Abstract: Disclosed is a multi-layered, substantially rigid and self-supporting acoustical panel. Preferably, the panel includes an acoustically absorbent semi-rigid core having a substantially continuous interior porosity. The panel also includes an acoustically permeable face layer applied to a first face of the core, wherein the face layer is adapted to allow acoustical energy to pass through the face layer and into the acoustically absorbent core. The panel also includes a flame-retardant, calendered paper backing adapted to be applied to the core. According to the present invention, the panel may also include a flame-retardant adhesive adapted to attach the calendered, flame-retardant paper backing to the core.