Makeup gain
The output boost after compression that brings the track back to its old loudness without bringing the squashed peaks back.
See it
What it is
Compression turns peaks down, so the processed track usually leaves the compressor quieter than it entered. Makeup gain is the fixed output boost applied afterwards to restore that lost level. It does not undo the compression: the new, smaller gap between loud and quiet remains. A Teletronix LA-2A has only two knobs, Peak Reduction and Gain, and Gain is the makeup. That is how basic the move is.
Add it after the threshold and ratio are behaving. Start near the average gain reduction, then level-match the processed signal to bypass by ear and meter. A fair match lets you judge whether the compression actually improved the sound instead of automatically preferring the louder version.
Gotcha: makeup gain raises everything leaving the compressor, including room tone, hiss, breaths, and mouth clicks. Automatic makeup modes can also guess too high and quietly overload the next plugin. Watch the output peak, check the next stage, and do not confuse restored loudness with restored dynamics.
Ask AI for it
In FabFilter Pro-C 2, disable Auto Gain and compress this voiceover until loud phrases show 3 to 6 dB of gain reduction. Then use the Gain control for manual makeup gain until processed and bypassed playback match within 0.5 LU of short-term loudness. Keep the processed true peak below -1 dBTP and report the makeup gain added.