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Detect the working side, preview the repair, then export.
Audio in only one ear is one of the most common recording faults there is: a mono microphone plugged into a stereo input records to a single channel and leaves the other silent. The result is unusable on headphones and half-volume everywhere else. This tool detects which side actually holds the recording and copies it to both.
Almost always a mono source into a stereo path. A lavalier or interview microphone on one input of a two-channel recorder writes to that channel alone; the other records silence. Some cameras and capture devices do the same when a mono microphone is attached. Nothing is missing from the recording — the audio you need is complete on one side — which is why the fix is straightforward and does not involve recovering anything.
The correct repair is to copy the working channel to both sides, producing identical audio everywhere. That is not the same as centring the balance, which adjusts relative levels between two channels that both contain something; here the second channel contains nothing to adjust. It is also why simply raising the level of the silent side achieves nothing. After duplication the result is effectively mono, which for a single-microphone recording is exactly right — verify by listening to each channel individually before exporting.
A mono microphone was recorded into one channel of a stereo input, leaving the other silent. It is one of the most common recording faults, and nothing is actually missing.
The channel that holds the recording is copied to both sides, so identical audio plays everywhere. The result is effectively mono, which is correct for a single-microphone source.
There is nothing to recover — no audio was ever recorded there. Duplicating the good channel is the complete fix.
Balancing adjusts levels between two channels that both contain sound. Here one channel is empty, so it is duplicated rather than balanced.
It will sound correct and identical in both ears, but without stereo width. For a single microphone that is exactly what the recording always was.
