What are audio stems and how are they different from tracks?

The short answer

A stem is a grouped audio part such as vocals or drums. In a recording session, stems may be exported from several original tracks. A stem splitter instead estimates groups from a finished mix, so its output can contain sounds that belong to another group.

Try this workflow

1. Upload a song to Stem Splitter.
2. Preview the four groups: Vocals, Drums, Bass and Other.
3. Solo each part to understand what the model has assigned to it.

What to check before you finish

Treat the outputs as useful estimates for practice and editing. They are not the original multitrack session. A vocal stem may include effects, and Other can contain several different instruments playing together.

A practical example

A drum stem might contain kick, snare, hi-hat and room sound together. Muting that group removes the model's estimate of the kit, not separate microphone channels. If you need only the snare, the four-stem output cannot provide that control. Use the group for practice or balance changes that suit its limitations.

More questions

Does one stem equal one instrument?

Not necessarily. A drum stem can contain the whole drum kit, and Other can include guitar, piano, strings and synths.

Are stems always the same length?

Matching exports from one SurStudio split use the same timeline. Keep that set together so another editor can align the parts without guessing offsets.