Patent ID: 7467498

Claim:
A tensioned structure comprising: a support structure; and an acoustic absorbing sheet of flexible polymer material having a thickness of less than half a millimeter and tensioned relative to the support structure; the sheet of material including microprojections having a height of 100 μm or less; wherein the sheet of material presents an acoustic absorption coefficient which is higher than that of the same material without said microprojections; wherein said material is provided with microperforations having openings smaller than four-tenths of a millimeter wherein said microperforations are disposed between the microprojections; wherein the microperforations are disposed at the nodes of a pattern; wherein the microperforations are disposed at the nodes of a pattern identical to the pattern of the microprojections and offset relative thereto; wherein the density of microperforations lies in the range 2 to 60 per square centimeter; wherein the sheet of material is selected from the group consisting of plastified polyvinyl chlorides, vinylidene chlorides, copolymers of vinyl chloride and vinylidene chloride, and combinations thereof; and wherein the area occupied by the microprojections lies in the range 0.5% to 10% of the area of said sheet.