Those black connectors aren't XLR, they're made to accept Neutrik connectors. XLR don't twist to lock, either.
WRT the cable in the walls for the line level signals with XLR connectors- cable isn't balanced, the circuits in the equipment are. Cables like that are called 'shielded twisted pair' or, if it has four conductors plus the shield and 'drain', 'quad shielded'.
Shielded wire isn't used for speakers and part of the reason PA and quasi-PA amps have Neutrik is due to the higher voltage and current that comes with much higher power- don' do it.