Acoustical design of stages with large plane surfaces in rectangular recital halls

Effects of architectural features on stage acoustics for rectangular recital halls were evaluated based on acoustical simulations using Odeon 4.01 software. Variables included volume, splaying angle of perimeters, proportion, location and orientation of the performer, and detached reflectors. All surfaces were plane and relatively large. As a result, a 920-m3 wedge-shaped stage yielded a −12-dB early-to-direct energy ratio (ED80) and early support (STearly) as suggested by Gade. Besides reducing stage volume, early energy was enhanced by reducing the splay of stage envelope, reducing stage width, moving the source towards the back of the stage, and placing detached reflectors. For late energies the shape played a more important role than did the volume. No echo was found unless a trumpet source was used. The results provided alternative ways to control on-stage acoustics in recital halls.