Subjective response for impulsive sound of firearms in Korea

This research presents a laboratory study about a subjective response of impulsive sound caused by firearms in the field. The signals were sampled from outdoor noise and their levels range from 40 to 70 dB(A). The tests of firearms sources and pink-noise used as an object and a reference source were carried out separately. The attenuation of the signals (geometrical divergence, atmospheric absorption and ground) was considered with the application of a finite impulse response (FIR) filter. The evaluation method adopted a semantic differential method (7-point scale) and sources were provided to the listener by three methods that consisted of Bottom-Up, Random, and Top-Down methods and by an interval of 5 or 10dB. The result from Bottom-Up method has been found to give higher subjective response than the other two methods. But the curves of Random and Top-Down have a crossing point. Subjects who selected 6 or 7 point were classified as %HA. Subjective mean response rating appeared linear function and %HA appeared a sigmoid function. Subjective response of small caliber firearms was generally higher than that of large caliber firearms, because the sound of small-firearms included more high-frequency energy than that of large-firearms. The result by has been combined response of the three methods for the object sound was executed by regression analysis. The results are shown as the following equation respectively. : MR=-1.9571+0.1061*L_AE, %HA=100/(1+exp(-(L_AE-68/6207)/7.102)).