The effect of interchannel time difference on localization in vertical stereophony

Listening tests were conducted in order to analyze the localization of band-limited stimuli in vertical stereophony. The test stimuli were seven octave bands of pink noise, with center frequencies ranging from 125-8000 Hz, as well as broadband pink noise. Stimuli were presented from vertically arranged loudspeakers either monophonically or as vertical phantom images, created with the upper loudspeaker delayed with respect to the lower by 0, 0.5, 1, 5, and 10 ms (i.e., interchannel time difference). The experimental data obtained showed that localization under the aforementioned conditions is generally governed by the so-called "pitch-height" effect, with the high frequency stimuli generally being localized significantly higher than the low frequency stimuli for all conditions. The effect of interchannel time difference was found to be significant on localization judgments for both the 1000-4000 Hz octave bands and the broadband pink noise; it is suggested that this was related to the effects of comb filtering. Additionally, no evidence could be found to support the existence of the precedence effect in vertical stereophony.