alright, not the best at this stuff but the only thing i can think of is, since its ported you need to set your subsonic to the port tuning. when you have your subsonic lower than what your port tuning is your sub will bottom out cause it cant produce lower than your port tuning frequency. so to fix this, talk to your box designer and find out what your port tuning is and set your sub sonic to the port tuning. thats the only thing i can think of. your lpf is fine and leave the bass boost alone. then tune your gain last
