I have just moved, and for the time being, because of the size/shape of my room, I have to put my speakers on existing shelves. There's a lot of conflicting advice on how best to do this. Some say to give them as much space as possible - others to wedge them in with books. I have also read that it's a good idea to fix them to the shelves with Bluetack - others say to rest on foam. Have any of you done this successfully, or know what really is best ?