Effects of reverberation on fusion of lead and lag noise burst stimuli

The purpose of this investigation was to determine the effects of reverberation on the precedence effect by obtaining thresholds for perception of leading and lagging noise burst stimuli as separate auditory events. In Experiment 1, lag burst thresholds for 4-ms noise bursts were measured in a simulated reverberant and anechoic environment for nine subjects with normal hearing at presentation levels of 10, 20, and 30 dB SL. Results indicated that lag burst thresholds obtained in the reverberant environment were higher than those obtained in the anechoic environment, with no effect of sensation level. In Experiment 2, three new stimulus conditions, two monaural and one binaural control, were employed. For one monaural condition, the stimuli were equal in level and for the other, the leading stimulus was more intense than the lagging stimulus. For the binaural control condition, the stimuli were presented from a perceived spatial location of 0° azimuth. In the monaural and binaural control conditions, lag burst thresholds were lower than those obtained in the reverberant environment of Experiment 1. There was no difference between lag burst thresholds obtained in either environment for the monaural and binaural control conditions compared to the anechoic condition of Experiment 1. Results of Experiment 2 indicate that the higher lag burst thresholds observed in Experiment 1 are not fully explained by a peripheral masking effect.