The Reduction of Vertical Interchannel Crosstalk: The Analysis of Localization Thresholds for Musical Sources

Musical sources were presented to subjects as phantom images from vertically arranged stereophonic loudspeakers. Loudspeakers were arranged in two layers: “main” and “height.” Subjects reduced the amplitude of the height layer until the resultant phantom image matched the position of the same source presented from the lower loudspeaker alone; this was referred to as the “localization threshold.” Delays ranging from 0–10 ms were applied to the height layer. The localization threshold was only significantly affected by the ICTD. The median threshold for 0 ms was –9.5 dB, which was significantly lower than the –7 dB found for the stimuli in which the height layer was delayed. No evidence was found to support the existence of the precedence effect in the median plane.