Binaural beats generator
Two tones, one per ear, a few hertz apart. Your brain hears the difference as a slow pulse. Headphones required.
Volume first. Turn your device volume down before pressing play, then raise it slowly. Tones start quiet on purpose. Keep headphones off your ears until you know how loud it is.
How binaural beats work
Sound from each ear travels to the brainstem, where neurons in the superior olivary complex compare the timing of the two signals; this is normally how we locate sounds. When the two ears get steady tones a few hertz apart, the timing difference keeps rolling round, and we perceive it as a gentle wobble in loudness at the difference frequency. First described by Heinrich Wilhelm Dove in 1839, it is a genuine and easily demonstrated auditory effect.
What the evidence says
The band names (delta, theta, alpha, beta, gamma) come from EEG brain-wave research. The idea that a beat at, say, 10 Hz nudges the brain towards alpha activity ("entrainment") is popular but not firmly established. Reviews of the research find mixed results. If you enjoy the sound for relaxation or as a focus ritual, there is no harm at low volume, but do not rely on it for medical conditions such as insomnia or anxiety, and avoid it while driving.
Questions people ask
What are binaural beats?
When each ear hears a slightly different frequency, for example 200 Hz in the left and 210 Hz in the right, the brain perceives a third, pulsing "beat" at the difference, 10 Hz. The beat is created in the auditory system, not in the air, which is why it only works with headphones.
Do binaural beats really improve focus, sleep or relaxation?
The evidence is mixed. Some small studies report effects on mood or anxiety, while systematic reviews describe the results as inconsistent and the studies as varied in quality. Treat them as an interesting auditory phenomenon and personal experiment, not a treatment.
Why do I need headphones?
Each ear must receive only its own tone. Through speakers both tones reach both ears and mix in the air, producing an ordinary acoustic beat instead of a binaural one.
What carrier frequency should I use?
Binaural beats are heard most clearly with carrier tones below about 1000 Hz, with 200–500 Hz a common range. The effect weakens as the difference grows beyond about 30 Hz, where you start to hear two separate tones instead.
Keep testing
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