Component contributions to “sound stage”

Not just the recording - also how a recording is mastered.

Easy to test: take 2+ master versions of the same album and compare at same volume through the same kit.

@michaellent +1! You hit the nail on the head! Soundstage is in the source! Pop/Rock recordings made by multi-tracking in a studio are nothing like a well-miked symphony orchestra where the recording engineer attempts to capture the spaciousness and dynamics of the sound field. Take a listen to John Culshaw's Ring Cycle with Solti/VPO done during the early years of the Stereo Era! Or the Lewis Layton recordings of Reiner and the CSO, particularly Zarathustra and Pines/Fountains of Rome!

@livingwellinco : "The soundstage is unreal." Really, man! 

This is a valid question about one's system.  To reduce an answer to "it has to be in the recording" is not helpful.  Of course.  OP didn't ask how to make all of his music have same.  I think he gets that.  But yes, speakers with high quality drivers and with XO components having tight tolerances followed by geometry/acoustic symmetry of set up in the room/listening position.  Then room acoustics.  My experience is that the prior are about equal and combined account for the largest contribution.  For equipment i found each piece about equal in contribution as I upgraded.  Sure, one bad link and the whole chain fails and you might not detect satisfactory imaging at all.