Limits of Noise Control over Space
* Presenting author
This paper investigates the best possible performance of noise cancellation over a region of space for a fixed set of secondary sources within a given acoustic environment. We first formulate the spatial active noise control (ANC) problem in a 3-D acoustic enclosure (room). Secondly, we derive a wave-domain least square method by matching the secondary sound field to the primary sound field in wave domain. Thirdly, we propose a subspace method by matching the secondary field coefficients to the projection of primary sound field in the subspace. Simulation results compare between the wave-domain least square method and the subspace method, in terms of energy of the loudspeaker driving signals, noise reduction inside the region, and residual noise field outside the region. The subspace matching method provides the limits of the ANC system for the given constraints and the acoustic characteristics of the room.