Not to confuse the matter further for you, but I suggest you also consider the tripole speakers made by M&K. My room setup is similar to yours (13'x17', with the main couch about 5' below and in front of the rear surround speakers) , and I've been very pleased with the M&K SS-150 THX tripole surrounds I am using. The SS-150's are a good deal more money than the Paradigms you are considering, but M&K has a new tripole model, the K-4, which for $450 (MSRP).
The advantage to the tripole design is that you will get both direct and dispersed sound, which is very helpful when your listening spot is close to the rear speakers. My SS-150's sit atop a tall bookshelf at the back of the room, and their tripole design provides a very nice amount of lateral fill while also providing directional aural clues.
By the way, I have previously tried dipoles, then direct-radiating bookshelf speakers, but eventually settled on the tripole design which I think is an excellent compromise in a surround speaker for room setups like ours.
Here is the link to the web page for M&K's surround speakers if you want to look at their various models:
http://www.mksound.com/surround_speakers.html
The advantage to the tripole design is that you will get both direct and dispersed sound, which is very helpful when your listening spot is close to the rear speakers. My SS-150's sit atop a tall bookshelf at the back of the room, and their tripole design provides a very nice amount of lateral fill while also providing directional aural clues.
By the way, I have previously tried dipoles, then direct-radiating bookshelf speakers, but eventually settled on the tripole design which I think is an excellent compromise in a surround speaker for room setups like ours.
Here is the link to the web page for M&K's surround speakers if you want to look at their various models:
http://www.mksound.com/surround_speakers.html