Confirm which side is silent
Use the speaker and headphone test so you are testing with a known signal and not a song that may be mixed to one side.
- Play Left, then Right, at low volume.
- Play Center. It is sent to both sides, so it should be heard in the working ear at least.
- Write down what each ear hears, then compare with the table.
Reading the result
| What you hear | Likely cause |
|---|---|
| Left tone plays, Right tone is silent (or the reverse) | That channel is not reaching the earpiece: plug, cable, balance or a dead driver |
| Both tones play, but only in one ear | A mono plug or adapter, or one earpiece is disconnected |
| Nothing on either tone | This is a no-sound problem. See the no-sound guide |
| The silent side crackles in and out when the cable moves | A broken wire inside the cable |
Wired headphones: plug, jack and adapter
- Push the plug in until it clicks. A plug that is a millimetre short often plays one channel only.
- Look inside the jack with a light. Pocket lint is common in phones. Remove it gently with a wooden toothpick, never metal.
- Check the adapter. Headsets with a microphone use a four-contact plug. Some extension leads, splitters and aeroplane adapters are made for three contacts and drop a channel.
- Try another device. If both ears work there, the first device's jack or settings are at fault. If the same ear is silent, it is the headphones.
Test the cable
Play the Center tone and slowly bend the cable near the plug, then where it enters each earpiece, then at any inline remote. If sound cuts in and out at one spot, a wire has broken there. Headphones with a detachable cable can be fixed with a replacement lead. Fixed cables need a repair or a new pair.
Check balance on Windows and Mac
A balance slider pushed all the way to one side silences the other ear completely.
Windows 11: Settings → System → Sound, click the output device and check that neither the left nor the right channel is at zero.
Mac: System Settings → Sound → Output, select the headphones and centre the Balance slider.
Mono audio does not cause this. It sends the same sound to both ears, so it can hide a channel problem but cannot silence one side.
Wireless earbuds
With true wireless earbuds, each bud connects separately, and one can drop out while the other keeps playing.
- Check the charge of each bud in the maker's app or your phone's Bluetooth screen. One flat bud is the most common cause.
- Clean the charging contacts on the silent bud and in the case with a dry cotton bud. A bud that is not charging will not switch on.
- Put both buds in the case, close the lid for 30 seconds and take them out together.
- If one is still silent, remove the earbuds from your device's Bluetooth list, reset them as the instructions describe and pair them again.
When to stop troubleshooting
If one side is silent on every device, with the balance centred and a known-good cable, the driver in that earpiece has failed. That is a repair or warranty matter and no setting will bring it back.
Further reference: Official device or browser documentation ↗
Reviewed October 2026 · How we write our guides · Suggest a correction