Binaural (spelled correctly) beats or tones are simply audio sounds emitted at different frequencies, the effect is useless unless one speaker or head phone ear piece is emitting one frequency and the other emitting another frequency ranging between 30 or less hertz and the frequency being emitted by either speaker or head phone must be equal or less than 30 hertz, both frequencies must be below 1,000 hertz for the binaural beat effect to be noticeable.
The use of these beats or tones vary depending on purpose, person, and other such variables. However the general purpose is to elicit an affect either in mood, emotion, or sensation by the stimuli of the frequencies being used. The affects that each binaural beat or tone will have will vary by the frequencies being used.
Anywho I am by no means an expert in binaural beats, tones, and frequencies and I have only recently been researching the subject, however I use them often in my meditations and trance work and I have experimented with the ones I use for various purposes in my workings, trance work, and meditations and so far I have found they work effectively for my needs. But like I said it all varies for each person and each binaural beat etc. I hope this helps and good luck.