Music & tuning · two carriers, one per ear
Binaural Beat Generator
Two sine waves are generated at once and hard-panned - one strictly to the left ear, one to the right. The difference between them is the beat frequency, from a slow delta throb to a fast gamma shimmer. Set a carrier and a beat; the two ear frequencies are derived and shown exactly.
Use headphones. Each ear must receive a different frequency for the beat to be binaural; through stereo speakers you only get an ordinary loudness beat. Keep the level low - a steady two-tone signal is easy to listen to for longer than is wise.
Delta 0.5–4 · Theta 4–8 · Alpha 8–13 · Beta 13–30 · Gamma 30–50 Hz.
Ready. Press play with headphones on.
Left ear
195 Hz
Right ear
205 Hz
Beat
10 Hz
Band
Alpha
Carrier
200 Hz
Derivation
L − beat/2 · R + beat/2
Speaker playback sums both carriers into each ear, so what you hear is an amplitude beat - the loudness rising and falling - not a binaural beat. Only separated channels produce the neural difference tone the technique relies on.
A binaural beat is an auditory illusion. When each ear hears a pure tone and the two tones differ by a few hertz, the brainstem's superior olivary complex responds to the difference between them, and you perceive a slow rhythm at that difference frequency even though no sound is physically present at it. The two ear frequencies here are derived so the difference is exactly the beat:
left = carrier − beat/2 · right = carrier + beat/2
The bands below are the conventional human EEG rhythms. Selecting one sets the beat to a representative rate. The names describe the frequency, not a guaranteed effect.
| Band | Beat rate | Associated state (EEG literature) |
|---|---|---|
| Delta | 0.5 – 4 Hz | Deep sleep, 0.5–4 Hz |
| Theta | 4 – 8 Hz | Drowsiness, meditation, 4–8 Hz |
| Alpha | 8 – 13 Hz | Relaxed wakefulness, 8–13 Hz |
| Beta | 13 – 30 Hz | Alert focus, 13–30 Hz |
| Gamma | 30 – 50 Hz | High-level processing, 30–50 Hz |
Keep the carrier above roughly 100 Hz and the beat modest (1–20 Hz) for comfortable listening. Very high carriers become piercing; very fast beats blur into a roughness rather than a distinct pulse.
Do I need headphones?
Yes. A binaural beat exists only when each ear receives its own steady frequency. With headphones, the left ear hears one carrier and the right ear another, and the brainstem derives the difference. Over loudspeakers both ears hear both tones mixed, which produces an ordinary amplitude beat - a slow pulsing of loudness in the room - rather than a binaural one. The two are not the same phenomenon.
What does the carrier frequency change?
The carrier sets the pitch you actually hear; the beat sets the difference between the ears. Most listeners find carriers between about 100 Hz and 500 Hz the most comfortable for beats, because low carriers make the beat easy to follow while high carriers (>1 kHz) can be piercing. The default 200 Hz is a reasonable middle ground.
Do binaural beats change brainwaves or improve focus or sleep?
The evidence is not well established. Small studies have reported changes in EEG at the beat frequency and modest effects on anxiety, attention or sleep, but results are inconsistent, samples are small and several attempts to reproduce the effects have failed. Treat binaural beats as a pleasant background tone, not a treatment. Anyone with epilepsy or a seizure history should be careful with rhythmic stimuli and consult a clinician.
What do the delta, theta, alpha, beta and gamma labels mean?
They are the conventional EEG bands, named by frequency: delta 0.5–4 Hz, theta 4–8 Hz, alpha 8–13 Hz, beta 13–30 Hz, gamma 30–50 Hz. The buttons set the beat to a representative frequency in each band. The label describes the beat rate, not a guaranteed effect on your brain - it is a naming convention borrowed from the EEG literature.
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