I'm expanding my home theater with surround back speakers, and I'm wondering which will give me the better result. The price is the same, and I'll be able to install the MPX into a drywall ceiling area which will look nicer. However, I'll only have one speaker (which may or may not be enough for surround back). I can't go with the invisa 525 or 650 because these are not really meant to be mounted into ceilings (can't direct the speaker towards the listener like with the MPX).

On the otherhand, 2 more supersat 3's will be able to go on the back wall and i'll have two of them. But they'll look a little our of context (This will be the kitchen wall, mind you ).

Would a single MPX equal 2 supersat 3's in terms of surround back setup?

I'll only have one speaker (which may or may not be enough for surround back).

Most receivers do not support 6.1 (single back speaker) setups. Better make sure yours does before going any further.

I can't go with the invisa 525 or 650 because these are not really meant to be mounted into ceilings (can't direct the speaker towards the listener like with the MPX).

I think maybe you mean the HTR 7000, the MPX and 525/650 all fire straight out (rather than the 30 degree HTR).

Would a single MPX equal 2 supersat 3's in terms of surround back setup?

No, MPX (or HTR) is a single channel speaker, you'd need a pair to duplicate a pair of SuperSats.