Have you ever heard of binaural beats? Binaural beats are an interesting phenomenon that occurs when you play two sound waves that are very, very close in frequency but not identical together. You get a phenomenon called beat frequencies between the two sound waves. As it turns out, if you play these two audible frequencies separately, one into each ear, your brain will resolve the difference between the two and “hears” the beat frequency even though it isn’t there. This “allows” you brain to hear frequencies normally below the normal human hearing frequencies.

What’s odd—and exciting—is that these perceived beat frequencies cause your brain to do some peculiar things. The imaginary beat frequency tricks your brain into taking on the frequency of the beat frequency. People are using this idea to modify their mood and mental state. These beat frequencies can work so well that you can recreate the effects of meditation, happiness and even the effects of certain drugs, all without leaving the safety zone of your own trusty headphones.

While interesting scientific phenomena make for a half-decent casual read, the really intriguing part from a lifestyle point of view is: does this really work? Do binaural beats really alter your brain state, sometimes dramatically? It works surprisingly well for most people. At first you just hear the discrete tones, but after a while (if you relax), the tones start to disappear and you slip into a very “open” state, and you just let the tones take control.

To be fair, a lot of people make claims about binaural beats that border on the absurd. All sorts of snake oil like claims are made on the Internet. It’s healthy to approach it with a natural skepticism of course---but try it for yourself. If you don’t expect it to literally bring back dead ancestors or lead you directly to see the face of God, and just accept it as a brain-induced perceptual state, it can definitely alter your mood and state of mind. I've found it to be especially useful as a stress relief meditation tool.

Heinrich Wilhelm Dove first discovered binaural beats in 1839. Research into this phenomenon continued after that, but the subject of binaural beats remained something of a scientific curiosity until 134 years later, with the publishing of Gerald Oster's article "Auditory Beats in the Brain" (Scientific American, 1973). Oster's article identified and assembled the various islands of relevant research since Dove, offering fresh insight (and new laboratory findings) to research on binaural beats.

Most notably, Oster saw binaural beats as a powerful tool for cognitive and neurological research, and addressed questions such as how animals locate sounds in a three-dimensional environment. It also addresses the question of the remarkable ability of animals to pick out and focus on specific sounds in a sea of noise (what is known as the "cocktail party effect").

Oster considered binaural beats to be potentially useful as a medical diagnostic tool, not only for finding and assessing auditory impairments, but also for more general neurological conditions. Binaural beats involve different neurological pathways compared to ordinary auditory processing and can shine light on other aspects of how the brain processes sense data. For example, Oster found that a number of his subjects, people who could not perceive binaural beats, suffered from Parkinson's disease. In one case, Oster was able to follow the subject through a week-long treatment for Parkinson's disease; at the beginning of the treatment the patient couldn't perceive binaural beats, but by the end of the week of treatment, the patient was able hear them as clearly as anyone else can.

Oster also corroborated an earlier study and noted gender differences in the perception of beats. Specifically, women apparently experience two separate peaks in their ability to perceive binaural beats- peaks which may correlate with specific points in the menstrual cycle. This led Oster to wonder if binaural beats could be used as a tool for measuring relative levels of estrogen.

The perception of binaural beats is believed to originate in the superior olivary nucleus, a part of the brain stem. Binaural beats appear to be related to the brain's ability to locate the sources of sounds in three-dimensional space, and to track moving sounds. This also involves inferior colliculus (IC) neurons.

Binaural beats can influence functions of the brain in addition those related to hearing. This phenomenon is known as the frequency following response. The fundamental idea of the frequency following response is that if one receives a stimulus with a frequency in the range of brain waves, the predominant brain wave frequency is said to be likely to move towards the frequency of the stimulus (in other words, entrainment happens). Also, binaural beats have been shown to relate to both spatial perception and stereo auditory recognition Also, according to the frequency, activate of various sites in the brain.

Humans can only hear sounds within the range of 20 Hz to 20,000 Hz. Sound below 20Hz,can still have scientifically observable effects on humans. These sounds are not readily audible, especially at low volume levels. Frequencies of human brain waves are below about 40 Hz. Binaural beat frequencies account for this lack of perception Beat frequencies of 40 Hz have been produced in the brain with binaural sound and measured experimentally. They are real-world, physical phenomena.

If and when the perceived beat frequency corresponds to the delta, theta, alpha, beta, or gamma range of brainwave frequencies, the brainwaves entrain to or move towards the beat frequency.

As an example, consider what happens if a 315 Hz sine wave is played into the right ear and a 325 Hz one into the left ear: the brain is entrained towards the beat frequency (10 Hz, in the alpha range). Since alpha range is associated with relaxation, the binaural beat ultimately has a relaxing effect on the person experiencing it. If the beat frequency ends up in the beta range, it produces more alertness in the subject.

In one experiment involving binaural sound stimulation using beat frequencies in the Beta range on one group of participants and Delta/Theta range on another group of participants, the researchers found better vigilance, performance and mood in the ones receiving the Beta range stimulation. In fact, Studies have shown how, with repeated training to close frequency sounds, a plastic reorganization of the brain occurs for the trained frequencies. Evidence from different brainwave monitoring methods has demonstrated that the brains of individuals that practice mediation undergo changes. They also discovered that meditators entered certain brainwave states during their meditations.

These brainwaves can now be associated with different mental states. There are 4 generally accepted brainwave frequencies:

• Beta-14-30hz, Your normal waking state. Alertness. Concentration.

• Alpha-8-14hz, Relaxed but still alert. Daydreams, light meditative state. Some access to your unconcious mind.

• Theta-4-8hz, Present in Dreaming sleep, deep meditation, a spiritual connection, access to the subconcious mind, increased learning capabilities.

• Delta-.5-4hz, Deep,dreamless sleep

While Meditators have traditionally taken decades and up to 6 hours a day to learn and perfect the techniques of meditation, you can now attain the same effects with the technology of brainwave entrainment in a matter of minutes. This is a very powerful tool for accessing the meditative state, even more powerful when combined with ancient methods of focus and breathing.