Sound transmission loss by a hexagonal acoustic metapanel under random incidence

Investigating sound attenuation in subwavelength regimes remains challenging with conventional materials. Previous studies have examined locally resonant acoustic metamaterials (AMMs) with a negative bulk modulus, achieved through multiple in-parallel Helmholtz resonators, which generate bandgaps that enhance acoustic transmission loss. Here, we extend the analysis of a hexagonal AMM by predicting sound transmission loss (STL) under random incidence, further broadening its applicability in practical acoustic engineering.