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SUMMARY:Electroacoustic Absorbers : from the electric shunting of a loudsp
 eaker to active acoustic impedance control
DTSTART:20101203T101500
DTSTAMP:20260921T013858Z
UID:2b48e27fd513a7221eae52024b54c003a37fd9c055c8e73449de1413
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 \nelectroacoustic transducer\, with the help of very basic co
 ntrol \nstrategies\, among which is the simple electrical shunting of the 
 \ntransducer (shortcut or variable shunt impedance). These passive shunt \
 ntechniques are compared to active acoustic feedback techniques aiming \na
 t controlling the acoustic impedance of an electroacoustic transducer. \nI
 t is shown here that the formulation of feedback-based acoustic \nimpedanc
 e control reveals singular analogies with shunt strategies\, and \nhighlig
 hts an original strategy for synthesizing electric networks \n("shunts") w
 ith positive or negative components\, bridging a gap \nbetween passive and
  active acoustic impedance control. We present the \ntheory unifying all t
 hese passive and active acoustic impedance control \nstrategies\, introduc
 ing the concept of electroacoustic absorbers. The \nequivalence between (p
 assive) shunt and active feedback control is \nformalized\, on the one han
 d through the introduction of a 1-degree-\nof-freedom active acoustic reso
 nator accounting for both electric \nshunts and acoustic feedbacks\, and o
 n the other hand through the \nintroduction of equivalent electric network
 s that mimic the \nperformances of feedback-based active techniques. Simul
 ations and \nexperimental results are presented\, with an emphasis on form
 al \nanalogies between the different acoustic impedance control techniques
 .
LOCATION:ME C2 405
STATUS:CONFIRMED
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