Active Noise Control over 3D Space: A Realistic Error Microphone Geometry Design

Spatial active noise control (ANC) aims to reduce unwanted acoustic noise over a continuous spatial region by generating an anti-noise field with secondary loudspeakers. Conventionally, spatial ANC is achieved by using complex error microphone arrays such as grid or spherical geometry, which are impractical and obstruct the users to enter the quiet region. Recently, a spatial ANC system using circular arrays of microphones has been proposed such that the lower hemisphere of the region of interest is free of microphones for user’s head movement. In this structure, however, the error microphone located at the center of the region (the origin) blocks the head from moving up. In this paper, we optimize the aforementioned system in terms of the error microphone geometry. We remove the requirement to have a microphone at the origin by introducing a single-channel remote microphone technique to the spatial ANC system. Through real-world experiments, we demonstrate that the proposed method achieves noise reduction over space with a more user-friendly error microphone array design.