Sound & programs · 12 MIN READ · 7 SOURCE QUOTES
Binaural beats
A binaural beat is an effect built inside the head. Play a 100-hertz tone in one ear and a 104-hertz tone in the other through headphones, and the listener perceives a slow pulse at the four-hertz difference, although neither ear receives that pulse. The German experimenter H. W. Dove described the effect in 1839, and the Institute's papers cite Gerald Oster's 1973 Scientific American article on the effect. The Institute's journal places its origin in the brain stem, in the superior olivary nuclei where signals from the two ears first meet.
Monroe did not invent binaural beats and said so. His lab had spent years feeding the brain slow rhythms as changes in sound loudness, which he said could put a listener to sleep or keep one awake. Binaural beats delivered the rhythm itself, which he judged about 50 percent more efficient. The idea is that brain waves tend to follow a rhythmic stimulus, the frequency-following response, and that slow rhythms such as theta and delta go with drowsy and sleeping states. Physicist Tom Campbell, who helped build the first tapes, says the target was four hertz because that was the rate Monroe reported during his vibrations.
What the beat can do is still argued. Institute researchers have recorded a faint EEG response and, in small studies, shifts in brain-wave activity, and a 1998 Duke-led study found beta beats improved vigilance more than slow beats did. Campbell recommends binaural beats to beginners but says there is no magic in them: they put people in the state an experienced meditator reaches, they do not force an out-of-body experience, and they can become training wheels. The Institute adds that a plain beat bores the brain, which is one reason Hemi-Sync recordings keep changing.
A binaural beat is a slow pulse the brain builds from two slightly different tones, one in each ear; Monroe made it the engine of Hemi-Sync.
Key points
What a binaural beat is
Two pure tones close in pitch, one in each ear, produce a perceived pulse at the difference between them. The Institute's journal says the effect arises when the tones sit below about 1,000 hertz and differ by roughly 1 to 30 hertz, the range of brain-wave rhythms. The pulse is not in the air and neither ear hears it. Play the same two tones through speakers and they mix in the room, giving an audible throbbing that is a different thing from a binaural beat.
Dove, Oster and Monroe
The Institute's own papers credit Dove with discovering the effect in 1839 and cite Oster's 1973 article. Campbell recalls that a colleague at Monroe's lab found Oster's article, that the two of them borrowed equipment from their university labs to make tapes, and that Monroe liked the results enough to see a business in them. Monroe's own contribution, as he described it, was applying his lab's frequency-following work to the effect and building programs around it.
Why the brain is said to follow
The Institute's explanation rests on the frequency-following response: the tendency of brain-wave rhythms to echo a rhythmic stimulus. Atwater measured it as an extremely faint signal, visible only after averaging many exposures, and a 2009 Institute paper proposes that the beat starts in the brain stem and reaches the reticular formation, which helps set cortical arousal. Monroe added that because each ear's signal crosses to the opposite hemisphere, making the beat requires both hemispheres to act in unison.
Brain-wave bands and the states they go with
EEG researchers group rhythms into delta (below about 4 hertz, deep sleep), theta (about 4 to 8, drowsy and hypnagogic states), alpha (about 8 to 12, relaxed wakefulness) and beta (above that, alert thinking). Monroe called theta the crossover between ordinary waking and delta sleep, where creativity and much meditation happen, and said alpha, mere conscious relaxation, did not interest him enough to play with. Beat frequencies in a recording are chosen to point toward one of these bands.
How the lab used the beat
Campbell says he and a colleague tried different waveforms, bass tones and beat rates, settled near four hertz and tested the tapes on families and friends. The effect was obvious on almost everyone, though not the same for everyone: some people lost consciousness at once, a reaction later called clicking out, some found the sound annoying, and most drifted in a pleasant, barely conscious state with pictures and impressions. Monroe then tried the tapes on many more people.
A single beat versus Hemi-Sync recordings
Atwater's own tests used a complex 45-minute sequence, and he says Institute tapes change their beat patterns as the listener moves through relaxation, the energy conversion box and other tasks, using shifts borrowed from music theory. Nancy Walter says a steady binaural beat, which is just the difference between two tones, becomes boring to the brain after a while, while recordings that keep changing hold attention. That is the Institute's case for treating Hemi-Sync as more than a beat.
