Real-time virtual room acoustic simulation

Abstract

A realistic virtual room acoustic simulation has been implemented on a PC-based computer in near real-time. Room acoustics are calculated by the image source method using realistic absorption coefficients for a variety of realistic surfaces and programmed in MATLAB. The resulting impulse response filters are then applied in near real-time using fast convolution DSP techniques using data being read from a CD-ROM. The system was implemented in a virtual acoustic room facility. Optimizations have been performed to retain the realistic virtual room effect while minimizing computations through limited psycho-acoustic testing. In general, realistic anechoic to reverberant virtual rooms have been re-created with six 8192 coefficient filters. To provide realistic simulations, special care must be taken to accurately reproduce the low frequency acoustics. Since the virtual room acoustic facility was not totally anechoic (as are most anechoic chambers), inverse filters were applied to compensate for over-amplified acoustics at frequencies below 350 Hz.