So For several years I've have an Infinity Modulus II 5.1 system and recently I added two 6" Polk ceiling speakers over the sofa making it a 7.1. I then upgraded the receiver to an Onkyo 717 and its Audyssey 2EQ detected an ERROR with the center speaker. I checked it and the tweeter on the center is gone. I emailed Infinity/Harman about a replacement tweeter, but no answer yet.
So for now I connected both ceiling speakers to the CENTER OUT on the receiver and all the other spakers to include the center (double through surround L/R) are connected as surround. I intend to fix the center speaker, but for now I'm liking this set up! Voices are nice and clear since they a over the sofa and the surround effect sounds good. Is this a format used by others? Am I missing a lot in having it hooked this way?