Computational approaches to model the response of particular rooms (defined by complete geometrical specifications) are generally grouped into two categories:
The wave-based approaches generally require significantly more computational resources, though ray-tracing techniques can be quite demanding as well.
The image-source method is based on a ray tracing model for room reflections (assuming specular reflections from large, smooth surfaces). “Virtual sources” are determined at mirror image locations with respect to reflecting surfaces. Once the virtual sources are determined, propagation distances can be easily calculated from two- or three-dimensional Euclidean geometry. Note that path validity checks are necessary.
A “distributed” physical modeling approach to a reverberant space would allow for dynamic modifications of listener and source positions during an acoustic simulation.
However, a brute force acoustic simulation of a room response using three-dimensional physical modeling techniques would require nearly 150 million “mesh” grid points to simulate a room of only 4 x 4 x 3 meters at a sample rate of 50 kHz.
In addition, current three-dimensional modeling techniques are plagued by dispersion errors that would limit the quality of this approach. It is possible to use warping techniques to minimize the dispersion errors but this would significantly increase the already prohibitive computational burden.