Mastering Prep

A workflow for preparing your mix for mastering, or for self-mastering with measurement guidance. You’ll compare against references, match to genre targets, and run final quality checks.

When to use this

  • Your mix is finished and you’re preparing to master (or send to a mastering engineer)
  • You’re self-mastering and want objective guidance
  • You want to verify your master is competitive with commercial releases

Workflow Overview

1

Compare to genre profile

See how your mix stacks up against typical loudness, spectrum, and dynamics for your genre

2

A/B against a reference track

Compare your mix to a specific commercial release you admire

3

Get matching recommendations

Phantom suggests specific EQ, loudness, and width adjustments to close the gap

4

Apply processing and verify

Make changes based on recommendations, then measure to confirm improvement

5

Final quality check

Catch any remaining problems before the master goes out

Step 1: Compare to genre profile

Why: Before reaching for a reference track, check how your mix compares to genre norms. This gives you context for whether deviations are intentional artistic choices or unintentional oversights.

Prompt:

Compare my mix to a pop profile — how does it measure up in loudness, spectrum, and dynamics?

Phantom output:

Profile Comparison: mix-final.wav vs Pop profile

Loudness: Yours: -15.1 LUFS Target: -12 to -14 LUFS UNDER Peak: -2.3 dBTP Target: -1.0 dBTP min OK

Spectrum: Low end: +0.4 dB vs target OK Mids: +0.8 dB vs target OK Highs: -2.6 dB vs target (dark)

Dynamics: Range: 8.1 LU Target: 5-8 LU OK (edge) Crest: 10.2 dB Target: 6-10 dB OK (edge)

Stereo: Width: 0.68 Target: 0.6-0.8 OK

Overall match: 74% Issues: 2 (below target loudness, dark top end)

What to look for:

  • “UNDER” on loudness means you’ll need gain + limiting
  • “Dark” spectrum means the high end needs attention (shelf EQ or exciter)
  • Values at the “edge” of target ranges are worth monitoring but not necessarily fixing

Step 2: A/B against a reference track

Why: Genre profiles are averages. A specific reference track you admire gives you a concrete target for the sonic character you want.

Prompt:

Compare my mix at mix-final.wav against reference-track.wav — show me the detailed differences in spectrum, loudness, and width

Phantom output:

Reference Comparison Your file: mix-final.wav Reference: reference-track.wav

Loudness: Yours: -15.1 LUFS Reference: -12.4 LUFS Difference: -2.7 LUFS (yours is quieter)

Spectrum: Band comparison: Sub: -0.3 dB vs ref OK Low: +0.8 dB vs ref (slightly bass-heavy) Low-mid: +1.1 dB vs ref (boxy) High-mid: -0.9 dB vs ref (less forward) High: -2.1 dB vs ref (darker)

Dynamics: Crest: 10.2 dB Reference: 7.1 dB Difference: Yours is more dynamic (+3.1 dB crest)

Stereo: Width: 0.68 Reference: 0.78 Difference: Yours is narrower (-0.10)

Overall similarity: 68%

What to look for:

  • Loudness difference of 2.7 LUFS is significant — the limiter will handle this
  • The reference is brighter (+2.1 dB in highs) and more forward (+0.9 dB high-mid)
  • Reference is wider (0.78 vs 0.68) and more compressed (crest 7.1 vs 10.2)

Step 3: Get matching recommendations

Why: Now that you see the differences, let Phantom suggest specific processing to close the gap. These are starting points — you’ll adjust to taste.

