1998 December, VOLUME 46 NUMBER 12

CONTENT

PAPERS
Two Decades of Sound Diffusor Design and Development, Part 2: Prediction, Measurement, and Characterization
Peter D'Antonio and Trevor Cox 1075
Methods for measuring and predicting the scattered polar sound distribution by using boundary-element methods and maximum-length-sequence stimuli are reviewed in this, the second part of a paper on diffusors. An extensive list of references is included as well as a glossary of acoustical terms. The supporting illustrations give the reader a broad outline of the comprehensive methods used to make these measurements of diffusor performance.

Frequency-Domain Equalization of Audio Systems Using Digital Filters, Part 2: Examples of Equalization
Alexander Potchinkov 1092
Numerical examples of digital-domain equalizers are presented in this, the second half of a two-paper presentation. The author has shown the advantages that accrue from equalization by digital filter means. Some related subjects are reviewed which include efficient multirate filter realization, parametric modeling, and the comparison of recursive and nonrecursive digital filters.

Orthogonal Sequence Modulated Phase Reflection Gratings for Wide-Band Diffusion
James A. S. Angus and Claire I. McManmon 1109
A technique, which uses two basic quadratic residue diffusors of different lengths, can remove the lobe narrowing that normally occurs when two diffusors are concatenated. An extended frequency performance range and a smoother diffusion response are achieved using the authors' composite design criteria. By employing these composite design sequences, the diffusion performance approaches that of a single sequence diffusor.

ENGINEERING REPORTS
Comparison of Two Methods for Measurement of Horn Input Impedance
Hans Schurer, Peter Annema, Hans-Elias de Bree, Cornelis H. Slump, and Otto E. Herrmann 1119
After comparing the acoustic horn impedance by two discrete measurement methods, the authors have concluded that horn impedance measurement is performed faster, easier, and more accurately by direct measurement using a microflown. It is shown that this is a valuable tool by which horns and other acoustical structures can be approximated and that their parameters can be tuned easily to obtain correspondence between measurement and model.

STANDARDS AND INFORMATION DOCUMENTS
DRAFT REVISED AES24-1-xxxx AES Standard for sound system control ­ Application protocol for controlling and monitoring audio devices via digital data networks ­ Part 1: Principles, formats, and basic procedures (insert)
AES Standards Committee News 1126
Internet audio quality; forensic audio; loudspeaker specification; 96 kHz digital; audio file format

FEATURES

AES 15th International Conference Report, Copenhagen, Denmark 1134
1998/1999 AES International Sections Directory 1142
Call for Nominations for Awards 1171
Call for Nominations for Board of Governors 1172
AES 9th Tokyo Regional Convention, Call for Papers 1176
AES 17th International Conference, Florence, Italy, Call for Papers 1178
AES 107th Convention, New York, Call for Papers 1180
Bylaws: Audio Engineering Society, Inc. 1182
Index to Volume 46 1186

DEPARTMENTS

News of the Sections 1164
Sound Track 1168
New Products and Developments 1169
Upcoming Meetings 1169
Available Literature 1170
Membership Information 1173
In Memoriam 1175
Audio Engineering Society Membership Application Instructions 1197
AES Conventions and Conferences 1200