Design of a built-in electroacoustic resonator for active noise reduction

The paper focuses on the design of a built-in electroacoustic device for active noise reduction purposes. The device basically encompasses a loudspeaker connected to a synthetic electrical impedance that enhances its ability to dissipate part of the incoming acoustic energy. The strategy is therefore to control some boundaries of enclosed sound spaces (such as room, cavity, etc.) rather than targeting a global control that requires significant input of additional acoustic energy. The main attraction of the proposed methodology is to achieve broadband sound absorption while bypassing the use of sensors. It is discussed how the relevant information on the sound field which is usually provided by sensors can be encapsulated into a synthetic electrical load. Computed and experimental results are provided to illustrate the benefits and potential of a built-in electroacoustic device compared to other options. Concluding remarks are made to discuss the foreseen future developments.