Interior Noise Analysis Based on Acoustic Excitation Tests at Low-Frequency Range

An experimental analysis is performed on structure-borne sound in the low-frequency range under 50 Hz by applying an acoustic excitation test to a fully trimmed vehicle. This analysis makes use of the structural-acoustic reciprocity technique in which the vibration distribution of the car body is measured while the vehicle is being acoustically excited by a loudspeaker placed at the position of a passenger's ear. This paper explains why the concept of reciprocity should be applied to the study of low-frequency structure-borne sound, and discusses the causes of road noise, a typical problem in structure-borne sound associated with passenger cars.