Time-Domain Acoustic Contrast Control with A Spatial Uniformity Constraint for Personal Audio Systems

Personal audio systems with multiple sound zones for listeners to enjoy different music/audio contents privately in a shared physical space have attracted great research interest in the past two decades. Acoustic Contrast Control (ACC) is one of the most popular methods for generating multiple personal sound zones because it produces the minimum inter-zone interference. However, the ACC method has been found to be inferior to the pressure matching method in terms of sound quality due to an uneven frequency response and nonuniform spatial sound field distribution in the bright zone. This paper proposes a spatial uniformity constraint on time-domain broadband ACC in addition to the frequency response trend estimation constraint with the aim of ensuring a uniform sound field distribution in the bright zone. Simulation results with measured room impulse responses demonstrate that the proposed algorithm reduces the magnitude variations in the bright zone to be less than 1 dB higher than the just noticeable level difference at a cost of a perceptually negligible degradation in acoustic contrast.