Dien, I'm trying to find out more about entrainment, which the site I'll post in a second says is used in physics. Is this true?

It sounds like the same type of process used in Biofeedback, with a different label attached to it, to help one enter various brainwave states.

Would appreciate any feedback on this process or related info.

The site is http://www.optimindzation.com/index1.html

Many thanks!

Sandi Bowman