what to use to angle a center channel speaker down


so that it points more directly at the listening area? it sits on a shelf above my rptv. want to make sure that it doesn't add anything to the sound (no vibrations!) and that it doesn't allow the center to slip downward.

thanks for your thoughts!
davidwb
I use and old mouse pad cut up into smaller squares. I stack 3 in each corner of the rear and in the front I use a Square on each end. Works pretty well IMHO.
How about a pair of door stopper? Or to be more sophisticated, order Sorbathane pads from an industrial supply company (like McMaster-Carr) and build one to spec.