Sound radiation from stage in theatres of Cesenatico and Longiano

The role of the stage in horse-shaped italian theatres is a long debated topic. If professional musicians have no doubts on its importance, an univocal quantification of the contribution of the stage has not been identified yet. At the beginning of last century Sabine pointed out that, in order to predict the sound field in a room, the acoustic properties of the boundary cannot be determined only by its surface materials, but also its construction must be taken into account. Despite his suggestion, many studies in architectural acoustics have assumed rigid boundaries [4]. Among the boundary elements, one of the most interesting acoustic condition is connected to the stage fl oor; musical instruments are very close to the floor, and often mechanically coupled with it [5]. The contribution of the stage to the sound field of a hall has been analyzed both theoretically [3, 4, 5] and by means of numerical models and experimental measurements [6, 7, 8]. The structure of the stage - back cavities, ribs, joists or plates - was proved to affect its acoustic properties, but literature has not provided yet definitive arguments in support. This paper therefore investigates the role of the stage in the propagation of sound in enclosed spaces.