Trailer music (a subset of production music) is the background music used for film previews, which is not always from the film's soundtrack. The purpose of this music is to complement, support and integrate the sales messaging of the mini-movie that is a film trailer. Because the score for a movie is usually composed after the film is finished (which is much after trailers are released), a trailer will incorporate music from other sources. Sometimes music from other successful films or hit songs is used as a subconscious tie-in method.
The music used in the trailer may be (or may have suggestive derivatives from):
Music from the score of other movies. Many films have tracked their trailers with music from other campaigns, such as Dragonheart, Gladiator, The Lord of the Rings: The Two Towers, Dragon: The Bruce Lee Story, Edward Scissorhands, Come See the Paradise (27 times), Aliens (24 times), Bram Stoker's Dracula (18 times).
Popular or well-known music, often chosen for its tone, appropriateness of a lyric, or familiarity.
Classical music, such as Mozart's Requiem (Cliffhanger), Beethoven's 9th symphony (Die Hard), or Carmina Burana.
Specially composed music. One of the most famous Hollywood trailer music composers, credited with creating the musical voice of contemporary trailers, is John Beal, who began scoring trailers in the 1970s and, in the course of a thirty-year career, created original music for over 2,000 movie trailer projects, including 40 of the top-grossing films of all time, such as Star Wars, Forrest Gump, Titanic, Aladdin, The Last Samurai and The Matrix.
Songs, which may imitate recognizable (but often expensive to license) songs.
"Library" music, which is previously composed production music. Trailer music library companies typically do not offer their music to the public and develop and license music exclusively to the motion picture studios.
