On the robustness of upper limits for circular auditory motion perception

Abstract

We developed a new rendering system that consists of a image-source reflection model followed by a two-step strategy for modeling moving phantom sound sources (combining a physical propagation model and a spatialization method). This rendering system was used for simulations of pressure signals and acoustical localization cues, and for stimulus generation. We report three perceptual experiments measuring the upper limits, defined as auditory velocity thresholds beyond which listeners are no longer able to perceptually, resolve a smooth circular trajectory. These thresholds were measured in different reverberation conditions using white noise, band-limited white noise and band-limited white noise with a pure tone. Experiment 1 took place in a hemi-anechoic room and compared two conditions: dry and with simulated first-order reflections. In Experiment 2 we compare the thresholds measured in the hemi-anechoic room (dry and simulated second-order reflections) and in a reverberant room using two different loudspeaker configurations. Experiment 3 investigated the effect of audio source type in the dry condition at high velocities. No significant effects were observed among reverberation conditions, loudspeaker configurations and audio source type, suggesting that the upper limit is robust against reverberation.