[kareface]

A few things. A SPL meter can only help you set your levels, to do a full calibration you need more hardware. Second, the SPL meter you have isn't completely accurate. You can download the calibration file for it, but then you'd have to use it with some type of measurement software. I completely agree with big daddy, you should pull the speakers away from the wall a few feet if you can. Also you should consider getting some dampening panels to place behind your mains. Having a solid surface like that will cause a great deal of reflections off the front wall, and being so close to the walls will hurt the imaging of your front speakers. Once again I can't argue with big daddy, raising the sub will help move it away from the point where it's adding the most energy to the vertical node in the room.