My HT had four Infinity P163's and my old Klipsch KV-2 center speaker when I moved here 7/13. I placed the front ported bookshelf speakers on book shelves and the KV-2 in front of and below my 55" monitor (AVR is an Onkyo TX-SR505.). The bookcases were either side of the monitor and three across the back wall, resulting in not enough separation L-R front or back. They needed to be outboard of the bookcases - on stands - but they would run $160-$200 for two proper pair.
Amazon had the floor standing Infinity P363's for $99/ea shipped - and I had just sold some shop tools - so I ordered four of them and a large roll of jacketed #12 stranded in-wall speaker cable and ran same along the outside wall by the floor molding, the white jackets blending with the molding - a temporary installation - still in use! It sounded great - good separation - but the dialog was flat. The next time the P363's were $99, I got one - my right side of the monitor 'center' speaker - and dialog sounded better, but right weighted. I watched - grabbed a sixth P363 a couple of weeks ago - I wired the two 'center' P363's in series as they are reportedly 6 Ohms. I adjusted the center white noise level and love the result. Additionally, my wife praised the sound - and the symmetrical look. I Now have, across the front:
P363(LF) [bookcase] P363(C) [55" Monitor] P363(C) [bookcase] P363 (RF)
The LH 'center' P363 replaces my Polk subwoofer - I don't miss it! Across the rear:
P363(LR) [bookcase] [bookcase] [bookcase] P363(RR)
So, one way to keep similar drivers in your center speaker is to simply use the same type of speakers across the front. And... two separate speakers, one on each side of the monitor, beats the single side center speaker. Of course, if you can centrally mount the center speaker, that would be best. The two identical centers worked for me. If they had been true 8 Ohm speakers, I could have paralleled them instead of series connected them.
