Extensity and depth perception of point and plane sound image

Using 31 speakers controlled by a PC, we investigated how the impression of a sound image changes when the area of sound sources changes. It was found that the distance of a sound image depends strongly on the area of sound sources. The distance of a sound image increases as the area of sound sources decreases. There were two contrasting tendencies with regard to change in the width of a sound image. One is that the width of a sound image changes in the same way as the area of sound sources changes, and the other is that the width of a sound image changes in the opposite way to change in the area of sound sources. Therefore, we conclude that this feeling is inadequate to express the difference in a sound image with r=1 (correlation coefficient factor r) when the area of sound sources changes.