ngsm13
5,000+ posts
BSEE
Eh.That is what the bracing is for. Besides, 1/4 inch thick fiberglass is harder and stronger than 3/4 inch wood. If you use 3/8 in wood with 3/16 thick fiberglass on top, it will be plenty strong for a normal box. I wouldn't load 6 15's in it though.
Eh.
How much you want to spend on shit...
nG