With this setup, the left and right surround audio will be duplicated and play out of both sets of in-ceiling speakers. If I were you I would just use the pair of in-ceiling speakers behind the sofa. But try it both ways and see what sounds the best to you.

Hey GuitarSupestar 

Thanks for your reply,  then the sound shouldnt be degraded just duplicate it.?  since day one I have been using all 4. I can give it a shot disconnecting the duplicate one 

Thanks again, 

It will be degraded.  Surrounds have two functions, ambient sounds like rain or traffic, and directional cues, like bullets whizzing by or off screen voices.  If those directional cues are coming from both in front and behind, the directionality is lost.  More speakers does not mean better sound, and often means worse sound.

Hey Jgatie, 

Thanks for you reply, I would remove the 2 in front. 

Hi Jgatie and Guitar,

I removed the 2 speaker infront and improve a lot the sound. Thanks for the feedback