Raw recording in. Submission-ready out.
Upload your audiobook chapter. Greenlit removes clicks, pops, and mouth noise, masters it to ACX spec — loudness, peaks, noise floor, format — and tells you exactly what it fixed.
Free diagnostic, no account · 8-point ACX report · Results in under 60s · Built by a Big 5 audiobook QC professional with years in the field
chapter-01.wav
2 issues found · ACX would reject this file
- Noise Floor−54.2 dB · req. < −60 dB
Room tone is too loud. ACX rejects files where background silence exceeds −60 dB — listeners will hear the hiss.
- True Peak−1.8 dBFS · req. < −3 dBFS
Just over ACX's ceiling. Won't sound distorted, but the automated system will reject it.
✓7 checks passed (RMS, sample rate, bitrate, format, channels, headroom, artifact scan)
Drop your file here · · WAV · AIFF · MP3 · M4A · Max 200 MB · No account required
Scope of work
You bring the performance. We handle the rest.
Greenlit isn't just a checker. It's built on years of professional audiobook QC at the major publisher level — the same compliance criteria used before a file ships to retailers. Upload your finished recording and get back a clean, submission-ready file with a full report showing exactly what changed.
Cleanup powered by Dolby.io · mastered to ACX targets with FFmpeg
You bring
- A clean recording
- Consistent narration
- Opening & closing credits
- One chapter per file
We handle
AI cleanup
- Background noise reduction
- Low-frequency rumble removal
- Click & pop removal
- Plosive reduction (P & B bursts)
- Sibilance / de-essing (harsh S sounds)
- Mouth-noise cleanup
Mastering & format
- Loudness normalization (RMS)
- True peak limiting
- Head & tail silence padding
- Compliant CBR MP3 export
- Full 8-point compliance report
Three steps. Zero audio knowledge.
Upload your chapter
Drop in your finished recording — WAV, MP3, FLAC, or AIFF. No account needed for a free diagnostic. One chapter at a time, up to 120 minutes.
We run the pipeline
An AI enhancement pass removes clicks, pops, mouth noise, and hiss. Then mastering normalizes loudness, limits peaks, pads silence, and exports a compliant MP3 — measured before and after.
Download master + report
Get your ACX-compliant MP3 plus a full report showing every measured value, with a clear pass or fail on each spec.
The 8-point check
Every spec ACX checks — measured in seconds.
RMS
Loudness sits right in the −18 to −23 dBFS sweet spot ACX wants.
Free analysis · No account required
See exactly what ACX would reject — before you submit.
Upload any file and get a plain-language breakdown of every spec check. No audio engineering knowledge required.
RMS Loudness
−18.3
dBFS · in spec
Loudness sits right in the −18 to −23 dBFS sweet spot ACX requires.
True Peak
−1.8
dBFS · we lower it
A touch over the −3 dBFS ceiling. ACX auto-rejects this — we fix it transparently.
Noise Floor
−54.2
dB · too loud
Room tone is too loud. Needs to be below −60 dB — background hiss will fail human QC.
Analysis is always free. Processing starts at $12 / finished hour.
Run a free analysis →Why this exists
Built by someone who does this professionally.
I've worked in audio post production at a multiple Grammy Award-winning studio — one of the world's largest independent audiobook producers, working with the Big 5 publishers. Part of that work is QC: checking that final masters meet the technical and quality standards retailers require before distribution. Over the years, that's added up to more than 200,000 files.
After that many, the pattern is hard to miss: most rejections aren't about performance. They're about specs. Loudness a few dB off. A noise floor just over the limit. A peak that triggers an auto-reject. Problems a specialist can spot in thirty seconds.
Indie narrators were paying engineers $700 to fix what amounts to a calibration problem. Greenlit automates the check — and the fix. Same standard the major studios use. A fraction of the cost. Results in minutes.
How it compares
Studio-grade mastering, without the studio bill.
| Mastering method | Estimated cost | Time | Trade-offs |
|---|---|---|---|
| Human mastering engineer | $700–$1,200 | 3–7 days | Expensive, slow, must share files |
| Professional QC specialist | $200–$500 | 2–5 days | What Big 5 publishers hire for final sign-off |
| Fiverr freelancer | $100–$300 | 1–3 days | Variable quality, IP exposure |
| Manual in Audacity | Free | 2–10+ hours | Steep learning curve, high rejection risk |
| Greenlit Audio | from $4.98 / hr | ~2 minutes | Built by someone who does this professionally at the Big 5 level · AI cleanup + mastering + report |
87%
lower cost than studio mastering
8
ACX spec checks on every file
<2 min
average processing time per chapter
Pricing
Buy credits. Use them on any book. They never expire.
Diagnostic checks are always free — no account required. Pay only when you process.
Novella
15 finished hours
$5.93 / hr
Short books and novellas. Covers roughly three 5-hour projects.
- 15 finished hours included
- Credits never expire
- Full cleanup + ACX mastering
- Plain-language QC report
- Submission-ready MP3 (192 kbps CBR)
Novel
30 finished hours
$5.30 / hr
Standard novels. Most full-length audiobooks run 8–15 finished hours.
- 30 finished hours included
- Credits never expire
- Full cleanup + ACX mastering
- Plain-language QC report
- Submission-ready MP3 (192 kbps CBR)
Omnibus
50 finished hours
$4.98 / hr
Series, anthologies, or narrators working across multiple books.
- 50 finished hours included
- Credits never expire
- Full cleanup + ACX mastering
- Plain-language QC report
- Submission-ready MP3 (192 kbps CBR)
Not ready to commit to a pack? Process single files at $12 / finished hour — no purchase minimum.
FAQ
Common questions.
Does Greenlit remove clicks, pops, or mouth noise?
Yes — this is one of the biggest differences between Greenlit and simpler mastering tools. Your file goes through an AI enhancement pass that reduces background noise, removes clicks and pops, and cleans up mouth noise before mastering. You still want a clean take — it's not a substitute for good recording — but the minor artifacts that cause rejections or distract listeners get cleaned up automatically.
Will my file definitely pass ACX after processing?
Greenlit guarantees the measurable technical specs: loudness, true peak, noise floor, sample rate, channel count, bit rate, and silence. ACX also runs a human quality review — a real person listens for things like room echo, inconsistent tone, and manuscript accuracy. That’s the part of this job I’ve done professionally for years across more than 200,000 files. The honest truth: no tool can fix a bad take. But if your recording is solid, Greenlit handles everything the automated system checks.
Does it work for platforms besides ACX?
Yes. The same technical spec that passes ACX — loudness targets, noise floor, sample rate, and format — is what Findaway, Google Play, Kobo, and Apple Books all require. Get your file right once and it’s ready everywhere.
What is a "finished hour" and how is it billed?
A finished hour (PFH) is the duration of your processed audio, rounded to the nearest 0.1 hours. A 45-minute chapter is 0.8 finished hours. Credits come in packs — Novella (15 hrs · $89), Novel (30 hrs · $159), or Omnibus (50 hrs · $249) — and never expire, so leftover hours roll over to your next book. Need just one file done? Process at $12 / hr with no pack required.
Do I need a subscription to check my file?
No. The diagnostic check — a full 8-point ACX report with actual measured values — is free, with no account required. You only pay when you want Greenlit to process and fix the file.
Do I need a DAW to use Greenlit?
Not for mastering — that’s what Greenlit replaces. You’ll still need a way to record and edit your narration (fix mistakes, add credits). Once your edited recording is ready, Greenlit handles the mastering step.
Ready to get your audio greenlit?
No account. No card. Upload a chapter and see your ACX compliance report in under 60 seconds.
Run a free ACX check