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

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 400–3200Formula: see textHz and above 0.7 between 250Formula: see textHz and 400Formula: see textHz. The total length of the proposed ABH is 155Formula: see textmm, in which the thickness of the MPPs is 0.5Formula: see textmm, the pore size is 0.3Formula: see textmm 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.