Psychoacoustic estimation of differential mass threshold

Authors:

• Mutsumi Ishibashi,
• Anna Preis

Abstract

Psychoacoustic experiments are designed to assess the attributes of sound sensation. However, in ordinary life audition does not help us to detect the properties of an acoustic signal, but rather the properties of a signal's source. We decided to design an experiment in which subjects were exposed to the sounds of falling balls and were expected to estimate their mass. The question was: is there a regularity in subjects' responses that allows them to denote the differential mass threshold of the sound source? In our study the seven iron balls of different weights were dropped from two different heights onto two types of floor material. The sound of the falling balls was recorded with the help of a dummy head in a semi-soundproof room. From the sounds recorded, single floor impact sounds of 300ms duration were identified and analysed. In the hearing test, 7 subjects judged which of the two sounds presented in a pair was generated by a heavier ball. As a result, the differential mass thresholds were obtained. A high correlation was found between the differential mass thresholds and the differences in the loudness and sharpness of the sounds generated by the balls of different weight.