How binaural beats actually work
A binaural beat is not a third physical tone mixed in the air. It is a perception your auditory system creates when the left ear and right ear each receive a steady pure tone at a slightly different frequency — through stereo headphones.
If the left ear hears 200 Hz and the right ear hears 210 Hz, the difference is 10 Hz. Many listeners perceive a soft pulsing or “beating” at that difference. The brain, especially brainstem centers that compare the two ears, is where the effect is generated.
Why headphones are required: speakers or mono playback mix the tones before they reach you. Then there is no clean left/right difference for the brain to compare.
Three terms that end most confusion
- Carrier — the base pitch in one ear (e.g. 200 Hz). Comfort and audibility live here.
- Beat frequency — the difference between ears (e.g. 10 Hz). This is the “pulse rate” people map to band names.
- Band label (delta/theta/alpha/…) — a design target borrowed from EEG charts, not a guarantee your lab EEG will match.
Interactive demos: What are binaural beats? · Carrier frequency · Beat frequency · Beat calculator.
On Binaural Beat Machine: the free Console and Programs use true stereo design. Pick a state, press ENGAGE, and listen on headphones.
- Headphones guide
- Alpha · Beta · Theta · Delta · Gamma · Interactive band map
- Open the free Console · Programs · Purpose pages
Headphones required for true binaural. Site UI is English — click ENGAGE / Programs to listen.