Binaural Sound Central allows you to meditate and relax with true Binaural Beats. These beats are made by putting 2 distinct separate sine waves or pitches in each year. The interference of the two frequencies is what your brain makes into a binaural beat. To use this app and get the full effect you have to use earbuds/headphones to get the discrete sounds to each ear.

Gamma - Higher brain activity, Problem Solving

Beta - Active, Busy Thinking, Active Concentration

Alpha - Relaxation

Theta - Dreams, Deep Meditation, REM Sleep

Delta - Deep dreamless sleep