Forgive me, as this question has been explored to death on here, but I still don’t fully get it. Does the SC HP dial only function when it is being triggered by an external source like a kick drum, or is it still functional when you’re just inputting your bass signal to the input jack?
It operates without any external source plugged in. It's a very useful feature, to keep the lows from causing the compressor to squash. Experiment with the knob, while you play your open bottom string and/or roll some bass boost up if you have an active bass.