Simplex 4100es Speaker Wiring

On a 4100es system with speakers, do all speaker wires run back to the main panel? I would venture to guess the NAC extenders are only for strobes and horns?

NAC extenders are for powering DC signals only, horns and strobes. 4100 Classic, 4100+, 4100U, and 4100ES panels all support remote transponders that can have audio amplifiers to power speakers. Audio can also be distributed to panels on a network system.