Amphithéâtre Cogeco Trois-Rivières, Quebec

Soffit

The underside of the exterior roof above the public is made of custom prefabricated red painted steel panels measuring 806 x 1884 mm with a 51 mm fold on four sides forming a casing for the acoustical insulation. In the panels above the public where sound is transmitted, ROCKWOOL ROCKBOARD® 80 was used with a density of 128 kg/m³ required by the acoustician to absorb sound energy. For the panels located at the back of the stage, ROCKWOOL AFB® with a density of 45 kg/m³ was used in the casings for aesthetic purposes to prevent a see-through effect revealing the structure of the roof. Two metal wires were attached at the back of the panels to cross each other and hold tight the ROCKWOOLTM insulation against the strong winds brushing against the panels. After a first season of operation, no acoustical problems were reported.

ROCKWOOL products were chosen for fire safety requirements, for their resistance to water and moisture when used outdoors in harsh and moist environments and for acoustical purposes because of their high density and thus capacity to absorb sound energy. 

The challenge was to have an absorptive and porous material that could absorb the energy of the sound and withstand climatic conditions ranging from 30°C to -30°C, with high humidity rates due to two major rivers. ROCKWOOL stone wool insulation was used in the projectfor thermal insulation where walls had to be composed of non-combustible material and for acoustical purposes to absorb sound emitted from the stage and loudspeakers.

For acoustical applications, different types of perforated sheet metal were used to clad and protect the rock wool. The perforations had to be greater than 50% of the panel surface in order to let sound through and prevent reflections. The stone wool panels, visible through theperforated metal panels, were covered with a black fabric for aesthetic purposes.