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.
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http://dx.doi.org/10.1121/1.4836215 | DOI Listing |
Polymers (Basel)
July 2023
School of Mechanical & Automobile Engineering, Qingdao University of Technology, No. 777 Jialingjiang Road, Qingdao 266520, China.
To investigate the sound absorption of the absorber composed of a shunt loudspeaker (SL) and porous materials (PM) in tandem, the normal absorption coefficients for six samples of different groups of parameters are measured using impedance tubes. It is shown that a composite structure consisting of a porous material, an air layer, a shunt loudspeaker, and an air layer arranged in sequence (PM + Air1 + SL + Air2) has the potential to achieve broadband sound absorption close to three octaves in the frequency range of 200-1600 Hz. To further explore the sound absorption mechanism of "PM + Air1 + SL + Air2", a theoretical model based on the transfer matrix method is established, and a numerical model is built in the pressure acoustic module using COMSOL Multi-physics field software.
View Article and Find Full Text PDFSensors (Basel)
April 2021
Silesian University of Technology, Department of Measurements and Control Systems, Akademicka 16, 44-100 Gliwice, Poland.
Noise and vibration are common issues that may have a negative impact on human's' health. To minimize their consequences, several vibroacoustical methods may be employed. One well-known method is Piezoelectric Shunt Damping (PSD).
View Article and Find Full Text PDFSci Rep
July 2020
Centre for Audio, Acoustics and Vibration, Faculty of Engineering and IT, University of Technology Sydney, Sydney, Australia.
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.
View Article and Find Full Text PDFJ Acoust Soc Am
May 2014
Aerodynamics and Acoustics Laboratory, HKU Zhejiang Institute of Research and Innovation, Department of Mechanical Engineering, The University of Hong Kong, Hong Kong SAR, China.
Broadband noise with profound low-frequency profile is prevalent and difficult to be controlled mechanically. This study demonstrates effective broadband sound absorption by reducing the mechanical reactance of a loudspeaker using a shunt circuit through electro-mechanical coupling, which induces reactance with different signs from that of loudspeaker. An RLC shunt circuit is connected to the moving coil to provide an electrically induced mechanical impedance which counters the cavity stiffness at low frequencies and reduces the system inertia above the resonance frequency.
View Article and Find Full Text PDFJ Acoust Soc Am
January 2014
Key Laboratory of Modern Acoustics and Institute of Acoustics, Nanjing University, Nanjing 210093, People's Republic of China.
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.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!