|2007 September, Volume 55 Number 9|
Perceptual Enhancement of Wavefield Synthesis by Stereophonic Means
Helmut Wittek, Francis Rumsey, and Günther Theile 723
Systems designed to accurately reconstruct soundfields in real spaces contain compromises that often result in error in perceived localization and sound color timbre. Wavefield synthesis is such an example. A new technique, called optimized phantom source imaging (OPSI), is designed to avoid spatial aliasing and the corresponding coloration of virtual sources. By combining low-frequency wavefield synthesis with conventional stereo, the proposed system improves the perceived sound color. This somewhat surprising result led to the hypothesis that a decoloration process exists in the model for stereo reproduction.
A Perceptual Approach for Interaural Transfer Function Calculations Based on Wiener Filtering
Kwuen-Yieng Ou and Mingsian R. Bai 752
In order to reduce the quantity of data needed to represent head-related impulse responses by as much as 40%, a perceptual approach uses the ipsilateral response as the basis for the contralateral response. Errors at high frequencies are masked, and non-audible components are eliminated. Objective analysis and a subjective listening test validated the proposed technique for three-dimensional sound generation. No significant errors were found in either azimuth or elevation.
Evaluation of Weighted Principal-Component Analysis Matching for Wavetable Synthesis
Simon Wun and Andrew Horner 762
Synthesizing musical instrument tones using wavetables is limited by the quality of the tables. Principal- component analysis (PCA), which uses spectral correlation to automatically create such tables, is efficient but usually does not adequately model sound in low-amplitude frames and with weak harmonics. By normalizing the signal before analysis, the weighted PCA method reduces spectral errors. Although PCA gives an analytic solution, none of the methods that were evaluated were optimum in all cases.
Audibility of a CD-Standard A/D/A Loop Inserted into High-Resolution Audio Playback
E. Brad Meyer and David R. Moran 775
Conventional wisdom asserts that the wider bandwidth and dynamic range of SACD and DVD-A make them of audibly higher quality than the CD format. A carefully controlled double-blind test with many experienced listeners showed no ability to hear any differences between formats. High-resolution audio discs were still judged to be of superior quality because sound engineers have more freedom to make them that way. There is no evidence that perceived quality has anything to do with additional resolution or bandwidth.
STANDARDS AND INFORMATION DOCUMENTS
AES Standards Committee News 780
Standards participation; audio applications using IEEE 1394; transfer technologies; microphone measurement and characterization; grounding and EMC practices
Auditory Displays 784
124th Convention, Amsterdam, Call for Papers 807
News of the Sections 791
Upcoming Meetings 796
Sound Track 797
New Products and Developments 798
Available Literature 799
Membership Information 801
Advertiser Internet Directory 805
In Memoriam 806
Sections Contacts Directory 808
AES Conventions and Conferences 816
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2007 September, Volume 55 Number 9
spine: 2007 September, Volume 55 Number 9