The Schumann resonances (SR) are a set of spectrum peaks in the extremely low frequency (ELF) portion of the Earth‘s electromagnetic field spectrum. Schumann resonances are global electromagnetic resonances, excited by lightning discharges in the cavity formed by the Earth’s surface and the ionosphere.
(from Wikipedia http://en.wikipedia.org/wiki/Schumann_resonances)
Schumann resonances are claimed to provide equilibrium between people and Earth, since the main frequency (7.83Hz) has a wavelength of 38000Km (about the circumference of the Earth). Most of scientific community argued that a body small like the human one can’t obtain advantages from this frequency. Despite of this, some audiophiles (in which I also agree) says that when in presence of a Schumann resonance the music listening is more relaxed.