in my opinion (using bassbox pro6 & X-over pro 3, CLIO & RTA audio Control SA3051):
Tweeter HPF 4000hz ,slope 12db
Midrange LPF: 1000hz-1600hz, slope 12db. HPF: 250hz-200hzhz,slope 12db (if u volume box is minimal 1,2Liters )
Midbass LPF: 160-200hz, slope 12db , HPF: 63hz-100hz slope...