Virtual Acoustics by Numerical Simulation

New emerging multimedia standards, like the MPEG-4 standard allow the creation of virtual or synthetic acoustical environments. To auralize an environment from its geometric description, simulation algorithms for acoustic wave propagation are required. The different methods used for computational modeling of room acoustics can be divided into three groups [1]: statistical models, ray-based models and wave-based models. Statistical models try to model the statistical properties of the sound intensity and are therefore not useful in our context. Ray-based models suppose that the sound behaves like optical rays. As a result the effects caused by the wave nature of sound, like diffraction, cannot be handled by these methods. Wave-based methods try to find numerical simulations for the wave equation. Because they use distributed parameter models, they are able to handle all relevant physical effects, namely wave propagation, reflection, transmission and diffraction. To meet the high simulation quality requirements of the proposed application, wave-based methods are the only ones suitable here. Among various other methods developed in the last two decades, we present here a direct method to computational acoustics, which leads from the partial differential equations to a state space description of the simulation algorithm.