The restoration of Châtel Guyon’s theatre is a compelling example of thermal cities small theatres which have resisted the Casino offers or their transformation into a cinema or a conference hall. The original design, drawn by the architect Le Voisvenel in 1902, would probably have a low slope audience and one or two levels of semicircle balconies to correspond with the lobby.

As for the room decoration, it follows the vertical height of the space with frame panel moldings, creating a consistent image with the frieze moldings and the central neo baroque ceiling. This particular decoration forms the originality of the theatre and reveals the necessity for the restoration and revaluation of the thermal ensemble.

However, the decor creates a very reverberant room which must be partially covered with absorbing surfaces. It is also necessary to propose an acoustic treatment for the sidewalls of the stalls.

Our next step was to launch a complete acoustical study including computer simulations so as to assess the necessary correction without compromising the existing décor but completing it.

The ceiling treatment consists of a significant variable in this study (secondary reflections on the balconies).