren Bech 304 The type of calibration signals to set relative loudspeaker levels in a multichannel reproduction system must be evaluated with regard to immediate environmental factors.The listening room, program material, and reproduction system must be considered to establish a meaningful calibration level for domestic multichannel sound reproduction systems. ; ; The Influence of Stereophonic Width on the Perceived Quality of an Audiovisual Presentation Using a Multichannel Sound System Soren Bech 314 The spatial quality of reproduced sound for both audiovisual and audio-only program material increases with increasing stereophonic width and reproduction sound level. Independent of playback level and stereophonic width, spatial quality decreases as the listening position moves off center. jp J Program Origination of Five-Channel Surround Sound..D.G. Kirby, N. A.F. Cutmore, and J. A. Fletcher 323 Multichannel sound offers much improved performance over that of two-channel sound. Additional microphones for the surround channels contribute a worthwhile spatial quality improvement to the surround sound presentation. Matrixed Surround Sound in an MPEG Digital World D. J. Meares and G. Theile 331 The introduction of digital multichannel compressed sound service need not result in the loss of Dolby Stereo services. Inclusion of these options require using Dolby Stereo-capable MPEG encoders, , which need a slightly higher bit rate than two-channel stereo for the same overall audio quality. Dynamic Range Control (DRC) for Multichannel Audio Systems Wolfgang Hoeg 336 A compatible dynamic range control system is proposed for multichannel transmission or storage in accordance with ITU-R and ISO!MPEG-2 standards to accommodate the domestic listener.Implemen- tation is achieved by inserting a control signal into the transmitted multichannel audio bit stream.' Dynamic Range Control in a Multichannel Environment A. F. Cutmore 341 Generating a dynamic range control signal appears to be more complex for multichannel signals than for stereophonic programs. In this proposal there are more than one dynamic range control signals available to accommodate a variety of future multichannel audio program encoding needs. STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 1...... 348 AES-24 comments; tape flutter; digital audio measurements; sound-system modeling; Internet audio; connectors DRAFT REVISED AES5-xxxx Draft revised AES Recommended Practice for Professional Digital Audio Applications Employing Pulse-Code Modulation — Preferred Sampling Frequencies (insert) FEATURES Microphone and Mixing Techniques for Multichannel Surround Sound Francis Rumsey 354 DEPARTMENTS , Reviews of Acoustical Patents..... 352 Membership Information...... » - rV~372 r News of the Sections .....360 Audio Engineering Society Application Sound Track 366 ; .. . Instructions v:* ? ...... 376 Upcoming Meetings ...... 367 Sections Contacts Directory— 379 r New Products and Developments 368 AES Conventions and Conferences 384 Available Literature ...... 370

• y S' ,- y : " r : ;.V; iW: • ...yv 0 > it ’ ’ 0- 0 ' : '. i! JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 46 NUMBERS 1998 MAY

CONTENT PAPERS The “Stereo Dipole”—A Virtual Source Imaging System Using Two Closely Spaced Loudspeakers Ole Kirkeby, Philip A. Nelson, and Hareo Hamada 387 Two closely spaced dipole loudspeakers can create convincing virtual acoustical images in front of a single listener using a novel system. The proposed arrangement is robust with regard to the listener s head movements and the required signal processing is free of excessive artifacts. An unexpected characteristic of this scheme is that closely spaced loudspeaker configurations produce more accurate imaging than those in which the loudspeakers are more widely spaced.

Relationships among Measures of Speech Intelligibility in Rooms J. S. Bradley 396 Speech intelligibility in rooms is related to both the signal-to-noise ratio and to the acoustical characteristics of the space, each of which can be evaluated separately. Modern measurement techniques are now used to assess the influence of rooms on speech intelligibility by quantifying early-to-late arrival sound ratios and the speech transmission index.

Linear-Phase Crossover Design Using Digital HR Filters . P. Reviriego, Jose Parera, and R. Garcia 406 Where linear-phase response is important, a procedure to design linear- phase all-pass mo-way crossover systems using digital HR filters is presented. It is shown that these linear-phase crossover filter designs exhibit good off-axis response for noncoincident aligned drivers while exhibiting low phase distortion.

ENGINEERING REPORTS Music Signal Segmentation Using Tree-Structured Filter Banks Miljko Bobrek and Daniel B. Koch 413 An 1 ] -stage tree-structured filter bank is described that uses wavelet packet analysis. This novel filter bank is applied to music signal segmentation. Over a wide range of frequencies the filter bank has sufficient frequency resolution for the human ear; and the high-frequency time resolution is equally aurally effective. A new family of quadrature mirror filters with a narrow transition region and a low reconstruction error was implemented to improve selectivity.

STANDARDS AND INFORMATION DOCUMENTS AES17-1998 AES standard method for digital audio engineering — Measurement of digital audio equipment 428 AES Standards Committee News 448 Digital interfaces; preservation of mechanical records; connectors; file exchange; AES-24

FEATURES

The Compact Disc Story Kees A. Schouhamer Immink 458 Audio on Data Networks Francis Rumsey 466 AES Goes Gold Abbie Cohen 470 1998 Directory of Educational Programs ...... (insert)

DEPARTMENTS

Review of Acoustical Patents...... 453 Membership Information 481 News of the Sections .472 In Memoriam 486 Sound Track 474 Audio Engineering Society Application Upcoming Meetings 476 Instructions...... 488 New Products and Developments 476 Sections Contacts Directory 491 Available Literature 479 AES Conventions and Conferences 496 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 46 NUMBER 6 1998 JUNE

CONTENT

PAPERS Direct Feedback Linearization of Nonlinear Loudspeaker Systems Wolfgang Klippel 499 Nonlinear loudspeaker system linearization that uses the control law in the direct form makes audio signal prefiltering in state feedback linearization redundant.The computation complexity is thereby reduced, while requiring fewer loudspeaker parameters than feedback controllers using the integrator-decoupled configuration.

Improving Loudspeaker Performance for Active Noise Control Applications . Steven A. Lane and Robert L. Clark 508 Active noise and acoustic control rely on the performance of actuators, which are most often loudspeakers. The loudspeaker's performance can be enhanced for applications such as control of acoustic enclosures by compensating a loudspeaker with a technique similar to motional feedback. A method is demonstrated that approximates constant volume velocity behavior over the piston mode frequency range of the transducer; which decouples the actuator from the system being controlled. This scheme reduces the impact of the loudspeaker dynamics over the control bandwidth.

ENGINEERING REPORTS Virtual Acoustics, Aeronautics, and Communications Durand R. Begault 520 An optimal approach to auditory display designs to improve flight safety for commercial aircraft operation is reviewed. Spatialized audio techniques and active noise cancellation are the basis for improved communications conditions. The implications of hearing loss among pilots is also considered in this study. The results were obtained from flight simulator studies that were conducted at the NASA Ames Research Center.

Head-Related Transfer Function Modeling in 3-D Sound Systems with Genetic Algorithms Ngai-Man Cheung, Steven Trautmann, and Andrew Horner 531 Practical implementations of three-dimensional (3-D ) audio must take into account a large set of head-related transfer functions ( HRTFs) for different azimuth and elevation angles, since the HRTFs vary as a function of relative sound source locations and subjects' attributes. In this report a genetic algorithm is used to find suitable parameters that represent the individual HRTFs at various azimuth and elevation angles. Experimental results suggest that genetic algorithms provide an effective approximation to this data reduction problem.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News 540 Symbols report erratum; audio-file transfer; synchronization

FEATURES 104th Convention Report, Amsterdam, The Netherlands 546 Exhibitors 562 Program 568 AES 16th International Conference, Rovaniemi, Finland, Call for Papers 601

DEPARTMENTS Review of Acoustical Patents 542 Available Literature 595 News of the Sections 589 Membership Information 596 Sound Track 592 In Memoriam 599 Upcoming Meetings 593 Sections Contacts Directory 603 New Products and Developments 593 AES Conventions and Conferences 608 if

JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 46 NUMBER 7/8 1998 JULY/AUGUST

CONTENT

PAPERS Study of a Fast Method to Calculate Inverse Filters .vHideki Irisawa, Shoji Shimada, Haruhide Hokari, and Shinichi Hosoya 611* In some digital systems it is important to calculate quickly an inverse filter that has a large number of taps. One fast method uses conjugate gradients in the frequency domain. In this paper, a fast method is proposed which calculates only the linear convolution in conjugate gradients by FFT. This proposed method has shown a residual error that is comparable to the Levinson algorithm, but is quicker. Analytic Derivation of Audio PWM Signals and Spectra ...Andreas C. Floros and John N. Mourjopoulos 621 The authors have presented a method that directly maps any arbitrary audio PCM sample value into PWM pulse transition intervals, thereby producing an analytic description of the PWM data stream. The exact spectrum of the PWM signal can also be derived analytically from the PCM audio data. It is claimed that this proposed method has significant advantages over previous methods used for the analysis of PWM conversion artifacts, since it can allow the implementation of efficient compensating strategies for the reduction of the PWM conversion artifacts.

ENGINEERING REPORTS Signal Convolution of Recorded Free-Field Gunshot Sounds Bruce E. Koenig, Shawn M. Hoffman, Hirotaka Nakasone, and Steven D. Beck 634 Gunshot sounds of criminal events are often recorded because of the large number of electronic surveillance and recorder systems. Several gunshot sources and electronic transmission systems were examined , as well as some recording systems, to determine the system's ability to identify the types of gunshots by electronic means, with some interesting results.

COMMUNICATIONS

Subtractive Dither for Internet Audio ...Ben Denckla 654 , Internet audio files popularly use 8-bit word length and low sampling rates.The author proposes a subtractive dithering scheme that is well suited to these formats as well as to the widely available 16-bit playback hardware. A method for automatic detection of these uniquely encoded files is included in the system. ,

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 657 San Francisco meetings; IEEE 1394 ; loudspeakers; connectors

FEATURES 105th Convention Preview, San Francisco 666 Calendar 668 Exhibitors 670 Exhibit Previews 678 15th International Conference, Snekkersten, Copenhagen, Announcement 679 International Sections Directory Updates 709 106th Convention, Munich, Germany, Call for Papers ...... 713

DEPARTMENTS News of the Sections 704 Membership Information ...711 Sound Track . 707 Sections Contacts Directory ...... 715 Available Literature .. 708 AES Conventions and Conferences 720 Upcoming Meetings . 708 :r

-;;f

' : ,:vV ' .y - : . .! . S - jf : - JOURNAL OF THE AUDIO ENGINEERING SOCIETY

: AESAUDIO/ACOUSTICS/APPLICATIONS 's VOLUME 46 NUMBER 9 1998 SEPTEMBER CONTENT PAPERS Theoretical and Experimental Comparison of Three Methods for Compensation of Electrodynamic Transducer Nonlinearity ....Hans Schurer, Cornells H. Slump, and Otto E. Herrmann 723 Nonlinear compensators for electrodynamic loudspeakers are derived based on a simplified nonlinear model and are simulated and implemented on a digital signal processor. The model comprises three nonlinearities: suspension-dependent excursion force factors, stiffness, and self-inductance. Three compensation methods are employed to estimate nonlinear parameters from distortion measurements. The results of these approximations are finally compared and evaluated for their overall utility. Optimization of the Impulse Response Length: Application to Noisy and Highly Reverberant Rooms Laurent Faiget, Claude Legros, and Robert Ruiz 741 The prediction of speech intelligibility uses early-to-late energy arrival ratios. If the measurement is corrupted by external noise the acquisition time's upper limit of integration cannot be fully realized and a new time limit value is then defined as the useful length of the impulse response. Practical results are shown for three highly reverberant rooms. The Air and Wood Modes of the Violin Carleen Maley Hutchins 751 Various violin tone and playing qualities which are based on particular combinations presented by the cavity and body modes are described. The mechanisms underlying the tonal effects of frequency relationships between two strong cavity modes and three important body modes of the violin below 1 kHz are discussed. Differing qualities of practical violin designs are demonstrated for various members of the violin family. Development and Calibration of a Guitar Synthesizer Vesa Valimaki and Tero Tolonen 766 Recent digital waveguide techniques are the basis for synthesizing acoustic guitar tones in an efficient implementation. Enhanced analysis methods are used to calibrate the synthesized model, which is based on digitized tones. Separate parametric second-order resonators that run at a lower sampling rate are used to synthesize the guitar body's lowest resonances.

LETTERS TO THE EDITOR Comments on “Discrete-Element Line Arrays—Their Modeling and Optimization” Earl R. Geddes 779

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News 780 Call for reaffirmations; digital interfaces, synchronization; audio file formats

FEATURES 15th Conference Preview, Snekkersten, Copenhagen, Denmark 786 Calendar 788 Program 788 Registration Form 794 106th Convention, Munich, Germany, Call for Papers .. 816

DEPARTMENTS Review of Acoustical Patents...... 784 Membership Information 811 News of the Sections 796 Audio Engineering Society Membership Sound Track ...... 803 Application Instructions 819 Upcoming Meetings ...... 804 AES Special Publications 822 New Products and Developments 805 Sections Contacts Directory .827 Available Literature 807 AES Conventions and Conferences ...... 832 In Memoriam 810 ...

••• :• • -! ,-r - - JOURNAL OF THE AUDIO ENGINEERING SOCIETY

/ • /APPLICATIONS AUDIO ACOUSTICS" • • _ r AES " ." . ’ VOLUME 46 NUMBER 10 1998 OCTOBER • ' :V- :r

CONTENT >r ... :!- "

President’s Message Marina Bosi 835

PAPERS Three-Dimensional Sound Synthesis Based on Head-Related Transfer Functions ...Ming Zhang, Kah-Chye Tan, and M. H. Er 836 Three-dimensional sound synthesis based on head-related transfer functions ( HRTFs ) is presented using the work of Gardner and Martin of the MIT Media Laboratory. The objective is to refine the HRTFs to effectively exaggerate the perceptual differences for sounds arriving from different directions and to emphasize the pinnae effects. Tape Flux Measurement Revisited ...... John G. (Jay) McKnight, Benito E. Cortez, and Jeffrey A. McKnight 845 Two methods for determining tape flux density are described and found to be in very close agreement. Measurement of earlier German calibration tapes by the two current methods indicates their fluxivity % their , or 288 nWb/m rather than 320 nWh/m. This paper contains to be 10 lower than stated value ^ extensive documentary support for the experimental procedures employed in making the ' " v ' • *••• . .. • v, • . < .. measurements and their results - ^^ . . Determining the Magnetization of Magnetic Tape (Reprint) Otto Schmidbauer 859 The first English translation of the classic 1957 work on tape flux measurement. ( Editorially updated by John G. McKnight. ) , Method for Measuring the Absolute Magnitude and Frequency Response of the Flux on Magnetic Tape (Reprint) DIN Standard 865 German Standard DIN 45 502, first published in 1957, was the original standard for measuring tape flux. ( Translation by Brigitte McKnight; edited by John G. McKnight.)

ENGINEERING REPORTS Modeling Acoustic Wind Instruments with Contiguous Group Synthesis ...... Andrew Horner and Lydia Ayers 868 Wind instruments are synthesized using a single spectrum to describe each part of an instrument's range. The desired articulation is controlled by predefined amplitude envelopes, which also provide increased tonal brightness with increasing amplitude. The model shows promise in designing new windlike instruments, since the individual parameters can be manipulated directly.

STANDARDS AND INFORMATION DOCUMENTS AES5-1998 AES Recommended Practice for Professional Digital Audio — Preferred Sampling Frequencies for Applications Employing Pulse-Code Modulation 880

AES Standards Committee News . .. 886 Mechanical disc restoration, listening tests, digital audio

FEATURES AES Officers 1998/1999...... 890 Review of Society’s Sustaining Members ...... 892 AES News: Student Delegate Assembly Elects Officers 915

DEPARTMENTS News of the Sections ...... 916 Membership Information v.i.:925 - * Sound Track m m 920 In Memoriam -: 928 New Products and Developments 921 AES Annual Report 930 Upcoming Meetings 922 Sections Contacts Directory ...... 931 Available Literature 923 AES Conventions and Conferences 936

,r”’: s-; : JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 46 NUMBER 11 1998 NOVEMBER CONTENT PAPERS Adaptive Nonlinear Control of Loudspeaker Systems Wolfgang J. Klippel 939 Inverse nonlinear processing of the electrical driving signal can compensate for signal distortions caused by loudspeaker nonlinearities. Optimal performance requires an adaptive system to compensate for loudspeaker parameter variations which are related to the effects of heating and aging during operation. The author presents a. novel technique for direct updating of the control parameters which makes separate system identification redundant. Two Decades of Diffusor Design and Development, Part 1: Applications and Design Peter D'Antonio and Trevor Cox 955 In the past two decades there has been a large increase in the design knowledge of sound diffusors used in architectural acoustics. The ability to measure, quantify, and predict performance of diffusors has evolved, while the addition of new surface types has expanded the acoustician's range of T r'v materials. This paper reviews the documents in the historical development of sound diffusing surfaces that have predictable performance attributes, and illustrates their applications. Part 2 of the paper will review methods for predicting, measuring, and characterizing the quality of scatter produced by

these surfaces. ""' V Frequency-Domain Equalization of Audio Systems Using Digital Filters, Part 1: Basics of Filter Design Alexander Potchinkov 977 Design basics of digital filters, which are used to equalize frequency domain characteristics, are reviewed. These principles are applied to the magnitude and phase responses, which are parts of combined analog and digital audio signal processing. In Part I of this two-part paper, fundamental design principles are studied with reference to various design concepts.

ENGINEERING REPORTS A Method of Reproducing Concert Hall Sounds by “Loudspeaker Walls” Kazuho Ono, Setsu Komiyama, and Katsumi Nakabayashi 988 A novel concert hall sound simulation system is proposed that has its listening room equipped with “loudspeaker walls.” These unusual walls have a large number of small loudspeakers (more than 300 ) mounted on them. In the signal driving chain many reverberant sounds are generated using a block shift method. These uncorrelated signals are then reproduced by the wall-mounted loudspeakers. In subjective listening tests it was found that the loudspeaker walls provide a very wide uniform listening area within the room.

STANDARDS AND INFORMATION DOCUMENTS DRAFT AES3-1992 Amendment 3-xxxx to AES Recommended practice for digital audio engineering — Serial transmission format for two-channel linearly represented digital audio data (insert) AES Standards Committee News 996 Status of projects

FEATURES 105th Convention Report, San Francisco 1004 Exhibitors 1020 Program 1024 AES News: Hamm Becomes Eastern Region VP 1052

DEPARTMENTS News of the Sections 1047 Membership Information 1057 Upcoming Meetings 1050 In Memoriam 1060 Sound Track 1051 AES Special Publications , 1062 New Products and Developments 1053 Sections Contacts Directory 1067 Available Literature 1055 AES Conventions and Conferences 1072 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 46 NUMBER 12 1998 DECEMBER CONTENT PAPERS Two Decades of Sound Diffusor Design and Development, Part 2: Prediction, Measurement, and Characterization Peter D'Antonio and Trevor Cox 1075 Methods for measuring and predicting the scattered polar sound distribution by using boundary- element methods and maximum-length-sequence stimuli are reviewed in this, the second part of a paper on diffusors. An extensive list of references is included as well as a glossary of acoustical terms. The supporting illustrations give the reader a broad outline of the comprehensive methods used to make these measurements of diffusor performance. Frequency-Domain Equalization of Audio Systems Using Digital Filters, Part 2: Examples of Equalization Alexander Potchinkov 1092 Numerical examples of digital-domain equalizers are presented in this, the second half of a two-paper presentation. The author has shown the advantages that accrue from equalization by digital filter means. Some related subjects are reviewed which include efficient multirate filter realization, parametric modeling, and the comparison of recursive and nonrecursive digital filters. Orthogonal Sequence Modulated Phase Reflection Gratings for Wide-Band Diffusion ...James A. S. Angus and Claire I. McManmon 1109 A technique, which uses two basic quadratic residue diffusors of different lengths, can remove the lobe narrowing that normally occurs when two diffusors are concatenated. An extended frequency performance range and a smoother diffusion response are achieved using the authors' composite design criteria. By employing these composite design sequences, the diffusion performance approaches that of a single sequence diffusor. ENGINEERING REPORTS Comparison of Two Methods for Measurement of Horn Input Impedance Hans Schurer, Peter Annema, Hans-Elias de Bree, Cornelis H. Slump, and Otto E. Herrmann 1119 After comparing the acoustic horn impedance by two discrete measurement methods, the authors have concluded that horn impedance measurement is performed faster, easier, and more accurately by direct measurement using a microflown. It is shown that this is a valuable tool by which horns and other acoustical structures can be approximated and that their parameters can be tuned easily to obtain correspondence between measurement and model. STANDARDS AND INFORMATION DOCUMENTS DRAFT REVISED AES24-1-xxxx AES Standard for sound system control - Application protocol for controlling and monitoring audio devices via digital data networks - Part 1: Principles, formats, and basic procedures ... (insert) AES Standards Committee News 1126 Internet audio quality; forensic audio; loudspeaker specification; 96 kHz digital; audio file format FEATURES AES 15th International Conference Report, Copenhagen, Denmark 1134 1998/1999 AES International Sections Directory 1142 Call for Nominations for Awards 1171 Call for Nominations for Board of Governors 1172 AES 9th Tokyo Regional Convention, Call for Papers... 1176 AES 17th International Conference, Florence, Italy, Call for Papers 1178 AES 107th Convention, New York, Call for Papers 1180 Bylaws: Audio Engineering Society, Inc 1182 Index to Volume 46 1186 DEPARTMENTS News of the Sections 1164 Membership Information 1173 Sound Track 1168 In Memoriam 1175 New Products and Developments 1169 Audio Engineering Society Membership Upcoming Meetings 1169 Application Instructions 1197 Available Literature 1170 AES Conventions and Conferences 1200 : X -7 * : f ' - * * ; ' /: . ± . .... : ! .. te ' . "7,y. ' M

; i - 7. vir JOURNAL OF THE —-: ..V , AUDIO ENGINEERING SOCIETY

* m * " ’ • ‘ ‘ v /APPLICATIONS: ‘ *’ ’ / x ACOUSTICS: , AUDiO . . \ .. .: : . A . . = - A - '-

1 2 ! ’’ 1999 JANUARY/FEBRUARY VOLUME 47 NUMBER / v :i. A y, - ! - •u - X:. - " ' ' : ‘ Ht v:.. 'i = . 1 A.: : •’!L v“\? ' , . ' ’ U " i Vi : ... Ki = - ' V - " iv:\ • V : i • •’• V - « - • ' : ; ' ' : V r. ''' ' - A , - . - A ,, • ,; =: - -

: •?.. CONTENT

' : 'vl • .. : 'v ! 1 k fc : = - " " • a 7 - :: - * : = !? • > ?V A: - - ! :’ * .jf . X ... •&:_ ii. ! :< I:: ;; .... - . • .... PAPERS • - v . > ' > 7-.V The Acoustic Lever Loudspeaker Enclosure Earl R. Geddes 3 A new system for substantially improving loudspeaker system efficiency is presented. The loudspeaker '

efficiency : . driver’s output is coupled to resonant chambers that effectively raise the acoustical A ¥; further increase in the efficiency is achieved by mechanically coupling the compliant members of the wr

:: . , overall • % .. 7 ., limiting of acoustical ‘ coupled chambers. The trade off for the improved efficiency is a the = - " - I f ;. bandwidth. ^ •:Vv‘

Comparison of Loudspeaker Equalization Methods Based on DSP Techniques

c: «•..» f • » .....V.....Matti Karjalainen, Esa Piiriia, Anttl Jarvinen, and Jyri Huopaniemi 14 Digital filters to equalize loudspeaker response are used in this studycAnew equalization principle which employs warped filters is described. The warped filter designs have the advantage over traditional designs of a reduced filter order with improved numerical robustness. The disadvantage is the higher computational complexity of the warped structure, depending in which hardware or software environment the warped filter is used.

H .,. ' ' ' i;. S . ! ...... v . .. A ^ COMMUNICATIONS /••g: T . . Eiectronic Damping for Dynamic Drivers in Vented Enclosures T. S. Hsu and K. A. Poornima 32 Loudspeaker voice coils when driven at high power levels experience considerable heating which results in elevated voice coil resistance and subsequent damping loss. The authors have restored the

: \ Vi;.: • . loudspeaker - VS * ..:;; damping loss by introducing velocity feedback to the electromechanical system The x : * system damping can then be maintained at a constant value, independent of the changes in - driver " Ns::. by current drive ‘ the voice coil’s dc resistance, employing . ' s /

STANDARDS AND INFORMATION DOCUMENTS

K J< •. r. ,

' - %. .. . 7 • AES Standards Committee News...... '•* • « * * * *» :!» «r 39 Patch panel connectors; audio in 1394; acoustical diffusion ..

FEATURES

: 16th Conference Preview, Rovaniemi, Finland ...... i. . .,iV.. 42 ... ' . ' . .... • . s. _ : .: . - - - - - " -s :,7; v::... Calendar ...... ••••• ...... 44 ..... • s - ••.... : . s s - - . . i » : » » . . . iV , * * * 46 Program ...... • •• *• ...... -. - .. A- ‘' ” . Registration Form 53

s- 'is - ' DEPARTMENTS i: ’ -s;;:.. - .. - ' S ::: : - - . * * , « ii ' ' News of the Sections •> •V* ...... 54 Membership Information..- .... ****!;.* * := = = = :, - = •:i. Upcoming Meetings ...... 60 AES Special Publications .. ^ .:. .;;.69 Sound Track 60 Sections Contacts Directory 74 . . • . New Products and Developments ...... 62 AES Conventions and Conferences 80 i' • - -- ? Available Literature .... * ** ...... * •’‘* ’ :.64 !! '7 H . • ; % - - J. ‘i - - i ' ,. :. :a . . -h - a. .. ' : : 7/7 V ! :• --7. - .. •a

' ' . -. xi: 7 , 7.7 ; : : < ,! ' - ?* i . ? . * r- . . ri a ' U r : - : >\ ' yi - 7"7 ' - ' ' • : r • - 7 !' V »> = ? = : *Z.' : . . • xx : 1 ^ = ; • nv-. : ! ' : : " V A: T • i ' : - > i -a: JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 47 NUMBER 3 1999 MARCH CONTENT PAPERS Evaluation of Artificial Heads in Listening Tests Henrik Moller, Dorte Hammershoi, Clemen Boje Jensen, and Michael Friis Sorensen 83 The subjects in this presentation listened to and compared real sound fields to artificial-head recordings of the same sound field. This study was designed to evaluate comparative localization performances of artificial heads. The results of listeners' localization performance tests, when comparing artificial-head recordings to those of the real sound fields, resulted in an increased number of errors. The results obtained when using some of the artificial heads in this study also showed an increase in confusion of directionality perception outside the median plane. The overall conclusion indicated the need for an improved artificial-head design.

Modeling Piano Tones with Group Synthesis Kathy Lee and Andrew Horner 101 Synthesizing piano sound is a difficult task because it is subject to spectral changes during its long decay. Group synthesis, a special case of wavetahle synthesis, has been adapted by the authors to efficiently model piano sounds. It requires about one half the data allocation required by additive synthesis. This solution is computationally about twice as fast as additive synthesis. Plucked strings, percussive mallet sounds, and bell tones are good future test cases for this synthesis model.

ENGINEERING REPORTS Noise Relations for Parallel Connected Transistors W. Marshall Leach, Jr. 112 The noise performance of an amplifier's input stage consisting of a number of parallel connected semiconductor devices is examined. The resultant equivalent input voltage noise is measured while keeping the bias current constant and varying the number of input devices. The result is then compared to the noise while holding the bias current per device constant. The findings of this study contribute significantly to the understanding of low-noise amplifier input system designs.

Acoustics of Russian Classical Opera Houses Michael Lannie and Leonid Makrinenko 119 Acoustic problems attendant to Russian theaters, which were built in classical style, having horseshoe-shaped floor plans with several rows of balconies, were investigated. Reverberation times of these old halls were measured under varying conditions and the results analyzed. The goal of this investigation was to make suggestions for renovating the old halls to improve their acoustical performance. This study also provides acoustic guidelines for the design of future performance halls.

STANDARDS AND INFORMATION DOCUMENTS AES3-1992 Amendments to AES Recommended practice for digital audio engineering — Serial transmission format for two-channel linearly represented digital audio data .. 130 Amendment 1 131 Amendment 2 . 135 Amendment 3 137 AES Standards Committee News 143 AES24; connector database; loudspeaker measurement ; room acoustics; 1394 synchronization; AES3 in MPEG; restoration; AES3 synchronization; digital interfaced microphones; grounding and EMC

FEATURES 106th Convention Preview, Munich, Germany 150 Calendar 152 Exhibitors 154 Exhibit Previews . 159 The Future of Audio Recording Kees A. Schouhamer Immink 171 AES News: AES Presents White Paper on Audio Quality for Internet 179 Education News 180

DEPARTMENTS Upcoming Meetings 172 In Memoriam 189 News of the Sections 173 Audio Engineering Society Membership Sound Track 181 Application Instructions 191 Available Literature.. 182 Sections Contacts Directory 194 Membership Information 185 AES Conventions and Conferences 200 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 47 NUMBER 4 1999 APRIL CONTENT PAPERS Analyzing Virtual Sound Source Attributes Using a Binaural Auditory Model .Ville Pulkki, Matti Karjalainen, and Jyri Huopaniemi 203 A computational model of auditory perception is used to evaluate virtual sound sources that were created by different techniques. The spatial attributes are discussed relative to the auditory cues of real and virtual sound sources. The authors found good computational agreement with empirical listening results based on the model's prediction of known listening phenomena in loudspeaker listening environments. Objective and Subjective Evaluation of Head-Related Transfer Function Filter Design ..Jyri Huopaniemi,Nick Zacharov, and Matti Karjalainen 218 The auditory perception point of view in this study is the basis for binaural auditory modeling as applied to the head-related transfer function. The authors present applicable perceptually valid filter design techniques and listening test results for localization and timbre degradation. The stated conclusion is that filter design methods for 3-D sound can gain considerable efficiency when a non- uniform- auditory frequency resolution representing the human ear is used. The required filter length for high-quality 3-D sound synthesis is also dependent on the incident angle of the incoming sound. Implementation of a New Algorithm Using the STFT with Variable Frequency Resolution for the Time-Frequency Auditory Model Hyuk Jeong and Jeong-Guon Ih 240 A new algorithm is proposed for the time frequency analysis of unsteady sound signals whose objective is the consideration of the human auditory processing system. The system is called the VFR-STFT ( short-time Fourier transform with variable frequency resolution). The frequency resolution is adjusted to the variation of filtered frequency ranges by using a downsampling technique. This system can be considered as a useful time-frequency analysis method to describe and analyze auditory related subjects. Tone Bursts for the Objective and Subjective Evaluation of Loudspeaker Frequency Response In Ordinary Rooms Allan Rosenheck and Kurt Heutschi 252 Controlled-length tone bursts are proposed for evaluating low-frequency performance of loudspeakers in reverberant fields of conventional rooms. This method offers a practical advantage over other conventional tests and provides a rapid, subjective evaluation for each frequency band of the system under test.

