Patent ID: 8708097

Claim:
A panel including an air impermeable membrane layer and a layer having apertures therein, the membrane layer overlying the layer having apertures therein with the membrane layer forming a diaphragm at each location where the membrane layer traverses one of the apertures, each diaphragm being able to vibrate in response to sound waves incident on the membrane layer and thereby absorb at least some energy of the sound waves, the layer having apertures therein having a length and a width, at least some of the apertures being arranged in clusters which are spaced apart along the length and across the width of the layer having apertures therein, wherein each of said cluster is defined by a set of three or more apertures which are separated by a distance and a greatest distance between any two adjacent apertures within a particular one of said cluster is less than a distance between each aperture outside of said particular one of said clusters and each aperture within said particular one of said clusters, each aperture within each of said clusters having a length and a width, the apertures within each of said clusters being arranged to collectively provide each of said clusters with a length and width, the length and width of a particular one of said clusters being greater than the length and the width of each of the individual apertures within said particular one of said clusters, the panel having regions, each of said regions being defined by an outer periphery of one of said clusters and forming a resonance absorber which is able to vibrate in response to sound waves and thereby absorb at least some energy of the sound waves, wherein each resonance absorber is able to provide sound absorption at a frequency which is between a frequency of resonance of at least one of the diaphragms and a frequency of resonance of the panel as a whole.