What to send a mixing engineer: a stems checklist

Why the files you send matter

A mixing engineer rebuilds your song inside their own session. If files are missing, out of sync or already squashed by a limiter, the first part of the job becomes fixing problems instead of making decisions about how the song should sound. Clean, clearly labelled files let the mix start from where your demo left off.

It also helps to be clear about two words that people often mix up. Multitracks are the individual tracks of a session: the kick, the snare, each vocal take, each synth. Stems are grouped submixes, such as all drums on one stereo file or all backing vocals on another. Many people say "stems" for both. For mixing, engineers usually want individual tracks, because grouped stems limit what they can change.

The stems checklist

Go through this list before you export. Most DAWs have a batch export option that handles several points at once.

• Format: uncompressed WAV or AIFF. Do not send MP3 or other compressed formats as mix files.
• Bit depth: 24-bit or 32-bit float.
• Sample rate: the same rate your session uses. Do not convert it on export.
• Same start point: every file starts at the same position, such as the very start of the session or bar 1, and runs to the end of the song, including any silence, so everything lines up when imported.
• Consolidated tracks: one continuous file per track, with edits, comps and crossfades rendered in, rather than lots of small regions.
• Mono and stereo: mono sources such as a single vocal or a kick exported as mono, stereo sources as stereo.
• Clear names: numbered, descriptive file names such as 01_Kick or 14_LeadVox, not "Audio 14".
• Tempo and key: written in a text file or in the folder name.
• Virtual instruments: rendered to audio, since the engineer may not have the same plugins. MIDI files are a useful extra.

Headroom and the master bus

Turn off everything on your master bus before you export: limiters, clippers, bus compressors and any mastering chain. These processors react to the whole mix, so leaving them on bakes their behaviour into every file and takes the decision away from the engineer.

Then check that no individual track clips. If a channel meter hits the top, lower that track's fader or clip gain and export again. Turn off any normalise option in the export window, because it changes the level of each file on its own and breaks the balance between them. The aim is simply that every peak sits comfortably below 0 dBFS. If your engineer gives you a target level, use theirs.

Effects: dry, printed or both

Some processing is part of the sound, and some is just part of your rough balance. A distorted synth, an amp simulator or a creative vocal chain that defines the track is usually best printed into the file. Plain reverbs and delays can be left for the engineer.

For vocals, a common approach is to send the dry vocal as the main file and a second version with your effects printed as a reference. You can also export your reverb and delay returns as separate files so the engineer can keep them or rebuild them. If hard pitch correction is part of the style, as it often is in hyperpop, print the tuned vocal and include the untuned one too. If a part pumps because of sidechain compression, either print it or say so in your notes.

Reference tracks and mix notes

Your rough mix is the most useful reference you can send. It shows your intended balance, even if it does not sound finished. Export it with your master bus processing left on, so the engineer hears exactly what you have been listening to.

Add two or three released songs that are close to the sound you want, with a line on what you like about each, for example the vocal tone on one and the low end on another. Then write a short note that covers:

• What you love in your rough mix and want kept.
• What bothers you, with timestamps where possible.
• Any parts that are optional, muted on purpose or only meant for one section.
• The versions you will need at the end, such as a main mix, an instrumental, a clean version or an a cappella.

A final check before you send

Open a new, empty session, import every file at the very start and play it back with all faders at their default level. It should sound like your rough mix without the master bus processing. If anything is out of time, missing or distorted, fix it now.

Look for the parts that are easy to forget: vocal doubles, ad-libs, risers, one-off effects and anything on a muted track. Put everything in one folder with the rough mix, the references and your notes, compress it into a single archive and share it through a cloud link.

How onyr1x can help

onyr1x is a music producer based in Almada, Portugal, across the river from Lisbon, working in cinematic hyperpop, art-pop and K-pop-leaning production. Alongside custom production and finishing songs, onyr1x offers mixing and mastering, remotely or in studio sessions in Almada.

If you are not sure your files are ready, send what you have and ask. onyr1x replies personally and quotes each project on request.