An online tone generator for testing, tuning and experimenting
This Tone Generator turns your browser into a signal generator. Pick a sine, square, sawtooth or triangle wave, dial in any frequency from 1 Hz to 22,000 Hz with the logarithmic slider, the number box or the musical note picker, and press Play. You can send the tone to the left speaker, the right speaker or both, sweep smoothly from one frequency to another, create binaural beats for headphones, and download any of these as a WAV file.
People use it to check speakers and headphones, find the resonant frequency of a room or a rattling panel, test how high they can still hear, tune instruments by ear, calibrate audio equipment, make test signals for electronics projects, and produce reference tones for music lessons and sound design.
Tones are synthesised in real time by the Web Audio API on your own device, so there is no download, no latency from a server and nothing to install.
How to use the Tone Generator
- Choose a waveform: Sine is the pure tone used for testing; square, sawtooth and triangle add harmonics.
- Set the frequency with the slider, type it in Hz, or pick a note such as A4 (440 Hz). Use ÷2 and ×2 to jump octaves.
- Keep the volume low to begin with — 25% is the default — and raise it only as needed.
- Optionally choose Left only or Right only to test one speaker, or switch Mode to Frequency sweep or Binaural beat.
- Press Play. Change anything while it plays and the sound updates instantly. Press Stop when finished.
- Set a length in seconds and press Download WAV to save the tone as a 16-bit, 44.1 kHz stereo file.
Tone Generator features
Four waveforms
Band-limited sine, square, sawtooth and triangle oscillators that stay clean even at high frequencies, with a live waveform preview.
Full audible range and beyond
From 1 Hz sub-bass pulses to 22 kHz, with a logarithmic slider so the musically useful range is easy to reach and 1 Hz fine-tune buttons.
Note picker
Select any note from C1 to C8 to get its equal-temperament frequency at A4 = 440 Hz or your own reference (432, 442, 415…); the display shows the nearest note and cents for any frequency.
Sweeps and binaural beats
Sweep exponentially between two frequencies over 1–120 seconds, repeating or once, or play two slightly different sine tones to each ear.
Stereo channel select
Route the tone to the left, right or both channels to check wiring, balance and stereo imaging.
Exact WAV export
Files are rendered offline with the same oscillators, with 10 ms fades to prevent clicks, up to 10 minutes long.
Common test frequencies
| Frequency | What it is used for |
|---|---|
| 20–60 Hz | Subwoofer and room-mode tests; below ~40 Hz most small speakers produce nothing |
| 100 Hz | Checking for buzzing panels and loose fittings |
| 440 Hz | Concert pitch A4 — tuning reference for orchestras and guitars |
| 1,000 Hz | Standard calibration and level-setting tone in broadcasting and studios |
| 3,000–4,000 Hz | Peak sensitivity of human hearing; also the range of most tinnitus tones |
| 8,000–12,000 Hz | Hearing drops here first with age or noise damage |
| 17,000–20,000 Hz | Upper limit of hearing for teenagers; most adults over 30 cannot hear 17 kHz |
Waveforms and harmonics
A sine wave contains a single frequency and is the only truly “pure” tone — use it for hearing checks and calibration. A square wave adds every odd harmonic (3×, 5×, 7×…) at decreasing levels and sounds hollow and buzzy, like an old video game. A sawtooth has every harmonic and sounds bright and brassy; it is the raw material of most synthesiser sounds. A triangle wave has odd harmonics that fall off much faster, so it sounds like a softer, slightly nasal sine.
Because square and sawtooth waves carry energy far above their fundamental, a 1 kHz sawtooth is harsher on the ears and on small tweeters than a 1 kHz sine at the same volume setting. Keep the level down when exploring them.
Binaural beats and sweeps
A binaural beat happens when each ear hears a slightly different frequency — say 200 Hz on the left and 210 Hz on the right. The brain perceives a pulsing 10 Hz “beat” that does not exist in either signal. The effect only works over headphones, since the two tones must stay separate. Presets cover the delta (2 Hz), theta (6 Hz), alpha (10 Hz), beta (20 Hz) and gamma (40 Hz) bands popular in relaxation and focus playlists. Claims about health effects are not well established; treat them as a listening experiment, not a treatment.
A frequency sweep moves smoothly between two frequencies on an exponential curve, so every octave takes the same amount of time. Sweeping 20 Hz to 20 kHz over 20 seconds is the classic way to reveal rattles, resonances and the point where your hearing or your speakers give out. For a broadband signal instead of a single moving tone, try the Noise Generator; to see the note names of any frequency, the Online Tuner listens back through your microphone.
Tone Generator FAQ
Is the tone generator free to use?
Yes, it is free, needs no account and has no limits on frequency, duration or downloads.
Is it safe to listen to these tones?
At sensible volumes, yes. Pure tones concentrate all their energy at one frequency, so start low, avoid long sessions at high level, and stop if you feel any discomfort or ringing. Never test the limits of your hearing at high volume.
Why can’t I hear anything above 16 kHz?
Hearing sensitivity at high frequencies drops naturally with age and noise exposure, and many small speakers and Bluetooth codecs roll off above 15–16 kHz. Try wired headphones before concluding it is your ears.
Which frequency is the note A?
A4, the A above middle C, is 440 Hz by international standard. Each octave doubles: A3 is 220 Hz, A5 is 880 Hz. Pick any note from the note list to set it exactly, or see every note in the note frequency chart.
Can I download the tone as MP3?
The tool exports WAV, which is lossless and plays everywhere; MP3 encoding is not available in browsers. A 10-second stereo WAV is about 1.7 MB.
Why does the tone sound distorted on my phone?
Small phone speakers cannot reproduce low frequencies and may buzz when pushed; square and sawtooth waves also contain strong harmonics. Lower the volume or use headphones for a clean result.