THE EFFECTS OF DURATION AND BACKGROUND NOISE LEVEL ON PERCEIVED NOISEINESS
BOLT BERANEK AND NEWMAN INC VAN NUYS CA
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Judgment tests were conducted to investigate the effect of duration and background noise on the perceived noisiness of sounds. The tests were conducted in an anechoic chamber with 18 subjects. Aircraft noise recordings were employed in the background level test, and the results indicate that the presence of background noise reduces the judged noisiness of an aircraft flyover. The duration tests utilized stimuli with two different time patterns and various spectrum shapes over a range of durations from 4 to 64 seconds. Combining the results of these tests with those of a previous study provided duration information over the range from 1-12 to 64 seconds. These data suggest that the dependence of perceived noisiness on duration might well be a function with a continuously decreasing slope, varying from -6 to -2 PNdB per doubling of duration over the range of durations tested. For practical purposes, we have approximated the data by straight-line segments for various ranges of duration.