Norwich Theatre Royal (Great-Britain)
Clients and contractors share the same ambition both for renovation and construction of theatres, to obtain the best possible acoustics. "Every demand requires a specific response, emphasizes Isabelle Schmich, Manager of the Room and Complex Volume Acoustics cluster at CSTB in Grenoble. Depending on the case, we make recommendations, for example about the configuration of the rooms or the choice of materials. We are working on drawings and we are also carrying out acoustic simulations and model studies." We sometimes recommend installing the Carmen® system. With this patented system, an innovative acoustic technique designed by CSTB researchers, it is possible to overcome bad sound propagation affecting some concert halls. The principle is the use of active virtual walls composed of quasi-local reaction cells distributed on the walls and ceiling around the room. Each cell picks up and restores sound in real time as if it was naturally reflected, so that the distribution of sound, clarity or intelligibility of sound can be managed.
Before installing Carmen®, the number of seats installed, the volume of the room, the empty room reverberation time and the reverberation time required by the client have to be known. Drawings of the room are also essential to determine the distribution of volumes, the acoustic distribution and any defects or sharp edges in the architecture that could influence sound propagation. Finally, a "visual diagnostic" has to be made to confirm the initial conclusions.