Largeness and shape of sound images captured by sketch-drawing experiments: Effects of bandwidth and center frequency of broadband noise

Abstract

When we listen to sounds radiated from a single sound source, the sound image is generally localized at a certain spatial position. In addition, similar to a visual image, the sound image has a certain largeness and shape. Previous works reported that a center frequency of the broadband noise affects the width of sound image; a bandwidth of broadband noise also affects the largeness of sound image. Although these works suggest that either the center frequency or frequency bandwidth has an impact individually on the largeness of sound image, an experiment employing simultaneous control of both parameters are required to explore how spectral characteristics of sound source signal affects the largeness of sound image. Furthermore, very little is known about the perception of the shape of sound image that would be essential for comprehensive understandings of spatial auditory perception. Therefore, in this work, a sketch-drawing experiment was conducted to capture the largeness and shape of sound image for a single sound source in an anechoic environment. The experimental results reveal that both the lower center frequency and the broader bandwidth of the broadband noise lead to the larger sound image. Moreover, the results show that inter- and intra-individual variations in the shape of sound image including circle, ellipse, and rectangular-like shape.