Fig. 8: Meta-mufflers utilize Fabry-Pérot resonance in the acoustic design.
From: Resonance-based acoustic ventilated metamaterials for sound insulation
a The circular labyrinthine metamaterial and the transmission loss spectra. Reproduced with permission from ref. 130. b The muffler consisting of a series of crimped FP resonators and the absorption coefficient spectra. Reproduced with permission from ref. 132. c The labyrinth acoustic metamaterial and the coiled portion, as well as the absorption coefficient spectra. Reproduced with permission from ref. 129.
