Loona Tone Generator - Free Online Test Tone Generator
Testing whether a subwoofer really reaches down low, checking if a tweeter still works, tuning an instrument to A440, or finding the highest pitch you can still hear - set the frequency and waveform, press play, and the tone is generated live in your browser.
How to generate a test tone
- Choose a waveform - sine is the pure reference tone; square, triangle and sawtooth add harmonics and sound progressively brighter.
- Set the frequency with the slider, the quick-pick buttons, or type an exact value from 20 Hz to 20,000 Hz.
- Set the duration (1-30 seconds) and a modest volume - high-pitched tones can be uncomfortable, so start low.
- Press "Play Tone" to hear it, or "Download Tone as WAV" to save a stereo WAV file of the tone.
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Frequently Asked Questions
Is the Tone Generator free?
Yes. It is completely free with no sign-up and no watermark.
Is anything uploaded to a server?
No. The tone is synthesized live inside your browser with the Web Audio API. The WAV download is also created on your device.
What frequencies can it generate?
From 20 Hz to 20,000 Hz - the standard range of human hearing. Whether you actually hear the extremes depends on your speakers or headphones and your own ears: small phone speakers cannot reproduce 20 Hz, and most adults stop hearing somewhere between 14 and 17 kHz.
What is the difference between the waveforms?
Sine is a single pure frequency. Triangle is a softer tone with faint harmonics, square is hollow and buzzy with strong odd harmonics, and sawtooth is the brightest, containing every harmonic. Speaker tests are normally done with sine tones.
Why does 440 Hz matter?
440 Hz is the musical note A4, the international standard pitch that orchestras tune to. If you play it next to an instrument playing A, you can tune the instrument until the two match.
How it works
The tone is synthesized mathematically inside your browser with the Web Audio API - an oscillator produces the exact waveform you chose at the exact frequency you set. The download renders the same waveform sample by sample into a standard WAV file, so the file you save matches what you heard.
Worked example
You bought a small subwoofer rated down to 40 Hz and want to check it honestly. You set a sine tone at 50 Hz, then 40 Hz, then 30 Hz, playing each for a few seconds. The 50 and 40 Hz tones are clearly felt, the 30 Hz tone is silent on this speaker - so its real-world limit in your room is around 40 Hz, exactly as rated.
One safety note: test tones - especially high frequencies and square waves - can be much more piercing than music at the same volume setting. Always start with the volume low and raise it slowly.
More questions
Can I test my hearing with this?
You can explore your hearing range for fun by slowly raising the frequency until the tone disappears - but keep the volume low, and remember this is not a medical test. A proper hearing check needs calibrated equipment.
Why is the downloaded WAV in stereo?
The download contains the same tone on both channels, so it plays identically in both ears and works as a test file in any player or editor.
The tone sounds crackly at very low volume steps - is that normal?
Square and sawtooth tones are naturally harsh because of their harmonics. For smooth reference testing, use the sine waveform.
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