What the studies found
A 1998 study at Duke with 29 volunteers found that beta-range beats, 16 and 24 hertz, improved target detection and mood compared with theta and delta beats, though no EEG was recorded. A graduate thesis with 50 college students and a double-blind design found better word recall and digit-task scores with beta beats under music than with the music alone. A six-person study reported rising theta activity in five of the six. Authors in the Institute's journal repeatedly call the evidence preliminary.
Beginner tool, then training wheels
Campbell says binaural beats help beginners who lack the skill to reach theta, but warns that depending on them keeps you from learning to enter the state yourself, like a rider who never takes the training wheels off. The Institute's design follows that logic: Gateway exercises use the sound to teach a state you can later recall by memory and intention. Monroe said that once a person learns a state with Hemi-Sync, they remember it and can return to it at will.
In their own words
Quotes are checked word for word against the recordings and documents they come from. Bracketed words correct transcription errors; “…” marks an omission.
“These brainwave frequencies that are common in the human brain are of a frequency that is lower than human hearing. Let's use an illustration that here's an 8 hertz signal, which means 8 cycles per second, that we cannot hear. So how to get it into the human brain, other than using an amplitude method? We found then the, the binaural beat would work very beautifully in that respect.”
“Now, if we take input one of those signals in one [ear], and the other in the other ear, then that wavering is not heard in either [ear], but the human brain synthesizes that signal. Therefore, in order to do this, both the left and right hemispheres of the brain must synchronize, they must act in unison, to produce that third signal to hear it, as it were, although … the human brain never really hears it, but it does create the electrical signal.”
“When tones of two different frequencies are presented separately to each ear, the superior olivary nuclei within the medulla of the brain stem synthesize the two sounds into a single low-frequency tone, the binaural beat. The binaural beat pulses with the overall frequency of the difference between the two original tones. This electrical activity is then conducted to the cortex where it may be recorded by EEG electrodes.”
“Bob had this experience of four hertz vibration just as he went out of body. And he reported that. So we started working for four hertz. That was our target just because Bob experienced that. And we found four hertz actually was something like 3.878 or something like that, but really close to four hertz that was optimal for creating this state in which your mind was open to other things.”
“You have to measure lots of exposures. … You gotta measure a lot of them. And then you go back and you stack them all up? And you find, yes, in fact, the brain does have this little response to the binaural beat.”
“Presentation of beta-frequency binaural beats yielded more correct target detections and fewer false alarms than presentation of theta/delta frequency binaural beats. In addition, the beta-frequency beats were associated with less negative mood. Results suggest that the presentation of binaural auditory beats can affect psychomotor performance and mood.”
“That is what happens when you put an EEG on a, on a monk that's been meditating for decades. You'll see that when he's meditating, most of his EEG is in the [theta] stage. So it just artificially put people into a good meditative space. That's really all it does. … It doesn't make you go out of body. It doesn't force you to do anything. It just puts you in the same kind of altered state of consciousness as an experienced meditator.”
Important things to consider
Use stereo headphones and keep the channels separate
The effect needs a different tone in each ear. Over-ear wired stereo headphones are the Institute's preference, though good earbuds work. Speakers, a single earbud or a track mixed to one channel remove the binaural effect. Keep the volume comfortable.
Not all binaural-beat tracks are alike
Free tracks vary in carrier tone, mixing, background sound and length. A.J. Honeycutt notes that many producers make binaural beats and that Hemi-Sync is one brand among them. Walter says many people reach the Institute already listening to online beats. Whether the Institute's layered recordings do more than a well-made single beat is the Institute's claim, not a demonstrated fact.
Expect adaptation
Walter says that if you listen to the same simple beat for a long time the brain habituates and the following response fades. Variation helps, and so does using beats as a ladder rather than a crutch. If a track stops doing anything for you, change the exercise, the time of day or the approach instead of lengthening the session.
Falling asleep is common
Slow beats near theta and delta are built to relax, so drifting off is common at first. Walter suggests setting an intention to remember before you start and trying a guided meditation. If you fall asleep, that is information about the track, not a failure.
Four common misconceptions
Binaural beats are not a hidden sound you can hear on speakers; the beat exists only when each ear gets its own tone. They do not force an experience, since Monroe said the mind can accept or reject sound. More listening is not always better, because the brain adapts. And they do not work the same for everyone: Walter reports individual differences, and Campbell recalls annoyed volunteers alongside delighted ones.
