Attack and release
The compressor's reflexes: attack decides how fast it grabs a loud moment, release decides how fast it lets go.
See it
What it is
Attack controls how quickly a dynamics processor moves into gain reduction after the signal crosses the threshold. Release controls how quickly it lets go after the signal falls back. The values are usually milliseconds, though the exact time-constant definition varies between compressors.
Use a slower attack when the opening crack of a snare or the consonants in speech need to pass through; use a faster one when those peaks need catching. Set release fast enough to recover before the next phrase or beat, but slow enough that the gain does not flutter with every waveform cycle. Around 10 ms attack and 100 ms release is a sensible place to start for voiceover, then listen.
Gotcha: fastest is not safest. An attack that is too fast shaves off punch and can dull T and K consonants; a release that is too fast creates distortion or obvious pumping. Too slow a release leaves the next word or drum hit pinned down because the compressor never got back to zero. Read the hardware carefully too: on a UREI 1176 the Attack and Release knobs run backwards, with fully clockwise being the fastest setting.
Ask AI for it
In FabFilter Pro-C 2, compress this voiceover at 3:1 with Lookahead at 0 ms, Attack at 10 ms, and Release at 100 ms. Set the Threshold for 3 to 6 dB of reduction on loud phrases, then tune Attack just slowly enough to preserve T and K consonants and tune Release so reduction returns near zero between phrases without pumping.