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SUMMARY:Electroacoustic Absorbers : from the electric shunting of a loudsp
 eaker to active acoustic impedance control
DTSTART:20101203T101500
DTSTAMP:20260916T055731Z
UID:4a9a497b0d34cdc74a94125b8aeb1d21d223e959a82308ccfdafbcd6
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr. Hervé Lissek\, Laboratoire d’Electromagnétisme et d’
 Acoustique\, EPFL\nVariable acoustic properties can be obtained at the dia
 phragm of an electroacoustic transducer\, with the help of very basic cont
 rol \nstrategies\, among which is the simple electrical shunting of the \n
 transducer (shortcut or variable shunt impedance). These passive shunt \nt
 echniques are compared to active acoustic feedback techniques aiming \nat 
 controlling the acoustic impedance of an electroacoustic transducer. \nIt 
 is shown here that the formulation of feedback-based acoustic \nimpedance 
 control reveals singular analogies with shunt strategies\, and \nhighlight
 s an original strategy for synthesizing electric networks \n("shunts") wit
 h positive or negative components\, bridging a gap between \npassive and a
 ctive acoustic impedance control. We present the theory \nunifying all the
 se passive and active acoustic impedance control \nstrategies\, introducin
 g the concept of electroacoustic absorbers. The \nequivalence between (pas
 sive) shunt and active feedback control is \nformalized\, on the one hand 
 through the introduction of a 1-degree-\nof-freedom active acoustic resona
 tor accounting for both electric \nshunts and acoustic feedbacks\, and on 
 the other hand through the \nintroduction of equivalent electric networks 
 that mimic the \nperformances of feedback-based active techniques. Simulat
 ions and \nexperimental results are presented\, with an emphasis on formal
  \nanalogies between the different acoustic impedance control techniques.
LOCATION:ME C2 405
STATUS:CONFIRMED
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