What does an arranger do?

Question

When you see the "arranged by" attribution on a score, what did the arranger (typically) do?

Answer 1

The arranger of a score usually changes a pre-composed work to fit a specific need. This could include changing the instrumentation, the form or the feel of the music. For example, a song from Broadway musical with a full pit orchestra and chorus could be arranged for piano and voice. The arranger could also alter the form by repeating or taking out certain sections, creating their own transitions between sections and altering the key of the music. Arrangements of music can stick very close to the original or can also sound drastically different depending on the arranger's preferences. The exact processes used are slightly different between classical music and popular music/ jazz but the general idea is still the same. The arranger takes a piece of music usually composed by someone else (but not necessarily) and changes the music somehow to create a new version of the piece. I hope that answers your questions.

Answer 2

The arranging credit can cover a huge amount of territory, from adapting a piece of music for a particular instrument or ensemble to creating a version of a piece or song with an entirely new feel.

Since you specified seeing the word on a score: one example might be taking a popular song and arranging it for a marching band. The arranger will take the rhythms, melodies and harmonies from the original track and distribute them to the instruments of the band so that it's recognizably the same song, although obviously with a very different sound.

Another example: I was once given the assignment of turning a musical theatre song originally written as a disco number into a piece that sounded like 1930s swing.

Both of these would be considered arranging.