Has anyone heard of this? From the quick research it's frequency in various tones that mess with your brainwaves. There have been studies on binaural beats. You can find some of the frequencies on YouTube but the mp3's/cd's are very expensive. [video=youtube;d1akBw6G180]http://www.youtube.com/watch?v=d1akBw6G180[/video] The Gates Of Hades, also called The Gates Of Hell, is the most popular and looks downright unpleasant.