Electroacoustic metamaterials: Achieving negative acoustic properties with shunt loudspeakers

Electroacoustic absorbers: bridging the gap between shunt loudspeakers and active sound absorption.

The acoustic impedance at the diaphragm of an electroacoustic transducer can be varied using a range of basic electrical control strategies, amongst which are electrical shunt circuits. These passive shunt techniques are compared to active acoustic feedback techniques for controlling the acoustic impedance of an electroacoustic transducer. The formulation of feedback-based acoustic impedance co...

An Electroacoustic Analysis of Transmission Line Loudspeakers

Electroacoustic Absorbers I: Bridging a Gap between Active Sound Absorption and Shunt Loudspeakers

Variable acoustic properties can be obtained at the diaphragm of an electroacoustic transducer, with the help of very basic control strategies, among which is the simple electrical shunting of the transducer. These shunt techniques are compared to active feedback techniques for controlling the acoustic impedance of an electroacoustic transducer. It is shown here that the formulation of feedback...

Shunt Loudspeakers for Modal Control in Rooms

Engineers dealing with noise reduction in habitations close to transportation traffic or industrial facilities encounter several problems to decrease noise level in rooms at low frequencies. Passive materials and current building construction knowledge enable to avoid noise transmission in habitations at medium and high frequencies and the regulations based on the dBA scale can often be respect...

Electro-magnetically controlled acoustic metamaterials with adaptive properties.

A design of actively controlled metamaterial is proposed and discussed. The metamaterial consists of layers of electrically charged nano or micro particles exposed to external magnetic field. The particles are also attached to compliant layers in a way that the designed structure exhibits two resonances: mechanical spring-mass resonance and electro-magnetic cyclotron resonance. It is shown that...