Isochronic tones vs binaural beats

What are isochronic tones?

An isochronic tone is a single tone switched on and off at a steady rate: in one research team's words, "a pure tone that is turned on and off a fixed number of times per second" (Fry and colleagues). Switch a 432 Hz tone on and off ten times a second and you hear a 10 Hz pulse. Unlike a binaural beat, that pulse is really there in the air: a microphone records it, and any speaker plays it.

The name means equal in time. Every pulse lasts as long as the one before it, and so does every gap. The edges matter: a tone cut off abruptly clicks, so a well made isochronic tone fades in and out. The test tone we measure further down this page rises for 25 ms, holds for 25 ms, falls for 25 ms and rests for 25 ms, four quarters of one tenth of a second, the same in both ears.

How is a binaural beat different?

A binaural beat is two steady tones, one in each ear. Our 10 Hz alpha binaural beat plays 108 Hz in the left ear and 118 Hz in the right. Neither ear receives a pulse, yet you hear one, ten times a second, the difference between the two tones. Your brain makes it. One team that recorded the brain's response called it "a signal that is not present in the stimulus, but generated within the brain" (Schwarz and Taylor).

The beat forms in the brainstem, where the signals from your two ears first meet, and it needs low tones: Gerald Oster heard binaural beats only when the tone was below 1,000 Hz, as a 2015 review reports (Chaieb and colleagues). The pulse is also faint. When 12 adults matched a binaural beat against a tone with a real pulse in it, the match was a shallow pulse: "the perceptual strength of binaural beats is relatively weak, although all listeners perceived them" (Grose, Buss and Hall). For how binaural beats work and what the studies found, read do binaural beats work?

What is a monaural beat?

Mix those same two tones before they reach your ears, and they add and cancel in the air: the loudness swells and fades ten times a second. That is a monaural beat, also called an acoustic beat. In a monaural beat, "the actual interference of the sound waves is responsible for the beat percept", a 2023 review explains (Ingendoh, Posny and Heine).

So there are two places a beat can form. In one brain imaging study, two tones mixed and played to both ears beat in the inner ear, a "peripheral beat", while one tone in each ear beat in the brainstem, a "central beat"; both then reached the same areas of the cortex (Draganova and colleagues). An isochronic tone needs neither: its pulse is built into the sound before it plays.

Do isochronic tones need headphones?

No. The pulse is in the sound, so a phone speaker, a laptop or a room speaker plays it as well as headphones do. The binaural beat is the one that needs headphones, and we measured what happens when it does not get them.

We took the approved recording behind our 10 Hz binaural beat and traced its loudness. In each ear on its own the level holds still: across a minute it moves by 0.00003 dB, far below anything an ear can notice. Mix the two ears, as one speaker does, and the same recording swells and dips to silence ten times a second. It has become a monaural beat. The isochronic test tone goes further, because each of its pulses is followed by a real gap: it spends 35 per cent of the time below a tenth of its peak, against 6 per cent for the mixed binaural recording.

Download the measurements (CSV)

Your phone can do the mixing too. With Mono Audio switched on, an iPhone or AirPods play "the same content in both ears" (Apple), so a binaural beat arrives as a monaural one. Two speakers either side of you also let each ear hear both tones. For a binaural beat, use stereo headphones with mono switched off.

Which does the brain respond to more strongly?

A beat in the sound, in each head to head brain recording cited here. Play the same beat both ways and record the brain's steady response, and the binaural version comes out smaller: at 40 Hz (Schwarz and Taylor), at 3 and 6 Hz, where "beats-evoked oscillations were higher in amplitude in response to acoustic than to binaural beats" (Pratt and colleagues), and in recordings from inside the brain, where "the most prominent power increases were seen after stimulation with monaural 40-Hz beats" (Becher and colleagues).

The most careful comparison played 16 people binaural and monaural beats at 7 Hz and 40 Hz, at the same loudness. Both reached the brain, the monaural beat more strongly, and listeners described the binaural beat as weaker. Neither changed mood (Orozco Perez, Dumas and Lehmann).

The reason is depth. The brain's steady response to a pulsing sound grows "as the depth of modulation or the intensity increases" (Picton and colleagues). A binaural beat is a shallow pulse; an isochronic tone switches fully off, as deep as a pulse can go. In one study of 28 people, four minutes of a sound modelled on isochronic tones changed EEG power more than gamma binaural beats or white noise did (Dos Anjos and colleagues). A stronger response in a recording is not the same as a change in how you feel, though, and that is where the evidence thins.

What each study compared, and what it found

Study	Compared	Found
Schwarz and Taylor, 2005	A 40 Hz beat in the sound, and binaural	A smaller brain response to the binaural beat
Pratt and colleagues, 2010	3 and 6 Hz beats in the sound, and binaural	Larger responses to the beats in the sound
Becher and colleagues, 2015	Monaural and binaural beats from 5 to 80 Hz, recorded inside the brain	The largest rise after monaural 40 Hz beats
Orozco Perez and colleagues, 2020	Monaural and binaural beats at 7 and 40 Hz, 16 people	Monaural stronger; neither changed mood
Shumov and colleagues, 2023	Binaural, monaural and no beat at bedtime, 221 people	The same time to fall asleep
Bhusari and colleagues, 2023	Binaural, monaural and no music, 45 children at the dentist	Calmer scores with binaural beats; monaural weaker
Dos Anjos and colleagues, 2024	An isochronic style sound, gamma binaural beats and white noise, 28 people	The largest EEG change with the isochronic style sound
Akkurt and Ekici, 2026	Binaural beats, isochronic tones and silence, 90 people having a wisdom tooth removed	The same nerves scores in all three groups

Do isochronic tones work?

