A process for manufacturing an acoustical panel comprises mixing an aqueous slurry comprising water and at least about 90 wt. % of mineral wool, glass wool, or a combination of mineral wool and glass wool, the mineral wool, the glass wool, or the combination of mineral wool and glass wool having an average diameter of at least about 5 microns on a dry basis, to produce an acoustical panel having a NRC of about 0.80 to about 1.00 and a CAC of about 30 to about 50.