ABSTRACT
This chapter chooses a quite different approach, namely a substantial simplification of the propagation laws. This is achieved by considering the limiting case of vanishingly small wavelengths, that is, of very high frequencies. In geometrical room acoustics, the concept of sound waves is replaced by the concept of sound rays. The latter is an idealization just as much as the plane wave. Any typical wave effects such as diffraction are neglected in geometrical room acoustics, since propagation in straight lines is its main postulate. It is self-evident that geometrical room acoustics can reflect only a partial aspect of the acoustical phenomena occurring in a room. This aspect is, however, of great importance because of its conceptual simplicity and the ease of practical sound field computations. For a given enclosure and sound source position, the image sources can be constructed without referring to a particular sound path.
