2005 April, Volume 53 Number 4

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
News of the Sections   345
Sound Track   348
New Products and Developments   350
Available Literature   352
Membership Information   355
In Memoriam   360
Sections Contacts Directory   361
AES Conventions and Conferences   368

FPO For the cover:

2005 April, Volume 53 Number 4

spine: 2005 April, Volume 53 Number 4