Abstract: Acoustic energy is absorbed from a moving fluid by passing the fluid, which is typically a gas, over a surface covered with a multiplicity of fibers or filaments, each filament having one end attached directly or indirectly to the surface and its other end free and extending into the fluid stream. Automobile or marine mufflers or silencers effective in reducing or eliminating objectionable noise, but with only nominal back pressure, are disclosed.

Abstract: Acoustic energy is absorbed from a moving fluid by passing the fluid, which is typically a gas, over a surface covered with a multiplicity of loops of fibers or filaments, each loop having one portion thereof fixed to a suitable backing material, the backing material attached directly or indirectly to a conduit or the like and the other free portions extending into the moving fluid stream. Automobile mufflers or silencers effective in reducing or eliminating objectionable noise, but with at most only nominal back pressure, are disclosed.

Abstract: Acoustic energy is absorbed from a moving fluid by passing the fluid, which is typically a gas, through a tube of closely-woven material defining a gas passage, the tube of material being in contact with a surface covered with a multiplicity of fibers or filaments, each filament having one end attached directly or indirectly to the surface. Automobile or marine mufflers or silencers effective in reducing or eliminating objectionable noise, but with only nominal back pressure, are disclosed.

Abstract: Acoustic energy is absorbed from a moving fluid by passing the fluid, which is typically a gas, through a liner comprising a closely woven textile-like material which serves as an acoustically transmitting inner lining. Anchored either directly or indirectly to the acoustically transmitting inner liner is a sound absorbing material the surface of which is covered with a multiplicity of fibers or filaments, each filament having one end attached directly or indirectly to the surface and its outer end free and contacting the inner wall of a casing in which the tube and sound absorbing material are contained. Automobile or marine mufflers or silencers effective in reducing or eliminating objectionable noise, but with only nominal back pressure, are disclosed.