1) I've stood directly underneath a 1MW turbine in the middle of a large wind farm on a windy day. There wasn't much noise at all, just a light whoosh... whoosh... whoosh.... I don't know where this concept that wind turbines are "terribly noisy" comes from, but it doesn't at all match my experience.
I've held a megaphone in front of my mouth and spoken into it. All I heard was my own regular voice, therefore I don't believe they work as advertised. In other words, it's all about direction.
I've also been visiting a house about 1.5km(1 mile) away from the nearest wind turbine, with the noise disturbance inside the house being at such a degree that I couldn't believe our government could let this happen. When the noise hits them, the residents can't sleep and neither would you in similar circumstances.
The issue seems to be mostly coming from the low frequency noise forming from the air pressure of the wing hitting the tower after the wing has passed. It seems to be very directed - directly sideways of the turbine.
Another contributing factor is weather. Certain conditions can cause noise that is emitted on a rising angle to curve back downwards. When these rare weather conditions are met, we've found people much father away complaining about the noise while the residents much closer had no issue with it.
Often there's more going on than immediately meets the eye.