So currently I own two 5DBs that I was using of to the sides at my old place. My new place I only can mount them on the back wall above the couch.

My question would be do you think the 4T off to the sides of my couch would work well for surrounds so I don't have to mount anything on the wall. Plus the 4T have a nice frequency range.

 Let me know your thoughts.

I think the 5DBs mounted to the back wall in bipole mode will be better in terms of surround effect, but for multi-channel music the 4Ts will be better.

So it will depend upon what the primary usage of the system is in terms of music vs. movies as to which will be the best choice.