Linearizing Auditory Distance Estimates by Means of Virtual Acoustics

Auditory distance estimates are not linearly related to physical distances: people tend to overestimate close physical distances, and underestimate far distances. We have modeled a virtual listening environment whose objective is to provide a linear relationship between perceived and physical distance. The simulated environment consists of a trapezoidal membrane with specific absorbing properties at the boundaries. A physics-based model simulates acoustic wave propagation in this virtual space and provides auditory distance cues, namely intensity and direct-to-reverberant energy ratio. Simulations predict the linearity of the psychophysical function relating physical distance to perceived distance, computed from Bronkhorst and Houtgast's model. A listening experiment, involving eleven subjects and using a procedure inspired by the MUSHRA test, shows that the individual psychophysical functions are well described by a linear fit. This promising result suggests that the present virtual environment is a potential tool for providing a direct mapping between perceived and physical distance in auditory interfaces. In addition, the procedure was validated by retesting the same stimuli with the magnitude estimation method as well as reproducing the modified version of the MUSHRA test on a different simulated environment geometry.