"Binaural beats may influence functions of the brain besides those related to hearing.
This phenomenon is called frequency following response."
(http://en.wikipedia.org/wiki/Binaural_beats)

Solfeggio Frequency
"These original sound frequencies were apparently used in Ancient Gregorian Chants,
such as the great hymn to St. John the Baptist, along with others
that church authorities say were lost centuries ago.
The chants and their special tones were believed to impart tremendous spiritual blessings
when sung in harmony during religious masses."

This Track begins with a binaural frequency of 30Hz (Beta waves) decreasing until 1Hz (Delta Waves).