Left / Right Audio Test
Confirm your left and right channels play from the correct side. Play a clean tone in each ear to check for a swapped, silent or unbalanced stereo channel.
Put your headphones on the right way round (look for the L and R marks). Play each channel and confirm the sound comes from the matching ear.
How the left/right test works
- Put your headphones on the right way round — look for the L and R marks on the earcups.
- Press Left: a 440 Hz tone should play only in your left ear.
- Press Right: the tone should move to your right ear only.
- Press Both: it should sound centred, equally in both ears.
The tone is panned in software using the Web Audio stereo panner, so it is a true channel test, not just a volume change.
Reading the results
- Left plays on the right (or vice versa): your channels are swapped — the headset is on backwards, or an adapter/soundcard has reversed the wiring.
- One side is silent: a broken driver, a damaged cable near the plug, or the OS balance slider pushed fully to one side.
- "Both" leans to one side: your balance is off-centre; reset it in your sound settings.
Fixing a swapped or unbalanced channel
First, reset the balance: on Windows go to Settings → System → Sound → your device → Volume and make sure the left/right balance is centred; on macOS use System Settings → Sound → Output and centre the balance slider. If the tone is still on the wrong side with the headset worn correctly, the reversal is in the hardware or an adapter. A single silent channel that persists across devices usually means a cable break — flex the cable near the plug while a tone plays to confirm.
Speakers too
This test works for desktop speakers as well: label your left and right speakers, play each channel, and confirm the correct one responds — a quick way to catch crossed speaker cables. For a fuller check, see testing stereo speakers and fixing speaker balance.
Frequently Asked Questions
What does the left/right audio test do?
It plays a clean tone panned fully to the left channel, fully to the right, or centred in both, so you can confirm each side plays from the correct ear and that stereo is working.
My left and right are swapped — how do I fix it?
First make sure the headset is worn correctly (L on the left). If the tone is still reversed, an adapter, soundcard or the headset wiring has crossed the channels. Try a different port or cable, or swap the channels in your audio software.
Only one side plays — what's wrong?
Check the balance slider in your OS sound settings, which may be pushed fully to one side. If it is centred and one side is still silent, the cable is likely broken near the plug or the driver has failed — test on another device to confirm.
Does this work for speakers as well as headphones?
Yes. Label your left and right speakers, play each channel, and confirm the correct speaker responds. It is a fast way to catch crossed speaker cables.
Is the tone a real channel test or just volume?
It is a real channel test. The tone is panned in software with the Web Audio stereo panner, so the left button sends audio only to the left channel, not just a quieter mix.
Why use a tone instead of music?
A steady tone makes it obvious which ear is producing sound and removes the stereo mixing in music that can make a swapped or silent channel hard to notice.