ok my question is that on my amp its hpf is 35-250htz and on my headunit is a pioneer and is able to go from 50-125htz. lets just say if i were to set my hpf on my amp to 80htz would it let my headunit set it at 100htz and play at that level. what should i set it on so i can control through my headunit?
Don't get too worked up over what Mr. Spam Finder thinks. I think what you're saying would work. i think it would just be like having two HPF's. they shouldn't intefer w/ one another.
"if i were to set my hpf on my amp to 80htz would it let my headunit set it at 100htz and play at that level"
No
But it will work the other way around it is not really suggested but that is what I do my Amp is set ~100hz and I switch the HU to 80-60-50hz whatever I think sounds best for the song.