Discrimination of relative distance in the auditory modality: the success and failure of the loudness discrimination hypothesis.

Difference limens for auditory distance discrimination were determined using the method of limits. Eight untrained subjects were tested across a wide range of distances (49 to 4876 cm) using broadband noise sources. For sources in excess of 304 cm, the Weber ratios observed approximated the function predicted by the inverse first power loss equation. At the longer distances, the subjects appear to be judging distance on the basis of the loudness difference cue. At the shorter distances (49 to 304 cm), the Weber ratios were considerably larger than would be predicted from the inverse first power loss equation. In this range, distance discrimination becomes increasingly degraded as the referent source approaches the subject.