i built a sealed box for this sub .6 cubic feet and it sounds good but it depends on the notes and it just drops off different notes and its loudness lacks majorly im very disappointed in this subwoofer... i have 800 rms going to this sub at 4 ohms and my amp can be wired to 1 ohm at 1600 watts rms and it still sounds like crap? help a brother out.... thanks im at lose and ready to sell the box is air tight its a good box. i m lost ?