A Review of Microperforated Panel-Based Structures for Low Frequency Sound Absorption

The use of sound absorption materials has traditionally been restricted to medium-to-high frequencies due to their limitations at low frequencies, where the large wavelength of sound waves imposes rather bulky solutions. However, recent materials and designs allow for the absorption of sound waves with more practical sizes and weights, reviving interest in this frequency range. Some of these low-frequency absorbers, also named acoustic metamaterials or sub-wavelength sound absorbers, based on microperforated panels, are reviewed in this article. These include multilayer and multicavity microperforated panels, hybrid passive–active absorbers, multiple Helmholtz resonators, and microperforated panels with labyrinthine cavities or sonic black holes.