Sound absorption method based on impedance matching
For low and intermediate frequency incident sound waves,the active sound absorption method can obtain better absorption performance,but for high frequency incident sound waves,it can not achieve good absorption performance.In order to solve this problem,a semi-active sound absorp-tion method is proposed to change the acoustical absorption coefficient by adjusting the surface imped-ance of the loudspeaker behind the sound absorption material.First,the controllable loudspeaker is placed behind the sound absorbing material,and its surface impedance is adjusted to make it match the acoustic impedance of air optimally,so as to realize the effective regulation of the sound absorbing per-formance.The experimental results show that the method can adjust the acoustical absorption coeffi-cient effectively while continuously changing the frequency of incident sound wave,ensuring that a-coustical absorption coefficient remains at its maximum value.
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