Sound absorption of a finite micro-perforated panel backed by a shunted loudspeaker.
Deep back cavities are usually required for micro-perforated panel (MPP) constructions to achieve good low frequency absorption. To overcome the problem, a close-box loudspeaker with a shunted circuit is proposed to substitute the back wall of the cavity of the MPP constructions to constitute a composite absorber. Based on the equivalent circuit model, the acoustic impedance of the shunted loudspeaker is formulated first, then a prediction model of the sound absorption of the MPP backed by shunted loudspeaker is developed by employing the mode solution of a finite size MPP coupled by an air cavity with an impendence back wall. The MPP absorbs mid to high frequency sound, and with properly adjusted electrical parameters of its shunted circuit, the shunted loudspeaker absorbs low frequency sound, so the composite absorber provides a compact solution to broadband sound control. Numerical simulations and experiments are carried out to validate the model.
Key Laboratory of Modern Acoustics and Institute of Acoustics, Nanjing University, Nanjing 210093, People's Republic of China.
Jiancheng
J
Tao
Key Laboratory of Modern Acoustics and Institute of Acoustics, Nanjing University, Nanjing 210093, People's Republic of China.
Ruixiang
R
Jing
Key Laboratory of Modern Acoustics and Institute of Acoustics, Nanjing University, Nanjing 210093, People's Republic of China.
Xiaojun
X
Qiu
D065966:Absorption, Physicochemical; D000162:Acoustics / Q000295:instrumentation*; D000669:Amplifiers, Electronic; D003198:Computer Simulation; D017097:Electric Impedance; D004867:Equipment Design; D008962:Models, Theoretical; D009038:Motion; D009716:Numerical Analysis, Computer-Assisted; D016062:Porosity; D015203:Reproducibility of Results; D013016:Sound; D013997:Time Factors; D014732:Vibration