I've tried to surf through the plethora of DIY sub info in this forum but bogged down under the mountain of posts. I'd like to build a front (main) sub to complement my LFE sub (which is built into the platform for the second row of seats in the theater... it makes a nice buttkicker as well as LFE sub). The LFE sub uses a JBL 2245 18" driver in 10 cu.ft. vented, equalized. It's flat to 22 Hz and puts out 121dB at 300 watts. Bottom line: What's the best DIY sub assuming that driver cost is not an object -well, OK, under $1000. Cabinet complexity is also not an object (PR, high-order and compound designs OK) but total volume is less than 8 cu.ft. Electrically assisted is OK, i.e. sixth-order vented, equalized. Power will be 550 or 750 w (I have a couple of bridgeable amps available) By the way, my Lexicon MC-12 pre-pro has fully adjustable crossovers and separate delays for the LFE and main subs so that's not a problem.