From just below, the noise is about twice as strong as that of a high voltage line but really less stressful.
Here is a small summary of the CLER (Renewable Energy Liaison Committee)
The sound pressure level decreases with distance. The further away from the source, the lower the perceived noise (which is valid for any sound source)
at 10 m of the source, the sound level loses 30 dbA
at 20 m of the source, the sound level loses 35 dbA
at 30 m of the source, the sound level loses 40 dbA
at 100 m of the source, the sound level loses 50dbA
Here is a small table of the sound level of a wind turbine according to the wind speed
Wind speed (km / h) / Ambient sound level (dB (A))
18 / 38
25 / 41
32 / 45
40 / 49
47 / 53
54 / 56
And after ? : the sound level of a wind turbine stabilizes when the wind reaches a certain speed. Beyond this speed, the sound level of the wind continues to increase while that of the wind turbine remains stable. The wind noise then covers that of the wind turbine.
The decibel scale is used to position a certain number of known noise emissions in relation to the average noise emitted by a wind turbine located at a distance of 250 m
10 dB falling leaves
15 dB whispers
30 dB Interior of a bedroom
40 dB wind turbine
50 dB Interior of a house
70dB Office
80dB Interior of a car
90 dB Stereo Music
100 dB Interior of a factory
120 dB Jackhammer
150 dB Jet aircraft
What happens when there are several wind turbines?
The increase of the sound level is in no way proportional but logarithmic. This means that the presence of two identical sound sources does not lead to a doubling of the perception of the loudness. Thus a person placed at an equal distance of two identical sound sources will perceive an increase in the auditory level of 3dB. Four identical sources will increase the level of 6dB.