yes^
i can change all that in my HU but its easier and more convenient just to control it with the knob
my sub level on the HU goes from -6 to +6 and i was told to put it at -6 my the shop i go to but i didnt like that so its at +4 now
this is was my amp says(settings on the side)(easier just to post a pic)

the gain is just both max and the low pass is at 50hz and where it says remote is where the knob goes