I was able to angled my vp150 toward my listening position by using the rubber stopper that comes with the QS4 surround. Since I didn't used them to QS4, I used it on my VP150 center speaker. I basically just use to piece of it and stick it at the back end of the speaker base and voila it's now perfectly angled and pointing directly to me....if your center is a little higher this may not work, you may need a little larger thing like what you said a door stopper.