while there are lotsa walid points being made here, the indiwidual speakers' inherent characteristics also have a lot to do w/this. dunlavys are known to have a *wery* narrow sweet-spot. one reviewer likened them to being "the worlds' largest headfones". thiels' imho, have a wery wide sweet-spot - i have heard them (facing straight-ahead, which is how thiel recommends it) throw a palpable image even when, for example, sitting to the right of the right speaker, & this was w/no special room treatment. the speakers' dispersion characteristics are important in a wide sweet-spot.
doug s.