The study investigated how visually impaired subjects use level and reverberation cues to discriminate distances to sound sources in comparison with a control group of normal vision subjects. Pairs of broadband noise sounds were presented at distances between 1 and 8 m in a reverberant virtual room simulated using an image-source model. Listeners performed discrimination judgments in three conditions: level only (Level-Only), reverberation only (Equalized), and both cues available (Normal). Percentage correct judgement of which sound was closer was measured. Data indicate that level provided more accurate discrimination information than direct-to-reverberant ratio for both impaired and normal vision subjects. When comparing the performance of the two groups, it has been found that the visually impaired show higher performance in using both level and reverberation cues separately, both in the near and further field. Reverberation is shown to become a useful cue for the normal vision group only for sounds in the far field of the listener (over 5 m), while the visually impaired display better performance in the use of the reverberation cue in both near and further field. This shows that the visually impaired have superior ability to process early reflections from indoor environments.
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