I don't know if this helps but i have 2 12's in a ported box. One amplifier (1800 watts).I really dont know much about the subsonic filter. What is the recommendable tunning for the subsonic filter?
depends what your box is tuned for it keeps your sub from hitting certain notes, becasue in some boxes if you dont have a subsonic filter and your box is tuned for 32hz and the song its hits is 25hz it could blow your sub, you usally set it 3-5hz lower than what your box is tuned too.