A health caution
The Institute's publisher advises anyone with a tendency toward seizures, auditory disorders or adverse mental conditions, or who takes medications that affect relaxation, to consult a medical professional before listening. Binaural beats are a sound practice, not a treatment, and nothing here is medical advice.
What the evidence supports
The best-supported claim is modest: beats in certain ranges can shift arousal, attention or mood a little in some listeners. Claims about expanded awareness, healing or out-of-body travel rest on reports, not controlled studies. The authors of the 1998 Duke study themselves wrote that few scientific studies existed. Reviews of the wider literature are mixed, so keep your own notes before drawing conclusions.
Common questions
What is a binaural beat?
A binaural beat is a slow pulse your brain creates when each ear hears a slightly different tone through headphones. With 100 hertz in one ear and 104 in the other, you perceive a four-hertz rhythm, although no such sound exists in either ear. Dove described the effect in 1839. Monroe said his lab did not invent it but applied its frequency-following research to it, and the Institute's journal places the effect in the brain stem, where signals from both ears first meet, before it is conducted to the cortex.
Do binaural beats really change your brain waves?
Researchers have measured a very small EEG response at the beat frequency, which Atwater says appears only when many exposures are averaged. Whether the rest of the brain follows is less settled. In Atwater's two groups of roughly 20 volunteers, a 45-minute sequence with beats produced significant changes in alpha and delta activity, while the same tones without beats did not. Independent reviews of the broader literature are mixed, and a small EEG change is not the same as an altered state of awareness.
Which brain-wave frequencies does the Monroe Institute use?
The sources give examples rather than a table. Campbell says the lab aimed near four hertz, the delta-theta border, because Monroe reported that rate during vibrations; Monroe used eight hertz as an illustration of physical relaxation; and the Duke study used tapes with 16 and 24 hertz for alertness and 1.5 and 4 hertz for the slow condition. The sources give no frequency for each Focus level. Honeycutt says production follows Monroe's formulas and ratios, and the 1982 Army papers call the Institute's method patented. Real exercises also change frequency as they progress.
Are free binaural beats on YouTube the same as Hemi-Sync?
Not by the Institute's definition. Hemi-Sync is a brand with its own formulas, layered patterns, voice guidance and sound design, and Walter says simple beats lose their effect as the brain adapts. Campbell, a physicist who helped build the first tapes, says Monroe embedded the binaural beats in the sound he already had and that became Hemi-Sync, and he recommends plain binaural beats to beginners who are not good at meditating. The Institute's own 2000 test compared beats with no-beat tones, not layered recordings with plain beats, so whether the layering adds anything remains a claim. If you use free tracks, keep a log of what you notice.
Can binaural beats make you leave your body?
Campbell says no: they put people in the same altered state an experienced meditator reaches, and they do not make you go out of body or force you to do anything. Monroe likewise told a Gateway group that the program does not guarantee an out-of-body experience, and he put the rate near 15 percent of attendees during the program. Beats are a way to relax and focus; what you do with the state is the exercise.
How long should I listen, and can I get used to binaural beats?
Yes, the brain can adapt. Walter says sustained listening to a simple beat makes the brain tune it out, which is why Institute recordings change throughout. Campbell treats beats as training wheels for beginners and says to learn to reach the state without them. Practically, Walter mentions app tracks you can choose to run for 10 or 30 minutes, and Atwater's test tape ran 45. Stop if a track bothers you, and do not listen while driving.
In Monroe’s books
Summarized in our own words; the books are not reproduced on this site.
Far Journeys. Monroe walks through the binaural principle with a worked example of two tones a few hertz apart, explains that each ear's main signal crosses to the opposite hemisphere, and argues that this makes both halves of the brain cooperate to produce the third signal.
Keep exploring
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PODCASTS & VIDEOS
Watch and listen
Conversations and presentations connected to this topic. Each speaker brings their own experience and interpretation.
Podcast ·
Research and Out-of-Body Experiences with Robert A. Monroe
Tom Campbell
Expanding on Consciousness · Monroe Institute
A collaborator’s recollections
Campbell recalls meeting Bob Monroe, their early sound experiments and his own out-of-body experiences. Hear a collaborator’s account of the work behind the later programs.
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