Just curious how it would effect the sound if I would cover the sub box walls with dynamat?

 

nice avatar. wonder where you got that? lol, anyways its been done, hell marble inside a box has been done along with numerous other things. do a bit of googling, or try to find snoopdan, he has a great knowledge on this kind of thing. btw, snoop is not on this site iirc. try pming him on caraudio.com, or search for his website.