posted on Jan, 13 2012 @ 03:14 PM
reply to post by kdog1982
Ducting is an EM phenomenon (as it says, handy for long range radio communication). This is the principle behind the Earth's Schumann resonance --
the fact that the ionosphere ducts mostly ELF radio waves, which then circle the globe at specific frequencies (the fundamental being ~7.48 Hz, for a
wavelength equal to the Earth's circumference).
Obviously, EM waves are inaudible. I was considering the possibility that these ducted waved may be causing physical vibration, which we are
perceiving as sound, but I don't think it's very likely. The EM waves would have to have a ridiculously large amplitude to create such an audible
vibration in the air.
What I'm suggesting (and attempting to evidence with my experiment) is the ducting of sound. It's the exact same principle, just with sound waves
instead of radio waves.