Binaural Beat Generator
Generate binaural beats by playing two slightly different sine tones to each ear, using the Web Audio API. Use headphones. Nothing is uploaded.
Use headphones — the two ears must hear different tones for the beat to form.
Pure browser JavaScript — uses the Web Audio API (two OscillatorNodes + StereoPanner).
How to use this tool
- Put on headphones (binaural beats require a different tone in each ear).
- Set the carrier frequency and the beat (difference) frequency.
- Click Play; the left ear gets carrier minus half the beat, the right ear gets carrier plus half.
Generate binaural beats by playing two slightly different sine tones to each ear, using the Web Audio API. Use headphones. Nothing is uploaded.
How it works
A binaural beat is an auditory illusion created when two pure sine tones of slightly different frequencies are played separately to each ear. The brain perceives a third tone at the frequency equal to the difference between the two. For example, a 200 Hz tone in the left ear and a 210 Hz tone in the right ear produce a perceived 10 Hz beat.
This tool generates both carrier tones in real time using the Web Audio API and routes them to left and right stereo channels. You set the carrier frequency (the base tone, typically 100-400 Hz) and the beat frequency (the difference between the two tones, typically 1-40 Hz). Headphones are required for the effect to work -- speakers mix the audio before it reaches your ears, preventing the illusion.
Binaural beats are used by some people to aid concentration, meditation, or relaxation. Many users find beats in the alpha range (8-14 Hz) helpful for focus and those in the theta/delta range (1-8 Hz) helpful for sleep or deep relaxation. Results vary between individuals.
Worked example
Set up an alpha-wave beat for light focus
- Put on stereo headphones.
- Set the carrier frequency to 200 Hz.
- Set the beat frequency to 10 Hz (producing a perceived 10 Hz beat in the alpha range).
- Click Play and reduce the volume to a comfortable background level.
- Work or study while the beat plays quietly.
A 10 Hz binaural beat in the alpha range, which some users find promotes relaxed alertness suitable for reading or writing.
Common mistakes to avoid
- Trying to use the tool through speakers instead of headphones -- the binaural effect requires each tone to reach only one ear.
- Setting the beat frequency above 40 Hz, where the perceived beat effect weakens and may become inaudible or unpleasant.
- Playing at high volume for extended periods, which can cause ear fatigue -- keep the volume low and take breaks.
Key terms
- Carrier frequency
- The base frequency of the sine tones played to each ear. Typically set between 100 and 400 Hz for a comfortable listening experience.
- Beat frequency
- The difference between the two carrier tones. This is the frequency of the perceived pulsing sensation inside the head.
- Alpha waves
- Brainwave oscillations in the 8-14 Hz range, often associated with relaxed but awake mental states.
Frequently asked questions
- Why do I need headphones?
- Each ear must receive a slightly different frequency. The perceived 'beat' is created in the brain from the difference, which only works when the tones aren't mixed in the air.
- Are binaural beats a medical treatment?
- No. This is an audio toy; it is not a medical device and makes no health claims.