Effects of stage volume ratio on the acoustics of simulated concert halls

Abstract

This study proposes stage volume ratio as a new acoustic design factor for concert halls, and investigates the dependency of acoustic parameters of an auditorium on the stage volume through computer simulation. First, the ratio of the stage volume (Vo) to the total volume of a concert hall was defined as the stage volume ratio (Vo/V) through case studies of existing concert halls. It was verified using a simple model that the stage acoustic parameter STEarly and the auditorium acoustic parameters G, G80, and C80 decreased whereas reverberation time and early decay time increased with increasing stage volume ratio. Second, computer simulation was performed for nine existing concert halls while changing the stage volume ratio from −20 to 30 %. The result showed that the room acoustic parameters have the same pattern as suggested by the simple model. The stage volume ratio had a significant effect on the bass ratio and bass index. A comparison between the effects of the stage volume ratio and the sound absorption coefficient in nine concert halls found that the stage volume ratio contributed approximately 15 % to the reverberation and had a greater effect on the bass characteristics. These results verified that in the acoustic design of concert halls, the stage volume ratio proposed in this study is a critical design factor when determining the warmth of the auditorium acoustics. The evaluation data of this study could be used as a basis for acoustic design in the future.