STANDARDS AND INFORMATION DOCUMENTS AES24-1-1999 (Revision of AES24-1-1995) AES standard for sound system control — Application protocol for controlling and monitoring audio devices via digital data networks — Part 1: Principles, formats, and basic procedures ..... 256

AES Standards Committee News 298 106th Convention meetings; digitally interfaced microphones; sound system control

FEATURES AESWP-10G1 AES White Paper: Networking Audio and Music Using Internet2 and Next- Generation Internet Capabilities Robin Bargar, Steve Church, Akira Fukuda, James Grunke, Douglas Keislar, Bob Moses, Ben Novak, Bruce Pennycook, Zack Settel, John Strawn, Phil Wiser, and Wieslaw Woszczyk 300 Updates and Corrections to the 1998/1999 Internationa] Sections Directory 317 Updates to Review of Society’s Sustaining Members 322 DEPARTMENTS

News of the Sections ...... 311 In Memoriam ...... ; 326 Sound Track ...... 315 Audio Engineering Society Membership Upcoming Meetings 318 Application Instructions 327 New Products and Developments 319 Sections Contacts Directory ...... 330 „ Available Literature .. v. 320 AES Conventions and Conferences ,*:*•*.' 336 Membership Information. 324 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 47 NUMBER 5 1999 MAY CONTENT PAPERS Performance of the Genetic Annealing Algorithm in DFM Synthesis of Dynamic Musical

Sound Samples S. .M. Lim and B. T. G. Tan 339 A qualitative analysis using dynamic musical sound sample parameter optimization is employed to assess the performance of a genetic annealing algorithm (GAA ) in the double frequency modulation ( DFM ) parameter optimization problem. The dynamic musical sound samples are synthesized using DFM synthesis techniques. The GAA optimizes the solution by plotting the solution spaces of the one- DFM equation for all samples. A recycling process has been proposed to improve the efficiency of the GAA process.

ENGINEERING REPORTS The Influence of Video Quality on Perceived Audio Quality and Vice Versa John G. Beerends and Frank E. de Caluwe 355 A unique set of listening and observation tests was performed to determine the influence of audio on perceived video quality; and conversely, the influence of video on perceived audio quality. The test subjects indicated a relatively small effect of audio quality on the perceived video quality presentation, while the video effect had a largerinfluence on the perceived audio quality peiformance. It was found that the video quality dominates the overall perceived audiovisual quality. A Novel Intensimetric Technique for Monitoring the Radiative Properties of Sound Fields .Nicola Prodi and Domenico Stanzial 363 The new energy-descriptive measurement of sound fields is focused on the development and application of the related intensimetric technique. Experimental results of three specific measurement applications in room acoustics, musical acoustics, and noise control, illustrate that this technique is exceptionally helpful for monitoring the radiative properties of sound fields. Special attention was given throughout these experiments to the measurement errors of the newly defined component called “oscillating intensity,” which was shown to be almost completely insensitive to phase errors.

Ab Initio Model for Triode Tube A. Kashuba 373 Mechanical design and construction characteristics of specific vacuum tubes are used to develop the 3/2 law model for vacuum tubes operating with negative grid bias. The plate characteristics are accurately described by the 3/2-scaling invariant, which is derived from the tube’s fundamental physical characteristics and internal field configurations. It is proposed that this scheme can be a replacement for the Child-Langmuir law for triodes, since this model was developed in terms of basic mathematical functions.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News 378 Preservation of audio recordings

FEATURES 17th Conference Preview, Florence, Italy ...... 386 Calendar . 388 Program 390 Registration Form 397 107th Convention, New York, USA, Call for Workshops Participants 408 108th Convention, Paris, France, Call for Papers 416 9th Regional Convention Preview, Tokyo, Japan (insert)

DEPARTMENTS Review of Acoustical Patents 383 Membership Information...... 411 News of the Sections 400 Upcoming Meetings 412 Sound Track 405 In Memoriam 415 New Products and Developments .....406 Sections Contacts Directory ...... 418 Available Literature 409 AES Conventions and Conferences 424 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 47 NUMBER 6 1999 JUNE

CONTENT

PAPERS Air-Related Harmonic and Intermodulation Distortion in Large Sound Systems Eugene Czerwinski, Alexander Voishvillo, Sergei Alexandrov, and Alexander Terekhov 427 A series of measurements was made on two loudspeaker arrays which consisted of similar horn drivers to determine nonlinear and intermodulation distortion attributable to air propagation at various sound pressure levels, frequencies, and distances. These measurements indicated that the level of air-based nonlinear distortion could significantly exceed the distortion generated within a single horn. The experiments also showed that multiple high-level horn arrays can generate nonlinearity distortion inversely to their spacing. It is further suggested that current digital distortion correction schemes for single-system horn arrays do not address the resultant nonlinear air distortion generated when using multiple array systems.

Time-Domain Nonlinear Modeling of Practical Electroacoustic Transducers S. M. Potirakis, G. E. Alexakis, M. C. Tsilis, and P. J. Xenitidis 447 The authors investigated published time domain modeling techniques that were used in the derivation of nonlinear loudspeaker models. No special testing signals or expensive test equipment were used for the acquisition of input-output data. The modeling technique that produced the most accurate, adequate, and economical loudspeaker model was a combination of fuzzy logic and classic NARMAX procedures.

A Study on the Derivation of Transfer Functions for Sound Image Localization Using Stereo Earphones Shohei Yano, Haruhide Hokari, Shoji Shimada, and Hideki Irisawa 469 Seven algorithms were examined for use with stereo headphones to evaluate their sound localization transfer function ( SLTF ) effectiveness. Each transfer function was derived using the impulse response measuring method. Two performance attributes were used to evaluate the effectiveness of each SLTF function: the calculation time and the subjective assessment score. The results of the tests showed two of the seven transfer functions resulted in superior performance over the remaining five.

STANDARDS AND INFORMATION DOCUMENTS DRAFT AES33-xxx AES standard for audio interconnections — Database of multiple-program connection configurations (insert)

AES Standards Bulletin: Coding for transparent cascading of compressed audio 479

AES Standards Committee News.... . 480 Digital audio alignment levels; digital file exchange; digital interface microphones; Internet audio quality

FEATURES 16th Conference Report, Rovaniemi, Finland 484 106th Convention Report, Munich, Germany, 492 Exhibitors 508 Program 512 108th Convention, Paris, France, Call for Papers 552 9th Regional Convention Preview, Tokyo, Japan (insert)

DEPARTMENTS News of the Sections 536 Membership Information 545 Upcoming Meetings 540 In Memoriam 548 Sound Track 541 Sections Contacts Directory 554 New Products and Developments 543 AES Conventions and Conferences 560 Available Literature 544 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 47 NUMBER 7/8 1999 JULY/AUGUST CONTENT PAPERS Controlled Subjective Assessments of Two-to-Five-Channel Surround Sound Processing Algorithms Francis Rumsey 563 Several algorithms for expanding several types of two-channel stereo programs to five-channel surround sound were evaluated by listening panels at the Research and Development Department of the British Broadcasting Corporation. It was considered important to know what effect these processes might have on the quality of sound reproduction and if listeners judged the processed versions superior to the original two-channel program material. Although there were no definitive, single-answer conclusions to these tests, there were some additional unanswered questions raised concerning the use of dipole loudspeakers and comparison listening tests between discrete five- i y :::V. channel programs and two-to-five expanded program materials.

Digital Filter Design for Inversion Problems in Sound Reproduction ...... Ole Kirkeby and Philip A. Nelson 583 The authors studied digital filters that were designed to eliminate the influence of a loudspeaker's room response, and the subsequent excessive boost of frequencies that occurred just below the Nyquist frequency. Designing digital filters for a multichannel virtual source imaging system . t I V ? . W' presents a similar problem. A time-domain filter design method can be used for efficient deconvolution of single and multichannel systems.

ENGINEERING REPORTS Building a Plane-Wave Tube: Experimental and Theoretical Aspects ..Roberto Magalotti, Carlo Zuccatti, and Paolo Pasini 596 The primary purpose of this report is to describe the building and testing of a plane-wave tube for measuring compression drivers in an audio laboratory. A new method for testing the tube for undesired reflections was devised, with and without sound absorbing materials. The experimental results show good agreement with the predicted behavior outlined in the AES document on plane-wave tubes, and confirm the predictions on usable bandwidth limits. - :”-f •:

• .::: Audio Sound Reproduction Based on Nonlinear Interaction of Acoustic Waves Dong Weiguo and Wu Qunli 602 The authors investigated audio sound reproduction based on nonlinear interaction of acoustic waves in a duct. Special emphasis was given to the sum and difference frequencies generated by the nonlinear behavior of the acoustic waves. When the frequencies of the two primary waves were increased to the ultrasonic spectrum, the audible resultant sound was attributable to the difference .. | .. wave. This finding suggested the possibility of audio sound reproduction which uses the nonlinear interaction attributes of two ultrasonic waves.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News;.. 607 Standards groups meeting at the 107th convention; listening tests; preservation of recorded tapes; digital measurements; mechanical disc reproduction; digital synchronization

FEATURES 107th Convention Preview, New York 612 Calendar 614 Exhibitors 616 Exhibit Previews 624

v: -V DEPARTMENTS * News of the Sections 654 Membership Information...... 663 Upcoming Meetings . .658 Sections Contacts Directory 666 Sound Track . 659 AES Conventions and Conferences 672 Available Literature 660 ‘rr/ ^T- y :S.. . : 'i «-w.' ¥ If fJS JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 47 NUMBER 9 1999 SEPTEMBER CONTENT PAPERS Creating Interactive Virtual Acoustic Environments .Lauri Savioja, Jyri Huopaniemi, Tapio Lokki, and Riitta Vaananen 675 The modeling techniques for the three major components of real-time auralization, namely the sound source, the room acoustics, and the listener, are presented extensively by the authors. They have developed a software system, DIVA, for producing virtual audio-visual performances in real time. A wide range of future applications for this software is proposed, such as computer games, multimedia, virtual-reality applications, and architectural acoustic designs. ENGINEERING REPORTS

MATLAB Program for Loudspeaker Equalization and Crossover Design M. O. J. Hawksford 706 A digital design filter program has been written in the MATLAB environment. The filter design uses time-domain impulse response data at its input and generates filter coefficients for both FIR and HR implementations. Comprehensive display options are incorporated in the software which include minimum phase processing. Consideration is also given to designs for specular and diffuse loudspeakers.

A Real-Time Speech-Music Discriminator Ronald M. Aarts and Robert Toonen Dekkers 720 A unique real-time discriminator has been designed that automatically detects the differences between speech and music signals and is not gender sensitive. Its operational reliability has been tested on a series of modern languages as well as in various types of musical and instrumental combinations. The systems authors state that their method is extremely reliable with virtually zero false alarm probability. The Use of Airborne Ultrasonics for Generating Audible Sound Beams F. Joseph Pompei 726 Audible sound is created from ultrasound sources that use the nonlinear characteristics of air. The resulting sound from a wide-band parametric acoustical array is extremely directional and beamlike. This field of acoustical activity is relatively new and the author has included a discussion of future challenges to this area of ultrasound applications.

STANDARDS AND INFORMATION DOCUMENTS DRAFT REVISED AES7-xxxx AES standard for the preservation and restoration of audio recording — Method of measuring recorded fluxivity of magnetic sound records at medium wavelengths...... (insert)

DRAFT AES31-3-xxxx AES standard for network and file transfer of audio Audio-file transfer and exchange — Part 3: Simple project interchange (insert)

DRAFT AES3-1992 Amendment-4-xxxx to AES Recommended practice for digital audio engineering — Serial transmission format for two-channel linearly represented digital audio data (insert)

AES Standards Committee News...... 732 IEEE 1394; archival transfers

FEATURES Fundamentals of Modern Audio Measurement Richard C. Cabot 738 Updates and Corrections to the 1998/1999 International Sections Directory 772 DEPARTMENTS

Review of Acoustical Patents...... 735 Available Literature 771 News of the Sections ...... 763 Membership Information.. 1...774 Sound Track ... 767 In Memorium 776 Upcoming Meetings 769 Sections Contacts Directory 778 New Products and Developments 769 AES Conventions and Conferences 784 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 47 NUMBER 10 1999 OCTOBER • ::: . CONTENT - : .

President’s Message,...... David P. Robinson 787 PAPERS Attack and Release Time Constants in RMS-Based Feedback Compressors Fred Floru 788 Mathematical models for feedback and feedforward compressors are developed in this paper. The author analyzes the transfer functions for a linear-output rms detector in conjunction with a linearly controlled VCA ( linear-domain compressor ) and a logarithmic-output rms detector in conjunction with an exponentially controlled VCA ( log-domain compressor ). It is shown that both transfer functions are equivalent. Comparisons between feedback and feedforward configurations are discussed to optimize their attributes for specific applications. ENGINEERING REPORTS Applications of Digital Watermarking Technology in Audio Signals ....L..L...... Changsheng Xu, Jiankang Wu, Qibin Sun, and Kai Xin 805 Protection of audio intellectual properties has become a subject of great concern in the digital age of audio. Audio watermarking techniques are compared and discussed relative to the heed for robustness and adaptability to the program material in which the watermark is embedded, and its transparency within the program content The authors propose a content-adaptive multiple-echo hopping technique to embed the watermark into audio signals, which is claimed to be superior to many of the current systems. It is anticipated that reliable watermarking will become even more important as digital techniques expand. Modeling the Woodstock Gamelan for Synthesis Lydia Ayers and Andrew Horner 813 A Csound implementation for synthesizing Woodstock gamelan tones has been developed. This synthesized model produces tones that are very close to the original instrument's tones, according to .. listening tests. It can also produce attractive related timbres with simple changes to the model parameters. Virtual Acoustic Displays for Teleconferencing: Intelligibility Advantage for “Telephone Grade” Audio Durand R. Begault 824 The advantages of virtual acoustic (3-D audio ) displays to achieve spatial separation for stereo headphone users have been investigated by the author. The technique separates multiple communication channels by placing each sound source at a unique virtual audio position, thereby simulating and exploiting the “cocktailparty’” effect. This approach increases the intelligibility of audio signals against noise in an “unmasking ” process. STANDARDS AND INFORMATION DOCUMENTS AES33-1999 AES standard — For audio internconnections — Database of multiple-program connection configurations : 829 DRAFT AES43-xxxx AES standard for forensic audio — Criteria for the authentication of analog audio tape recordings (insert) AES Standards Committee News ...... 835 Loudspeaker modeling and measurement FEATURES 9th Tokyo Regional Convention Report ... 838 Exhibitors ...... 848 Program 849 .ii AES Officers 1999/2000...... 856 Review of Society’s Sustaining Members 861 Call for Nominations for Awards...... 888 DEPARTMENTS News of the Sections ...... 878 In Memoriam 893 Sound Track ...... 882 AES Annual Report ViW-..-. ,...894 Upcoming Meetings ... L 883 Audio Engineering Society Membership New Products and Developments 884 Application Instructions 895 Available Literature 885 Sections Contacts Directory 898 Membership Information ...... 889 AES Conventions and Conferences ...... 904 : ""v-.-.-:..

... JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 47 NUMBER 11 1999 NOVEMBER CONTENT PAPERS Errors In MLS Measurements Caused by Time Variance in Acoustic Systems U. Peter Svensson and Johan L. Nielsen 907 The effects of both interperiodic and intraperiodic time variance on MLS acoustical measurement were studied using time-stretching and an analogy with delay modulation as models. Practical results of this study show that both intra- and. interperiodical time variances can be detected in a measured impulse response, and the effects of averaging can be quantified.

New Phase-Vocoder Techniques for Real-Time Pitch Shifting, Chorusing, Harmonizing, and Other Exotic Audio Modifications Jean Laroche and Mark Dolson 928 The phase vocoder, a well understood tool for time scaling and pitch shifting, has had improvements proposed that reduce artifacts commonly encountered when signals are time expanded by large factors. This paper focuses primarily on pitch-scale change of speech and audio signals. Two alternative methods are presented which significantly reduce the computational complexity and cost, while enabling chorusing , harmonizing, partial stretching, and frequency inversions.

ENGINEERING REPORTS Dependence of Subject and Measurement Position in Binaural Signal Acquisition . V. Ralph Algazi, Carlos Avendano, and Dennis Thompson 937 Extensive acoustical source location measurements were performed along the ear canal of a KEMAR mannequin and two human subjects. The goal was to present a detailed evaluation of a recording microphone's positions along the ear canal of the head-related transfer functions ( HRTFs) under blocked and unblocked conditions. It was shown that there are conditions under which the magnitude transfer function from the HRTF acquisition position to the eardrum is essentially independent of the source location. A Worst-Case Analysis for Analog-Quality (Alias-Free) Digital Dynamics Processing Dan Mapes-Riordan 948 Digital dynamics signal processing generates significant and undesired distortion products; these are aliases that occur below 20 kHz. To uncover the presence of these products in typical digital audio systems, a closely spaced pair of sinusoids is slowly swept in frequency, and the aliasing products are observed. It is suggested that there is a correlation between the amount of aliasing distortion in digital dynamics processors and their perceived sonic qualities.

STANDARDS AND INFORMATION DOCUMENTS DRAFT AES-6id-xxxx AES Standard for Information document for digital audio — Personal computer audio quality measurements (insert) AES Standards Committee News 953 Digital interfaces, audio-file transfer, IEEE 1394, microphones, forensic audio

FEATURES 17th Conference Report, Florence, Italy 962 107th Convention Report, New York 970 Exhibitors 986 Program 990 Digital Audio and the Challenge of the Internet RogerLagadec 1013 AES News: Real-time Multichannel Audio over the Internet 1022 Education News 1023 DEPARTMENTS

Review of Acoustical Patents 959 New Products and Developments... 1028 News of the Sections 1018 Membership Information 1030 Upcoming Meetings 1021 In Memoriam 1033 Sound Track 1025 Sections Contacts Directory 1034 Available Literature 1026 AES Conventions and Conferences 1040 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 47 NUMBER 12 1999 DECEMBER CONTENT PAPERS Wigner Distribution Representation and Analysis of Audio Signals: An Illustrated Tutorial Review Douglas Preis and Voula Chris Georgopoulos 1043 A visual display of quantitative information about how a signal's energy is distributed in both time and frequency is presented by the Wigner distribution. This display embodies the two fundamentally important concepts of Fourier and. time-domain analysis into a comprehensive display. A substantial amount of practical insight, understanding, and interpretive skill can be gained by carefully examining the wide variety of computed Wigner distributions illustrated in this paper. ENGINEERING REPORTS Relationships between Noise Shaping and Nested Differentiating Feedback Loops J. Vanderkooy and M. O. J. Hawksford 1054 The use of heavy feedback is studied in two different topologies: multiple-order noise shaping and nested differentiating feedback loops. Both topologies have similar loop gains and stability considerations, but have different implied circuit environments and areas of application. This tutorial paper helps in understanding the application of large feedback amounts used to control noise or distortion at baseband frequencies. A Unified Fast Algorithm for Cosine Modulated Filter Banks in Current Audio Coding Standards Chi-Min Liu and Wen-Chieh Lee 1061 Modern audio compression coding standards have adopted various forms of the cosine modulated filter bank ( CMFB) for compression. These modulated cosine transforms (MCTs) can be resolved into two modules: the permutation and discrete cosine transform ( DCT ). The derived DCTs are of three types. This paper proposes a fast computing algorithm to compute uniformly all three types of the discrete cosine transforms. Synthesis Modeling of the Chinese Dizi, Bawu, and Sheng , . Andrew Horner, Lydia Ayers, and Daniel Law 1076 The spectral properties of the Chinese dizi, bawu, and sheng, and how they differ from their Western counterparts, are described in this paper. A group additive synthesis model has been developed for these three instruments using wavetables, together with their Csound implementations. The authors state the listening tests show the models are nearly indistinguishable from the original instruments’ tones, confirming the effectiveness of the synthesized matches. STANDARDS AND INFORMATION DOCUMENTS AES3-1992 Amendment 4-1999 Amendment 4 to AES Recommended practice for digital audio engineering — Serial transmission format for two-channei linearly represented digital audio data.. 1088 AES Standards Bulletin: Formation of the SC-02-02-D task group on extending AES10-1991 (MADI) to higher sampling frequencies 1091 AES Standards Committee News.... 1092 Preservation transfers; optical media life; loudspeakers; listening tests; EMC practices; Internet music FEATURES 108th Convention Preview, Paris 1098 Calendar 1100 Exhibitors 1102 Exhibit Previews 1106 1999/2000 AES International Sections Directory ... 1120 109th Convention, Los Angeles, Call for Papers 1156 Call for Nominations for Board of Governors 1158 Bylaws: Audio Engineering Society, Inc 1159 Index to Volume 47 1163 Cumulative In Memoriam Index . 1171 Education News (insert) DEPARTMENTS Review of Acoustical Patents 1096 Available Literature... 1149 News of the Sections 1141 Membership Information.... 1150 Upcoming Meetings 1146 In Memoriam 1154 Sound Track 1147 AES Conventions and Conferences 1176 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 48 NUMBER 1/2 2000 JANUARY/FEBRUARY

CONTENT PAPERS PEAQ—The ITU Standard for Objective Measurement of Perceived Audio Quality Thilo Thiede, William C.Treurniet, Roland Bitto, Christian Sehmidmer, Thomas Sporer, John G. Beerends, Catherine Colomes, Michael Keyhl, Gerhard Stoll, Karlheinz Brandenburg, and Bernhard Feiten 3 Audio data compression systems rely on algorithms that exploit the psychoacoustic properties of the human auditory system. Subjective evaluations of their overall effectiveness can be expensive as wed as time consuming. This presents the need for an objective measurement method which models the sensory and cognitive processes underlying subjective ratings. This paper describes the ITU-R recommended “ Method for Objective Measurements of Perceived Audio Quality," and its effectiveness in achieving its functional goals. Propagation Distortion in Sound Systems—Can We Avoid It? Eugene Czerwinski, Alexander Voishvillo, Sergei Alexandrov, and Alexander Terekhov 30 The nonlinear properties of sound propagation make it significant to consider the loudspeaker's wave propagation path to the listener as another sound system component that may require nonlinear compensating correction. While, at first examination, this appears to be a simple problem, this study examines the complexity of the acoustical source and its subsequent path configurations, as well as the differences in acoustical path lengths between source and listeners. This is an area of study that is becoming more helpful to the science of sound propagation and reinforcement. ENGINEERING REPORTS A Novel Sound Intensity Probe Comparison with the Pair of Pressure Microphones Intensity Probe W. F. Druyvesteyn and FI. E. de Bree 49 Sound intensity measurements can be made using a novel and simple system called the Microflown, which consists of a microphone and particle velocity sensor. Comparison measurements indicate that this intensity probe system pet forms as well as the older identical -two-microphonc method. The new measurement system offers several advantages over the two-microphone method, which include a reduced size sensor a configuration that can be used over several frequency ranges, and elimination of dose transducer matching as in the identical-two-microphone method. STANDARDS AND INFORMATION DOCUMENTS AES31-3-1999 AES standard for network and file transfer of audio — Audio-file transfer and exchange — Part 3: Simple project interchange 57 DRAFT AES35-xxxx AES standard for audio preservation and restoration — Method for estimating life expectancy of magneto-optic (M-O) disks, based on effects of temperature and relative humidity (insert) DRAFT AES38-xxxx AES standard for audio preservation and restoration — Life expectancy of information stored in recordable compact disc systems — Method for estimating, based on effects of temperature and relative humidity (insert) AES Standards Committee News 91 Status of projects FEATURES The Atlantic Audio Demonstration Equipment A. J. Mason, A. K. McParland, and N. J. Yeadon 106 109th Convention, Los Angeles, Call for Papers 132 109th Convention, Los Angeles, Call for Workshops Participants 134 DEPARTMENTS News of the Sections 119 Advertiser Internet Directory 130 Sound Track 124 Audio Engineering Society Membership New Products and Developments 126 Application Instructions 135 Available Literature 127 Sections Contacts Directory 138 Upcoming Meetings 128 AES Conventions and Conferences 144 Membership Information 129 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 48 NUMBER 3 2000 MARCH

CONTENT

PAPERS Complete Response Function and System Parameters for a Loudspeaker with Passive Radiator Douglas H. Hurlburt 147 The response function for passive radiator loudspeaker systems and closed box types is derived in this study, with the goal to arrive at system designs that include driver losses and internal enclosure and passive radiator losses. A design method that compensates for these losses is fully outlined. This is a comprehensive, step-by-step design development paper, which should serve as a valuable design tool for loudspeaker system engineers.

Evaluation of the ITU-R Objective Audio Quality Measurement Method William C. Treurniet and Gilbert A. Soulodre 164 'The subject of this study was the assessment of the PEAQ ( perceptual evaluation of audio quality ) method's ability to predict and correlate the results of subjective tests conducted according to 1TU -R BS-11 J 6. An additional goal was to determine PEAQ's ability to correctly rank the performance quality of various codecs. The PEAQ system was also evaluated as an aid to selecting appropriate audio listening materials for use in subjective listening tests.

ENGINEERING REPORTS Sculptor: Exploring Timbral Spaces in Real Time N. J. Bailey and D. Cooper 174 Sculptor is a user-adjustable software program which performs analysis and editing of sounds in real time and uses inexpensive hardware. In the system, state-space techniques decompose models of a selected sound into parallel second-order sections whose resonator parameters can then be edited. The modified results can be auditioned in real time. The software's source code is available so that it can be modified to suit individual requirements.

Phantom Sources Applied to Stereo-Base Widening Ronald M. Aarts 181 A stereo-base widening system is described, that is predicated on the combination of head-related transfer functions ( HRTFs ) and a simple idea/ loudspeaker model in conjunction with a subject's acoustically transparent head. It is reported that the spectral response of this widening circuit produces the same tonal balance as conventional stereo reproduction. The system can create extremely wide sound stage broadening effects when used for maneuvering stereo sound effects in action movies.

STANDARDS AND INFORMATION DOCUMENTS AES7-2000 AES standard for the preservation and restoration of audio recording — Method of measuring recorded fluxivity of magnetic sound records at medium wavelengths 190 AES43-2000 AES standard for forensic purposes — Criteria for the authentication of analog audio tape recordings 204 AES Standards Committee News 215 Digital measurements. room diffusion, connectors, control components

FEATURES 32-Bit SIMD SHARC Architecture Digital Audio Signal Processing Applications J. Tomarakos and C. Duggan 220

DEPARTMENTS Review of Acoustical Patents 218 Advertiser Internet Directory 239 News of the Sections 230 Membership Information 240 Upcoming Meetings 234 AES Special Publications 245 Sound Track 235 Sections Contacts Directory 250 New Products and Developments 236 AES Conventions and Conferences 256 Available Literature 239 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 48 NUMBER 4 2000 APRIL

CONTENT

PAPERS Generalized Fractional-Octave Smoothing of Audio and Acoustic Responses Panagiotis D. Hatziantoniou and John N. Mourjopoulos 259 Fractional-octave smoothing methods can be implemented on measured response functions of audio electroacoustic-acoustic systems, which can be complemented by a generalized mathematical framework for smoothing the complex transfer function response. Appropriately modified impulse response functions can also be derived. This additional time-domain information can be useful in many audio engineering applications because it results in functions of reduced complexity while retaining the system’s initial transient and perceptual attributes. Digital Equalizer Coefficient Generation Techniques R. J. Clark, E. C. Ifeachor, G. M. Rogers, and P, W. J. Van Eetvelt 281 Techniques for calculating digital coefficients for discrete-time audio equalizers are examined with dose consideration given to minimizing filter response distortion and the siz.e of the computational load for on-line calculation. Offset and image distortion correction methods are developed to improve the matched z transform ( MZT ) response distortion. Prewarping the peak gain in the MZT distortion results in an affordable computational increase while improving the response, stability, and noise, characteristics of the resulting filters. The effects of the new emerging higher sampling rates and their influence on coefficient transf orms are also explored.

Estimates of Nonlinear Distortion in Feedback Amplifiers Edward M. Cherry 299 Estimates of nonlinear distortion in feedback amplifiers can be characterized by two generators at the input —one voltage and one current. These generators represent the negatives of the voltage and current antidistortion, which, when added to their respective input voltage and current sources, reduce the distortion at the output of the amplifier system to zero. This method predicts harmonic and. intermodulation products for practiced amplifiers and provides design techniques for reducing distortion.

