Very good question...
I would say speaker placement (back wall, rear wall, toe in/out) seating position are probably the most important. Of course, recordings and components all contribute to soundstage.
Component contributions to “sound stage”
What components in your stereo system do you think make the largest contribution to your perception of sound stage in your system? Which element or component contributes the least to this part of the stereo listening experience?
Rankings are fine. Justifications or explanations are even better.
kn