I will only be able to provide a listener's perspecive no clue on the "how" side. I found that Apogees (particularly Divas) had what I would consider a pretty generous sweet spot from side to side, though the soundstage changed considerably as listening height changed, necessitating careful adjustments (in my room, with my setup).
Compared to a number of dynamic speakers with great imaging (Avalon and Kharma are two manufacturer's whose speakers I have owned more recently), the sweet spot on the Apogee Diva was huge! (at least in the range of positions from which you could appreciate the near-full width and depth of the soundstage)
Hope that helps at all...
Jacob
Compared to a number of dynamic speakers with great imaging (Avalon and Kharma are two manufacturer's whose speakers I have owned more recently), the sweet spot on the Apogee Diva was huge! (at least in the range of positions from which you could appreciate the near-full width and depth of the soundstage)
Hope that helps at all...
Jacob