posted on Sep, 22 2012 @ 01:30 AM
I pick up similar sounds through my audio equipment due to electrical interference caused by wired grinders/drills, sometimes trough the power lines
and sometimes because they are close enough to get picked up by mics and pick ups, they never are as consistent or raise/drop pitch as regular as
shown in the clip, but varies depending on what they are cutting or grinding, never heard a signal that strong before and never heard it picked up
through radio before, strange.