What are binaural beats? When you hear two tones, one in each ear, that are slightly different in frequency, your brain processes a beat at the difference of the frequencies. This is called a binaural beat. Here is an example: Imagine listening to the sound in your left ear with a frequency of 132 Hertz (Hz). In your right ear, listen to the normal frequency of 121 Hz. However, your brain gradually collapses in response to the difference – or 11 Hz. Instead of hearing two different tones, instead hear a tone at 11 Hz (more than two tones assigned to each ear).