Modeling binaural receivers in finite difference simulation of room acoustics

Abstract

Binaural room impulse responses are important for auralisation as well as for objective research in room acoustics. In geometrical room simulation methods, obtaining such responses is easily achieved by convolving each computed reflection tap with a corresponding pre-measured angle-dependent head-related impulse response. Unfortunately, employing such an approach in wave based methods is challenging due to temporal overlap of room reflections in the calculated response. One alternative is to physically embed a listener geometry in the grid. Whilst this method is straightforward, it requires voxelization of a geometrically-complex object. Furthermore, with non-conformal boundary conditions, the voxelized geometry is sample-rate dependent, meaning that numerical consistency may become compromised. In this paper we discuss the merits and drawbacks of embedding different listener geometries in the grid, ranging from a simple rigid sphere to a fully featured laser-scan of a Kemar mannikin. Results are analysed in terms of generated auditory cues, and are discussed in light of room acoustics modelling using the FDTD method.