Sound Diffusion Design for a Rectangular Concert Hall Using a 1:25 Scale Model

Abstract

To adequately evaluate sound diffusion in a rectangular concert hall, acoustic verification results from physical scale models and computer simulations are compared in this study. In these two verification methods, the researchers implemented three cases: the concert hall was finished without sound diffusers; sound diffusers were installed in a large area all along the back wall of the stage, side walls of the third floor in the audience area, and back walls of the second and third floors in the audience area; sound diffusers were installed on the side walls of the first and second floor in the audience area near the stage and all along the front of the balcony. These cases were virtually simulated using a computer program, and for the physical models, hemisphere diffusers were installed on the scale models. The sound diffusion effects were evaluated through relative standard deviations (RSD) among the seats depending on the arrangement of the sound diffusers. The computer simulations revealed that the RSD differences for reverberation time (RT) and early decay time (EDT) based on the arrangement of sound diffusers were small. Analysis of the values measured from the scale models indicated that the RSD differences were large depending on the existence and locations of the sound diffusers. This indicates that scale models are required for sound diffusion evaluations of rectangular concert halls. Further, an analysis of the scale model reveals that sounds are diffused better when the sound diffusers are installed closer to the sound source.