Binaural room simulation based on an image source model with addition of statistical methods to include the diffuse sound scattering of walls and to predict the reverberant tail

Abstract In order to predict the aural impression of the listening conditions which is to be expected at the various seats of a room (e.g. a concert hall) in particular when this is still in the stage of design, binaural room impulse responses for given source and receiver positions must be determined. This paper describes an approach to add a diffuse background signal to the result of an image source method, in which only the specular parts of the reflections are considered. The missing diffusely scattered energies are handled by a method based on the result of a sound particle tracing procedure with a low time resolution of a few milliseconds. This combined method is used to predict the direct sound and the early reflections of the binaural room impulse response. The reverberant part and the diffuse background signal are determined with methods which require only little room-specific information and obtain the remaining data statistically. For the late part of the binaural response a simplified simulation method is presented, that is based on the frequency-dependent reverberation time. Furthermore, the paper discusses the connection of two parts of a room impulse response, which are calculated by means of different methods.