| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to absorb sounds of only the bass by sticking an sound absorbing sheet consisting of a film-like material having a specific surface density to a rectangular frame and sticking a fibrous material of a specific density, as a backup material, to the rear surface of the sound absorbing sheet, thereby constituting the sound absorbing material. SOLUTION: The sound absorbing sheet 3 of a sound absorbing structure consisting of the film-like material having the surface density of 0.8 to 5.0 kg/m3 is stuck into the rectangular frame 2 and the fibrous material having the density of 24 to 80 kg/3 and a uniform thickness is stuck as the backup material 4 to the rear surface of the sound absorbing sheet 3. The frame 2 is constituted to have a dimension of 500×1000×50 nm. A surface material 5 having low air permeation resistance is installed to the front surface of the sound absorbing sheet 3. The sound absorbing material having the sound absorbing structure capable of absorbing the sounds of only the bass below 500 Hz may be obtained according to this constitution and the structure of the thinnest possible thickness may be obtained. The structure which does not change the sound absorbing characteristics even at points, such as corner parts, where standing waves are liable to arise may obtained.
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