10 Hz: the alpha frequency and how to hear it

10 Hz means ten cycles a second. As sound it is infrasound, below about 20 Hz, where hearing stops giving a sense of pitch. In the brain, 10 Hz sits in the middle of the alpha band, the rhythm that grows when you rest with your eyes closed. A 10 Hz binaural beat plays 108 Hz to one ear and 118 Hz to the other.

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Open the 10 Hz page

Ten long gold ribbons of light on a deep violet ground, spaced evenly from top to bottom in one steady, symmetric wave — Ten ribbons in alpha gold, one for each cycle a second, drawn in code: one steady wave from edge to edge, as the recording holds 10 Hz for nine hours.

What does 10 Hz mean?

10 Hz means ten cycles a second. The hertz counts how many times something repeats in each second, so one cycle of a 10 Hz wave lasts 100 milliseconds. The number says nothing about what is repeating: a sound wave, a flickering light and an electrical rhythm in the brain can all run at 10 Hz, and each behaves differently.

Most people who search for 10 Hz are asking about two of them. One is the brain's alpha rhythm, which runs close to ten waves a second when you rest with your eyes closed. The other is the 10 Hz binaural beat, a pair of tones you can hear that make a beat at that rate. This guide takes each in turn, with Harmonance's own measurements of both.

Can you hear a 10 Hz sound?

Not as a tone. Sound below 20 Hz is called infrasound, and a review of hearing at low and infrasonic frequencies describes what happens on the way down: pure tones become gradually less continuous, the sense of a tone stops around 20 Hz, and below 10 Hz the single cycles of the sound can be perceived. Infrasound is perceived only when it is loud enough, and then often as a sense of pressure at the eardrums.

So a 10 Hz binaural beat does not play a 10 Hz sound. It plays two tones well inside the range you hear as pitch, 108 Hz and 118 Hz, and the rate of 10 a second comes from the difference between them.

Why is 10 Hz linked to the brain?

Because the first rhythm recorded from a human scalp ran at about ten waves a second. Hans Berger published the first article on the human EEG, electroencephalography, in 1929. The first scalp recording he published was of his son Klaus, aged 15, resting with his eyes closed, and under it Berger drew a 10 Hz wave to show that the main rhythm ran at around 10 Hz (Babiloni and colleagues' account of Berger's work). He called that rhythm primary at first, and a year later named it alpha.

The clinical glossary of the International Federation of Clinical Neurophysiology still describes the alpha rhythm the way Berger saw it: 8 to 13 Hz, during wakefulness, largest over the back of the head, best seen with the eyes closed and the body relaxed, and blocked or weakened by attention, especially visual, and by mental effort (IFCN glossary). 10 Hz sits near the middle of that band. The guide to alpha waves follows the band in more detail, and the guide to brainwave frequencies sets it beside the others.

What does a 10 Hz rhythm look like in a real brain?

We redrew Berger's comparison from open recordings. The EEG Motor Movement/Imagery Dataset, shared on PhysioNet by the team behind the BCI2000 recording system, starts each volunteer's session with two one-minute rests, one with the eyes open and one with them closed, recorded from 64 electrodes at 160 samples a second.

Twelve volunteers in it have an alpha rhythm that peaks at exactly 10.00 Hz with their eyes closed. We took the one whose alpha rose most when their eyes closed and drew two seconds from the electrode over the back of the head: the two seconds of the eyes-closed minute where alpha was strongest, and the same two seconds of the eyes-open minute, both on one scale.

Two seconds of one person's EEG at the back of the head, small with eyes open and a regular rhythm with eyes closed, above a 10 Hz wave — With the eyes closed, one volunteer's EEG swung between -190 and 166 microvolts in a regular rhythm: 19 crests in two seconds, a median of 100 milliseconds apart. With the eyes open, the same two seconds stayed between -76 and 92 microvolts. The wave beneath runs at exactly 10 Hz, as Berger drew one under his son's trace.

