Let's say you have four floor monitors strung across the stage.. And let us say the singer likes hers nice and loud, while the bass player only wants it loud enough to hear for his changes. And the drummer wants his up loud for the couple songs he sings on, but likes to back ut off otherwise. How do you control that from the amp?
The idea here is not we will go across stage and turn them all up and down, the idea is to allow each one to be tweaked for the guy listening to it.
But you don;t have to use it, of course. And have we verified it as an overall level pot instead of a horn control?
The part is a rheostat - a big power pot. In fact, if you demount it and look on the edge of the white ceramic base, it should be printed right on it, something like 50 ohms 50 watts, or whatever.
On some simple floor wedges, PV just wired it in series with the speaker. It was wired as a variable resistor then. Two leads. COnsidering all three are wired here, it would be some different arrangement. it is part of the circuit. If you don;t want it, instead of replacing it with a large resistor, why not just leave it turned all the way up?
The crossover is extremely simple, trace it out on a sheet of paper. You can then see where the rheo is wired in.