Broadband acoustic attenuation in microperforated meta-shells with ventilation

Abstract

Achieving sound attenuation across a broad frequency range while maintaining adequate ventilation remains a significant challenge in acoustic engineering, as there exists a rigid trade-off between attenuation ability and ventilation. In this Letter, we propose a double-layered microperforated meta-shells to serve as broadband acoustic ventilation barrier. Multiple scattering theory is first employed to characterize sound attenuation performance of the proposed design in terms of both sound absorption and transmission loss, which is not reported before. Experimental result demonstrates a good enhancement of absorption due to the insertion of inner shell with a specific perforation rate of micro cores. The mechanism can be attributed to the inter-cell coupling, which is further utilized to devise a different configuration by wrapping the meta-shell with porous sponge. It is found that adding an extra layer of sponge can further improve the low-frequency attenuation performance. The proposed broadband sound barrier with effective ventilation can find potential applications in architectural acoustics and office noise insulation.