Multiple echoes precedence effect

Gongqiang Yu, Ruth Y. Litovsky
2007 Journal of the Acoustical Society of America  
The precedence effect has been explored extensively using a lead and a single lag (simulated echo). For click stimuli, when the lead-lag delay is a few ms, discrimination of directional changes in the lag are poorer than for the lead. This study was aimed at determining whether the effects would be upheld in a three-source paradigm and to explore the extent to which the three sources interact. Three binaural click pairs (Lead, Lag1, and Lag2) were presented over headphones. Discrimination of
more » ... ectional changes in each click pair was measured using an ABX, 2AFC task, for delays of 0--130 ms. Results replicated classic findings with a single lag, but also showed that (1) for delays above 16 ms a temporal order effect resulted in poorer lead discrimination and better Lag2 discrimination; (2) echo thresholds were complicated by the addition of Lag2; and (3) an interaction was observed between Lag1 and Lag2 at very brief time delays such that summing localization resulted in improved discrimination of lagging sound sources. These results suggest that in a multi-echo situation the directional cues from echoes that occur after the classic lead-lag pair can contribute in the localization process and introduce complexities.
doi:10.1121/1.4781975 fatcat:obqjo2refbcp3j4x3t7rek4y2e