Abstract: The disclosure provides basemats for fibrous panels, including a mineral wool present in an amount of at least about 60 wt %, based on the total weight of the basemat, a mineral filler, a cellulose present in an amount of about 1 wt % to about 3 wt %, based on the total weight of the basemat, and a binder. The basemat has a backing side and a facing side. Also provided are fibrous panels including the basemat of the disclosure and a porous veil.

Abstract: An acoustical panel construction useful as a suspended ceiling tile having a rectangular shape bounded by edges and establishing a face area comprising at least one corrugated layer or layers of a total thickness, the layer or layers having a multitude of parallel flutes extending across an expanse of the rectangular shape substantially from one edge of the panel to an opposite edge, the flutes being formed by walls of the layer or layers and being of known volume, a series of apertures each of known area through the wall or walls of the flutes communicating with the atmosphere at the face, the aperture area, flute cavity volume associated with an aperture, and the total thickness of the corrugated layers associated with an aperture being arranged to produce a maximum absorption frequency between 200 and 2,000 Hz.