Stereo / left-right speaker test
Confirm your speakers or earbuds work and aren't wired backwards. Play a tone through the left channel, the right channel, or both, using the Web Audio API — entirely in your browser, with nothing sent to a server.
Tip: use headphones, or check your speaker balance — the L indicator should sound on your left.
100% local — nothing leaves your device
How to use it
- 1 Put on your headphones or sit centred between your speakers.
- 2 Press “Left” — you should hear sound only on the left. Then press “Right”.
- 3 Press “Both” to check balance, or “Sweep” to alternate left and right.
- 4 Adjust the frequency and volume if you want a higher or quieter tone.
Troubleshooting
Left and right sound swapped
If “Left” plays on your right side, your channels are reversed. Check that earbuds are in the correct ears, that a 3.5mm plug is fully inserted, and your OS balance slider is centred. For external speakers, swap the L/R cables at the back to correct the wiring.
No sound on one side
First test the other side here to confirm which channel is silent. Then check the OS balance isn't pushed fully one way, the plug is seated, and the cable isn't damaged. Try another pair of headphones to tell whether the fault is the audio device or the output jack.
Stereo test not working in Chrome or Safari
Browsers require a click before they can play audio, so press a channel button to start. If it stays silent, make sure the tab isn't muted (right-click the tab), the site has sound permission, and your system output device is the speakers or headphones you expect.
Frequently asked questions
Is any audio recorded or uploaded?
No. The tones are generated locally with the Web Audio API. Nothing is recorded, and nothing is sent to any server.
Why should I use headphones?
Headphones isolate each ear so you can clearly tell left from right. With speakers placed close together, both ears hear both channels, making a swap harder to notice.
Does it work on a phone?
Yes. Plug in or pair your headphones and tap the channel buttons. A single phone speaker is mono, so use headphones or external speakers to test true stereo.
What frequency should I use?
Any tone works for a left/right check. A mid frequency like 440 Hz is easy to hear; lower tones test bass response and higher tones reveal whether one side sounds muffled.