Doppler Illusion Prevails Over Pratt Effect in Risset Tones.

Changes in frequency such as those found in Risset tones have been associated with moving sound sources in the vertical plane (Pratt effect) and the horizontal plane (Doppler illusion). We investigated the reported origin and motion of unspatialized Risset tones presented monotically and diotically, and Risset tones simulated to be in the sagittal or coronal plane, approaching or receding, from above or horizontally. Independent of the artificial spatialization used (none, spatializing frequency components collectively or individually, elevated or not), upward glissandi were more likely to be judged as approaching than receding, and downward glissandi as receding than approaching, in most cases from the horizon.