Isochronic tones vs binaural beats: the differences, and which one to use

Isochronic tones vs binaural beats comes down to where the pulse is made. A binaural beat is made inside your head from two tones, one in each ear, so it needs headphones. An isochronic tone is one tone switched on and off at a steady rate, so the pulse is in the sound itself and works on any speaker. Both are used to nudge the brain towards a rhythm, such as 6 Hz for relaxation or 40 Hz for focus.

What is the difference between isochronic tones and binaural beats?

The main difference is that binaural beats are created by your brain, while isochronic tones are a pulse you hear directly. Here they are side by side:

	Binaural beats	Isochronic tones
How it’s made	Two steady tones, slightly apart, one in each ear	One tone, switched on and off at a set rate
Example (6 Hz)	200 Hz left, 206 Hz right	200 Hz tone, pulsing 6 times a second
Headphones	Required	Optional
How it sounds	A soft, slow wobble	A clear, rhythmic pulse
Amount of research	Most studies	Very few studies

A binaural beat is a trick of hearing. Neither ear hears a beat. Your brain compares the two tones and perceives the gap between them as a gentle pulse. If you’d like the full picture, start with what binaural beats are.

What are isochronic tones?

Isochronic tones are a single tone that turns on and off in evenly spaced pulses. “Isochronic” means “equal time”: every pulse and every gap is the same length. At 10 Hz, the tone sounds 10 times a second, with silence between each pulse.

Because the tone starts and stops so clearly, isochronic tones sound sharper and more noticeable than binaural beats. Some people find that rhythm easy to follow. Others find it tiring over a long session, especially at higher rates.

Do isochronic tones need headphones?

No, isochronic tones work just as well on speakers as on headphones. The pulse is a physical part of the sound wave, so it survives the trip through the air. Binaural beats are different: through a speaker, both tones reach both ears, they blend in the air, and the binaural effect is lost. Our guide to binaural beats without headphones explains what happens and what you can use instead.

Are isochronic tones better than binaural beats?

Neither has been shown to be better, and the evidence for isochronic tones is much thinner. A 2021 review found 17 controlled trials of good quality on sound and brainwaves. Fifteen used binaural beats. Only two used isochronic tones. The authors saw promising results but asked for better designed studies before firm conclusions.

There is one point in favour of a pulse that is in the sound itself. A 2005 lab study measured the brain’s response to a 40 Hz beat. The response to a binaural beat was smaller than the response to a beat in the sound itself, and it could only be detected with low tones: it became undetectable once the tones went above 3,000 Hz. A stronger brain response is not the same as a better result for sleep or focus, though. That part has not been tested head to head. For a wider look at the evidence, see do binaural beats work.

What are monaural beats?

Monaural beats are two close tones mixed together before they reach your ears. A 2015 review uses the example of 400 Hz and 440 Hz played together, which you hear as a 40 Hz beat in either ear, on headphones or speakers. Like isochronic tones, the pulse is real and in the sound. The same review notes that binaural beats are heard mainly with low tones, below 1,000 Hz, while monaural beats work across a wider range.

So there are three tools, not two:

• Binaural beats: soft, need headphones, the most studied.
• Monaural beats: a real beat between two tones, any speaker.
• Isochronic tones: a clear on and off pulse, any speaker.

Which should you use?

Use binaural beats when you can wear headphones and want something soft enough to fade into the background, such as for sleep or meditation. Use isochronic tones when you are listening on a speaker, or when you like a rhythm you can clearly hear, such as for a short focus session.

You can also combine them. Set both to the same frequency, for example 6 Hz, and keep the volume low. In Shimmr, both are generated live on your iPhone: the library has isochronic sessions from Delta to Gamma, and binaural sessions and Shifts for headphones.

Pulsing sound is gentle, but it is still a rhythm. If you have epilepsy or a seizure disorder, talk to your doctor before you try either. Never listen while driving.