Effects of stimulus order on auditory distance discrimination of virtual nearby sound sources

Stimulus order has been reported to affect perceived loudness. This letter investigates how temporal order affects distance discrimination of receding and approaching pairs of sound sources rendered binaurally in the anechoic near-field. Individual discrimination thresholds for different virtual locations were measured through an adaptive procedure. The threshold values show a bias toward approaching stimuli for closer reference distances (<= 50 cm) and toward receding stimuli for farther reference distances (100 cm), but only when absolute intensity cues are available. The results show how an illusion of loudness can translate into an illusion of perceived relative distance.