Don't mix sizes of subs. Do the 12's and leave out the 10. One should never run 3, 5, 7, etc. Try to run even numbers if possible, if not no big deal, just don't mix sizes!!!

10" would be useless, just drowned out by the 12's. As well...12's have punch if box is done properly and amp is sending clean signals. (not clipping)

 

i think 10''s sound better for bass from rock and metal than 12''s do. easier
to get fast hard hitting bass from them