Audio that plays only in your left ear is almost always a channel-assignment problem, not a broken microphone. OBS treats a stereo source as two separate channels, and if only one of them carries signal, that is exactly what lands in the recording — sound on the left, silence on the right.
The useful part is that OBS documents this case directly, symptom and fix in the same breath. Its Audio Mixer guide says:
"If only the first meter lights up, your viewers will only hear that source in their left channel. You can enable "Downmix to Mono" in the Advanced Audio section of the Audio Mixer to force 1 channel audio to 2 channels."
That is a diagnosis you can run in five seconds and a fix that is one checkbox. Most write-ups on this problem send you into driver settings first.
What "only the left channel" actually means in OBS
The Audio Mixer is not showing you one blob of sound. It shows you channels, and the number of meters you get tells you how OBS is treating that source.
OBS's own descriptions of the three cases:
- Mono, one channel: "(1 Channel) Mono source Viewers will automatically hear this in both left and right channels (headphones/speakers)"
- Stereo, two channels: "(2 Channels) Stereo source Left is shown first, right second. Viewers will only hear these as they're assigned."
- Surround, three or more channels: "(3+ Channels) Surround source Ordered as Front Left, Front Right, Front Center, LFE/Sub, Rear Left (5.1), Rear Right (5.1), Side Left (7.1), Side Right (7.1)"
The second bullet is the whole story. "Left is shown first, right second" means the top meter on a stereo source is the left channel and the one below it is the right. And "viewers will only hear these as they're assigned" means OBS does not helpfully spread a one-sided signal across both sides. Whatever is on the left channel stays on the left channel.
So a microphone or capture device that is physically delivering signal on one channel of a stereo pair produces precisely the file you are complaining about: sound assigned to the left channel, nothing on the right.
One setting shapes what you see before any of this: OBS notes that "OBS Studio defaults to Stereo audio. This can be configured in the Audio section of the application Settings. You will only see volume meters up to the number of channels configured." That last clause matters when you go looking — the meter count you are reading is capped by the channel setting in Settings → Audio, so check what that is set to before you conclude anything from the meters.
The fastest fix: Downmix to Mono
Run the check first, because it takes seconds and it decides everything after.
- Open the Audio Mixer dock and watch the source while it is making sound.
- Count which meters move. If the first meter is the only one moving, you have the documented case.
- Open the Advanced Audio Properties. OBS's instructions for reaching it: "In the Audio Mixer dock, click the gear icon at the bottom left to open up the Advanced Audio Properties window" — and "Note: you can also access this from Edit in the menu bar."
- Enable Downmix to Mono for that source. Per OBS, this forces "1 channel audio to 2 channels."
That is the officially documented route. OBS describes the effect in exactly one line — it forces "1 channel audio to 2 channels" — and the knowledge base does not say anything beyond that about what the setting does to the source signal.
Two honest caveats. OBS phrases the whole passage in terms of what viewers hear, because the Audio Mixer guide is written around going live; the setting itself lives with the per-source properties in the Advanced Audio section. And OBS's knowledge base does not spell out any recording-versus-streaming difference for this checkbox, so if that distinction matters for your workflow, check the official documentation rather than assuming.
Before you re-record anything, confirm what is actually in the file you already have. The quickest way is to pull the audio out and listen to it on its own, without scrubbing through video:
Try it right here
Runs in your browser. Your file is not uploaded anywhere.
This runs in your browser — the file is read from disk, processed locally and handed back, never uploaded. Know its limit before you draw conclusions from it: it reads the first audio track only (-map 0:a:0 internally). If you recorded to multiple tracks in OBS, this tells you about track 1 and nothing else. To pull a specific track, you need -map 0:a:1 on the command line — extracting audio with FFmpeg covers that. The same job in a plain single-track case is what extract audio from video is for.
This check is also what OBS itself tells you to do: "Finally, be sure to record a session as you normally would and then listen back to the file before going live."
Other causes, in order of likelihood
A surround source you did not expect. OBS states that "OBS Studio automatically downmixes surround sources to Stereo unless otherwise specified," and it lists the channel order as Front Left, Front Right, Front Center, LFE/Sub, and so on. If a source is arriving as surround, the channel ordering — not your microphone — decides what ends up where.
The channel setting in Settings → Audio. Because you "will only see volume meters up to the number of channels configured," the meter test reads differently depending on that setting. If OBS is configured for Mono, you do not get a second meter to compare against, and the "only the first meter lights up" symptom cannot be read the same way. Confirm the setting, then read the meters.
You are looking at the wrong problem entirely. One-sided audio and no audio have different causes. If the recording is silent rather than lopsided, the usual explanation is multi-track recording: OBS says "all standard video players will only play back one audio track at a time," so audio recorded onto track 2 is invisible to an ordinary player. That case is covered in OBS recording has no audio.
Clipping mistaken for a channel problem. OBS defines clipping as "the distortion that is heard when an audio signal cannot be accurately reproduced by the gear through which it is passing," and points at the peak indicator: "Top Dot (Static/Moving): Peak Displays the loudest the meter has been in 20 seconds, a great way to see if you're clipping." Distortion on one loud source is not the same problem as a dead channel, and Downmix to Mono will not fix it.
How to tell it worked
Record a short test — thirty seconds is plenty — and listen back to the file, which is the check OBS asks for above rather than an extra step invented here.
While recording the test, watch the mixer: with the source downmixed, the lopsided reading that started this should no longer be what you see. Then listen to the file itself, because the mixer shows you what OBS is handling, and the file is what your audience gets.
FAQ
Why is my OBS recording only playing in the left ear? Because the source is being treated as stereo and only its first channel carries signal. OBS states it directly: "If only the first meter lights up, your viewers will only hear that source in their left channel."
Where is Downmix to Mono in OBS? In the Advanced Audio section of the Audio Mixer. To open it, OBS says to "click the gear icon at the bottom left" of the Audio Mixer dock, or reach the same window "from Edit in the menu bar."
Does Downmix to Mono reduce audio quality? OBS describes what it does — it forces "1 channel audio to 2 channels" — but the knowledge base does not discuss a quality cost. Record a test and listen back before committing to it for a real session.
Can I fix a recording that is already one-sided? Nothing in OBS's documentation covers repairing an existing file, so treat that as a separate editing job rather than an OBS setting. Fix the source first so the next recording is correct, then decide what to do with the old file.
Is my microphone broken? Not necessarily. A stereo capture path delivering on one channel produces exactly this, and OBS's fix is aimed at the mixer rather than the device. If the meter test points at a single lit meter, start with the documented setting.
Quotes are from OBS Studio's own knowledge base — the Audio Mixer Guide and the Multiple Audio Track Recording Guide — checked 16 September 2026. The knowledge base describes itself as a work in progress, so verify settings against your own build and the official OBS help pages. More fixes like this one in the fix category, and the full browser-based toolkit is at all Clapr tools.
