By using x hz in one ear and x*2 hz in the other ear it, sort of, forces the body to lock into the phased frequency.
This ELF frequency is said to affect consciousness in a very positive way. It is within the Delta range (dreamless sleep). Now, this is said (according to Ronald DeStruelle (Holistic institute)) to promote entrainment between the hypothalamus, pituitary and pineal centers of the brain.
It is said to synchronize the functioning of the brain-stem areas also known as the extended reticular (net-like) -thalamic activation system, implicated in a variety of functions associated with consciousness.
The reticular system interprets and reacts on information from internal stimuli, emotions and beliefs as well as external sensory stimuli by regulating arousal states, focus and states of awareness.