1998 April, VOLUME 46 NUMBER 4

CONTENT

Introduction David Meares 275

PAPERS

The Use of Subwoofers in the Context of Surround Sound Program Reproduction
Nick Zacharov, Søren Bech, and David Meares 276
Placement of subwoofers for enhancement of television multichannel sound in a domestic environment is noncritical for the reproduction of 5.1-channel audiovisual material below 85 Hz.

Subjective Appraisal of Loudspeaker Directivity for Multichannel Reproduction
Nick Zacharov 288
High-directivity loudspeakers in multichannel reproduction provide less excitation to the reproduction room boundaries. This results in fewer room reflections, so that essential directional cues are reproduced more faithfully.

Calibration of Relative Level Differences of a Domestic Multichannel Sound Reproduction System
Søren Bech 304
The type of calibration signals to set relative loudspeaker levels in a multichannel reproduction system must be evaluated with regard to immediate environmental factors. The listening room, program material, and reproduction system must be considered to establish a meaningful calibration level for domestic multichannel sound reproduction systems.

The Influence of Stereophonic Width on the Perceived Quality of an Audiovisual Presentation Using a Multichannel Sound System
Søren Bech 314
The spatial quality of reproduced sound for both audiovisual and audio-only program material increases with increasing stereophonic width and reproduction sound level. Independent of playback level and stereophonic width, spatial quality decreases as the listening position moves off center.

Program Origination of Five-Channel Surround Sound
D. G. Kirby, N. A. F. Cutmore, and J. A. Fletcher 323
Multichannel sound offers much improved performance over that of two-channel sound. Additional microphones for the surround channels contribute a worthwhile spatial quality improvement to the surround sound presentation.

Matrixed Surround Sound in an MPEG Digital World
D. J. Meares and G. Theile 331
The introduction of digital multichannel compressed sound service need not result in the loss of Dolby Stereo services. Inclusion of these options require using Dolby Stereo-capable MPEG encoders, which need a slightly higher bit rate than two-channel stereo for the same overall audio quality.

Dynamic Range Control (DRC) for Multichannel Audio Systems
Wolfgang Hoeg 336
A compatible dynamic range control system is proposed for multichannel transmission or storage in accordance with ITU-R and ISO/MPEG-2 standards to accommodate the domestic listener. Implemen- tation is achieved by inserting a control signal into the transmitted multichannel audio bit stream.

Dynamic Range Control in a Multichannel Environment
N. A. F. Cutmore 341
Generating a dynamic range control signal appears to be more complex for multichannel signals than for stereophonic programs. In this proposal there are more than one dynamic range control signals available to accommodate a variety of future multichannel audio program encoding needs.

STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News 348

AES-24 comments; tape flutter; digital audio measurements; sound-system modeling; Internet audio; connectors

DRAFT REVISED AES5-xxxx Draft revised AES Recommended Practice for Professional Digital Audio Applications Employing Pulse-Code Modulation - Preferred Sampling Frequencies (insert)

FEATURES
Microphone and Mixing Techniques for Multichannel Surround Sound
Francis Rumsey 354

DEPARTMENTS
Reviews of Acoustical Patents 352
News of the Sections 360
Sound Track 366
Upcoming Meetings 367
New Products and Developments 368
Available Literature 370
Membership Information 372
Audio Engineering Society Application Instructions 376
Sections Contacts Directory 379
AES Conventions and Conferences 384