Vehicle Interior Multi-Zone Sound Field Reproduction with Uncertain Disturbance of Acoustic Transfer Function

Multi-zone sound field reproduction uses the loudspeaker array to divide the space into different zones, which is a sound field control method to meet the different requirements of listeners in each zone. Since the vehicle interior is a small and enclosed space, the disturbance of acoustic transfer function (ATF) caused by scattering and reverberation in the acoustic environment and external noise will greatly affect the control effect. Certain predictable and measurable disturbances of ATF can be solved through error modeling or active control. However, due to the presence of disturbances that cannot be measured in advance, the effect of multi-zone sound field reproduction is barely satisfactory. In this paper, the maximum normalized recovery control (MNRC) is proposed to improve the robustness of multi-zone sound field reproduction. By measuring ATF in the actual car and calculating the expected ATF, the magnitude variation range of ATF is confirmed. Then, through normalizing the maximum value of the ATF matrix before being disturbed, the transmission characteristics are preserved, allowing for good multi-zone sound field reproduction performance even in the presence of unpredictable disturbances. The MNRC method does not require any error parameters of uncertain disturbance except for its amplitude variation range, reducing the preliminary preparation work for multi-zone sound field reproduction. Through simulation and experimental verification, the results show that when controlling the disturbed sound field, the MNRC method has a significant improvement compared to classic multi-zone sound field reproduction method. Furthermore, the performance in certain frequency bands is even better than the effect before being disturbed.