I'm in agreement about series 6ths, they do get it done down low. A half octave tuning has been my go to, as exact as I can make it... lol. Sometimes I crunch #'s and adjust volumes to get rid of that .4hz needed to make exact. No wonder I get wound up and need a break when a design is completed.
I was talking about big spl #'s down low. In my experience usually the only way to reach those goals when tuned say 28hz is either a hi-power system on some brutally capable subs or just become King-Kone. No replacement for displacement ya' know?
I love doing 6ths but avoid getting too involved, things like walled coupes for example will have you driving around double checking the measurements given. I like to stick with blowthru 6ths. I'm finishing up another one today for a friend. I'm sure it won't be a brutal as the last one he built but should do great as long as he dosen't slag the coils again.
SoloX-12s this time