1999 September, VOLUME 47 NUMBER 9

CONTENT

PAPERS

Creating Interactive Virtual Acoustic Environments
Lauri Savioja, Jyri Huopaniemi, Tapio Lokki, and Riitta Väänänen 675

The modeling techniques for the three major components of real-time auralization, namely the sound
source, the room acoustics, and the listener, are presented extensively by the authors. They have
developed a software system, DIVA, for producing virtual audio-visual performances in real time.
A wide range of future applications for this software is proposed, such as computer games,
multimedia, virtual-reality applications, and architectural acoustic designs.

ENGINEERING REPORTS

MATLAB Program for Loudspeaker Equalization and Crossover Design M. O. J. Hawksford 706

A digital design filter program has been written in the MATLAB environment. The filter design uses
time-domain impulse response data at its input and generates filter coefficients for both FIR and
IIR implementations. Comprehensive display options are incorporated in the software which include
minimum phase processing. Consideration is also given to designs for specular and diffuse
loudspeakers.

A Real-Time Speech­Music Discriminator
Ronald M. Aarts and Robert Toonen Dekkers 720

A unique real-time discriminator has been designed that automatically detects the differences
between speech and music signals and is not gender sensitive. Its operational reliability has been
tested on a series of modern languages as well as in various types of musical and instrumental
combinations. The system's authors state that their method is extremely reliable with virtually
zero false alarm probability.

The Use of Airborne Ultrasonics for Generating Audible Sound Beams F. Joseph Pompei 726

Audible sound is created from ultrasound sources that use the nonlinear characteristics of air. The
resulting sound from a wide-band parametric acoustical array is extremely directional and beamlike.
This field of acoustical activity is relatively new and the author has included a discussion of future
challenges to this area of ultrasound applications.

STANDARDS AND INFORMATION DOCUMENTS

DRAFT REVISED AES7-xxxx AES standard for the preservation and restoration of audio
recording -- Method of measuring recorded fluxivity of magnetic sound records at medium
wavelengths (insert)

DRAFT AES31-3-xxxx AES standard for network and file transfer of audio -- Audio-file
transfer and exchange -- Part 3: Simple project interchange (insert)

DRAFT AES3-1992 Amendment-4-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 732

IEEE 1394; archival transfers

FEATURES

Fundamentals of Modern Audio Measurement Richard C. Cabot 738

Updates and Corrections to the 1998/1999 International Sections Directory 772

DEPARTMENTS

Review of Acoustical Patents 735

News of the Sections 763

Sound Track 767

Upcoming Meetings 769

New Products and Developments 769

Available Literature 771

Membership Information 774

In Memorium 776

Sections Contacts Directory 778

AES Conventions and Conferences 784

In this issue...

Interactive Virtual
Acoustic Environments

Crossover and Equalizer Design

Speech­Music Discriminator

Audible Sound Using Ultrasonics

Features...

Fundamentals of Modern
Audio Measurement

FPOFor the cover:

Volume 47 Number 9 1999 September

spine:VOLUME 47, NO. 9 1999 SEPTEMBER