[mattjaynes]

The youtube video creator addresses this in the description and comments:

"the base frequency is 183.58 and the "binaural beat" frequency is 40hz - meaning the difference in the left ear and right ear is 40hz. The left ear plays 183.58 and the right ear plays 223.58hz the difference being 40hz. "

[louthy]

Ah, sorry, I missed that. Still, I maintain that's different to what's stated in the article of "40 hertz tone". Which to me means a 40hz sine wave.

Perhaps the binaural effect does have some benefits, but personally I was struggling to listen to that video for more than 30 seconds or so without feeling both mildly sick and annoyed at the same time! However, I've been listening to the 40 hertz tone from the link I posted above for a good 10 minutes now without any bother. It's quite relaxing after a while actually.