How to use the tone generator
This online tone generator creates a continuous sound at any frequency between 1 Hz and 20,000 Hz. It is useful for testing speakers and headphones, tuning instruments, science experiments, finding rattles and checking your hearing range.
- Pick a frequency. Drag the slider, type an exact value in the box, or press one of the presets.
- Choose a waveform (sine, square, triangle or sawtooth) and an output channel (both, left or right).
- Press Play. You can move the slider while the tone is playing, and it will glide smoothly to the new frequency.
- Fine-tune with the ±1 Hz buttons, or jump a full octave up or down.
Tip: you can link straight to a frequency by adding ?f= to the address, for example speakersoundtest.com/tone-generator/?f=1000.
Waveforms explained
| Waveform | Sound | Best for |
|---|---|---|
| Sine | Pure, smooth tone with only one frequency | Speaker and hearing tests, tuning, measurements |
| Square | Buzzy and hollow, rich in odd harmonics | Retro game sounds, testing distortion |
| Triangle | Softer than square, flute-like | Gentle test tones, synth sounds |
| Sawtooth | Bright and harsh, contains all harmonics | Synth sounds, finding resonances |
For most tests, use a sine wave. The other waveforms contain extra frequencies (harmonics) above the main one, so you may still hear a square or sawtooth wave even when the base frequency is too low for your speaker.
Useful frequencies
| Frequency | What it is |
|---|---|
| 20 Hz | Lower limit of human hearing |
| 50 / 60 Hz | Electrical mains hum (50 Hz in Europe, Asia and Africa, 60 Hz in North America) |
| 82.41 Hz | Low E string of a guitar |
| 261.63 Hz | Middle C on the piano |
| 440 Hz | A4 – the standard tuning reference for instruments |
| 1,000 Hz | Standard reference tone used in audio equipment and broadcasting |
| 2,000–5,000 Hz | The range where human hearing is most sensitive |
| 17,400 Hz | The so-called "mosquito tone", hard for most adults to hear |
| 20,000 Hz | Upper limit of hearing for young people |
What can you do with a tone generator?
Test speakers and headphones
Step through low, mid and high frequencies to hear where your speakers start and stop working. For quicker checks, use the dedicated speaker test, headphone test or bass test.
Tune instruments
Play 440 Hz (A4) and tune your instrument until the beating between the two sounds disappears. Use the octave buttons to find the same note in a lower or higher register.
Find rattles and resonances
Slowly move the slider through the bass range. When something in the room or car starts buzzing, stop and fine-tune with the ±1 Hz buttons to find the exact frequency that causes it.
Science and education
Teachers use tone generators to demonstrate pitch, frequency and wavelength, sound waves in water or sand (Chladni patterns), and the limits of human hearing.
Check your upper hearing limit
Start at 10,000 Hz and move up slowly with low volume. The point where the tone vanishes is roughly your upper limit with that device. Results depend on your speakers or headphones, so this is not a medical test.
Frequently asked questions
What is the range of this tone generator?
You can generate any frequency from 1 Hz to 20,000 Hz, with decimal precision below 100 Hz.
Why can't I hear very low or very high frequencies?
Your speakers or headphones may not be able to reproduce them, and human hearing is less sensitive at the edges of the range. Below about 20 Hz and above about 15–20 kHz many people hear nothing at all.
Can I play the tone in only one ear?
Yes. Set the Output option to Left or Right.
Can I use this tone generator on my phone?
Yes. It works in Safari, Chrome and other modern mobile browsers. Keep the screen on while the tone is playing, as some phones pause audio when the screen locks.
Is 432 Hz better than 440 Hz?
440 Hz is the international tuning standard. Some musicians prefer 432 Hz for its sound, but there is no scientific evidence that it has special effects. Both are available here so you can compare.