Abstract: A thermally and hygroscopically stable subsurface layer for supporting an outer (typically visible) surface of an acoustical panel. The subsurface layer comprises a thermally and hygroscopically stable composite, specifically a non-woven or woven fabric impregnated with binder and filler materials. The fabric provides exceptional resistance to thermal expansion and contraction, while the binder and filler materials are naturally very resistant to moisture changes. The result resists warping, cupping, or bowing in response to changes in ambient moisture or temperature, especially in situations in which the laminated surface and subsurface layers are perforated to allow sound to enter the interior or the panel and be absorbed by suitable materials within the panel.

Abstract: Acoustical materials of the type provided in panel form for purposes of controlling or adjusting the acoustics of an interior space, such as an auditorium or concert hall, conference room, etc., and commonly referred to as architectural acoustical panels or ceiling panels. A panel comprises multiple layers, such as a surface layer which faces the room or sound source, which in turn comprises wood veneer laminated to a supporting layer and defines a plurality of microperforations extending entirely through, the surface layer. An acoustical absorbing layer may be a wood wool material or, most preferably, high-density fiberglass having a particular orientation, along with a combination of a support material or ribbing, which may define a plurality of cells in which the fiberglass lies. A back support layer may be perforated or solid.