Yah, those look like they need some bracing, Stick a couple panels that should fit right in there, ought to stiffen it up a good deal.
check these out:
www.speakerplans.com/forum/forum_posts.asp?TID=13782
It looks like those have the center bottom brace extending much further than yours, and they also have a horizontal brace.
I'd do it ASS scoop/punisher/USB2 style and extend it all the way to the front, and not make the braces too deep.
check out the last two pictures in this tread:
www.speakerplans.com/forum/forum_posts.asp?TID=8349&PN=2
I'd do it like either of those, or if I wanted to get fancy, curve it some like that guy who wont disclose what he did with the chamber in the "USB2"
Edited by: bitcore