Apparatus for absorbing sound

Abstract

A tunable sound absorber including a fibrous batt having a plurality of fibers and a film coupled to the surface of the fibrous batt, where the fibers penetrate the film to create perforations, and where the perforations transfer sound energy to the fibrous batt and the sound energy is absorbed by the fibrous batt.

We claim:  
     
         1 . A sound absorber, comprising: 
 a fibrous batt having a plurality of fibers; and    a film coupled to a first surface of the fibrous batt, wherein a number of the plurality of fibers extend through the film, whereby a porosity in the film is created to permit sound energy to be conducted through the film into the fibrous batt.    
     
     
         2 . The sound absorber of  claim 1 , wherein the porosity can be varied to change the air flow resistance of the sound absorber to tune the sound absorber to absorb sound in specific frequencies.  
     
     
         3 . The sound absorber of  claim 2 , wherein the porosity is varied by the application of heat to the tunable sound absorber.  
     
     
         4 . The sound absorber of  claim 2 , wherein the porosity is varied by pressure applied to the film and the fibrous batt, whereby the pressure forces the fibers through the film.  
     
     
         5 . The sound absorber of  claim 2 , wherein the sound absorber can be tuned to match a particular absorption coefficient versus frequency curve.  
     
     
         6 . The sound absorber of  claim 1 , wherein the fibrous batt includes polymeric fibers.  
     
     
         7 . The sound absorber of  claim 6 , wherein the fibrous batt includes polyethylene terepthalate fibers.  
     
     
         8 . The sound absorber of  claim 1 , wherein the fibrous batt includes natural fibers.  
     
     
         9 . The sound absorber of  claim 1 , wherein the film includes polyester  
     
     
         10 . The sound absorber of  claim 1 , wherein the film is thermoformable.  
     
     
         11 . The sound absorber of  claim 1 , wherein a second film is coupled to a second surface of the fibrous batt.  
     
     
         12 . The sound absorber of  claim 1 , wherein the porosity is provided by perforations.  
     
     
         13 . The sound absorber of  claim 1 , wherein the porosity is provided by microruptures.  
     
     
         14 . The sound absorber of  claim 1 , wherein the porosity is provided by holes.  
     
     
         15 . A sound absorber comprising: 
 a matting of fibers; and    a film bonded to the matting, the film including a plurality of perforations having one or more of the fibers extending therethrough.    
     
     
         16 . The sound absorber of  claim 15 , wherein the matting of fibers converts sound energy into kinetic energy.  
     
     
         17 . The sound absorber of  claim 16 , wherein the film traps incident sound energy in the matting of fibers, whereby the sound energy is continuously reflected and attenuated within the matting of fibers.  
     
     
         18 . The sound absorber of  claim 15 , wherein the matting of fibers and the film are comprised of a similar polymeric material, whereby the sound absorber is recyclable.  
     
     
         19 . The sound absorber of  claim 15 , wherein the film is thermoformable.  
     
     
         20 . The sound absorber of  claim 15 , wherein the fibers are polymeric fibers.  
     
     
         21 . The sound absorber of  claim 15 , wherein the matting includes natural fibers.  
     
     
         22 . The sound absorber of  claim 15 , wherein the film includes a polymeric material.  
     
     
         23 . The sound absorber of  claim 22 , wherein the film includes polyethylene.