Re:There's a Persistent Hum in Windsor, Ontario, and No One ...
by Johnythree on Tuesday February 20, 2018 @09:56PM
(#16426470)
You can't do this with a sine wave. It's impossible to exclude waves caused by reflections.
The sound pressure wave is picked up by one, then some few microseconds later, it appears on the other(s) a few centimeters away.
This is pretty straightforward with ordinary sounds that dominate the signal. You could pick out the wire which was struck in a piano, and even the nodes and harmonics along its length.
It gets more difficult at lower frequencies and with quieter signals, which precisely describes this exact situation.