Orchestra shells: Acoustical and practical design considerations

Abstract

A hall or an outdoor facility is rarely used for a single type of artistic program. Often, it is necessary to design an orchestra shell that transforms theoretically a theatre or an opera house into a concert hall. The acoustical criteria for opera or concerts are quite different; the design of an orchestra shell that would create proper acoustical conditions on stage for the musicians and in the hall for the audience can be quite complex. The larger the hall and the proscenium opening, the harder it is to come up with an adequate solution. The major problems are the following: architecture and aesthetics, acoustical efficiency, ensemble conditions, acoustic response, diffusion, size, weight, transformation time, and storage. Some progress has been made over the last few years, but the problem remains complex. This paper will attempt to explain the design and construction process and will provide recent examples of small and large shells: Ravinia, Lille concert hall, Gradignan, Porto Teatro S. João, Opera Garnier in Paris, Staatsoper in Munich, and Serralves auditorium in Porto.