**Stems:**
Stems are like mixed groups of musical elements within a song. They originated a long time ago when music was put on physical media like vinyl or CDs. Back then we made several mixes of a song, such as: the master mix, instrumental mix (only music, no vocals), TV track (full mix without lead vocals for TV performances), and vocal-only mix. These were all stereo mixes with various components.
For example, combining the instrumental mix with the vocal-only mix allowed us to recreate the master mix but adjust the balance between vocals and instruments later if needed. Over time labels wanted more control, so they asked for separate stereo submixes (stems) of various components like drums, bass, guitars, and more. This allowed for post-production adjustments and created new revenue opportunities.
**Multitracks:**
Multitracks are individual recordings of each instrument or voice in a song. Think of them as separate tracks for drums, guitars, vocals, and so on. Each of these tracks might have processing (like EQ or effects) applied to them, depending on how they were recorded.
When you send multitracks to a mix engineer, you're giving them the original, unprocessed recordings. This is crucial because it allows the mix engineer to have full control over the sound and make the song sound its best.
**Important Notes:**
Before sending multitracks to a mix engineer, remember that it's not their job to decide how these tracks should be combined or edited. For instance, don't send them multiple tracks of the same instrument or vocals expecting them to figure it out. The producer or artist should handle that part.
In addition, you will always want to send all files as .wav - never as .mp3. Reason being that .mp3 files are so much smaller as a result of literally stripping away a great deal of information. It may sound the same in a small speaker but rest assured they are not the same and once you’ve downgraded to an .mp3 that information is lost forever. In sum: never send your producer .mp3 files!
In sum: stems are mixed groups of musical elements, while multitracks are the raw, unprocessed recordings of individual instruments or vocals. Providing multitracks to a mix engineer gives them the flexibility to work their magic and create a great-sounding mix.
