How to use the tone generator
- Turn your device volume down.
- Choose a Waveform: Sine, Square, Sawtooth or Triangle.
- Enter the Frequency in Hz (1 to 22,000, default 440). The display above shows the frequency and its note name, such as “440 Hz · A4”.
- Set Volume (1–100%, default 25%) and press Play. Press Stop to end with a short fade.
- To save the tone, set Export length (0.1 to 3,600 seconds, default 5) and press Export WAV.
What it does and when to use it
A clean tone is a basic tool for many jobs: tuning an instrument to A 440, checking a speaker or subwoofer at a given frequency, finding a rattle in a car or room, testing an audio cable or mixer channel, demonstrating frequency and pitch in a science class, or making a beep for a video or alarm. The export makes a file you can play on any device, or drop into an editor.
For testing each speaker side separately, use the speaker and headphone tester. For relaxing background sound instead of a pitch, try the noise generator. To see what frequencies a speaker or microphone actually produces, watch the spectrum analyser while this plays.
How it works
Live playback uses your browser’s Web Audio oscillator on your device, connected through a gain stage that fades in over 30 ms so it starts without a click. The export runs in a worker: it calculates the chosen waveform sample by sample at 44,100 Hz, scales it by the volume, adds 10 ms fades at both ends, and writes a mono 16-bit WAV. Mono WAV at this rate takes about 5 MB per minute, so a one-hour export is roughly 300 MB.
The note name uses A4 = 440 Hz: note number = 69 + 12 × log₂(frequency ÷ 440), rounded, with the difference shown in cents. The period is 1000 ÷ frequency milliseconds.
Worked examples
From the tool’s own output:
| Settings | Note | Period | File |
|---|---|---|---|
| 440 Hz, Sine | A4 | 2.273 ms | tone-sine-440hz-5s.wav (430.7 KB) |
| 261.63 Hz, Square | C4 | 3.822 ms | tone-square-261.63hz-5s.wav |
| 1000 Hz, Sine, 10 s | B5 (+21 cents) | 1 ms | tone-sine-1000hz-10s.wav |
| 50 Hz, Sawtooth, 2 s | G1 (+35 cents) | 20 ms | tone-sawtooth-50hz-2s.wav |
Note that 1 kHz, a common test frequency, is not a musical note; it sits 21 cents above B5.
Limits and tips
- The exported square, sawtooth and triangle waves are calculated directly and are not band-limited, so at high frequencies they can contain aliasing (extra tones that should not be there). The live oscillator does not have this issue. For high-pitched test files, use a sine.
- Above 11 kHz or so, square and sawtooth waves lose their character because most overtones are above hearing.
- Live playback is capped at half your device’s sample rate.
Frequently asked questions
What is the difference between the four waveforms?
Why can I not hear very low or very high tones?
Is it safe to play loud tones?
Can I change the frequency while it plays?
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