Effects of room reflectance and background noise on perceived auditory distance.

Perceptions of egocentric auditory distance were investigated within an environment for which the reverberation time could be systematically varied without changes in the size or shape of the room. Two levels of wide-band background noise, differing by 20 dB, were used as a masking stimulus. Target sounds were presented from distances between 0.75 and 6.0 m and verbal reports of distance were collected from 288 listeners in two separate experiments. Changes in physical distance produced variation in reported distance in each configuration. Reported distance was generally proportional to real distance, but considerably underestimated when room reflectance was low. When room reflectance was high (T60 approximately 1.7 s for the range of frequencies used), initial reports of distance were often overestimates; upon repeated presentation, judgments in the high reflectance room became more nearly veridical. The effect of increasing the background noise level was to decrease the perceived distance. These findings are in accord with expectations based upon the importance of reverberation cue(s) to distance and upon previous analyses from this laboratory.