What is vocal production?

Answer 1

The best-sounding harmonies often come from a group of individuals simultaneously harmonizing around a single microphone. While that's not physically possible for the solo home-studio harmonist, one approach is to send your recorded individual harmony parts to a loudspeaker and then mic that up in a room. The same technique can be used to create stereo backing vocals by panning a combination of closely miked and ambient room tracks.