Human and Community Response to Military Noise. Results From Field-Laboratory Tests of Small Arms, 25 mm Cannons, Helicopters, and Blast Sounds.

Abstract : The study reported here utilized paired-comparison tests with listeners in real houses to evaluate human response to test sounds from one of four categories of military sources: (1) small arms fire, (2) 25 millimeter (mm) cannon fire, (3) helicopters, and (4) large blasts. The control sound sources were either a wheeled vehicle or white/pink noise. These tests, performed at Aberdeen Proving Ground, MD, compliment similar tests in Germany (Schomer et al. 1994). The Germany tests were performed at the German Military installation at Munster and used tracked vehicles, small arms and large blasts as the test sound sources. These tests substitute helicopters or 25 mm guns for the tracked vehicles used in Germany. Where comparable, the new results are similar to the Munster results. For wheeled-vehicle control sound, the maximum value of the small arms penalty was of the order of 10 dB for the additional annoyance of the impulsive sound; for the 25 mm weapon, the penalty was more like 15 dB. Surprisingly, the helicopter penalty was virtually zero. For the same A-weighted sound exposure level (ASEL) of control sound, the wheeled-vehicles and pink-noise control sounds yielded annoyance-penalty results which differed by about 10dB. The relationship between the CSEL of a large-amplitude impulsive sound and the ASEL of its equivalently-annoying control sound was level dependent with a slope of the order of 1:2; i.e., a I dB change in blast-sound CSEL corresponded to about a 2 dB change in the ASEL of the equivalently-annoying control sound. With outdoor acoustical measurements, the annoyance (indoor subjects) generated by a large-amplitude impulse sound and its equivalently-annoying control sound were equal when the CSEL of the impulse sound and the ASEL of the control sound were each about 103dB. (AN)