Binaural beats generator
Put on headphones. Your left ear hears one pure tone, your right ear a slightly different one, and your brain hears a slow pulse at the difference.
Play a 200 Hz tone in one ear and 206 Hz in the other and you will perceive a gentle 6 Hz wobble, even though neither ear receives it. The beat is assembled in the superior olivary complex of the brainstem, the same circuitry that locates sounds by comparing timing between your ears. Heinrich Wilhelm Dove described the effect in 1839.
Tick "mix both tones" to hear the difference: with both tones in both ears the pulse is a physical swell in loudness, and the waveform shows exactly why.
Beat frequencies and what people use them for
| Band | Beat | Brain state it is named after | Typical use |
|---|---|---|---|
| Delta | 1–4 Hz | Deep, dreamless sleep | Falling asleep |
| Theta | 4–8 Hz | Drowsiness, meditation | Deep relaxation |
| Alpha | 8–13 Hz | Relaxed wakefulness | Calm focus, reading |
| Beta | 13–30 Hz | Active thinking | Alertness, study |
| Gamma | 30–40+ Hz | Intense concentration | Focus sessions |
The names come from EEG bands. The idea that a matching beat "entrains" the brain into that state is popular but has mixed support, so judge by how you feel rather than by the label.
Binaural beats vs noise
Binaural beats are a tone with a pulse; noise is a wideband hush. They do different jobs, and they combine well: a quiet pink or brown noise bed hides the thin sine tones and makes long sessions more comfortable. For pure masking of distractions, brown noise or pink noise alone does more.
Questions
Do binaural beats work?
The beat itself is real: your brainstem genuinely perceives a pulse at the difference frequency. Whether that changes mood, focus or sleep is less clear. Reviews, such as Garcia-Argibay et al. (2019, Psychological Research), found small effects on anxiety, memory and attention but inconsistent results across studies.
Do I need headphones for binaural beats?
Yes. Each ear must receive only its own tone. Through speakers both tones mix in the air and you hear an ordinary acoustic beat instead.
What frequency is best for sleep, focus or relaxation?
Common conventions: delta (1–4 Hz) for sleep, theta (4–8 Hz) for deep relaxation, alpha (8–13 Hz) for calm focus, beta (13–30 Hz) for alertness and gamma (around 40 Hz) for concentration. These are traditions, not proven prescriptions.
Are binaural beats safe?
For most people, at modest volume, yes. People with epilepsy or a seizure history should ask a doctor first. Do not use them while driving.
Why is the carrier tone limited to 500 Hz?
Binaural beats are heard most strongly with carriers below about 1,000 Hz, and are weak above 1,500 Hz because of how the brain compares timing between the ears.