Overhead stage canopies in a coupled volume theatre: Effects on the sound energy distribution and on the secondary reverberation

Abstract

Nowadays, opera houses are often used for symphonic music, even though the intrinsic characteristics of these theatres are not suited for this purpose, due to their coupled volumes and high absorption of the fly tower. When symphonic music is performed in these halls an overhead stage canopy is often used to enhance the orchestral performance. In the present work, the effects of a canopy array in a coupled volume theatre were studied. The array canopy was designed and installed based on Geometric Acoustic (GA) simulations calibrated with in-situ measurements. Results showed peculiar effects on the sound energy distribution through space: the sound strength values depends on the “effective” volume of the theatre, varying with the sound source position. Moreover, when the stage is covered by the canopy array, the sound strength depends on the distance from the aperture instead of the distance from the sound source position. In other words, the decay curve is “tilt” by “effective volume” and “shifted” by the canopy array. Furthermore, the changes in sound behaviour due to the canopy array may be considered as a switch-off of the secondary reverberation effect.

Italian-Style Opera Houses: A Historical Review

“…It is well known that the presence or absence of draperies on the stage can influence significantly the sound behaviour at listeners' position [150,151]. Moreover, the sound source position in a coupled space can influence the sound energy decay [129,146,152]. The Ferrara-charter procedure states two positions of the sound source on the stage-the one in the fore-stage, the other one in the back stage-in order to 'average' the effects of coupling between the fly-tower and the cavea.…”

“…Moreover, a theoretical model for sound energy distribution in an opera house is needed. It must take into account the size of aperture, the coupling effect between the two sub-rooms [146,[167][168][169][170]-the fly tower and the main hall-and the sound source position [129]. Furthermore, due to the subjective relevance of the balance and listener envelopment, the SISO (single-input-single-output) model of sound strength could be extended.…”