To measure brainwaves, a technology named EEG (Electroencephalography) is used. A set of electrodes are placed on certain locations on the surface of the scalp. The brain's electrical vibrations will be picked up, resulting in data that displays in frequencies in Hz. This data will be able to tell your current state of awareness. You can measure the total amplitude of frequencies in for the whole brain, or one can choose to measure only a selected area of the brain, however that is mostly just done if there is some kind of problem that is believed to come from a certain part of the brain, or a couple of areas not working together as they should. But we don't need to  go into that here.

The frequencies are normally named and categorized into four states. In recent years five because of the attention given to the possible benefit of Gamma waves.

State:	Frequency range:	State of mind
Gamma	28Hz +	Very high stress, high tension and anxiety. Interestingly enough though, it has been found amongst Buddhist monks in very deep states of meditation that they show high rates of Gamma at the same time as Theta and Delta.
Beta	13 - 28Hz	Normal awake state. Doing active things, concentration and stress.
Alpha	7 - 13Hz	Light to semi-deep relaxation, positive and creative state. Feels very nice.
Theta	4 - 7Hz	The state you are in when you are falling asleep. Very deep relaxation and meditative experiences. If you are fully aware in this state you usually feel tremendous well-being.
Delta	0.5 - 4Hz	Deep sleep. Deeply rejuvenating.

The importance of SMR

Some people also mention a state they call SMR (Sensory motor rhythm) which ranges from 12-15Hz. So in fact this ranges from high Alpha to mid-Beta. This is a very interesting state and it has been found that people with ADD/ADHD has a lack of this frequency range. SMR is a relaxed, yet focused state. When you feel extremely focused and yet relaxed while working with something, you are very effective and this is probably the state you experience in those cases. Some times it may feel like you forget about everything else but what you are doing at the moment. If you have a good SMR ratio in your brain you will find meditation easier since you will have an easier time remaining awake and still relaxed.

You might now begin to understand that it is not only one frequency present at a time. The whole spectrum is always used, but depending on your state the amplification of the different frequencies vary. For instance, you might feel very tired but unable to sleep: In that case you probably have Delta/low Theta waves but too much Beta. This unbalance may make you feel uneasy and restless. In this case, stimulating lower frequencies by the use of brainwave entrainment might help.

 

Binaural beats

The different states (frequencies) described above can be created in the brain by the use of a pretty simple sound technology. Let us say you want to relax in to a Alpha state and decide to stimulate the 10Hz frequency (Alpha: 7-13Hz). Do not confuse the Hz used to describe the pitch of a note with brainwave frequencies. A 10hz frequency in brainwave entrainment means a tone that has 10 pulses per second. A 10Hz note however, you can not even hear since the human ear only picks up from about 20Hz-20Khz (20.000Hz).

What you do is to play one steady tone in the left ear at lets say 400Hz, and in the left ear a 410Hz tone. What will happen now is that these two tones creates a pulsing tone and it will sound like it comes from the middle of your head, just between your ears. The pulse will be 10Hz because this is the difference between the tones. (410Hz - 400Hz = 10Hz). This pulse is not physically there. It is being created by the brain and it will begin to stimulate this frequency in your brain. Soon you will begin feeling more relaxed and if someone did a EEG test on you after 10 minutes you would see that you have more amplitude in Alpha frequencies around 10Hz.

 

Brainwave synchronization

What will also happen is that your left and right brain hemisphere - you left and right half of the brain - will begin to synchronize. Most people use mostly the left side of the brain. This side is used mostly in logical tasks. The right brain is the artistic, creative side and musicians and people with creative jobs use this side of the brain more. When you are in a creative state you often feel very good. The optimal state though is to use both hemispheres together.

You brain will begin to release and produce more endorphin and other "feel good chemicals" that occurs naturally, but which are under-produced due to stress and anxiety. Binaural helps and let's the brain relax and do what it is supposed to do, making you feel fantastic.

People using mostly the left half of the brain may find that they can logically understand things, but not express themselves creatively or emotionally, while people using mostly the right side are very good at describing things with feelings and colors etc but unable to logically explain things and tend to day dream more. Using both sides together brings you a fantastic advantage in your life and if you practice regularly with binaural beats you will begin to use more and more of the brain. Einstein was extremely smart but still "only" used about 17% of his brain! Most people doesn't even use half of that.

 

A whole new dimension to life

By the use of brainwave entrainment you will achieve the same results as normal meditation but much faster. You will begin using more and more of your brain and find that you feel happier, think more clearly, are much more relaxed and stress free at the same time as you are able to stay concentrated for much longer.

But this is only the beginning. If you continue you will find that you start being more and more aware in dreams, in near-sleep states and start to have a flow to your life. After even more time you may find that you are awake while the body is asleep and this allows you to temporarily leave your physical body. (Out of body experience, OOBE).

After some practice you might find that you hear sounds in your head. This can be many types of sounds. Drum sounds, tones, music or surf/wind-like sounds. This means you are beginning to hear the inner sounds talked about in some yoga traditions. Just let them be. They seem to have tremendously good effects. But again, this is only the start. Start already today and you will not regret it.