Question about subwoofer placement

[Nik]

Hello all!
Was wondering if there would be a problem with positioning my subs BEHIND my MLs? I am limited by wall space on one side cause its angled for a fireplace. Would I experience any sound problems? One sub would be off for most of the time. Thanks!
Nik

Edit: forgot to mention these are front fired subs

 

[C.A.P]

Take and place your sub at your listening position and crawl around the room and listen for the best bass. Then when you find the spot take your sub and place it there. You are now ready to fine tune the phase and x overall