I'll try to answer Viridian's question:
When I go to concert in good venue and close my eyes, I often hear a clear placement of instruments. I certainly can't tell placement of each 'line' violinist of large symphony orchestra, but able to place small jazz or chamber quartet that performs with no mikes in Minnesota Symphony Hall, Place of Arts(Montreal), Gesu(Montreal).
When I go to concert in good venue and close my eyes, I often hear a clear placement of instruments. I certainly can't tell placement of each 'line' violinist of large symphony orchestra, but able to place small jazz or chamber quartet that performs with no mikes in Minnesota Symphony Hall, Place of Arts(Montreal), Gesu(Montreal).