Binaural Beats

Binaural beats are a form of  brainwave entrainment using two separate sounds that combine to form one sound inside your brain. 

One benefit is that in order for the brain to create a binaural beat, it must use both hemispheres of the brain (right and left), which can result in what is called hemispheric synchronization or hemi-sync.  

Because they deliver a different sound to each side binaural beat audios must be listened to with headphones.