Abstract: A rigid, self-supporting, acoustical mineral fiberboard comprising a mixture of about 50 to 70 weight percent of mineral fibers, 15 to 35 weight percent of perlite, 1 to 10 weight percent of cellulosic fibers, and 4 to 15 weight percent of a binder with the proviso that the board forming solids do not include any clay filler. A pattern is formed on the fiberboard after the fiberboard has been dried.

Abstract: A method of producing an acoustical mineral fiberboard comprising(a) forming an aqueous slurry of mineral fiber-containing solids suitable for forming an acoustical board, the solids content of the slurry being sufficiently high to bring about predominant formation of nodules of mineral fiber throughout the slurry upon mixing of the slurry;(b) mixing the slurry to form the nodules of mineral fibers;(c) dewatering the slurry to form a wet felt;(d) drying the wet felt; and(e) texturing one surface of the dried felt without mechanically punching holes in the surface.