Multizone sound reproduction in reverberant environments using an iterative least-squares filter design method with a spatiotemporal weighting function

A previously proposed iterative filter design procedure, referred to as Iterative DFT-domain Inversion (IDI), is applied in the context of multizone sound reproduction in reverberant environments. The IDI approach aims at iteratively solving a least-squares problem, where the true reproduction error in the time domain is considered rather than narrowband errors in the frequency domain. In this paper, a spatiotemporal weighting function, which can be tailored to the problem at hand, is applied to the reproduction error in order to flexibly control the behavior of the designed rendering system, where a constraint is imposed on the energy of the impulse responses of the loudspeaker prefilters. The efficacy of the proposed spatiotemporal weighting is verified experimentally. In particular, it is shown that the acoustic contrast between the local listening areas can be significantly increased by allowing for a certain amount of reverberation in the bright zone. At the same time, the accuracy of the first wave front synthesized in the bright zone remains unaffected. Furthermore, undesired pre-echoes-which occur prior to the desired wave front and may impair the perceived location of the synthesized source, but also the crispness of impulsive sounds-can be reduced.