Online Tone Generator — Free Frequency Generator (20 Hz–20 kHz)

Quick answer

A tone generator plays a precise test tone at a chosen frequency (20 Hz–20 kHz). Use it to test speakers and headphones, check your hearing range, isolate left/right channels, or find the standard 440 Hz reference pitch — free in your browser, nothing recorded.

440 Hz

Waveform Channel Volume

Pure test tones are generated locally in your browser. Start at a low volume — high-frequency and loud tones can be harmful to hearing and to speakers. Nothing is recorded or uploaded.

This free online tone generator plays a clean, precise test tone at any frequency from 20 Hz to 20 kHz, right in your browser. Choose the pitch, waveform, channel and volume — no app, no sign-up, nothing recorded.

What is a tone generator used for?

Testing speakers and headphones — sweep through frequencies to hear rattles, buzzing or a dead range.
Checking your hearing range — most adults stop hearing tones somewhere between 15 kHz and 17 kHz; children can often hear up to 20 kHz.
Left/right channel checks — send the tone to one channel to confirm both sides work.
Cleaning a phone speaker — a low tone around 100–200 Hz helps vibrate trapped water out of the grille (our Phone Speaker Cleaner automates this).
Tuning and reference — 440 Hz is the standard A4 concert-pitch reference.

How to use it

Drag the slider or tap a preset to set the frequency.
Pick a waveform — sine is the purest; square, sawtooth and triangle are richer and louder.
Start at a low volume and press Play tone.
Use the channel selector to send the tone left, right, or to both speakers.

Is it safe?

These are ordinary audio tones, but protect your ears and your gear: start quiet, and avoid sustained high-volume or very high-frequency tones, which can be uncomfortable and can strain small speakers. If a tone sounds painful, turn it down.

Frequently asked questions

What frequency should I use to test my speakers?

Sweep slowly from about 50 Hz upward. Bass drivers handle the low end (below ~250 Hz), mids cover voices, and tweeters handle the highs (above ~2 kHz). Listen for any pitch that rattles, distorts or goes silent.

What is the highest frequency humans can hear?

The typical young-adult range is about 20 Hz to 20 kHz. The upper limit drops with age, so many adults stop hearing tones above 15–17 kHz. This is a rough guide, not a hearing test — for that, try our hearing screening.

Which waveform is loudest?

At the same volume setting, square and sawtooth waves sound louder and harsher than a sine wave because they contain extra harmonics. Use sine for the cleanest single-frequency reference.

Can a tone generator fix my speaker?

A low-frequency tone can help push trapped water out of a speaker grille, which is exactly what our speaker cleaner does. It cannot repair a physically blown or corroded speaker.

Using the Tone Generator for Speaker Testing

When testing speakers, a tone generator is an invaluable tool for identifying issues and ensuring optimal performance. Here’s how to make the most of it:

Start with a frequency sweep: Begin at a low frequency (around 50 Hz) and gradually increase it to the upper limit of human hearing (20 kHz). This helps identify any dead spots or areas where the speaker fails to produce sound.
Listen for distortions: As you sweep through frequencies, pay attention to any rattling, buzzing, or distortion. These can indicate problems with the speaker’s components or enclosure.
Check for consistency: Ensure that the sound remains consistent across both channels. Use the channel selector to send the tone to each speaker individually and verify that both sides are working properly.
Identify frequency response: Note the range of frequencies where the speaker performs best. This can help you understand the speaker’s capabilities and limitations, especially if you’re using it for specific applications like music production or home theater setups.

Symptom	Possible Cause	Suggested Fix
Rattling at low frequencies	Loose components or damaged speaker cone	Check and tighten any loose screws or parts; replace the speaker if the cone is damaged
Dead spot in mid-range	Faulty crossover or damaged mid-range driver	Inspect the crossover components; replace the mid-range driver if necessary
High-frequency distortion	Damaged tweeter or poor-quality audio source	Test with a different audio source; replace the tweeter if the issue persists
Uneven volume between channels	Impedance mismatch or faulty amplifier	Check speaker impedance settings; test with a different amplifier

Common mistakes to avoid

Using excessive volume: Starting at a high volume can damage your speakers and potentially harm your hearing. Always begin with a low volume and gradually increase it as needed.
Ignoring warning signs: If you hear any unusual sounds like crackling, popping, or distortion, stop the test immediately. These can be signs of serious issues that need attention.
Skipping the sweep: Failing to perform a complete frequency sweep can cause you to miss subtle issues that only manifest at certain frequencies.
Not checking both channels: Always verify that both speakers are working correctly by testing each channel individually.
Using the wrong waveform: While square and sawtooth waves can be useful for certain tests, they can also introduce unwanted harmonics that may mask issues. Use a sine wave for the most accurate results.
Assuming the tone generator can fix hardware issues: Remember that while the tone generator can help identify problems, it cannot repair physically damaged speakers or components.