Re:The U.S. wind industry now employs more than 100K people
by mappu on Saturday April 22, 2017 @11:12PM
(#14176256)
The charts extend only up to ~5Hz and the intensity already decreased a lot. Human hearing range commonly doesn't start until 20Hz. Do you have charts including higher frequencies?
Re:The U.S. wind industry now employs more than 100K people
by randomdata on Sunday April 23, 2017 @10:08AM
(#14178200)
I already asked the grandparent, but received no response[1]. What make/model generated that profile? And how does it compare to the same measuring setup used on other units? While they may all look the same at a distance, you can find vast design differences between them when you start to look closely. It seems unlikely that they would all generate the exact same noise.
To put it another way, a car on the NASCAR circuit looks a lot like a road suitable car anyone can buy at the dealer's lot, but the sound is completely different. It pays to be specific.
Just out of curiosity here's the noise profile (spectrogram) of a turbine at 1,37 km (0.85 miles), measured inside a home, where we can see the base frequency and several harmonic multiples:
http://i.imgur.com/m31hhR5.png
Here's the same turbine at 5km (3.1 miles), again inside a house, where the turbine is shut off at 11 a.m.:
http://i.imgur.com/pRJeunj.png
As we can see this low frequency noise can travel very long distances, and when you have wind farms with multiple turbines they can even create interference patterns, that could amplify the problems further.