LETTERS TO THE EDITOR Comments on “Subjective Appraisal of Loudspeaker Directivity for Multichannel Reproduction” Tomlinson Holman 314 Author’s Reply Nick Zacharov 317

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News 322 Audio file exchange medium; digital interfaces

FEATURES 108th Convention Report, Paris 326 Exhibitors 344 Program 347 Updates and Corrections to the 1998/1999 International Sections Directory 367 Updates to Review of Society’s Sustaining Members 371 AES News; Historical Committee Projects Move Forward 377

DEPARTMENTS

News of the Sections 372 Membership Information ...., 382 Upcoming Meetings 376 Advertiser Internet Directory 383 Sound Track 378 In Memoriam 385 New Products and Developments 379 Sections Contacts Directory 386 Available Literature 381 AES Conventions and Conferences 392 JOURNAL OFTHE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 48 NUMBERS 2000 MAY

CONTENT PAPERS Objective Modeling of Speech Quality with a Psychoacoustically Validated Auditory Model Martin Hansen and Birger Kolimeier 395 Objective measurement of low-bit rate speech coding algorithms if sing a quantitative psychoacoustical signal processing model has been developed and tested. This model objectively measures the perceptually relevant deviations between the transmitted degraded signal and the corresponding reference signal. A quality measure can be derived from a comparison of these two signals. The performance of this new measurement system was validated by comparing it to alternative models and the PSQM/P 86 I measurement protocol. Design of Three Unusual Loudspeakers for the High Court of Australia Glenn Leembruggen 410 Unique, targeted loudspeaker systems were used to design the High Court of Australia’s sound reinforcement system. Three distinct loudspeaker designs were employed: one is a distributed array of dipole loudspeakers, the second an acoustically curved line array, and the third a short tapered line array. The final peiformance of the loudspeaker system has satisfied both the design goals and the users ’ expectations.

Loudspeakers on Damped Pipes G. L. Augspurger 424 A computer analog to model transmission line loudspeaker systems was developed and validated by comparing it to a variety of designs. Basic peiformance relationships similar to the Thiele-Small analysis of vented boxes are presented. It is also shown that Locanthi’s horn analog is well-suited for modeling transmission line loudspeaker systems using this model. The circuit can accommodate arbitrary flare shapes and allows damping to be included in any combination of series or parallel losses. Using one of the new alignments, a transmission line loudspeaker system can be designed to match the frequency response and efficiency of a comparable closed box, while reducing cone excursion.

ENGINEERING REPORTS A Time-Scale Modification Algorithm Based on the Subband Time-Domain Technique for Broad-Band Signal Applications Roland K. C. Tan and Amerson H. J. Lin 436 Time-domain digital time-scale modification algorithms using the overlap-and-add technique were developed previously mainly for speech signals and may not perform well for broacl-band audio signals. A new algorithm to overcome the problems of the older fonnats has been proposed. The focus in this study has been on the time-scale modification for varying the tempo of audio signals or the rate of speech articulation without altering the pitch of musical instruments or speakers’ or singers' voices.

STANDARDS AND INFORMATION DOCUMENTS AES-6id-2000 AES information document for digital audio — Personal computer audio quality measurements 449 AES Standards Committee News 483 Diffusion; fiber-optic connectors; synchronization; patch panels; grounding ; polarity

FEATURES Audio in the New Millennium James A. Moorer 490 Updates and Corrections to the 1999/2000 International Sections Directory 499 Education News 500

DEPARTMENTS Review of Acoustical Patents 487 Membership Information 512 News of the Sections 502 Advertiser Internet Directory 513 Sound Track 506 AES Special Publications 517 New Products and Developments 508 Sections Contacts Directory 522 Available Literature 510 AES Conventions and Conferences 528 Upcoming Meetings 511 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 48 NUMBER 6 2000 JUNE

CONTENT

PAPERS

Revisiting Algorithms for Predicting the Articulation Loss of Consonants ALcons Sylvio R. Bistafa and John S. Bradley 531 Algorithms proposed for predicting speech intelligibility that are based on articulation loss of consonants ( ALcoll ,) are examined. A simple algorithm, ( he architectural form of the Peutz equation, is discussed and re-derived using a system to further develop empirical equation forms. It is shown that the speech transmission index ( STl ) and the useful -to-detrimental sound ratio (U50 ) speech intelligibility predictions are highly correlated with each other in rooms that have diffuse sound fields exponential decays algorithms, , have a tendency to and ideal . The ALl ( >ns however under-predict speech intelligibility as the signai-to-noise ratio decreases.

ENGINEERING REPORTS

Interactions in a Multiple-Voice-Coil Digital Loudspeaker Yaxiong Huang, Simon C. Busbridge, and Peter A. Fryer 545 Motional impedance and mutual coupling in ci multiple-coil digital loudspeaker system increase the effective impedance of an individual coil relative to its binary weighting in a seven-bit digital

constant -current driver configuration. This places an unreasonably high demand, on the output impedance of the constant -current driver unless the loudspeaker ' s damping is controlled. A shorted turn voice coil can achieve this damping most effectively.

Development of the Wireless “Communications EarPlug” for Application in Military Aviation Sander J. van Wijngaarden, Evert Agterhuis, and Herman J. M. Steeneken 553 Earplugs fitted with integrated miniature speech transducers have been developed specifically for use in high ambient noise level aircraft communications. The earplugs provide isolation from the local noise, while ihe miniature transducers provide a reliable intercommunication path for the user. The system's utility is further enhanced by integrating it with a wireless intercommunications interface, free of any cord connections to the aircraft’s system. Electrically Manifested Distortions of Condenser Microphones in Audio Frequency Circuits Holger Pastille 559 Distortions originate in condenser microphones from several sources: those which are attributable to the microphone’s mechanical and acoustic functions and those which arise from their associated electrical circuitry. An analysis of the electrical design distortion contributions indicate that they are relatively minor in modern condenser microphones which have input resistances on the order of 20 GQ. The distortions of acoustical and mechanical origin contribute more to the overall condenser ' microphone s distortion output than does the electrical circuit’s configuration.

STANDARDS AND INFORMATION DOCUMENTS AES41-2000 AES standard for digital audio — Recoding data set for audio bit-rate reduction 564 AES Standards Committee News 584 Call for comment on revised AES26 audio polarity standard ; digitally intei faced microphones; microphone specifications

FEATURES High-Quality Multichannel Audio Coding: Trends and Challenges Marina Bosi 588

DEPARTMENTS News of the Sections 596 Advertiser Internet Directory 607 Sound Track 600 Audio Engineering Society Membership Upcoming Meetings 601 Application Instructions 610 New Products and Developments 602 AES Special Publications 613 Available Literature 605 Sections Contacts Directory 618 Membership Information 606 AES Conventions and Conferences 624 JOURNAL OFTHE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 48 NUMBER 7/8 2000 JULY/AUGUST CONTENT PAPERS Real-Time Streaming of Multichannel Audio Data over Internet Aoxiang Xu, Wieslaw Woszczyk, Zack Settel, Bruce Pennycook, Robert Rowe, Philip Galanter, Jeffrey Bary, Geoff Martin, Jason Corey, and Jeremy R. Cooperstock 627 An Internet multichannel audio streaming system was demonstrated between McGill University and an audience at New York University. This original system used TCP and UDP protocols with proprieiaty buffering and retransmission algorithms for seamless, uninterrupted performance. Currently neither protocol alone is sufficient for applications of this nature, but ongoing work to combine the advantages of each protocol holds promise for a wide varietyJ offuture applications. Direct Concha Excitation for the Introduction of Individualized Hearing Cues Chong-Jin Tan and Woon-Seng Gan 642 A prototype headphone has been designed to reduce the front -to-back and elevation confusions when used in 3-D sound systems. A proposed acoustical method introduces individual directional auditory cues to excite the concha without the need for individual head- related transfer function ( HRTF ) measurements to correct directional anomalies. It is claimed that this method reduces the directional confusion found in conventional 3- D headphone listening. High-Precision Fourier Analysis of Sounds Using Signal Derivatives Myriam Desainte-Catherine and Sylvain Marchand 654 An original, modified Fourier transform greatly enhances the precision of Fourier analysis in its frequency and amplitude resolution capabilities. This new Fourier analysis is performed in a shorter time frame when compared to more conventional transforms. This method requires the computation of two small, discrete Fourier transforms instead of a single, much larger one. It is of great utility' for extracting spectral modeling parameters in an extremely short time frame. A Theoretical Analysis of Eddy-Current Effects in Loudspeaker Motors J. R. Bowler, N. Harfield, N. P. Merricks, and W. J. Woodman 668 Loudspeaker motor eddy-current effects and their contributions to modified voice-coil impedance and third-order harmonic distortion are discussed in this study. A unique method for reducing the eddy-current-related distortion is presented. The magnetic steel pole tips near the voice coil are replaced with a polymer-based, magnetic powder composite of low conductivity> to eliminate the eddy currents in the voice coil, vicinity*. Theoretical and measured results are in very close agreement. LETTERS TO THE EDITOR Comments on Review of Architectural Acoustics, Principles and Practice David Lloyd ben Yaacov Yehuda Klepper 678 STANDARDS AND INFORMATION DOCUMENTS AES38-2000 AES Standard for Audio Preservation and Restoration — Life Expectancy of Information Stored in Recordable Compact Disc Systems — Method for Estimating, Based on Effects of Temperature and Relative Humidity 679 AES Standards Committee News 706 AES3 J. -3-1999 corrigendum; Los Angeles meetings; IEEE 1394; EMC and grounding ; audio file formats; forensic audio: acoustical levels; listening tests: digital audio measurements FEATURES 109th Convention Preview, Los Angeles 714 Calendar 716 Exhibitors 717 Exhibit Previews 724 110th Convention, Amsterdam, Call for Papers 761 DEPARTMENTS Review of Acoustical Patents 711 Membership Information 758 Upcoming Meetings 750 Advertiser Internet Directory 759 News of the Sections 751 Sections Contacts Directory 762 Sound Track 755 AES Conventions and Conferences .768 Available Literature 756 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 48 NUMBER 9 2000 SEPTEMBER

CONTENT

PAPERS Perceived Performance of Loudspeaker-Spatialized Speech for Teleconferencing Michael J. Evans, Anthony I. Tew, and James A. S. Angus 771 Teleconferencing audio can be enhanced by employing spatial audio reproduction using loudspeakers. It is important that any perceptual realism which is added by spatial audio does not compromise the perceived comprehension of the transmitted teleconferencing communications. Formal testing methods are used to verify that the spatial speech reproduction does not compromise perceived performance relative to nonspatialized reproduction. Loudspeaker Crossovers with Notched Responses Neville Thiele 786 In the continuing development of crossover networks for multidriver loudspeaker systems a class of crossover systems is introduced that produces null responses in the high- and low-pass outputs at frequencies close to their transition crossover frequencies. Both outputs have a high initial rate of attenuation in their stopbands, while the sum of their outputs has a flat all-pass response. Both active and passive designs are introduced with normalized component value examples. ENGINEERING REPORTS Integrated Approach to Metering, Monitoring, and Leveling Practices, Part 1: Two-Channel Metering Bob Kaiz 800 Film, broadcasting , and music recording level-setting practices of the past have led to large variations in the dynamic range of recorded materials. Increased and varying dynamic ranges of modem recording and reproduction systems call for a new set of level-selling requirements. In this paper, the author proposes that recording and reproduction monitor level settings be normalized at 83 dB, and that the available peak levels be adjusted to suit the type of recorded material and reproduction environments, so that the peak dynamic levels exceed the normal reference level by +12 dBfor broadcast materials and by +20 dB for large theater reproduction. Sound Modeling Applied to Flute Sounds SoiviYstad 810 An original method of modeling musical sounds is proposed in which a combination of physical and signal models takes into account the physical characteristics of the instrument along with a technique for extracting parameters for synthesis purposes. A source signal which consists of independent deterministic and stochastic parts is injected into the physical model to generate sustained sounds. Examples are presented of how sounds from this model can be manipulated and how these manipulations can be performed in real time. STANDARDS AND INFORMATION DOCUMENTS AES35- 2000 AES standard for audio preservation and restoration — Method for estimating life expectancy of magneto-optic (M-O) disks, based on effects of temperature and relative humidity 826 AES Standards Committee News 846 Status of projects

FEATURES Global Paradigm Shifts in the Audio Industry—Part 1 Barry Blesser and Derek Pilkington 861 110th Convention, Amsterdam, Call for Papers 887 AES 19th International Conference, Bavaria, Germany, Call for Contributions 888 DEPARTMENTS News of the Sections 873 Advertiser Internet Directory 886 Sound Track 878 Audio Engineering Society Membership Upcoming Meetings 880 Application Instructions 890 New Products and Developments, 880 AES Special Publications 893 Available Literature 882 Sections Contacts Directory 898 Membership Information 884 AES Conventions and Conferences 904 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 48 NUMBER 10 2000 OCTOBER CONTENT President’s Message Roy Pritts 907 PAPERS Directional Loudspeakers Using Sound Beams David I. Havelock and Anthony J. Brammer 908 Several control formats that limit loudspeaker radiation to a defined area are described. The study is supported by extensive data to illustrate the effectiveness of various designs. The authors have concentrated on systems that use a single transducer in conjunction with various acoustic duct configurationsfor acoustic radiation beam control. A Dual-Band Equalizer for Loudspeakers Peng Wang, Wee Ser, and Ming Zhang 917 Manx of the digital equalizersfor loudspeaker systems are unable to effectively equalize low - frequency components. A new method is proposed which incorporates a warpedfilter into the conventional equalizer design. Computer simulation results indicate that the proposed method can improve the performance of the equalized response at lowfrequencies, and can be extended to suit the requirements of different types of loudspeakers. ENGINEERING REPORTS A Revised Low-Frequency Horn of Small Dimensions Roy Delgado, Jr., and Paul W. Klipsch 922 A widely used commercial loudspeaker system, originally described in 1941, has been modified and improved. The modern version of this system claims smoother response in the passband region, reduced, distortion, and an increase in its upperfrequency limit. These and other improvements have been installed in a cabinet which occupies the samefootprint as that of the original design. Computation and Memory Tradeoffs in Wavetable-Filter Matching of Musical Instrument Tones Alan Ng and Andrew Horner 930 The authors have investigated the computation and memory tradeoffs in matching harmonic instrument tones with a hybrid wavetablc filter synthesis model. The study examines the best combination of wavetabiesfollowed by a time-varyingfilterfor computation and storage efficiency. It is shown that devoting all of the computation and memory to the wavetabies results in the best overall performance tradeoff. LETTERS TO THE EDITOR Addendum to “Generalized Fractional-Octave Smoothing of Audio and Acoustic Responses” Panagiotis D. Hatziantoniou and John N. Mourjopoulos 940 Comments on “A Time-Scale Modification Algorithm Based on the Subband Time-Domain Technique for Broad-Band Signal Applications” Roland K. C. Tan and Amerson H. J. Lin 940 STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News 941 optical media; magnetic media; mechanical media Call for Comment on REAFFIRMATION of AES-10id-1995, AES information document for digital audio engineering — Engineering guidelines for the multichannel-audio digital interface (MADI) AES10 941 Call for Comment on DRAFT AES42-xxxx, DRAFT AES standard for acoustics — Digital interface for microphones 941 Call for Comment on DRAFT AES-4id-xxxx, DRAFT AES information document for room acoustics and sound reinforcement systems — Characterization and measurement of surface scattering uniformity 941 FEATURES Global Paradigm Shifts in the Audio Industry, Part 2 Barry Blesserand Derek Pilkington 946 AES Officers 200072001 960 Review of Society’s Sustaining Members 962 Updates and Corrections to the 1999/2000 International Sections Directory ... 980 AES 19th International Conference, Bavaria,Germany, Call for Contributions 996 AES 20th International Conference, Budapest, Hungary, Call for Papers 998 DEPARTMENTS Review of Acoustical Patents 944 Membership Information 991 Upcoming Meetings 981 Advertiser Internet Directory 995 News of the Sections 982 Audio Engineering Society Membership Sound Track 987 Application Instructions 999 New Products and Developments 988 Sections Contacts Directory 1002 Available Literature 989 AES Conventions and Conferences 1008 JOURNAL OFTHE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 48 NUMBER 11 2000 NOVEMBER CONTENT PAPERS Frequency-Warped Signal Processing for Audio Applications Aki Harma, Matti Karjalainen, Lauri Savioja, Vesa Valimaki, Unto K. Laine, and Jyri Huopaniemi 1011 A digital signal processing method is presented, which is applicable to human auditory perception. It. is an effective means to design or implement digital signal processing ( DSP ) algorithms directly. The human auditory system is complex, nonlinear, lime variant, and adaptive. Therefore, models of auditory perception are also complex. This paper demonstrates that a warped DSP system can be designed to approximate accurately the frequency resolution of the human auditory system. Auditory Models for Gifted Listeners Seymour Shlien 1032 Little is known about gifted listeners, some of whom are remarkably sensitive to codec quantization noise. Training appears to be an important aspect in. the development of these abilities. This study indicates that sensitivity to codec quantization noise is likely governed by psychoacoustic efficiency rather than unique frequency selectivi( y.

ENGINEERING REPORTS Recurrent Neural-Network-Based Physical Model for the Chin and Other Plucked-String Instruments Sheng-Fu Liang and Alvin W. Y. Su 1045 A traditional Chinese plucked-string instrument, the chin, is chosen to demonstrate the use of neural networks to determine suitable synthesis parameters. The structure of the network is designed for analysis of plucked-string instruments and its corresponding synthesis engine. This is a general method that can be used to synthesize any plucked-string musical instrument.

COMMUNICATIONS Aliasing in Digital Clippers and Compressors Paul Kraght 1060 Digital signal limiters and dynamic-range compressors generate aliasing products as an undesirable side effect that can be clearly audible. Reduced aliasing can be achieved by soft limiting, at the expense of reduced overall dynamic range. A second or higher order detector can be used to effectively eliminate aliasing in digital signal processing systems.

LETTERS TO THE EDITOR More on "Comments on Review of Architectural Acoustics, Principles and Practice" David Lloyd ben Yaacov Yehuda Klepper 1066 Comments on "Complete Response Function and System Parameters for a Loudspeaker with Passive Radiator" Josef Merhaut 1066 Author’s Reply Douglas FI. Hurlburt 1067

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News 1068 Corrigenda; metadata; diffusion materials; loudspeakers; tape preservation; digital interfaces; internet audio Call for Comment on REAFFIRMATION of AES-2id-1996, AES information document for digital audio engineering — Guidelines for the use of the AES3 interface 1068

FEATURES 109th Convention Report, Los Angeles 1074 Exhibitors 1090 Program 1094 10th Tokyo Regional Convention, Call for Papers 1138 111th Convention, New York,Call for Papers 1139 AES 20th International Conference, Budapest, Hungary, Call for Papers 1140

DEPARTMENTS News of the Sections 1121 Advertiser Internet Directory 1134 Sound Track 1126 In Memoriam 1136 Upcoming Meetings 1128 AES Annual Report 1137 New Products and Developments 1128 AES Special Publications 1141 Available Literature 1130 Sections Contacts Directory 1146 Membership Information 1131 AES Conventions and Conferences 1152 JOURNAL OFTHE AUDIO ENGINEERING SOCIETY AESAUDIO/ACOUSTICS/APPLICATIONS VOLUME 48 NUMBER 12 2000 DECEMBER

CONTENT

PAPERS A Unified Theory of Horizontal Holographic Sound Systems M. A. Poletti 1155 A theoretical basis for a horizontal holographic surround sound system, using the two-dimensional Fourier transform, is presented in depth. It is shown how the theory leads to the recording and reproduction of sound fields using circular arrays of microphones and loudspeakers. The reproduction of a five-loudspeaker surround system is also examined, and its performance over wider reproduction areas is considered. DSP Equalization of Electret Film Pickup for the Acoustic Guitar Matti Karjalainen, Vesa Valimaki, Henri Penttinen, and Harri Saastamoinen 1183 The sound quality of a guitar's bridge electret film pickup does not match that of the instrument's acoustic sound. To enhance the instrument’s pickup sound and to simulate its acoustic attributes, the authors have applied digital signal processing to recreate its acoustic sound characteristics. If the equalizer uses a programmable digital signal processor, additional features such as various sound effects or a reverberation function can be added easily.

An Air-Cored Autotransformer with Nearly Equal Taps A. N. Thiele 1194 An autotransformer as the first shunt inductor at the input of a high- pass filter serving as a crossover element in a loudspeaker system permits the level adjustment of individual drivers without changing the frequency or phase response. This arrangement eliminates interaction with other drivers in the system array when the individual levels are adjusted to equalize the differences in driver sensitivities. There are numerous circuit examples given which can assist in implementing this concept.

ENGINEERING REPORTS Loudspeaker Response Improvement Using ConeThickness Variation David Featherston and Michaii Barabasz 1216 The effect a variation in a loudspeaker’s cone body thickness has on a felted paper cone has been studied. A modified cone thickness profile with changes at a given radius showed improved high- frequency response in this study. It was further shown that thickness modifications can be used to reduce diaphragm mass and lead to improved overall loudspeaker efficiency.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News 1221 Working group reorganization; digital measurement; file exchange; system control; microphones; acoustic files; fluster; synchronization

FEATURES

DVD-Audio Specifications Norihiko Fuchigami, Toshio Kuroiwa, and Bike H. Suzuki 1228 2000/2001 AES International Sections Directory 1241 Education News 1263 Call for Nominations for Board of Governors 1271 Call for Nominations for Awards 1272 10th Tokyo Regional Convention, Call for Papers 1280 111th Convention, New York, Call for Papers 1281 Bylaws: Audio Engineering Society, Inc 1282 Index to Volume 48 1286

DEPARTMENTS

News of the Sections 1264 Membership Information 1273 Upcoming Meetings 1265 Advertiser Internet Directory 1277 Sound Track 1266 In Memoriam ....1278 New Products and Developments 1268 AES Conventions and Conferences ....1296 Available Literature 1270 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 49 NUMBER 12 2001 DECEMBER CONTENT PAPERS High-Intensity Infrasonic Acoustic Test System that Uses a Two-Volume Helmholtz Resonator ...... H. Edwin Boesch, Jr., Christian G. Reiff, and Bruce T. Benwel 1131 Generation of clean high-amplitude subsonic test audio in the region of 2 to 20 Hz requires a completely different approach that uses compressed air and mechanical modulators rather than conventional drivers. Large-scale Helmholtz resonators then create a clear signal. The test environment explores the biological effects of such signals on humans. Classical acoustic models predict the observed behavior. Comparison of Numerical Simulation Models and Measured Low-Frequency Behavior of Loudspeaker Enclosures ....Matti Karjalainen,Veijo Ikonen, Poju Antsalo, Panu Maijala, Lauri Savioja, Antti Suutala, Seppo Pohjolainen 1148 Powerful computer processing and sophisticated software tools are now adequate to apply element-based vibroacoustic simulation to the modeling of loudspeaker enclosures. Boundary-element, finite-element, and finite-difference time-domain methods are explored in the design of an enclosure. A comparison of the measured and predicted results shows good agreement in almost all cases, but especially at low frequencies. The quality of the results is limited only by the accuracy of the physical parameters. A Method for Long Extrapolation of Audio Signals ...... Ismo Kauppinen, Jyrki Kauppinen, and Pekka Saarinen 1167 The use of extrapolation to replace relatively long segments of audio that have been corrupted or destroyed is demonstrated with an impulse-response model derived from the audio before and after the segment. Three methods for deriving the prediction parameters are explored using real music in order to synthesize thousands of missing samples. In most cases, listeners could not identify the sample with the extrapolated audio segments. Multitone Testing of Sound System Components—Some Results and Conclusions, Part 2: Modeling and Application ...... Eugene Czerwinski, Alexander Voishvillo, Sergei Alexandrov, and Alexander Terekhov 1181 A new nonlinear distortion technique, described in Part 1 of this paper published in the 2001 November issue, is applied to a pair of horn drivers each having a similar harmonic distortion value. The difference in the intermodulation products between the target and reference drivers correlates with the subjective perception. The validation of the new approach originates from the more complete nonlinear signature of the created tones. However, interpretation of that pattern in terms of the physical properties is both difficult and rewarding. The failure of harmonic distortion measurement is clearly demonstrated. STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News ...... 1193 Microphone characteristics; file exchange; listening tests

FEATURES 111th Convention Report, New York ...... 1196 Exhibitors...... 1210 Program ...... 1213 New Officers 2001/2002...... 1237 2001/2002 AES International Sections Directory ...... 1242 Call for Nominations for Board of Governors...... 1275 Call for Awards Nominations...... 1276 113th Convention, Los Angeles, Call for Papers ...... 1283 Bylaws: Audio Engineering Society, Inc...... 1284 Index to Volume 49 ...... 1288

DEPARTMENTS News of the Sections ...... 1266 Available Literature ...... 1273 Sound Track ...... 1270 Membership Information...... 1277 New Products and Developments ...... 1271 Advertiser Internet Directory...... 1278 Upcoming Meetings ...... 1273 AES Conventions and Conferences ...... 1296 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 50 NUMBER 1/2 2002 JANUARY/FEBRUARY CONTENT President’s Message...... Garry Margolis 3 PAPERS Fourth-Order Symmetrical Band-Pass Loudspeaker Systems ...... Grzegorz P.Matusiak and Andrzej B. Dobrucki 4 The analysis of fourth-order band-pass loudspeaker systems based on the well-known Thiele, Small, and Benson theory is presented using a reactance transformation method. By comparing the acoustic analog circuit with the transfer function obtained from the reactance transformation, the results allow the symmetry condition to be determined. The resulting system has advantages over closed-box and vented-box high-pass systems in terms of power and efficiency. Maximizing Performance from Loudspeaker Ports ...... Alex Salvatti, Allan Devantier, and Doug J. Button 19 The low-frequency performance of a loudspeaker is significantly enhanced by the use of tapered ports, but there are numerous trade-offs involving the size of the port and the input and output tapers. Design issues include the effectiveness of heat transfer, amount of turbulence created, air velocity, smoothness of the taper, symmetry of the two tapers, effective mass in the port, and the contribution to the frequency response. Suggested design rules are based on extensive empirical studies. ENGINEERING REPORTS Wavetable Matching of Inharmonic String Tones ...... Clifford So and Andrew B. Horner 46 A new wavetable matching technique for inharmonic music tones, such as a violin with vibrato, shows good spectral matching and adequate frequency resolution. Confirmation with listening tests significantly improves the perceived matching but degrades performance on harmonic trumpet tones compared to simple wavetable matching. The new method offers more than a three-fold improvement over additive synthesis for these cases, but for harmonic tones the original matching technique should be used. Localization of Virtual Sound as a Function of Head-Related Impulse Response Duration ...... Melis A. Senova, Ken I. McAnally, and Russell L. Martin 57 The localization accuracy of subjects using headphones was determined as a function of the duration of the head-related impulse response. Unlike previous studies, there was a gradual decrease in accuracy starting at 10 ms and becoming drastically worse at about 0.5 ms. Durations of more than 10 ms result in performance indistinguishable from free-field localization. Shorter durations are equivalent to smoothing the frequency response and thereby removing the fine detail unique to each subject’s own ears. CORRECTIONS Correction to “Multitone Testing of Sound System Components—Some Results and Conclusions, Part 1: History and Theory” ...... Eugene Czerwinski, Alexander Voishvillo, Sergei Alexandrov, and Alexander Terekhov 66 STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 67 ATM networking; acoustics measurement; EMC; IEEE1394 networks; network and file transfer Call for Comment on DRAFT AES47-xxxx, DRAFT AES standard on digital audio digital input-output interfacing transmission of digital audio over asynchronous transfer mode (ATM) networks...... 67 Call for Comment on REAFFIRMATION of AES18-1996, AES recommended practice for digital audio engineering — Format for the user data channel of the AES digital audio interface...... 67 Call for Comment on REAFFIRMATION of AES20-1996, AES recommended practice for professional audio — Subjective evaluation of loudspeakers...... 68 Call for Comment on REAFFIRMATION of AES27-1996, AES recommended practice for forensic purposes — Managing recorded audio materials intended for examination...... 68 Call for Comment on WITHDRAWAL of AES15-1991, AES recommended practice for sound- reinforcement systems — Communications interface (PA-422) ...... 68 FEATURES Audible Alarms for the Hearing Impaired ...... John Vanderkooy 73 Education News...... 81 113th Convention, Los Angeles, Call for Papers ...... 100 DEPARTMENTS News of the Sections ...... 82 Advertiser Internet Directory...... 97 Upcoming Meetings ...... 87 In Memoriam ...... 98 Sound Track...... 88 AES Special Publications ...... 101 New Products and Developments...... 90 Sections Contacts Directory ...... 106 Available Literature ...... 92 AES Conventions and Conferences ...... 112 Membership Information...... 93 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 50 NUMBER 3 2002 MARCH

CONTENT

PAPERS Effect Design, Part 3 Oscillators: Sinusoidal and Pseudonoise...... Jon Dattorro 115 This is the third of a three-part series that provides a tutorial reference for those signal processing algorithms that are of particular interest to music. In this part, the issues of low-frequency sinusoidal oscillators and sonically pleasant pseudorandom noise generators are reviewed, compared, and analyzed. Both topics actually have deep issues even though the signal definitions are simple. The historical background, pertinent references, and appendices provide the reader with a comprehensive foundation in these subjects. Reproducing Low-Pitched Signals through Small Loudspeakers ...... Erik Larsen and Ronald M. Aarts 147 Because small-volume loudspeakers are unable to reproduce low frequencies, alternative methods can be used to create the illusion of those frequencies by taking advantage of a phantom-pitch phenomenon—the perception of a fundamental when only its harmonics are present. The low frequencies below the loudspeaker cutoff point are extracted from the wide-band signal, nonlinearly processed, filtered again, and finally injected into the path of the main signals. Listeners prefer this artificial bass in comparison to flat reproduction through a small loudspeaker. A particular implementation of phantom pitch is illustrated. Generating Source Streams for Extralinguistic Utterances...... Eduardo Reck Miranda 165 Most speech-synthesis systems do not provide a mechanism for creating nonspeechlike signals, such as sounds like boom, meow, gurgles, and genetic vocal noises. To avoid the mechanical-sounding attributes of other approaches, the author adapts a cellular automata control of the spectral parameters. The array of parameters is updated according to a set of rules to create transitions between states using the values of the neighboring cells as input parameters. While this approach works well to create natural sounds, there is insufficient knowledge about how to create an imagined sound.

