Study of Coupling Behavior of Acoustic Cavity Modes to Improve Booming Noise in Passenger Vehicles

Interior sound quality is one of the significant factors contributing to the comfort level of the occupants of a passenger car. One of the major reasons for the deterioration of interior sound quality is the booming noise. Booming noise is a low frequency (20Hz∼300Hz) structure borne noise which occurs mainly due to the powertrain excitations or road excitations. Several methods have been developed over time to identify and troubleshoot the causes of booming noise [1]. In this paper an attempt has been made to understand the booming noise by analyzing structural (panels) and acoustic (cavity) modes. Both the structural modes and the acoustic modes of the vehicle cabin were measured experimentally on a B-segment hatchback vehicle using a novel approach and the coupled modes were identified.

Panels contributing to booming noise were identified and countermeasures were taken to modify these panels to achieve decoupling of structural and cavity modes which results in the reduction of cabin noise levels. This is followed by countermeasure validation resulting into booming noise reduction.