SOUND ABSORBING STRUCTURE

摘要

PROBLEM TO BE SOLVED: To effectively absorb noises in a low frequency band below 300 Hz in addition to noises in an intermediate and high frequency band by using the specific sound absorbing structure. SOLUTION: In a housing 41, a membrane vibration sound absorber 43 is arranged across a certain air layer 42 (Fig a). Or the housing 41 is filled with a soft fibrous porous sound absorber or continuous air foam type elastic foam sound absorber 46 (Fig b). Or the housing 41 is filled with the soft fibrous porous sound absorber or continuous air foam type elastic foam sound absorber 46 and the film vibration sound absorber 43 is arranged thereupon (Fig c). In this constitution, membrane vibration sound absorbing operation by the membrane vibration sound absorber 43 and sound absorption (γ) 47 by the friction and viscous resistance of the soft fibrous porous sound absorber or continuous air foam type elastic foam sound absorber 46 are performed. Further, a sound is absorbed by sound absorbing operation induced when the whole membrane vibration sound absorber 43 arranged on the filling layer of the soft fibrous porous sound absorber or continuous air foam type elastic foam sound absorber 46 vibrates through the spring operation of the filling layer.