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Binaural beats generator
A binaural beat is the slow pulse you hear when each ear gets a slightly different tone. This generator plays 200 Hz in your left ear and 206 Hz in your right, so you hear a 6 Hz beat; change either number while it plays.
Wear stereo headphones. Speakers mix the two tones in the room, and the beat does not form.
Labels say what people often pick each range for. They are not effects.
Ready. Put your headphones on first.
Timer off. With a timer, sound fades out over the last 30 seconds.
How the generator makes the beat
It runs two sine oscillators in your browser. The left one plays the carrier. The right one plays the carrier plus the beat frequency. Neither tone pulses on its own; your brain hears the gap between them as a slow wobble.
That is why headphones matter. Speakers let both ears hear both tones, so the beat does not reliably form.
| Band | Beat range | Preset | Often picked for |
|---|---|---|---|
| Delta | 0.5–4 Hz | 2 Hz on 150 Hz | Sleep |
| Theta | 4–8 Hz | 6 Hz on 200 Hz | Meditation |
| Alpha | 8–13 Hz | 10 Hz on 200 Hz | Unwinding |
| Beta | 13–30 Hz | 18 Hz on 250 Hz | Studying |
| Gamma | 30–40 Hz | 40 Hz on 300 Hz | Focus |
Band names come from EEG research, and their edges shift by about a hertz between sources. This page caps gamma at 40 Hz.
What the research says
The evidence is inconsistent. A 2023 systematic review of 14 EEG studies found 5 with results that fit the idea that beats pull brainwaves toward their frequency, 8 with results that contradict it, and 1 mixed. Its authors called the literature inconclusive at best
(Ingendoh et al., PLOS ONE).
A 2019 meta-analysis pooled 22 studies of memory, attention, anxiety and pain (Garcia-Argibay et al., Psychological Research). The 2023 review found the studies too different in how they made and measured the beats to compare well, so any benefit looks modest and unreliable. Treat binaural beats as a sound you may enjoy, not as a treatment for sleep problems or anxiety.
Listen safely
Keep the volume low. The US National Institute on Deafness and Other Communication Disorders says sounds at or below 70 dBA are unlikely to harm hearing even after long exposure, while long or repeated exposure at 85 dBA or more can (NIDCD). Stop if the tones give you a headache or feel unpleasant. Don't wear headphones for this while driving or cycling. This tool does not diagnose or treat any condition.
Slo is also an app
The Slo app has 70+ curated sounds for sleep, focus and relaxation, including frequency tones, on iPhone, Android and Mac.
Frequently asked questions
Do binaural beats work through speakers?
Not reliably. The beat forms only when each ear hears its own tone. Through speakers both ears hear both tones, so you get an ordinary wobble in the air instead. Use stereo headphones or earbuds.
Which frequency should I use for sleep or anxiety?
No frequency has been shown to work for either. People often choose the delta or theta ranges for sleep and meditation, which is why the presets are labelled that way. Pick a setting you find comfortable, keep the volume low, and stop if it bothers you. For ongoing anxiety or insomnia, talk to a doctor.
What does the carrier frequency change?
The pitch of the tones. The beat depends only on the gap between the two ears. A 200 Hz carrier with a 6 Hz beat plays 200 Hz on the left and 206 Hz on the right. Lower carriers sound deeper and softer; the 100–500 Hz range keeps both tones low.
Why add background noise?
Some listeners find a pure tone tiring on its own. Pink or brown noise underneath softens it. Keep the noise quiet enough that you can still hear the pulse.
Is this generator free, and does it save anything?
It is free, with no ads or signup. The tones are made in your browser, and nothing you set is sent anywhere.