Prompt:

Give me specific EQ, loudness, and width recommendations to match my mix closer to the reference

Phantom output:

Match to Reference: mix-final.wav -> reference-track.wav

Spectral Matching: Suggested EQ curve: +1.8 dB shelf at 10 kHz (add air/brightness) -1.0 dB bell at 350 Hz, Q=1.5 (reduce boxiness) +0.8 dB bell at 4 kHz, Q=1.8 (add presence)

Loudness Matching: Current: -15.1 LUFS Target: -12.4 LUFS Gain needed: +2.7 dB (apply before limiter) Limiter ceiling: -1.0 dBTP recommended

Width Matching: Current: 0.68 Target: 0.78 Suggestion: +15% stereo widening above 2 kHz Keep sub-200 Hz in mono

Confidence: 81%

How to apply:

  1. Add a mastering EQ with the suggested curve (shelves first, then bells)
  2. Add gain before your limiter
  3. Set limiter ceiling to -1.0 dBTP
  4. Apply subtle stereo widening in the upper frequencies
  5. Keep the low end mono (M/S EQ: narrow below 200 Hz)

Pro tip

Apply recommendations at 50-70% of suggested values first. A +1.8 dB shelf at 10 kHz? Start with +1.0 dB and listen. You can always add more, but it’s harder to undo over-processing after your ears adapt.

Step 4: Apply processing and verify

Why: After applying the mastering chain, measure again to confirm you moved in the right direction and didn’t introduce new problems.

You can apply the mastering chain manually in your DAW and export, or use apply_processing to apply it directly:

Prompt:

Apply the recommended mastering chain to mix-final.wav: +1.8 dB shelf at 10 kHz, -1.0 dB at 350 Hz, +0.8 dB at 4 kHz, then +2.7 dB gain, limit to -1.0 dBTP. Save as mastered-v1.wav

apply_processing executes the chain in order and writes the result to a new file. Requires pip install phantom-audio[processing]. Your original stays untouched.

Then verify:

Prompt:

Compare my master at mastered-v1.wav against the reference — did I close the gap?

Phantom output:

Reference Comparison (after mastering) Your file: mastered-v1.wav Reference: reference-track.wav

Loudness: Yours: -12.8 LUFS Reference: -12.4 LUFS Difference: -0.4 LUFS (very close)

Spectrum: Band comparison: Sub: -0.2 dB vs ref OK Low: +0.4 dB vs ref OK Low-mid: +0.3 dB vs ref OK (improved) High-mid: -0.2 dB vs ref OK (improved) High: -0.6 dB vs ref OK (improved, still slightly dark)

Overall similarity: 86% (was 68%)

Decision point: Similarity improved from 68% to 86%. The remaining differences (-0.6 dB in highs) are minor and may be intentional — your mix has a slightly warmer character. Decide if you want to push closer or accept it.

Step 5: Final quality check

Why: Before declaring the master done, run problem detection to catch anything the mastering processing might have introduced — particularly true peak violations and clipping from the limiter.

Prompt:

Run a final quality check on mastered-v1.wav — check for true peak violations, clipping, and any problems introduced by mastering

Phantom output:

Problem Detection: mastered-v1.wav Scanned: mastered-v1.wav (3:42, 44.1kHz/24bit, stereo)

Issues Found: 1

LOW True peak at -0.9 dBTP Two instances at 1:42 and 2:58 Suggestion: Lower limiter ceiling to -1.0 dBTP

No issues: clipping, DC offset, phase, hum, sibilance, mud, harshness, resonances

Overall: PASS (1 minor issue)

Final decision: One minor true peak issue at -0.9 dBTP (just barely over the -1.0 standard). Either lower the limiter ceiling by 0.1 dB, or accept it (some platforms allow up to -0.5 dBTP).

Pro tip

Always run the final check at high sensitivity. Better to catch a marginal true peak issue now than have a streaming platform apply its own limiting to your carefully crafted master.

Quick Reference

  1. Compare my mix to a [genre] profile -- how does it measure up?
  2. Compare my mix against [reference] -- show me the differences
  3. Give me specific EQ, loudness, and width recommendations to match the reference
  4. Apply the recommended mastering chain to [file] and save as [output]
  5. Run a final quality check on [master] -- check for problems

Next Steps