Binaural beats, explained without the hype

Play two tones close in pitch out loud and you hear a throb — the beating a piano tuner listens for as two strings come into tune. That throb is in the air: the two waves add and cancel before they reach you.

A binaural beat is a different thing. Each ear is given only one of the tones, so nothing combines in the air, and the pulse is heard anyway. The auditory system produces it from the two separate signals. Gerald Oster described the effect in Scientific American in 1973, and that account is still the starting point for most work on the subject.

The beat frequency is just the difference between the two tones. 200 and 206 Hz give a 6 Hz beat; so do 300 and 306 Hz. The pitch you notice is the carrier — the tones themselves. The beat is the slow sway on top of it.

Two things get chosen: the carrier and the difference. Oster reported that binaural beats are heard most clearly at carriers around 440 Hz, become less distinct as the carrier rises, and are not reported at all above roughly 900 to 1,000 Hz. The differences that produce a usable beat sit in the range of about 1 to 30 Hz. Below that the sway is slow enough to be hard to hear as a beat at all; above it the two tones start to sound like two tones.

Everything else is equipment. You need a stereo signal, both sides of the headphones working, and a volume low enough to sit with for half an hour. There is no special hardware — what headphones do and do not need to do is a short list.

EEG research groups brain activity into named bands — delta, theta, alpha, beta, gamma. These are naming conventions rather than natural boundaries, and where one band stops and the next starts differs between sources. Clinical sleep scoring, for instance, calls slow waves 0.5 to 2 Hz and stage N1 theta 4 to 7 Hz, which does not line up exactly with the ranges a consumer app uses (AASM scoring manual).

Mind Journeys uses these five, and labels each with the state it is conventionally associated with in the EEG literature — not with an outcome it promises:

• Delta · 0.5–4 Hz — Deep sleep
• Theta · 4–8 Hz — Meditation
• Alpha · 8–13 Hz — Relaxation
• Beta · 13–30 Hz — Focus
• Gamma · 30–40 Hz — Peak focus

Worth being precise about what a band label on a beat means: a 6 Hz beat is a 6 Hz beat. Calling it a “theta beat” describes the sound, not your brain. Whether brain rhythms follow the beat is the disputed part, and it is covered below.

In practice the beat is background, not the activity. People often put a low-frequency beat on while settling down to sleep, sit with a theta beat through a meditation, or run a faster beat during a block of focused work. Practitioners of lucid-dreaming and related exploration practices use long theta sessions as a listening companion to a practice they are already doing.

Two habits come up repeatedly in how people describe their own listening: keeping the volume low, so the tone sits under the thing they are doing rather than over it, and mixing the tone with rain, ocean or another ambience, because a bare sine pair is a stark sound to sit with for forty minutes. Those are reports of what people do. They are not evidence of what it achieves.

Two questions get studied, and it helps to keep them apart. First, does listening change anything measurable about mood, attention or pain? Second, do brain rhythms actually follow the beat — the mechanism usually offered as the explanation?

Outcomes

A 2019 meta-analysis of 22 studies, pooling 35 effect sizes, reported an overall medium effect of binaural-beat exposure across memory, attention, anxiety and pain (Hedges’ g = 0.45). Its largest single figure — a medium-to-large effect on self-reported anxiety for beats in the theta and delta range — rests on five effect sizes from four studies, with 159 participants in total. That is a small base for a headline number.

A later meta-analysis and systematic review looked specifically at memory and attention. It reported the existing results as encouraging but inconsistent, and called for studies with more consistent exposure times, cognitive measures and masking sounds before the effect can be judged.

A 2024 systematic review took the narrower question of everyday, non-clinical use for stress, searching six databases for randomised controlled trials. Its central finding was about the literature rather than the effect: the trials it retrieved were too heterogeneous to review meaningfully, so no pooled answer could be given.

Whether the brain follows the beat

This is where the picture is least settled. A 2023 systematic review of studies measuring brain oscillatory activity during binaural-beat stimulation found fourteen eligible studies: five reported results consistent with the entrainment hypothesis, eight reported contradictory results, and one was mixed. The authors concluded that studies attributing psychological or physiological changes to entrainment should be treated with caution.

So the honest summary is: some measured effects on how people report feeling, of modest size and in small samples; and no settled evidence that the usual explanation for them is the right one.

The individual studies are small. The anxiety figure above comes from four studies and 159 people between them; most of the field looks like that, and effect sizes from small samples move a lot when another study arrives.

The stimuli are not comparable. Carrier frequency, beat frequency, session length, whether masking noise or music is layered on top, and whether the beat plays before or during a task all vary between studies. The 2023 entrainment review makes this the centre of its critique: the outcomes are inconsistent partly because the protocols are too heterogeneous to compare with one another. Pooling them into one average hides that.

