Spatial Effects on the Segregation of Sounds in Virtual Auditory Space

Human listeners can segregate sound sources based on differences in frequency content and timing. In addition, spatial separation has been shown to improve this ability. The work presented here is an attempt to characterise the effect of spatial factors on segregation when other distinguishing factors are either unavailable or unreliable. This is relevant to understanding how the auditory system deals with real environments, and is also relevant to the creation of virtual environments where particular auditory objects may need to be distinguishable from other objects. Experiments using various broadband sound sources (white noise, click trains, spoken words) indicate that the segregation of concurrent stimuli requires specific spatial arrangements that allow the auditory system to exploit binaural differences. Monaural spectral cues, while essential for spatialisation, seem to play little role in segregation under these conditions. However, they may be useful when competing stimuli have distinct temporal structures or do not fully coincide in time.