Bipoles will work even against the walls, but to really get the effect you need a reflecting surface 3-5 feet behind the speaker to give the time-delay that will fool your ears into believing that the rear speakers are farther away than they really are.
Of course you can. But I find dipoles/bipoles work best if they can be placed 2-3 feet in from the back reflecting surface. If you have room for this in a 7.1 system - go for it. If you have to mount your side/rear arrays on a wall, monopole speakers tend to be simpler/better.
Of course you can. But I find dipoles/bipoles work best if they can be placed 2-3 feet in from the back reflecting surface. If you have room for this in a 7.1 system - go for it. If you have to mount your side/rear arrays on a wall, monopole speakers tend to be simpler/better.