Why a mic ends up in one ear
A microphone is a mono source: one mic, one channel. An audio interface with two inputs, like a two-input Scarlett, hands both inputs to the computer as a stereo pair, input 1 on the left and input 2 on the right. Record or stream that pair as stereo, and a mic on input 1 plays only in the left ear, while the right side stays empty or carries whatever is on input 2. Focusrite’s support team names this, a mono source recorded onto a stereo track, as the usual cause when a mic or guitar is heard on one side only.
Nothing is wrong with the mic. The app you record or stream with has to be told to treat the input as mono.
How to test it
Click Start microphone test. This page asks the browser for two channels and turns off its voice processing (echo cancellation, noise suppression and auto gain), so each side arrives as the interface sends it. Talk into the mic and watch the Left and Right meters:
- Only Left moves: the mic is on input 1 and reaches apps as the left half of a stereo pair. The line under the meters says so, with the level of each side.
- Only Right moves: the same, with the mic on input 2.
- Both move, about equally: the mic reaches the computer on both sides, so it will sound centred. A stereo mic, or two mics, moves both meters but not identically.
- One channel (mono): the browser got a single channel, so this page can’t compare sides. Either the device is mono or the browser opened it in mono (Safari always does): use Chrome, Edge or Firefox for this test.
- Processing on: tick any of Echo cancellation, Noise suppression or Auto gain and the browser mixes left and right together, so both sides read the same. Leave all three unticked for this test.
The Diagnosis also flags a stereo input with one silent channel. To hear the result, record 5 seconds and play it back in headphones.
How to fix it
- OBS Studio on Windows: in the Audio Mixer, open the gear menu of your mic source, choose Advanced Audio Properties and tick Mono for that source. OBS’s own guide warns that when only the first meter of a source lights up, viewers hear it only in their left ear.
- OBS Studio on a Mac: open the properties of the Audio Input Capture source, untick Enable Downmixing and set both Channel 1 and Channel 2 to the input your mic is on.
- Recording software (DAW): set the track’s input to mono (a single input, not a pair) when you add it. The track’s output stays stereo, so you hear the recording in both ears. This works the same in GarageBand, Logic Pro, Ableton Live, Pro Tools, Reaper, Cubase and Studio One.
- Keynote or QuickTime on a Mac: they only take a stereo input and always put input 1 on the left and input 2 on the right. Record in an app that lets you pick a mono input, such as GarageBand. The macOS setting Play stereo audio as mono (System Settings › Accessibility › Audio) only changes what you hear; the recording stays one-sided.
Focusrite notes that DAW settings don’t carry over to streaming and call apps, which handle the input their own way; set those up in each app’s own audio settings.
What the test can’t see
The page measures what reaches the browser, so it can’t tell you how a particular app mixes the input afterwards. It also can’t see a problem on the listening side: if everything, not just your mic, plays in one ear, check your headphones and cable with the speaker and headphone test. For recording levels once your mic is centred, see the mic test for singing and music.
How this page is set up
This is the same microphone test as the standard mic test, opened with different settings. You can change any of them once the test is running. Like the standard test, the page remembers only which microphone you picked.
| Setting | This page | Standard mic test |
|---|---|---|
| Echo cancellation | Off | On |
| Noise suppression | Off | On |
| Auto gain | Off | On |
| Channels | Two requested, with a meter for left and right | One (the browser's default) |