Generation of multiple sound zones by spatial filtering in wavenumber domain using a linear array of loudspeakers

Novel signal processing is proposed for generating acoustically bright and dark zones at arbitrary horizontal positions using a linear array of loudspeakers. Most conventional methods are based on the numerical calculation of the inverse of the spatial correlation matrix between control points and the positions of the loudspeakers. However, such methods are quite unstable because the acoustic inverse problem is very ill-conditioned. On the other hand, in the proposed method, spatial filters in the wavenumber domain are analytically derived by introducing the spectral division method and modeling sound pressures at the control line as a rectangular window corresponding to bright and dark zones. Computer simulation results show that the proposed method can generate acoustically bright and dark zones more accurately than the conventional acoustic energy difference maximization method.