Music industry terminology

Stems

Also called: Stem files, Track stems, Music stems

Stems are individual instrument or instrument-group recordings exported separately from the same song. A typical stem set includes drums, bass, vocals, and "other" (everything else). More detailed stem sets break out guitars, keys, synths, percussion, and lead vocal vs background vocals as separate files.

Stems exist so the song can be re-mixed or re-balanced in a different context than the original master. A music editor cutting a TV scene might need to drop the vocal under dialogue. A trailer house might need to swap the percussion. A DJ might need to remix. Stems make all of that possible without anyone calling you at 1am asking you to bounce a new version.

Why it matters

For sync licensing, stems are often the difference between getting the placement and not getting it. A supervisor working a tight cue might love your song but need to lose the vocals for a 10-second moment. If you sent stems, they cut the vocals and use the placement. If you only sent the mixed master, they pass and license a different track. Same brief, different outcome, all because of one folder of WAVs.

For working composers, shipping stems on every track is a competitive advantage. For producers and engineers, modern AI tools can also separate stems from a finished mix when the original session is unavailable, though purpose-recorded stems are always cleaner than separated stems.

How it works

Traditional stems come from the multi-track session: the engineer mutes everything except one instrument group, exports the audio with all the same processing applied as in the final mix, and saves the file. They repeat for each group. The result is several WAV files that, when summed, reconstruct the master mix exactly.

A standard stem split for sync licensing is four files: drums, bass, vocals (or melody for instrumental), and other (everything else). A more detailed split for production use might be 12 to 24 stems: kick, snare, percussion, bass, rhythm guitars, lead guitar, piano, pad, lead synth, lead vocal, background vocals, etc.

When the original session is not available, AI stem separation tools (Demucs, Spleeter, RX) can extract stems from a finished mix. The quality varies by source material. Modern AI models produce usable four-stem splits from most studio recordings, which is a small miracle for anyone who lost a hard drive in 2014.

Examples

A composer ships a sync placement with 12 stem files. The trailer house uses the no-vocal version under the dialogue, then drops the percussion stem under the drop in the trailer's climax for added impact. One delivery, two creative wins.
A library track is delivered with a 4-stem set (drums, bass, vocals, other) plus the full mix and the instrumental. The supervisor uses the instrumental for an ad and the drums-only stem as a hit under a transition.
A producer needs stems from a finished song where the original session is lost forever, presumably to an external drive that will not mount. They run AI stem separation, get usable 4-stem files, and use them in the new project. The quality is good enough for the placement but not as clean as session-exported stems would have been.

Common mistakes

●Shipping stems without the same processing as the master. If your stems sound dry and the master is heavily compressed and EQ'd, summing the stems will not reconstruct the master and the supervisor will get confused, suspicious, or both.
●Forgetting reverb tails. Stem boundaries should include the natural decay of any reverb or delay applied to that instrument, not just the dry signal. A reverb tail clipped mid-decay is the audio equivalent of a sentence cut off mid-word.
●Mislabeling files. "Stem1.wav" tells nobody what they are looking at. "Track Name (Drums Stem).wav" is the standard. Stem1 through Stem12 in a folder is somebody else's problem now.
●Confusing stems with multitracks. A multitrack session has every microphone and overdub as separate tracks (often 60+ files per song). Stems are a small group of pre-balanced submixes (usually 4 to 12 files). Sync clients want stems. Nobody wants your 84-file multitrack zip.

How DropCue handles this

DropCue includes AI stem separation on every paid plan. Click a track, get four stems (drums, bass, vocals, other) in about 60 seconds. Choose WAV (uncompressed) or MP3 (320 kbps). Pro plans include 5 free stem credits per month with additional packs available.