ONLINE SOUND TESTSupport this project Diagnose

One Headphone or Speaker Side Not Working

Only the left or only the right test signal is audible.

Fast isolation checks● Do these in order
  1. 01

    Run the directional test twice at a moderate level.

  2. 02

    Reconnect every plug fully and remove unnecessary adapters.

  3. 03

    Try the same device on another source, then a known-good device on this source.

Run guided diagnosis Open the matching test

Most useful causes to check

Balance control

An accessibility or device balance slider may be set to one side.

Connection

A partially inserted plug, damaged cable, dirty contact or incorrect interface routing can interrupt one channel.

Driver or speaker fault

If the fault follows the device across sources, the physical transducer or internal connection may need service.

Repair steps by system

Interfaces change between system versions. Use the setting names as landmarks, then return to the same test.

Windows

  1. Open Settings → System → Sound and verify input and output devices.
  2. Open Volume mixer and confirm the browser is not muted or routed elsewhere.
  3. Disable enhancements temporarily and retest.

macOS

  1. Open System Settings → Sound and verify the selected output.
  2. Check output volume and the left/right balance control.
  3. Reconnect the device, then quit and reopen the browser if routing is stale.

iPhone and iPad

  1. Open Control Center and check the current AirPlay output.
  2. Open Settings → Accessibility → Audio & Visual and review mono audio and balance.
  3. Disconnect and reconnect wired or Bluetooth audio.

Android

  1. Use the media output switcher to choose the intended device.
  2. Check media volume separately from ring and alarm volume.
  3. Review Accessibility audio balance and mono settings, then reconnect the device.

Verify the repair

Change one setting or connection, then repeat the same controlled signal. If the symptom follows the hardware to another source, physical service becomes more likely.

Retest now →

Read the matching field guides

01System checks · 7 minHow to Check Left and Right Audio Balance in Windows 11Check Windows 11 left and right channel identity and balance, then separate a settings offset from a cable, fit, room, or driver problem.02Audio basics · 5 minMono vs Stereo Audio: How to Check Which Mode Is ActiveLearn what mono and stereo change, then use separated channel signals to find system mono settings, reversed wiring, or content that is mono by design.