I have heard about this. Some say its Gabriel's Horn, I’m not sure about that....LOL...... It seems to be too elaborate to be a hoax due to the youtube vids being from all over the world……could be something to do with HARRP
http://www.haarp.alaska.edu/
but, I can’t explain why you necessarily hear what HARRP is doing, and who knows exactly what HARRP is doing anyway………another good mystery.
I like the Gabriel scenario, let the games begin !