| 2008 April, Volume 56 Number 4 |
CONTENTS
PAPERS
Adaptive Virtual Surround Sound Rendering System for an Arbitrary Listening Position
Sunmin Kim, Donggeon Kong, and Seongcheol Jang 243
A smart virtual reality presentation system, using only two loudspeakers, allows for a dynamically selected sweet spot that can be positioned at the arbitrary location of the listener. An efficient asymmetric crosstalk cancellation creates the needed filters to reposition the sweet spot; and a specialized remote control held by the listener allows the system to determine the angle and distance to the listener. Informal listening tests showed that the proposed approach can enhance the surround sound effect for television listening. Compared to conventional playback, listeners preferred this system at every location.
Efficient Audio Equalization Using Multirate Processing
Riitta Väänänen and Jarmo Hiipakka 255
The excessive computational burden of some specialized equalization requirements can be reduced by using multirate processing. Quadrature mirror filters split the audio signal into narrow bands that can be downsampled and then filtered with modest processing loads. The composite bands are then upsampled and reconstructed into a full-band signal. The main advantage of this approach is design flexibility since the filters in each band can be implemented independently of each other.
Spectral Impairment of Two-Dimensional Higher Order Ambisonics
Audun Solvang 267
When reproducing a two-dimensional higher order Ambisonic soundfield with a uniformly distributed loudspeaker array, there is a tradeoff that depends on the radius of the reproduction area, the order, and the wave number. For classical first-order Ambisonics, perfect reconstruction is possible in a tiny sweet spot, and filtering can be used with a larger number of loudspeakers. However, for a larger sweet spot, higher order Ambisonics must be used and the number of loudspeakers must be matched to the order because filter compensation is not possible. The number of loudspeakers is a tradeoff between spectral impairment at high frequencies and reproduction errors at low frequencies.
ENGINEERING REPORTS
Using a Steered-Response Power-Phase Transform to Optimize Speech Pickup in Reverberant Environments
Mingsian R. Bai and Pochang Ho 280
Using various signal processing technologies, a microphone system has been developed to enhance hands-free communications in automobiles. The steered microphone array functions as a highly directive beamforming spatial filter, thereby emphasizing the location of the selected talker. Experimental results demonstrate that a steered response power-phase transform algorithm is robust in reverberant and noisy environments.
STANDARDS AND INFORMATION DOCUMENTS
AES Standards Committee News 292
MPEG Surround in AES3; transfer technologies
FEATURES
33rd Conference Preview, Denver 294
Calendar 297
Program 298
Orchestrating Automotive Audio Francis Rumsey 303
DEPARTMENTS
News of the Sections 308
New Products and Developments 316
Sound Track 317
Upcoming Meetings 317
Membership Information 318
Advertiser Internet Directory 323
Sections Contacts Directory 328
AES Conventions and Conferences 336
FPO For the cover:
2008 April, Volume 56 Number 4
spine: 2008 April, Volume 56 Number 4