Multizone soundfield reproduction using orthogonal basis expansion

We introduce a method for 2-D spatial multizone soundfield reproduction based on describing the desired multizone soundfield as an orthogonal expansion of basis functions over the desired reproduction region. This approach finds the solution to the Helmholtz equation that is closest to the desired soundfield in a weighted least squares sense. The basis orthogonal set is formed using QR factorization with as input a suitable set of solutions of the Helmholtz equation. The coefficients of the Helmholtz solution wavefields can then be calculated, reducing the multizone sound reproduction problem to the reconstruction of a set of basis wavefields over the desired region. The method facilitates its application with a more practical loudspeaker configuration. The approach is shown effective for both accurately reproducing sound in the selected bright zone and minimizing sound leakage into the predefined quiet zone.