Hi, so I was trying to research through the internet to see why my amp might not be performing like it should and stumbled upon this website and hopefully you guys can answer my questions and help me find a solution. So I have an Alpine PDX-F4 amplifier and I don't believe it's putting out the power it should. My speakers barely move, like almost no excursion whatsoever when hooked up to the amp but when I hook them up to my HU they start moving and having a more defined bass. While they sound muddy, and really bad off of the HU there is a noticeable difference in bass and they actually move significantly more than when amped. I have all filters on the amp off so that should be allowing a full signal and not causing the issues I'm having? I've tried turning up the gain past the point where I set it with a DMM and while it moves slightly more, it's nothing compared to what the HU was doing. I could take a video if that would help. I'm running 4ga wire from the battery to a distribution block and from there 4ga to my two amps. My battery is 14.02v running and the amp is recieving 14.02v when running. What else to try, and check? My ground is well sanded and firmly attached, not a spec of paint left.