Online tone generator

How to use the tone generator

1. Type a frequency in Hz (for example 440) or drag the slider. Quick buttons jump to common values from 20 Hz to 20 kHz.
2. Choose a waveform: sine is a pure tone, square, sawtooth and triangle add harmonics and sound brighter.
3. Choose Left, Both or Right to send the tone to one speaker or ear only.
4. Press Play tone. You can change the frequency while it plays. Start with the volume low, then raise it slowly.

The sound is generated in your browser with the Web Audio API. Nothing is uploaded and no microphone is used.

Useful test frequencies

• 440 Hz: concert pitch A4, the standard tuning reference for instruments.
• 20–60 Hz: sub-bass. Good for checking a subwoofer; small speakers and laptops will be silent here.
• 100–250 Hz: bass and low male voice range.
• 1000 Hz (1 kHz): the classic reference tone for levels and speaker checks.
• 2–5 kHz: the range where human hearing is most sensitive.
• 8–12 kHz: treble and cymbals. A tone that is audible but harsh is a sign of speaker resonance.
• 15–20 kHz: the top of hearing. Most adults cannot hear above 16–17 kHz, and this is normal, especially with age.

What people use a tone generator for

• Speaker and headphone testing: find dead drivers, rattles and the lowest frequency your speakers can play.
• Subwoofer checks and room modes: step through 30–120 Hz and listen for frequencies that boom or vanish.
• Tuning: use 440 Hz (A4) as a reference for an instrument.
• Hearing range check: sweep upward and note where the tone disappears. This is a rough check, not a medical hearing test.
• Left / right channel test: send the tone to one side only to confirm the wiring.

Frequently asked questions

What frequencies can this tone generator play?

From 20 Hz to 20,000 Hz (20 kHz), the normal range of human hearing. Whether you can hear the extremes depends on your speakers and your ears.

Which waveform should I choose?

Use sine for a pure single frequency. Square, sawtooth and triangle waves contain extra harmonics, so they are louder and brighter at the same setting.

Why can't I hear very low frequencies?

Phone, laptop and small speakers cannot reproduce much below 80–100 Hz. Try headphones or a speaker with a subwoofer.

Is it safe for my speakers and ears?

Keep the volume low, especially with square waves and high frequencies. Never play a loud tone through headphones.

Want a guided check instead? Use the speaker test or the headphone test.