The basic gist of brain wave entrainment is organic resonance. When the brain receives audio signals, it slowly tunes its own frequency to match the frequency it is receiving. So, if you want to see 33 Hz on your EEG, you play a 33 Hz tone in your ear.

This would all be nice and straightforward, were it not for the fact that the human ear doesn't generally pick up frequencies under 16 Hz. With no way to pick it up, the signal isn't relayed to the brain, and you're out of luck. Unfortunately, most of the "fun" frequencies are beneath the 16 Hz threshold. It becomes necessary to trick your nervous system into perceiving lower frequencies.

Of course, the human ear might be unable to relay "fun" tones for a good reason! Imagine what would happen if you went into a trance every time you heard a low whale song ... you just might end up falling asleep and drowning at the beach.

The technique for feigning these lower frequencies is the binaural beat. The theory goes that if you play a 25 Hz frequency in one ear, and a 18 Hz frequency in the other, the human nervous system will try to resolve the input from both ears as one picture. The big picture ends up containing a 25 Hz tone, an 18 Hz tone, and a new "interpreted" 7 Hz beat wave.

For those interested in experimentation, there are programs available for both Windows and Linux that will allow you to easily generate binaural beats.

For Windows experimentation in brain wave entrainment, you might try Cool Edit by Syntrillium Software. If you're the free software type, you'll find plenty of free keys to "register" it.

Linux users can generate binaural beats with packages named 'SBaGen' and 'rhybag', available at

Some reported frequencies include:

1-3 Hz   Delta Range: deep, dreamless sleep, trance state, non-REM sleep.
1.0 Hz   Feeling of well-being, pituitary stimulation to release growth hormone.
2.5 Hz   Pain Relief, relaxation. Production of endogenous opiates.
3.4 Hz   Sound sleep.
3.5 Hz   Accelerated language retention.
4-7 Hz   Theta Range: fantasy, imagery, meditation, drowsiness.
6.0 Hz   Long term memory stimulation.
7.0 Hz   Mental and astral projection.
7.5 Hz   Entry into meditation.
7.83 Hz  Earth Resonance, "Schumann Resonance."
8-13 Hz   Alpha Range: relaxed, tranquil, inward focus.
8.0 Hz    Past life regression.
8.3 Hz    Visual images of mental objects.
9.41 Hz   Pyramid frequency.
9.6 Hz    Frequency associated with the earth's magnetic field.
10 Hz     Release of serotonin. Try it for hangovers and jet lag.
10.5 Hz   Healing of body, firewalking, stimulation of the immune system.
13-30 Hz  Lower Beta Range: Normal wakefulness.
14.0 Hz   Awake and alert.
16 Hz     Threshold of human hearing.
18-22 Hz  Beta: outward awareness, sensory input instead of internal.
27.5 Hz   Lowest note an a piano.
38 Hz     Endorphin release.
63 Hz     Astral projection.
70 Hz     Mental and astral projection.
111 Hz    Beta endorphins and cell regeneration.

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