Measurement of Truck and Vehicle Noise

This paper reviews general methods of identifying noise sources in machinery and in particular it describes in detail two methods which have been studied by the authors on a truck: near field measurements and the coherence technique. The results of these two methods are compared with results of a third method in which the same truck with different sources wrapped and then sequentially exposed was driven past a microphone using the SAE J366b test.

The paper also reviews two different stationary indoor standard tests which have been investigated: the reduced drive-by simulation method, and the sound power method. These tests could be used to supplement (or replace) the standard SAE J366b drive-by test in some cases. Comparisons are made of data from the two tests developed and the SAE J366b drive-by data for the same truck.