Marjan,
Here is the tell all story about the top cabinets:
http://srforums.prosoundweb.com/index.php/m/389133/19717/?sr ch=Box#msg_389133
The lower top box has four 8” cones and no HF drivers, it gets the HF above heads and provides more low mid, the HF can outrun the mids without the extra box.
After using these cabinets for a few years, I have to say that the angling between cabinets and the whole stack is absolutely critical for even HF coverage, a few degrees can make a huge difference.
The driver count: eight Lab 12, twenty eight Eminence Alpha 8, ten EV DH1Amt-16.
I’d like to carry twice as many subs, but can’t fit any more stuff in my 5x8 trailer with eight 2x8 monitors, a drum sub, amps, cords, stands, and FOH...
Art Welter