Microphone Only in the Left Channel

The Short Answer

Your microphone is mono, but it's being treated as one side of a stereo pair. Audio interfaces and mixers call input 1 "left" and input 2 "right", so a single mic on input 1 lands in the left channel and the right stays silent.

The fix depends on where you hear the problem:

Fix It Live: Stop It Happening Next Time

OBS Studio: open Edit → Advanced Audio Properties and tick Downmix to Mono on the row for your microphone. The OBS audio mixer guide describes this as the way to send a single-channel source to both channels. Do a short test recording and check the level, since downmixing can make it a little quieter.

Audacity: the Audacity recording FAQ recommends recording in stereo, then choosing Split Stereo to Mono from the track's dropdown menu and closing the silent track with its X button. The remaining mono track plays out of both speakers. Avoid Tracks → Mix → Mix Stereo Down to Mono for this, because it averages the channels.

Audio interface (Focusrite, Behringer and similar): plug the mic into input 1, then set the track or input in your recording app to mono, input 1. Most recording and music apps have a mono option per track.

Windows: Windows has no general switch to turn a stereo input into mono. Some audio drivers offer a 1-channel format in the microphone's properties; if yours does, choosing it fixes every app at once. Otherwise set mono in the app you record with.

Other apps: look for a mono or channel setting on the microphone input. Menu names differ between apps and versions, so if you can't find one, record as usual and fix the file afterwards.

Only You Hear It in One Ear?

If you hear yourself on one side while monitoring, but recordings and other people sound fine, the problem is playback, not the microphone. Your computer can play everything in mono so both ears get the same sound:

• Windows 11: Settings → System → Sound, then turn on Mono audio.
• Mac: System Settings → Accessibility → Audio, then turn on Play stereo audio as mono.

This changes only what you hear. It doesn't change what's recorded or what others receive, so if a recording is one-sided, fix the source as above.

Fix a Recording You Already Have

1. Open the Audio Channel Fixer and choose the file (MP3, WAV or M4A).
2. Read the meters. For a typical one-sided recording the tool reports something like Left −9.0 dB, Right silent and says “Right channel is silent”.
3. Leave Copy left to both ears selected (it is chosen for you) and click Fix channels.
4. Play the preview on headphones, then download the WAV, or the MP3 for a smaller file.

If the voice is on the right instead, the tool selects Copy right to both ears. Working with a video? Extract the audio first; the fixer only takes audio files.

Copy, Don't Mix

“Convert to mono” sounds like the obvious fix, but many mono conversions, including Audacity's, average the two sides. When one side is silent, the average is half the signal. We checked this with the fixer on a test tone: mixing gave exactly half the level of copying, which is about 6 dB quieter.

Audacity's FAQ warns about the same “half-volume mono recording”. Mixing is the right choice only when both sides hold something useful, such as two microphones.

Things That Trip People Up

• It sounds fine on speakers. Laptop and phone speakers are close together, so a one-sided recording can go unnoticed until someone listens on headphones.
• Headphones vs file. If all audio plays on one side, the problem is your headphones or a balance setting, not the recording.
• Both sides quiet. If the fixer reports both channels as quiet, the problem is level rather than channels. See why a recording is too quiet.
• Reversed stereo. If left and right are simply the wrong way round, use Swap left and right instead.