Tone generator: play any frequency
Set a frequency, choose a waveform and press “Play” – the tone comes straight from your browser. Use it to test speakers and headphones, to tune, or to roughly explore your hearing.
How it is calculated
How to use the tone generator
- Set the volume low first, especially with headphones.
- Enter a frequency, drag the slider or tap a quick pick. The semitone and octave buttons step in musical intervals.
- Choose a waveform: sine is a pure tone; square, triangle and sawtooth add overtones and sound sharper.
- Press “Play”. For a sweep, set start and end frequency and duration – the tone then glides smoothly across the octaves.
Note names and concert pitch
For every frequency the tool shows the nearest note in equal temperament and the deviation in cents (100 cents = 1 semitone). The reference is concert pitch A4 = 440 Hz, standardized as ISO 16:1975. One octave up doubles the frequency (A5 = 880 Hz); one semitone is a factor of 21/12. The sweep is exponential, so every octave takes the same time.
Protect your hearing
The WHO gives as a guide that at an average of 80 dB you can listen safely for up to 40 hours a week; at higher levels that time drops quickly. How loud a tone really is depends on device, headphones and frequency – the browser cannot measure it. So always start quietly and stop if it becomes unpleasant or your ears ring.
Limits
What you hear is limited by your speakers and your ears: small speakers often barely reproduce very low tones, and high frequencies become harder to hear with age. The generator does not replace a hearing test by a doctor or audiologist.
Frequently asked questions
Which frequencies can the tone generator play?
From 1 to 20,000 Hz. Whether you hear them depends on speakers, headphones and your hearing – many devices barely reproduce very low or very high tones.
What is the difference between sine and square?
A sine is a pure tone without overtones. Square, triangle and sawtooth contain extra overtones, so they sound brighter and harsher.
What frequency is concert pitch A?
440 Hz, set in ISO 16:1975. The tool uses this value as the reference for note names.
What is a sweep for?
A sweep glides from a start to an end frequency. It lets you hear where a speaker gets quieter, distorts or makes something rattle.
Can I test my hearing with it?
Only roughly, and without any information about loudness. A real hearing test needs calibrated equipment at a doctor or audiologist.
Sources and legal basis
- Wikipedia: A440 (pitch standard) – A4 = 440 Hz, genormt als ISO 16:1975
- MDN Web Docs – OscillatorNode.type (sine, square, sawtooth, triangle)
- MDN Web Docs – AudioParam.exponentialRampToValueAtTime()
- W3C – Web Audio API
- WHO – Deafness and hearing loss: Safe listening
As of:
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