Significance of height loudspeaker positioning for perceived immersive sound field reproduction

Abstract

Recently, new multichannel audio formats incorporating height loudspeakers have caught researchers' attention due to their ability to reproduce an immersive sound field. This study investigated the influence of the height loudspeaker positions and their signals on individually perceived sound quality. The authors generated nine-channel sound sources by convolving two anechoic musical pieces with nine selected room impulse responses measured in different distances and heights. In the listening test two layers of loudspeakers were used: the horizontal layer, following the standard ITU-R BS 775 five-channel loudspeaker configuration and the height layer (with elevation of 30°) with a total of twelve loudspeakers, located at ±30, ±50, ±70, ±90, ±110, and ±130 degrees. Four height signals were reproduced through eight different configurations of four height loudspeakers. Twelve listeners participated in the experiment, wherein they were asked to compare the randomly presented eight configurations and rank them based on their individually perceived sound quality. The experimental results indicate that despite the perceptual differences related to the room impulse responses, the perceived overall quality is significantly influenced by the positioning of the four height loudspeakers.