What are binaural beats?
Last updated June 2026
Play one steady tone in your left ear and a slightly different one in your right, and your brain conjures a third sound that isn't really there — a slow pulsing "beat" at the difference between the two. That phantom beat is the heart of binaural-beat entrainment.
The definition
A binaural beat is an auditory illusion. When each ear receives a pure tone at a slightly different frequency, the brain perceives a single tone that throbs at the difference between them. Play 200 Hz in the left ear and 210 Hz in the right, and you hear a 10 Hz beat — a gentle wavering ten times a second — even though no 10 Hz sound exists in the air.
The two source tones are called the carrier frequencies; the difference between them is the beat frequency. The carrier sets the pitch you actually hear (a low hum versus a higher tone), while the beat is the rhythm that matters for entrainment. The beat frequency is what you tune to match a target brainwave band.
In short: 200 Hz (left) + 210 Hz (right) = a 10 Hz beat. Change the gap between the two tones and you change the beat — and the brainwave band you're aiming for.
The auditory and neural basis
Unlike ordinary acoustic beats — which happen in the air when two close frequencies overlap — a binaural beat is constructed inside your head. The two tones never physically mix; each travels to one ear only. The "beating" emerges where signals from both ears first meet in the auditory pathway, in the brainstem's superior olivary complex, the same circuitry your brain uses to work out which direction a sound came from.
From there comes the more speculative — and more interesting — part: the entrainment hypothesis. The idea is that when the brain registers a steady rhythmic stimulus, populations of neurons can begin to fire in time with it, nudging the brain's dominant electrical rhythm (its neural oscillations) toward the frequency of the beat. Present a 10 Hz beat and the hope is that cortical activity drifts toward the 10 Hz alpha rhythm associated with relaxed focus.
It's worth being honest here: the evidence is promising but still developing. Some studies measure shifts in EEG activity and self-reported states; others find weaker or mixed effects, and individual responses vary widely. The sensible framing is that binaural beats are a low-risk, drug-free tool many people find genuinely useful — not a guaranteed switch for your brain.
Why headphones are mandatory
This is the one non-negotiable. A binaural beat only exists because each ear receives a different tone in isolation. Play the same two tones through a speaker and they combine in the air before they ever reach you — you'd hear a fast acoustic flutter, not the smooth perceptual beat, and the entrainment basis is gone.
So binaural beats require stereo headphones or earbuds, full stop. If you want to entrain on a Bluetooth speaker, a bedside speaker, or your phone's built-in speaker, you want isochronic tones instead — a single tone pulsed on and off, which needs no stereo separation.
Which states map to which beat frequencies
The beat frequency is chosen to match the brainwave band tied to the state you're after. The five canonical EEG bands are:
- Delta (0.5–4 Hz) — deep, dreamless sleep and physical repair.
- Theta (4–8 Hz) — meditation, calm, anxiety relief, and the drifting state just before sleep.
- Alpha (8–13 Hz) — relaxed concentration and flow.
- Beta (13–30 Hz) — alert, active thinking and problem-solving.
- Gamma (30–100 Hz) — peak focus, insight, and fast learning.
As a rough guide: reach for delta or theta to wind down for sleep, alpha for calm concentration, and beta for alert, heads-down work.
How to use binaural beats in Entrain
Entrain generates the two carrier tones live on your device and splits them precisely to each ear, so the beat is exact rather than baked into a recording.
- Pick a goal. Choose Sleep, Relax, Focus, or Energy and Entrain tunes the first session to match — or dial in any frequency by hand.
- Put your headphones on. Stereo is essential; the effect won't form on a speaker.
- Set the carrier. The carrier sits in a comfortable low range — roughly 80–300 Hz, with 200 Hz a good default. Lower carriers feel softer and warmer for sleep.
- Set the beat. The beat frequency is your target band — e.g. 2 Hz for delta sleep, 6 Hz for theta calm, 10 Hz for alpha focus.
- Ease in and out. A soft fade-in keeps the start gentle, and the sleep timer (15 minutes to 8 hours) fades you out so nothing jolts you awake.
Safety note: Keep the volume comfortable and never listen while driving or operating machinery. Binaural beats are a wellness tool, not a medical device. If you have epilepsy or a seizure disorder, are pregnant, or have any medical concern, check with a healthcare professional before use.
Frequently asked
Do binaural beats really work?
The research is promising but still emerging, and responses vary from person to person. Studies have measured effects on relaxation, perceived anxiety, focus, and sleep onset for some listeners, while other results are mixed. Many people find binaural beats a useful, drug-free aid for winding down, focusing, or meditating. They are not a cure and not a substitute for medical care.
Do I need headphones for binaural beats?
Yes. A binaural beat only exists when a slightly different tone reaches each ear separately, so stereo headphones or earbuds are required. On a speaker the two tones mix in the air before they reach you and the effect is lost. If you can't use headphones, use isochronic tones instead, which work on any speaker.
What binaural beat frequency should I use for sleep versus focus?
For sleep, aim for the slow delta band (about 0.5–4 Hz). For deep relaxation and meditation, theta (4–8 Hz). For relaxed concentration and flow, alpha (8–13 Hz). For alert, active focus and problem-solving, beta (13–30 Hz). The beat frequency is the difference between the two tones, so a 10 Hz alpha beat could be 200 Hz in one ear and 210 Hz in the other.
Are binaural beats safe?
For most people binaural beats are a low-risk, drug-free relaxation tool. They are not a medical device and are not intended to diagnose, treat, or cure any condition. Keep the volume comfortable, and never listen while driving or operating machinery. If you have epilepsy or a seizure disorder, are pregnant, or have any medical concern, talk to a healthcare professional first.