Constructing and disrupting listeners’ models of auditory space

Department of Communications Disorders, University of Massachusetts, 6 Arnold House, Amherst, Massachusetts 01003, USA.
The Journal of the Acoustical Society of America (Impact Factor: 1.5). 01/2007; 120(6):3957-65. DOI: 10.1121/1.2354020
Source: PubMed


A major problem for an auditory system exposed to sound in a reverberant environment is to distinguish reflections from true sound sources. Previous research indicates that the process of recognizing reflections is malleable from moment to moment. Three experiments report how ongoing input can prevent or disrupt the fusion of the delayed sound with the direct sound, a necessary component of the precedence effect. The buildup of fusion can be disrupted by presenting stimuli in alternation that simulate different reflecting surfaces. If buildup of fusion is accomplished first and then followed by an aberrant configuration, breakdown of the precedence effect occurs but it depends on the duration of the new sound configuration. The Djelani and Blauert (2001) finding that a brief disruption has no effect on fusion was confirmed; however, it was found that a more lengthy disruption produces breakdown.

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    • "Similarly, listening to a series of sounds with identical locations and onset asynchronies produces a buildup of the precedence effect such that listeners report that echoes fade out across the presentation of several pairs regardless of presentation rate (Clifton & Freyman, 1989; Freyman, Clifton, & Litovsky, 1991). The results of these experiments along with other studies exploring the precise conditions that result in both the breakdown and buildup of the precedence effect are consistent with the hypothesis that listeners build complex models of the acoustically reflective surfaces in a room based on experience with sounds in that setting (Blauert, 1997; Clifton, Freyman, Litovsky, & McCall, 1994; Clifton, Freyman, & Meo, 2002; Freyman & Keen, 2006). Additionally, asymmetries arise in the buildup of the precedence effect that are not evident when onset asynchrony varies randomly from trial to trial (Clifton & Freyman, 1989; Grantham, 1996). "
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