I'll admit I haven't heard Prologic IIz or Audyssey DSX, but I was thinking that a single height channel might produce much the same effect. I know many people would like to put a center channel both below and above their TV, but I've read that this isn't such a good idea considering it would be the same source. A center height might be beneficial, 'though, and for me at least, it would allow much more convenient placement. Can anyone explain why all/both the implementations use stereo height? Any thoughts about making a phantom center height from these stereo channels?