Fix audio that plays in one ear
Voice only in the left or right side of your headphones? fix.fm spots it and puts the voice in both ears. Free, in your browser, nothing uploaded.
Never uploaded. Everything runs in your browser.
What's happening
Audio in one ear is when the voice plays only on the left or right side of your headphones. It happens when a mono mic is plugged into one side of a stereo input, which is common with USB interfaces, cameras and recorders that have two inputs. On speakers you might not notice, but on headphones it's uncomfortable, and anyone listening with one earbud may miss it completely.
fix.fm compares the level of the left and right channels. A gap of 6 dB starts to sound lopsided, 10 dB clearly leans to one side, and at 20 dB most of the audio comes from one side. A large gap does not mean the other microphone is empty. Different voices are mixed into both ears, even when one is much quieter. The quieter person still needs a separate level adjustment to match the louder person.
Not sure if it's the file or your headphones? Run a left and right headphone test on tonal.fm, our sister site. If both sides play there, the problem is in the recording.
How far the one-ear fix goes
Audio in one ear is the one problem on this site with a complete fix: the sound that is there goes to both sides. The decision is how. Adding left and right together is the obvious move, and when the right side holds a quieter, later copy of the left, adding them colours the voice. The three cases below are two readings placed in software so the check, the copy and the mix can each be heard and measured.
Two readings placed on the left and right in software, each through this page's fixer at full amount. Every clip is matched to -23 LUFS so only the sides differ. Use headphones.
One side dead
Headphones on. The voice is in your left ear only; the right is silent.
Dead side, after the fix
The left side copied to both. Nothing else about the voice has changed.
Same voice, leaning left
The voice on the left, and the same voice 12 dB down and 1 ms late on the right. It sits off to one side.
Leaning take, plain mono sum
What adding left and right together does: centred, but the late copy puts a faint hollow ring on the voice. Compare the vowels with the next clip.
Leaning take, after the fix
fix.fm hears the two sides carry the same voice and copies the louder one to both instead of adding them. No ring.
Two people, one each side
One voice on the left, a second voice 10 dB down on the right. On headphones each person is in one ear.
Two people, after the fix
Both people in both ears. The second voice is still the quieter one; the fix centres the sound, it does not balance the speakers.
Public-domain LibriVox voices. The sides were built in software; nothing here came from a real two-input recorder, and the late copy is a delayed file, not a second microphone.
| Case | Gap between sides | Check | Same sound | Left / right |
|---|---|---|---|---|
| One side dead | 96.4 to 0 dB | severe to fine | 0.00 | -26 / -120 to -26 / -26 dBFS |
| Same voice, leaning left | 12 to 0 dB | moderate to fine | 1.00 | -26 / -38 to -26 / -26 dBFS |
| Two people, one each side | 8.4 to 0 dB | mild to fine | 0.03 | -26 / -34.4 to -26 / -26 dBFS |
The dead side is the plain case. The check reads a 96.4 dB gap, severe, and the fixer copies the left side to the right: the output's left channel is the recording's left channel, sample for sample, and the right now matches it.
The leaning take is the decision. Both sides carry the same voice, and the same-sound reading of 1.00 says so, so the fixer copies the louder side rather than adding the two. Adding them would have worked too, in the sense that the check would read fine afterwards, but the late copy would leave a comb on the voice: measured against the left side's own spectrum, a plain sum strays 1.5 dB on average with a notch of -2.1 dB, while the fixer's output strays 0 dB because it is the left side. The middle figure is that comb.
Two people is the honest part. The same-sound reading of 0.03 tells the fixer these are different voices, so it mixes them, held at the louder side's level, and the check goes from 8.4 dB, mild, to 0. But the second voice sat 8.4 dB under the first as recorded and sits 8.4 dB under it afterwards. This fix puts both people in both ears; it does not make them equally loud. For that, split the original stereo channels in an editor that supports it, such as Audacity. If you already have separate recordings, put each person on their own track in our editorand turn the quiet one up. Our editor does not split stereo channels yet. See uneven podcast volume for why one gain cannot do it.
What this does not prove: these sides were placed in software, so the leaning case has one clean delay. A real second microphone picks up room and distance as well, and a copy that is far later than a few milliseconds starts to read as a different sound; the same-sound number is what decides it, and the check shows it before the fix runs. How we test has the pass marks behind the check.
How it works here
- 01
Compares the two sides
It measures the left and right channels while someone is talking, and works out which one is live.
- 02
Puts the voice in both ears
If one side is silent or both carry the same voice, it copies the live side to both. Different voices are mixed, even across a large level gap.
- 03
Stays on your computer
Your file is never uploaded. The fix runs in this browser tab.
Questions
Why is my audio only in one ear?
Most often a mono mic was plugged into input 1 of a two-input recorder or USB interface, and it was recorded as stereo. The mic's sound lands on the left and the right stays empty.
Is my audio uploaded anywhere?
No. The file is read and fixed inside this browser tab and never leaves your computer.
I recorded two people, one on each side. What happens?
fix.fm mixes different voices so both people are in both ears, even across a large level gap. It does not balance them: whoever was quieter stays quieter. To adjust each person, split the original stereo channels in an editor that supports it, such as Audacity. Our timeline editor can adjust separate recordings on separate tracks, but does not split stereo channels yet.
Will the fixed file be mono or stereo?
Stereo, with the same sound on both sides, so it plays in both ears everywhere. Only the first two channels are changed; any extra channels are left as they were.