From various methods of measuring noise of a motor vehicle, there is a
lack application on how to obtain the ‘pure’ airborne noise in a vehicle cabin as an
important measure to improve the noise control treatment. This project proposes a
technique in separating airborne and structure-borne noise in a motor vehicle
using sound source substitution method. A cone loudspeaker was used as the
substitution source and the overall transmission loss was measured to achieve this
purpose. It is found that the structure-borne noise is dominant at low frequencies
and airborne noise dominates at high frequency. The intersection frequency
between the two is roughly 400 Hz