Cross-Modal Frequency Matching: Sound and Whole-Body Vibration

Interest in human responses to whole-body vibration has grown, particularly due to the increasing usage of vehicles, e.g. cars, trucks, and helicopters etc. Another reason for growing interest in recent years is the importance of the vibrations generated by the performance of music for multimedia reproduction systems. There is a strong relationship between the frequency of the auditory stimulus and the frequency of the tactile stimulus, which simply results from the physical processes that generate the stimuli. The recordings in different vehicles or in different concert situations show that the whole-body vibration signal is like a low-pass filtered audio signal. The spectral contents, particularly low frequencies, are matched with each other. This correlation plays an important role in our integration mechanism of auditory and tactile information and in the perception of an immersive multimodal event. In this study, psychophysical experiments were conducted to investigate, if subjects are able to match the frequencies of two different sensory modalities with each other. In this experiment, sinusoidal sound and vibration signals were used. The auditory stimuli were presented to the subjects via headphones and the tactile stimuli were presented through a vibration seat. The task of the subject was to match the frequency of the whole-body vibration to the frequency of the auditory stimuli. The results show that the subjects are able to match the frequency of both modalities with some tolerances.