Auditory Perception in an Open Space: Detection and Recognition

Report No. ARL-TR-7305
Authors: Kim F Fluitt; Timothy J Mermagen; Szymon Letowski; Tomasz Letowski
Date/Pages: June 2015; 66 pages
Abstract: The purpose of the current study was to investigate the effects of distance and meteorological conditions on detection and recognition of, and distance estimation to, various sound sources spread across a large open field. This report presents results of the detection and recognition tasks. Both acoustic (target sound and noise level) and meteorological (wind direction and strength, temperature, atmospheric pressure, humidity) data were collected for each experimental trial. Twenty-four subjects participated in this study. Eight various sounds delivered from 6 test loudspeakers were presented to the listeners. The results indicate that in most cases as soon as a sound is detected, it is recognized. In most cases both the detection and recognition of sound sources declined rapidly at distances greater than approximately 100–200 m. The main effects of weather conditions and environmental noise are strongly correlated. Some expectations of sound propagation were not observed during data collection; specifically, sounds were more easily heard in the afternoon as opposed to the morning, which meant that participants detected and recognized sounds more accurately in the afternoon than in the morning. This was most likely attributed to the varying effects of temperature, humidity, and background noise in relatively very hot listening conditions. However, the overall performance of participants was very close to the results predicted by in-house software that modeled human detection of sounds.
Distribution: Approved for public release
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Last Update / Reviewed: June 1, 2015