VOLUME 48 NUMBER 6 2000 JUNE

CONTENT

PAPERS

Revisiting Algorithms for Predicting the Articulation Loss of Consonants ALcons
Sylvio R. Bistafa and John S. Bradley 531

Algorithms proposed for predicting speech intelligibility that are based on articulation loss of consonants (ALcons) are examined. A simple algorithm, the architectural form of the Peutz equation, is discussed and re-derived using a system to further develop empirical equation forms. It is shown that the speech transmission index (STI) and the useful-to-detrimental sound ratio (U50) speech intelligibility predictions are highly correlated with each other in rooms that have diffuse sound fields and ideal exponential decays. The ALcons algorithms, however, have a tendency to under-predict speech intelligibility as the signal-to-noise ratio decreases.

ENGINEERING REPORTS

Interactions in a Multiple-Voice-Coil Digital Loudspeaker
Yaxiong Huang, Simon C. Busbridge, and Peter A. Fryer 545

Motional impedance and mutual coupling in a multiple-coil digital loudspeaker system increase the effective impedance of an individual coil relative to its binary weighting in a seven-bit digital constant-current driver configuration. This places an unreasonably high demand on the output impedance of the constant-current driver unless the loudspeaker's damping is controlled. A shorted turn voice coil can achieve this damping most effectively.

Development of the Wireless "Communications EarPlug" for Application in Military Aviation
Sander J. van Wijngaarden, Evert Agterhuis, and Herman J. M. Steeneken 553

Earplugs fitted with integrated miniature speech transducers have been developed specifically for use in high ambient noise level aircraft communications. The earplugs provide isolation from the local noise, while the miniature transducers provide a reliable intercommunication path for the user. The system's utility is further enhanced by integrating it with a wireless intercommunications interface, free of any cord connections to the aircraft's system.

Electrically Manifested Distortions of Condenser Microphones in Audio Frequency Circuits
Holger Pastillé 559

Distortions originate in condenser microphones from several sources: those which are attributable to the microphone's mechanical and acoustic functions and those which arise from their associated electrical circuitry. An analysis of the electrical design distortion contributions indicate that they are relatively minor in modern condenser microphones which have input resistances on the order of 20 G?. The distortions of acoustical and mechanical origin contribute more to the overall condenser microphone's distortion output than does the electrical circuit's configuration.

STANDARDS AND INFORMATION DOCUMENTS

AES41-2000 AES standard for digital audio - Recoding data set for audio bit-rate reduction 564

AES Standards Committee News Call for comment on revised AES26 audio polarity standard; digitally interfaced microphones; microphone specifications 584

FEATURES

High-Quality Multichannel Audio Coding: Trends and Challenges
Marina Bosi 588

DEPARTMENTS

News of the Sections 596

Sound Track 600

Upcoming Meetings 601

New Products and Developments 602

Available Literature 605

Membership Information 606

Advertiser Internet Directory 607

Audio Engineering Society Membership Application Instructions 610

AES Special Publications 613

Sections Contacts Directory 618

AES Conventions and Conferences 624

FPOFor the cover:

VOLUME 48 NUMBER 6 2000 JUNE

spine:VOLUME 48 NUMBER 6 2000 JUNE