Helmholtz resonator is a very common anechoic measure, and it is widely used in pipe acoustic fields. Based on the enlightenment of the classic Helmholtz resonator, this paper proposes a headrest resonator model and extends it to the acoustic field of the passenger cabin to improve the road noise in the car.
Firstly, through the theoretical model of Helmholtz resonator, the relationship between its resonance frequency and the geometric size of the resonator is clarified. Secondly, the influence of the headrest resonator on the acoustic field characteristics of the car is studied through finite element simulation analysis. It is demonstrated that the headrest resonator is placed in the car, and the sound pressure distribution characteristics of the passenger's inner ear near the resonance frequency change significantly. At the same time, through 3D printing, a sample of the headrest resonator is made. In addition, the acoustic test of the passenger cabin-headrest resonator coupling system is designed, and the test results are compared with the simulation results, which proves the effectiveness of the headrest resonator in improving the acoustic field characteristics in the car. And the test further verifies that the headrest resonator reduces the peak of the vehicle road noise of 120Hz by 3-5dB.
It is hoped that the research in this paper can provide a low-cost-effective solution and enlightenment for the improvement of low-frequency noise in the car.