I’ve read a bit about how adding a subwoofer to a 2 channel music system isn’t just about adding bass but taking the lower frequency work to the sub so the mains can shine.

I have a Cambridge CXA81 that has a mono sub out, but the crossover setting would be on the sub not filtered at the amp.

So is this actually taking the load off the mains, or just adding TO the mains? Or (newb ass question here) is the lower frequency going to the sub because that… how do i say… window is open now?