2005 September, Volume 53 Number 9

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 decibels 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
Upcoming Meetings   862
Sound Track   863
New Products and Developments   865
Available Literature   867
Membership Information   868
Advertiser Internet Directory   871
In Memoriam   879
Sections Contacts Directory   881
AES Conventions and Conferences   888

FPO For the cover:

2005 September, Volume 53 Number 9

spine: 2005 September, Volume 53 Number 9