What are binaural beats?
There are many resources out there that attempt to explain what binaural beats are, some simplified into plain English and others maintain an air of complexity by using multiple scientific terms. Binaural beats form only one facet of the multiple techniques available to induce brainwave entrainment. Binaural beats have been used recreationally, therapeutically and for many other reasons that fall in between.
In plain terms, binaural beats are responses that are invoked in one’s brain as a result from hearing auditory impulses of different frequencies in each ear. Specifically, the brainstem responses that are invoked, originate from the superior olivary nucleus of each brain hemisphere. They are heard as apparent sounds.
History Of Binaural Beats
Heinrich Wilhelm Dove discovered binaural beats in 1839. He was a noted physicist and keen experimenter. The profound, life changing implications of his discovery however were not realised until well into the 20th Century.
In 1973, Dr. Gerald Oster, MD published a landmark paper in Scientific American, “Auditory Beats In The Brain”, that launched binaural beats into the public domain. Dr. Oster considered binaural beats useful in many areas including neurological research, cognitive research and in medical diagnosis.
Thomas Campbell, a physicist and Dennis Mennerich, an engineer further enhanced research into binaural beats by conducting experiments examining its impact on consciousness. Some researchers further delved into making metaphysical claims such as telepathy and psychokinesis, and even wildly colourful claims that binaural beats can stimulate the effects of recreational drugs!
Generating Binaural Beats
In generating binaural beats, a base frequency, typically as a sinusoidal wave, is first selected. Research shows that the maximum effective base frequency threshold is somewhere between in the 1000Hz to 1500Hz range. Next, an offset frequency is selected – that is the frequency that one wishes to entrain to. For example, 7Hz is a commonly used frequency for meditation.
For illustrative purposes, let’s assume a base frequency of 300Hz, and an entrainment frequency of 7Hz. Using stereo headphones, a pure sinusoidal wave pattern of 300Hz is played in one ear, and in the other, a frequency of 307Hz is played. The brain then processes these different auditory stimuli and ‘mixes’ it in the brain, creating a binaural beat frequency of 7Hz.
The speed of entrainment is also a matter of study and debate. In most people, entrainment occurs somewhere between 6 and 7 minutes of listening to the binaural beat. Brainwave entrainment can also be facilitated by ‘ramping’, that is to start off at a higher frequency and then gently lowering it the desired range over a period of time.
Brainwave entrainment using binaural beats, although powerful, can be supplemented and augmented using other methods, such as additional auditory stimuli, visual stimuli and biofeedback. Other auditory methods that have gained momentum in brainwave entrainment recently include monaural beats, isochronic tones, sound modulation techniques, and 3D enhancement of sound using specific algorithms.