2001 December, Vol 49 Number 12

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

Sound Track   1270

New Products and Developments   1271

Upcoming Meetings   1273

Available Literature   1273

Membership Information   1277

Advertiser Internet Directory   1278

AES Conventions and Conferences   1296

FPO For the cover:

2001 December, Vol 49 Number 12

spine: 2001 December, Vol 49 Number 12