submersive with mbm-12's

I was considering getting 4 uls's or 2 submersive's. I really like the mbm's nearfield and would hate to get rid of them-currently using hsu 3.3's. The affect is truly remarkable and something that I am not sure the submersive will be able to do due to the nearfiled placement (THUMP in the chest). If I get the submersive, how do I cutoff the frequency above 50 on the submersive. I saw a pic of the amp and I didn't see a crossover knob. I know the uls's have them and they wouldn't be a problem.


thanks