Analysis of sound fields in rooms using Bergeron's method

At the designing stage of an auditorium, e.g., a concert hall or theater, it is imporant to predict its acoustic field via a computer. A conventional prediction method based on geometrical acoustic theory gives only a macroview of the field, and an addirional scale model test is required for a further investigation. to overcome this problem, although a technology to treat the sound field in a room as a wave field has been considered, there have been few examples of hree-dimensional time-response solution of the sound field in a room because of the difficulty of handling a wide analytical region, ide frequency band, and complex boundary conditions. This paper examines the justification of application of Bergeron's method to three-dimensional sound field in a room. This paper also analyzes the correspondence between a three-dimensional equivalent-ciruit representation and the sound field, and examines the fundamental nature of a free sound field. Based on the results, a model of a simple rectangular room was considered, and its steady-state sound pressure distribution (which is a fundamental characteristic the field) and simulation of reverberation (transient phenomenon) were examined. All the successful results show the usefulness of the proposed method.