HI Jack:
These are an excellent choice. The angled speaker was first created as an LCR front stage solution. But the angled speaker provides more flexibility for ceiling placement for Rear Surrounds, Center Surrounds and Atmos/DTS:X Speakers. The key to any in-ceiling speaker setup for Home Theater is to have the ability of aiming the tweeter directly at the optimum viewing/listening area. The 15 degrees of the mid woofer plus the 5 degrees for the pivoting Tweeter providing 20 degrees total.These new top of the line ACE-870 feature the same Kevlar cone and metal dome tweeter as our MK series with the new perfect edge Trim-less grill design (held on by multiple extra strength magnets).
And yes one of the speakers will work fine as your center channel.
TL/3886