ENGINEERING REPORTS Estimating the Loudspeaker Response when the Vent Output is Delayed...... Neville Thiele 173 A new wavetable-matching technique for inharmonic music tones, such as a violin with vibrato, shows good spectral matching and adequate frequency resolution. Confirmation with listening tests significantly improves the perceived matching but degrades performance on harmonic trumpet tones compared to simple wavetable matching. The new method offers more than a three-fold improvement over additive synthesis for these cases, but for harmonic tones the original matching technique should be used.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 176 Audio connectors

FEATURES 112th Convention Preview, Munich...... 178 Calendar...... 180 Exhibitors...... 181 Exhibitor Previews ...... 184 113th Convention, Los Angeles, Call for Workshops Participants ...... 206

DEPARTMENTS News of the Sections ...... 201 In Memoriam ...... 212 Upcoming Meetings ...... 203 AES Special Publications ...... 213 Sound Track...... 205 Sections Contacts Directory ...... 218 Membership Information...... 207 AES Conventions and Conferences ...... 224 Advertiser Internet Directory...... 209 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 50 NUMBER 4 2002 APRIL

CONTENT

PAPERS Restoration and Enhancement of Solo Guitar Recordings Based on Sound Source Modeling ...... Paulo A. A. Esquef, Vesa Välimäki, and Matti Karjalainen 227 By combining techniques for music synthesis and analysis, the authors demonstrated that the restoration of guitar recordings had been corrupted by added noise and limited spectral bandwidth. During the analysis phase the parameters of the synthesis model were extracted and then used to define the synthesis model, which is able to produce a simulation without noise or spectral limits. The initial corruption and the musical complexity limit the accuracy of the parameter extraction. The results of this work should be considered a pilot study. On the Quality of Hearing One’s Own Voice ...... Ronald Appel and John G. Beerends 237 Evaluating the quality of sound reproduction in a telecommunications environment over long distances is unique and unrelated to the classical problem of reproduction quality. Specifically, the experiments attempt to calibrate the acceptable quality level for the listener’s own voice through the side channel when it has been delayed and distorted. The proposed model represents degradation as a single number to predict the subjective experience of comfort while talking and listening to one’s own voice. Comparison of Different Impulse Response Measurement Techniques ...... Guy-Bart Stan, Jean-Jacques Embrechts, and Dominique Archambeau 249 Although the impulse response of a linear, time-invariant system is mathematically defined, the choice of empirical methods strongly influences the results when applied to a real room with noise and other imperfections. The authors explored the relationship between the environment under test and four different approaches: maximum-length sequences, inverse repeated sequences, time-stretched pulses, and SineSweep. Recommended choices are suggested based on noise level, accuracy, and calibration effort.

ENGINEERING REPORTS Variability in the Headphone-to-Ear-Canal Transfer Function ...... Ken I. McAnally and Russell L. Martin 263 The quality of virtual auditory space simulation using headphones is determined, in part, by the accuracy of the head-related transfer function that models the influence of the head and pinna as a function of sound location. A potential problem with the resulting filters is that the transfer function is influenced by the variability of listener headphone placement, which might change the localization accuracy. After careful study the authors concluded that the variability is not sufficient to significantly influence perception.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 267 Call for comment communications; digital interfacing; preservation and restoration

FEATURES 21st Conference Preview, St. Petersburg, Russia...... 274 Calendar...... 276 Program...... 278 Registration Form ...... 289 22nd Conference Preview, Espoo, Finland...... 290 Calendar...... 292 Program...... 293 Registration Form ...... 301 Updates and Corrections to the 2001/2002 International Sections Directory...... 302

DEPARTMENTS Review of Acoustical Patents...... 271 Membership Information...... 311 News of the Sections ...... 303 Advertiser Internet Directory...... 312 Sound Track...... 307 AES Special Publications ...... 315 New Products and Developments...... 308 In Memoriam ...... 320 Upcoming Meetings ...... 310 Sections Contacts Directory ...... 322 Available Literature ...... 310 AES Conventions and Conferences ...... 328 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 50 NUMBER 5 2002 MAY CONTENT PAPERS A Model of Loudness Applicable to Time-Varying Sounds ...... Brian R. Glasberg and Brian C. J. Moore 331 A previous model for computing the subjective loudness of steady-state sounds from their spectra has been extended to include time variations. After filtering the input signal to mimic the frequency response of the outer and middle ear, a fast Fourier transform (FFT) of the resulting signal is then used to compute an instantaneous loudness. The overall loudness uses attack and release times to convert the instantaneous loudness to the subjective experience of the listeners. The model gives good results with modulated signals over a wide range of rates. Perception of Reverberation Time in Small Listening Rooms...... T.I. Niaounakis and W. J. Davies 343 Spatial parameters, such as reverberation time, are typically used for large spaces and have not been extensively applied in a small room. This study determined that listeners’ sensitivity to changes in reverberation time was on the order of 40 ms. Two methods were used: changing absorption in a real space and simulating changes from a dummy head with delay headphone reproduction.

ENGINEERING REPORTS An IIR Synthesis Method for Plucked-String Instruments with Embedded Portamento ...... Alvin W.Y. Su, Wei-Chen Chang, and Rei-Wen Wang 351 The normal wavetable technique for synthesizing the portamento of plucked-string instruments, such as the ancient Chinese San-Sien, fails because of the wide frequency range. A new approach, which uses a wavetable to drive an infinite-impulse-response (IIR) filter whose coefficients have been modeled as a neural network training algorithm, provides accurate synthesis of these unusual sounds. The method assumes that the sounds are quasi-periodic, which also makes the method appropriate for certain wind instruments. Signal processing requirements are not particularly problematic. Dipole Loudspeaker Response in Listening Rooms ...... James M. Kates 363 A dipole loudspeaker, which radiates sound energy from both the front and rear surfaces, appears as a velocity source, whereas the conventional monopole loudspeaker appears as a pressure source. Although the dipole loudspeaker can provide better auditory localization accuracy, it is more sensitive to room placement and angular orientation. Using a two-dimensional simulation, the author explores the importance of room response and coloration of the reproduced sounds.

LETTERS TO THE EDITOR Comments on In Memoriam...... Roy Allison 375

CORRECTIONS Correction to Content Page ...... 375

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 376 Digital audio measurements; loudspeaker modeling; audio connections

FEATURES Managing Change: The Challenge of Rights Management in the New Millennium ...... Keith Hill 380 Audio for Games...... Martin Wilde 392 114th Convention, Amsterdam, Call for Papers ...... 417

DEPARTMENTS News of the Sections ...... 397 Advertiser Internet Directory...... 410 Upcoming Meetings ...... 401 AES Special Publications ...... 411 Sound Track...... 402 In Memoriam ...... 416 New Products and Developments...... 404 Sections Contacts Directory ...... 418 Available Literature ...... 407 AES Conventions and Conferences ...... 424 Membership Information...... 408 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 50 NUMBER 6 2002 JUNE

CONTENT

PAPERS Magnetic Circuit Design Methodologies for Dual-Coil Transducers...... Douglas J. Button 427 Renewed interest in the old idea of using dual voice coils, axial not concentric, leads to reconsidering this architectural approach to modern consumer and professional applications. The author reviews and analyzes numerous design tradeoffs in magnetic materials, magnetic geometries, and voice-coil topologies in order to illustrate potential advantages of this approach to driver design. Advantages, when compared to single-coil drivers, include weight, power handling, power compression, and distortion. An additional shorted coil between the two drive coils acts as dynamic braking. Loudspeaker Voice-Coil Inductance Losses: Circuit Models, Parameter Estimation, and Effect on Frequency Response ...... W. Marshall Leach, Jr. 442 Modeling of the losses in a loudspeaker voice coil is not straightforward, even when the series resistance is separated from the inductor and when both are viewed as discrete elements. The parametric representation of the inductor must include a frequency-dependent resistance and inductance in parallel. A SPICE analysis is compared to experimental data in order to validate the proposed parameters that incorporate the frequency-dependent impedance and phase. Similarity Evaluation of Room Acoustic Impulse Responses: Visual and Auditory Impressions ..Akira Omoto, Chizuko Hiratsuka, Hiroaki Fujita, Tetsuhiko Fukushima, Masataka Nakahara, and Kyoji Fujiwara 451 A comparison between the original impulse response of a room and its simulation must be made in order to evaluate the quality of the simulation. However, this leads to the dilemma of using a listening or visual method for judging similarity. In this study a single frequency band was deliberately changed in amplitude to create a controlled difference between the two cases, which then served as a basis for evaluating the two methods of judgment. Results show a very high level of correlation between visual inspection and subjective listening. A New Nonstationary Test Procedure for Improved Loudspeaker Fault Detection ...... Manuel Davy and Christian Doncarli 458 Manufacturing efficiencies require a general method to automatically detect production faults without any prior information about the nature of such faults. The authors propose a method that uses a mixture of four chirped signals covering the complete frequency range as a brief signal that mimics a speech or musiclike stimulus. The method was evaluated by comparing aged loudspeakers with varying levels of fatigue with new loudspeakers. The approach does not require a special environment or a model of the loudspeaker or its failure modes. Yet the results are accurate.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 470 Radio traffic data; preservation and restoration; analog recording; transfer technologies

FEATURES 112th Convention Report, Munich...... 474 Exhibitors...... 492 Program...... 495 Updates and Corrections to Review of Society’s Sustaining Members ...... 526 114th Convention, Amsterdam, Call for Papers ...... 535

DEPARTMENTS Review of Acoustical Patents...... 472 Available Literature ...... 534 Upcoming Meetings ...... 526 Membership Information...... 536 News of the Sections ...... 527 In Memoriam ...... 537 Sound Track...... 531 Sections Contacts Directory ...... 538 New Products and Developments...... 532 AES Conventions and Conferences ...... 544 Advertiser Internet Directory...... 534 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 50 NUMBER 7/8 2002 JULY/AUGUST

CONTENT

PAPERS On the Design and Efficiency of Class A, B, AB, G, and H Audio Power Amplifier Output Stages ...... Rosalfonso Bortoni, Sidnei Noceti Filho, and Rui Seara 547 Audio power amplifiers are usually analyzed with resistive loads with an added compensation factor for nominally reactive loads of real loudspeakers. The current study examines amplifiers of class A, B, AB, G, and H under conditions of reactive loads with sine wave to determine the true stress on the power stage. By using a more exact method, the economic inefficiency of the older approximation is avoided. A procedure for designing and assessing output stages is also proposed. Requirements for Low-Frequency Sound Reproduction, Part I:The Audibility of Changes in Passband Amplitude Ripple and Lower System Cutoff Frequency and Slope...... S¿ren Bech 564 The low-frequency loudspeaker in a 5.1 system has been investigated in terms of perception of its frequency cutoff, slope of the cutoff, and passband ripple. The cutoff frequency has a very significant effect on the subjective sense of “lower bass,” but the cutoff slope was found not to be significant. The audibility of ripple depends on the nature of the audio signal. Results were consistent in both an anechoic test procedure and a headphone simulation of that environment.

ENGINEERING REPORTS Requirements for Low-Frequency Sound Reproduction, Part II: Generation of Stimuli and Listening System Equalization...... Jan Abildgaard Pedersen and Aki Mäkivirta 581 Using headphones to simulate the perception of loudspeakers in an anechoic chamber is easier and more efficient, but it requires signal processing to produce the equivalent sound signals. This study describes the algorithms used in a previous study of the low-frequency channel loudspeaker. Signals were pre-equalized with added nonlinear processing based on head-related transfer measurements made in an anechoic chamber with an actual loudspeaker. Reconstruction Method for Missing or Damaged Long Portions in Audio Signal ...... Ismo Kauppinen and Jyrki Kauppinen 594 Using a reconstruction method described previously, the authors demonstrate an algorithm that replaces gaps of up to several thousand samples with synthesized audio. Using three different types of music, the extrapolation method was able to reconstruct successfully the missing audio, so that listeners could not hear the difference between it and the original. The method was applied in practice to correct scratches from badly damaged recordings, but it can also work with any kind of impulse noise in real time.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 603 Acoustics and sound-source modeling Call for Comment on REVISION of AES10-1991(r1997), AES recommended practice for digital audio engineering—Format for the user data channel of the AES digital audio interface...... 603

FEATURES 113th Convention Preview, Los Angeles ...... 606 Calendar...... 608 Exhibitors...... 610 Exhibit Previews...... 614 Updates and Corrections to the 2001/2002 International Sections Directory...... 636 23rd Conference, Copenhagen, Call for Papers...... 641

DEPARTMENTS News of the Sections ...... 629 Membership Information...... 637 Upcoming Meetings ...... 634 In Memoriam ...... 639 Sound Track...... 635 Sections Contacts Directory ...... 642 Advertiser Internet Directory...... 635 AES Conventions and Conferences ...... 648 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 50 NUMBER 9 2002 SEPTEMBER

CONTENT

PAPERS Spatial Quality Evaluation for Reproduced Sound: Terminology, Meaning, and a Scene-Based Paradigm...... Francis Rumsey 651 Improving the quality of spatial reproduction suffers because of an incomplete definition of the subjective attributes that contribute to the experience of space. Moreover, the lexicon of spatial concepts is often ambiguous and ill defined. This review of existing standards and research highlights the problem of extending controlled laboratory results to real applications of sound reproduction, especially when different goals, such as evaluating equipment versus modeling human perception, are involved. Describing Telephone Speech Codec Quality Degradations by Means of Impairment Factors ...... Sebastian Möller and Jens Berger 667 Predicting the quality of a telephone channel with multiple sources of degradations from a variety of codecs is a labor-intensive activity that must be repeated for each condition. The authors propose a perceptually based model that produces a single equipment impairment index as a way to approximate the degradation contributed by a particular device. Preliminary results suggest that the proposed algorithm, based on auditory tests, provides insight into the expected results. Low-Crest-Factor Multitone Test Signals for Audio Testing ...... Alexander Potchinkov 681 Test signals composed of a large number of discrete frequencies offer the advantage of high-speed measurements and the ability to simulate the spectrum of natural audio under controlled conditions. However, selecting the phase relationship to minimize the crest factor becomes a special problem. Minimizing the crest factor increases the signal power for a fixed clipping level. This paper shows that ad hoc schemes are useful but often inferior to a formal optimization, and that they should not be used if enough compute time is available for a theoretical optimization.

ENGINEERING REPORTS About the 10-dB Switch of a Condenser Microphone in Audio Frequency Circuits ...... Holger Pastillé and Martin Ochmann 695 Because high sound levels can overload the input preamplifier of a condenser microphone, one of two techniques is typically used to reduce the level: switching a parallel capacitor across the microphone or reducing the polarizing voltage. Both techniques reduce the signal level but with very different effects on nonlinearity. This paper explores both the mathematical and practical implications of level reduction, with a warning to users faced with an overload condition.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 703 Internet communications update; synchronization; forensic audio; microphone measurement; listening tests; audio connections Survey: Fiber Optic Connectors ...... insert

FEATURES 21st Conference Report, St. Petersburg ...... 710 23rd Conference, Copenhagen, Call for Papers...... 737 24th Conference, Banff, Call for Contributions...... 738

DEPARTMENTS Review of Acoustical Patents...... 708 Membership Information...... 732 News of the Sections ...... 718 Advertiser Internet Directory...... 734 Sound Track...... 725 In Memoriam ...... 736 Upcoming Meetings ...... 726 AES Special Publications ...... 741 New Products and Developments...... 727 Sections Contacts Directory ...... 746 Available Literature ...... 731 AES Conventions and Conferences ...... 752 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 50 NUMBER 10 2002 OCTOBER

CONTENT

PAPERS Perceptual Evaluation of Speech Quality (PESQ): The New ITU Standard for End-to-End Speech Quality Assessment Part I—Time-Delay Compensation...... Antony W. Rix, Michael P.Hollier, Andries P.Hekstra, and John G. Beerends 755 Creating a model for the subjective speech quality in modern telephone networks, which includes voice- over Internet, presents special problems because of time-varying delay during transmission. Including delay compensation in the evaluation algorithm is required in order to match subjective judgments. The paper explores the numerous origins of variable delay and its perceptual influence on subjective quality. Delay can only be considered to be constant over relatively short intervals. Perceptual Evaluation of Speech Quality (PESQ):The New ITU Standard for End-to-End Speech Quality Assessment Part II—Psychoacoustic Model...... John G. Beerends, Andries P.Hekstra, Antony W. Rix, and Michael P.Hollier 765 Using delay compensation, as described in Part I above, the authors present a full psychoacoustic model for the perceptual evaluation of speech quality in telephone systems to predict the end-to-end judgment of subjective degradation. The final quality score is a combination of many independent measures. Although extensive empirical testing of the cognitive model showed that it provided a much better measure of degradation than previous approaches, additional factors are yet to be included in the model. Improved Microphone Array Configurations for Auralization of Sound Fields by Wave-Field Synthesis...... Edo Hulsebos, Diemer de Vries, and Emmanuelle Bourdillat 779 In order to provide accurate auralization when reproducing an acoustic field in a large space, significant amounts of impulse response data are required. The paper investigates and compares three classes of microphone array configurations: linear, cross, and circular. The proposed circular configuration, the basis for wave-field synthesis, provides better spatial reconstruction over a wider area because it avoids diffraction effects present at the end points in the other configurations. Crossover Systems in Digital Loudspeakers ...... S. C. Busbridge, Y.Huang, and P.A. Fryer 791 Implementing a crossover network for a digital loudspeaker allows the individual binary currents to be filtered into two spectral channels because the operations of digital-to-analog conversion and filtering can be interchanged. The paper explores a mathematical simulation of a proposed digital loudspeaker using a separate voice coil for each bit. Actual measurements from an experimental system are then used to support the results.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 799 Digital interfacing; digital libraries; loudspeaker modeling and measurement; high-performance serial bus

FEATURES 22nd Conference Report, Espoo ...... 804 New Officers 2002/2003...... 814 Review of Society’s Sustaining Members ...... 816 Education News...... 838 24th Conference, Banff, Call for Contributions...... 851

DEPARTMENTS News of the Sections ...... 839 Advertiser Internet Directory...... 849 Sound Track...... 844 In Memoriam ...... 850 Upcoming Meetings ...... 844 AES Special Publications ...... 853 New Products and Developments...... 845 Sections Contacts Directory ...... 858 Available Literature ...... 847 AES Conventions and Conferences ...... 864 Membership Information...... 848 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 50 NUMBER 11 2002 NOVEMBER

CONTENT

PAPERS Estimation of Modal Decay Parameters from Noisy Response Measurements ...... Matti Karjalainen, Poju Antsalo, Aki Mäkivirta, Timo Peltonen, and Vesa Välimäki 867 Estimating decay parameters, such as room reverberation or string decay of musical instruments, becomes more inaccurate as the noise level increases if that noise is not also included in the parametric model. A new method based on nonlinear optimization of a linear model with additive noise is demonstrated as being more accurate than the traditional approaches, especially at extreme noise conditions. Several practical examples illustrate the utility of the proposed method. On the Use of TimeÐFrequency Reassignment in Additive Sound Modeling ...... Kelly Fitz and Lippold Haken 879 The conventional short-time spectral analysis is unable to parameterize signals that have both narrow- band components combined with transients because of the nature of the timeÐfrequency definition. Moreover, a single musical partial, which often has time-varying amplitude and frequency envelopes, does not appear as a single component in the classical linear analysis approach. By reassigning energy components, temporal smear is greatly reduced because unreliable data points can be removed from the representation. Several examples illustrate the ability to reconstruct abrupt onset square waves. Scalable Multichannel Coding with HRFT Enhancement for DVD and Virtual Sound Systems ...... M. O. J. Hawksford 894 Using the perceptual properties embedded in the head-related transfer functions of a normal listener, a standard five- or six-channel audio source can be transformed to feed additional loudspeakers, perhaps as many as 18. The proposed system enhances image stability by optimizing the correct ear signals at the listener’s location. The approach improves spatial resolution over a wider area while retaining backward compatibility with an unprocessed reproduction environment. Two-to-Five Channel Sound Processing...... R. Irwan and Ronald M. Aarts 914 In order to reproduce two-channel audio sources in a surround listening environment, the authors evaluated a proposed processing system based on decoding the principle directional component using correlation techniques. By parameterizing direction a stable center channel was created. Moreover, the synthesized ambiance for the sides does not degrade image stability.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 927 New Internet facilities; preservation of recordings; storage and handling; audio connectors; grounding and shielding; file exchange

FEATURES 113th Convention Report, Los Angeles...... 934 Exhibitors...... 950 Program...... 954 Bluetooth and Wireless Networking—A Primer for Audio Engineers...... 979 11th Tokyo Regional Convention, Call for Papers ...... 1001

DEPARTMENTS News of the Sections ...... 985 Membership Information...... 993 Sound Track...... 989 Advertiser Internet Directory...... 999 Upcoming Meetings ...... 990 In Memoriam ...... 1000 New Products and Developments...... 990 Sections Contacts Directory ...... 1002 Available Literature ...... 992 AES Conventions and Conferences ...... 1008 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 50 NUMBER 12 2002 DECEMBER

CONTENT President’s Message...... Kees Immink 1011 PAPERS Frequency-Zooming ARMA Modeling of Resonant and Reverberant Systems ...... Matti Karjalainen, Paulo A. A. Esquef, Poju Antsalo, Aki Mäkivirta, and Vesa Välimäki 1012 Complex linear, time-invariant modeling of a system with high modal density is extremely difficult, for example, room reverberation. A frequency-zooming method based on an extension of previous techniques is explored for high-resolution modeling of systems with many poles and zeros. Such models can be used not only to generate accurate time responses, but also to serve as the basis for inverse filtering and equalization. Passive All-Pass Crossover System of Order 3 (Low Pass) + 5 (High Pass), Incorporating Driver Parameters...... Neville Thiele 1030 A third-order low-pass channel combined with a fifth-order high-pass channel can be designed to produce an overall all-pass crossover between the two channels. Because the two channels are approximately in phase over the crossover region, the approach is more tolerant to variations in driver parameters and physical offsets in the cabinet. Although the approach adds a modest cost, the benefits appear to justify the incremental complexity. Experimental Evidence of Cooperation Phenomena Application to a Loudspeaker with Rub ...... Fernando Bolaños 1039 Unlike a linear system, which preserves the frequency integrity of each signal component, a nonlinear system can shift energy from one spectral component to another. Although the theoretical basis of energy cooperation is well known, the author empirically demonstrates the phenomena in an electroacoustic experiment involving a voice coil with friction. When random noise is added to a sine wave, the nonlinear process moves energy from the noise to the sine frequency. This is analogous to the way that a limit-cycle oscillator converts the dc of the power supply into a spectral component. ENGINEERING REPORTS Iterative Combinatorial Basis Spectra in Wavetable Matching ...... Alan Ng and Andrew Horner 1054 As an alternative to the combinatorial approach to wavetable synthesis, an iterative method is proposed to increase the computational efficiency while achieving a comparable effectiveness. The algorithm was evaluated using tones from the trumpet, tenor voice, and Chinese pipa (a plucked stringed instrument). The number of wavetables dramatically influenced the rms error. In addition, subjective listening tests determined the degree to which the synthesized signal was equivalent to the original. STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 1064 Calls for Comment: MADI revision, life expectancy of CD-ROM; Internet audio; audio metadata FEATURES Moving Digital Audio, Part 1...... 1068 2002/2003 AES International Sections Directory...... 1076 Education News...... 1106 Call for Nominations for Board of Governors ...... 1113 Call for Awards Nominations...... 1114 11th Tokyo Regional Convention, Call for Papers...... 1124 115th Convention, New York, Call for Papers ...... 1125 114th Convention, Amsterdam, Call for Workshops Participants ...... 1126 Bylaws: Audio Engineering Society, Inc...... 1127 Index to Volume 50...... 1132 DEPARTMENTS News of the Sections ...... 1101 AES Annual Report ...... 1115 Sound Track...... 1108 Membership Information...... 1116 New Products and Developments...... 1109 Advertiser Internet Directory...... 1119 Upcoming Meetings ...... 1110 In Memoriam ...... 1120 Available Literature ...... 1111 AES Conventions and Conferences ...... 1144 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 51 NUMBER 1/2 2003 JANUARY/FEBRUARY CONTENT

PAPERS Analysis of Traditional and Reverberation-Reducing Methods of Room Equalization ...... Louis D. Fielder 3 Unlike the traditional approach to room equalization, which compensates for the steady-state spectral effects, a true equalization method will become a dereverberator. Such an approach simultaneously removes the acoustic properties of the reproduction environment in both the frequency and time domains. It is a very difficult problem. Although the proposed solution proves to be impractical when employed in a real application, the analysis illuminates several critical criteria for evaluating any solution. New psychoacoustic metrics successfully predicted those degradations that made the system unacceptable. Kautz Filters and Generalized Frequency Resolution:Theory and Audio Applications ...... Tuomas Paatero and Matti Karjalainen 27 Most audio signal processing filters use a basic building block containing a delay or a pole, but other choices of orthonormal functions include the use of an all-pass block. When using this type of block, the resulting structures, called Kautz filters, readily allow frequency warping. Although this approach has been overshadowed by the more traditional methods, the authors show that lower order filters are needed when applied to loudspeaker equalization, room response modeling, and guitar body acoustics. The design phase is more complex, but there is no additional computation load at run time. Horn Acoustics: Calculation through the Horn Cutoff Frequency...... Peter A. Fryer 45 The author reconsiders the mathematical approach to analyzing exponential horn loudspeakers above and below the cutoff frequency. This work provides a more solid foundation for the simplified methods of partitioning the mathematics into two regions with different assumptions in each one. By introducing a tiny amount of acoustic loss into the model, the mathematics no longer break down when traversing the transition region at cutoff. The results agree with measured data. Modified Discrete Cosine Transform—Its Implications for Audio Coding and Error Concealment ...... Ye Wang and Miikka Vilermo 52 This study of the modified discrete cosine transform (MDCT) explores the implications of audio coding and error concealment from the perspective of Fourier frequency analysis. Subjective coding quality and the tolerance to missing or repeated compressed data blocks often produce contradictory requirements in real applications. Tradeoffs involve the selection of window-sized crossfade transitions between blocks and perception of uncancelled alias components. CORRECTIONS Correction to: “On the Use of TimeÐFrequency Reassignment in Additive Sound Modeling” ...... Kelly Fitz and Lippold Haken 62 STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 63 MADI; loudspeaker components; peak flutter; tape storage; CD-ROM life; loudspeaker polar data; digi- tal input-output interfacing; digital synchronization; media storage and handling; library and archive systems; forensic audio; audio connectors; shielding and EMC; audio over IEEE 1394 FEATURES 114th Convention Preview, Amsterdam...... 76 Calendar...... 78 Exhibitors...... 79 Exhibit Previews...... 81 Virtual and Synthetic Audio ...... 93 115th Convention, New York, Call for Papers...... 112 DEPARTMENTS News of the Sections ...... 99 Advertiser Internet Directory...... 109 Upcoming Meetings ...... 104 In Memoriam ...... 111 Sound Track...... 105 Sections Contacts Directory ...... 114 Available Literature ...... 106 AES Conventions and Conferences ...... 120 Membership Information...... 108 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 51 NUMBER 3 2003 MARCH CONTENT PAPERS Signal Representation Including Waveform Envelope by Clustered Line-Spectrum Modeling ...... M. Kazama, K.Yoshida, and M.Tohyama 123 When modeling a narrow-band signal, which includes spectral lines close to the peak, the effect of windowing truncation also appears in the region near the peak spectral line. By extending previous research, the authors propose a method to model the spectrum near peaks. This requires an interpolation to find the peak, peak picking, and a model of the effect of windowing in order to extract the slowly varying envelope information. Several examples of audio signals with noise, called clustered line-spectrum modeling, are used to demonstrate practical applications of the approach.

ENGINEERING REPORTS A Moving-Horizon Optimal Quantizer for Audio Signals ...... Graham C. Goodwin, Daniel E. Quevedo, and David McGrath 138 Quantizing, or requantizing a previously digitized signal, produces errors that are perceived as noise. While a time-invariant noise-shaping feedback can move the noise spectrum to a region of less sensitivity, this conventional approach is actually a subset of a more general method. In the proposed extension, quantization decisions use a perceptual model that also analyzes future samples. A look ahead of only three samples, called a moving horizon, is sufficient to produce even lower perceived noise without adding significant computational complexity. Test Signal Generation and Accuracy of Turntable Control in a Dummy-Head Measurement System ...... György Wersényi and András Illényi 150 Unlike the typical application, ultrahigh-accuracy measurements of the head-related transfer function are required when studying the influence of small changes in the acoustic environment near the head. To achieve the needed accuracy, the normal measurement method was modified. Low-crest factor, pseudo- random noise sequences replaced the conventional impulse, and the turntable positioning of the dummy head was modified for high-positional repeatability. Loudspeaker Equalizer Design for Near-Sound-Field Applications ...... Wee Ser, Peng Wang, and Ming Zhang 156 Single-user loudspeaker presentation venues, such as those found in transaural and binaural systems or in personal computers, can not benefit from the conventional form of frequency response equalization. Those optimizations are on-axis signal, average power, or some other generic metric. Single-user applications benefit by optimizing the sound at the listener’s two ears in the near field and no other place. The proposed method demonstrates an equalization method that improves absolute accuracy at both ears and minimizes differential errors between the two ears.

