Sound zone control with fixed acoustic contrast and simultaneous tracking of acoustic transfer functions

As environmental changes are inevitable, online algorithms that can track the variation of acoustic transfer functions are preferred in sound zone control (SZC) systems. In this paper, it is found that for the time domain SZC, the nonuniqueness problem caused by the coupling in multichannel transfer function modeling can be solved with time-varying control filters. To keep a stable acoustic contrast (AC) performance irrespective of environmental changes and also avoid the extreme distortion introduced by maximizing the AC in the time domain, the objective of maintaining a desired level of AC is used and an adaptive control algorithm is developed. The simulations validate that the proposed method tracks the environmental changes and adapts the control filters to give a stable AC performance.