What are binaural beats and how do they work?

Binaural beats are a soft, steady pulse that you hear when each ear gets a tone of a slightly different pitch. Play 200 Hz in your left ear and 210 Hz in your right, and you perceive a beat at the difference: 10 Hz. Here is what binaural beats are, how they work, what people use them for, and what the evidence really says.

What are binaural beats?

A binaural beat is a pulse your brain creates from two separate tones, one in each ear. “Binaural” simply means “with two ears”. Neither tone has a pulse on its own. The beat only appears when your brain compares the two signals and notices that they are slightly out of step.

The effect was first described by the German physicist Heinrich Wilhelm Dove in 1839. It reached a wide audience in 1973, when the biophysicist Gerald Oster explained it in “Auditory Beats in the Brain” in Scientific American.

How do binaural beats work?

Binaural beats work because your brain, not the air, mixes the two tones. Sound from each ear travels to a part of the brainstem that compares timing between the ears. It uses this to tell where a sound comes from. When the two pitches differ by a few hertz (cycles per second), that comparison drifts in and out of step, and you hear the drift as a beat.

Left ear	Right ear	Beat you hear	Band
200 Hz	203 Hz	3 Hz	Delta
200 Hz	206 Hz	6 Hz	Theta
200 Hz	210 Hz	10 Hz	Alpha
200 Hz	220 Hz	20 Hz	Beta

The effect works best with tones below about 1,000 Hz and differences of about 1 to 30 Hz. That range overlaps the main bands of brain activity: delta (0.5 to 4 Hz), theta (4 to 8 Hz), alpha (8 to 12 Hz) and beta (13 to 30 Hz). Above about 30 Hz the beat fades into a rough tone.

Why do you need headphones for binaural beats?

You need headphones because each ear must hear only its own tone. Through a speaker, both tones reach both ears and mix in the air. You then hear an ordinary wobble in loudness, an acoustic beat, which is a different thing. Any wired or wireless headphones or earbuds work, and noise cancelling is not needed. If you cannot wear headphones, there are other ways to listen.

What are binaural beats good for?

People mainly use binaural beats for four things:

• Sleep: slow delta beats of 2 to 4 Hz, often after a glide down from alpha. See binaural beats for sleep.
• Focus: beta beats of about 14 to 20 Hz during work or study.
• Relaxation: alpha and theta beats of 4 to 12 Hz to ease tension.
• Meditation: theta beats of 4 to 8 Hz to settle into a session.

The idea behind all of these is “entrainment”: the hope that your brain activity drifts towards the rhythm it hears. The evidence for that is mixed, so it is worth knowing what studies have found.

Do binaural beats actually work?

Binaural beats have measurable but modest effects in some studies, and none in others. A 2018 meta-analysis that pooled earlier trials found a medium overall effect on memory, attention, anxiety and pain. A 2015 review of beat stimulation on thinking and mood also found promising but inconsistent results.

The brain side is less clear. A 2023 systematic review looked at 14 studies that recorded brain activity. Only 5 found that the brain followed the beat, 8 found that it did not, and 1 was mixed. The beat you hear is real. Whether it reliably changes your brainwaves is still an open question. Our article on whether binaural beats work goes deeper.

Binaural beats are low risk for most people. If you have epilepsy or a seizure disorder, talk to your doctor before you try them. Never listen while driving or doing anything that needs your full attention.

How can you try binaural beats yourself?

Two minutes with headphones is enough to hear the effect. Put on headphones, set the volume low, and play a beat in the alpha range, around 10 Hz. At first you hear two steady tones. Within a minute most people notice a slow, soft pulse that seems to sit in the middle of the head. Take one earbud out and the pulse disappears.

Shimmr generates binaural beats live on your iPhone or iPad, with sessions from Delta to Gamma. In Sound Canvas you can drag a tone and hear its beat change while it plays. You can also compare them with isochronic tones, which pulse without needing headphones.