2005 May, Volume 53 Number 5

CONTENT

PAPERS

Effect of Noise and Transducer Variability on the Performance of Circular Microphone Arrays
M. A. Poletti   371
As a low-cost alternative for three-dimensional microphone arrays, circular arrays are appropriate for analyzing room acoustics, recording live sound fields, and providing teleconferencing applications. The ideal performance of such arrays is limited by additive noise and transducer variability. These two effects are quantitatively examined for the simple case of incident plane waves. The effective signal-to-noise ratio depends on the frequency, the area of the array, and the density of microphones. Variations in phase among microphones produce high-order polar response errors at low frequencies.

The Active Listening Room: A Novel Approach to Early Reflection Manipulation in Critical Listening Rooms
Amber Naqvi and Francis Rumsey   385
Rather than trying to change the natural acoustics of a space, adding active panels and loudspeakers creates an active listening area within an existing space. Simulations using a computer-based acoustic design package determine the required parameters for creating the target space. This approach is more flexible than standardized reference listening rooms. In effect, the acoustics of a small region within a large space is being controlled.

Audible Noise Suppression with a Real-Time Broad-Band and Superdirective Microphone Array
Jose-Luis Sanchez-Bote, Joaquin Gonzalez-Rodriguez, and Javier Ortega-Garcia   403
By extending algorithms used for noise suppression from a single microphone to a 15-microphone nested linear array, extra spatial information then contributes additional noise reduction. This extra information

ENGINEERING REPORTS

Low-DC-Resistance, Low-Frequency Loudspeaker Enclosures
Carlo Zuccatti   419
By using loudspeaker drives with low voice-coil resistance, the sensitivity near resonance can be significantly increased. However at frequencies far from resonances, an additional passive filter provides safe impedance to the amplifier. The combination improves the sensitivity and power output in low-frequency enclosures. This approach has an extra degree of freedom not normally found with such enclosures.

STANDARDS AND INFORMATION DOCUMENTS

AES Standards Committee News   429
Shielding; high-resolution multichannel audio interconnection (HRMAI); metadata

FEATURES

26th Conference Preview, Denver   434
   Calendar   436
   Program   438
   Registration Form   442
Measuring and Predicting Perceived Audio Quality   443

DEPARTMENTS

Reviews of Acoustical Patents   432
News of the Sections   449
Upcoming Meetings   454
Sound Track   455
New Products and Developments   456
Available Literature   457
Membership Information   459
Advertiser Internet Directory   461
Sections Contacts Directory   465
AES Conventions and Conferences   472

FPO For the cover:

2005 May, Volume 53 Number 5

spine: 2005 May, Volume 53 Number 5