It really is a question of psychoacoustics. Even if you find 2 people who have exactly the same hearing, their brain may perceive the sound differently and they will think it sounds completely different. Perception truly is reality when it comes to this. Besides that, people don't hear the same. If you have an individual that is less sensitive to a certain frequency range, their idea of the sound stage will be entirely different. For example, if those same frequencies "raise" the sound stage, they may think the sound stage is much lower.