BI/DI Pole Spk Mounting Help

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I just purchased Polk Audio FXI A6 Bi/Di Pole Surround Speakers. They are going to be used in a 5.1 setup as my room is in an old house and not big enough ever to have 7.1.

They are going in a room about 11' x 20' with the TV along one of the small walls so the surround speakers must go on the opposite wall of the 20' long room. Problem is that the sofa is all the way against the back 11' wall and to the right is a huge picture window with no wall room at all for the speaker unless I place it directly in the corner where the main woofer of this speaker and one tweeter would be facing the back wall and only about 1 inch away.

So I was thinking of perhaps mounting these speakers on the Back wall above the sofa. Should I mount them in the corners or so many inches/feet away from the corners? Don't have much wall to work with though.

Also in this kind of setup should I run them as Bipole or Dipole you think?

Anyone have these or similar type speakers with similar type problem?

Thanks