yes i think that is the same thing im talking about,
but what is the wierd energy build up sound about?. howcomes it is constant and also is hard to do for long periods of time?.
if you do it while your in a meditation state, its alot easyer to clear the mind of all thoughts, just concerntrate on the sound and you will find its easy to keep a blank mind,
i dont know if its a good idea to try and do it until you pass out though, i dont do it past my limitations i stop when it gets uncomfortable,
it might be dangerous, im glad to hear that others can do it though.
peace,