Optimization of electric shunt resonant circuits for electroacoustic absorbers

Sound absorption can be achieved in a relatively simple manner with passive or active electroacoustic absorbers. Electroacoustic absorbers are basically loudspeakers, the membrane of which is used as an absorber/reflector of sound, and the electric terminals of which are connected to a dedicated electric load. This electric shunt can be a simple electric resistor, or an active device employing feedback control on acoustic and/or electric quantities (aka. direct impedance control). Whilst the latter allows significant broadening of acoustic absorption performances that could not be obtained with simple passive resistors, it is also possible to find passive shunt alternatives that allows interesting acoustic performances without the use of expensive and energy consuming electric disposals. A simple configuration of shunt electric resonator is proposed as an alternative to active shunt for broadening the performances of passive electroacoustic absorbers.