Perceptual evaluation of headphone auralization of rooms captured with spherical microphone arrays with respect to spaciousness and timbre.

Abstract

A listening experiment is presented in which subjects rated the perceived differences in terms of spaciousness and timbre between a headphone-based headtracked dummy head auralization of a sound source in different rooms and a headphone-based headtracked auralization of a spherical microphone array recording of the same scenario. The underlying auralizations were based on measured impulse responses to assure equal conditions. Rigid-sphere arrays with different amounts of microphones ranging from 50 to up to 1202 were emulated through sequential measurements, and spherical harmonics orders of up to 12 were tested. The results show that the array auralizations are partially indistinguishable from the direct dummy head auralization at a spherical harmonics order of 8 or higher if the virtual sound source is located at a lateral position. No significant reduction of the perceived differences with increasing order is observed for frontal virtual sound sources. In this case, small differences with respect to both spaciousness and timbre persist. The evaluation of lowpass-filtered stimuli shows that the perceived differences occur exclusively at higher frequencies and can therefore be attributed to spatial aliasing. The room had only a minor effect on the results.