Psycho-acoustic characters of relevance for annoyance of wind turbine noise

The knowledge of annoyance and perception of wind turbine noise is limited, although some previous studies have found that the relationship between the equivalent noise level and annoyance was weak. The hypothesis for this study was that different sound characters in the noise not fully described by the equivalent noise level, are of importance for annoyance and noise perception. In total, 25 subjects were exposed to five different wind turbine noises at the level of 40 dB L-Aeq. Subjective ratings of annoyance, relative annoyance and for how long they were aware of the noises were carried out after 10 min exposures. This was followed by 3 min exposures where perception and annoyance of 14 psycho-acoustic descriptors were evaluated. The results showed that the rating of annoyance, relative annoyance and awareness was different between the wind turbine noises, although they had the same equivalent noise level. A psycho-acoustic profile was obtained for each noise, which subjectively described the most and the least annoying sound parameters. None of the psycho-acoustic parameters, sharpness, loudness, roughness, fluctuation strength or modulation could explain the differences in annoyance response. (C) 2002 Academic Press.