i'm trying to build a box for my 2 12" ssd's but i'm having trouble with port displacement and tuning. the tuning calculators ask for box volume but i can't give that to them until i know the port displacement, which depends on the tuning. can someone help? i want at least 1.8 cu ft per chamber tuned to 33 hz. needs to be 32" wide, 16.5" tall, and under 19" deep