Suggestions: Rear R/L surrounds - on wall or bookshelf?

I found a great deal on some used Elac UB5s (FR/FL) and a UC5 (C) for my fronts and just bought them without really thinking about how far I'd be able to set them out from the wall. Now that I'm looking for some rear surrounds to go with these, my room setup and placement has me thinking. I'd like to stick with Elac just for aesthetic purposes and am considering the B4 (rear port) or the 2.0 on wall (bottom port) speakers. My living room is like a rectangle with the right half of it being sunk in. My setup will be in the sunk in portion of the room, so my rear right speaker is either going to be in a corner or very close to a wall and my rear left will not be. I'm wondering if a bottom ported speaker would do better in this situation vs. a rear ported one because the couch is pretty much up against the back wall which won't allow placement of rear surrounds behind me. The pic I drew isn't really to scale - I don't think I'll have a lot of room to try and angle the rear surrounds (or at least the rear right surround speaker) out a little bit, so they'll probably have to be set in the direction as shown. Maybe I'm over thinking this. I will be watching movies, listening to multi-chan SACDs, and some 5.1 live concert DVDs. Suggestions much appreciated. I guess my thoughts are - will a rear ported bookshelf be too boomy that close to the wall (I guess I could always plug the port, huh?)? I'd be lucky to have 6" of space from the wall for my rear right surround speaker. Thanks!

 

Another thing is frequency response. I guess the on wall speaker is geared more towards surround sound - Frequency Response: 70Hz – 35000Hz vs. the rear port bookshelf which is - Frequency response: 48 to 20,000 Hz. Would the on wall speakers take away anything in terms of sound from multi-chan SACDs? Thanks.

 

The current thinking for a 5.1 setup is to have the rears facing directly inward to the listener, just like your illustration. Although if one has space, experimentation is always good.

I'd recommend the on-walls, dunno how to place or mount the left one aside from fabricating something. But with those specs, you should first make sure your AV receiver and/or sub setup allows for adjustments up to 90 or 100 Hz. The 70 in the spec may or may not reflect usable/audible low-end response.