How to use the tone generator
- Type a frequency in hertz, drag the slider, or enter a musical note such as A4 or C#5.
- Press Play (or Space). The tone fades in over a third of a second so it never starts with a jolt. Start with the volume low.
- Fine-tune with the ±1 and ±0.1 Hz buttons or the arrow keys, pick a waveform, and send the tone to the left, right or both channels.
- Add up to three tones at once, or switch to Sweep to glide between two frequencies.
- Download exactly what you hear as a WAV file, or copy a link that reopens these settings.
Waveforms explained
- Sine is a pure tone with a single frequency and no harmonics. Use it for hearing checks, speaker testing and tuning.
- Square contains only odd harmonics (3×, 5×, 7×…) and sounds hollow and buzzy, like an old video game.
- Sawtooth contains every harmonic and sounds bright and brassy. It is the classic starting point for synthesizer sounds.
- Triangle has odd harmonics that fade quickly, so it sounds between a sine and a square: soft, like a flute.
The generator uses band-limited waveforms, so square and sawtooth tones do not produce the harsh aliasing that naive digital oscillators create at high frequencies.
What people use it for
- Testing speakers and headphones. Sweep from 20 Hz to 20 kHz to find where your speakers roll off or rattle. The speaker test adds a left/right and phase check.
- Checking your hearing range. Most adults stop hearing somewhere between 14 and 17 kHz. For a guided version with a result by age, try the hearing test.
- Tuning instruments. Set A4 to 440 Hz (or 432 Hz) and tune by ear until the beating disappears. Two close tones, such as 440 and 442 Hz, demonstrate the beat you listen for.
- Tinnitus matching. Many people with tinnitus use a tone generator to find the pitch of their ringing, to describe it to a doctor. Keep the volume low.
- Physics and electronics. Demonstrate beats, standing waves, or resonance; drive a speaker to show Chladni patterns; or produce a clean reference signal for an oscilloscope or audio interface.
Tips and troubleshooting
- Very low and very high tones may be silent. Laptop and phone speakers rarely reproduce anything below about 150 Hz, and few adults hear above 17 kHz. That is your equipment or your ears, not the generator. The oscilloscope shows the signal is there.
- Play several tones without clipping. When their combined level would go over full scale, the generator turns them down together (you will see a note under the tones), so the output never distorts.
- Exported WAV files are normalized to the peak level you choose (−3 dBFS by default) and use the settings shown, including sweeps and channel routing. 60 seconds of 48 kHz 16-bit stereo is about 11 MB.
- No sound? Check that the right output device is selected, the tab isn’t muted, and on iPhone that silent mode is off.
- Protect your ears. Pure tones are more tiring than music. Keep the level moderate and take breaks, especially with headphones.
Frequently asked questions
How do I play a specific frequency?
Type the frequency in hertz into the big box (decimals like 432.5 are fine) and press Play or the Space bar. You can also drag the slider, use the ±1 and ±0.1 Hz buttons, or type a note such as A4 or C#5.
What is the range of this tone generator?
1 Hz to 22,000 Hz, adjustable in steps as small as 0.001 Hz. Most speakers cannot reproduce the extremes, and most adults do not hear above about 17 kHz, so the oscilloscope is there to show the tone is playing even when you cannot hear it.
Can I play more than one tone at once?
Yes. Add up to three tones, each with its own frequency, waveform, level and left/right channel. That lets you hear beats (440 and 442 Hz), chords, the US dial tone (350 + 440 Hz) or binaural beats with a different tone in each ear.
How do I download a tone as a WAV file?
Open Download as WAV, choose a length, sample rate, bit depth, peak level and stereo or mono, then press Download WAV. The file is rendered in your browser from exactly the settings you hear, including sweeps and channel routing.
What is the difference between 440 Hz and 432 Hz tuning?
They are two choices for the pitch of A4. 440 Hz is the international standard; 432 Hz is slightly lower and popular with some musicians. Switching the reference retunes any tone that sits on a note, so A4 moves from 440 to 432 Hz.
What does a frequency sweep do?
It glides smoothly from a start to an end frequency over the time you choose, on a logarithmic scale (equal time per octave, best for audio testing) or a linear one. Use it to find speaker resonances and rattles or the limits of your hearing.
Is it safe to listen to test tones?
At a moderate volume, yes. Start low, because pure tones sound louder and are more tiring than music, and very high or low tones at high volume can damage hearing and small speakers. The generator always fades in to avoid sudden loud starts.