You sure ? I am building eight subs, two of each driver model. Mach 5 Audio,CSS ,SoundSplinter and Acoupower... Here check these... More comming... I will order a second IXL18.4 as well as two MJ-18's very shortly... OT... Acoupower 18 driver (second one almost here)... A monster in the sub world, SPL and SQ monster. With a price to match its quality.