6" vert or 4" horizontal

Hey all. For my Tracking room corner absorbers...I would like to know what would be best. Tracking room is 12.6 x 15. treating 3 corners. Cieling hieght is 9'. Was wondering about the difference between 6" of mineral wool stacked vertically 2' X 8' up the corners. or 4" stacked horizontally 4' X 8'. Or maybe a mix of the 2? Right on thanks guys and gals!! John ps. here is a ref. to my other post regarding treatment. http://www.johnlsayers.com/phpBB2/viewt ... 8676#38676

I'd go with the wider corners; smoother response, deeper air gap for lower frequency absorption... Steve