LETTERS TO THE EDITOR Comments on “A Simplified Wavetable Matching Method Using Combinatorial Basis Spectra Selection” ...... Robert Bristow-Johnson 162 Author’s Reply ...... Andrew Horner 163 STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 164 Analog recording; loudspeaker modeling and measurement; audio file transfer; Internet audio delivery; audio metadata

FEATURES 23rd Conference Preview, Copenhagen ...... 170 Calendar...... 172 Program...... 174 Registration Form ...... 179 Moving Digital Audio, Part 2—File Transfer...... 180

DEPARTMENTS News of the Sections ...... 188 Membership Information...... 198 Upcoming Meetings ...... 192 Advertiser Internet Directory...... 200 Sound Track...... 193 Sections Contacts Directory ...... 202 New Products and Developments...... 195 AES Conventions and Conferences ...... 208 Available Literature ...... 197 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 51 NUMBER 4 2003 APRIL CONTENT PAPERS The Bidirectional Microphone: A Forgotten Patriarch ...... Ron Streicher and Wes Dooley 211 After reviewing the history and general issues of microphones and their sensitivity patterns, the authors focus on a pure bidirectional microphone. It is the most difficult to use. Specifically, its major virtue is the ability to place nulls at orientations to suppress unwanted sound pickup. All microphone patterns can be described in terms of a combination of an omnidirectional and figure-of-eight pattern. Many common sense rules are discussed to avoid accidental destruction of microphones’ ribbons. Efficient Tempo and Beat Tracking in Audio Recordings ...... Jean Laroche 226 Automatically measuring musical beat is useful in sound analysis, crossfade synchronization, and audio editing. A proposed off-line system works well for music that has a relatively pronounced beat, yet without creating burdensome demands on computational resources. The algorithm is based on detecting rapid changes in energy within a short-term frequency representation. This produces a more reliable approach because overall energy can mask those spectral components that govern the perception of a beat. A least-square optimization then identifies the best tempo and downbeat location. On the Acoustic Radiation from a Loudspeaker’s Cabinet...... Kevin J. Bastyr and Dean E. Capone 234 Although it is well known that the walls of a loudspeaker cabinet vibrate at low frequencies, the authors determined the actual sound energy being radiated. Initially, a vibrometer was used to measure the surface velocity along the surface, and then a boundary-element method was used to model the acoustic radiation. By applying this method to production loudspeakers, changes in the internal bracing allow the designers to control these unwanted surface resonances, which are true radiating sources. The effects of enclosure vibration affect the overall radiation pattern of the loudspeaker and must be included in the design.

ENGINEERING REPORTS The Virtual Loudspeaker Cabinet ...... J. R. Wright 244 The effective volume of a loudspeaker cabinet can be enlarged by as much as a factor of 3 if activated carbon is included inside the enclosure. The acoustic compliance, the ratio of change in volume with increased pressure, increases because the carbon absorbs and desorbs air. While it is still not commercially viable, the author demonstrates a successful laboratory model, which was judged to sound like a larger cabinet. Special care is needed to ensure that the carbon is uniformly distributed and that it does not absorb water.

LETTERS TO THE EDITOR Comments on “Dipole Loudspeaker Response in Listening Rooms” and “Perception of Reverberation Time in Small Listening Rooms”...... Tomas Salava 248 Author’s Reply ...... James M. Kates 250 Author’s Reply ...... W. J. Davies 251 Comments on “President’s Message”...... David Lloyd ben Yaacov Yehuda Klepper 251 Author’s Reply...... Kees A. S. Immink 251

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 253 Plane-wave tubes; MAD; acoustics and sound-source modeling; microphone measurement and characterization; listening tests

FEATURES 24th Conference Preview, Banff...... 258 Calendar...... 260 Program ...... 262 Registration Form ...... 271 MIDI and Musical Instrument Control ...... 272 Game Audio: Follow-up to Workshop at 113th Convention ...... 277

DEPARTMENTS Review of Acoustical Patents...... 256 Membership Information...... 289 News of the Sections ...... 279 In Memoriam ...... 290 Upcoming Meetings ...... 285 AES Special Publications ...... 293 Sound Track ...... 286 Sections Contacts Directory ...... 298 New Products and Developments ...... 287 AES Conventions and Conferences ...... 304 Advertiser Internet Directory...... 288 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 51 NUMBER 5 2003 MAY

CONTENT

PAPERS Assessment of Voice-Coil Peak Displacement Xmax...... Wolfgang Klippel 307 Peak voice-coil displacement is an important parameter for specifying the maximum acoustic output at low frequencies. However, the absence of a single definition for distortion produces ambiguous results that can not be easily compared. For example, choices include distortion in the voice-coil current or cone displacement. Alternatively, a parametric method that provides more detailed information about the cause of the distortion is proposed. A comparison between performance-based and parameter-based techniques illustrates the advantages and disadvantages. Modal Equalization of LoudspeakerÐRoom Responses at Low Frequencies ...... Aki Mäkivirta, Poju Antsalo, Matti Karjalainen, and Vesa Välimäki 324 Compensation for the dominant low-frequency modes in small rooms traditionally uses equalization filters in cascade with the main sound source. In an alternative implementation, multiple sources produce better modal cancellation when traditional methods fail. Case studies show that the extra degrees of spatial freedom afforded by the additional sources make the system more robust. Modal equalization is a design option when the modal density is not high and when the modes are low frequency. It can also be combined with cascade equalization. A Low-Cost Intensity Probe ...... R. Raangs, W. F. Druyvesteyn, and H.-E. de Bree 344 Unlike ordinary microphones, a sound intensity probe measures the energy flow as a vector direction. It can be computed as the product of scalar pressure and vector velocity. In a conventional probe, velocity is computed as the difference in pressure at a small fixed distance. The authors propose a novel means of directly measuring velocity using the temperature difference between two heated wires mounted in a microminiaturized substrate. When combined with a standard pressure sensor, the probe measures sound intensity over the full spectrum at a single point in space. The paper provides examples of several methods for calibration of the particle velocity sensor used, such as in a standing-wave tube, reverberant room, anechoic space, and reverberation room. Two examples of sound-intensity measurements are provided and are compared with a conventional sound intensity probe.

ENGINEERING REPORTS Industry Evaluation of In-Band On-Channel Digital Audio Broadcast Systems...... David Wilson 358 The proposed techniques for terrestrial broadcasting of digital audio from iBiquity were evaluated using standard metrics: coverage, compatibility, interference, and quality. In order to maintain compatibility with existing AM and FM analog broadcasting, digital information was added as low-amplitude side bands around the main analog spectrum. While the proposed solution achieves the desired goal of preserving the existing competitive balance between radio broadcasters, there is an additional interference outside the protected geographic region. Subjective listening tests confirmed that digital audio improved the quality even at reduced bit rates.

STANDARDS AND INFORMATION DOCUMENTS AES46-2002 AES standard for network and file transfer of audio — Audio-file transfer and exchange — Radio traffic audio delivery extension to the broadcast WAVE file format ...... 369 AES Standards Committee News...... 384 Julian Dunn; resonance of loudspeaker cones

FEATURES 114th Convention Report, Amsterdam ...... 386 Exhibitors...... 402 Program...... 405

TECHNICAL COUNCIL REPORTS Technical Committee Reports: Emerging Trends in Technology ...... 442

DEPARTMENTS News of the Sections ...... 452 Available Literature ...... 461 Upcoming Meetings ...... 458 Membership Information...... 463 Advertiser Internet Directory...... 459 In Memoriam ...... 465 Sound Track...... 460 Sections Contacts Directory ...... 466 New Products and Developments...... 460 AES Conventions and Conferences ...... 472 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 51 NUMBER 6 2003 JUNE

CONTENT

PAPERS Effects of Bandwidth Limitation on Audio Quality in Consumer Multichannel Audiovisual Delivery Systems...... Slawomir⁄ K. Zieli«nski, Francis Rumsey, and S¿ren Bech 475 When transmitting or storing 5.1 program material, if bandwidth must be sacrificed to accommodate channel limitations, the rear surround and the front center channels are the best choices. As long as the front left and right channels maintain the full spectrum, subjective degradation is minimal. Extensive subjective tests support this conclusion even if the bandwidth-limited channels contain foreground audio content. An Efficient Algorithm for the Restoration of Audio Signals Corrupted with Low-Frequency Pulses ...... Paulo A. A. Esquef, Luiz W. P.Biscainho, and Vesa Välimäki 502 Restoring old recordings, especially those that contain clicks at the boundaries where pieces of a broken record have been glued together, requires a model of the corruption. In addition to the transient itself, the cartridge responds to the transient with a long-tailed, low-frequency impulse response, which must also be removed. The authors propose a computationally efficient algorithm, called two-pass split-window filtering, to model and remove this additional component. The results are compared with an autoregressive algorithm.

ENGINEERING REPORTS Study on the Relationship between Some Room Acoustical Descriptors ...... D. Ouis 518 An acoustic model of a performance space provides a means for evaluating those physical measures that predict the subjective experience, such as spaciousness. In order to evaluate the relationship between the various metrics over the space, the author simulated a rectangular space with an additional pair of sidewall balconies. Image reflections and diffraction effects were included to make the model more representative of a real space. This allowed the relationship among parameters to be evaluated. Automated Parameter Optimization for Double Frequency Modulation Synthesis Using a Tree Evolution Algorithm...... B. T. G. Tan and N. Liu 534 As a means of synthesizing complex sounds, several frequency modulation techniques have become popular. However, finding the ideal frequency and amplitude modulation waveforms to create a target signal is difficult, ad hoc, and prone to nonoptimum results. Many optimization algorithms tend to converge to a local solution without adequately exploring the entire space for better solutions. The proposed approach separately explores each local solution rather than focusing on a single part of the space.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 547 Level meters; digital interfacing; digital synchronization; forensic audio; microphone measurements; audio applications of IEEE 1394

FEATURES History of Spatial Coding ...... Mark F. Davis 554 Automotive Audio...... 570 New Media for Music: An Adaptive Response to Technology ...... 575 Updates and Corrections to the 2002/2003 International Sections Directory...... 578 Education News...... 580 116th Convention, Berlin, Call for Papers...... 596

DEPARTMENTS News of the Sections ...... 582 Advertiser Internet Directory...... 593 Upcoming Meetings ...... 587 In Memoriam ...... 594 Sound Track...... 588 AES Special Publications ...... 597 New Products and Developments...... 589 Sections Contacts Directory ...... 602 Available Literature ...... 591 AES Conventions and Conferences ...... 608 Membership Information...... 592 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 51 NUMBER 7/8 2003 JULY/AUGUST CONTENT PAPERS Full-Sphere Sound Field of Constant-Beamwidth Transducer (CBT) Loudspeaker Line Arrays ...... D. B. (Don) Keele, Jr. 611 Unlike a linear-line array of loudspeakers, which has no means of controlling the horizontal beamwidth, a curved-line circular-arc array exhibits useful properties in three dimensions. Based on a computer simulation, the author shows that the configuration provides horizontal directivity in addition to the expected vertical control. Such arrays have a pear-shaped pattern that is surprisingly uniform over the frequency range. The bending is an extra degree of freedom that allows more control over the radiation pattern. Direct-Radiator Loudspeaker Systems with High Bl ...... John Vanderkooy, Paul M. Boers, and Ronald M. Aarts 625 Increasing the magnetic motor strength of a driver not only improves the efficiency of the loudspeaker and amplifier, but also improves other tradeoffs in the design process. Box volume can be decreased. A study demonstrated the advantages for a small sealed-box configuration, although equalization is required to restore a flat response. Vented systems do not benefit as much from this approach. Psychoacoustic Investigations On Sound-Source Occlusion ...... Hania Farag, Jens Blauert, and Onsy Abdel Alim 635 Virtual space simulation is actually a collection of acoustic attributes, which include objects that cast auditory shadows, an effect known as occlusion. Objects block and change the perception of sound when they are located between the source and the listener. Experiments show that the perceived location of an occluded source is shifted to the edge closest to the listener, which simplifies the computational burden of modeling occluding objects. This result is consistent with the precedence effect. ENGINEERING REPORTS The Differential Pressure Synthesis Method for Efficient Acoustic Pressure Estimation ...... Yufei Tao, Anthony I. Tew, and Stuart J. Porter 647 Calculating the sound field around a complex object, such as the pressure at the two ears of a head, is computationally intensive. Rather than a direct computation, the authors demonstrate an incremental approach to a reference template. The pressure changes produced by each spherical harmonic are precomputed and stored in a database. The target shape is then decomposed into the template references and the sum of spherical harmonics, each of which contributes an incremental change to the pressure. In the case of a dummy head, the results were accurate for wavelengths that were large compared to the spatial perturbations. LETTERS TO THE EDITOR Comments on “Deciphering an Enigma” ...... Marianna Sankiewicz and Gustaw Budzy«nski 657 Author’s Reply to “Comments on ‘Deciphering an Enigma’” ...... Steven Harris 657 STANDARDS AND INFORMATION DOCUMENTS AES47-2002 AES standard for digital audio—Digital input–output interfacing—Transmission of digital audio over asynchronous transfer mode (ATM) networks ...... 659 AES-R4-2002 AES standards project report—Guidelines for AES standard for digital audio— Digital input–output interfacing—Transmission of digital audio over asynchronous transfer mode (ATM) networks, AES47...... 684 AES Standards Committee News...... 704 Mechanical media; audio storage and handling; listening tests; audio connectors; grounding and EMC; audio file transfer and exchange FEATURES 115th Convention Preview, New York...... 714 Calendar...... 716 Exhibitors...... 717 Exhibit Previews...... 722 Demystifying Audio Metadata ...... 744 116th Convention, Berlin, Call for Papers...... 768 25th Conference, London, Call for Papers ...... 769 DEPARTMENTS Review of Acoustical Patents...... 710 Membership Information...... 759 News of the Sections ...... 752 Advertiser Internet Directory...... 762 Sound Track...... 756 In Memoriam ...... 766 Available Literature ...... 757 Sections Contacts Directory ...... 770 Upcoming Meetings ...... 758 AES Conventions and Conferences ...... 776 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 51 NUMBER 9 2003 SEPTEMBER

CONTENT In Memoriam: Patricia Macdonald ...... Roger K. Furness 779

PAPERS Effects of Down-Mix Algorithms on Quality of Surround Sound ...... Slawomir⁄ K. Zieli«nski, Francis Rumsey, and S¿ren Bech 780 When channel limitations prevent the transmission of a full 5.1 surround mix, there are many options for converting to a lesser number of channels using down mixing. Listeners were asked to evaluate eight different algorithms from two listening positions in terms of preferences rather than quality. Unfortunately, different audio cases produced variations in the conclusion about optimum. The presence of a video picture influenced the experience of reduced audio channels. A Study on Head-Shape Simplification Using Spherical Harmonics for HRTF Computation at Low Frequencies ...... Yufei Tao, Anthony I.Tew, and Stuart J. Porter 799 Using a simplified shape for the human head in computing head-related transfer functions (HRTFs) produces errors in the calculated pressures on the surface. A model of a head can be represented as a series of spherical harmonics. This study computes the errors in acoustic pressure that result from truncating the series, which corresponds to low-pass shape filtering. These shape errors follow the corresponding pressure errors for frequencies below 3 kHz. Harmonics to order 11 are sufficient for the low frequencies representation of a head. Beyond order 14 there is no additional improvement. Differences in Performance and Preference of Trained versus Untrained Listeners in Loudspeaker Tests: A Case Study ...... Sean E. Olive 806 The audio industry makes many assumptions about the appropriateness of various quality testing methods, but there have not been any significant studies to validate these assumptions. The choices are reduced to using trained listeners, who are efficient and discriminating, or untrained listeners, who are more representative of the user population. This 18-month study shows that trained listeners produce the same conclusion as 268 untrained listeners when evaluating loudspeakers. Objective Measures of Listener Envelopment in Multichannel Surround Systems ...... Gilbert A. Soulodre, Michel C. Lavoie, and Scott G. Norcross 826 Predicting the degree of listener envelopment is more complex than the traditional measures of lateral energy after the first 80 ms. This detailed study shows that the transition threshold between early and late energy is frequency-dependent. In addition, the loudness of the lateral energy is equally important. A new objective measure is proposed with a very high correlation between perceived envelopment and the calculated metric.

LETTERS TO THE EDITOR “More Comments on President’s Message and Comments” ...... John Woodgate 841

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 842 Sampling frequencies; digital audio synchronization; preservation and restoration of recordings; loudspeaker modeling and measurement

FEATURES 23rd Conference Report, Copenhagen ...... 846 Digital Rights Management...... 855 25th Conference, London, Call for Papers ...... 871

DEPARTMENTS News of the Sections ...... 861 Membership Information...... 872 Sound Track...... 865 Advertiser Internet Directory...... 873 New Products and Developments...... 867 Sections Contacts Directory ...... 874 Upcoming Meetings ...... 868 AES Conventions and Conferences ...... 880 Available Literature ...... 869 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 51 NUMBER 10 2003 OCTOBER

CONTENT

PAPERS Two-Port Representation of the Connection between Horn Driver and Horn ...... Gottfried K. Behler and Michael Makarski 883 Analyzing a loudspeaker system comprised of a horn and a horn driver is more productive if each element is modeled with an approach that is appropriate to the underlying physics. The driver element approximates a classical two port, with electrical voltage and current at the input port and acoustic pressure and velocity at the output port. In contrast, the horn element incorporates a three-dimensional sound radiation pattern with a one-dimensional acoustic input. The model of each element was merged at the connection point to predict the performance of the system’s combination.

ENGINEERING REPORTS Sensitivity of High-Order Loudspeaker Crossover Networks with All-Pass Response ...... Brandon Cochenour, Carlos Chai, and David A. Rich 898 While component tolerances influence the properties of loudspeaker crossover networks and these influences are greatest in high-order filters, the advantages of high-order networks dwarf other issues. Specifically as a listener changes his elevation, the shift in delay among noncoincident drivers dominates the frequency response. High-order filters limit this influence to a narrow-frequency region. Monte Carlo simulations confirmed that the component tolerances, in comparison to delay changes, are a minor aspect of the response.

Wavefront Sculpture Technology...... Marcel Urban, Christian Heil, and Paul Bauman 912 Arrays of discrete loudspeakers are useful for creating a controlled sound field over a wide area, but mathematical and numeric methods often do not provide intuitive insight into the physical process. Using the visual analog of a Fresnel analysis, the authors considered a qualitative approach to the design of loudspeaker arrays to show how interference can be controlled. When this approach was applied to a curved array, the added degree of freedom enabled a wave field to be created that is free of destructive interference over a larger predefined area.

Acoustical Renovation of Tainan Municipal Cultural Center Auditorium ...... Weihwa Chiang, Chingtsung Hwang, and Yenkun Hsu 933 The Tainan auditorium had a reputation for good acoustics, but its reverberation time and spatial acoustics were inadequate for orchestra performances. Because the ceiling had been damaged, the renovation project also offered an opportunity to modify the acoustics. Scale models of the proposed changes were used to compare the conditions before and after the renovation. Simple modifications of the space produced dramatic improvements.

FEATURES 24th Conference Report, Banff...... 946 Advances in Low Bit-Rate Audio Coding ...... 956 Review of Society’s Sustaining Members ...... 965 Updates and Corrections to the 2002/2003 International Sections Directory...... 983

DEPARTMENTS Review of Acoustical Patents...... 943 Available Literature ...... 992 News of the Sections ...... 985 Membership Information...... 993 Sound Track...... 988 AES Special Publications ...... 997 Upcoming Meetings ...... 988 Sections Contacts Directory ...... 1002 New Products and Developments...... 989 AES Conventions and Conferences ...... 1008 Advertiser Internet Directory...... 991 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 51 NUMBER 11 2003 NOVEMBER CONTENT President’s Message ...... Ron Streicher 1011

PAPERS The Effect of Nonlinear Distortion on Perceived Quality of Music and Speech Signals ...... Chin-Tuan Tan, Brian C. J. Moore, and Nick Zacharov 1012 The subjective evaluation of nonlinear distortions often shows a weak correlation with physical measures because the choice of distortion metrics is not obvious. In reexamining this subject, the authors validated a metric based on the change in the spectrum in a series of spectral bins, which when combined leads to a single distortion metric. Distortion was evaluated both objectively and subjectively using speech and music. Robust results support the hypothesis for this approach.

ENGINEERING REPORTS Ultra-High Quality Video Frame Synchronous Audio Coding ...... Michael J. Smithers, Brett G. Crockett, and Louis D. Fielder 1032 When audio signals accompany video information, additional requirements are imposed on audio encoding to allow for frame-based video editing, switching, and splicing. Moreover within the bit budget, the number of channels and their bit allocation is flexible. In the proposed approach audio blocks are designed to match the frame boundaries, but with an additional transitional region that avoids time-domain aliases, a degradation resulting when neighboring blocks are no longer contiguous. Large-Signal Analysis of Triode Vacuum-Tube Amplifiers...... Muhammad Taher Abuelma’atti 1046 With the renewed interest in vacuum tubes, the issue of intrinsic distortion mechanisms becomes relevant again. The author demonstrates a nonlinear model of triodes and pentodes that leads to a closed-form solution when the nonlinearity is represented by a Fourier expansion rather than the conventional Taylor series. When applied to a two-tone sine wave, the analysis shows that the distortion in tube amplifiers is similar to that of the equivalent transistor amplifier. A SPICE analysis confirms the approach. Acoustical Measurements of Traditional Theaters Integrated with Chinese Gardens ...... Weihwa Chiang, Yenkun Hsu, Jinjaw Tsai, Jiqing Wang, and Linping Xue 1054 The acoustics of three Chinese theaters from the nineteenth century were evaluated using the conventional metrics for performance spaces. Similar to the Western tradition, theaters evolved as one of three types: amphitheater, courtyard, and auditorium. However, Chinese theaters were often integrated with privately owned gardens with a diversified design and acoustic architecture. Even with a high degree of spatial irregularity, measurements were consistent with modern theater acoustics.

LETTERS TO THE EDITOR Comments on “History of Spatial Coding”...... Peter Scheiber 1062 Why Is Bass Reproduction from a Dipole Woofer in a Living Room Often Subjectively More Accurate Than from a Monopole Woofer? ...... Siegfried Linkwitz 1062

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 1064 Standards in print

FEATURES Binaural Audio in the Era of Virtual Reality ...... 1066 New Officers 2003/2004...... 1073 2003/2004 AES International Sections Directory...... 1078

DEPARTMENTS News of the Sections ...... 1104 Membership Information...... 1111 Sound Track...... 1108 Advertiser Internet Directory...... 1112 New Products and Developments...... 1108 AES Special Publications ...... 1115 Upcoming Meetings ...... 1109 AES Conventions and Conferences ...... 1120 Available Literature ...... 1110 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 51 NUMBER 12 2003 DECEMBER CONTENT PAPERS Why Are Commercials so Loud? — Perception and Modeling of the Loudness of Amplitude- Compressed Speech...... Brian C. J. Moore, Brian R. Glasberg, and Michael A. Stone 1123 According to urban legend, commercials are broadcast with higher loudness levels than programming. An empirical study confirmed that four-band compressed speech sounds louder than uncompressed speech by as much as 3 dB when the rms levels are matched. An audio engineer can control only the perceived loudness of broadcast program material if a loudness meter is available for monitoring the program. However, loudness models require significant computational power if used in real time. Smart Digital Loudspeaker Arrays ...... M. O. J. Hawksford 1133 With the advent of microminiature transducers, a new class of loudspeaker design fundamentals is required in order to implement programmable radiation beam directions and beamwidths. The primary objective of this study was to develop a processing strategy to obtain a target directional radiation from an array of transducers, each with its own dedicated signal processing. Coherent and diffuse beams can be obtained simultaneously from the same array over a wide frequency range. Localization of 3-D Sound Presented through Headphone—Duration of Sound Presentation and Localization Accuracy...... Fang Chen 1163 Of all the spatial parameters that influence localization accuracy, signal duration is often one of the most important. When the duration is long enough, approaching four seconds, accuracy using headphones is comparable to that of free-field or individual HRTFs. The results of this empirical study are consistent with a wide variety of sound samples. Designers of auditory displays must include signal duration as an important parameter. ENGINEERING REPORTS Reconstruction of Mechanically Recorded Sound by Image Processing ...... Vitaliy Fadeyev and Carl Haber 1172 Two-dimensional image processing offers a modern method to reproduce historic mechanical recordings without using a contact transducer. Moreover, because image processing uses information spread over a wide area, it is easier to remove noise, scratches, and other defects. In addition to avoiding additional degradation by contact transducers, optical decoding of groove undulations produces better audio quality. A contact transducer senses mechanical position at a single point in space and time, an image incorporates mechanical information spanning a large area. This approach may allow automated preservation of endangered audio performances of historic value. LETTERS TO THE EDITOR Comments on “Analysis of Traditional and Reverberation-Reducing Methods of Room Equalization”...... John N. Mourjopoulos 1186 Author’s Reply...... Louis D. Fielder 1189 CORRECTIONS Correction to: “Effects on Down-Mix Algorithms on Quality of Surround Sound” ...... S. K. Zieli«nski, F. Rumsey, and S. Bech 1192 STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 1193 Digital audio synchronization; listening tests; Internet audio quality FEATURES 115th Convention Report, New York...... 1196 Exhibitors ...... 1210 Program...... 1215 11th Tokyo Regional Convention Report...... 1258 Exhibitors ...... 1261 Program...... 1262 Education News...... 1276 Call for Nominations for Board of Governors ...... 1282 Call for Awards Nominations...... 1283 Bylaws: Audio Engineering Society, Inc...... 1289 Index to Volume 51...... 1293 DEPARTMENTS News of the Sections ...... 1271 Advertiser Internet Directory...... 1286 Sound Track...... 1279 In Memoriam ...... 1287 Upcoming Meetings ...... 1279 AES Special Publications ...... 1317 New Products and Developments...... 1280 Sections Contacts Directory ...... 1322 Available Literature ...... 1281 AES Conventions and Conferences ...... 1328 Membership Information...... 1285 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 52 NUMBER 1/2 2004 JANUARY/FEBRUARY

CONTENT

PAPERS Nonlinear Modeling of the Heat Transfer in Loudspeakers ...... Wolfgang Klippel 3 Traditional analysis of a loudspeaker assumes that thermal and electromechanical models can be represented by linear coupling. Careful examination with a variety of music samples shows that such a model fails to produce accurate results because both systems are intrinsically nonlinear. Especially at low frequencies, the cone movement produces cooling and lower temperatures. A linear approach considers only the input power to the thermal model, while a nonlinear approach includes displacement, velocity, and two components of power dissipation. The nonlinear model is more accurate. Simultaneous Measurement of Multichannel Acoustic Systems ...... Alberto González, Pedro Zuccarello, Gema Piñero, and María de Diego 26 Measuring the linear properties of a multichannel audio system can be viewed as a collection of single- channel systems if each channel is measured in isolation. With a large number of input and output channels, a sequential measurements approach takes increasing amounts of time. Using time or frequency multiplexing allows all measurements to be performed simultaneously. A theoretical framework shows the validity of this approach. A New Thermal Model for Loudspeakers ...... Fabio Blasizzo 43 Conventional models of temperature in loudspeakers usually ignore the transport of heat from the forced- air convection cooling produced by movement of the loudspeaker cone. Especially at low frequencies in large , force ventilation is the dominant mechanism for heat transport. Because high temperatures produce distortion and degradation, designers need an accurate means of including thermal tradeoffs. Simulation results show that the new model predicts voice-coil temperature more accurately.

ENGINEERING REPORTS Effect of Arrival Time Correction on the Accuracy of Binaural Impulse Response Interpolation— Interpolation Methods of Binaural Response ...... Mitsuo Matsumoto, Susumu Yamanaka, Mikio Toyama, and Hiroaki Nomura 56 When attempting to create a head-related transfer function (HRTF) for a source that can have a continuous location, spatial HRTFs at discrete locations are generally interpolated to get the desired response. Numerous methods of interpolation have already been investigated, but if the methods include time correction, accuracy is improved. Angular shifts in the source location, in addition to changing the response’s fine structure, also produce a small time shift because the ears are not located at the center of the head. Azimuth changes produce a time shift.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 62 Secretariat note; peak levels; digital input/output interfacing; storage and handling of media; acoustics and sound source modeling

FEATURES New Horizons in Listening Test Design...... 65 Novel Surround Sound Microphone and Panning Techniques ...... 74 Updates and Corrections to the 2003/2004 International Sections Directory...... 81 117th Convention, San Francisco, Call for Papers...... 99

DEPARTMENTS News of the Sections...... 84 Advertiser Internet Directory...... 95 Sound Track ...... 90 In Memoriam ...... 96 New Products and Developments...... 91 AES Special Publications ...... 101 Upcoming Meetings ...... 92 Sections Contacts Directory ...... 106 Available Literature...... 93 AES Conventions and Conferences ...... 112 Membership Information...... 94 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 52 NUMBER 3

CONTENT

INTRODUCTION High-Resolution Audio...... Rhonda J. Wilson 116

PAPERS Coding for High-Resolution Audio Systems...... J. Robert Stuart 117 To achieve the highest audio quality, one must consider not only each component of the chain but also the entire chain as a system. Furthermore, quality acquires a meaning that depends on the goals, application, and cost tradeoff. Choices for each element—such as sampling rate, encoding format, word size, filtering, and noise floors—may or may not influence the auditory quality of the total system. A review of various channel-coding methods within the context of auditory perception illustrates the principle of a “coding space,” which is the amount of useful information preserved or destroyed. For example, in an archival application the encoding noise floor should be at least two bits lower than the self-noise of the best audio signal.

Audio Analog-to-Digital Converters...... Mike Story 145 By considering the requirements for audio conversion within the wider context of conversion applications, we can better appreciate the implication of choosing a particular approach. Choices include: one bit versus multibit, use of feedback or multistage sequential processing, and switched capacitor versus continuous time. A review of the resulting performance shows the delicate balance among such parameters as accuracy, frequency, and burdens on implementation.

Future Design Challenges for Audio Converter Products ...... Julian Hayes, John Pennock, and Anthony Magrath 159 Extensive discussion about the theoretical limits of various digital conversion techniques, while interesting, ignore the practical implications of implementation difficulties. Physical devices, under economic pressure from the requirement of high yield and low expense, degrade performance to a significant degree. Chip designers must contend with timing errors, substrate noise, internal crosstalk, mismatched components, temperature gradients, nonlinear slew rates, wiring inductance, nonuniform doping, impurities, and numerous other issues. Special processes and computer modeling help reduce these corrupting influences, but problems still remain when attempting to achieve performance to the theoretical limits.

One-Bit Audio: An Overview ...... Derk Reefman and Erwin Janssen 166 While the CD format solidified full digital words of 16 to 24 bit as an audio coding standard, digital conversion technology moved toward oversampling using a few bits or only one bit. By using noise shaping within a sigmaÐdelta modulator, one-bit conversion can produce very high-quality audio. A review of the various implications leads to the conclusion that one-bit coding is an attractive approach rather than converting to the traditional pulse-code modulation.

