Acoustic panels

I made four acoustic panels (29" x 16" each) out of some extra dynamat, and 1/2" MDF. My problem is that I really have no idea where to stick 'em, especially in regards to height. The room is is 11x12x8, and the highs are brighter than bright; three songs and i'm down for the count. I would appreciate any advice, theory, whatever. The speakers are hales rev twos.