What are binaural beats?
A binaural beat is a slow pulse you hear when each ear is given a steady tone at a slightly different frequency. Play 200 Hz in the left ear and 207 Hz in the right, and you hear one tone that pulses 7 times a second. The pulse is not in the audio. It is created by your hearing, where the signals from the two ears first meet.
Hear one for yourself with the generator. It takes about ten seconds and is the quickest way to understand everything below.
How a binaural beat works
When two tones of nearly the same pitch play through one speaker, they add together in the air. The combined sound swells and fades at a rate equal to the difference between them. That is an ordinary acoustic beat, the same thing a guitarist listens for when tuning two strings.
A binaural beat is the version that happens with no mixing in the air at all. Each tone is sent to one ear only. The first place the two signals meet is in the brainstem, in the structures that compare the ears to work out where a sound is coming from. Those structures respond to the shifting timing between the two tones, and you perceive a beat.
The effect was described by the Prussian physicist Heinrich Wilhelm Dove in 1839, and brought to wide attention by Gerald Oster's 1973 article in Scientific American [1].
What you need to hear one
- Stereo headphones. Each ear must get its own tone. Speakers, or a phone set to mono audio, give you an acoustic beat instead.
- Low to middle pitches. The beat is clearest when the tones are below roughly 1,000 Hz.
- A small difference. Up to about 30 Hz the difference is heard as a beat. Beyond that, most people hear two separate tones.
The frequency bands
Binaural beats are usually described by the rate of the beat, using names borrowed from brainwave recordings.
| Name | Difference between the ears | Usually used for |
|---|---|---|
| Delta | 0.5–4 Hz | Winding down at night |
| Theta | 4–8 Hz | Rest, drifting attention |
| Alpha | 8–13 Hz | Calm, easy focus |
| Beta | 13–30 Hz | Alert work |
| Gamma | 30 Hz and up | Hard to hear as a beat at all |
The idea behind the names is entrainment: that the brain's electrical rhythms drift toward the rate of a rhythmic stimulus. For binaural beats this is not settled. A 2023 systematic review of EEG studies found that 5 of 14 supported entrainment, 8 contradicted it and 1 was mixed [2].
Binaural beats, monaural beats and isochronic tones
- Binaural beat: a different steady tone in each ear. The beat is formed by your hearing. Needs headphones. Often subtle.
- Monaural beat: two tones mixed before they reach you. The beat is in the sound itself and works on speakers.
- Isochronic tone: one tone switched on and off at a steady rate. The most obvious pulse of the three, and also audible on speakers.
What they are used for, and what is known
People listen to binaural beats to wind down, to settle before sleep, and as a backdrop for work. Research finds small to moderate average effects on attention, memory, anxiety and pain, with wide disagreement between studies and some clear failures. We keep an honest summary here: do binaural beats work?
Safety
Binaural beats are ordinary sound at ordinary levels, and studies report few problems. Keep the volume low, since long listening at high volume damages hearing regardless of what is playing. Don't listen while driving. If you have epilepsy, a history of seizures, or a neurological or heart condition, ask a clinician first.
Questions people ask
- Do binaural beats need headphones?
- Yes. The effect depends on each ear hearing a different tone. Through speakers the two tones mix in the air and you hear a normal acoustic beat, not a binaural one.
- Who discovered binaural beats?
- Heinrich Wilhelm Dove, a Prussian physicist, described them in 1839. Gerald Oster's 1973 Scientific American article, "Auditory beats in the brain", introduced them to a wide audience.
- What is the difference between binaural beats and isochronic tones?
- A binaural beat uses two steady tones, one per ear, and the pulse is formed by your hearing. An isochronic tone is a single tone switched on and off, so the pulse is in the sound itself and can be heard on speakers.
- Are binaural beats dangerous?
- They are normal sound and are generally considered low-risk at low volume. They are not recommended while driving, and people with epilepsy, seizures or neurological or heart conditions should ask a clinician first.
- Do binaural beats change your brainwaves?
- Sometimes, and not reliably. In a 2023 systematic review, 5 of 14 EEG studies supported the idea that brain activity follows the beat, 8 contradicted it and 1 was mixed.
Sources
- Oster, G. (1973). Auditory beats in the brain. Scientific American, 229(4), 94–102.
- Ingendoh, R. M., Posny, E. S., & Heine, A. (2023). Binaural beats to entrain the brain? A systematic review of the effects of binaural beat stimulation on brain oscillatory activity. PLOS ONE, 18(5), e0286023. doi.org/10.1371/journal.pone.0286023
- Basu, S., & Banerjee, B. (2023). Potential of binaural beats intervention for improving memory and attention: insights from meta-analysis and systematic review. Psychological Research, 87(3), 951–963. doi.org/10.1007/s00426-022-01706-7