Haptic-auditory distance cues in virtual environments: exploring adjustable parameters for enhancing experience

This paper investigates two subjective responses to a recorded percussive musical instrument sound displayed in a haptic-auditory virtual environment; the responses were apparent motion towards (AMT) and powerfulness. The system employed a whole-body actuator and full-range multichannel stereophonic sound compliant with ITU standards. AMT was experienced when whole-body vibratory components were slightly delayed in relation to sound components. Furthermore, the recorded percussive hit was initially observed to vary in its apparent power with variation in intermodal delay values and level; participants, therefore, made ratings of powerfulness. Threshold intermodal delays for experiencing AMT were found to depend strongly upon intermodal level values, but ratings of powerfulness were found to depend primarily upon whole-body vibration levels. These results can be incorporated into a structure for control response parameters in multimodal environmental display systems incorporating sound and whole-body vibration.