Dual frequency sound absorption with an array of shunt loudspeakers

Pengju Zhang; Chaonan Cong; Jiancheng Tao; Xiaojun Qiu

doi:10.1038/s41598-020-67810-z

Dual frequency sound absorption with an array of shunt loudspeakers

Sci Rep. 2020 Jul 2;10(1):10806. doi: 10.1038/s41598-020-67810-z.

Authors

Pengju Zhang^#¹, Chaonan Cong^#², Jiancheng Tao³, Xiaojun Qiu⁴

Affiliations

¹ Key Laboratory of Modern Acoustics and Institute of Acoustics, Nanjing University, Nanjing, China.
² Department of Physics, China Jiliang University, Hangzhou, China.
³ Key Laboratory of Modern Acoustics and Institute of Acoustics, Nanjing University, Nanjing, China. jctao@nju.edu.cn.
⁴ Centre for Audio, Acoustics and Vibration, Faculty of Engineering and IT, University of Technology Sydney, Sydney, Australia.

^# Contributed equally.

Abstract

Transformer noise is dominated by low frequency components, which are hard to be controlled with traditional noise control approaches. The shunt loudspeaker consisting of a closed-box loudspeaker and a shunt circuit has been proposed as an effective sound absorber by storing and dissipating the electrical energy converted from the incident sound. In this paper, an array of shunt loudspeakers is proposed to control the 100 Hz and 200 Hz components of transformer noise. The prototype under tests has a thickness of 11.8 cm, which is only 1/28 of the wavelength of 100 Hz. The sound absorption performance of the array under random incidence is analyzed with the parallel impedance method, and the arrangement of array elements is optimized. The test results in a reverberation room show that the proposed array has sound absorption coefficients of 1.04 and 0.93 at 100 Hz and 200 Hz, respectively, which provides potential of applying this type of thin absorbers for low-frequency sound control.