7.83 Hz

Instructions:

“Schumann’s Resonance” is a term used for a specific sound frequency oscillating around 7.83 Hz. In the Earth’s atmosphere – in a so called “cavity” between the surface of the Earth and its ionosphere – there are stationary electromagnetic waves.

If a human brain is exposed to two mutually similar sound frequencies via stereophonic headphones or well-positioned loudspeakers, the brain tunes into the third frequency which represents the difference between the two frequencies. For instance, if one ear is exposed to frequency of 100 Hz and the other ear is exposed to 104 Hz frequency, the brain tunes in the frequency representing the difference between those two, to 4 Hz. This phenomenon is called frequency following response. This frequency, in reality non-existent, (as the brain has created it itself) can be measured via EEG as the electric activity of the neo-cortex. Important fact is that the brain tunes into the given difference of frequencies as a whole, with both hemispheres, whereas normally there is a difference between the electric activities of the individual hemispheres.