The main content of NVH research is the influence of interior noise and vibration on vehicle performance and comfort. Engine, exhaust system, wind noise when driving at high speed, tire noise and friction between other components are the main sources of noise. The engine, transmission system and uneven road surface are all the sources of vehicle vibration. The noise in the car is usually generated from the outside and transmitted to the car. 

Air transfer and solid transfer are the two main ways of noise transmission. Some data show that when the noise is transmitted to the vehicle, the medium and low frequency noise (30-400hz) is usually transmitted through the structural vibration, while the high frequency noise is transmitted from the air to the vehicle interior through the holes and gaps in the vehicle body. If the solid propagation can be reduced, the noise will be reduced to a large extent.