Guide tracks and the scratch vocals nobody hears
Launch library · evergreen read

Before a final playback vocal is recorded, composers often work with a guide track, a rough scratch recording, sometimes sung by the composer themselves, that establishes the song's basic melody, phrasing and structure well before the eventual lead singer ever enters the studio to record their own polished version.
This preliminary version helps the whole production team, choreographer, lyricist and director included, engage with the song's shape early, long before the final vocal performance exists, letting planning for the visual sequence begin without waiting on a fully finished recording to be completed and approved by everyone involved.
Guide tracks are rarely heard by audiences and are typically discarded once the final vocal replaces them, yet they play a quietly important role in shaping the finished song, since many structural decisions about phrasing and rhythm are effectively locked in during this early, largely invisible stage of production.
Some composers deliberately keep their guide vocals rough and unpolished, wanting the eventual singer to bring their own fresh interpretation rather than simply imitating a preliminary sketch too closely during the final studio session that eventually produces the version audiences actually hear in the finished film.