Binaural and Monaural beats used for entrainment are
formed by sending
Binaural Beats:
Binaural beats are by far the most commonly
used entrainment method, although not the most effective. The reason for their
popularity is simply due to their initial use in cognitive and neurological research since Gerald Oster in the seventies and then further study by those such as Robert Monroe of the Monroe Institute.
Because the tones have to be created in the brain, headphones are required for binaural beats. Otherwise they become monaural beats before reaching your brain; while this can still lead to entrainment, some methods are better than others depending on the application and the intended result. Binaural beats have a generally accepted range from .235 to 26.25hz although they have been used successfully in the higher Beta and Gamma states. One major benefit of binaural beats is that in order to create a binaural beat, the brain must use both hemispheres (both the left and the right) which can result in what is called "hemispheric synchronization".
Monaural Beats:
Monaural beats are similar to binaural beats
in that two signals are combined however the signals combine in the air before
reaching the brain, whereas binaural beats are created in the brain. While
monaural beats are more effective at entrainment than binaural beats, they
become less effective below 4hz. Also, monaural beats require less noise so that
the beats can be heard.
Isochronic Tones:

Brainwave States

|
HyperGamma
100 - 200hz
|
|
Lamda
200+hz |
|
Epsilson
< 0.5hz |
*As noted by Dr. Jeffrey D. Thompson at the
Center for Neuroacoustic Research