Just wondering about the rear firing speakers bit... usual placement has a wall behind the front speakers, I'm wondering if spacing between wall & speaker would have an effect on the sound bouncing or reverberating off the wall and the if dsp has accounted for this effect if so is there an optimal distance placement from wall ? ... i've noticed that with m80's just the open rear port and placement has an effect on sound and sound calibration (sort of a placement sweet spot) so I can just imagine with rear firing speakers that effect would be aplified. have any of you noticed this? what seem to work for the m80's (1 feet rear and 3 feet sides)