The test stimuli recorded during a recent field study consisted of 16 sounds, each presented at 4 peak noise levels. Two helicopters and a fixed-wing aircraft were used. The impulsive characteristics of one helicopter were varied by operating at different rotor speeds, whereas the other helicopter, the noise of which was dominated by the tail rotor, displayed little variation in blade-slap noise. Thirty-two subjects made noisiness judgments on a continuous, 11 point, numerical scale. Preliminary results indicate that proposed impulsiveness corrections provide no significant improvement in the noisiness predictive ability of Effective Perceived Noise Levels (EPNL). For equal EPNL, the two categories of helicopter stimuli, one of which was far more impulsive than the other, showed no difference in judged noisiness. Examination of the physical characteristics of the sounds presented in the laboratory highlighted the difficulty of reproducing acoustical signals with high-crest factors.
A laboratory study of the subjective response to helicopter blade-slap noise
1978-12-01
Report
No indication
English
Subjective evaluation of helicopter blade slap noise
NTRS | 1978
|Helicopter Noise Blade Slap. Part 2 Experimental Results
NTIS | 1972
|Helicopter noise - blade slap ; Pt. 2: Experimental results
TIBKAT | 1972
|