I have a pair of 2x15" tops. Both of the 15's are run up to the crossover point to the 2" horn. They were originally loaded with eminence Kappa Pro 15a's. I always hated the terrible sounding reproduction in the lower midrange, vocals don't project with these cabs... a pair of ancient JBL4560 cabs loaded with under-powered JBL2220b's will stomp all over them for good sounding vocal projection. I inherited these 2x15 cabs a couple of years ago without the Emininece speakers when we replaced them at the club with a pair of SR4731X's. I reloaded them with 4x JBL E140's I had kicking around which have a more prominent bump in the midrange response with no improvement. However, in the cases with either type of speaker loaded in the cabinets, the issue is cleared up with the 2x15's if one 15 is disconnected. Clarity is VERY noticeably improved with them in that case because of the lack of interference from the second 15. I haven't looked into it, but I remember reading somewhere that an MTM layout of the components minimizes the issue instead of an MMT layout as these cabinets are.