Basically it's the attack at the beginning of a sound, like the stick striking a drumhead or a pick hitting a string. As opposed to the sustained tone that comes after. So sometimes you want to tame that with compression for a more even sound, but you also need them eg for drums that should 'hit' viscerally and not stroke your ears like a feather.
― Jordan s/t (Jordan), Thursday, 18 April 2024 15:50 (two weeks ago) link