How to Prepare Your Mix for Mastering

You've spent days — maybe weeks — getting your mix right. The balances feel good, the vocal sits where it should, and the low end has weight without mud. Now you need to hand it off to a mastering engineer.

Mastering engineers can enhance dynamics, tighten frequency balance, and optimize loudness. What they can't do is fix problems baked into a poorly prepared mix file. A crushed, over-limited bounce gives them nothing to work with. A mix exported at the wrong format loses quality before they even open the file.

Leave Enough Headroom

Headroom is the space between the loudest peak in your mix and 0 dBFS (the maximum level digital audio can reach before clipping). Your mastering engineer needs this space to apply EQ, compression, and limiting without running into distortion.

Target levels:

• Peak levels: -3 to -6 dBFS (Alexander Wright Mastering recommends peaks around -3 dBFS as a good rule of thumb)
• Average levels (RMS/LUFS): -18 to -12 dBFS

If your mix is already at commercial loudness, the mastering engineer has no room to move. They'll either turn your mix down or try to master an already-squashed signal.

Don't confuse headroom with a quiet mix. A mix with peaks at -6 dBFS can still sound punchy and full. Headroom is technical space for mastering, not a volume reduction.

Handle Your Master Bus Correctly

What's on your master bus when you bounce matters more than most producers realize.

Remove limiters

The single most common mix prep mistake. A limiter on the master bus crushes dynamics and clips transients before the mastering engineer can work with them. Sonarworks puts it plainly: "the mastering engineer will do level adjustments themselves."

If your mix decisions depend on how it sounds with the limiter engaged, send two versions: one with and one without.

Keep subtle mix bus processing (maybe)

Light mix bus compression for "glue" — 1–2 dB of gain reduction — is fine to leave on if you mixed into it. Same for subtle EQ or saturation that's part of your mix character.

Rule of thumb: if removing it changes how your mix feels, leave it on. If it's there to make things louder, take it off.

Remove utility plugins

Bypass metering plugins, spectrum analyzers, and monitoring tools from the master bus before bouncing.

Export at the Right Format and Settings

Your mastering engineer needs the highest-quality file you can provide.

File format

Export as WAV or AIFF — lossless formats that preserve full audio quality. Never send MP3 or any compressed format.

Bit depth

Export at 24-bit or 32-bit float. 32-bit float is ideal because it preserves full dynamic range, including any overshoot above 0 dBFS (Formation Audio). Do not export at 16-bit — that's a CD delivery format, not a mastering working format.

Sample rate

Export at your session's native sample rate. Do not upsample — bouncing a 44.1 kHz session at 96 kHz creates a larger file with interpolated data, not real quality. The mastering engineer will handle sample rate conversion for final deliverables.

Do not normalize

Turn off "normalize" in your DAW's export settings. It adjusts gain after export, changing your carefully set headroom levels.

Do not dither

Dithering applies during bit depth reduction. Since you're sending 24-bit or 32-bit files for further processing, dithering is premature — the mastering engineer applies it as the final step.

Leave Head and Tail Room

Don't trim your bounce right to the first note or right after the last sound.

At the beginning: Leave at least half a second of silence before the first transient.

At the end: Let reverb tails, delay trails, and sustain ring out completely. Add an extra 2–3 seconds of silence after the last audible sound. Cutting tails short creates an audible, unprofessional truncation.

Check Your Mix Before Bouncing

Before you export, run through these quality checks:

Listen in mono

Fold your mix to mono and listen through. If elements disappear, you have phase issues — common with stereo-widened synths, chorus effects, and heavily processed reverbs. Your mastering engineer can't fix phase cancellation after the fact.

Listen on multiple systems

Check on monitors, headphones, earbuds, and your phone. You're listening for problems that only show up on certain systems — bass buildup invisible on headphones might be obvious in the car.

Check for artifacts

Solo each track and listen for clicks, pops, and digital artifacts. Check edit points for audible cuts. These micro-problems get amplified by mastering compression — what's barely noticeable in a busy mix becomes obvious in the master.

