A study of coupled volumes in opera houses during restorations

In an opera house the main hall and the stagehouse can be regarded as a typical example of acoustically coupled volumes. In this case the coupling is regulated by the proscenium opening. As a consequence the modifications in the stagehouse can have an significant impact on the hall. In particular an excess of reverberation is to be expected if the stage set is particularly acoustically light or, even worse, if the volume of the tower is increased for some reason. In this respect several technical and logistic requirements imply an increase of the stagehouse volume when theatres are refurbished. This seldom happens especially in the case of historical opera houses to optimize the change and storage of modern settings. In order to study the coupled the gathering of suitable experimental data for arranging a reliable calculation model requires special efforts. In the present work dedicated acoustical measurements are presented to qualify the impact on the hall of the modifications to be implemented in the stagehouse of an historical opera house, the Teatro "Zandonai" in Rovereto, Italy.