I have two sundown sa15s in a dual ported 6.5 cube 33hz box.. I just recently bought them both and a hifonics brz2400.1d and had the subs wired down to 2 ohms for 1700 watts rms. For some reason they just don't seem as loud as I anticipated. I have all 0 gauge wire. All settings on the head unit are at neutral. Gain is set around halfway between one and two if you were looking at a clock. All of the filters are at various positions not knowing exactly what to do with them. I dont have any dimming of my headlights and my truck already has a high output alternator so I have seen no voltage drop. I have lots of friends with much lesser quality subs (kicker, bazooka, American bass, etc.) and crap amps (boss, power acoustik, etc), and yet their subs seem to be hitting harder than mine. I tried tuning the amp myself with a multimeter and a 50hz test tune and I thought I had it all figured out only to turn my head unit up to 3/4 volume and barely hear bass at all. I don't understand what my problem is and it's really bumming me out that these 15s aren't beating like I thought they would. I don't want to crank the bass knob or gain up only to make the subs start clipping and ruin what I have put my money into. All of the filters on the amp are starting to confuse me also. I'm not necessarily new with car audio but I've just recently started wanting my stuff to be done right. There are not any local shops that really know what they are doing any better than I do and I always would rather do things myself. Any help or possible solutions would be greatly appreciated.