I have a similar situation with my couch blocking my left speaker. When I had Axioms, I got around the problem by building some ugly, but relatively efficacious, risers which lifted all the drivers slightly above the edge of the sofa. Not ideal, but few things in life are.
When I got new speakers, I opted to set them on the floor to see if I could notice an audible difference. The arm of the sofa is a mere 6 inches, or so, in front of the speaker,blocking the bottom two of four woofers. The top two woofers, midrange driver, and tweeter are unobstructed. Still not ideal, but real world strictures demand compromise.
I notice no difference between the two speakers (YMMV), so, I opted to leave them on the floor. IMHO, If you can get at least two feet, or even one, between the speaker and the sofa arm, you need have no concerns.
As to positioning relative to the walls, the Axioms are ported speakers, so they need at least 3 or 4 inches of space behind them (more is better). Try to place them so that the drivers are
not the same distance from the side walls as they are from the back wall. Experiment with angling the speakers slight in toward your ears (
toe-in) to see what sounds good to you.
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