🔊 Frequency/Tone Generator
Generate pure tones from 20Hz to 20kHz. Includes Water Extraction Mode for clearing speakers of water. Free, no signup.
Plays a low-frequency tone (~165 Hz) with periodic volume modulation to help eject water from phone/watch speakers.
📋 When to Use the Frequency Generator & Tone Tool
It's most useful for checking audio gear. Sweep through the frequencies to hear where a speaker or subwoofer starts to rattle, distort, or drop out; play a steady tone in each ear to confirm your headphones' left and right channels are wired correctly; or feed a known tone into a mixer or interface to check the signal path. Musicians can use a preset like A4 (440 Hz) as a tuning reference, and you can run a rough check of your own hearing range by slowly raising the frequency until the tone fades out.
A couple of honest limits. This is a convenience tool, not test equipment or a medical device — your real-world results depend heavily on your speakers, headphones, sound card, and room, none of which are calibrated. For a genuine hearing assessment, see an audiologist; for precise acoustic measurement, use a proper signal generator and calibrated microphone.
⚙️ How the Frequency Generator & Tone Tool Works
Sound is vibrating air, and frequency — measured in hertz (Hz) — is how many times per second that vibration repeats. A low 50 Hz tone is a slow rumble; a high 10,000 Hz tone is a thin whistle. This tool uses the Web Audio API's OscillatorNode to generate a mathematically pure tone at whatever frequency you set, computed in real time by your browser and sent straight to your audio output — nothing is recorded or uploaded.
The waveform buttons change the tone's character at the same pitch. A sine wave is the purest possible tone, a single frequency with no overtones — ideal for clean testing. Square, sawtooth, and triangle waves add increasingly rich harmonics (mathematical multiples of the base frequency), which is why they sound brighter or harsher even though the fundamental pitch is identical. Square and sawtooth are the buzziest; triangle sits between them and sine.
The note label below the frequency is calculated from the pitch using equal-temperament tuning, where A4 = 440 Hz and every octave doubles the frequency (A5 = 880 Hz, A3 = 220 Hz). The water-ejection mode is a separate trick: it drops to a low ~165 Hz tone and pulses the volume up and down, and the resulting vibration can help shake water droplets out of a phone or watch speaker grille — the same idea behind the feature some smartwatches ship with.
How to Use the Tone Generator
- Select a waveform — Choose Sine (smooth), Square (harsh), Sawtooth (bright), or Triangle (mellow). Each sounds distinct.
- Set your frequency — Drag the slider from 20Hz to 20kHz, or click a preset (C4, A4, 1kHz, 5kHz, 10kHz). Use the fine-tune buttons for precise adjustments.
- Adjust volume — Set the output level between 0-100%. Start low to protect your ears and speakers.
- Try Water Extraction Mode — Toggle the special mode to play a low-frequency modulated tone (~165 Hz) designed to help eject water from phone or watch speakers.
Frequently Asked Questions
What's the difference between the waveforms?
They share the same pitch but differ in tone color. A sine wave is the purest — one frequency, no overtones — and is the cleanest choice for testing. Square, sawtooth, and triangle waves add harmonics on top of the fundamental, so they sound progressively brighter or buzzier. Square and sawtooth are the harshest; triangle is gentler, sitting between sine and the rest.
Can I really test my hearing with this?
You can get a rough idea, not a diagnosis. Slowly raise the frequency at a comfortable volume and note where the tone fades out. Many people stop hearing somewhere between 15 and 18 kHz, and the upper limit tends to fall with age — but your result also depends on your headphones, your volume, and background noise, so it isn't a substitute for a real hearing test. If you're worried about your hearing, see an audiologist.
Is it safe for my ears?
Treat it with care. Sustained loud sound damages hearing, and pure high-frequency tones can be deceptively loud — especially through headphones, where the sound is right against your ear. Start with the volume low, keep sessions short, and never crank an inaudible high frequency up "to check if it's working," since you could be playing it far louder than you realize.
Is it safe for my speakers?
At sensible volumes, yes. The risk is loud, very low bass on small drivers — a phone or laptop speaker pushed hard at sub-50 Hz can distort or even be damaged, because tiny drivers can't move enough air to reproduce it. Keep low frequencies quiet, and back off immediately if you hear buzzing or rattling rather than a clean tone.
What is the water-ejection mode?
It plays a low ~165 Hz tone and pulses the volume, and that vibration can help shake water out of a phone or watch speaker grille after it's been splashed or submerged. It's the same principle some smartwatches use. It often helps but isn't guaranteed — and it's for clearing speakers only, nothing to do with hearing or any medical use.
Why can't I hear very low or very high tones?
Two reasons. Human hearing tops out around 20 Hz to 20 kHz, and the extremes get harder to hear with age. On top of that, most speakers can't physically reproduce the far ends — small phone speakers often roll off below ~200 Hz and above ~15 kHz — so silence at the extremes may be your hardware, not your ears.