Understand the difference between audiobook editing, mastering and proofing, what each stage does, and where they fit in production.
Three different stages. Three different jobs. Most narrators confuse them — or do them in the wrong order. Here's exactly what each one does and how to nail all three.
Learn the Difference 3 stagesEvery audiobook goes through Edit firstAlways — order matters -60 dBACX noise floor target Free toolsAudacity handles all 3Audiobook Editing vs Mastering vs Proofing
Editing, proofing and mastering solve different problems. Treating them as one service can create gaps in quality control and make quotes difficult to compare.
For numbers specific to your project, use the Production Budget Planner.
The 3 Post-Production Stages
Each stage has a specific job. Skipping or reordering them creates more work, not less.
Stage 1Editing
Removing performance errors from the raw recording. Outtakes, misreads, mouth noise, coughs, long pauses, and breath sounds all get cut or cleaned in this stage.
🎯 Done on the raw recording Stage 2Proofing
Listening critically to the edited audio while following the manuscript word for word. Catches errors missed in editing — wrong words, inconsistent accents, unnatural gaps.
🔍 Done after editing, before mastering Stage 3Mastering
The final technical polish — noise reduction, compression, normalisation, and peak limiting to ensure the file meets ACX loudness and technical specifications for distribution.
✅ Done last — alwaysThe Post-Production Flow
The order is non-negotiable. Mastering before proofing means re-mastering after every fix. Proofing before editing means listening to unclean audio.
Raw Recording
Unedited chapters
1EDITING
Remove errors, noise, outtakes & breath
2PROOFING
Verify against manuscript, catch missed issues
3MASTERING
Polish levels, hit ACX specs, export
ACX Upload
Distribution-ready
Stage 1 — Editing
Remove everything that doesn't belong in the final listening experience
What Editing Removes
- Outtakes and false starts ("Let me try that again...")
- Misread words or mispronounced names
- Loud mouth clicks, lip smacks, and saliva sounds
- Coughs, sneezes, and throat clears
- Excessive breath sounds between sentences
- Background intrusions (phone buzz, traffic spike)
- Overly long pauses between paragraphs
- Paper rustling or studio chair squeaks
How Editing Is Done
The editor listens through the raw recording — either following a script or listening blind — and makes cuts on a waveform editor. Good editing preserves natural breathing rhythms and doesn't make narration sound robotic.
- DAW tools used: Audacity, Reaper, Adobe Audition
- Technique: Cut and crossfade at zero-crossing points
- Room tone: Use silence from the same session to fill gaps
- Time required: Roughly 2–4× real-time per finished hour
Stage 2 — Proofing
The quality control pass — listen critically, follow the manuscript, and catch everything editing missed
What Proofing Catches
- Wrong words or skipped lines not caught in editing
- Outtakes that were accidentally kept in the file
- Inconsistent character accents or vocal shifts mid-chapter
- Unnatural pacing — rushing or dragging in key sections
- Quiet gaps where room tone is missing after an edit cut
- Incorrect character name pronunciations
- Subtle background noises missed on first pass
- Emotional inconsistency between chapters
How Proofing Is Done
The proofer listens to the edited audio on headphones while reading the manuscript simultaneously. Any issue found is logged with a timestamp and description, then sent back to the narrator for a pick-up (re-record of just that line).
- Tool: Headphones — never speakers for proofing
- Speed: Proof at normal speed — 1x only
- Log format: Timestamp + chapter + issue description
- Who does it: Narrator, author, or hired proofer
Stage 3 — Mastering
The final technical processing that makes your audio sound polished and meet every ACX specification
The 4-Step Mastering Chain
- 1. Noise Reduction: Remove background hiss, hum, and room noise using a noise profile captured from a silent room-tone sample
- 2. EQ / Low-Cut Filter: High-pass filter at 80Hz removes low-frequency rumble without affecting vocal warmth
- 3. Compression: Reduce dynamic range so loud and quiet passages are more consistent — smoother listening experience
- 4. Normalisation + Limiter: Set RMS to -18 to -23 dB and peak ceiling at -3 dBFS to meet ACX specs exactly
ACX Mastering Targets
Every file must hit all four of these specifications before upload to ACX, Apple Books, or any major audiobook platform:
- Noise floor: -60 dB or lower
- Peak level: -3 dBFS maximum
- RMS loudness: Between -18 and -23 dB
- Room tone buffer: 0.5–1 second at start and end
- File format: MP3, 192 kbps CBR, 44.1 kHz
- Check tool: ACX Check plugin (free for Audacity)
Best Tools for Each Stage
You don't need different software for each stage — one good DAW handles all three. Here's what professionals use.
| Tool | Editing | Proofing | Mastering | Cost | Best For |
|---|---|---|---|---|---|
| Audacity | ✅ Excellent | ✅ Good | ✅ Excellent | Free | Beginners |
| Reaper | ✅ Excellent | ✅ Excellent | ✅ Excellent | ~$60 | Professionals |
| Adobe Audition | ✅ Excellent | ✅ Good | ✅ Excellent | ~$55/mo | Studios |
| GarageBand | ✅ Good | ✅ Good | ✅ Good | Free (Mac) | Mac Starters |
| ACX Check Plugin | ❌ N/A | ❌ N/A | ✅ Essential | Free | ACX Compliance |
| iZotope RX | ✅ Pro-Level | ❌ N/A | ✅ Pro-Level | $399+ | Advanced Repair |
DIY vs. Hiring a Post-Production Engineer
Both paths are valid. The right choice depends on your time, budget, and how steep your learning curve feels.
