Binaural beats result when two different frequencies in each ear produce a third frequency detected by your brain known as binaural beats.

Binaural beats are two different frequency beats that are listened to in each ear. In one ear is one that is faster while a slower one is in the other ear. The interesting thing that occurs is that the brain only "hears" the difference of these two sound(s/ waves). Your brain detects the phase variation between the frequencies and tries to reconcile that difference resulting in the binaural beat. Essentially the two sounds partially phase each other out only leaving a wave behind that is the difference of the two.

For example, if a frequency of 50 Hz is presented to your left ear, and a frequency of 55 Hz is presented to your right ear, your brain “hears” a third frequency pulsing at 5 Hz, the exact difference between the two frequencies.

This has resulted in researchers discovering when this happens the brain resonates in tune of this resulting beat. With a 10 Hz binaural beat created this was you can trigger the brain to resonate in with the Alpha frequency automatically inducing the brain into the Alpha range.

These binarual beats may be used to help guide the brain into states of focus or relaxation that may otherwise have trouble achieving or to reach deeper depths of these states of the brain.

Please feel free to check out the video below and other resources I have included below to learn more.

A binaural beat is an auditory illusion perceived when two different pure-tone sine waves, both with frequencies lower than 1500 Hz, with less than a 40 Hz difference between them, are presented to a listener dichotically (one through each ear). For example, if a 530 Hz pure tone is presented to a subject's right ear, while a 520 Hz pure tone is presented to the subject's left ear, the listener will perceive the auditory illusion of a third tone, in addition to the two pure-tones presented to each ear. The third sound is called a binaural beat, and in this example would have a perceived pitch correlating to a frequency of 10 Hz, that being the difference between the 530 Hz and 520 Hz pure tones presented to each ear. ~ Source wikipedia