| Abstract #103, Date 2/14/99, Session E4, Poster (B71) |
| Localization of near-field sources in a reverberant room |
| S.G. Santarelli, N. Kopco, *B.G. Shinn-Cunningham (Boston University Department of Cognitive and Neural Systems) |
Subjects were asked to point to the position of sound sources within one meter of the head while seated in a medium-sized, echoic classroom. These localization results are compared to results from a previous study that used an identical procedure (but a different set of subjects) in anechoic space. Overall, localization in the reverberant room is worse than observed in the anechoic conditions (a surprising result, given that, for sources near the head, the reverberant energy is weak relative to the direct sound reaching the ears). In order to understand these results more fully, gross interaural time difference (ITD) and interaural level difference (ILD) cues were estimated for near-field sources in anechoic space using a simple model. This analysis is especially interesting since iso-ITD and iso-ILD surfaces in the near field differ from the "cone-of-confusion" (iso-binaural cue) surface that occurs for sources relatively far from the head. To analyze response errors for each subject, the estimated ITD and ILD values are found for both source and response positions. From this analysis, localization errors are estimated in units of binaural cues (ITD and ILD) and non-binaural cues. This analysis implies that reverberation does not affect interaural time and interaural intensity localization errors in the same way. It also appears that there are consistent subject differences in both binaural abilities and in non-binaural localization abilities, and that these differences capture much of the intersubject variability observed. |