In the band I play in, we have a PA. We have JBL's for the speakers, the bass bin's are MPro MP255S Subwoofer . And for the tops we have SF25 Dual 15 2-Way Speaker Cabinet . The amps we use are Pevey or Mackie with more power than we need. The problime is we have a hard time getting the "in your chest, moving THUMP"? Do we need to trade these for the open Faced 18" speakers MP418S 18 Subwoofer, or add anther set of MPro MP255S Subwoofer ? ANY Idea's or sugestions we be a huge help!!! thanks. P.S We play cover tunes in the rock style, STP, Bush, Greenday, Black Crows, Santana, We have used PRO sound guys and we still can't get the "in your chest, moving THUMP"