Hearing and binaural beats

The human ear has very strange abilities. An example of this are so-called binaural beats. The unusual thing is that there are actually no real beats happening at all!

The left and the right ear are listening to sounds of slightly different frequencies. From the difference of the frequencies (in Hz) then results the frequency of the beats. For example, if the left ear is exposed to a 440 Hz tone and the right ear to 439 Hz, then this difference results in one binaural beat per second (1 Hz). At 438 Hz for the right ear, the frequency doubles to 2 Hz.

The effect works similarly when the sounds are output through speakers. However, physical overlays and interferences – (ie beats) – are actually happening here. The crazy thing about binaural beats from headphones is that there is not really that superposition of sounds. Each ear hears a continuous sound at a constant frequency.

The beats seem to arise only during processing in the brain.

This is basic prototype of a Javascript Audio Synthesizer. I’m considering to extend this early version with further features, maybe it becomes a “full-fledged” synthesizer one day.

Currently its features are Low-Pass and High-Pass Filter and as well as a delay effect with certain settings.

Update: there is also a newer version with a different effect which offers nicer sound (probably due to my improper usage of audiolet)