I worked in guitar audio effects for a while (the exact opposite of this discussion), but I started playing with stereo guitar rigs and then thought about three speaker setups and beyond.
At a certain point the speakers really start to interfere with each other and you have to worry about the stability of the image at each point in the room...
It occurred to me at that point that you're really starting to approach 3. You're trying to recreate the sound pressure patterns within the room.
That's about the point I moved on to something simpler. Granted my explorations were super simple, but it was a VERY weird thought that got me thinking about the question you've asked.
At a certain point the speakers really start to interfere with each other and you have to worry about the stability of the image at each point in the room...
It occurred to me at that point that you're really starting to approach 3. You're trying to recreate the sound pressure patterns within the room.
That's about the point I moved on to something simpler. Granted my explorations were super simple, but it was a VERY weird thought that got me thinking about the question you've asked.