An investigation of the modal characteristics of nonrectangular reverberation rooms

Abstract

The finite element method is used to study the modal characteristics of a class of reverberation rooms with parallel floors and ceilings. Special numerical procedures are developed to express acoustic finite element matrices as functions of room shape and to reduce the computational requirements for room evaluation. The modal distribution function proposed by Louden [M. M. Louden, Acustica 24, 101–104 (1971)] is used to evaluate room performance. Two studies of rooms with one nonparallel wall illustrate the typical influence of room shape on the modal distribution in the room. A global optimization is attempted for a room with five independent shape variables. A solution 40% better than the best rectangular reverberation room was found using approximately 450 000 room evaluations.