Panning between non-symmetric loudspeaker pairs distorts perceived spatial width.

Evidence

When a virtual source is panned between loudspeakers, the binaural cues are more or less unnatural, since the summing localization mechanism produces somewhat unnatural cues even in the stereophonic case. With loudspeaker pairs not symmetric about the median plane, the produced ITD and ILD cues suggest different directions at different frequencies and are also biased somewhat towards the median plane (Pulkki, 2001b). As a result, the perceived spatial width of the virtual source varies with the panning direction. Thus, the directions of the loudspeakers are perceived if a moving source is created, since the virtual sources are more point-like in their directions. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1895