This lesson explains the headroom. Headroom is achieved by careful control of the gain structure in our song. This allows us to have nominal levels for many audio processors that require a certain input level. Also it is very helpful in achieving a good output level which would mean we use enough of the amplitude resolution without risking clips.
This lesson explains loudness. Loudness is a subjective overall volume that we can perceive.
This lesson explains leveling and panning. Leveling and panning is the first important step in getting our arrangement to sound balanced enough so that we can make better decisions on its structure.