Tone generator — pure tone & signal generator online

What is a tone generator?

A tone generator (also called a signal generator or audio tone generator) produces a steady audio tone at a frequency you choose, so you can test speakers, check hearing range, tune instruments, or diagnose audio problems. This online tone generator uses the Web Audio API to synthesize a pure sine wave or a square, triangle, or sawtooth tone from 20 Hz to 20 kHz, with fine frequency stepping and a volume control. Unlike recorded test files, a browser tone generator produces the tone locally and instantly — you can sweep frequencies, compare waveforms, and find exactly the pitch you need without installing anything. Nothing is recorded or uploaded; the sound never leaves your device.

Online tone generator features

A precise, fully local audio tone generator built on Web Audio for speaker testing, hearing checks, and audio work.

1. Pure sine tone from 20 Hz to 20 kHz: Generate a clean sine wave across the full audible range. Sine tones are the standard for speaker testing and hearing checks because they contain a single frequency.
2. Square, triangle & sawtooth waveforms: Switch between sine, square, triangle, and sawtooth to compare how different waveforms sound — square and sawtooth add harmonics useful for testing and synthesis.
3. Fine frequency control: Adjust frequency with a slider plus fine +/- buttons, or jump to common presets like A4 (440 Hz) or the standard test tones. The current frequency and nearest note are shown live.
4. Independent volume & mute: Set a comfortable output level with the volume slider and mute instantly. Frequencies near the top of your hearing range can be piercing, so level control matters.
5. Frequency sweep presets: Quick presets cover bass, mid, and treble regions plus standard tuning references, making it easy to check a speaker across its range or find a specific test tone.
6. Local Web Audio, no upload: Tones are synthesized in your browser with the Web Audio API. No audio is recorded, streamed, or sent to a server — this is a purely local tone generator.

How to use an online tone generator

A few simple steps to generate the exact test tone you need with this free online signal generator.

1. Choose a waveform: Start with sine for a pure tone. Switch to square, triangle, or sawtooth if you want a richer, brighter sound with harmonics.
2. Set the frequency: Drag the frequency slider or use the presets and fine-tune buttons to land on the exact pitch you need, from 20 Hz bass to 20 kHz treble.
3. Adjust volume before playing: Set the volume slider low first, then press play and raise it to a comfortable level. High frequencies and square waves can be surprisingly loud.
4. Listen and compare: Use the tone to test a speaker driver, check your hearing at a frequency, or tune by ear. Press stop when you are done — the generator produces no sound when idle.

Tone generator tips & audio troubleshooting

How to get useful results from this signal generator and what to do if you hear nothing.

1. Play a 440 Hz A for instrument tuning: Set the generator to 440 Hz (A4) with a sine waveform to use as a tuning reference for instruments that tune to standard pitch. Many musicians also use 432 Hz for an alternative reference.
2. Use low tones to test bass drivers: A 50–100 Hz sine is a good check for a subwoofer or bass driver: if you feel the air move or hear a clean low tone, the driver is working. Distortion at low volume may indicate a damaged cone.
3. Sweep to find hearing or speaker dropouts: Slowly sweep from low to high frequency. Quiet gaps or crackling at specific frequencies can reveal a speaker issue, while a consistent audible range roughly maps your own hearing.
4. Why do I hear nothing when I press play?: Check that your device volume is up and not muted, and that the correct output device is selected. Browser autoplay policies require the page to be open and interacting — press play again if needed.
5. High frequencies can be uncomfortable: Frequencies above 12 kHz are piercing for many people and inaudible to others. Keep the volume low and avoid long exposure to loud high tones to protect your hearing.
6. Square and sawtooth are louder than sine: Harmonic-rich waveforms sound louder at the same volume setting. Lower the volume when switching from sine to square or sawtooth to avoid a sudden jump in loudness.

Sources & References

Authoritative references for the Web Audio APIs used to synthesize tones and control volume in this tone generator.

• OscillatorNode — generating the tone

  “The OscillatorNode interface represents a periodic waveform, such as a sine wave. It is an AudioScheduledSourceNode audio-processing module that causes a specified frequency of a given waveform to be created.”

  This tone generator drives an OscillatorNode whose type (sine, square, triangle, sawtooth) and frequency you control. MDN documents how the node produces a continuous periodic tone at the configured frequency. developer.mozilla.org/en-US/docs/Web/API/OscillatorNode

• GainNode — controlling output volume

  “The GainNode interface represents a change in volume of a signal. It is an AudioNode audio-processing module that causes a given gain to be applied to the input data.”

  The volume slider sets the gain of a GainNode between the oscillator and your speakers, letting you keep even loud waveforms at a comfortable level. developer.mozilla.org/en-US/docs/Web/API/GainNode

Frequently Asked Questions

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