How to make nice sounding drum room???

I have studio room 9m x 5m x 3m. How should I acoustic my drum corner to get the best recording results? On the wall there is acoustic panels from 1m up. I`m planning to put wooden half panel under it, is it ok? Should I put wooden panels all over the corner? On the ceiling above drum area I have also 20mm acoustic panels. Is windows problem? You can see picture at http://www.rohto.biz/forum/monopolistudio.gif Thank you, Azoon

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