Stem Mastering: Upload Vocals, Bass and Drums Separately

2026-07-19 · Magic Master

Introducing stem mastering — a mode where you upload not a finished stereo mix but its building blocks: vocals, bass, drums, the rest. It's the professional mastering-studio workflow, now one click away.

Why master from stems

When a mastering engineer receives a finished stereo mix, their options are limited: EQ and compression hit everything at once. Stems remove that limit:

vocal buried? — +1.5 dB on the vocal only, without brightening the cymbals;
bass booming? — −3 dB on the bass only, mids untouched;
a sum of stems is more honest than any "re-EQ" of a finished mix.

That's exactly why serious studios ask clients for stems. Now we can too.

How to use it

In the app: upload 2–8 stems in the batch section (magicmaster.pro/app?lang=en, PRO token mastering) and tick "These are stems of one track". We sum them and master the result as a whole — genre preset, target LUFS, full track passport.

Via the API — with per-stem gains:

curl -X POST https://magicmaster.pro/api/v2/master/stems \
  -H "X-API-Key: mm_live_YOUR_KEY" \
  -F "files=@vocals.wav" -F "files=@bass.wav" -F "files=@drums.wav" \
  -F 'gains_db=[1.5, -3, 0]' \
  -F "style=hiphop" -F "target_lufs=-10"

Different sample rates and lengths are aligned automatically, the sum is protected from overload. Technical details — in the API docs.

The honest details

Price: 1 token — it's one master of one track.
Same guarantees: unconditional target LUFS at the end of processing, true peak ≤ −1 dBTP, post-codec check.
Export stems from the same start point (bar 1) — we align lengths but never shift phase.

Try it: magicmaster.pro/app?lang=en — batch section → "These are stems of one track".

Questions and answers

What is stem mastering and why does it matter?

Stems are groups of your mix's tracks (vocals, bass, drums, everything else) exported as separate files. Mastering from stems gives control impossible with a finished stereo mix: raise the vocal by 1.5 dB or pull the bass down 3 dB right at the mastering stage, without going back to the DAW.

How does it work here?

Upload 2–8 stems in the batch section and tick 'These are stems of one track'. We sum them (optionally with per-stem gains via the API), align sample rates and lengths, and run the sum through the full mastering pipeline: genre preset, target LUFS, true peak, track passport.

How much does it cost?

1 token — same as a regular mastering: it is one mastering of one track, just with a more honest input.

Do stems need the same length and sample rate?

No. Different sample rates are resampled to the highest one, shorter stems are padded with silence. Just make sure all stems are exported from the same start point (bar 1).

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