Do It Yourself
Cost: Free to ~$60 (Audacity or Reaper) Full creative control over pacing and feel Skills apply to every future project — builds long-term value No turnaround time waiting on someone else Takes 2–4 hours per finished hour of audio to edit Learning curve for DAW and ACX mastering chain Risk of missing issues without a trained earHire a Post-Production Engineer
Cost: ~$50–$150 per finished hour (editing + mastering) Professional-quality results from day one Saves 4–8 hours of work per book chapter Proofer catches issues a narrator can't hear in their own work Significant cost — adds up quickly on a 10-hour book Turnaround time of 4–20 business days per project Requires finding and vetting a trusted engineerComplete Post-Production Workflow
From raw chapter file to uploaded, distribution-ready audiobook — four clear steps in the right order.
1Edit the Raw Audio
Open each chapter in your DAW. Remove outtakes, mouth noise, coughs, and excessive pauses. Use crossfades at every cut point. Save the edited file before moving on.
2Proof Against the Manuscript
Put on closed-back headphones. Play the edited audio while reading along with the manuscript. Log every issue with a timestamp. Re-record pick-ups, drop them in, and re-check.
3Master for ACX Specs
Apply the mastering chain: noise reduction → low-cut EQ → compression → limiter. Run ACX Check on the output. Adjust until all four specs pass: noise floor, peak, RMS, room tone.
4Export and Upload
Export as MP3, 192 kbps CBR, mono, 44.1 kHz. Confirm 0.5 seconds of room tone at start and end of every file. Upload chapter files to ACX or your platform of choice.
Frequently Asked Questions
What is the difference between audiobook editing and mastering? Editing removes performance errors — outtakes, misreads, mouth noise, long pauses, and coughs. Mastering is the final technical polish — noise reduction, compression, normalisation, and ensuring the file meets ACX loudness and peak specifications. Editing always comes first; mastering is always last. Doing them in the wrong order means redoing work. What is audiobook proofing and when does it happen? Proofing (also called QC or quality control) is the process of listening to the edited audio critically while following the manuscript word for word. It catches errors missed in editing: wrong words, missed outtakes, inconsistent accents, unnatural pacing, and quiet gaps. Proofing happens after editing and before mastering — never at the end after mastering is complete. What is the correct order of audiobook post-production? The correct and only recommended order is: (1) Editing — remove errors and clean performance, (2) Proofing — verify against manuscript and catch missed issues, (3) Mastering — apply noise reduction, compression, normalisation, and hit all ACX technical specs. Never master before proofing — any pick-up re-records after mastering require re-running the entire mastering chain. Do I need to hire someone for audiobook mastering? No. With Audacity (free) and the ACX Check plugin (also free), narrators can master their own audiobooks to full ACX compliance. The four-step mastering chain is: noise reduction, EQ low-cut, compression, and normalisation/limiting to hit RMS -18 to -23 dB and peak -3 dBFS. The free ACX Check plugin verifies compliance before every upload. Can one person do all three stages — editing, proofing, and mastering? Yes — and most self-narrating authors do. However, proofing your own work is the hardest stage to do well because your brain auto-corrects mistakes it already knows are there. Many narrators handle editing and mastering themselves but hire a separate proofer for the QC pass. This catches the errors you're blind to in your own recording. How long does audiobook post-production take per finished hour? Editing takes approximately 2–4 hours of work per finished hour of audio. Proofing takes 1–1.5 hours per finished hour (real-time listening plus logging). Mastering takes 20–40 minutes per chapter once you have a reliable processing chain saved as a preset. A 10-hour audiobook typically requires 30–55 hours of total post-production work from a single narrator.Ready to Post-Produce Your First Chapter?
Follow the three-stage workflow above — edit, proof, then master. Get the ACX Check plugin, run it on your first file, and you'll be upload-ready in under an hour.
Start with EditingHow to Apply This in Practice
Start with the variable you can measure most reliably. For audiobook projects that may be word count, finished hours, PFH rate, production budget or expected royalty income. For listening topics, it is usually total runtime, playback speed and available listening time.
Keep assumptions separate from confirmed numbers. Platform terms, royalty structures, pricing rules and distribution options can change, so verify current provider documentation before making a financial or contractual decision.
Use the related calculator for the math, then return to this guide for the trade-offs that the calculation cannot decide by itself.