Localization of virtual sound sources in realistic and complex scenes: how much do hearing aids alter localization?

Abstract

The human auditory system relies strongly on differences in time and intensity between the two ears to localize correctly a sound source. Bilateral or independent hearing aids distort this information. Van den Bogaert, et al. (2005) showed that, in an anechoic environment, sound localization is better without hearing aids than with. In this study, we investigated how hearing aids modify our localization ability in realistic conditions. With the idea in mind of extending the test situations to arbitrary acoustical environments, virtual acoustics were used as a tool for reproducing sound. The first experiment presented in this paper evaluates sound localization in noise and compares external playback through loudspeakers with the simulations. In a second experiment, we extended our system for virtual acoustics by simulating actual hearing aid algorithms as well. The algorithms implemented are a static beamformer, a monaural noise canceller and the omnidirectional situation, in which the microphone signal is fed directly to the system. The same test conditions as in experiment 1 were reproduced and hearing aid localization was compared to the unaided condition.