I'm running one Alpine SWR-1043D (dvc) at 2 ohm from a Hifonics BRZ1200.1D amp. It's in a custom sealed enclosure (XJ cubby subs made by DoubleTapXJ on CherokeeForum). My problem is that the sub seems to have a progressive delay. The bass will hit accurately but will fall behind. I've tried lowering the LPF, adjusting the subsonic, and retuned a few times to see if I made any mistakes. I'm having trouble figuring out the problem. Any ideas?
If it helps, I have a JVC KD-R730BT head unit.