I've messed around with binaural beats, but not enough to actually do anything with it. I can tell it definitely allows for a trance like state easier.

I have used a sensory deprivation tank, and I have to say wow. Those things are amazing. Im actually in the planning stages of building my own. I just don't have a place to put it yet and have to figure that part out. However there are a few places near me where you can pay around $40 per hour. I recommend anyone interested go for an hour and a half. It's way better. After enough times I believe I could achieve an obe or a dmt like state just using the tank.