How binaural beats work
If your left ear hears a tone at 200 Hz and your right ear hears one at 210 Hz, you do not hear two separate tones. Your brain combines them and you perceive a soft "wah-wah" pulsing 10 times per second: the 10 Hz difference between the ears. That perceived pulse is the binaural beat. It is created inside your head, which is why binaural beats only work with headphones.
The effect was described by the physicist Heinrich Wilhelm Dove in 1839 and became widely known after Gerald Oster wrote about it in Scientific American in 1973. Today it is used in many relaxation, sleep and focus recordings, usually mixed under music, rain or noise.
What alpha, theta and delta mean
The brain produces electrical rhythms that can be measured with an EEG. Scientists group them by speed: delta waves (about 0.5 to 4 Hz) dominate deep sleep; theta waves (4 to 8 Hz) appear in drowsiness, light sleep and some meditation; alpha waves (8 to 12 Hz) are typical of relaxed wakefulness, for example with your eyes closed; beta waves (13 to 30 Hz) go with active thinking and concentration.
Binaural recordings are named after these bands. A "theta binaural" uses a difference between the ears inside the theta range, such as 5 Hz. The idea behind it is called entrainment: that listening to a pulse at a given speed nudges your brain toward the same rhythm.
| Delta | Theta | Alpha | |
|---|---|---|---|
| Range | About 0.5–4 Hz | 4–8 Hz | 8–12 Hz |
| Linked in the brain to | Deep sleep | Drowsiness, light sleep, deep meditation | Relaxed wakefulness, eyes closed |
| Typical use in recordings | Falling into deep sleep | Falling asleep, meditation | Unwinding, calm focus, meditation |
| Example in our sampler | 2 Hz (200 / 202 Hz) | 5 Hz (200 / 205 Hz) | 10 Hz (200 / 210 Hz) |
What the research says
The evidence is mixed. A 2019 meta-analysis that pooled 22 studies found that binaural beats had a small to moderate effect on anxiety, memory, attention and pain perception, although the studies varied a lot in how they were done. A 2023 systematic review looked at whether binaural beats actually change brain waves, as entrainment suggests, and found inconsistent results: some studies supported it, others found the opposite or no effect.
In practice, that means binaural beats may help some people relax, settle into meditation or fall asleep, but they are not a reliable way to switch your brain into a particular state, and they are not a treatment for insomnia, anxiety or any other condition. If you enjoy them, that comfort is reason enough to use them.
How to listen
- Use headphones. Over-ear headphones are the most comfortable for long sessions; for sleep, choose soft, flat headphones or a sleep headband.
- Keep the volume low, just enough to hear the pulse under the music or noise.
- Pick the band for what you want: alpha to unwind or meditate, theta to drift off, delta for deep night listening.
- Give it 15 to 30 minutes, lying or sitting comfortably with your eyes closed.
- Do not listen while driving or doing anything that needs your full attention.
Who should be careful
If you have epilepsy or a seizure disorder, ask your doctor before listening to binaural beats or other rhythmic stimulation. Stop if you feel dizzy, uneasy or get a headache. If you cannot use headphones, try isochronic tones or monaural beats, where the pulse is already in the sound and works from a speaker.
Binaural beats in Sonovana videos
Our binaural videos say so in the title and remind you to use headphones. The binaural layer is mixed softly under ambient music, rain or nature sounds, and we name the band (alpha, theta or delta) or the frequency difference that is really in the audio.