Put on headphones. Play a 200 Hz tone in your left ear and a 210 Hz tone in your right. You won’t hear two notes. You’ll hear one tone that gently swells and fades ten times every second.
That pulse is a binaural beat, and the strange part is that it isn’t in the sound. Neither ear receives it. Your brain builds it when it combines what the two ears hear.
Where the beat comes from
Sound from each ear travels to the brainstem, where the two signals are compared — it’s part of how you tell which direction a sound is coming from. When the two frequencies are close but not identical, that comparison produces a slow wobble at the difference between them. 210 minus 200 gives a 10 Hz beat.
The effect was first described by the Prussian physicist Heinrich Wilhelm Dove in 1839. It reached a wide audience in 1973, when biophysicist Gerald Oster wrote about it in Scientific American and suggested it could be a useful tool for studying the brain.
A few conditions make the beat easy to hear:
- Low carrier tones. The illusion is strongest with tones below about 1,000 Hz. That’s why the presets in Binaural Tones sit between 100 and 250 Hz.
- Small differences. Beats up to roughly 30–40 Hz come through clearly. Push the gap much wider and you start hearing two separate notes instead.
- Headphones. Each ear must hear only its own tone. Speakers blend the two in the air, which creates a different, ordinary kind of beat.
Why people use them
Your brain’s electrical activity rises and falls in rhythms, usually grouped into bands: Delta for deep sleep, Theta for drowsy and meditative states, Alpha for calm alertness, Beta for active thinking and Gamma for high-level attention. The idea behind binaural beats is that listening to a steady beat in one of those ranges can gently encourage the matching state. This is often called entrainment.
So a 3.5 Hz beat (Delta) is used for sleep, 6 Hz (Theta) for meditation, 10 Hz (Alpha) for relaxed focus, 18 Hz (Beta) for energy and 40 Hz (Gamma) for alertness. Those are exactly the six presets in the app, plus Gateway, a 4 Hz beat on a low 100 Hz tone for the “mind awake, body asleep” state.
What the research says
Honestly: it’s mixed. A 2019 meta-analysis pooling 22 studies found small-to-moderate effects on anxiety, pain perception and some measures of memory and attention. A 2023 systematic review looking specifically at brainwave recordings found the evidence for true entrainment inconsistent from study to study.
What that means in practice: binaural beats aren’t medicine, and no one should promise you a guaranteed result. But many people find a consistent tone is a reliable cue — a signal to the body that it’s time to wind down, or time to work. That kind of ritual is valuable on its own, and the only way to know if it helps you is to try it for a couple of weeks.
How to get the most out of them
- Use headphones — any comfortable pair.
- Keep it quiet. You should be able to talk over it. Louder doesn’t work better.
- Give it 15–30 minutes. A few seconds tells you what it sounds like; a session tells you what it does.
- Match the tone to the moment. Sleep at bedtime, Focus for reading, Relaxation after a long day.
- Be consistent. Same tone, same time, for a week. Notice how you feel.
And a safety note: if you have epilepsy or a condition affected by sound, check with your doctor first, and never use sleep tones while driving.
Hear it for yourself: every tone mentioned here has a free five-second sample on the Try It Free page.