Abstract:
A model for the determination of an acoustic field in a closed room with several sound sources is presented. In this model the sound source is divided into sound rays, which are followed in the room, with these characteristics: (1) The sound pressure and the particle speed are the working variables used, so that calculating the most important qualification parameters of a room is possible; (2) the ray emission from the source is done randomly; (3) the sound ray is represented by a cone including the corresponding solid angle; (4) the receiver is a dimensionless point; (5) the outputs obtained in the receiver have a statistical treatment; (6) ray diffusion on rough walls are considered, by means of a calculation based on the Markoff--Chain theory; and (7) obstacles are allowed in the room, and the diffraction over them is considered by a combination of the Helmholtz--Kirchhoff theorem and the Markoff--Chain method. The model was applied to the Lecture Theatre of the High Technical School of Industrial Engineering at Valencia, and the results that were obtained were compared with the measurements taken there. The experimental values were, in 90% of the cases, between those given by the model as probables.