[Precedence effect at horizontal and vertical plane and moving lagging signal].

The precedence effect refers to the fact that humans are able to localize sound sources in reverberant environments. In this study, sound localization was studied with dual sound source: stationary (lead) and moving (lag) for two planes: horizontal and vertical. Duration of lead and lag signals was 1s. Lead-lag delays ranged from 1-40 ms. Testing was conducted in free field, with broadband noise busts (5-18 kHz). The listeners indicated the perceived location of the lag signal. Results suggest that at delays above to 25 ms in horizontal plane and 40 ms in vertical plane subjects localized correctly the moving signal. At short delays (up to 8-10 ms), regardless of the instructions, all subjects pointed to the trajectory near the lead. The echo threshold varied dramatically across listeners. Mean echo thresholds were 7.3 ms in horizontal plane and 10.1 ms in vertical plane. Statistically significant differences were not observed for two planes [F(1, 5) = 5.52; p = 0.07].