What is a stem in music, and what is a vocal stem?

Short answer

A stem is a group of related tracks mixed into one audio file, such as all the drums, all the backing vocals or the lead vocal. A vocal stem contains only the singing. Producers export stems from the original session; AI separation estimates them from a finished mix, so expect some leakage.

Last reviewed: 2026-10-10

Explanation

A multitrack session can hold dozens of tracks: separate microphones on each drum, several guitar takes, harmonies. Grouping them into a few submixes, such as drums, bass, vocals and everything else, gives stems that are easier to share, remix or master.

When the session is not available, source-separation software can estimate stems from the finished stereo file. The open Demucs models, for example, separate drums, bass and vocals from the rest of the accompaniment, and Logic Pro for iPad's Stem Splitter extracts vocals, drums, bass, guitar, piano and other parts.

Estimated stems are not identical to session stems. Reverb, backing vocals and instruments that share frequencies with the voice can leak between stems.

Stems compared with related terms
Term	What it contains	Typical origin
Multitrack	Every recorded track separately	Studio session
Stem	A grouped submix, e.g. drums or vocals	Session export or AI separation
Vocal stem	Lead (and sometimes backing) vocals only	Session export or AI separation
Instrumental / MR	Everything except the lead vocal	Official release or vocal removal

Frequently asked questions

How many stems does a song usually have?

There is no fixed number. Four (vocals, drums, bass, other) is a common separation set; some tools add guitar, piano and more.

Is a vocal stem the same as an acapella?

Mostly. Both are vocals without accompaniment, but an official acapella may be edited or processed differently from a raw session stem.

Can I get stems from an MP3?

Yes, AI separation can estimate them from an MP3, but compression and dense mixes make leakage more likely.

Does MR Maker export separate stems?

No. MR Maker delivers a vocal-reduced accompaniment file for singing, not separate drum, bass or vocal stems.

Make a backing track from your own file

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Sources

Each source was opened and checked on the date shown.

Stem (audio) — Wikipedia (checked 2026-10-10)
Demucs: music source separation (README) — Meta Research on GitHub (checked 2026-10-10)
Extract vocal and instrumental stems with Stem Splitter in Logic Pro for iPad — Apple Support (checked 2026-10-10)