Lossless Compression of One-Bit Audio ...... Eric Knapen, Derk Reefman, Erwin Janssen, and Fons Bruekers 190 Because the goal of the Super Audio CD is to produce the highest quality, lossless compression offers a way to reduce the storage capacity without sacrificing quality. A proposed design produces compression by using a prediction filter operating on a one-bit audio stream and then uses a probability lookup table to achieve a compression rate greater than 2.5:1 on typical music samples. However, the benefits produce a small uncertainty in playing time. Instantaneous compression rate varies dramatically over the extremes of peak transients or noise and intervals of silence.

Pulse-Code Modulation—An Overview...... Stanley P. Lipshitz and John Vanderkooy 200 The authors provide an overview of pulse-code modulation. They graphically demonstrate the properties of sampling and reconstruction, establishing that PCM allows band-limited signals to be time accurate to infinite precision. Any bandwidth can be accommodated with proper choice of the sampling frequency. The JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 52 NUMBER 4 2004 APRIL CONTENT President’s Message ...... Ron Streicher 331

PAPERS Graphing, Interpretation, and Comparison of Results of Loudspeaker Nonlinear Distortion Measurements...... Alexander Voishvillo, Alexander Terekhov, Eugene Czerwinski, and Sergei Alexandrov 332 For loudspeaker nonlinearity, measurement techniques range from single-tone harmonic distortion, which is easy to interpret but not indicative of performance with music, to reactions to multitone stimuli, which are hard to interpret but highly informative. Because multitone techniques have the potential to predict the perception of nonlinearities, the authors focus on various presentation formats and analysis techniques to make the relevant information in the thousands of intermodulation products accessible and meaningful.

ENGINEERING REPORTS Impedance Compensation Networks for the Lossy Voice-Coil Inductance of Loudspeaker Drivers...... W. Marshall Leach, Jr. 358 The high-frequency rise in the voice-coil impedance of a loudspeaker driver produced by lossy voice-coil inductance can be approximately cancelled by a Zobel network connected in parallel. Such networks improve performance by presenting purely resistive impedance to the crossover network. Although higher order networks can be used, a pair of resistors and capacitors is sufficient for typical drivers. Scalable, Content-Based Audio Identification by Multiple Independent Psychoacoustic Matching ...... Geoff R. Schmidt and Matthew K. Belmonte 366 A software audio search system, as an analog to text searching, allows a target music sample to be identified by matching it to a database containing an inventory of reference samples. Rather than rely on autonomous metadata, the algorithm uses a sequence of vectors based on perceptual attributes. By iteratively testing a progression of such vectors, the algorithm has the ability to trade accuracy versus compute time. With increasing storage capacity to hold virtually unlimited quantities of audio data, an efficient search algorithm is a necessity. On the Detection of Melodic Pitch in a Percussive Background ...... Preeti Rao and Saurabh Shandilya 378 Although many pitch detection algorithms have been proposed over the years, the problem is particularly difficult when melodic instruments are accompanied by percussive background. The authors propose a temporal autocorrelation pitch detector motivated by an auditory model that attempts to suppress errors produced by inharmonic interfering partials of such instruments as a kick drum. Separate processing of frequency channels proved crucial in reducing the distortion products, due to the nonlinear hair-cell model, between the signal harmonics and the interfering partials.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 392 New AESSC chairman; audio file interchange; audio over IEEE 1394

FEATURES 25th Conference Preview, London ...... 402 Calendar...... 404 Program ...... 405 Registration Form ...... 411 Historical Perspectives and Technology Overview of Loudspeakers for Sound Reinforcement ...... J. Eargle and M. Gander 412 DSP in Loudspeakers...... 434 Surround Live Summary...... Frederick Ampel 440 26th Conference, Baarn, Call for Papers ...... 457

DEPARTMENTS Review of Acoustical Patents...... 395 Membership Information...... 451 News of the Sections...... 443 Advertiser Internet Directory...... 453 Upcoming Meetings ...... 447 In Memoriam ...... 456 Sound Track ...... 448 Sections Contacts Directory ...... 458 New Products and Developments...... 449 AES Conventions and Conferences ...... 464 Available Literature...... 450 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 52 NUMBER 5 2004 MAY

CONTENT

PAPERS Analysis of Loudspeaker Line Arrays ...... Mark S. Ureda 467 A set of mathematical expressions is provided to estimate the performance of loudspeaker line arrays. These include expressions for the polar response, on-axis and off-axis pressure responses, and two-dimensional pressure fields of straight-line, curved, J, and progressive line arrays. In addition, expressions are provided to analyze the effects of curved radiating sources and gaps between sources in line arrays. Several examples are provided to compare estimated performance against measured data. Fast Convolution Technique Using a Nonuniform Sampling Scheme: Algorithm and Applications in Audio Signal Processing...... Mingsian R. Bai and Pingshun Zeung 496 Using a nonuniform sampling, a fast convolution algorithm greatly reduces the complexity and increases the computational efficiency by providing high resolution at low frequencies and low resolution at high frequencies. Examples of a head-related transfer function and a reverberant room response illustrate good subjective performance even though the results are distinguishable from direct convolution. This approach exploits the differences in spectral resolution for human hearing.

ENGINEERING REPORTS Measurement of Reverberation Times Using a Wavelet Filter Bank and Application to a Passenger Car ...... Sang-Kwon Lee 506 Measuring the reverberation time in small spaces using traditional methods is difficult because the product of the bandwidth and reverberation time is too small. A wavelet transform method using a wavelet filter bank has been successfully used to measure the reverberation time of the passenger compartment of an automobile, where such times were on the order of 0.05 seconds. Synthetic impulse responses from a toy balloon were used as an impulse response for exciting the space. Wavetable Matching of Pitched Inharmonic Instrument Tones...... Clifford So and Andrew B. Horner 516 By relaxing the normal assumption of harmonic tones in wavetable synthesis, a new approach allows for using wavetables for plucked instruments, such as the Chinese qin and yangqin. The new method uses a hierarchical grouping of the original tone’s partials based on their normalized frequency deviation. Using a fully automatic operation, the results show slight improvement on the perceived match with harmonic tones and a greatly improved match on pitched inharmonic tones.

LETTERS TO THE EDITOR Dipole, Monopole, or Near-Field Woofer—Physics and Perception...... Tomas Salava 530 Author’s Reply...... Siefried Linkwitz 532 Comments on “Why Is Bass Reproduction from a Dipole Woofer in a Living Room Often Subjectively More Accurate Than from a Monopole Woofer?” ...... Frank Fahy 532

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 533 Standards in Action: AES47 professional audio networking

FEATURES Wavefield Synthesis: Evolution from Stereophony and Some Practical Challenges ...... 538 117th Convention, San Francisco, Call for Workshop Participants...... 569

DEPARTMENTS Review of Acoustical Patents...... 535 Membership Information...... 556 News of the Sections...... 544 Advertiser Internet Directory...... 557 Sound Track ...... 550 In Memoriam ...... 567 New Products and Developments...... 552 Sections Contacts Directory ...... 570 Upcoming Meetings ...... 554 AES Conventions and Conferences ...... 576 Available Literature...... 554 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 52 NUMBER 6 2004 JUNE CONTENT PAPERS Efficient Generation of Multichannel Dither Signals...... Robert A. Wannamaker 579 When a dither source is needed for multichannel quantization, efficient techniques reduce the computational burden of computing each channel independently. By using appropriate matrix transformations, a single rectangular probability density function (RPDF) random number per sample per channel can be used to produce independent identically distributed (iid) triangular probability density function (TPDF) dither for each channel. After quantization, the errors in each channel are uncorrelated with one another and each has an input-independent mean and variance. Time-Quantized Frequency Modulation, Time-Domain Dither, Dispersive Codes and Parametrically Controlled Noise Shaping in SDM...... M. O. J. Hawksford 587 Comparing sigma–delta modulator (SDM) performance to a mathematically equivalent coding technique based on linear frequency modulation (LFM) and time-domain quantization provides additional insight into the noise behavior of SDM. Normally if the conclusions drawn from studies of linear quantization and triangular dither are applied to SDM, then the two-level quantizer range is violated and instability results. Nevertheless, the chaotic-like loop behavior of high-order SDM even with apparent suboptimal dither demonstrates low correlation distortion and is shown here to be insensitive to dither statistics. The LFM model applies dither in the time domain rather than the amplitude domain and does not violate these assumptions. Augmented Reality Audio for Mobile and Wearable Appliances ...Aki Härmä, Julia Jakka, Miikka Tikander, Matti Karjalainen, Tapio Lokki, Jarmo Hiipakka, and Gaëtan Lorho 618 In a portable device, integrating environmental sounds with synthetically generated audio leads to the concept of a wearable device that produces augmented reality. Listeners wear a headset configuration that includes a binaural microphone and stereophonic headphones. In addition to feeding sounds of the environment to the headphones, an auxiliary input provides the means for reproducing recorded audio in a virtual space. Listening tests with a prototype system showed that some experienced listeners found it difficult to distinguish between real and virtual sources. Room Sizing and Optimization at Low Frequencies ...... Trevor J. Cox, Peter D’Antonio, and Mark R. Avis 640 In critical listening environments, the modes in a room of low volume produce an uneven frequency response and extended decay rates at low frequencies. Using a cost metric based on minimizing the deviations from the flattest possible modal response, the authors propose a new method for choosing the appropriate dimensions for a room of a given volume. While there is a numerically optimum solution, many local minima are equivalent in terms of quality, which then allows for incorporating the physical constraints of real buildings. LETTERS TO THE EDITOR Comments on “Wavefront Sculpture Technology”...... Chao Jiang and Yong Shen 652 Authors’ Reply...... M. Urban, C. Heil, and P. Bauman 653 CORRECTIONS Correction to “Graphing, Interpretation, and Comparison of Results of Loudspeaker Nonlinear Distortion Measurements”...... A. Voishvillo, A. Terekhov, E. Czerwinski, and S. Alexandrov 655 Correction to “Historical Perspectives and Technology Overview of Loudspeakers for Sound Reinforcement”...... J. Eargle and M. Gander 655 STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 656 Audio measurements; metadata FEATURES How Loud Is My Broadcast?...... 662 DEPARTMENTS Review of Acoustical Patents...... 659 Membership Information...... 679 News of the Sections...... 670 Advertiser Internet Directory...... 689 Upcoming Meetings ...... 673 In Memoriam ...... 689 Sound Track ...... 675 Sections Contacts Directory ...... 690 New Products and Developments...... 676 AES Conventions and Conferences ...... 696 Available Literature...... 678 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 52 NUMBER 7/8 2004 JULY/AUGUST

CONTENT PAPERS Predicting the Perceived Quality of Nonlinearly Distorted Music and Speech Signals ...... Chin-Tuan Tan, Brian C. J. Moore, Nick Zacharov, and Ville-Veikko Mattila 699 An analytical model predicts the perceived quality of speech and music when subjected to various forms of nonlinear distortion, thus providing the ability to evaluate audio transducers and transmission systems. The model incorporates the filtering produced by the auditory system so that the perceptual consequences of spurious spectral components are correctly evaluated. By cross-correlating each spectral bin of the input and output signals, the measure of distortion, called Rnonlin, accurately predicts the subjective ratings of listeners. This approach improves on the earlier metric, called Distortion Score, which was less accurate for real transducers. Multi-Actuator Panels (MAPs) as Loudspeaker Arrays for Wave Field Synthesis .....Marinus M. Boone 712 Distributed mode loudspeakers become suitable for wave field synthesis when multiple exciters are embedded in a single panel. In contrast, a large number of loudspeaker panels is not efficient and has low-frequency limitations. As long as the initial part of the impulse response of individual drivers is phase consistent, deviations from an ideal response can be corrected with filtering. Increasing the internal damping by applying a foam board panel was sufficient to achieve accurate wave front curvature as would be obtained from real sources. Multi-actuator panel arrays of loudspeakers are lightweight and thin and can be readily mounted on wall surfaces. Hierarchical Automatic Audio Signal Classification ...... Juan José Burred and Alexander Lerch 724 The advantages and disadvantages of using a hierarchical system for analyzing and classifying audio file content are explored. Such systems are analogous to content analysis for text material. In the hierarchical approach, top-level tree decisions, such as distinguishing between speech and music, approach 95% accuracy, while the more subtle distinctions lower in the tree, such as genres of chamber music, remain at a modest 50%. The authors provide an extensive review of the state of the art in order to place their research into perspective.

ENGINEERING REPORTS A Frequency-Domain Approach to Multichannel Upmix ...... Carlos Avendano and Jean-Marc Jot 740 Because of the wide availability of mulitchannel reproduction equipment and the limited availability of music recorded for formats other than stereo, upmixing a two-channel recording into multichannel format (for example 5.1) would be very useful. By comparing the two stereo channels, it is possible to identify and unmix amplitude-panned sources and to identify and extract background spatial ambience. This allows the redistribution of spatial information and the creation of additional channels to be rendered by the multichannel equipment. The algorithm is based on analyzing the two channels in the time–frequency domain and then observing the degree of similarity and correlation between them.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 750 Digital audio connectors; synchronization; transfer technologies; listening tests; shielding; file interchange; Internet audio

FEATURES 116th Convention Report, Berlin...... 756 Exhibitors ...... 772 Program...... 776 117th Convention Preview, San Francisco...... 828 Exhibitors ...... 831 Exhibit Previews ...... 835 Education News...... 860

DEPARTMENTS News of the Sections...... 862 Membership Information...... 868 Sound Track ...... 866 Advertiser Internet Directory...... 871 Available Literature...... 867 Sections Contacts Directory ...... 873 Upcoming Meetings ...... 868 AES Conventions and Conferences ...... 880 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 52 NUMBER 9 2004 SEPTEMBER

CONTENT

PAPERS Errors in Real-Time Room Acoustics Dereverberation ...... Panagiotis D. Hatziantoniou and John N. Mourjopoulos 883 While researchers have been studying methods for removing the effects of room acoustics for over 20 years, results are often inconsistent between computer simulations and real applications. This discrepancy has not been formally studied. Errors in measurements of real spaces are significantly higher than expected, even when they are carefully performed. Additionally, when combined with long filters, perceptual artifacts are often worse than the advantages of such systems. High-Q poles used in such filters are very sensitive to listener location and to time-varying acoustic noise present inside the room. By using complex smoothing, which implies a reduction in the degree of room compensation, unpleasant artifacts are greatly reduced. Development and Validation of a Method for Predicting the Perceived Naturalness of Sounds Subjected to Spectral Distortion ...... Brian C. J. Moore and Chin-Tuan Tan 900 Having partitioned distortion into linear and nonlinear distortion and having explored the degree to which such distortions degrade the perception of naturalness, the authors now propose a model to explain the perceptual effects of linear distortion, namely, irregularities in the frequency response. Using the data from 168 filtering conditions, a perceptual model based on excitation patterns has been developed to predict subjective judgments. The model is based on the difference between the excitation patterns for undistorted and distorted pink noise. Two validation experiments supported the model. Interpositional Transfer Function for 3D-Sound Generation ...... F. P. Freeland, L. W. P. Biscainho, and P. S. R. Diniz 915 In order for head-related transfer functions to gain widespread use in binaural audio applications, there needs to be efficient ways for interpolating among a limited number of reference cases that are quantized in elevation and azimuth without loss of perceived accuracy. A triangular interpolation combined with an auxiliary function, called interpositional transfer function, save more than 40% of the operations required by the traditional bilinear methods. This method was employed in a system that generated moving locations. Measurement and Application of Equivalent Input Distortion ...... Wolfgang Klippel 931 Because a loudspeaker can be considered as a single-input, multiple-output transducer, distortion should ideally be measured at multiple spatial locations. This produces a massive collection of data, much of which is redundant. Rather, the author shows that the dominant nonlinearities add distortion to the input signal, which is transferred by a linear system to each point in space. This model leads to a new measurement technique that gives deeper insight into the distortion mechanisms and the influence of the acoustical environment, noise, and parasitic vibrations.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 948 Digital audio measurement; storage and handling; digital library and archive systems; acoustics—sound source modeling; loudspeaker measurement; IEEE 1394; audio metadata

FEATURES 25th Conference Report, London...... 952 Bass Handling in Spatial Reproduction ...... 962 118th Convention, Barcelona, Call for Papers ...... 991

DEPARTMENTS News of the Sections...... 968 Membership Information...... 981 Sound Track ...... 977 Advertiser Internet Directory...... 982 Upcoming Meetings ...... 978 Sections Contacts Directory ...... 993 New Products and Developments...... 979 AES Conventions and Conferences ...... 1000 Available Literature...... 980 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 52 NUMBER 10 2004 OCTOBER

CONTENT

PAPERS Subjective Investigations of Inverse Filtering ...... Scott G. Norcross, Gilbert A. Soulodre, and Michel C. Lavoie 1003 Much of the research on inverse filtering to correct room or loudspeaker irregularities assumes (without confirmation) that such techniques will improve the subjective listening experience. When this assumption is carefully tested, surprisingly, many techniques actually degrade overall audio quality rather than improve it. Two kinds of inverse filtering were tested: time-domain least squares and frequency deconvolution. Some additional techniques avoided perceptual artifacts but with an inconsistent amount of improvement. Analysis of a Folded Acoustic Horn...... Andrew Bright, Keith Holland, and Frank J. Fahy 1029 Advanced analysis techniques, such as the boundary-element method (BEM), show that a folded horn can be represented by a one-parameter model at low frequencies. Such a model is able to reproduce the throat and transfer impedances as well as the pressure response with high accuracy below 300 Hz. At higher frequencies a more complex model is required. Although the BEM method can contribute to understanding low-frequency folded horns, it remains a complex analysis technique requiring specialized skills. The Distributed Edge Dipole (DED) Model for Cabinet Diffraction Effects ...... M. Urban, C. Heil, C. Pignon, C. Combet, and P. Bauman 1043 A simple model, called distributed edge dipole, is proposed to explain the effects of cabinet edge diffraction on the radiated sound from a direct-radiating loudspeaker when mounted in an enclosure. In comparison to two other techniques, the proposed model more accurately predicts measurements of a thin circular baffle over 50 to 1000 Hz and over a wide angular range from 0 to180 degrees. More specifically, the improvements were obtained in the boundary region between the forward and backward directions.

COMMUNICATIONS Subjective Loudspeaker Testing for Accuracy ...... David Lloyd ben Yaacov Yehuda Klepper 1060 Discussions about subjective loudspeaker preferences often ignore the need for a rating scale to evaluate accuracy. Preferences and accuracy are different perceptual qualities. Accuracy relates to the degree to which a reproduced sound field is subjectively equivalent to a corresponding live presentation of the same source. There is no proof that preferences among different individuals will match accuracy.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 1065 Microphone measurement

FEATURES A Symposium on Multichannel Audio for Radio Broadcasters...... 1066 Review of Society’s Sustaining Members ...... 1072 118th Convention, Barcelona, Call for Papers ...... 1111 26th Conference, Denver, Call for Papers ...... 1112

DEPARTMENTS Reviews of Acoustical Patents...... 1062 Available Literature...... 1102 News of the Sections...... 1094 Membership Information...... 1103 Upcoming Meetings ...... 1097 In Memoriam ...... 1110 Advertiser Internet Directory...... 1097 Sections Contacts Directory ...... 1113 Sound Track ...... 1098 AES Conventions and Conferences ...... 1120 New Products and Developments...... 1100 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 52 NUMBER 11 2004 NOVEMBER CONTENT President’s Message...... Theresa Leonard 1123 PAPERS Dithered Noise Shapers and Recursive Digital Filters ...... Stanley P. Lipshitz, Robert A. Wannamaker, and John Vanderkooy 1124 Quantizers combining the use of colored, nonsubtractive dither with or without noise-shaping error feedback are closely examined for the first time. In particular, it is shown that the appropriate use of spectrally shaped dither signals entails subtle practical and theoretical considerations, especially if such dithers are combined with noise-shaping schemes. A rigorous analysis of systems employing such dither signals with and without feedback is undertaken, yielding practical guidelines that ensure satisfactory results in applications. In particular, it is shown that the class of dither signals suitable for combination with noise shaping is greatly restricted. Motion-Tracked Binaural Sound...... V. Ralph Algazi, Richard O. Duda, and Dennis M. Thompson 1142 By using a head tracking system that selects from an array of microphones placed on a surface that approximates the listener’s head, the authors have created an alternative to the conventional binaural recording technique. Based on the orientation of the listener, the appropriate microphone is selected or the signals from a pair of microphone signals are interpolated. Head tracking provides strong dynamic cues that create a strong sense of realism with a reduced need for pinna matching. This approach supports multiple listeners from a single microphone array. Importance and Representation of Phase in the Sinusoidal Model ...... Tue Haste Andersen and Kristoffer Jensen 1157 While the importance of differential phase among the components of an audio signal has been debated over the years, experiments show that both synthesized and encoded audio need to consider phase integrity. Subjective listening tests with sounds that were synthesized with varying amounts of phase information clearly demonstrate the need to use a reliable phase model, especially with common harmonic musical sounds. A novel phase representation, called partial-period phase, characterizes phase evolution as an almost stationary parameter. ENGINEERING REPORTS Direct Approximate Third-Order Response Synthesis of Vented-Box Loudspeaker Systems ...... Bernat Llamazares 1170 Extending the earlier work on vented-box loudspeaker systems, a new approach is proposed that provides approximate third-order frequency-response alignments characterized by featuring a good transient response at reduced efficiency for the lower frequencies. These new alignments are very suitable for low-resonance, low-Q drivers, producing a response characteristic midway between a second-order sealed-box and a fourth-order vented-box loudspeaker system. This approach provides an additional degree of freedom in the design. CORRECTIONS Correction to “Analysis of Loudspeaker Line Arrays” ...... Mark S. Ureda 1176 STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 1177 Synchronization; optical disks; media storage; file interchange; jitter FEATURES Metadata Revisited: Six New Things to Know About Audio Metadata ...... 1178 Digital Archive Strategies and Solutions for Radio Broadcasting...... 1180 New Officers 2004/2005...... 1185 26th Conference, Denver, Call for Papers ...... 1200 DEPARTMENTS News of the Sections...... 1188 Membership Information...... 1195 Upcoming Meetings ...... 1192 Advertiser Internet Directory...... 1197 Sound Track ...... 1192 Sections Contacts Directory ...... 1201 New Products and Developments...... 1193 AES Conventions and Conferences ...... 1208 Available Literature...... 1194 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 52 NUMBER 12 2004 DECEMBER CONTENT PAPERS Subtractive and Nonsubstractive Dithering: A Mathematical Comparison ...Robert A. Wannamaker 1211 The relative advantages and disadvantages of subtractive and nonsubtractive dithering are explored from a mathematical perspective. Subtractively dithered systems can yield quantization errors that are statistically independent of the input signal, but that require the dither signal be either transmitted or reconstructed at the receiver. In contrast, nonsubtractively dithered systems avoid this drawback but increase the level of noise at the output and can only render a specified number of statistical error moments independent of the system input. Nonetheless, appropriately chosen nonsubtractive dither signals prove suitable for audio and many other applications. The treatment presented extends to include new results regarding the use of spectrally colored dither signals in systems with and without noise-shaping error feedback. Measuring and Predicting the Perceived Quality of Music and Speech Subjected to Combined Linear and Nonlinear Distortion ...... Brian C. J. Moore, Chin-Tuan Tan, Nick Zacharov, and Ville-Veikko Mattila 1228 A new model is presented for predicting the perceived quality of audio signals subjected to both linear and nonlinear distortion. Earlier research produced metrics for predicting the effects of linear distortion (frequency response irregularity) and nonlinear distortion (production of spurious spectral components). The new model, which includes both metrics, provides predictions that correlate highly with results of subjective tests: correlations were 0.90 for music and 0.85 for speech. Circular Recital Hall Design Considering Source Directivity ...... Wei-Hwa Chiang, Yi-Nuo Chao, Jow-Yeh Lee, and Hui-Ping Wu 1245 During the remodeling of the Carrie Chang Music Hall, early reflections were incorporated into the acoustical design in order to compensate for the loss of high frequencies in those seats that were off axis. The design concentrated on several issues: changes in tone quality resulting from source directivity, sound focusing from curved surfaces, and coloration due to discrete early reflections. Computer and scale models allowed for acoustic analysis during successive design phases. ENGINEERING REPORTS Study of the Directional Characteristics of a Piston Mounted on a Surface of Zero Acoustic Impedance ...... José Luis Barros, Jorge Cárdenas, and Jorge Sommerhoff 1254 The surface impedance of a loudspeaker baffle strongly influences the directionality of the radiation pattern. By contrasting the radiation pattern of a vibrating piston mounted in a surface having infinite impedance with one having zero impedance, the importance of surface impedance is clearly demonstrated. Because energy cannot flow horizontally in a zero impedance surface, energy is concentrated in the axial direction. A two-dimensional model produced results that were consistent with those measured in the laboratory. LETTERS TO THE EDITOR Comments on “Coding for High-Resolution Audio Systems” ...... David Moran, Roy Allison, and E. Brad Meyer 1259 ...... David Hadaway 1259 Author’s Reply ...... J. Robert Stuart 1259 STANDARDS AND INFORMATION DOCUMENTS Special Feature: Real-World Applications of ATM Networking for Professional Audio Using the AES47 Standard...... David Errock 1265 FEATURES The World of Digital Radio...... 1272 Call for Nominations for Board of Governors ...... 1290 Call for Awards Nominations...... 1291 12th Regional Convention, Tokyo, Call for Papers ...... 1299 27th Conference, Copenhagen, Call for Papers...... 1300 Bylaws: Audio Engineering Society, Inc...... 1301 Index to Volume 52 ...... 1305 DEPARTMENTS Reviews of Acoustical Patents...... 1262 Membership Information...... 1292 News of the Sections...... 1280 Advertiser Internet Directory...... 1296 Sound Track ...... 1286 In Memoriam ...... 1297 New Products and Developments...... 1287 Sections Contacts Directory ...... 1321 Available Literature...... 1289 AES Conventions and Conferences ...... 1328 Upcoming Meetings ...... 1289 p2_TOCJan 1/3/05 10:16 AM Page 1

JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 53 NUMBER 1/2 2005 JANUARY/FEBRUARY CONTENT New Editor of the Journal ...... Theresa Leonard 3 PAPERS Development and Initial Validation of a Multichannel Audio Quality Expert System ...... S⁄lawomir Zielinski,´ Francis Rumsey, Rafael Kassier, and Søren Bech 4 When a fixed channel bandwidth must be allocated among different types of services, such as sound, picture, and data, the audio engineer must arbitrate among conflicting demands on bandwidth. Is it better to have a lesser number of high-quality channels or more channels of lower quality? This research creates a predictive measure of graceful degradation with limited audio channel capacity. Subjective tests confirm that the proposed objective metrics predict audio quality as a function of channel bandwidth, as a function of down-mix algorithm, and as a combination of both. A New Cognitive Model of Objective Assessment of Audio Quality ...... Jayme Garcia Arnal Barbedo and Amauri Lopes 22 The objective measures provided by the current ITU Perceptual Evaluation of Audio Quality psychoacoustic standard fail to match the subjective experience under many conditions. An alternative model based on a cognitive model improves the correlation between subjective and objective measures. The new model extracts a set of parameters from the audio signal, which are then mapped into a single metric to predict subjective quality. Six cognitive parameters are extracted from a filter-bank model. ENGINEERING REPORTS Multiple Piano Note Identification Using a Spectral Matching Method with Derived Patterns ...... L. I. Ortiz-Berenguer, F. J. Casajús-Quirós, and S. Torres-Guijarro 32 Detecting the component notes in a chord depends upon the particular musical instrument. By restricting the research to piano chords, and by using a spectral pattern-matching technique, the proposed approach successfully identifies up to four components of the chord. Chords are analyzed note by note, iteratively removing the contribution of each once identified. Spectral patterns of notes, derived from an acoustic model of a piano, were determined during a training session. Auditory Evacuation Beacons ...... Sander J. van Wijngaarden, Adelbert W. Bronkhorst, and Louis C. Boer 44 Conventional auditory beacons, emergency sounds that guide people to a safe exit when vision is obscured by smoke, use modulated noise. But such signals also require explicit verbal instructions in order to navigate to an exit. A new signal was designed as a combination of a chime sound with a spoken message. In a tunnel environment without prior instructions to the participants, the evacuation success rate was 16% for conventional beacons and 87% for the newly designed beacons. Furthermore, by exploiting the precedence effect through the application of time delays, 88% of the participants were able to follow the sound to its location in a simulated ship’s interior. STANDARDS AND INFORMATION DOCUMENTS Standards in print; digital audio connectors; calls for comment on shielding and MADI; reorganization of SC-06; digital audio measurement; input/output interfacing; audio file transfer...... 54

FEATURES 117th Convention Report, San Francisco ...... 58 Exhibitors ...... 74 Program...... 79 The Software Studio in the Age of Audio Networking ...... 124 Some Thoughts on the Dynamics of Reproduced Sound...... Neville Thiele 130 Education News...... 133 12th Regional Convention, Tokyo, Call for Papers ...... 150 27th Conference, Copenhagen, Call for Papers...... 151 119th Convention, New York, Call for Papers ...... 152 DEPARTMENTS News of the Sections...... 135 Membership Information...... 143 Upcoming Meetings ...... 139 Advertiser Internet Directory...... 147 Sound Track ...... 140 In Memoriam ...... 149 New Products and Developments...... 141 Sections Contacts Directory ...... 153 Available Literature...... 142 AES Conventions and Conferences ...... 160 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 53 NUMBER 3 2005 MARCH

CONTENT

PAPERS Vertical Localization of Sound from Multiway Loudspeakers ...... Sam Ferguson and Densil Cabrera 163 While most loudspeaker designers are concerned with localization in the horizontal plane, perceived vertical location usually does not receive sufficient attention. When synchronous and asynchronous noise bands at high and low frequencies are presented, the vertical locations of each signal are not necessarily aligned. Moreover, the location of the high-frequency band tends to dominate the location of the low-frequency band when both are simultaneously present.

