This article will give the reader a brief introuction to binaural beats, explaining what they are and how they work to create various brain states.
Binaural beats are produced in the brain as the result of a combination of two separate tones – one played in each ear. As these tones are combined, the brain detects the phase differences between the two, creating a a third, pulsing ‘ghost’ beat’. This beat, depending on the rate of the rhythmic flucuations as the tones shift in-and-out of phase can be used to induce varying states of consciousness including focus & concentration, deep sleep, relaxation and deep meditation.
It was the German experimenter H.W. Dove who initially discovered this auditory phenomenon way back in 1839, and his discovery paved the way for the modern era in which anyone can use brainwave entrainment to create brain states on demand.
These mind states are created through an interesting process called the ‘frequency following response’. The FFR can be defined as the calibration of your brain waves so that they are in more-or-less in alignment with the binaural ‘ghost’ beat. In simpler terms, your brain waves will match the beat-frequency (the difference between the tones), producing the desired state of consciousness.
An example – let’s say a 310Hz sine wave is played through the right ear, and a seperate tone of 300Hz is presented to the left, your brain will interpret the mathematical difference between the two tones, which is, you guessed it – 10Hz! 310hz – 300hz = 10hz. Note that this beat is actually illusory and created by your brain as it sums the difference – therefore headphones are required to properly perceive the binaural beat. Technically speaking, headphones are not mandatory – you could perceive the ghost beat as you sit between a set of high quality monitors, but headphones definitely provide the most direct and immersive experience. Going back to our example, a 10hz alpha binaural beat will result in a relaxed, pensive state of awareness for most people.
Many researchers have documented changes in consciousness associated with binaural beats. According to Owens & Atwater (1995);
“The subjective effect of listening to binaural beats may be relaxing or stimulating, depending on the frequency of the binaural-beat stimulation”.
Binaural beats in the theta range have been shown to encourage restful sleep, and relaxed, creative states of awareness (Hiew, 1995).
The efficacy of binaural beats in their influence on brainwaves has also been demonstrated by Foster (1990), who found that beat-frequencies between 8 & 12 Hz had a noticeable effect in increasing the production alpha brain wave activity.
Binaural beats in the beta range are associated associated with an increase in focus, (Monroe, 1985) and an improvement in memory (Kennerly, 1994). Theta also plays a part in memory consolidation – in one study, a high amount of theta waves were present in subjects immediately before being prompted to remember a piece of information (Ranganath, 2011).
FREQUENCY BANDS & ASSOCIATIONS
The table below will give you a better idea of the effects associated with each frequency band;
The following graphic shows how these different brainwaves look in visual form, after transmission through EEG (electroencephalogram) sensors. The brainwave patterns range from low-frequency, high amptude waves at Delta to high-frequency, low amplitude waves at Gamma.
