Patent ID: 6021612
Filing Date: 2000-02-08
Classification: E01F,E04B,G10K

Abstract:
A sound absorbing wall panel comprising:an external Helmholtz acoustical resonator includinga front skin of the panel adapted to face a source of noise;a back skin of the panel held in spaced relation to the front skin;perimeter structure between the skins andorifices in the front skin to permit sound waves to enter into a cavity between the skins and perimeter structure;a plurality of internal Helmholtz acoustical resonators enclosed within the cavity and having respective differing natural frequencies within a predetermined bandwidth of said noise;said external acoustical resonator having a natural frequency within said bandwidth and higher than said respective natural frequencies;said higher frequency determined by said orifices and the volume of said cavity less volumes of the internal acoustical resonators;said internal acoustical resonators adapted to be slidably inserted into and randomly positioned within said cavity;so that said acoustical resonators of the panel dissipate significant levels of sound energy at and about said higher and respective lower natural frequencies.