Relationship between frequency shifting of vehicle sounds and acceleration impression

A paired comparison test using audio and visual stimuli was conducted to examine the relationship between frequency shifting and the acceleration impression of vehicles. The results showed that frequency shifting can enhance the vehicles' acceleration impression for both pedestrians and passengers in the vehicles. It was also shown that the acceleration impression is affected by not only the rate of shifting but also its band. The majority of the stimulus conditions that contained a 2,000-Hz-band component had a positive effect on the acceleration impression. The band and rate of frequency shifting also had an effect on the harmonization between the impression of audio and the visual acceleration. In the future, our aim is to investigate a comprehensive impression and to explore the capabilities of a designed application. Moreover, the actions of a driver may potentially have an effect on the acceleration impression, and hence, an examination using a driving simulator is also a part of our future work.