Bass Test
Play low tones from 20 to 250 Hz to hear how deep your speakers, subwoofer or headphones go.
Online Tone Generator
Play a tone at any frequency from 20 Hz to 20 kHz, as a sine or triangle wave, on the left, right or both sides. Sweep the range to hear where your speakers or headphones fade or rattle.
Lower your volume before starting, especially with headphones. Nothing plays until you press a button.
440 Hz
Above about 16 kHz, many speakers and many adult listeners reach their limit. That is normal.
Presets
Waveform
Channel
Stopped
Runs entirely in your browser. Test results, audio and video never leave your device.
How to play a test tone
- Turn your system volume down first. Tones in the middle of the range sound far louder than deep bass at the same setting.
- Set a frequency with the Frequency slider, type a whole number in Exact value (Hz) and press Enter, or press a preset.
- Choose Sine or Triangle and Left, Both or Right, then press Play. You can change the frequency, waveform and side while the tone plays.
- Press Sweep 20 Hz to 20 kHz to hear the whole range in 20 seconds, and press Stop where the sound changes.
- Press Play to hear the frequency the sweep reached as a steady tone, then fine-tune it with the slider.
What is a tone generator?
A tone generator plays a steady tone at a frequency you choose, most often a sine wave: a pure tone with no overtones. It is used to hear which frequencies speakers and headphones reproduce, to find rattles, and to provide reference tones such as 440 Hz for tuning or 1 kHz for setting levels.
Common test tones and what they are for
| Frequency | What it is | Use it to |
|---|---|---|
| 20 to 60 Hz | Sub-bass, felt as much as heard | Check how deep a subwoofer or headphones go with the Bass Test |
| 100 Hz | Low bass; most laptop and phone speakers play very little below it | See whether a small speaker has any bass |
| 440 Hz | Concert pitch: the A above middle C | Tune an instrument by ear |
| 1 kHz | The usual reference tone in audio | Set or compare levels, and check that a channel works |
| 10 to 20 kHz | Upper treble, the top of the range | Check tweeters and earbuds with the Treble Test |
What a frequency sweep shows
A sweep glides from 20 Hz to 20 kHz so you hear the whole range in one pass. It rises exponentially, about 2 seconds per octave, because each doubling of frequency sounds like the same step in pitch.
Listen for where a small speaker’s bass begins, where the top end fades out, or where something buzzes; the Audio Distortion Test has a slower sweep and level steps for that. The sweep keeps moving while you react, so after pressing Stop, play the frequency it reached and adjust it with the slider. After a full sweep the frequency is left at 20 kHz, so pick another before you press Play.
What you can check with a test tone
- The lowest and highest tones your speakers or headphones play audibly.
- Rattles, buzzing or distortion that appear only at certain frequencies.
- A difference between the left and right sides at the same frequency, using Left and Right.
- Frequencies where the sound suddenly gets louder or quieter, from the speaker or the room.
How it works
The page generates the tone live in your browser with the Web Audio API; nothing is recorded or measured. The Frequency slider is logarithmic, with 1,000 steps from 20 Hz to 20 kHz, so every octave gets the same length of travel.
Frequency changes glide over a few milliseconds and each tone fades in and out over 15 ms, so there are no clicks. The sweep follows an exponential ramp over 20 seconds. Even at the top of the Volume slider, the page’s signal peaks about 9 dB below digital full scale in each channel.
Limitations
- This is not a hearing test: the level that reaches your ears depends on your equipment and volume, which the page cannot know. For a hearing check, see an audiologist or a doctor.
- The page cannot hear what your speakers produce, so it cannot draw a frequency response or give a sound level.
- Speakers, headphones, Bluetooth links and audio enhancements can soften or cut tones before they reach you, especially near 20 Hz and 20 kHz.
- Playback stops when the tab is hidden, for example when you switch tabs or minimize the window.
- Keep the volume moderate. Loud tones can damage hearing and small speakers.
Frequently asked questions
Can I play a tone in only one ear or one speaker?
Yes. Choose Left or Right to play the tone or the sweep on one side only, or Both for both sides; you can switch while it plays. To check quickly that left and right are not swapped, use the Speaker Test or the Headphone Test.
What is the difference between a sine and a triangle wave?
A sine wave is a pure tone at a single frequency. A triangle wave sounds slightly brighter because it adds fainter overtones at odd multiples of the frequency: 3, 5, 7 times and so on. Use Sine to judge whether a speaker plays a frequency, because the overtones can be audible when the tone itself is not.
Why do some frequencies sound louder than others?
Because ears are not equally sensitive across the range. Hearing is most sensitive around 2 to 5 kHz and much less sensitive to deep bass and the highest treble, and speakers and rooms add peaks and dips of their own. The same Volume setting can sound quiet at 50 Hz and loud at 3 kHz.
Can I download the tone as an MP3 or WAV file?
No. The page generates the tone live in your browser and has no way to save it as a file. Keep the page open and press Play whenever you need the tone.
Can it play below 20 Hz or above 20 kHz?
No. The generator covers 20 Hz to 20 kHz, the standard audio band. Browsers usually output audio at 44.1 or 48 kHz, which cannot carry tones above 22.05 or 24 kHz, and many speakers and headphones roll off well before either end.