What are binaural beats?
When each ear hears a slightly different steady tone, for example 195 Hz on the left and 205 Hz on the right, you do not hear two notes. You hear one tone that seems to pulse, here 10 times a second. That pulse is the binaural beat. It does not exist in the air; it is created in the brainstem, which compares the timing of sound between the two ears.
The effect was described by the Prussian physicist Heinrich Wilhelm Dove in 1839 and popularized by Gerald Oster in a 1973 Scientific American article. It works best with carrier tones below about 1,000 Hz and beat frequencies below about 30 to 40 Hz. Headphones are essential, because each ear must hear only its own tone.
The beat frequencies and what they are linked to
| Band | Beat | Associated with |
|---|---|---|
| Delta | 1 to 4 Hz | Deep, dreamless sleep |
| Theta | 4 to 8 Hz | Drowsiness, meditation, the edge of sleep |
| Alpha | 8 to 12 Hz | Relaxed, calm wakefulness |
| Beta | 13 to 30 Hz | Alert, active thinking |
| Gamma | 30 to 45 Hz | Concentration; 40 Hz is studied in memory research |
These bands describe the rhythms seen in brain recordings (EEG) during each state. The idea behind binaural beats is “entrainment”: that listening to a beat at a given rate nudges the brain toward that rhythm.
Do binaural beats work? An honest summary
The evidence is mixed. A 2019 meta-analysis in Psychological Research (Garcia-Argibay and colleagues) pooled 22 studies and found binaural beats had a small to moderate effect on anxiety, pain perception, memory and attention. But studies that measured brain activity directly have often failed to find clear entrainment, and many trials were small.
The famous 40 Hz research is also worth understanding precisely. Studies from MIT (Iaccarino and colleagues in Nature, 2016, and Martorell and colleagues in Cell, 2019) found that 40 Hz light flicker and sound clicks reduced Alzheimer’s-related changes in mice. Those used audible 40 Hz pulses, not binaural beats, and human trials are still underway.
A reasonable view: binaural beats are a pleasant, low-risk way to relax or focus, and some people find them very helpful. Do not expect dramatic effects, and do not use them instead of medical treatment.
How to use the generator
- Put on headphones. Without them, there is no binaural beat.
- Choose a preset: Delta or Theta before sleep, Alpha to unwind, Beta or Gamma for focus.
- Adjust Carrier tone if the hum feels too high or too low; 150 to 250 Hz is comfortable for most people.
- Keep a little brown noise or rain underneath. It makes a bare tone much easier to listen to.
- Set the timer. For sleep, 30 to 45 minutes of delta or theta is a common choice.
Safety
Binaural beats are safe for most people at a comfortable volume. People with epilepsy or a history of seizures should check with a doctor before using rhythmic audio stimulation. Do not use them while driving or doing anything that needs full attention, especially the delta and theta presets.
Frequently asked questions
Do I need headphones for binaural beats?
Yes. Each ear must hear its own tone for your brain to create the beat. Through speakers both ears hear both tones, and the effect disappears.
Which binaural beat is best for sleep?
Delta (1 to 4 Hz) and theta (4 to 8 Hz) are the usual choices before sleep. Combine with soft brown noise and a timer so the sound fades out.
Are binaural beats scientifically proven?
Partly. A 2019 meta-analysis found small to moderate effects on anxiety, pain, memory and attention, but evidence that they change brainwaves directly is inconsistent. Treat them as a relaxation aid rather than a proven therapy.
What is the difference between binaural and isochronic tones?
Binaural beats come from two tones, one in each ear, and need headphones. Isochronic tones are a single tone switched on and off at a set rate, so they work through speakers.
Can binaural beats be harmful?
At a normal volume they are safe for most people. People with epilepsy should ask a doctor first, and you should not listen while driving.