Hey guys, quick rundown of what I have had in the past (for comparison purposes) and what I have now. Old vehicle, '93 Explorer, Eclipse Head unit, 5433 I think, Diamond Audio 5X7's in all doors, Diamond Audio M6 tweeters in A-pillars, US Acoustics USB 4085 amp for all the above mentioned, Diamond CM3 10" D4 subs in a transmission line ported enclosure, powered by a Diamond D5 600.2 amp. New vehicle, '99Mitsubishi Montero Sport, Eclipse CD5000 headunit(sweet), Eclipse SC8264 Components in front doors (sweet), MB Quart DKK116 6.5 Coax's in rear doors, all ran off same US Acoustics amp, the RL-p12" sub ran off the Diamond Amp (600rms@4ohms), sub is in sealed enclosure, ~1.3 cu ft, roughly .5 lb of polyfill in it. Now to the question. Just got all this hooked up and tried it out this evening. Started with some rap music just to see what this sub could do (first time with one and have never seen or heard them before), this thing pounded like crazy, I was impressed, so moved on to some music I listen to mostly, rock and metal, and ended up being disappointed, just sounded muddy and distorted, so coming to realize maybe sealed was a bad idea for this sub? Have been doing some research on sealed versus ported, and are getting mixed emotions on it. Some say sealed is best for rock type music, some say ported. Have read based off some of the parameters for this sub that it would work best in a ported and not sealed. Just looking for some comments and suggestions on what to do next to make this thing please me! Main reason I went sealed (this is my first sealed enclosure) is due to space, I wanted to actually keep some for once!