Abstract: Aiming at reducing the interior noise, to quickly lock the key areas of vehicle body structure and put forward improvement, the premise is to get a clear understanding of core variables of car interior sound field. Therefore, in this paper, based on the calculation formula of interior sound field, relationship between variables and parameters and sound pressure response is analyzed. It is found that nodal line distribution is the core variable and increase of nodal line number can decrease the interior sound pressure. A prototype car is made and the conclusion is verified by the physical test. The conclusion is applied to the interior sound pressure control of a certain type of vehicle, which successfully reduces the interior sound pressure of the vehicle. It shows that the interior sound pressure can be controlled quickly based on the nodal line distribution.

Key words: structural acoustic field coupling system, frequency variable, mode variable, nodal line distribution