The Sound Editor works alongside the Editor in terms of adding and manipulating sound in concordance with the film itself. Their jobs will lean toward the technical aspects of sound, syncing, ADR, etc.

This isn’t the only job involved with sound in film however, as the Sound Mixer does the post-production and creative processing involved with the film’s audio; they will work with blending the score into scenes, and specific effects and processing of sound, like a music producer.