Perception of rubbing sounds

When people interact manually with solid objects, the interactions are generally coupled with rubbing, scraping, or other impact sounds. In virtual reality, such sounds are mostly lacking, thus affecting the naturalness of the interactions with the virtual objects. This contribution deals with the perceived properties of rubbing sounds, generated by, e.g., gliding a sheet of paper on a table surface. This sound appears to consist of high-pass filtered noise. An experiment is described in which synthetic rubbing sounds were varied in respect of their high-pass cut-off frequency and their spectral balance. Subjects were asked to estimate the distance traveled during the rubbing movement, and to indicate the effort with which the paper was pressed on the table during the gliding movement. The results show that the perceived distance traveled is positively related with spectral balance, while the cut-off frequency did not affect perceived distance. The perceived pressure exerted is negatively related with both cut-off frequency and spectral balance. The results are applied on a tablet to synthesize natural sounding rubbing sounds when moving over the surface of the tablet.