map stuff in WinISD and spend a few hours playing with volume and tuning and most likely will see. At a certain point you'll see some diminishing returns on spl but click over to cone excursion. Hell at this point figure out all sorts of about winisd... port velocity and such. g'l
As for dampening material - if you're going sealed - cool, it makes the volume pretend it's larger. Ported...same thing but it needs to be secured well. Basically the sound has to pass through the stuff and slow down.. making the back wall of the box "seem" farther away... giving the effect of a bigger box.