My understanding is that this is a complex question. Largely, the effect is a function of how the speaker interacts with the room. You can experiment with this by moving your setup around ...even into another room. Does it sound the same? Probably not.
Toe-in of the speakers will narrow the soundstage, as will in my experience having the speakers too close to side walls. But, frankly I did not experiment much in this regard.
Have you shot your room with, say R.E.W.? That's a nice piece of freeware that runs on, say a laptop. You will also need a good quality microphone for this purpose ($50 or up), a microphone cable (usually a balanced cable with these mics) and an analog (balanced in) to digital (usb out) converter (I got one of several in the $200-500 realm. I think this is a very worthwhile thing for an audiophile to do unless you have far better ears than I have. You will thus have the tools to explore the invisible world of what your room does when it interacts to specific frequencies from your speakers. (I ended up moving speakers and pasting damping sobathane on the back of artwork, a mirror, the inside of a modern floor lamp,...)
Toe-in of the speakers will narrow the soundstage, as will in my experience having the speakers too close to side walls. But, frankly I did not experiment much in this regard.
Have you shot your room with, say R.E.W.? That's a nice piece of freeware that runs on, say a laptop. You will also need a good quality microphone for this purpose ($50 or up), a microphone cable (usually a balanced cable with these mics) and an analog (balanced in) to digital (usb out) converter (I got one of several in the $200-500 realm. I think this is a very worthwhile thing for an audiophile to do unless you have far better ears than I have. You will thus have the tools to explore the invisible world of what your room does when it interacts to specific frequencies from your speakers. (I ended up moving speakers and pasting damping sobathane on the back of artwork, a mirror, the inside of a modern floor lamp,...)