Active Control of Wall Acoustic Impedance

Abstract We attempt here the active control of enclosed sound fields via wall impedance changes. The impedance value which is the most efficient in silencing a cavity is the central point of this paper. Simulations and experiments show that the optimal impedance is not necessarily characterized by an large amount of absorbed power. Its silencing effect depends also on its ability to reduce source radiation. Experiments including fluid-structure interaction are also presented.

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Planar acoustic metamaterials with the active control of acoustic impedance using a piezoelectric composite actuator

2013 Joint IEEE International Symposium on Applications of Ferroelectric and Workshop on Piezoresponse Force Microscopy (ISAF/PFM) ◽

10.1109/isaf.2013.6748720 ◽

2013 ◽

Cited By ~ 1

Author(s):

Katerina Novakova ◽

Pavel Psota ◽

Roman Dolecek ◽

Vit Ledl ◽

Pavel Mokry ◽

...

Keyword(s):

Active Control ◽

Acoustic Impedance ◽

Piezoelectric Composite ◽

Acoustic Metamaterials ◽

Composite Actuator

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Active control of wall acoustic impedance

AIAA Journal ◽

10.2514/3.14250 ◽

1999 ◽

Vol 37 ◽

pp. 825-831 ◽

Cited By ~ 1

Author(s):

Hongwu Zhao ◽

Xiaofeng Sun

Keyword(s):

Active Control ◽

Acoustic Impedance

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Active control of acoustic impedance with a multi‐element system

The Journal of the Acoustical Society of America ◽

10.1121/1.412801 ◽

1995 ◽

Vol 97 (5) ◽

pp. 3339-3339

Author(s):

Brian H. Houston ◽

Douglas M. Photiadis ◽

J. A. Bucaro ◽

Robert D. Corsaro ◽

Larry A. Kraus

Keyword(s):

Active Control ◽

Acoustic Impedance ◽

Element System

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Acoustic-Reflex Dynamics for Pulsed Signals

Journal of Speech and Hearing Research ◽

10.1044/jshr.2102.295 ◽

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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