Research on in-vehicle sound field zoning control integrating directional sound field and active noise control

Abstract

In response to the growing need for differentiated acoustic environments within automotive cabins and addressing the decline in in-vehicle sound field zoning performance due to interference from dynamic driving background noise, this study proposes a strategy that integrates directional sound fields with active noise control (ANC). Initially, a sound field zoning system employing a directional sound source was developed to analyze in-vehicle sound field zoning characteristics under various operating conditions. The findings revealed that, at idle, a sound pressure level (SPL) contrast of over 22.8 dB could be achieved between the driver’s position (bright zone) and the passenger’s position (dark zone), confirming the efficacy of the directional sound field in achieving sound field zoning. However, the performance of the zoning significantly decreased under varying vehicle speeds due to background noise in the bright zone. To address this issue, a control strategy integrating directional sound fields with ANC was proposed to actively reduce background noise in the bright zone, thereby enhancing the SPL contrast between the bright and dark zones. Furthermore, to resolve the interference of the audio signal on the feedback signal in the ANC for the bright zone background noise, the study proposed several variable step size control methods. Theoretical analysis demonstrated that the Quadratically Fading Momentum-Enhanced Variable Step Size Filtered-X Least Mean Square Method (QF-Mo-VSS-FxLMS) offered optimal performance. Finally, the effectiveness of the proposed strategy under different driving conditions was validated through simulation and hardware-in-the-loop testing, which showed that this strategy significantly enhanced the SPL contrast between the bright and dark zones and effectively improved zoning performance in complex acoustic environments. This research not only provides a theoretical basis and practical guidance for the application of vehicular directional sound fields but also paves a new technological path for personalized control within automotive acoustic environments.