Acoustic Switch based on Rotatable Sonic Crystal with Multiresonant Scatterers

This research introduces an acoustic switch based on a Sonic Crystal (SC) containing multiresonant scatterers. The SC operates in a square 2D lattice configuration with scatterers containing Helmholtz resonators (HRs) tuned to di!erent frequencies. By rotating all scatterers by 90°, the interaction between the Bragg bandgaps (Bragg BGs) and the HRs’ BGs can be mod- ified, allowing selective frequency filtering and control of wave propagation. Although SCs operating at low frequencies have been widely investigated, the implementation of reconfigurable acoustic switches in the low-to-mid fre- quency range (500–2500 Hz) remains scarce. This is one of the novelties highlighted in the present study. The simplicity and cost-e!ectiveness of the 3D-printed structure, coupled with its hollow design that minimizes ab- sorption, enhances its practicality. Experimental validation conducted in an anechoic chamber shows a significant change in acoustic insulation per- formance, with a maximum contrast ratio of 20 dB. This design opens up new possibilities for noise reduction in urban and industrial environments, adaptive acoustic environments, acoustic sensors, and even acoustic energy harvesting.