Its a DD9515 in a 3cuft box with 3 4in ports, the lows are powerful and the highs are good, i don't know how high i can go since my LPF is set at 50. The box will be rebuilt soon but it will still get 25hz tuned. ive had 43, 35, 32, and then i used 25 and like it the most. i seen you said from 28hz+ above, with 25 it hits well, all the slowed songs i play are great.