Study on broadband low-frequency sound insulation of multi-channel resonator acoustic metamaterials

A novel acoustic metamaterial structure, made up of both resonator and multiple channels, is proposed to insulate low-frequency broadband noises. Three bandgaps with a total width of 658 Hz can be obtained below 900 Hz when the structure appears as a single negative characteristic within specific frequency ranges. These bandgaps are caused by the standing-wave characteristics under the coupling action of the interior and exterior cavities and the multiple channels. By changing structural parameters and materials, the low-frequency broadband sound insulation performance of the structure can be improved. Experimental results further prove the sound insulation characteristics. The results obtained herein can be used as a guide toward achieving low-frequency broadband sound insulation using a lightweight structure.