Binaural Beats : The specialized Sounds
We have understood the phenomenon of Entrainment on the last page
However, we still need to answer another important question. From where we are going to produce these specialized sounds with a frequency range of less than 20 Hz and how we can make them hearable to human ears which can only listen the sounds of the frequency between 20-20,000 Hz ?
The answer to this question lies in a specialized sound known as Binaural beat.
Binaural : Relating to or having or hearing with two ears
Yes it is something to be done with two ears.
Up to now we have learnt that using specialized sounds which have a frequency between 1-20 Hz, we can entrain the existing brainwave of our mind and bring their frequency at the level of frequency of these specialized sounds. This results in our brain achieving the alpha, beta, delta or theta states of mind (depending upon the frequency of the sound) thus enabling us realize various states of deep meditation, deep sleep, hypnosis, relaxation etc.
However, the fact is we can not hear sounds with such a low frequencies.
If we can somehow manage to get the mind hear those lower frequencies, we’d be able to recreate such states of mind literally on demand.
And that’s just what one German experimenter Heinrich Wilhelm Dove discovered in 1839. He found out that by playing two coherent sounds of similar frequencies into each ear, one could produce a third “binaural beat” at a specific frequency INSIDE the mind… thereby directly influencing the brainwaves and the state of mind.
Let’s take an example. Imagine a pure tone of 400Hz is presented to the right ear, and a pure tone of 410Hz is presented to the left ear (using stereo headphones). Inside the head, the difference between the two tones is realized… and a third “binaural beat” of 10Hz is produced. This is equal to the alpha frequency, which brings about light relaxation, meditation, and creative thinking.
Binaural beats is the name given to these specialized sounds which are hearable to human ears despite having a frequency lower than 20 Hz.
Though the power of Binaural Beats was discovered in 1839 by H W Dove, the idea never took off. 134 years later, Gerald Oster published an article called “Auditory Beats in the Brain” which was published in ‘Scientific American’ in 1973. Oster’s paper was landmark not so much for any new laboratory findings, but for the way in which it identified and merge together the scattered pieces of relevant research done since Dove and thus provided this subject fresh insight and relevance to scientific research.
How Brain perceive Binaural Beats
When signals of two different frequencies (sounds) are presented, one to each ear, the brain detects phase differences between these signals. The brain processes this anomalous information differently when these phase differences are heard with stereo headphones or speakers. A perceptual integration of the two signals is perceived in the brain, producing the sensation of a third “beat”. The difference between the signals waxes and wanes as the two stereo sounds mesh in and out of phase. The binaural beat is perceived as a fluctuating rhythm at the frequency of the difference between the two auditory inputs.
The quality & frequency of the tones used to produce Binaural Beats :
To get a stimulus of 10Hz, tones of 500Hz and 510Hz may be used. Tones of 400Hz and 410Hz, or 800Hz and 810Hz will also work. The only requirements are that the tone is heard well enough and that it is below about 1000 Hz. Below 1000Hz, the wavelength of the human skull is sufficiently small so that the sound waves curve around it and the binaural beat appears to come from within.
How Binaural Beats Creates a Particular State of Consciousness
As I mentioned above, applying an external sound stimulus to the brain will eventually result in the entrainment of brainwave and bring the brain’s state closer to the stimulus frequency.
There are a growing amount of research efforts reporting changes in consciousness associated with binaural-beats. “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 delta (1 to 4 Hz) and theta (4 to 8 Hz) ranges have been associated with reports of relaxed, meditative, and creative states, and used as an aid to falling asleep.
Binaural beats in the alpha frequencies (8 to 12 Hz) have increased alpha brain waves producing calm, positive and meditative state of mind and binaural beats in the beta frequencies (typically 16 to 24 Hz) have been associated with reports of increased concentration or alertness and improved memory. Many professional hypnotist use the differing rates of Binaural beat stimulation during the induction and therapy parts of its sessions to aid in the progressive relaxation acquired when entering the Hypnotic state.
Now let us discuss some benefits of using Brainwave entrainment using Binaural Beats.