Soundtrack loudness as a depth cue in stereoscopic 3D media

Abstract

Assisted by the technological advances of the past decades, stereoscopic 3D cues are being integrated increasingly in both interactive and non-interactive media. Arguably, the main focus of this effort is placed on the creation of an increased sense of visual depth. Considering that human perception relies heavily on the audiovisual integration rather than on visual information alone, it is rather surprising that relatively little attention has been given so far to the potential effect of the soundtrack on 3D depth perception in contrast to the evident interest towards the study of realistic 3D audio spatialisation techniques and technologies. The multisensory nature of human perception suggests that the potential of sound design as a means to influence depth perception in the stereoscopic 3D visual environments may be worthy of further exploration. This study reports on our research into the possibilities of using alterations of the volume levels of the soundtrack in order to influence the perception of visual depth while viewing stereoscopic 3D animation clips. Based on previous findings indicating that the volume level of the soundtrack may be related to the perception of visual depth, a series of experiments further explored the effectiveness of this auditory cue. Results suggest that, under certain conditions, differences in volume levels of the soundtrack could influence the judgement of visual depth in a way that frequently contradicts real-life expectations. It is suggested that different, more metaphorical perceptual mechanisms may be in play when viewing stereoscopic 3D presentations than in real life. In this context, we conclude that stereoscopic 3D media can benefit from further exploration of the effectiveness of certain auditory cues as a means to influence the perception of depth within the stereoscopic 3D environment.