Required spatial resolution for late reverberation in a 3-dimensional loudspeaker array
The simulation and auralization of room acoustics can have numerous applications in interactive evaluation environments (e.g., for hearing aid development), psychoacoustic studies or simulation,rehabilitation, and computer games. The fast and perceptually plausible room acoustics simulator RAZR [Wendt et al., J. Audio Eng. Soc., 62, 11 (2014)] synthesizes binaural room impulse responses by using image sources for early reflections and a feedback delay network (FDN) for the late reverberation. For spatial auralization via headphones, HRTFs are used, and the late reverberant sound field is spatially sampled in twelve isotropic discrete directions. Here, the spatial rendering of RAZR was realized for a three-dimensional loudspeaker array in an anechoic chamber. It was assessed which spatial resolution is sufficient for the rendering of the late reverberation. Furthermore, a method was developed to account for different wall absorption coefficients resulting in an anisotropic late reverberant field. It was investigated for which room configurations and which spatial resolution of the late reverberation rendering differences are perceivable. Critical room conditions are elongated rooms (e.g., corridors), listener positions close to walls, and single highly absorbing walls. Listening tests were performed where subjects had to compare reverberated speech and impulse responses in various simulated rooms.