Listen to a record of chanting: Tibetan monks, Gregorian chants. If you listen carefully, you will begin to feel the voices become one and create a single pulsating tone. One of the most noticeable effects of several instruments playing or human voices chanting at approximately the same pitch is that you will tend to hear a wah wah wah vibrating effect, or “beat,” as the voices or instruments come into unison and then drift slightly apart. As the tones come into unison, the beat slows down; as the tones drift farther and farther out of key, the beat speeds up.
The frequency of the beat produced by two separate tones equals the frequency of the difference between those two tones. Thus, for example, a frequency of 200 Hz and one of 204 Hz would produce (among other overtones) a “beat frequency” of 4 Hz. Players of guitars, violins, and other stringed instruments use this beat phenomenon when they tune one string to a second string: When the beat slows to zero, the two strings are in tune.
This phenomenon might have remained of little interest to non-musicians were it not for the work of an intrepid explorer of inner spaces named Robert Monroe. Monroefirst came to wide notice in the 1960s with his book Journeys Out of the Body, in which he describes a series of extraordinary experiences that took place while his physical body was asleep.Monroe became interested in finding some way of inducing this out-of-body experience. As he knew that his own experiences had something to do with a feeling of vibrations, he set about to create similar physical vibrations using sound.
Monroediscovered that while scientists had known about “beats” for years, they had not really explored the effects of beats when played over stereo headphones. He found that when the separate sounds were played through separate ears, they created what was called a binaural beat. When pure audio signals of different frequencies are delivered to the brain through separate ears—for example, when a signal of 200 cycles per second enters one ear and one of 204 cycles per second enters the other ear—the two hemispheres of the brain function together to “hear” not the actual external sound signals but a phantom third signal—a binaural beat—which is the difference in frequency between the two actual sound frequencies. This beat frequency is not an actual sound, but an electrical signal that can be created only by both hemispheres of the brain working together simultaneously.
And, as Monroe found, when precisely controlled tones are combined in the brain, a part of it—the olivary nucleus—begins to become “entrained to” or resonate sympathetically to this “phantom” binaural beat, like a crystal goblet vibrating in response to a pure tone, in what is known as a frequency following response. As the olivary nucleus becomes entrained, it sends signals upward into the cerebral cortex that mix with the existing patterns of brain activity there to produce noticeable state changes. AsMonroecontinued his investigations, he found that by using certain frequencies, he could produce a unique and coherent brain state—a state he called hemispheric synchronization.
What binaural beats can provide, then, is a very simple but powerful way of altering brain-wave activity. Combining a signal of 200 Hz in one ear with a signal of 210 Hz in the other produces a very subtle, gentle vibrating effect, yet it is stimulating the listener’s deep brain at a 10 Hz frequency state. This gentle technique is far less intrusive or irritating than simply banging a drum in the listener’s ear ten times per second. Thus binaural beats can provide a method for rapidly, subtly (even subliminally) altering brain-wave activity into a more organized or coherent brain state and boosting listeners into specific altered and expanded states of consciousness.
What’s more, as electroencephalogram (EEG) researchers have found, these carefully tuned binaural beats can be superimposed, layer upon layer, producing complex sound matrices with powerful state changing effects. Certain frequency combinations, for example, can produce powerful alpha activity, while other combinations effectively suppress alpha and increase synchronous theta and beta. Other combinations produce a state that combines profound relaxation with heightened alertness—a stateMonroecalls “mind awake/body asleep.”
There’s no doubt these beats have profound brain-altering effects. A large body of research has proven their effectiveness in a variety of applications ranging from accelerated learning, to pain reduction, to boosting immune function. One recent study atMemphisStateUniversityby Dale Foster, Ph.D., used EEGs to measure the amount of alpha brain-wave production in subjects using biofeedback EEG training, subjects hearing alpha binaural beats, subjects using a combination of biofeedback and binaural beats, and a control group. Foster’s conclusion: “An interactive effect was found in which the group with both alpha binaural beats and alpha biofeedback produced more treatment alpha than the group with alpha biofeedback alone.” Additionally, a majority of the subjects receiving both binaural beats and feedback reported “being able to control alpha production via their focus on the alpha binaural beats.” Foster concluded that “the combination of alpha frequency binaural beats and alpha brain wave feedback resulted in significantly more alpha production than alpha brain wave feedback alone.”
Other evidence is emerging fromWashingtonstate educator Jo Dee Owens that for older people, the combination of delta binaural beats with high beta beats can have an extraordinary vitalizing effect. Binaural beats are used on a variety of widely advertised audio tapes and compact discs (CDs). You may have seen ads for the best-known of these tapes, which describe the process as “ultra meditation,” “high-tech meditation,” and so on.
While some of these tapes are effective, many are not, because they assume that, simply by creating binaural beats at a certain frequency and sending them to the brain through the ears, they can directly trigger brain-wave activity at the same frequency. But as EEG researchers such as F. Holmes Atwater have noted, this “classical evoked potential” concept is “flawed from the onset.” Binaural beats simply do not work that way.
EEG research shows that binaural beats do not directly alter EEG activity; rather they actually are “heard” in the lower auditory centers—in the olivary nucleus of each hemisphere, deep inside the brain. There the actual oscillations in response to binaural beats can be measured directly. To produce the desired state-change effects throughout the cortex, binaural beats must be combined in a highly specific mix that makes use of what Atwater calls the “audio-encephalographic interferometry effect.” In essence, the binaural beat oscillations must be mixed via the olivary nucleus with existing brain-wave patterns to create “interference” patterns or wave combinations that produce higher-order patterns, out of which emerge the expanded states of consciousness.