newbie gear question - please read and help :)

[skel]

Music played is reggae, dance, indy, dubstep. Small outdoor and indoor house parties. All for fun not-for-profit. ALL run off an iPad and macbook. I do house parties (mainly at my house), started with a iPod and a fender twin reverb guitar amp. Worked surprising well but no real bass.. I replaced the guitar amp with a Mackie TH-15A. At first it sounded terrible.. something to do with XLR and balanced to unbalanced. Later I bought a couple of cheap additions and it (at high volume levels) sounded really tight and great. I purchased the following;
(Mx4000 4-channel mixer (lets me do some basic volume level adjustment)
Ultra DI DI 120 (supposdly works for linking unbalanced (ipad) to balanced).)
Anyway with these two additions i again have a hard tight sound for small house parties. Fast forward to today where I added a Yorkville Sub Yorkville Elite LS801P. The sub is loud but really muddy sounding. THe Mackie thump has a hard hit but the Yorkville just sorta throbs... I am pretty sure the yorkville sub is fine and i need to do something with my setup to make it sound better. Help a newb out and if you can and make a recommendation on how to get that sub sounding great