the movie didnt have an actual soundtrack in 1922. the sound the audience would hear would just be an organist. whatever music you heard was added much later. those more popular silent films have a few different soundtracks over the years. such as The Passion of Joan of Arc. (which some say was the great performance by an actor ever.) either way its seriously awesome. find the one with the Jon van den Booren score. its great.
anyway, nosferatu was rereleasd in 2001 with restored picture and a new score. maybe you saw that one.