Tuning of the acoustic impedance of a shunted electro-mechanical diaphragm for a broadband sound absorber

2019 ◽  
Vol 126 ◽  
pp. 536-552 ◽  
Author(s):  
Yumin Zhang ◽  
Chunqi Wang ◽  
Lixi Huang
Keyword(s):  
Acoustic Impedance ◽  
Sound Absorber ◽  
Broadband Sound

scholarly journals Subwavelength broadband sound absorber based on a composite metasurface

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Houyou Long ◽  
Chen Liu ◽  
Chen Shao ◽  
Ying Cheng ◽  
Kai Chen ◽  
...  
Keyword(s):  
Sound Absorber ◽  
Broadband Sound

Experimental study of smart sound absorber using multimode electromechanical coupling control in the low-frequency range

2021 ◽  
Vol 263 (3) ◽  
pp. 3800-3810
Author(s):  
Xiang Liu ◽  
Keming Wu ◽  
Lixi Huang
Keyword(s):  
Electromechanical Coupling ◽  
Electrical Response ◽  
Low Frequency ◽  
Design Procedure ◽  
Frequency Range ◽  
Acoustic Performance ◽  
Sound Absorber ◽  
Multiple Frequencies ◽  
Broadband Sound ◽  
Shunt Circuit

To construct a smart sound absorber in the low-frequency range with a wide control band, a piezoelectric ceramic (PZT) shunted with multiple resonance circuit is attached onto a micro-perforated panel (MPP) to perform as a smart sound absorber. The absorption can be controlled by the shunt circuit parameters conveniently. This smart micro-perforated panel (MPP) is investigated experimentally to explore the feasibility and design procedure in practical use. Based on the coupling among the acoustical, electrical, and mechanical fields, the proposed broadband sound absorber can achieve good acoustic performance on subwavelength scales. The electrical response of the shunt circuit is tested with a Network Analyzer. The acoustic performance of the smart sound absorber is measured in an impedance tube with the two-microphone transfer function method. The experimental results validate that the shunt circuit can resonate with the PZT patch at multiple frequencies, and hence improve the sound absorption of the smart absorber at these frequencies.

Optimization design and analysis of honeycomb micro-perforated plate broadband sound absorber

2022 ◽  
Vol 186 ◽  
pp. 108487
Author(s):  
Shanlin Yan ◽  
Jinwu Wu ◽  
Jie Chen ◽  
Yin Xiong ◽  
Qibo Mao ◽  
...  
Keyword(s):  
Optimization Design ◽  
Perforated Plate ◽  
Sound Absorber ◽  
Broadband Sound

scholarly journals Acoustic Properties of Sound Absorber from Modified Polyester with Filler Sodium Bicarbonate

2018 ◽  
Vol 34 (4) ◽  
pp. 2187-2191
Author(s):  
Nasmi Herlina Sari ◽  
Jauhar Fajrin
Keyword(s):  
Absorption Coefficient ◽  
Sodium Bicarbonate ◽  
Acoustic Impedance ◽  
Sound Absorption ◽  
Polyester Resin ◽  
Acoustic Properties ◽  
Acoustic Parameters ◽  
Absorbent Material ◽  
Sound Absorber ◽  
Absorption Performance

The combination of low price, ease of manufacturing and waterproofing characteristics has placed polyester resin as a potential sound absorbent material. Previous studies showed that adding filler material to the blending may increase the acoustics properties of a sound absorbent material. This study aims to investigate the potential of sodium bicarbonate (NaHCO3) to be employed as a filler to improve the acoustic properties of the sound absorber made of polyester resin. Two important acoustic parameters were carefully assessed; absorption coefficient and acoustic impedance. The results showed that the sound absorption performance increased significantly at low and medium frequencies in the presence of NaHCO3 filler in polyester resin. Meanwhile, the use of a back cavity on the absorbent material reduced the sound absorption performance of materials at low and medium frequencies. This suggests that sound absorber made of polyester with sodium bicarbonate filler may be used as an alternative for sound absorber materials.

Acoustic-Reflex Dynamics for Pulsed Signals

1978 ◽  
Vol 21 (2) ◽  
pp. 295-308
Author(s):  
Terry L. Wiley ◽  
Raymond S. Karlovich
Keyword(s):  
Duty Cycle ◽  
Acoustic Impedance ◽  
Normal Hearing ◽  
Broadband Noise ◽  
Threshold Shift ◽  
Temporary Threshold Shift ◽  
Acoustic Reflex ◽  
Stapedius Muscle ◽  
Duty Cycles

Contralateral acoustic-reflex measurements were taken for 10 normal-hearing subjects using a pulsed broadband noise as the reflex-activating signal. Acoustic impedance was measured at selected times during the on (response maximum) and off (response minimum) portions of the pulsed activator over a 2-min interval as a function of activator period and duty cycle. Major findings were that response maxima increased as a function of time for longer duty cycles and that response minima increased as a function of time for all duty cycles. It is hypothesized that these findings are attributable to the recovery characteristics of the stapedius muscle. An explanation of portions of the results from previous temporary threshold shift experiments on the basis of acoustic-reflex dynamics is proposed.

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