This is awesome! Not a prank!
But before anything else, you need to use headphones for this to work. Make sure there is no noise around, close your eyes and turn the volume up a little bit. You can hold and press headphone on your ears for better hearing, play it and enjoy this impressive audio work.
CREDITS: Finally the origin of the embedded audio clip has been found. This amazing audio clip was created by QSound Labs ( http://www.qsound.com ) as a demonstration of Binaural audio technology.