I live in Invenergy's California Ridge Wind Farm near Armstrong. To educate people about turbine noise, let me offer firsthand information.
The wind speed, time of day — night being the loudest — plus rotation speed of the turbine blades combine to produce a disruptive noise level.
When the turbine blade takes four seconds to make a rotation the loudest noise is produced, including low frequency noise generating a humming, droning sound.
In contrast, if the rotation takes five to six seconds, the noise level drops. To measure rotation speed, count the seconds it takes for the tip of the blade to make a complete 360 degree revolution.
When investigating, do not make the mistake of driving under the turbine to listen as the noise is produced from above and heard peripherally.
Low frequency noise can affect people differently — like fingernails on a chalkboard. This may not bother one person, but it may negatively impact another. When turbines are at their noisiest, it is like experiencing motion sickness and/or a feeling of anxiety.
Contrary to what Invenergy's lawyer, Mike Blazer, said in a recent News-Gazette article, I am pleased with the local sound specialist. Blazer indicated I was "not comfortable" with this person.
This is untrue. In fact, I contacted the same sound specialist requesting a study. However, he was under contract with Invenergy, creating a conflict of interest.
I hope this answers some readers' questions. Readers who have more can call me. I'm in the phone book.