2.5D multizone reproduction using weighted mode matching: Performance analysis and experimental validation

Mode-matching based multizone reproduction has been mainly focused on a purely two-dimensional (2D) theory, where infinite-long 2D secondary sources are assumed for 2D multizone reproduction. Its extension to the three-dimensional (3D) case requires more secondary sources and a higher computational complexity. This work investigates a more practical setup to use 3D sound sources as secondary sources for multizone reproduction in a 2D horizontal plane, i.e., 2.5D multizone reproduction. A weighted mode-matching approach is proposed to solve the dimensionality mismatch between the 2D desired sound field and 3D reproduced sound field. The weighting is based on an integral of Bessel-spherical harmonic modes over the entire control region. A detailed analysis of the weighting function is provided to show that the proposed method controls all the reproduction modes present on the 2D plane to minimize the reproduction error. The method is validated in both simulation-based and hardware-based experiments. The results demonstrate that in comparison with the conventional sectorial mode-matching method, the proposed approach can achieve more accurate reproduction over a wide frequency range and a large control region.