There was a time when EAW was king of the hill and their KF-850 trap box based array was the most popular large PA system in the world but because the box was produced for so long, it went through different revisions and versions.
Version Z / Rev 1
A 3-way triamplified full range system in a trapezoidal en-
closure. Includes a 15-in woofer in a wave guide cavity with
ARC™ device, a horn-loaded 10-in midrange cone and a 2-in
exit compression driver mounted coaxially in the wave guide
cavity on a 55 x 40 constant directivity horn..
I haven’t verified that the trap angles equal roughly 1/2 of the 55 degree horn pattern but since I’ve seen a million of these cabinets butted up against each other, it could be that one of the main reasons the cabinet became and then remained so popular was that the angles were idiot proof. Just push them together and the splay was correct regardless of how many boxes you used for an array.
The question to ask is which version of the KF850 are we talking about and can you mix and match the different versions. I guess the obvious answer is that people DO mix and match because they don’t realize there is such a variety of the KF850 and so who knows what a KF-850 rig is made up of any more.
Unlike Meyer Sound products where they make it a selling point that you can buy a cabinet they make now and 10 years from now, if you add more of the same cabinet to your stock, all of your cabinets will match, EAW appears to have taken the route of “fix it as you go” and so here is an article that mentions the “Z” version.
Version Z? That was 2004. Through out the various revisions of this cabinet, there were different brands of drivers (TAD,RCF,