Dedicated audio channel containing only music elements, allowing independent editing and processing of the film score in post-production.
Technical Details
Music stems are delivered as standard 24-bit/48kHz files in WAV or AIFF format, typically encompassing 5.1 or 7.1 surround configurations. For more complex productions, separate sub-stems are created for orchestra (strings, brass, percussion), electronic elements, and vocals. The stems are usually mastered with -20dBFS headroom to ensure sufficient dynamic range for the final mix. Modern Digital Audio Workstations (DAWs) like Pro Tools or Nuendo can process up to 32 parallel stem tracks simultaneously.
History & Development
The systematic use of music stems became established from 1977 with the introduction of the Dolby Stereo system and George Lucas' "Star Wars," where John Williams' orchestral recordings were first processed as separate 6-track stems for the cinema mix. The transition to digital post-production in the 1990s enabled lossless archiving and arbitrary recombination of stems. Since 2010, music stems have also been produced in object-based formats like Dolby Atmos, which can manage up to 128 individual audio objects.
Practical Application in Film
Christopher Nolan's "Inception" (2010) utilized 14 separate music stems from Hans Zimmer, including isolated brass stabs and string crescendos, to acoustically differentiate the dream levels. In action sequences, music stems are often cut and rearranged in 2-4 second segments to align with the cutting rhythm and picture editing. Music stems allow for temporary reduction of music during ADR (Automated Dialogue Replacement) sessions without affecting dialogue and sound effects.
Comparison & Alternatives
Unlike a full soundtrack mix, music stems do not contain other audio elements and differ from individual instrument tracks by having already undergone internal mixing. Dialogue stems and effects stems, along with music stems, form the standard trio for the main mix (pre-mix). Layback procedures use the original multitrack recordings but require access to the complete studio mix and are less flexible in post-production.