Hoping this is the right place to post this. Sometime in the near future I'll be replacing the 18 in my homemade cab. After playing with modeling in WinISD, I want to put a SSF in there. I want to build one, buying one is not an option! (Unless it's less than $40). I'm quite capable of building it, but I don't know what values I need for the inductor and cap. Just looking for a simple 12/db butterworth, nothing fancy. New driver will be 8 ohms and eventually pushed with 300-400 watts. Looking for a x-over point of 35Hz. On a side note, I've seen the PFMOD's adjustable filter, but not sure how well it will work with the signal being converted from 1/4" or XLR to RCA.