Claim, examined
Do binaural beats work?
Play a tone of two hundred hertz in the left ear and two hundred and ten in the right, and you hear something neither ear is receiving: a slow pulse, ten times a second. That pulse is the binaural beat. Everything sold on top of it, from focus tracks to Hemi-Sync to manifestation audio, rests on the claim that the brain follows the pulse. This page is about whether it does.
Do binaural beats work?
Modestly, for relaxation and anxiety, according to the one meta-analysis that pooled the trials; and the effect varies widely between studies. There is no reliable evidence that the brain entrains to the beat frequency as the labels claim, and no evidence for the larger Hemi-Sync claims about altered states or manifestation. These studies do not establish which element of a listening session accounts for an individual response.
The phenomenon is real
Start with what is not in dispute. Present two pure tones separately to the two ears, a few hertz apart, and listeners report a beat at the difference frequency. The beat is not in the air; it is constructed in the brainstem, where the signals from the two ears first meet. The article that brought this to a wide audience described the effect carefully and suggested it might be useful as a diagnostic tool.
A widely read article laid out the binaural beat as a phenomenon of hearing: a perceived pulse at the difference between two tones delivered one to each ear, generated by the auditory system rather than by the sound itself.
Oster, “Auditory beats in the brain,” Scientific American, 1973.So the free tapes on this site do something. Put headphones on and you will hear the pulse. The question is what the pulse does next.
What Hemi-Sync claimed
In the nineteen-seventies Robert Monroe, a radio executive who had written about his own out-of-body experiences, patented a method of using binaural beats to induce particular states of consciousness and built an institute around it. The recordings were sold as Hemi-Sync, for hemispheric synchronisation: the idea that the two halves of the brain, driven by the same beat, would fall into step, and that particular beat frequencies would carry a listener into sleep, or focus, or, in the institute's Gateway programme, into states that the brochure described in terms this site would file under faith.
The claim comes in two sizes. The small one is that a beat in the alpha range relaxes you and a beat in the beta range sharpens you. The large one is the rest. The CIA Gateway document essay reads the one official assessment of the large claims that people actually cite and finds a bibliography with nothing peer-reviewed in it. This page is about the small claim, which can be tested and has been.
What the trials found
The trials are small, they vary in what they measured, and for a long time nobody pooled them. Then somebody did.
A meta-analysis pooling the controlled studies found a modest average benefit of binaural beats on measures of anxiety, and on some cognitive measures, with results that varied widely between studies and depended on how long people listened and whether they listened before or during the task.
Garcia-Argibay, Santed & Reales, “Efficacy of binaural auditory beats in cognition, anxiety, and pain perception: a meta-analysis,” Psychological Research, 2018.Read that at its true size. Modest, on average, with wide variation, in small studies. That is a finding about the studied interventions and comparison conditions. It does not show which frequency will help a particular listener, or establish an effect of this site's recordings.
Does the brain follow the beat?
The mechanism on every label is entrainment: play a ten-hertz beat and the brain's own rhythms shift toward ten hertz. That is a claim about the electroencephalogram, and it can be checked with electrodes.
A systematic review of the EEG studies found the evidence for entrainment inconsistent. Some studies reported changes in brain rhythms, others none, and the changes reported did not line up with the beat frequency in a consistent direction. The reviewers concluded that the entrainment claim is not reliably supported by the recordings.
Ingendoh, Posny & Heine, “Binaural beats to entrain the brain? A systematic review of the effects of binaural beat stimulation on brain oscillations,” PLOS ONE, 2023.This matters more than it sounds. If the brain does not reliably follow the beat, then the evidence does not justify prescribing a particular beat as a reliable way to produce a particular brain state. You may prefer one sound to another. The labels on the free tapes are names for suggested uses, not claims that everyone experiences the named state.
What your own listening can tell you
A session includes several things at once: time set aside, a sound, your expectations, and the circumstances of that day. The evidence above does not establish their relative contribution to your response. The labels calm, settle, sleep, and focus describe intended uses, not validated effects of the files on this site.
If you compare a tape with plain pink noise, keep the volume, duration, and outcome rating consistent. Such a record can help you choose what you prefer. It does not remove expectation, order effects, or changes between days, and cannot establish a treatment effect.
Safety, briefly
Binaural beats are sound at an ordinary volume and the risks are the risks of any relaxation practice. Do not listen while driving. Keep the volume low; the pulse is audible well below the level that tires the ears. If you have a seizure disorder, rhythmic stimulation of any kind is something to raise with a clinician first. And none of it treats an anxiety disorder; a tape that takes the edge off a Tuesday is not a substitute for care.
Put an idea into practice
Choose a concrete action in the free Practice Studio, or keep observations in the Experience notebook. A personal record can guide reflection; it does not by itself establish a cause.