Makeup Gain
Definition
Gain added after compression to restore the output level to approximately the same loudness as the uncompressed input. Because a compressor reduces the level of signals above the threshold, makeup gain compensates for this reduction, bringing the overall signal back up.
In Simple Terms
After a compressor turns down the loud parts, makeup gain brings the overall volume back up to match the original. Without it, your compressed signal sounds quieter than the original — which makes it hard to judge whether the compression is actually improving anything.
In Practice
A vocal compressor applies an average of 6 dB of gain reduction. The engineer adds 6 dB of makeup gain to restore the perceived loudness to its pre-compression level, allowing an accurate A/B comparison of the compressed and uncompressed signal.
Common Confusion
Makeup gain is not the same as the compressor improving the sound. Adding makeup gain makes the compressed signal louder, which your brain automatically interprets as better. Always level-match when evaluating compression.