Ventilated low-frequency sound absorber based on Helmholtz acoustic metamaterial

In this work, we present a novel Helmholtz acoustic metamaterial (HAM) designed for ventilated low-frequency sound absorption. Based on COMSOL Multiphysics simulation results, a double-layer HAM achieves near-perfect sound absorption at approximately 687 Hz. Transmission loss within the range of 661 to 1074 Hz exceeds 10 dB. Both experimental measurements and theoretical calculations using the transfer matrix method validate the simulation results. A four-layer HAM enables effective broadband sound absorption across the range of 454 to 698 Hz. Consequently, our study presents a potential breakthrough in achieving effective low-frequency sound absorption across a broad spectrum in ventilated environments.