Dual-band perfect low-frequency acoustic absorption based on metaporous composite

We present a low-frequency dual-band (303 and 356 Hz) perfect acoustic absorption (PA) metaporous. The metaporous composite is constructed by introducing Helmholtz resonance and Fabry-Perot resonance in porous materials. Our simulations show that the dual-band metaporous absorber has an ultra-thin thickness (lambda/18 for 356 Hz). Using the coupling of the three dual-band PA absorbers, the low-frequency high-efficiency (>90%) broadband acoustic absorption is obtained in the frequency range of 332-562 Hz. Experiments confirm the dual-band perfect acoustic absorption and high-efficiency broadband acoustic absorption. The metaporous composite could have promising potential for low-frequency noise reduction.