Correlation of Zwicker's Loudness and Other Noise Metrics with Drivers' Over-the-Road Transient Noise Discomfort

Results of a study are described in which driver subjective over-the-road noise discomfort ratings and objective measurements were collected and correlated for 10 driver subjects and an experimental matrix of test vehicles, transient road specimens, and repeated runs. Objective noise measurements included various time varying psychoacoustic Loudness and Sharpness metrics and Sound Pressure Level measurements. Results indicate that driver over-the-road noise discomfort is most strongly correlated with changes in the sound magnitude, for which Fast A-weighted SPL is almost as good a metric as Zwicker's Loudness, and to some extent is also correlated with the absolute sound level. Results also suggest that the change in the Aures' Sharpness of the sound and passenger car motion and vibration may also contribute to noise discomfort.