== it works (but is no magic) == 
 There was a common wave editing program that could do alteration to a sound track to add binaural beats to a waveform. I've tried it, and it works, but it's not much of a magic behind it. 
 My experience is that it works if you select a comfortable audio track to relax to which is about 5-10 minutes. Then make a binaural beat to slowly turn down the mix frequency so that 
 delta frequencies are inducted only at half way and the inducted frequency slightly drops towards that goal. Finally, listen to it in a relaxed position (e.g. lying on a sofa with 
 headphones on). You should feel a comfortable relaxation as soon as the sounds seem to stop being disordinate between the stereo speakers and seem to blend into a common rythm. 
 This is of course no magic: You'll need a tune to which you can relax anyways. You'll need to be in a position to relax anyways. You'll need to take the time to relax. And it won't 
 do wonders (e.g. having only slept a few hours a night and waiting for the magical refreshing effect). But in the aforementioned circumstances it helps quite a bit to refresh, at least for me.