Broadband sound absorption using acoustic black holes with micro-perforated panels

Abstract

In order to achieve broadband sound absorption, we propose a composite structure combining acoustic black holes (ABHs) and micro-perforated panels (MPPs). Here, we adopt both simulant and experimental methods to describe the sound transmission mechanism of the proposed composite ABH. This mechanism allows the ABH to have a sound absorption coefficient of over 0.8 in the range of 400–3200[Formula: see text]Hz and above 0.7 between 250[Formula: see text]Hz and 400[Formula: see text]Hz. The total length of the proposed ABH is 155[Formula: see text]mm, in which the thickness of the MPPs is 0.5[Formula: see text]mm, the pore size is 0.3[Formula: see text]mm and the porosity is 0.1 and 0.16, overcoming the length size and bandwidth limit for sound wave suppression in current ABHs. This work can further progress in elucidating the acoustic characteristics of ABH and open new avenues in ultra-broad-band sound wave control.