Psychoacoustic Characterization of Propagation Effects in Virtual Environments

Abstract

As sound propagation algorithms become faster and more accurate, the question arises as to whether the additional efforts to improve fidelity actually offer perceptual benefits over existing techniques. Could environmental sound effects go the way of music, where lower-fidelity compressed versions are actually favored by listeners? Here we address this issue with two acoustic phenomena that are known to have perceptual effects on humans and that, accordingly, might be expected to heighten their experience with simulated environments. We present two studies comparing listeners’ perceptual response to both accurate and approximate algorithms simulating two key acoustic effects: diffraction and reverberation. For each effect, we evaluate whether increased numerical accuracy of a propagation algorithm translates into increased perceptual differentiation in interactive virtual environments. Our results suggest that auditory perception does benefit from the increased accuracy, with subjects showing better perceptual differentiation when experiencing the more accurate rendering method: the diffraction experiment shows a more linearly decaying sound field (with respect to the diffraction angle) for the accurate diffraction method, whereas the reverberation experiment shows that more accurate reverberation, after modest user experience, results in near-logarithmic response to increasing room volume.