You should look for manufacturers that design for this issue. Some front ported and non-ported speakers will still sound awful if shoved into a corner or rear wall.
Rear Ported versus Non Rear Ported floor standing
I have a space limitation in our room which means that the speakers can only be placed a max of 6-8" from the rear wall. Does this mean that I need to stay away from rear ported speakers because they all have diminished sound because of the base or will all speakers have the same result . Any recommendations would be appreciated. Have heard at audio shop SF grand piano all off the rear wall, Spendors (rear ported) & Focal Chorus ( not rear ported).