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 press Share result for a link. It holds each tone’s frequency, waveform, channel, level and on/off switch plus the A4 reference (or the sweep’s range, length, scale, waveform, channel and repeat), never the volume. Whoever opens it can play the sound and open it in the generator.
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.