fishy

Hi, I have 2 15" L7's in a 12cuft ported box I built before winter.
I'm looking at building a new ported box for these, basically because it is pretty shoddily made, and i never braced it or anything. What port size for this situation would be optimal? I'm looking at tuning it somewhere between 30-36 hz. My current one is at 30hz, and any frequency that isn't extremely low does not sound good at all.

Also, I looked the thiele and smalls parameters of these up on thielesmall.com , and it appears that they differ from what is in winisd for the sub... which should I believe? I could not find any other places that have the parameters.

Thanks, Fish