Sound localization precision under conditions of the precedence effect: effects of azimuth and standard stimuli.

Minimum audible angles (MAAs) were estimated for single noise bursts, and for burst pairs that satisfied the conditions of the precedence effect (that is, produced fused images). In one burst-pair condition, the bursts to be discriminated differed in lead location; in the other, they differed in lag location. Sounds were presented over loudspeakers. MAAs were lowest for single bursts, slightly higher for lead discrimination, and much higher for lag discrimination. Presence of a standard reference burst had no reliable effect on performance. The data are interpreted using a model of Shinn-Cunningham et al. [J. Acoust. Soc. Am. 93, 2923-2932 (1993)] in which discrimination of precedence-effect burst pairs is based on the lateral position of the auditory image, which is a weighted average of the positions of the leading and lagging bursts.