We moved into a new house a while back and I'm finally getting around to setting up the home theater system. There are existing in-wall speakers, but I'm a little confused on their placement and the wiring and could use some assistance. All the connections for the speakers run into a built-in cabinet and the TV location is directly adjacent on the wall. I'm running a Harmon Kardon AVR 1700 (just purchased). So the basic setup is a 5.1, but the speaker layout is kinda weird. Picture 1 shows the layout. Picture 1: Layout There are 3 in-wall speakers and 2 in-ceiling speakers and they are as follows: Speaker 1: center speaker (I assume), I can't get the grill of to determine make/model. This speaker doesn't have a 'normal' speaker connection (see below) and I can't figure out how to hook it up.http://www.hometheaterforum.com/content/type/61/id/173047/width/350/height/700 Speakers 2&3: In-wall, both are brand JBL Speakers 4&5: In-ceiling, Pioneer S-910's. I guess i am unsure of how the entire system was designed as it doesn't fit the typical layout? When I wire my speakers to my AVR, which one's should I put in which spot? Now the really tricky part, I only have wires for 4 of the speakers; I am missing the wires for what I assume is center speaker, above the TV. I have some plates with RCA connections, and it appears I could hook to the speakers either via the RCA connections, or by the loose wires, but again, on this primary plate, the connections for the center speaker are absent (pic. 4). It doesn't appear to be an oversight, as the system was likely professionally installed and it looks pretty clean. I have a 2nd plate that runs the old AV connections out to the TV, with a matching plate where the TV hooks in on the wall (picture 5); on this plate, there are RCA jacks that say "power base" and "to c/speaker". I assume the power base if for the subwoofer that I'll need to purchase and the "to c/speaker" is for the center speaker??? But why in the heck does the center speaker connect off of this AV plate? How would I hook this into my AVR? Any ideas? I'm totally confused! Picture 4: speaker plate Picture 5: AV Plate (in cabinet) with matching plate above TV: Notice "power base" and "to c/speaker" jacks... Could anyone offer any assistance/advice? I'm a little confused on this whole thing.