1998 November, VOLUME 46 NUMBER 11

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 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.

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 1 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
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