Evaluating Acoustic Warning Signals in Automobile Interiors

The use of acoustic warning signals to provide information about vehicle conditions to the driver and passengers is now possible through application of advanced electronics in recent automobile designs. These acoustic warning signals may be tones or synthesized voice. The signals can only be effective if they are audible and distinguishable by the vehicle occupants without being at an irritating level. This paper presents a method for measuring acoustic intensity in an automobile interior using the cross-spectral technique which may assist in determining audibility of signals. Effective methods for displaying these quantitative vector measurements using computer graphics are presented along with the results of testing. Finally, an important future need of correlating acoustic intensity measurements with published human perception levels is discussed.