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VSPS :: Virtual Sound Positioning System
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A Project by ...Markus Noisternig, noisternig [at] iem.at Piotr Majdak, piotr [at] majdak.com (C) 2001 IEM, Graz ContributorsRobert Höldrich, hoeldrich [at] iem.at
Contact detailsInstitute of Electronic Music and Acoustics (IEM) Inffeldgasse 10/3, 8010 Graz, Austria email :: noisternig [at] iem.at phone :: +43.316.389.3681 mobile:: +43.664.5301110 |
Abstract
Convincing sound reproduction via headphones requires filtering of virtual sound sourc signals with head related transfer functions (HRTFs). Letter describe the signal differences at the two ear drums as a function of the direction of arrival. Regarding hearing in natural sound fields humans are able to improve source localization capabilities due to small head movements. To benefit from this phenomenon in virtual reality (VR) applications, head tracking has to be incorporated. This requires the implementation of a time-varying binaural sound reproduction system, yielding the problem of high-quality time-varying interpolation between different HRTFs. The proposed method solves this problem by a virtual Ambisonic approach that results in time-invariant filters. The influence of the head position is taken into account with a cheap (in terms of signal processing) time-variant rotation matrix in the Ambisonic domain.
A prototype version of this binaural sound reproduction system has been implemented on a Unix machine running jMax and Pure Data (pd) - two real-time sound processing tools originiating in the computer music community - and has been proven to yield high quality binaural signals with reasonable computational effort.
The aim of this project was to improve the overall system latency by (a hand coded) implementation on a DSP.