Is it better to use the HPF on my amp or the setting on the headunit to send everything under a certain freq. to the subs? I have 2 subs on a 4 channel amp at the moment and setting both HPFs the same would be almost impossible.
The filters on the amp will over-ride the HU. Get them as close are you can. I'm not sure but I think the HPF on the HU will control the filter on the inside speakers, not the sub.
The hu says its for the sub. It has low (50hz), Mid (85hz), and high (115hz). Will it hurt anything if I use the hpf on the amp and don't get to exactly right?