Ok. My guess is the kenwood HU. I had a kenwood, for like a day.. Piece of **** that wouldn't drop a single low hit. All the speakers were crackly too. Yea, I had eq, hi/low pass filter, and sub output set properly. It was just a bunk HU. So I switched to a pioneer and love it. When this one goes, I'll get another pioneer. You need to do several things to adjust on an aftermarket HU. Things like the 3 things I mentioned before. Also, anything above 65% is distortion. What I mean is, if your amp isn't tuned properly, i.e. gain, frequency response, hi/low pass filter adjustments, etc., then your gonna have poor SQ. someone mentioned adjusting your SLA. The SLA is the level of volume increase or decrease based off of the tuner volume. Generally -4 to +4 is the range of adjustability. You should have your hi pass filter set to about 80Hz (or higher for less bass to speakers). Turn off the loudness setting if it's on! Make sure your amp has its low pass filter on. Report back.

 

My speakers aren't wired to my amp

 

Right. As you don't have a 4 channel amp, wired to any of your non component speakers. Your amp and head unit: those two needing to be properly tuned..