Near-field localization in echoic rooms

The current study examines the ability of subjects to indicate the distance and direction of sources within 1 m of the head in a medium-sized, echoic classroom. Two conditions were tested in the same group of subjects. In the first, subjects were seated in the center of the room, relatively far from any hard reflective surfaces. In the second condition, subjects were located at the same position in the room, but a 12×4 enamel-covered wallboard was positioned next to the listener to create an additional artificial wall approximately 6 in. from the left ear of the listeners. The initial hypothesis was that previous localization results from tests in anechoic space would be nearly indistinguishable from the results in the first condition, since for sources near the head, the direct-to-reverberant energy ratio in this first condition would be very large. However, it was believed that the addition of a single, short-latency echo might bias some localization judgments, particularly judgments of distance and elevation. Instead the results indicate that localization accuracy and variability are comparable for the two echoic conditions, but that both measures of localization ability are worse in echoic conditions than in anechoic conditions.