Panel Noise Contribution Analysis: An Experimental Method for Determining the Noise Contributions of Panels to an Interior Noise

A new method for estimating the sound pressure level (SPL) at a defined position of the interior is presented. It is possible to recalculate the interior noise dependent on the sound radiated by specified panels which encloses the interior. It could be applied to analyse the interior acoustics under different operating conditions. This could be normal driving on real roads or pure wind noise inside wind tunnels. Also it is possible to study the interior noise under an artificial force excitation applied to the trimmed body.

The method is based on the theoretical background of TPA (= Transfer Path Analysis /1/ ) via matrix inversion. It was tested on a simple cuboid structure with an artificial force excitation. The comparison of the measured and recalculated SPL of the interior shows a good correlation. Also the influence of some physical modifications at identified critical areas corresponds with the expected influence to the measured SPL inside this structure. After this first test, for a wind noise excitation a real car structure was investigated. Again the comparison of the measured and recalculated SPL inside the car shows a good correlation for a wide frequency range.

At last the method is discussed dependent on possible applications and alternatives which can be used for determining the noise contribution of the panels. Also a perspective in next steps of development and further applications is given.