Rear surrounds question

[igotcabada]

I'm trying to figure out what I want to do with my back 2 speakers for my 7.1 set up... I currently am using a couple of leftover Onkyo HTiB speakers just mounted flush on the wall (Picture 3 in my gallery), but want to change them out.

I have Monitor 30s on BTech mounts (Picture 4 in my gallery) for my side surrounds and was considering just doing the same thing for my rear surrounds. The problem with that is the speakers on the mounts will be over head and not behind of my 2nd row of seating, and the sound field might be a bit messed up for anyone sitting back there.

Anyone have any suggestions? Are bipole or dipole speakers an option for me (I really don't know much about them)