Perception of shape and material from contact sounds

Abstract

The perception of sources of percussive sounds, as a function of variables that govern sound synthesis, was investigated. In the first set of experiments, perception of the source’s material was investigated. Two types of experiments were conducted. In the first, subjects judged similarity with respect to material and length. The sounds corresponded to modal vibrations of struck clamped bars. They varied in fundamental frequency and frequency-dependent rate of decay. Differences between sounds in both decay and frequency affected similarity judgments, with decay playing a substantially larger role. In the second type of experiment, subjects assigned sounds to one of four material categories. Decay parameters for each category were estimated and found to correlate with measurements reported in the literature. The second set of experiments investigated perception of contact location on the object. Subjects were presented with pairs of sounds produced by striking a string at two locations. Two strings with different fundamental frequencies were used. In one experiment, subjects judged the distance between the strike points, and in another, judged which point was closer to the point of attachment. The results confirm that subjects are sensitive to the interstrike distance and can judge which point is closer.