Dubbing mixer
From Tardis Wiki, the free Doctor Who reference
The Dubbing Mixer is part of a post-production team and is responsible for editing together the dialog, music and sound effects to create the final soundtrack for a production. They are responsible for ensuring that the sound in a film or television program is technically correct, and as near to the director's or sound designer's original idea.
The Dubbing Mixer acheives this by performing tasks such as mixing and cross-fading the sound, using the soundtrack that was prepared by the music editor.