I have a pair of JBL LXE 330s that I want to mount on the walls for my rear channels. These weigh about 15 lbs each. Due to the layout of my room, I need to mount them above doors. So they will be about 7.5-8 feet high. What is the best way to mount them? I was thinking about building shelves and firing them (behind my seating position) straight out towards each other. Would the shelves be a good idea, or are brackets better?