Below is copy/paste:

In 1973, Dr. Gerald Oster discovered something really interesting. If we hear different frequencies in each ear, the brain resonates at a frequency that is the difference between the two tones. A perceptual integration of the two signals takes place, producing a third “beat” frequency. This third beat, perceived as a fluctuating rhythm, is called a binaural beat.

Okay, here’s the cool part. The fluctuating rhythm of the frequencies as they oscillate in our ears and brains actually alters our brains waves. Depending on the frequency of the binaural beat, the effect may be relaxing or stimulating. By aiming for the delta or theta waves associated with whole-brain integration, we can actually create optimum conditions for our best thinking and highest creativity.

Since Dr. Oster’s discovery, many researchers and entrepreneurs have developed tapes and CDs to capitalize on the binaural beat concept to create motivation or relaxation programs.

We listen to these CDs, and as we do so, our brain waves are gradually locking in resonance with what we’re hearing. And the best part is that our brains do this automatically. It takes no effort at all.