[jmb99]

A buddy of mine has two on his property, one within a stones’ throw of his house and barns. Not only does the sound not drive him insane, I couldn’t hear it (at all), nor any of the other ~600 in the area.

[codr7]

It depends a lot on geography and (obviously) winds in the area.

I can assure you that it's very real, and very harmful on a daily basis.