OH MY GOD I have found a solution to an issue I've had with my #Behringer #XAir #XR18 audio mixer for YEARS now.
See, each channel has a compressor, and they support #sidechain/key input from another channel. Which is nice for a "ducking" setup: Dim the music while you're talking.
But it always triggered on a _mix_ of the actual channel's signal and the trigger signal (coming from another channel or bus). Which made it totally useless: The music dimmed when _it_ became too loud, too!

