Perception and Analysis of Selected Auditory Events with Frequency-Dependent Directions

Relatively little is known about complex auditory events caused by multiple simultaneous sources. In order to gain insight into this topic, the perception of wide-band (200-1179-Hz) noise and click train stimuli was examined with subjective tests focusing on perceived spatial distribution. By reproducing different frequency bands of the stimuli from loudspeakers at different azimuth directions, the spatial content of the overall stimulus was varied in 15 test cases. The subjects were required to indicate those loudspeakers that they perceived as radiating sound in each case. The results suggest that the highest and lowest frequencies of the stimuli were more perceptually significant than the middle frequency region. The test cases were never perceived as being more than half the actual width of the source ensemble. The order of the critical-band signals in the loudspeaker setup had a minor effect on the overall width. When a click train stimulus was used instead of continuous noise, the perceived width was reduced significantly. Cross-correlation-based auditory modeling techniques were also examined for their ability to predict the subjective results and were found to be not entirely suitable for the purpose.