Musical wallpaper - soundscape in front of you as heard from the listening position, on a (whole room, wide beam) laser-like single plane, as if there were a musical wallpaper applied to that laser line somewhere near the boundaries of the speakers themself. This is 2-D.
Tom
I think I understand what you are saying. and don't entirely disagree. There is also a time element to music and the time sound takes to reach your ears from its source(s) which suggests the wallpaper is not static.