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 configurations for acoustic radiation beam control.

A Dual-Band Equalizer for Loudspeakers
Peng Wang, Wee Ser, and Ming Zhang 917

Many of the digital equalizers for loudspeaker systems are unable to effectively equalize
low-frequency components. A new method is proposed which incorporates a warped filter into the
conventional equalizer design. Computer simulation results indicate that the proposed method
can improve the performance of the equalized response at low frequencies, 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 upper frequency limit. These and other improvements have
been installed in a cabinet which occupies the same footprint 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 wavetable-filter synthesis model. The study examines the best
combination of wavetables followed by a time-varying filter for computation and storage efficiency.
It is shown that devoting all of the computation and memory to the wavetables 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 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 Optical media; magnetic media; mechanical media 941

Call for Comment on REAFFIRMATION of AES-10id-1995, AES information document for digital audio
engineering's 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 Blesser and Derek Pilkington 946

AES Officers 2000/2001 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

Upcoming Meetings 981

News of the Sections 982

Sound Track 987

New Products and Developments 988

Available Literature 989

Membership Information 991

Advertiser Internet Directory 995

Audio Engineering Society Membership Application Instructions 999

Sections Contacts Directory 1002

AES Conventions and Conferences 1008

FPOFor the cover:

Volume 48 Number 10 2000 October

spine: Volume 48 Number 10 2000 October