I just bought some Paradigm Titans for rears and am real happy with them! Right now I got them on identical metal bookshelfs placed about 6 inches behind the listening position but only 1 foot high. While reading about proper speaker placement it says it should be around 2-3 feet above listening position, will I hear a big difference if i make it 2 and a half feet above? Second, I worry about the bookshelf being metal I'm no sound expert (pretty much the opposite) but will metal reflect sound more or make it worst? It's sitting on top so theres nothing around it except the wall which is about an inch away. Bye!