Comparison of Basic Audio Quality and Timbral and Spatial Fidelity Changes Caused by Limitation of Bandwidth and by Down-Mix Algorithms in 5.1 Surround Audio Systems ...... S⁄lawomir K. Zielinski,´ Francis Rumsey, Rafael Kassier, and Søren Bech 174 When there is inadequate channel bandwidth to transmit full high-quality audio in multiple surround channels, spatial fidelity should be sacrificed. Mixing down multiple channels to a smaller number is preferred over limiting the bandwidth of all channels. Timbral quality is a more important contributor to basic audio quality than spatial quality in the context of modern systems. Intercomparison Measurements of Room Acoustical Parameters and Measures for Speech Intelligibility in a Room with a Sound System ...... Kurt Eggenschwiler and Rainer Machner 193 The qualitative control of specifications for sound systems and rooms is becoming more and more important. But what is the uncertainty of the related acoustics measurements? Intercomparison measurements showed that the standard deviations were often within the region of the perception thresholds. Achieving consistent results may depend on such factors as better training of acousticians.

COMMUNICATIONS Wavetable Synthesis Strategies for Mobile Devices ...... Robert C. Maher 205 Unlike the design choices made for wavetable synthesis of music, strategies for customized ring tones in cell phones and pagers require a different optimization. In this application: higher levels of compression are needed; memory storage is limited; and compute power is sparse. However, by careful selection of the sample set and its representation during encoding, a new strategy achieves 12-bit performance with up to 50% compression.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 214 Audio over IEEE 1394; Internet audio quality; analog recording; transfer technologies; storage and handling of media; digital library and archive systems; forensic audio; sound source modeling; loudspeaker measurement; grounding and EMC practices

FEATURES 118th Convention Preview, Barcelona...... 218 List of Exhibitors and Previews ...... 220 New Developments in Low Bit-Rate Coding ...... 235 119th Convention, New York, Call for Papers ...... 263

DEPARTMENTS News of the Sections...... 242 Advertiser Internet Directory...... 251 Upcoming Meetings ...... 245 In Memoriam ...... 261 Sound Track ...... 246 AES Annual Report ...... 264 Available Literature...... 249 Sections Contacts Directory ...... 265 Membership Information...... 250 AES Conventions and Conferences ...... 272 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 53 NUMBER 4 2005 APRIL

CONTENT

PAPERS System Measurement and Identification Using Pseudorandom Filtered Noise and Music Sequences...... M. O. J. Hawksford 275 Either music sequences or pseudorandom filtered noise can be used to evaluate simultaneously the transfer function and distortion mechanisms in audio systems. This approach is applicable to amplifiers, signal processors, digital-to-analog converters, loudspeakers, and perceptual coders. In addition, the technique allows nonlinear modeling using a simplified Volterra model. Because the technique is a single-pass analysis, the effect of time-varying changes is minimized.

Synthesis of Room Responses Using Virtual Source Representation with Application in Reverberator Design...... Mingsian R. Bai and Kwuen-Yieng Ou 297 Conventional methods for synthesizing reverberation and a spatial impression consider the space separately from the sound source. In the proposed method the sound field is represented by a mesh of virtual sources at the boundary surface, rather than by a simple image method or ray-tracing procedure. Physical settings of the space are naturally incorporated into the model. Numerical simulations were performed for a rectangular room and a concert hall, and subjective listening tests confirmed that the technique is capable of rendering remarkable realism. Only the early part of the reverberation process is represented in this approach.

Direct-Radiator Loudspeaker Efficiency at Fundamental Resonance ...... Carlo Zuccatti 307 For direct-radiator loudspeakers, the efficiency at resonance is often higher than the rated efficiency at midfrequencies, which are assumed to be the more useful frequency range. Band-limited systems, such as subwoofer enclosures using loudspeakers operating near their resonant frequency, can take advantage of this effect, especially with low DC resistance voice coils.

ENGINEERING REPORTS A Comparison between Local Search and Genetic Algorithm Methods for Wavetable Matching ...... Simon Wun and Andrew Horner 314 The effectiveness and efficiency of wavetable synthesis of musical notes require a strategy for selecting the basis spectra from which the notes can be synthesized. This work describes a local search method for basis spectra that improves the performance with simple selection criteria. Five methods converged to within an error range of about 1%, though occasionally the algorithm gets stuck on defective local optimum.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 326 MADI guidelines; recorded fluxivity; magnetic tape handling; microphone measurements and digital interface

FEATURES Multichannel Audio Systems and Techniques...... 329 Shake, Rattle, and Roll; Getting Immersed in Multisensory, Interactive Music via Broadband Networks ...... Wieslaw Woszczyk, Jeremy Cooperstock, John Roston, and William Martens 336

DEPARTMENTS Upcoming Meetings ...... 344 Membership Information...... 355 News of the Sections...... 345 In Memoriam ...... 360 Sound Track ...... 348 Sections Contacts Directory ...... 361 New Products and Developments...... 350 AES Conventions and Conferences ...... 368 Available Literature...... 352 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 53 NUMBER 5 2005 MAY

CONTENTS

PAPERS Effect of Noise and Transducer Variability on the Performance of Circular Microphone Arrays ...... M. A. Poletti 371 As a low-cost alternative for three-dimensional microphone arrays, circular arrays are appropriate for analyzing room acoustics, recording live sound fields, and providing teleconferencing applications. The ideal performance of such arrays is limited by additive noise and transducer variability. These two effects are quantitatively examined for the simple case of incident plane waves. The effective signal-to-noise ratio depends on the frequency, the area of the array, and the density of microphones. Variations in phase among microphones produce high-order polar response errors at low frequencies.

The Active Listening Room: A Novel Approach to Early Reflection Manipulation in Critical Listening Rooms ...... Amber Naqvi and Francis Rumsey 385 Rather than trying to change the natural acoustics of a space, adding active panels and loudspeakers creates an active listening area within an existing space. Simulations using a computer-based acoustic design package determine the required parameters for creating the target space. This approach is more flexible than standardized reference listening rooms. In effect, the acoustics of a small region within a large space is being controlled.

Audible Noise Suppression with a Real-Time Broad-Band and Superdirective Microphone Array ...... Jose-Luis Sanchez-Bote, Joaquin Gonzalez-Rodriguez, and Javier Ortega-Garcia 403 By extending algorithms used for noise suppression from a single microphone to a 15-microphone nested linear array, extra spatial information then contributes additional noise reduction. This extra information is better able to improve the clean speech signal estimates, and hence to make better decisions about in which spectral regions the noise is masked. The system has been evaluated off-line and in highly reverberant spaces under different noise conditions. The performance of superdirective beams can thus be improved.

ENGINEERING REPORTS Low-DC-Resistance, Low-Frequency Loudspeaker Enclosures ...... Carlo Zuccatti 419 By using loudspeaker drives with low voice-coil resistance, the sensitivity near resonance can be significantly increased. However at frequencies far from resonances, an additional passive filter provides safe impedance to the amplifier. The combination improves the sensitivity and power output in low-frequency enclosures. This approach has an extra degree of freedom not normally found with such enclosures.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 429 Shielding; high-resolution multichannel audio interconnection (HRMAI); metadata

FEATURES 26th Conference Preview, Denver ...... 434 Calendar ...... 436 Program...... 438 Registration Form...... 442 Measuring and Predicting Perceived Audio Quality...... 443

DEPARTMENTS

Reviews of Acoustical Patents...... 432 Available Literature...... 457 News of the Sections...... 449 Membership Information...... 459 Upcoming Meetings ...... 454 Advertiser Internet Directory...... 461 Sound Track ...... 455 Sections Contacts Directory ...... 465 New Products and Developments...... 456 AES Conventions and Conferences ...... 472 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 53 NUMBER 6 2005 JUNE CONTENTS PAPERS Low Peak Amplitudes for Group Additive Synthesis ...... Andrew Horner and Simon Wun 475 Optimizing wavetable synthesis for maximum signal-to-noise ratio should take advantage of manipulating the phase of the components in order to reduce the peak amplitude for a given spectrum. This paper compares various phase selection methods on group additive synthesis, a special case of multiple wavetable synthesis, where each wavetable contains a distinct subset of the harmonics. Group additive synthesis peak factors are up to 30% worse than their counterparts, unless wavetable matching and peak-factor optimization are integrated. The genetic algorithm and simulated annealing methods get the best performance out of both multiple wavetable synthesis and group additive synthesis.

ENGINEERING REPORTS Reconstruction of Recorded Sound from an Edison Cylinder Using Three-Dimensional Noncontact Optical Surface Metrology ...... Vitaliy Fadeyev, Carl Haber, Christian Maul, John W. McBride, and Mitchell Golden 485 Audio information stored in the undulations of a groove in a mechanical sound carrier, such as a cylinder or disk phonograph record, may be reconstructed, without contact, by measuring the groove shape and position using precision optical metrology methods and digital image processing. This report describes the first three- dimensional reconstruction of recorded sound from a mechanical carrier using this approach. The source material, a celluloid Edison cylinder, was scanned using color-coded confocal microscopy techniques. The results and prospects of this approach are discussed. Large-Signal Analysis of Class A Vacuum Triode Push–Pull Output Stage ...... Muhammad Taher Abuelma'atti 509 A mathematical model of the transfer function of class A push–pull triode amplifiers yields closed-form series expressions for the amplitudes of output spectral components. The results are similar to those of a transistor class A output stage, containing odd-order harmonics and intermodulation components. For small amplitude signals, the degrading components are very small; they monotonically increase with large input tones. The parameters of the model can readily be determined using simple calculations. Servo Control of Loudspeaker Cone Motion Using an Optical Linear Displacement Sensor ...... W. Geiger 518 Large signals in a loudspeaker produce distortion because of nonlinear force factors and changing stiffness. Both effects can be reduced by a classical feedback loop that uses optical means to sense the displacement and cone motion. By sensing the actual location of the cone structure, feedback linearizes the system without requiring a detailed model to precompensate for nonideal mechanical properties. In addition, the feedback system can improve the magnitude and phase versus frequency.

LETTERS TO THE EDITOR Comments on “Analysis of a Folded Acoustic Horn” ...... Earl Geddes 525 Authors’ Reply ...... Andrew Bright, Keith Holland, and Frank J. Fahy 526

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 528 Care and handling of magnetic tape; overview of AES standards

FEATURES 27th Conference Preview, Copenhagen ...... 532 Calendar ...... 534 Program...... 536 Registration Form...... 540 Automotive Audio Quality...... 542

DEPARTMENTS News of the Sections...... 549 Membership Information...... 561 Upcoming Meetings ...... 554 Advertiser Internet Directory...... 563 Sound Track ...... 555 In Memoriam ...... 568 New Products and Developments...... 557 Sections Contacts Directory ...... 569 Available Literature...... 558 AES Conventions and Conferences ...... 576 p.578_TOC 8/2/05 3:15 PM Page 1

JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 53 NUMBER 7/8 2005 JULY/AUGUST CONTENTS PAPERS High-Efficiency Low-Bl Loudspeakers ...... Ronald M. Aarts 579 As a critical design parameter of loudspeakers, especially at low frequencies, the force factor (Bl) determines the efficiency, impedance, sound level, temporal response, weight, and cost. High-Bl drivers have good efficiency but require large magnet systems. An alternative approach, which yields much lower cost and weight while preserving efficiency, uses low-Bl drivers. Prototype drivers with moving magnets and stationary coils were evaluated in a limited frequency range where efficiency is highest. This approach is suited to small portable loudspeakers. Discrimination of Group Delay in Clicklike Signals Presented via Headphones and Loudspeakers ...... Sheila Flanagan, Brian C. J. Moore, and Michael A. Stone 593 The threshold for detecting a frequency-dependent group delay in a clicklike sound was found to be independent of the center frequency of the delay (1-4 kHz) and was about 2 ms for presentation via headphones, or via loudspeakers in a nonreverberant room, for both binaural and monaural listening. In a reverberant room, thresholds increased, especially at low frequencies. These results suggest that the nonlinear phase response of loudspeakers is unlikely to have any audible effect in typical rooms. A Simple Hybrid Approach to the Time-Scale Modification of Speech ...... Don Knox, Nicholas Bailey, and Iain Stewart 612 Time-domain methods for stretching speech usually produce stuttering and roughness artifacts from mismatches at signal segment boundaries, especially with time-stretch ratios greater than 1.3. By combining time-domain and analysis-synthesis methods, a simple hybrid approach greatly reduced such artifacts at ratios greater than 1.6. Formal listening tests demonstrate an improvement in speech quality without incurring the complexity burden of full analysis-synthesis methods. The hybrid algorithm counters spectral mismatch and transient repetition. ENGINEERING REPORTS Directivity of Artificial and Human Speech ...... Teemu Halkorsaari, Markus Vaalgamaa, and Matti Karjalainen 620 Having an artificial mouth with the same radiating characteristics of real speakers provides a useful working tool for telecommunications research. Responses to three mouth simulators were compared to that of a group of test subjects in order to evaluate their similarity. More than 10 dB of difference was discovered in the two cases. The main contributors to the human radiating characteristics are mouth aperture size and effects of the upper body. LETTERS TO THE EDITOR Comments on “Low-DC-Resistance, Low-Frequency Loudspeaker Enclosures”.....Alex de Koster 632 Author’s Reply ...... Carlo Zuccatti 632 CORRECTIONS Correction to “Low-DC-Resistance, Low-Frequency Loudspeaker Enclosures” ...... Carlo Zuccatti 632 STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 633 High-resolution multichannel digital interface (HRMAI); digital measurements; digital interfacing; file transfer; transfer technologies; microphones; listening tests FEATURES 118th Convention Report, Barcelona...... 642 Exhibitors ...... 658 Program...... 661 119th Convention Preview, New York ...... 714 Exhibit Previews ...... 716 High-Density Optical-Disk Formats ...... 749 High-Resolution Audio in an Age of Universal Playback...... 754 DEPARTMENTS Reviews of Acoustical Patents...... 636 Membership Information...... 765 News of the Sections...... 756 Advertiser Internet Directory...... 767 Sound Track ...... 762 In Memoriam ...... 775 Upcoming Meetings ...... 763 Sections Contacts Directory ...... 777 Available Literature...... 763 AES Conventions and Conferences ...... 784 p.786_TOCpat 8/31/05 2:39 PM Page 1

JOURNAL OF THE AUDIO ENGINEERING SOCIETY AES AUDIO/ACOUSTICS/APPLICATIONS VOLUME 53 NUMBER 9 2005 SEPTEMBER

CONTENTS

PAPERS Directional Measurement of Airborne Sound Transmission Paths Using a Spherical Microphone Array...... Bradford N. Gover 787 A spherical microphone array with its narrow beam can be used as a measurement tool to isolate sound leakage between adjoining rooms. Finding weak spots in the separating walls provides a diagnostic means for improving sound isolation. Such weak spots as slits and partial holes were identified in both controlled laboratory situations and real buildings. Minor defects of only a few could be detected. Decomposition of Impulse Responses Using Complex Wavelets...... S. J. Loutridis 796 The continuous wavelet transform converts a one-dimensional audio signal into a two-dimensional presentation, thereby providing more insight into its time–frequency structure. It is especially well suited for the analysis of transient signals. By optimizing the bandwidth of the wavelet filter bank, the impulse response of a loudspeaker, or a room, reveals resonances, coloration, and other problems that would otherwise be hidden. The wavelet transform can be used for envelope extraction, calculation of instantaneous frequency, and power spectral density. Optimal Design and Synthesis of Reverberators with a Fuzzy User Interface for Spatial Audio ...... Mingsian R. Bai and Ganyuan Bai 812 Reverberator architectures, even when capable of achieving high quality, often have dozens of parameters that must be hand adjusted in order to create natural sounding space. To minimize the effort of trial and error in parameter tuning, an automatic search procedure based on genetic algorithms is recommended. A fuzzy logic and graphic user interface was also developed to facilitate users in selecting their favorite room sound. Subjective tests confirmed the quality of the resulting reverberation.

ENGINEERING REPORTS Evaluation of Iterative Methods for Wavetable Matching ...... Simon Wun and Andrew Horner 826 The noniterative approach to wavetable matching produces good results but the computation grows exponentially, whereas the iterative approach is less robust while computation only grows linearly. Several new iterative methods are proposed in order to achieve better quality without excessive computation. This paper describes wavetable matching using iterative enumeration, iterative local search, and seeded iterative local search. Results confirm that there are numerous near optimal wavetable matches.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 836 High-performance serial bus (IEEE 1394); Internet audio quality; forensic audio; loudspeaker measurement and modeling; acoustics and sound-source modeling

FEATURES 26th Conference Report, Denver...... 838 Digital Music Notation Formats...... 849 120th Convention, Paris, Call for Papers...... 880

DEPARTMENTS News of the Sections...... 855 Membership Information...... 868 Upcoming Meetings ...... 862 Advertiser Internet Directory...... 871 Sound Track ...... 863 In Memoriam ...... 879 New Products and Developments...... 865 Sections Contacts Directory ...... 881 Available Literature...... 867 AES Conventions and Conferences ...... 888 p.890_TOC 10/6/05 11:44 AM Page 1

JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS KEE AES HIG VOLUME 53 NUMBER 10 2005 OCTOBER # TO LAS CONTENTS

PAPERS Long Interpolation of Audio Signals Using Linear Prediction in Sinusoidal Modeling ...... Mathieu Lagrange, Sylvain Marchand, and Jean-Bernard Rault 891 A new synthesis technique, based on linear prediction of sinusoidal parameters, is proposed as a means to interpolate missing audio in gaps lasting as long as one second. Recreated musical partials include the expected vibrato and tremolo, thereby creating a natural sound for complex polyphonic signals. This parametric approach is an improvement over the more common methods of sinusoidal and temporal interpolation. Subjects judged the result as being a higher quality. Development and Evaluation of a Model for Predicting the Audibility of Time-Varying Sounds in the Presence of Background Sounds ...... Brian R. Glasberg and Brian C. J. Moore 906 A model for predicting the audibility of a target signal in the presence of a noisy background can be applied to many stimuli, such as announcement signals in aircraft or trains and ring tones of mobile telephones in urban environments. Rather than using a model that assumes steady state, this study considers time-varying signals and background sounds, which have more applications to real situations. However, the complexity of informational masking makes the problem more difficult. Directional Resolution of Head-Related Transfer Functions Required in Binaural Synthesis ...... Pauli Minnaar, Jan Plogsties, and Flemming Christensen 919 When a signal recorded in an anechoic environment is convolved with a pair of head-related transfer functions (HRTFs), the listener experiences a sound source in a virtual space. An infinite number of HRTFs are needed to represent all possible locations. Interpolation among a limited number of HRTFs greatly reduces the need for a complete set, but such an approach assumes knowledge of the spatial resolution of the set and the accuracy of the resulting interpolation. In this study the spatial resolution of the basis set was determined to produce interpolated results that were subjectively identical to actual HRTFs. New Type of Acoustic Filter Using Periodic Polymer Layers for Measuring Audio Signal Components Excited by Amplitude-Modulated High-Intensity Ultrasonic Waves ...... Minoru Toda 930 Because of nonlinearity in acoustic wave propagation, audio frequencies can be generated by strong ultrasonic signals. For example, two signals closely spaced in frequency create an audio signal at the difference frequency as if air were a demodulator. Measuring these demodulation products is difficult because the nonlinearity of microphones also produces similar signals. A new type of acoustic filter using periodic polymer layers greatly reduced the influence of the microphone by providing an acoustic low-pass function. In this paper a detailed theory for multilayer films as a filter confirms the approach.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 942 Tape care and handling; audio preservation and restoration; library and archive systems; audio metadata; audio connectors

FEATURES Program Loudness Revisited ...... 945 The Evolving World of Film Sound ...... 951 New Officers 2005/2006...... 954 Review of Society’s Sustaining Members ...... 958 120th Convention, Paris, Call for Papers...... 992

DEPARTMENTS News of the Sections...... 978 Membership Information...... 986 Sound Track ...... 982 Advertiser Internet Directory...... 989 New Products and Developments...... 983 In Memoriam ...... 991 Available Literature...... 984 Sections Contacts Directory ...... 993 Upcoming Meetings ...... 985 AES Conventions and Conferences ...... 1000 p.1002_TOC.qxd 11/15/05 10:41 AM Page 1

JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS KEE HIG AES # TO VOLUME 53 NUMBER 11 2005 NOVEMBER LAS

CONTENTS

President’s Message ...... Neil Gilchrist 1003

PAPERS Three-Dimensional Surround Sound Systems Based on Spherical Harmonics ...... M. A. Poletti 1004 Based on spherical harmonics, this paper reviews and extends the three-dimensional theory of sound recording and reproduction. Three methods of recording are compared: free-space directional microphone arrays, pressure microphones mounted in a sphere, and free-space arrays with variable radii. An analysis shows that appropriate sound fields can be created without the requirement of dipole loudspeakers. In addition, mode matching can be extended to reverberant environments with nonideal loudspeakers. High-Order Digital Parametric Equalizer Design ...... Sophocles J. Orfanidis 1026 Unlike classical equalizers having first- or second-order filters, using higher order Butterworth, Chebyshev, and elliptic analog prototypes provides flatter passbands and sharper band edges. The analysis shows their advantages. Equalizer coefficients are computed using center frequency, peak gain, bandwidth, and bandwidth gain. The discussions on topology explore transposed, normalized-lattice, and minimum roundoff noise state-space realizations. Design methods apply equally well to low-pass and high-pass shelving filters and to ordinary bandpass and bandstop filters. Stability and Sensitivity Analyses for Diffusers with Single and Multiple Active Elements ...... Mark R. Avis, Lejun Xiao, and Trevor J. Cox 1047 Passive diffusers are used to improve spatial acoustics, but they are limited to mid and high frequencies because of the required depth. Alternatively, by actively controlling the surface impedance with an electronic control system, reflected wave fronts can be dispersed. While active impedance technology has usually been used to absorb sound and cancel noise, it can also be used for sound dispersion. Active diffusers are more difficult to use than active absorbers because of tighter requirements on system accuracy. Test results confirm that the stability of a real system is consistent with the theoretical analysis and that active diffusers are prone to instability.

ENGINEERING REPORTS Acoustic Analysis and Design of Miniature Loudspeakers for Mobile Phones ...... Mingsian R. Bai and Jerwoei Liao 1061 Increasing needs for audio quality in miniature loudspeakers used in mobile phones require tradeoffs not found in conventional large loudspeakers. Miniature loudspeakers have a smaller Bl product, which influences the high-frequency rolloff and sensitivity. An electroacoustic analysis explores a model of the duct structure and head diffraction effects. An acoustic design to extend the low-frequency bandwidth is suggested to increase perceived quality. Large-signal performance appears to be a critical issue.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 1078 Recoding data set for audio bit-rate reduction; digital input/output interfacing; audio connectors; grounding and EMC; storage and handling of media

FEATURES Loudspeaker Array Technology ...... 1081 28th Conference, Piteå, Sweden, Call for Papers ...... 1104

DEPARTMENTS News of the Sections...... 1085 Advertiser Internet Directory...... 1099 Sound Track ...... 1092 In Memoriam ...... 1102 Upcoming Meetings ...... 1092 AES Annual Report ...... 1103 New Products and Developments...... 1093 Sections Contacts Directory ...... 1105 Available Literature...... 1094 AES Conventions and Conferences ...... 1112 Membership Information...... 1095 Dec_TOC.qxd 12/20/05 12:01 PM Page 1

JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS KEE HIG AVOLUME 53E NUMBERS 12 2005 DECEMBER # TO CONTENTS LAS PAPERS Spatial Impulse Response Rendering I: Analysis and Synthesis...... Juha Merimaa and Ville Pulkki 1115 A new processing technique, called spatial impulse response rendering, allows a measured room response to be reproduced using an arbitrary multichannel loudspeaker system. An intermediate representation based on perceptually motivated attributes was derived from the microphone signals—such as from a B-format microphone—and using a convolving reverberator, this representation was then transformed into the loudspeaker signals of the specified configuration. This analysis–synthesis approach used psychophysical rather than physical accuracy. Based on energy analysis, the time-dependent direction of arrival and diffuseness of the room response was analyzed within frequency bands. Perception of Modal Distribution Metrics in Critical Listening Spaces—Dependence on Room Aspect Ratios...... B. M. Fazenda, M. R. Avis, and W. J. Davies 1128 To minimize the influence of low-frequency resonances in small listening rooms that are used for monitoring, designers sometimes optimize the aspect ratio to control the location of resonances. Such optimizations are based on a figure of merit that considers the modal distribution of resonances. Using three virtual rooms, which scored at the extremes of these metrics, the utility of these metrics was examined. The results showed that ranking of rooms was misleading because of a strong dependence on spectral content of the program material. Regardless of the statistics of modal resonances, if the program excited a resonance, it was perceived. Artificial Reverberation Control Using Cepstrum Decomposition While Maintaining Locations of Peaks and Dips on the Frequency Responses ...... Yoshinori Takahashi and Mikio Tohyama 1142 Rendering and morphing the room reverberation characteristics is a key component for modeling acoustic events in a virtual space. Rather than use the typical techniques for changing the response, the authors propose a modification of a reference response as a means for changing spatial properties. By increasing or decreasing the peaks and valleys in the frequency response, the effective reverberation time in a given frequency band is correspondingly modified. Hence, the personality of the room is preserved even as the response is morphed. ENGINEERING REPORTS Subjective Testing of Compression Drivers...... Earl R. Geddes, Lidia W. Lee, and Roberto Magalotti 1152 Although it is known that compression drivers produce both linear and nonlinear distortion, engineers assume that both of these degradations are audible and must therefore be minimized. However, a double-blind subjective test showed that listeners could not detect nonlinear distortion. Rather, only linear distortions (differences in frequency response) were significant. This unexpected result has implications for designers who are maximizing perceived quality while minimizing manufacturing cost. STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 1163 Forensic audio; digital audio in ATM networking; ATM over Ethernet; digital audio measurements; audio file exchange; audio over IEEE1394; acoustics and sound source modeling FEATURES 27th Conference Report, Hillerød, Denmark ...... 1166 119th Convention Report, New York ...... 1174 Exhibitors ...... 1190 Technical Program...... 1196 Audio Processing for the Hearing Impaired...... 1242 Education News...... 1251 Call for Nominations for the Board of Governors...... 1258 Call for Awards Nominations...... 1259 28th Conference, Piteå, Sweden, Call for Papers ...... 1267 Bylaws: Audio Engineering Society, Inc...... 1269 Index to Volume 53 ...... 1273 DEPARTMENTS Reviews of Acoustical Patents...... 1158 Available Literature...... 1256 News of the Sections...... 1247 Advertiser Internet Directory...... 1257 Upcoming Meetings ...... 1250 Membership Information...... 1260 Sound Track ...... 1253 Sections Contacts Directory ...... 1289 New Products and Developments...... 1255 AES Conventions and Conferences ...... 1296 J-F2006_TOC.qxd 2/1/06 4:22 PM Page 1

JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS KEE HIG AVOLUME 54E NUMBERS 1/2 2006 JANUARY/FEBRUARY # TO CONTENTS LAS PAPERS Spatial Impulse Response Rendering II: Reproduction of Diffuse Sound and Listening Tests ...... Ville Pulkki and Juha Merimaa 3 A proposed technique for spatial impulse response rendering, called SIRR, introduced in a previous article, is examined and evaluated in two listening tests. Based on the analysis presented, a hybrid method consisting of amplitude panning at low frequencies and phase randomization at high frequencies was implemented. In the first test, conducted in an anechoic chamber, the SIRR technique performed best in reproducing a reference virtual reality. In the second test, measured responses of existing spaces were reproduced with SIRR and other techniques. SIRR reproduction was judged most natural, especially at off-center listening. A Hybrid Time–Frequency Domain Approach to Audio Time-Scale Modification ...... David Dorran, Robert Lawlor, and Eugene Coyle 21 Increasing or decreasing audio delivery rate without changing the pitch can be achieved by processing the audio in either the frequency or time domain. While time-domain approaches are both efficient and without artifacts, they require the presence of a strong quasi-periodic component. In contrast, frequency-domain approaches work over a wide range of signal types but tend to produce reverberantlike artifacts. A new hybrid approach combines the advantages of both approaches, especially for speech, without requiring an a priori knowledge of the signal. Effects of Headtracker Latency in Virtual Audio Displays ...... Douglas S. Brungart, Alex J. Kordik, and Brian D. Simpson 32 In the design of headtracked virtual auditory displays, the latency between head movement and the corresponding image shift can be extremely critical. A series of experiments showed that latency of about 70 ms begins to impair localization ability and becomes noticeable to the listener. While this threshold varies among listeners and types of audio signals, it suggests that headtracker latency is generally not a limiting factor for creating a quality image in state-of-the-art audio display systems, which typically exhibit latency values of less than 30 ms. ENGINEERING REPORTS Active All-Pass Crossover Networks with Equal Resistors and Equal Capacitors ...... René Christensen 45 Active crossover networks can be constructed with all-pass functions and with the additional constraint that resistors and capacitors have the same value. Two such networks are examined: a fourth-order three-way filter and a sixth-order four-way filter. While the transient responses are not perfect, compared to the familiar Linkwitz–Riley configuration, the group delays are significantly smoother for filters of the same order. CORRECTIONS Correction to “Spatial Impulse Response Rendering I: Analysis and Synthesis” ...... Juha Merimaa and Ville Pulkki 54

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 55 Life expectancy of MO and recordable compact discs; unique identifiers in AES3; loudspeaker measurements FEATURES Audio Forensics...... 56 Audio Networking: Applications and Requirements...... Kevin Gross 62 Reprint of “Speech Reinforcement in St. Paul’s Cathedral” ...... P. H. Parkin and J. H. Taylor 67 29th Conference, Seoul, Call for Papers...... 95 121st Convention, San Francisco, Call for Papers ...... 96 DEPARTMENTS News of the Sections...... 76 Membership Information...... 87 Sound Track ...... 80 Advertiser Internet Directory...... 91 Upcoming Meetings ...... 82 Sections Contacts Directory ...... 97 New Products and Developments...... 82 AES Conventions and Conferences ...... 104 Available Literature...... 83 p.106_TOC_Mar.qxd 3/2/06 2:51 PM Page 1

JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS KEE HIG AVOLUME 54E NUMBERS 3 2006 MARCH # TO LAS CONTENTS

PAPERS Modulation and System Techniques in PWM and SDM Switching Amplifiers...... Malcolm Hawksford 107 Switching amplifiers that use either sigma–delta modulation (SDM) or pulse-width modulation (PWM) can be modeled in terms of linear angle modulation. Distortion generated when applying feedback to PWM is demonstrated, and strategies to improve linearity are then presented. Also, a look-ahead SDM incorporating an energy-balancing binary decision threshold is examined. A unified analytic approach shows that SDM can compete in terms of linearity with PWM power amplifiers and that energy-balancing SDM can achieve similar peak signals. A Search for Best Error Metrics to Predict Discrimination of Original and Spectrally Altered Musical Instrument Sounds...... Andrew B. Horner, James W. Beauchamp, and Richard H. Y. So 140 Knowing the required accuracy of harmonic components in decoded or synthesized periodic audio signals allows a designer to select an optimum strategy. An error metric of spectral accuracy was proposed and evaluated in subjective listening tests. Listeners were asked to discriminate sounds with randomly altered changes in spectral amplitude without any changes in the average spectrum or overall loudness. These tests confirmed the validity of the model. Advanced Simulation of a Condenser Microphone Capsule ...... Roger S. Grinnip III 157 An advanced model of a pressure condenser microphone capsule was used to simulate the performance of an experimental prototype. The external acoustic domain was modeled using the boundary-element method, which allowed the capsule to have an arbitrary shape. The results show excellent agreement throughout the measured frequency range. This coupled model was better than the conventional lumped-element techniques. Bit-Rate Scalable Intraframe Sinusoidal Audio Coding Based on Rate-Distortion Optimization ...... Richard Heusdens, Jesper Jensen, W. Bastiaan Kleijn, Valery Kot, Omar A. Niamut, ...... Steven van der Par, Nicolle H. van Schijndel, and Renat Vafin 167 A parametric coder based on rate-distortion optimal sinusoid + noise coding of audio and speech signals is presented. The coder minimizes a perceptual distortion measure subject to a bit-rate constraint. A variable-length signal analysis is used to avoid preechoes and to reduce the intersegment correlation. Frequency differential coding is performed to exploit intrasegment correlations. In subjective listening tests using music and speech, this method often performed better than state-of-the-art MPEG-4 audio coders.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 189 ATM networking; digitally-interfaced microphones; microphone specifications; Standards meetings

FEATURES 12th Tokyo Regional Convention Report...... 190 Exhibitors ...... 194 Program...... 196 120th Convention Preview, Paris...... 208 Exhibit Previews ...... 210 Stereophonic Recording Techniques: Old Challenges, New Approaches...... 225 29th Conference, Seoul, Call for Papers...... 247 121st Convention, San Francisco, Call for Papers ...... 248

DEPARTMENTS News of the Sections...... 230 Advertiser Internet Directory...... 239 Upcoming Meetings ...... 233 In Memoriam ...... 245 Sound Track ...... 234 Sections Contacts Directory ...... 249 Available Literature...... 236 AES Conventions and Conferences ...... 256 Membership Information...... 238 p.258_TOC_Apr.qxd 4/4/06 11:52 AM Page 1

JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS KEE HIG AVOLUME 54E NUMBERS 4 2006 APRIL # TO LAS CONTENTS

PAPERS A Hybrid Technique for Validating Unidimensionality of Perceived Variation in a Spatial Auditory Stimulus Set ...... Tobias Neher, Tim Brookes, and Francis Rumsey 259 Having a set of audio stimuli that varies along a specified single perceptual dimension, regardless of variations in physical acoustic parameters, would be extremely useful in subjective experiments that require training or reference stimuli. After considering various paradigms for validating such a set, a hybrid technique comprising multidimensional scaling and subject-specific verbalizations proved to be the most promising. This technique was developed further and experiments demonstrated that it revealed which groups of stimuli vary as intended along a single perceptual dimension and which vary along multiple dimensions. Spatially Modulated Auditory Alerts for Aviation ...... Durand R. Begault, Mark R. Anderson, and Bryan U. McClain 276 Detection of a nonspeech auditory alert (alarm) in a noisy environment increases when such an alert is moved along a virtual spatial trajectory using a 3-D auditory display. This approach decreases thresholds by as much as 8 dB because of dynamic changes in level and interaural cross-correlation of the signals at the two ears.

ENGINEERING REPORTS Dynamic Crosstalk Cancellation for Binaural Synthesis in Virtual Reality Environments ...... Tobias Lentz 283 In order to create a 360-degree virtual reality with free listener movement, a system was designed with a combination of dynamic head-tracking crosstalk cancellation and binaural synthesis of spatial environments. Rather than use two loudspeakers with limited rotational range, the proposed system uses two pairs of loudspeakers with dynamic crossfading as the listener rotates his head through eight sectors. Preliminary tests in an environment with reflections demonstrate the feasibility of the approach. Model Optimization of Distributed-Mode Loudspeaker Using Attached Masses ...... Suzhen Zhang, Yong Shen, Xiaoxiang Shen, and Jinglei Zhou 295 While distributed-mode loudspeakers have many advantages compared with conventional cone topology, they usually have excessive fluctuation in frequency response. By attaching area masses, resonances in selective frequency regions can be distributed more evenly, and the excessive fluctuation is reduced. A generic algorithm has been developed to optimize the position, weight, and number of such masses. Simulated results using FEMLAB were experimentally tested in an anechoic chamber, thus validating the approach to improving distributed-mode topologies.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 306 Unique identifiers in AES3; audio in ATM networks; audio metadata; forensic audio

FEATURES 28th Conference Preview, Piteå, Sweden ...... 308 Calendar ...... 311 Program...... 312 Audio Power Amplification ...... 319 30th Conference, Saariselkä, Finland, Call for Papers...... 336

DEPARTMENTS News of the Sections...... 324 Membership Information...... 334 Upcoming Meetings ...... 328 Advertiser Internet Directory...... 335 Sound Track ...... 329 Sections Contacts Directory ...... 337 New Products and Developments...... 331 AES Conventions and Conferences ...... 344 Available Literature...... 332 p.346_TOC_May.qxd 5/2/06 10:57 AM Page 1

JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS

AVOLUME 54E NUMBERS 5 2006 MAY O

CONTENTS

PAPERS Low-Frequency Optimization Using Multiple Subwoofers...... Todd Welti and Allan Devantier 347 The acoustic environment of a sound system has a strong influence on the sound quality at low frequencies, especially in small spaces. As a result there is an interest in solutions that improve the performance. While conventional approaches tend to focus on signal processing, the proposed solution introduces the location of subwoofers as the major variable, with the addition of minimal signal processing. Using a metric that optimizes performance in multiple seats, a robust solution becomes available. Identification of Quality Attributes of Spatial Audio by Repertory Grid Technique ...... Jan Berg and Francis Rumsey 365 In order to evaluate spatial quality of audio reproduction, it is first necessary to select a method that can identify the relevant attributes. Being a relatively new field, spatial audio does not yet have a well-established list of such attributes. As an extension of the work of Kelly, the authors apply the repertory grid technique, which is based on subjects’ personal reflections of the stimuli. Because subjects describe the way in which triads of stimuli differ, the attributes are elicited rather than constructed by the experimenter. The results are consistent with the findings from other methods utilized, thus demonstrating the validity of this approach when used in spatial audio. Conversion of Discretely Sampled Sound Field Data to Auralization Formats ...... Bård Støfringsdal and U. Peter Svensson 380 Sound field simulations often use finite-element or other mesh-based methods, which produce output data that must first be converted to an intermediate format in order to be compatible with conventional auralization techniques. The proposed method converts sampled mesh data to a series of plane waves using a circular array of virtual sources. While not a perfect conversion of an arbitrary sound field, this approach provides a stable frequency-domain representation which minimizes the error in a least squares sense. Such reproduction errors should be acceptable in most practical cases. Results for two dimensions are readily extensible to three dimensions. Compensating the Response of Near-Field Loudspeaker Monitors to Minimize the Effects of Desktop Acoustic Loading ...... Andrew Goldberg, Aki Mäkivirta, and Ari Varla 401 When two-way loudspeakers are mounted on or near mixing consoles, acoustical loading detrimentally changes the response. Acoustical loading systematically raises the response in the 100- to 250-Hz region, and reflections at mid and high frequencies make a comb filtering effect. In an extensive study, 80% of the cases exhibited low-frequency one-sixth octave peaks of about 4 to 6 dB. A single second-order notch filter, appropriately designed, removes much of the negative effects of nearby mixing consoles, desktops, and work surfaces. LETTERS TO THE EDITOR Comments on “Perception of Modal Distribution Metrics in Critical Listening Spaces— Dependence on Room Aspect Ratios”...... Earl Geddes 412 Authors’ Reply ...... B. M. Fazenda, M. R. Avis, and W. J. Davies 412

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 414 Audio file format for interchange; high-resolution multichannel audio interconnection (HRMAI)

FEATURES Automotive Audio Update...... 416 Loudness Trumps Everything ...... 421 30th Conference, Saariselkä, Finland, Call for Papers...... 440

DEPARTMENTS News of the Sections...... 424 Membership Information...... 431 Sound Track ...... 428 Advertiser Internet Directory...... 437 New Products and Developments...... 429 Sections Contacts Directory ...... 441 Upcoming Meetings ...... 429 AES Conventions and Conferences ...... 448 Available Literature...... 430 p450_revisedTOC_June.qxd 6/7/06 11:38 AM Page 1

JOURNAL OF THE AUDIO ENGINEERING SOCIETY KEE AUDIO/ACOUSTICS/APPLICATIONS HIG # TO AVOLUME 54E NUMBERS 6 2006 JUNE LAS

CONTENTS

PAPERS Loudspeakers and Rooms for Sound Reproduction—A Scientific Review...... Floyd E. Toole 451 Much of our understanding of how listeners hear spatial acoustics originates from studies with large spaces, notably concert halls. While the resulting insights are frequently extended to small spaces, other phenomena weaken the validity of conclusions. Listeners may be adapting to the complexities of reflections and resonances in small spaces, thereby reducing or eliminating the perception of measured degradation. Informal evidence from the professional recording industry suggests that humans compensate and adapt to the acoustical anarchy of complex sound fields. A Comparison of the “Pruned Tree” versus “Stack” Algorithms for Look-Ahead Sigma–Delta Modulators...... J. A. S. Angus 477 High-order Sigma–Delta modulators, used in high-quality converters, cannot use aggressive noise-shaped filtering because the one sample delay in the feedback produces instability under overload conditions. Various solutions have been proposed, but computational burdens grow exponentially with increases in the look-ahead depth. Pruning the choices reduces the burden but at the risk of discarding the optimum choice. A comparison of the “pruned tree” and the “stack” algorithms shows that the former is most efficient even though the latter has better theoretical performance. Evaluation of Sound Quality, Boominess, and Boxiness in Small Rooms ...... Adam Weisser and Jens Holger Rindel 495 Subjective listening tests were conducted in seven small rooms to investigate those physical attributes that correspond to the perception of boominess and boxiness. Three new acoustic metrics—small room bass ratio, small room early decay time ratio, and low–high ratio—proved to be better predictors of sound quality than conventional measures. However, the type of audio, namely music or speech, influenced preference and quality judgments. Speech was best in rooms with weak reverberation, whereas a preferred range of reverberation was found for music.

ENGINEERING REPORTS Effect of Reflectors on Sound-Source Localization with Two Microphones ...... Sandeep A. Phatak, Rama Ratnam, Bruce C. Wheeler, William D. O’Brien, Jr., and Albert Feng 512 The performance of algorithms that extract source location using a pair of microphones degrades in either reverberant conditions or the presence of parallel reflectors. Localization of signals such as white noise, which are very broadband, is more robust than with speech, which can be narrow band. Reverberation produces excessive temporal smearing at low frequencies. Finally, the localization–extraction algorithm, which is frequency-based, proved more reliable than the commonly used multiple signal classification algorithm.

FEATURES 29th Conference Preview, Seoul ...... 526 Calendar ...... 528 Program...... 530 Registration Form...... 535 Enhanced Multichannel Audio ...... 536 Surround Sound: A Chance for Enhanced Creativity ...... 540

DEPARTMENTS News of the Sections...... 542 Upcoming Meetings ...... 550 Sound Track ...... 546 Membership Information...... 551 New Products and Developments...... 548 Sections Contacts Directory ...... 560 Available Literature...... 549 AES Conventions and Conferences ...... 568 Advertiser Internet Directory...... 549 JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS

AVOLUME 54E NUMBERS 7/8 2006 JULY/AUGUST

CONTENTS PAPERS A Robust and Computationally Efficient Speech/Music Discriminator ...... Jayme Garcia Arnal Barbedo and Amauri Lopes 571 Discriminating between speech and music is critical in such applications as speech recognition and automatic music transcription. A new method for achieving discrimination, which is computationally simple, attains almost perfect performance on a wide range of samples. The strategy uses four features extracted from frame histograms: zero-crossing rate, spectral rolloff, perceived loudness, and fundamental frequencies. Modest latency allows the strategy to be used in real-time applications. Vibrations of Loudspeaker Cones in the Transitional Range...Zhi-Liang Zhang and Chang-Jun Cheng 589 Loudspeaker diaphragm vibrations are analyzed in the transitional frequency region where bending waves are beginning to play a significant role in relation to the longitudinal motion. An analytic and numeric analysis shows that the two types of motion are highly coupled. The first nonbending frequency can be considered to be the upper limit of the loudspeaker’s frequency response. Real-Time Processing of Image Sources Using Binary Space Partitioning ...... Dirk Schröder and Tobias Lentz 604 Unlike the acoustic simulation of virtual spaces for static environments, with fixed source and listener locations, interactive virtual reality requires the aural experience to match a dynamically changing visual scene. Rapid computations are therefore more important than detailed acoustic modeling of a space. In the approach the geometry of a scene is subdivided into small subdivisions and pre-encoded in optimized data structures, BSP trees, with image source data.

ENGINEERING REPORTS Cumulative Spectral Analysis for Transient Decaying Signals in a Transmission System Including a Feedback Loop ...... Yoshinori Takahashi, Mikio Tohyama, and Yoshio Yamasaki 620 Determining the principle resonant frequency of a before the beginning of howling is a valuable tool. By introducing a spectral accumulation function into the previously known technique of cumulative spectral analysis (used with loudspeakers), potential resonant frequencies are more clearly revealed even when they are only barely audible. When applied to the decaying portion of a speech signal, the display clearly predicts the principle resonance. Effectively, the technique increases the order of resonant poles.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 630 True peak metering; digital interface for microphones; ATM network over Ethernet; IEEE 1394 use cases; digital audio measurements; digital audio input-output interfaces; audio-file transfer and exchange; transfer technologies

FEATURES 120th Convention Report, Paris ...... 642 Exhibitors...... 660 Program ...... 663 121st Convention Preview, San Francisco...... 742 Exhibit Previews...... 744 Digital Radio Broadcasting...... 771

DEPARTMENTS Reviews of Acoustical Patents...... 636 Membership Information...... 785 News of the Sections...... 775 Advertiser Internet Directory...... 787 Sound Track ...... 781 Sections Contacts Directory ...... 792 Available Literature...... 782 AES Conventions and Conferences ...... 800 Upcoming Meetings ...... 784 p802_TOC_Sept.qxd 8/23/06 10:05 AM Page 1

JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS

AVOLUME 54E NUMBERS 9 2006 SEPTEMBER CONTENTS PAPERS Perception and Analysis of Selected Auditory Events with Frequency-Dependent Directions ...... Toni Hirvonen and Ville Pulkki 803 A study of a single auditory event created by an array of 11 loudspeakers distributed along the azimuth revealed some new information on the perception of source width and sound location. The source location with highest and lowest frequencies dominates the perceived distribution of sound, and frequency bands were also spatially integrated to a narrower perceived source than in reality. With click stimulus, the source was perceived very narrow, although the clicks were distributed widely around the listener. The traditional cross-correlation model was tested with the stimuli, and the results did not match the perceived auditory objects in general. Extraction of Auditory Features and Elicitation of Attributes for the Assessment of Multichannel Reproduced Sound...... Sylvain Choisel and Florian Wickelmaier 815 Although there is extensive research on the auditory features of multichannel sound reproduction, scientists are still examining the philosophical and practical issues of various methods. A new approach, perceptual structure analysis, is based on subjective evaluation of triads of sounds without first requiring verbal descriptors, unlike the more traditional repertory grid technique. By testing the consistency of the judgments, it is possible to assess the listener's ability to identify the features. While a conclusive comparison of the attributes obtained by the two elicitation methods would require a larger number of participants, it was possible to derive a common set of eight attributes. Frequency-Domain Algorithms for Audio Signal Enhancement Based on Transient Modification ...... Michael M. Goodwin and Carlos Avendano 827 In contrast to the conventional definition of audio enhancement as improving an objective measure of signal quality, this study treats enhancement as an artistic freedom used by either professionals or listeners. Two examples of spectral-based transient manipulation demonstrate this concept. In the first case, a transient characterization analysis is used to drive frequency-dependent modifications. In the second case, the modulation spectrum is manipulated by modifying the time trajectories of spectral envelopes. Such enhancements change the aural experience without introducing artifacts. Noise Power Modulation in Dithered and Undithered High-Order Sigma–Delta Modulators ...... Ivar Løkken, Anders Vinje, and Trond Sæther 841 Optimizing high-order sigma–delta modulators often focuses on quantizer distortion and idle tones while ignoring the consequences of noise power modulation. This study focuses on simulations of noise modulation in the baseband for various topologies with and without dither. The assumption that high-order dithering in sigma–delta modulators is equivalent to the corresponding dithering in linear pulse-code modulation proved to be erroneous. Noise power modulation must be simulated for each implementation when optimizing the loop filter and dithering strategy.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 855 AESSC vice chair; audio file format; audio disk format; AES3 using coaxial cable; sample-accurate timing in AES47; audio applications of IEEE 1394; forensic audio; loudspeaker measurement

FEATURES 28th Conference Report, Piteå, Sweden...... 858 Next Generation of Audio Communications ...... 865 Education News...... 868 122nd Convention, Vienna, Call for Papers...... 893 31st Conference, London, Call for Papers ...... 894

DEPARTMENTS News of the Sections...... 869 Membership Information...... 882 Upcoming Meetings ...... 875 Advertiser Internet Directory...... 885 Sound Track ...... 876 In Memoriam ...... 891 Available Literature...... 878 Sections Contacts Directory ...... 896 New Products and Developments...... 880 AES Conventions and Conferences ...... 904 p906_TOC_Oct.qxd 10/11/06 12:45 PM Page 1

JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS

AVOLUME 54E NUMBERS 10 2006 OCTOBER CONTENTS TUTORIALS Tutorial: Loudspeaker Nonlinearities—Causes, Parameters, Symptoms ...... Wolfgang Klippel 907 This comprehensive review and tutorial discussion about nonlinear distortion in loudspeakers offers a clear perspective: under the right conditions, measurements may manifest particular nonlinear electromechanical mechanisms. Because there are a large number of such mechanisms, signals must be carefully selected to excite particular nonlinearities. A catalog of observable manifestations provides a working recipe for diagnosing defects, which then makes possible design improvement. Three examples illustrate this approach. PAPERS Efficient Resonant Loudspeakers with Large Form-Factor Design Freedom ...... Ronald M. Aarts, Joris A. M. Nieuwendijk, and Okke Ouweltjes 940 It is not possible to combine high efficiency and wide frequency bandwidth in small cabinet loudspeakers. However, by changing assumptions and allowing nonlinear electronic processing, a small loudspeaker can operate in the high-efficiency spectral region. Compressing the 2.5-octave region from 20 to 120 Hz into a narrow frequency at the natural resonances of the loudspeaker provides a means for optimizing both size and efficiency. However, acoustic quality at low frequencies is compromised. An experimental prototype illustrates the approach. Vibrotactile Enhancement of Auditory-Induced Self-Motion and Spatial Presence ...... Aleksander Väljamäe, Pontus Larsson, Daniel Västfjäll, and Mendel Kleiner 954 Using cross-modal stimulation of multiple senses can enhance the illusion of motion in entertainment and virtual environments. Mechanically induced vibrations significantly improve the sense of self-motion and presence. Since vestibular excitation is not possible when not actually moving, auditory and tactile sensations can enhance an illusion of movement and presence in virtual environments. Examples of using three audio-tactile scenes illustrate the degree to which an illusion of movement is created. ENGINEERING REPORTS Virtual Air Guitar ...... Matti Karjalainen, Teemu Mäki-Patola, Aki Kanerva, and Antti Huovilainen 964 Playing a virtual guitar by tracking hand motions illustrates an approach to a natural user interface for synthesized music. Three different methods for sensing hand motion and position have been tried: data gloves in a virtual room, optical tracking of hand movement, and special control sticks that sense acceleration. Of these, optical tracking with a web camera offers the least expensive approach, since such devices are often part of a computer system. Demonstration systems at Heureka Science Center have allowed thousands of visitors to enjoy the feeling of being a rock star. Eventually, this approach may lead to the evolution of professional musical instruments. LETTERS TO THE EDITOR Comments on “Model Optimization of Distributed-Mode Loudspeaker Using Attached Masses” ...... Frank Fahy 981 Authors’ Reply...... Suzhen Zhang and Yong Shen 981 Comments on “Low-Frequency Optimization Using Multiple Subwoofers” ...... Earl R. Geddes 983 Authors’ Reply ...... Todd Welti and Alan Devantier 984 CORRECTIONS Corrections to “Noise Power Modulation in Dithered and Undithered High-Order Sigma–Delta Modulators” ...... Ivar Løkken, Anders Vinje, and Trond Sæther 985 STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 986 Acoustics and sound-source modeling; audio connectors; grounding and EMC FEATURES Binaural Technology for Mobile Applications...... 990 New Officers 2006/2007...... 996 Review of Society’s Sustaining Members ...... 1001 122nd Convention, Vienna, Call for Papers...... 1037 31st Conference, London, Call for Papers ...... 1038 32nd Conference, Hillerød, Call for Papers...... 1039 DEPARTMENTS Reviews of Acoustical Patents...... 987 Membership Information...... 1032 News of the Sections...... 1023 Advertiser Internet Directory...... 1035 Upcoming Meetings ...... 1026 In Memoriam ...... 1036 Sound Track ...... 1027 Sections Contacts Directory ...... 1040 New Products and Developments...... 1030 AES Conventions and Conferences ...... 1048 Available Literature...... 1031 p1050_TOC_Nov.qxd 11/7/06 12:42 PM Page 1

JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS

AVOLUME 54E NUMBERS 11 2006 NOVEMBER

CONTENTS

PAPERS Multiple-Loudspeaker Playback of Stereo Signals ...... Christof Faller 1051 In order to avoid the legacy of the implied loudspeaker configuration for traditional stereo signals, they can be decomposed into virtual sources. Such spatial decomposition allows a resynthesis to match to a new loudspeaker configuration, especially with additional front loudspeakers. Uncorrelated signal components, corresponding to ambiance, drive the side loudspeakers. Subjective tests illustrate that listeners prefer the new system not only when outside of the sweet spot, but also at the sweet spot. Structural and Acoustic Analysis of Multiactuator Panels ...... Martin Kuster, Diemer de Vries, Daniel Beer, and Sandra Brix 1065 The requirement of a large number of loudspeakers for wavefield synthesis can be achieved using transducers composed of panels with multiple actuators. The proposed transducers are flat, lightweight sandwich panels driven by an array of exciters. Ideally, each exciter should generate a well-defined point source of radiation. Using a vibrometer, it was shown that the influence of neighboring exciters and panel edges are minimal. Large damping losses, which are critical for making multiple exciters independent, were found to be appropriate for this application. A single panel is a viable alternative for an array of conventional loudspeakers. Synthesis and Implementation of Virtual Bass System with a Phase-Vocoder Approach ...... Mingsian R. Bai and Wan-Chi Lin 1077 Small multimedia loudspeakers and handheld players cannot reproduce low frequencies without also creating nonlinear distortion that results when overdriving their limited dynamic range. However, the human auditory system can extrapolate missing low-frequency fundamentals from higher overtones, so-called residual pitch, thereby creating the impression of the missing bass. Using a phase vocoder, low-frequency components are used to create three overtones to simulate the loudness of the missing component. Subjective tests showed that this approach produced better timbral quality than the traditional approach of nonlinear processing of low frequencies to generate bass sensation.

ENGINEERING REPORTS Validation of ITU-T P.563 Single-Ended Objective Speech Quality Measurement ...... Antti Kurituu 1092 Assessing the audio quality of telecommunication networks using the P.563 standard, which does not require access to the original signal, offers the advantage of simplicity, efficiency, and objectivity. This study examines the relationship of the P.563 metric to the corresponding results obtained from subjective listening tests. Unfortunately, although showing the correct trends, P.563 metric presents results on a compressed scale compared to the subjective quality range, thereby greatly reducing its utility in evaluating narrow-band telephony applications presented in the paper. Refinements to P.563 are required when assessing speech quality.

STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 1099 AES53 sample-accurate timing; storage and handling of media; digital library and archive systems; audio metadata; microphone measurement; digital audio measurement; audio-file exchange

FEATURES Using Game-Audio Tools to Build Audio Research Applications...... Michael Kelly 1102 Preventing Hearing Loss ...... 1109 32nd Conference, Hillerød, Call for Papers...... 1127

DEPARTMENTS News of the Sections...... 1114 Advertiser Internet Directory...... 1123 Upcoming Meetings ...... 1117 AES Awards ...... 1125 Sound Track ...... 1118 AES Annual Report ...... 1126 Available Literature...... 1120 Sections Contacts Directory ...... 1128 New Products and Developments...... 1121 AES Conventions and Conferences ...... 1136 Membership Information...... 1122 p1138_TOC_Dec.qxd 12/18/06 3:43 PM Page 1

JOURNAL OF THE AUDIO ENGINEERING SOCIETY AUDIO/ACOUSTICS/APPLICATIONS AVOLUME 54E NUMBERS 12 2006 DECEMBER CONTENTS President’s Message...... Wieslaw Woszczyk 1139 PAPERS Equalization in an Extended Area Using Multichannel Inversion and Wave Field Synthesis ...... E. Corteel 1140 Because of the nonideal directivity of loudspeakers in wave field synthesis, the conventional approach of individually equalizing each loudspeaker does not produce an accurate soundfield over an extended area of the listening space. A new method for equalization considers the full array of loudspeakers as a complete multiple-input multiple-output (MIMO) system. In the proposed multichannel inversion scheme, compensation is achieved for a limited ensemble of elementary virtual sources. Results show that the approach reduces rendering artifacts and spectral coloration over an extended listening area. Filter Design Method for Loudspeaker Equalization Based on IIR Parametric Filters ...... Germán Ramos and José J. López 1162 Equalizing a loudspeaker using a cascade sequence of second-order sections (low-pass, high-pass, or peak filter) is a viable alternative to the more conventional approach of a single large FIR filter. In order to optimize the parameters of each filter section, a two-step algorithm begins by first searching for a good initial solution and then applying a heuristic method using subjective criteria. The solution is scalable, subjectively validated, and produces a computational cost reduction in comparison to the conventional approach for the same degree of performance. Perceptually Biased Linear Prediction...... Arijit Biswas and Albertus C. den Brinker 1179 In contrast to the standard linear prediction-based perceptual audio coding that uses a separate psychoacoustic model, the authors propose Laguerre-based linear prediction employing a perceptually biased solution. This greatly reduces the computational complexity because a separate psychoacoustic model is no longer required. Subjective listening tests show that the resulting audio quality is similar to that of the traditional approach. ENGINEERING REPORTS Application and Verification of the Objective Quality Assessment Method According to ITU Recommendation Series ITU-T P.862 ...... Antti Kurittu, Juha Salmela, Olli Kirla, Ari Lakaniemi, Ville-Veikko Mattila, and Nick Zacharov 1189 In recent years a number of speech quality prediction algorithms have been developed for evaluating telecommunications systems. The family of ITU-T recommendation P.862 is frequently used to create a mean opinion score of quality. Although these algorithms have been evaluated under common testing conditions for narrow- and wide-band speech signals, care must be used when these standards are applied to channels more specialized degradations, such as spectral aberrations, time scaling, and environmental noise. This study has discovered certain cases of suboptimal accuracy. As with the use of all quality-metric tools, the user must heed their limitations and scope of applicability in order to avoid erroneous conclusions. LETTERS TO THE EDITOR Comments on “Smart Digital Loudspeaker Arrays”...... D. B. (Don) Keele, Jr. 1203 STANDARDS AND INFORMATION DOCUMENTS AES Standards Committee News...... 1215 Personal computer audio quality measurements; storage environment for multiple media; polarity of audio signals; connectors for loudspeaker patch panels; analog recording; transfer technologies; storage and handling of media; digital library and archive systems; microphone measurement and characterization FEATURES 121st Convention Report, San Francisco...... 1218 Exhibitors...... 1235 Program ...... 1241 30th Conference Preview, Saariselkä, Finland...... 1294 Calendar ...... 1296 Program...... 1297 Registration Form...... 1304 Forging Ahead with Spatial Audio Coding...... 1305 Education News...... 1314 Call for Nominations for the Board of Governors...... 1318 Call for Awards Nominations...... 1319 13th Regional Convention, Tokyo, Call for Papers ...... 1324 Bylaws: Audio Engineering Society, Inc...... 1325 Index to Volume 54 ...... 1329 DEPARTMENTS News of the Sections...... 1309 Membership Information...... 1320 Upcoming Meetings ...... 1313 Advertiser Internet Directory...... 1322 Sound Track ...... 1315 Sections Contacts Directory ...... 1344 New Products and Developments...... 1317 AES Conventions and Conferences ...... 1352