One volunteer, eyes open and closed
Measure	Eyes open	Eyes closed
Alpha power over the minute	148.8 µV²	4,134.5 µV²
Alpha peak over the minute	9.50 Hz	10.00 Hz
Range in the two seconds drawn	-76 to 92 µV	-190 to 166 µV
Spread in the two seconds (standard deviation)	28.5 µV	81.1 µV

With the eyes open the trace is small and irregular. Once they close, a regular rhythm takes over at more than twice the size, strongest at 9.86 Hz in these two seconds. Over the whole minute this volunteer's alpha power, measured over the back of the head, was 27.8 times higher with the eyes closed. Berger's 10 Hz line fits the closed trace closely; by the last half second its crests fall a little after the gridlines, because this stretch runs slightly slower than 10.

Is everyone's alpha rhythm at 10 Hz?

No: 10 Hz is typical, not universal. In a study of 1,498 healthy people aged 6 to 86, the frequency of the alpha rhythm rose through childhood and fell in old age, and about 44 per cent showed more than one distinct alpha rhythm (Chiang and colleagues).

The open recordings show the same spread. When Harmonance measured them for the alpha guide, 107 volunteers had a clear alpha peak with their eyes closed, running from 7.75 to 13 Hz, with the middle volunteer at 10.25 Hz. 57 of the 107 peaked within half a hertz of 10, and 12 at exactly 10.00 Hz. So 10 Hz is a fair round number for the alpha rhythm, and an exact one for few people.

How does a 10 Hz binaural beat work?

A 10 Hz binaural beat plays one steady tone in each ear, 10 Hz apart, and your hearing turns the difference into a beat. Harmonance's plays 108 Hz in the left ear and 118 Hz in the right. Each ear hears a low, even hum; together they make a pulse 10 times a second that is in neither ear alone.

The beat is made in the brainstem. Neurons of the superior olivary complex, which respond to differences in timing between the two ears, fire at the rate of the difference and create the beat, and Oster found binaural beats were heard only with tones below about 1,000 Hz (Chaieb and colleagues' review). Up to 20 Hz, a binaural beat is heard as a tone fluctuating in loudness (a 2023 systematic review). Played through a speaker, both tones reach both ears and mix in the air instead; binaural beats and isochronic tones explains the difference.

One tenth of a second of 108 Hz in the left ear and 118 Hz in the right, then the brainstem, the auditory cortex and the alpha rhythm — In 100 milliseconds the left ear hears 10.8 waves of 108 Hz and the right ear 11.8 waves of 118 Hz, so the right gains one whole wave and the two fall in and out of step 10 times a second. The brainstem makes the beat from that difference; whether the brain's own alpha rhythm follows it is the open question.

The arithmetic is easy to redo. 118 minus 108 is 10, so every 100 milliseconds the right ear's tone gains exactly one wave on the left's. Each beat spans 10.8 waves of the left ear's tone, and nine hours hold 324,000 beats.

What is in Harmonance's 10 Hz recording?

Two pure tones and nothing else, for nine hours: 108 Hz in the left ear and 118 Hz in the right, from the first second to the last. The 10 Hz alpha binaural beat plays it free, with no ads, and it is part of the Binaural Beats collection.

The uploaded nine-hour master, measured
Moment	Left and right ear	Beat
First second	108.00 and 118.00 Hz	10.00 Hz
Halfway, 4 h 30 min	108.00 and 118.00 Hz	10.00 Hz
Last second	108.00 and 118.00 Hz	10.00 Hz

Read from the decoded audio of the uploaded master, 6,481 readings in all. The largest difference from the planned tones was 0.00065 Hz.

We measured the uploaded master itself, not only the recipe. Its loudness reads -23 LUFS, and its peaks stay more than 21 dB below the loudest a recording can go. In each channel the other ear's tone sits at least 80 dB down, so the two tones meet only in your hearing, never in the file. The steady rate is a listening choice: no study has played a 10 Hz beat for nine hours.

Does a 10 Hz binaural beat change your brainwaves?

