Robustness optimization of active headrest with virtual sensing to head rotation

Abstract

The movement and rotation of the human head will cause changes of acoustic transfer functions, leading to the performance deterioration of active headrests with virtual microphones. This paper uses a transfer response model optimization method to improve the performance robustness of active headrests with remote microphones to the head rotation. The variation of transfer functions with head rotation and the improvement of the system performance by the optimization method are analyzed for three different acoustic environments, including an anechoic chamber, a normal room and a lightly damped room. The experimental results verify that the optimization method can improve the performance robustness of the active headrest to head rotation under different acoustic conditions. When the head rotates from -90 deg. to 90 deg., the minimum noise reduction at 125Hz, 250Hz and 500Hz is improved by 7.2~11.0 dB. The noise reduction of the optimized system thus remains above 10 dB in the anechoic chamber and in the ordinary room, while in the lightly damped room the noise reduction is above 6 dB due to strong reflections.