Verify fades

If your song fades in or out, bounce with the fade included. Don't rely on the mastering engineer to guess the curve and length you intended.

Stereo Bounce vs. Stem Mastering

Most mastering is done from a single stereo file, but some engineers offer stem mastering as an alternative.

Stereo mastering is the standard — one stereo WAV, the mastering engineer works with the mix as a whole. Faster, cheaper, and appropriate for well-balanced mixes.

Stem mastering means sending 4–8 grouped stereo files (drums, bass, vocals, instruments, effects), giving the engineer more control — they can adjust vocal level relative to instruments, tame a boomy bass without affecting the rest, etc. Costs more, but worth it if your mix balance isn't quite right or you have a known problem area.

How to prepare stems

If you're sending stems:

1. All stems must be the same length — start every stem from bar 1 so they align when stacked.
2. All stems must sum to your stereo mix — this is your error check.
3. Include effects — stems should include their processing (reverb, delay, compression) unless told otherwise.
4. Use the same export settings as your stereo bounce.
5. Name clearly: "Drums.wav," "Bass.wav," "Vocals.wav," "Synths.wav," "FX.wav."

Name Your Files Properly

Use a clear, consistent format:

Artist Name - Song Title - Mix Version.wav

For example:

• Luna Park - Daylight - Mix v3.wav
• Luna Park - Daylight - Mix v3 (No Limiter).wav
• Luna Park - Daylight - Mix v3 STEMS - Drums.wav

If you're sending multiple songs for an album or EP, include the track number:

01 - Luna Park - Daylight - Mix v3.wav
02 - Luna Park - Nightfall - Mix v2.wav

Include Mastering Notes

A short brief helps the mastering engineer understand what you're going for:

• Reference tracks — one or two commercially released songs representing your target sound and loudness. The single most useful thing you can provide.
• Specific concerns — "Low end feels muddy below 80 Hz." "Vocal might be bright around 4 kHz." Be honest.
• Target loudness — a specific LUFS target, or let the ME use standard streaming targets (~-14 LUFS).
• Delivery formats — WAV for digital distribution? DDP for CD? High-res for hi-fi platforms?
• Album sequencing — track order and whether you want gaps or gapless transitions.
• Song metadata — ISRC codes, UPC, and credits to embed in the final files. Having this ready prevents delays in the release process.

The Complete Pre-Mastering Checklist

Before you send your files, run through this list:

Levels and processing:

• Peaks between -3 and -6 dBFS
• Average levels between -18 and -12 dBFS (RMS/LUFS)
• Limiter removed from master bus (or second version without limiter included)
• Only intentional mix bus processing remains (light glue compression, subtle EQ)

Export settings:

• WAV or AIFF format
• 24-bit or 32-bit float
• Native session sample rate (no upsampling)
• Normalize off
• Dither off

Audio quality:

• Mono compatibility checked — no phase cancellation
• No clicks, pops, or digital artifacts
• Reverb and delay tails fully captured
• Head room at start (0.5+ seconds of silence)
• Fades included if applicable

Files and documentation:

• Files named clearly with artist, title, and version
• Reference tracks included with notes
• Mastering brief with concerns and target loudness
• Delivery format requirements specified
• Song metadata (ISRCs, credits) provided
• Track order included for album/EP projects

Key Takeaways

• Leave headroom: peaks at -3 to -6 dBFS, average levels at -18 to -12 dBFS. Don't try to make your mix loud — that's the mastering engineer's job.
• Remove limiters from your master bus before bouncing. If your mix depends on the limiter, send two versions (with and without).
• Export as WAV or AIFF at 24-bit or 32-bit float, at your session's native sample rate. Don't normalize, dither, or upsample.
• Check your mix in mono, on multiple systems, and for artifacts before sending. Problems get amplified by mastering processing.
• Include reference tracks, a brief with your concerns, and clearly named files. Good communication saves revision rounds.