On the annoyance caused by impulse sounds produced by small, medium-large, and large firearms
article
A laboratory study was designed in which the annoyance was investigated for 14 different impulse sound types produced by various firearms ranging in caliber from 7.62 to 155 mm. Sixteen subjects rated the annoyance for the simulated conditions of (1) being outdoors, and (2) being indoors with
the windows closed. In the latter case, a representative outdoor-to-indoor reduction in sound level was applied. It was anticipated that the presumed additional annoyance caused by the heaviness of the impulse sounds might be predicted from the difference between the C-weighted sound exposure level (CSEL;LCE) and the A-weighted sound exposure level (ASEL; LAE). In the outdoor rating conditions, the annoyance was almost entirely determined by ASEL. The explained variance, r2, in the mean ratings by ASEL was 0.95. In the indoor rating conditions, however, the explained variance in the annoyance ratings by (outdoor) ASEL was significantly increased from r2=0.87 to r2=0.97 by adding the product (LCE2LAE)(LAE2 a) as a second variable. In combination with a 12-dB adjustment for small firearms, the present results showed that for the entire set of impulse sounds rated indoors with windows closed, the rating sound level, Lr , is given by Lr5LAE +12 dB1+beta(LCE-LAE)(LAE-alpha), with alpha=45dB and beta = 0.015 dB-1. For the outdoor rating condition, the optimal parameter values were equal to alpha=57 dB and, again, beta=0.015 dB-1. In validation studies, in which the effects of the present rating procedure will be ce compared to field data, it has to be determined to what extent the constants a and b have to be adjusted. (A)
the windows closed. In the latter case, a representative outdoor-to-indoor reduction in sound level was applied. It was anticipated that the presumed additional annoyance caused by the heaviness of the impulse sounds might be predicted from the difference between the C-weighted sound exposure level (CSEL;LCE) and the A-weighted sound exposure level (ASEL; LAE). In the outdoor rating conditions, the annoyance was almost entirely determined by ASEL. The explained variance, r2, in the mean ratings by ASEL was 0.95. In the indoor rating conditions, however, the explained variance in the annoyance ratings by (outdoor) ASEL was significantly increased from r2=0.87 to r2=0.97 by adding the product (LCE2LAE)(LAE2 a) as a second variable. In combination with a 12-dB adjustment for small firearms, the present results showed that for the entire set of impulse sounds rated indoors with windows closed, the rating sound level, Lr , is given by Lr5LAE +12 dB1+beta(LCE-LAE)(LAE-alpha), with alpha=45dB and beta = 0.015 dB-1. For the outdoor rating condition, the optimal parameter values were equal to alpha=57 dB and, again, beta=0.015 dB-1. In validation studies, in which the effects of the present rating procedure will be ce compared to field data, it has to be determined to what extent the constants a and b have to be adjusted. (A)
Topics
TNO Identifier
10575
Source
Journal of the Acoustical Society of America, 109(1), pp. 244 - 253.
Pages
244 - 253
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