A bi-modal model to simulate auditory expectation for reverberation time and direct-to-reverberant energy from visual feedback

Abstract

A bi-modal model is presented that predicts the psychophysical results of Valente and Braasch [Acustica, 2008]. The model simulates expectation of room-acoustical qualities due to visual cues. The visual part of the model estimates angles of incidence and delays of the first two side reflections of a given frontal sound source. To this end, a stereoscopic image is used to determine azimuth angles and distances for the two frontal room corners. The distance estimates are derived by using the angular differences between the left- and right-eye images of each corner. The model then calculates the room volume by reconstructing a rectangular room from these data, assuming a range of possibilities for the missing room coordinates. In a next step, logarithmic fits of volume to expected reverberation time and of volume to direct-to-reverberant energy ratio predict the expected value ranges for these two parameters. Using a feedback structure, the visually-derived acoustic parameters become input to an auditory Precedence-Effect model, where they are used to pre-adjust inhibition parameters for two acoustic side reflections. These inhibition parameters are consequently refined in the course of the analysis of the incoming sound. [Work supported by NSF #1229391/#1320059 and ERC FP7-ICT-2013-C-#618075.]