The other side of that wall is plywood with spray foam. The visible side is 2X4's and standard pink insulation. The 10"X10" opening is just a square cut in the plywood. There isn't anything else because this isn't the actual control room. Its a little room next to the control room with a door/hatch that seals tight. All of the wire you see routes thru a finished horizontal slot. Once the wiring is done we are going to install brush strips at the slot so that you cant see into the "dead space".

If i were bringing the cable into the ceiling above the av closet i would take a piece of half inch plywood and attach it to the ceiling (where you would normally attach sheetrock) cut a 10" circle or square and route all of the cable thru the ceiling joists and out of that 10" hole. It would/work look similar to a speaker bracket but instead of just the speaker cable you have all cables in the house coming thru it. This is purely a way to keep all cables coming to a specific point so that they are not hanging in different corners of the room (based on how they were routed into the control room.

Then i would have them build the finished ceiling so that its dropped 8 or 10 inches lower than actual ceiling height. This creates a dead space where all of the wire can hide until its needed. You could also do this just above the racks like a soffit.

Have them put in a 2'X2' ceiling panel/hatch (like attic access) in the finished ceiling. Or you can wait and do it yourself. It should fall behind the racks not directly above them. The idea is you use the hatch to climb half way in on a ladder so that you can route your cables thru a slot or pipes cut into the ceiling directly into your rack.

Using the dead space and cutting your pipes/grommets/slots in after sheet rock allows you to get the room finished and then decide on exact placement of racks and where you want to route cable. You can only plan so far/much with blue prints because you cant see the 4" molding or the 8" deep box on the back wall from the elevator equipment until the house is done.

The dead space lets you store unused cable, create nice bundles that route thru to the racks by hiding the "knot" created by cables coming from all directions in the house and it lets you precisely pinpoint the location where they come out of the ceiling into the rack.