What music stems are and how to use them

A stem is one part of a song saved as its own audio file: the drums on their own, the bass on its own, the guitar, the keys, and everything else. Each stem runs the full length of the song and starts at the same moment as the others, so if you play them all together you hear the finished mix. Having the stems means you can turn one part down, mute it, replace it or move it, without touching the rest.

Stems, multitracks and stem splitters

The words get used loosely, so it helps to separate three things.

Multitracks are the individual recordings from a session: every microphone and every instrument on its own track, sometimes forty or more. They are what an engineer mixes from.

Stems are fewer, grouped parts: usually four to eight, such as drums, bass, guitar, keys and vocals. A mix engineer bounces them from the multitracks so someone else can rebalance the song without a full session.

A stem splitter works the other way round. It takes a finished stereo mix and tries to pull the parts back out of it. That is useful when a mix is all you have, but it is an estimate: some of the hi-hat stays in the vocal, some of the bass leaks into the drums, and the parts no longer add up exactly to the song.

The cleanest stems are the ones made with the song. When each part exists on its own from the start, there is nothing to separate, and the parts sum to the mix exactly.

What people use stems for

Under a voice. A track that works on its own can crowd a voiceover. With stems you drop the drums and keys while someone is talking and bring them back for the intro and the outro. Podcast beds and YouTube edits do this constantly: see background music for YouTube videos.

In a game. Games use stems to make music respond to what the player is doing. A dungeon can loop on keys and a low pad while the player explores, then bring in bass and drums the moment enemies appear, all from one track, so the music never stops to change. Keep the tempo and key the same across a level and the cues join cleanly. Two places to start: dungeon music for the quiet layer, and boss battle music for a theme you can raise phase by phase.

In a mix or a remix. Producers use stems to rebalance a song, replace one part with their own, or take the drums from one track and the bass from another. A remix contest is usually just a set of stems.

To fix one thing. If the guitar is too busy, mute it. If the bassline is wrong, swap it. With stems, a song that is nearly right does not have to be thrown away.

How to get stems for a song

There are three ways, and the right one depends on where the song comes from.

1. Record or bounce them yourself. If you made the song in a session, export each group of tracks as its own file, all starting at zero and all the same length.
2. Split a finished mix. If all you have is a stereo file, a stem splitter gives you usable parts. Expect some bleed between them, especially between drums and bass.
3. Make a song that comes as stems. Daydream's music generator makes every song as five stems at the same time: drums, bass, guitar, keys and other. They are lined up sample for sample and add up to the mix exactly, because nothing was pulled apart afterwards. You can also make one part again, say the drums, and the other four stay exactly as they were. Make a song with stems from a description.

If you are comparing tools that give you stems, we keep a dated list in which AI music generators give you stems.

What to check before you use a set of stems

• Same length and start. Every stem should begin at the same moment and run the same length, or they drift when you line them up.
• They sum to the mix. Play them all at full level; it should sound like the finished song. If it sounds thin or doubled, something is missing or repeated.
• Format. WAV or FLAC keeps every sample. MP3 stems are smaller but lose detail and can add a short gap at the start, which matters for loops.
• Rights. Stems carry the same licence as the song. If you can use the song commercially, you can use its stems the same way; if not, the stems don't change that.

Questions

Are stems the same as multitracks? No. Multitracks are every individual recording from a session. Stems are a few grouped parts, such as drums, bass and keys, made so the song can be rebalanced without the whole session.

Can I get stems from a song I didn't make? You can split a finished mix into parts with a stem splitter, but the parts will bleed into each other, and the song's licence still applies to whatever you do with them. Splitting a track doesn't give you the right to use it.

What format are stems? Usually WAV or FLAC at the song's sample rate. Daydream's stems download as FLAC, 16-bit and 48 kHz, which most audio tools and game engines open.

Do stems cost extra on Daydream? No. Stems come with every song on every plan. A free account gets 3 stem downloads a month and 5 free songs; any credit pack, from $3, makes stem downloads unlimited. Everything is instrumental and royalty-free for commercial use.