As a sound, yes: they make a clear pulse on any speaker. Whether they change how you feel or perform has barely been tested, and the few trials found little. In the largest, 90 people having a wisdom tooth removed heard binaural beats, isochronic tones or nothing, and "no significant between-group differences were observed" in how nervous they felt before and after; even so, 78.3 per cent of those who listened said they would choose sound again next time (Akkurt and Ekici).

Ten minutes of isochronic beats added to music made no difference to 11 trained cyclists (Fry and colleagues). In a four week study of teenagers, the nine who only listened to binaural beats and isochronic tones "did not see statistically significant improvements" (Yadav and colleagues). These are small studies, so they cannot rule a small effect out. They do not show one either.

Do binaural beats work?

The research is larger and just as mixed. Of 14 EEG studies in a 2023 review, five found brain rhythms following the beat, eight did not and one was mixed (Ingendoh, Posny and Heine). When 221 people fell asleep to the same sound with a binaural beat, a monaural beat or no beat at all, the beat made no difference to how long it took (Shumov and colleagues). Among 45 children at the dentist, those who heard binaural beats gave calmer scores than those with no music, and the monaural group's difference was weaker (Bhusari and colleagues). Our guide do binaural beats work? covers the reviews in full.

Which should you choose?

Choose by how you listen and what you like to hear, not by a promised state.

• Headphones on, and you enjoy a pulse that seems to sit inside your head: a binaural beat. Every recording in our Binaural Beats collection keeps 108 Hz in the left ear; the 10 Hz alpha beat is a clear, gentle pulse to start with.
• A speaker, a phone on the table or one earbud: a beat that lives in the sound, an isochronic tone or a monaural beat. A binaural beat on a speaker turns into a monaural beat anyway, as the chart shows.
• A faster pulse: most of the brain recordings above used 40 Hz, near where the brain's steady response is largest. Our 40 Hz gamma binaural beat plays that rate, and the gamma waves guide explains what that band means.

For what alpha means in brain recordings, read alpha waves and binaural beats, and for every band side by side, brainwave frequencies.

Are isochronic tones safe?

Keep the volume low. The World Health Organization advises keeping "the volume below 60% of maximum on your device", and puts the safe limit for 80 dB at 40 hours a week (WHO). A 2024 review found no study reporting side effects from binaural beats, advised staying below 85 dB, and recommended that anyone with epilepsy ask their doctor before trying them (Mirmohamadi and colleagues). If a pulse starts to feel harsh, turn it down or stop.

Sources and limits

Isochronic tones have far less research than binaural beats, and most of the studies above are small and short. Several compared beats in the sound with binaural beats at 40 Hz, not 10 Hz. Brain recordings show how strongly the brain follows a pulse; they do not show a change in how anyone feels. Our measurements describe our own recording and our own test tone, not every track sold under these names, and no study has tested either of them.

1. Orozco Perez, Dumas and Lehmann, Binaural Beats through the Auditory Pathway, eNeuro, 2020: 16 people, monaural beats stronger, no change in mood.
2. Chaieb and colleagues, Auditory Beat Stimulation and its Effects on Cognition and Mood States, Frontiers in Psychiatry, 2015: monaural and binaural beats compared.
3. Ingendoh, Posny and Heine, Binaural beats to entrain the brain? A systematic review, PLOS ONE, 2023.
4. Draganova and colleagues, Cortical steady state responses to central and peripheral auditory beats, Cerebral Cortex, 2008.
5. Schwarz and Taylor, Human auditory steady state responses to binaural and monaural beats, Clinical Neurophysiology, 2005.
6. Pratt and colleagues, A comparison of auditory evoked potentials to acoustic beats and to binaural beats, Hearing Research, 2010.
7. Becher and colleagues, Intracranial EEG power and phase synchronization changes during monaural and binaural beat stimulation, European Journal of Neuroscience, 2015.
8. Picton and colleagues, Human auditory steady state responses, International Journal of Audiology, 2003: why a deeper pulse draws a larger response.
9. Grose, Buss and Hall, Binaural beat salience, Hearing Research, 2012: a weak percept.
10. Dos Anjos and colleagues, Brain wave modulation and EEG power changes during auditory beats stimulation, Neuroscience, 2024: 28 people.
11. Akkurt and Ekici, binaural beats and isochronic tones in a randomised controlled trial, Int J Oral Maxillofac Surg, 2026: 90 people.
12. Fry and colleagues, Music augmented with isochronic auditory beats or vibrotactile stimulation, Frontiers in Human Neuroscience, 2021: 11 cyclists.
13. Yadav and colleagues, Using Heartfulness Meditation and Brainwave Entrainment to Improve Teenage Mental Wellbeing, Frontiers in Psychology, 2021.
14. Shumov and colleagues, binaural or monaural beats and sleep latency, Zhurnal Nevrologii i Psikhiatrii, 2023: 221 people.
15. Bhusari and colleagues, no music, monaural beats and binaural beats at the dentist, J Indian Soc Pedod Prev Dent, 2023: 45 children.
16. Mirmohamadi and colleagues, a review of binaural beats and the brain, 2024: volume and epilepsy.
17. World Health Organization, Deafness and hearing loss: safe listening.
18. Apple, Play the same sound in both of your AirPods: Mono Audio.