Acoustic evolution of ancient Greek and Roman theatres

In this investigation the acoustic properties of ancient performance spaces for Greek and Roman drama were studied, from the viewpoint of material and design evolution. The paper first reviews the theatre evolution in antiquity. Following a systematic examination of computer simulation methodology for ancient Greek and Roman theatres, it then presents the results of a series of acoustic simulations in six typical theatre forms, using a beam-tracing program. Particular attention is paid to the scattering and diffraction from seat risers, which are important in outdoors theatres. Acoustic indices considered include sound pressure level, reverberation time and speech transmission index. The results show that in the evolution of ancient Greek and Roman theatres, changes in materials and theatre design generally resulted in acoustic improvements - the reverberation time had been increased and the sound level had been enhanced. Since the exact material characteristics are unknown, possible variations in acoustic performances are discussed based on simulations using a range of boundary absorption and scattering coefficients. (C) 2007 Elsevier Ltd, All rights reserved.