I'm not sure to what specific beats you've been listening to but they surely did "work". I listened to a few hemi-sync beats some time ago (http://www.hemi-sync.com/) and they've brought me the worst nightmares I've ever had. On the next they I got sick. I've also talked to people who said they've had OBE (http://en.wikipedia.org/wiki/Out-of-body_experience) after listening to those beats. This never happened to me though. Just the nightmares. I guess it really depends on your current state, in what frequency these waves put your brain in, etc. So it's highly individual.