Blinding is difficult. A binaural beat is audible; participants often know whether they are in the beat condition, and many outcomes are self-reported questionnaires filled in afterwards. Expectation is a plausible contributor to results of this size, and few studies are designed to separate it out.

Outcome measures are inconsistent. The 2024 stress review abandoned a pooled synthesis precisely because the trials it found differed too much from one another to combine, which makes it hard to tell a real disagreement from two studies measuring different things.

And some things have simply not been studied. Almost all of this research looks at a single session in a laboratory. What months of nightly listening does — good, bad or nothing — is not something the literature can currently answer.

Mind Journeys is a binaural tone generator for iPhone with a curve editor: instead of a fixed track, a journey is a series of steps, and the beat frequency glides continuously from one to the next. The built-in journeys are free to play; building your own is the Pro feature.

A reasonable first listen is Mind Awake, a 30-minute meditation journey. It opens at a 10 Hz beat in alpha, glides down to 5.5 Hz over the first six minutes, holds there, then pulls back up toward 9 Hz for a couple of minutes before descending again. You will hear the tone move the whole way, with pink noise underneath. The pull-backs are deliberate: some listeners find they drift off during a long unbroken low-theta sit, and the brief rises are there to keep them present for it.

Put both earbuds in before you start. A binaural journey played on one side, or out of a speaker, is just a hum.

Do binaural beats work?

It depends what you mean by work. That you hear a beat from two separate tones is not in question — it is a well-described perceptual effect. Whether listening changes mood, attention or sleep is a different claim, and reviews of that literature disagree with each other. Meta-analyses report small-to-moderate average effects; a 2023 systematic review of the brain-activity evidence found eight of its fourteen studies contradicted the entrainment explanation.

Do I need headphones for binaural beats?

Yes, stereo headphones or earbuds. The beat only appears when each ear receives its own tone, so the two channels have to stay separate until they reach you. Over a speaker they mix in the air first, and you hear ordinary acoustic beating instead — a different sound. Any wired or wireless stereo pair works; there is nothing special to buy.

What is the difference between the carrier and the beat frequency?

The carrier is the pitch you actually hear — a steady hum, often somewhere between 100 and 300 Hz. The beat is the difference between the left and right carrier. Tones of 200 Hz and 206 Hz share a 200 Hz carrier and produce a 6 Hz beat. Changing the carrier changes the timbre; changing the difference changes the beat.

How loud and how long should I listen?

Comfortable and quiet is enough — the beat does not get stronger with volume, and loud listening over headphones carries its own risk. Sessions in published studies typically run from a few minutes to about half an hour. There is no evidence that longer is better, and no study of what daily long-term listening does either way.

Are binaural beats safe?

For most people it is simply sound played at a modest volume. Two cautions matter. Anyone with epilepsy or a seizure disorder should talk to a doctor before using brainwave audio, and nobody should listen while driving or doing anything that needs full attention. Binaural beats are not a treatment for any condition and are not a substitute for medical care.

• how binaural beats are used at bedtimeThe sleep-specific page: common practices, the small body of sleep-lab evidence, and its limits.
• why binaural beats need stereo headphonesWhy speakers cancel the effect, what to listen on, and how loud is too loud.
• how theta waves are definedThe drowsy edge between waking and sleep, and the band most meditation journeys sit in.
• what delta waves are and how they are scoredThe slowest rhythm, dominant in dreamless deep sleep and the floor a night-time journey settles onto.

Browse all guides — the binaural beat and brainwave explainers, grouped by topic.

1. Oster, G. (1973). Auditory beats in the brain. Scientific American, 229(4), 94–102. https://doi.org/10.1038/scientificamerican1073-94
2. Garcia-Argibay, M., Santed, M. A., & Reales, J. M. (2019). Efficacy of binaural auditory beats in cognition, anxiety, and pain perception: a meta-analysis. Psychological Research, 83(2), 357–372. https://doi.org/10.1007/s00426-018-1066-8
3. 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(4), 951–963. https://doi.org/10.1007/s00426-022-01706-7
4. Platt, J., & Hammond, L. (2024). Is non-clinical, personal use of binaural beats audio an effective stress-management strategy? A systematic review of randomised control trials. Advances in Mental Health, 23(2), 258–286. https://doi.org/10.1080/18387357.2024.2374759
5. 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, and the implications for psychological research and intervention. PLOS ONE, 18(5), e0286023. https://doi.org/10.1371/journal.pone.0286023
6. Berry, R. B., et al. The AASM Manual for the Scoring of Sleep and Associated Events: Rules, Terminology and Technical Specifications. American Academy of Sleep Medicine. https://aasm.org/clinical-resources/scoring-manual/