If it's late at night, and it is very very often that I work through the night on a score, I simply turn all the volumes down. This gives me an idea of where the 'real' peaks are musically, and provides strong objectivity to the final full volume mix and master.
So....using earphones, closed back or not, to mix a music that is meant to be played in a theater ( on surround possibly? ) not recommended. I score almost exclusively using full orchestras, and not so big on the 'Pop, Grunge, Trip Hop, thingy.
