Sound Quality Aspects of Impact Harshness for Light Trucks and SUVs

Impact harshness characterizes interior sound and vibration resulting from tire interactions with discrete road disturbances. Typical interactions are expansion joints, railroad crossings, and other road discontinuities at low-to-medium vehicle speeds. One goal of the current study was to validate for light trucks and SUVs the metric that was developed for cars: a weighted combination of peak loudness values from the front and rear impacts after lowpass filtering at 1 kHz. Another goal was to see if other sound characteristics of impact harshness needed to be captured with a metric.

A listening study was conducted with participants evaluating several different trucks and SUVs for impact harshness. Results show that the existing metric correlates well with subjective preferences for most of the vehicles. Further analysis shows that characterization of a “Loose/Tight” dimension needs to be included with the existing metric in order to correlate well with subjective preferences for all of the vehicles. The results of this study suggest that the Loose/Tight dimension needs to be objectively quantified.