Out of curiosity, what make/model are they? I rent some land in the middle of a wind farm, one of which one is standing on that particular ground, and I don't know what there really is to hear.

I expect it is a particular manufacturer or unit, and quite possibly one built a long time ago, that is causing the trouble that some experience. But I haven't been able to track down which one. Sadly, it seems most just see 'tall white things with blades' and think they are all identical, which makes getting reliable information fairly difficult.