Brainwave entrainment / Binaural beats

Brainwave entrainment or "brainwave synchronization," is any practice that aims to cause brainwave frequencies to fall into step with a periodic stimulus having a frequency corresponding to the intended brain-state (for example, to induce sleep), usually attempted with the use of specialized software. It purportedly depends upon a "frequency following" response on the assumption that the human brain has a tendency to change its dominant EEG frequency towards the frequency of a dominant external stimulus.[citation needed] Such a stimulus is often aural, as in the case of binaural or monaural beats and isochronic tones, or else visual, as with a dreamachine, a combination of the two with a mind machine, or even electromagnetic radiation

Binaural beats or binaural tones are auditory processing artifacts, or apparent sounds, the perception of which arises in the brain for specific physical stimuli. This effect was discovered in 1839 by Heinrich Wilhelm Dove, and earned greater public awareness in the late 20th century based on claims that binaural beats could help induce relaxation, meditation, creativity and other desirable mental states. The effect on the brainwaves depends on the difference in frequencies of each tone, for example, if 300 Hz was played in one ear and 310 in the other, then the binaural beat would have a frequency of 10 Hz.[1][2]

The brain produces a phenomenon resulting in low-frequency pulsations in the amplitude and sound localization of a perceived sound when two tones at slightly different frequencies are presented separately, one to each of a subject's ears, using stereo headphones. A beating tone will be perceived, as if the two tones mixed naturally, out of the brain. The frequencies of the tones must be below 1,000 hertz for the beating to be noticeable.[3] The difference between the two frequencies must be small (less than or equal to 30 Hz) for the effect to occur; otherwise, the two tones will be heard separately and no beat will be perceived. An on-line sound example of a sound with binaural beats can be found here.


Binaural beats are of interest to neurophysiologists investigating the sense of hearing.[4][5][6][7]

Binaural beats reportedly influence the brain in more subtle ways through the entrainment of brainwaves[3][8][9] and have been claimed to reduce anxiety[10] and provide other health benefits such as control over pain.

I've become increasingly interested in brainwave entrainment after reading the following article - http://www.washingtonpost.com/wp-dyn...-2005Jan2.html

I'm particularly intrested in the gamma wave frequency and how it may affect our consciousness, levels of awareness and sense of perception during meditation.

Does anyone here have experience with brainwave entrainment ? I'd like to hear about it.

Also if you have any usefull links to offer me i'd appreciate it as i don't know much about the topic yet. I had a fleeting interest in it years back but kinda snuffed at it though there seems to be gathering evidence for it.