Study on sound absorption performance of the broadband Helmholtz resonator array

In order to broaden the sound absorption band of Helmholtz resonators, a new Helmholtz resonator (HR) structure is proposed to achieve continuous broadband sound absorption in low frequency range. A tube-embedded HR with a single and double-layer neck overlap structure is proposed as the unit, and several units are connected in parallel to form an HR array, which can achieve a wide absorption band and can flexibly adjust its resonant frequency by changing the geometric parameters of each unit. Firstly, the sound absorption performance for the tube-embedded HR is analyzed. Then the sound absorption performances of the proposed parallel HR arrays with different parameters are discussed in detail. Finally, the experiments on the single and double-layer HR arrays are performed. The simulation and experimental results show that the proposed HR array can realize continuous broadband sound absorption in the target of 325-625 Hz with an average absorption coefficient greater than 0.8 and its thickness is only 1/30 of the working wavelength. This study provides an idea and method for the spatial structure design and multi-function design of broadband muffler.