In music, a stem is a group of related sounds from a song, mixed together into one audio file. A common set is four stems: vocals, drums, bass, and other instruments. Stems sit between a finished stereo mix and the full multitrack session, so you can change one part, such as the vocals, without touching the rest.
That is why editors use them: to sit music under dialogue, drop the drums for a quiet moment, or build an instrumental version of a song.
Stems, multitracks, and the stereo mix
These three terms describe how much of a song you have separated.
- The stereo mix is the finished song as one file. Every instrument is blended together and you cannot change one without changing the others.
- Multitracks are every individual recording from the session, such as each microphone and each instrument. A full song can have dozens.
- Stems sit in between. Related tracks are grouped and mixed down, so all the drums become one stem and all the vocals become another.
The common stem sets
- 4 stems: vocals, drums, bass, and other. Other holds everything that isn't one of the first three, such as guitars, keys, and synths.
- 6 stems: the same four, with guitar and piano pulled out of other into their own stems.
- Vocals and instrumental: a simple two-way split.
Vocal, drum, bass, and other stems explained
- Vocal stem: the lead vocal and any backing vocals. Lower it to make room for dialogue, or mute it for an instrumental.
- Drum stem: the drum kit and percussion. It carries most of a track's rhythm and energy, so dropping it makes a section feel instantly quieter.
- Bass stem: the bass guitar or synth bass. It holds the low end, which is often what competes with a voice.
- Other stem: everything else, such as guitars, keys, strings, and synths. In a 6-stem set, guitar and piano are split out of this one.
How to use stems in video editing
- Get the stems. Some composers and labels supply them with the track. Otherwise, separate them from the finished song.
- Put each stem on its own audio track in your timeline, starting at the same point so they stay lined up.
- Rebalance under dialogue by lowering the vocal stem, and the other stems if the mix is still busy, instead of turning the whole song down.
- Edit the music to the picture. Bring the drums in on a cut, drop them out for a quieter beat, or strip a track back to bass and keys for a transition.
- Check the result against your dialogue at normal listening level, then export as usual.
Where stems come from
Sometimes a composer or label supplies stems with the track. When they don't, software can estimate them from the finished mix. Separated stems are an estimate, not the original recordings, so a stem can carry faint traces of another part. Results are cleanest on music with clear, distinct parts.
Where that software runs is a separate question, and it matters for client work. See local vs cloud stem separation.
Other uses for stems
Outside video, stems are used to remix a track, to make practice or karaoke versions, and by mixing engineers who send stems to a mastering engineer instead of a single stereo file.
A note on rights
Separating a track does not change who owns it or what you are allowed to do with it. Check the license for any music you use, whether or not you split it into stems.
Getting stems inside your editor
StemForge separates stems and imports them into your project without leaving the editor. See how to separate stems inside Premiere Pro or how to separate stems in DaVinci Resolve Studio, or read the FAQ for what it supports.
