What does the arranger do in a song?

Question

I know the job of both composer and lyrics writer ..

but wut doesthe arranger do?

Answer 1

The arranger decides which instruments play which parts. Sometimes there is a key change involved.

Answer 2

The arranger does the "arrangement." In many cases, an arranger takes a musical piece that has already been composed in a certain key for certain voices/instruments and changes it by transposing it into another key, by re-writing it for different instruments and/or voices, by changing the "style" (say, from classical to jazz/swing), or any combination of the above. But if an arranger is working with a composer who is writing a song, the arranger is the one who figures out which instruments and/or voices will be used for which parts and actually helps the composer to "translate" the song he's writing from an idea in his head to music on the page, which is then played or sung and becomes reality.

Answer 3

"to adapt (a composition) for a particular style of performance by voices or instruments."