Binaural beats: what they are and what they aren’t

Play a 200 Hz tone in your left ear and a 206 Hz tone in your right, and you’ll hear something neither ear is playing: a slow pulse, six times a second. That pulse is a binaural beat. It’s a real effect, first described by the physicist Heinrich Wilhelm Dove in 1839. A lot of what’s said about it online is less real. Here’s what holds up.

What you’re hearing

Each ear gets one steady pitch. Your brain compares the two signals, and the small difference between them is heard as a gentle rise and fall in loudness: a beat at the difference frequency. 206 minus 200 gives a 6 Hz beat.

This is why binaural beats need headphones. Each ear has to hear only its own tone. Through a speaker, both tones reach both ears and combine in the air, so you hear an ordinary acoustic beat instead: a related sound, but not a binaural one.

The beat is clearest with fairly low tones and a small difference between the ears. As the difference grows, the pulse speeds up and starts to sound like roughness, and eventually like two separate notes.

Where the names come from

Delta, theta, alpha, beta and gamma are names for ranges of the brain’s electrical rhythms, as measured by EEG:

Band	Range	Usually seen during
Delta	below 4 Hz	deep sleep
Theta	4 to 8 Hz	drowsiness, light sleep
Alpha	8 to 12 Hz	relaxed wakefulness, eyes closed
Beta	13 to 30 Hz	alert, busy thinking
Gamma	above 30 Hz	focused processing

Binaural beat presets borrow these names because of an idea called entrainment: that a beat at a band’s frequency nudges the brain toward that rhythm. Uyu’s presets (2 Hz Delta, 6 Hz Theta, 10 Hz Alpha, 16 Hz Beta and 40 Hz Gamma) are named for the band their beat falls in, and that’s all the name claims.

What the research shows

On entrainment, the evidence is split. A 2023 systematic review looked at 14 studies that measured brain activity while people listened to binaural beats. Five found results in line with entrainment, eight found results that contradicted it, and one was mixed. The authors called the evidence inconclusive and pointed out how differently the studies were run.

Studies of mood, attention and anxiety also point in different directions, and where effects appear they’re usually measured over short sessions in a lab. There’s no good evidence that a binaural beat treats insomnia or any other condition.

What is well established is the sound itself: a soft, steady pulse that many people find easy to rest or focus with. If that’s what you want from it, it does that. If you’re hoping it will rewire your sleep, the research doesn’t back that up.

What they aren’t

• Not a treatment. Tones are for relaxation and focus. Uyu is not a medical device.
• Not “digital drugs”. Stories about beats that make you high are just stories.
• Not magic numbers. The same goes for pure tones like 432 Hz, 528 Hz and the solfeggio set. These numbers come with stories attached, but there’s no good evidence that any particular frequency heals anything. They’re steady, pleasant tones, and that’s how Uyu offers them.

Listening safely

• Keep the volume low. A tone works best sitting under other sounds, not on top of them.
• If you might fall asleep with headphones on, set a timer so the sound stops.
• If you have epilepsy, a seizure condition or a hearing condition, ask a doctor first.

Trying them in Uyu

Open Tones, pick a beat, and put it under rain or brown noise at a low level, with headphones on. Pure tones like 432 Hz don’t need headphones and sound fine through a speaker. If you want to experiment, the sound sheet lets you set each ear’s pitch yourself, and the beat is shown as you go.

Sources

• Oster G. Auditory beats in the brain. Scientific American. 1973;229(4):94–102.
• Ingendoh RM, Posny ES, Heine A. Binaural beats to entrain the brain? A systematic review of the effects of binaural beat stimulation on brain oscillatory activity, and the implications for psychological research and intervention. PLOS ONE. 2023;18(5):e0286023.