Studies that recorded the brain disagree. The 2023 review looked at 14 EEG studies of binaural beats: five fitted entrainment, the idea that brain rhythms fall into step with the beat, eight did not and one was mixed. Studies that used a beat at or near 10 Hz fall on both sides.

EEG studies of beats at or near 10 Hz, oldest first
Study	What people heard	What was found
Vernon and colleagues	22 people, a 10 Hz or a 20 Hz beat in ten one-minute blocks	The EEG did not follow either beat
Gao and colleagues	13 people, five-minute beats at 1, 5, 10 and 20 Hz	During the 10 Hz beat the share of theta and alpha rose and beta fell; no clear entrainment
Solcà and colleagues	Beats at 10 Hz and 4 Hz, against the same tones played to both ears	Both raised alpha-band synchrony between the two hearing areas; a listening test straight after showed no change
López-Caballero and Escera	14 people, three-minute beats in five bands, the alpha one at 8.97 Hz	No band of the EEG changed, with binaural or with ordinary beats
Kim and colleagues	23 adults, 250 Hz in the left ear and 260 Hz in the right	More alpha power than with the same tones made without a beat, everywhere but over the temporal lobes

Five small studies that recorded the EEG while people heard a beat at or near 10 Hz. Three saw more alpha, or more alpha synchrony, during the beat; two saw no change.

Even where alpha rose, the authors read it carefully. Solcà and colleagues saw the same rise in alpha synchrony with a 4 Hz beat as with a 10 Hz one, and read it as the brain combining the two ears rather than following the beat. A 10 Hz beat is real to hear; whether it moves the brain's own alpha rhythm is not settled.

What are the benefits of 10 Hz binaural beats?

None is established, and the few studies of what a 10 Hz beat does to thinking point different ways. In a study of 24 students who heard a 10 Hz beat, a 40 Hz beat and a steady control tone in three sessions, the beats changed scores on a divergent thinking task, which asks for many answers, and not on a convergent one, which asks for one. Students with a low spontaneous blink rate did better with the 10 Hz beat; those with a high blink rate were unaffected or did worse.

In a study of 30 people who heard 10 Hz and 40 Hz beats in separate sessions, a computer recognised their P300 brain response less accurately after the 10 Hz beat and more accurately after the 40 Hz one, and during the 10 Hz beat a measure of the EEG moved the way the authors read as lower arousal. A 2019 meta-analysis pooled 22 studies of many beat rates and found a medium average effect, so it cannot say what a 10 Hz beat does on its own. Listen because you like how it sounds, and notice for yourself.

How do you listen to a 10 Hz binaural beat?

Use headphones. The beat forms only when each ear gets its own tone. Turn off spatial audio or head tracking, and check that left and right are the right way round.
Keep it quiet. The World Health Organization's safe listening advice gives 80 dB as safe for up to 40 hours a week and suggests keeping a device below 60 per cent of its maximum. Nine hours a day for a week is 63 hours, so for a session this long, keep the level well below that.
Try it with your eyes closed. Alpha is largest when you rest with your eyes closed, so sit quietly with the 10 Hz beat for ten minutes, eyes shut, then sit the same way in silence, and notice what you notice. The Feeling disconnected? page sets it beside two other tones people reach for.
Keep a practice. In Studio you can set a timer and save the mixes you come back to.
Stop when you want to. Do not listen while driving or doing anything that needs your full attention, and take the headphones off if anything feels uncomfortable.

If you prefer a beat that moves, the Alpha Brainwave Session falls from 12 to 9 Hz over nine hours. The guide to binaural beats covers what the reviews found across every rate, and the guide to beta waves follows the band just above alpha.

Sources and limits

The chart shows two seconds of one volunteer, chosen by a stated rule from an open dataset: it shows what an alpha rhythm near 10 Hz looks like and how it grows when the eyes close, not what sound does to it. The alpha peaks come from the same open recordings. The studies of 10 Hz binaural beats are few and small, used different designs and listening times, and none tested Harmonance's nine-hour recording.