Run the same technical checks Audible’s ACX runs against your finished audiobook — free, on your whole book. If anything fails, one click fixes every file and re-verifies it, ready to resubmit.
Create a free account and drop in every chapter at once — the same MP3s you’d hand to ACX.
Every file, every check, measured values against the required spec — failures first, so you see exactly why a book bounces.
£19 per audio-hour of failing audio — clean chapters cost nothing — every broken file corrected, re-analysed and handed back with a passing report.
Ten measurements on every file in your book, then whole-book rules on top. This is the exact list the tool runs — nothing hidden. Here’s what a report looks like:
The fix runs one processing chain and one encode per file — no quality-degrading stacking — then re-analyses its own output. You download from a passing report, not a promise. Files that already pass are left completely untouched.
Every failed submission costs you another review cycle. Upload the exact files ACX bounced, see the reason in plain numbers, fix the whole book in one click and resubmit the same day — instead of waiting on a studio’s calendar.
Run the full report on your finished book before it ever reaches ACX. If everything passes, submit with confidence — the check cost you nothing. If something fails, you found out privately, in minutes.
Yes — sign up, upload your book, read the full report. Up to three books a day. You only pay if you choose the one-click fix, and the price is shown before you commit.
Two things stay human: pauses over 5 seconds are pace edits to your performance, so we flag them with timestamps instead of cutting them; and a genuinely noisy recording (a failing noise floor) is a recording-chain issue — the report shows it honestly rather than pretending processing can un-record it.
Only the audio that failed. The quote counts the failing files — a single broken 30-minute chapter in a 10-hour book prices as 30 minutes (the £25 minimum), not 10 hours. Clean chapters are never processed, never re-encoded and never charged.
No stacking, no repeated re-encodes: each file goes through one processing chain and one encode. Files that already pass are not touched at all.
The report takes a few minutes for a typical book. The fix runs immediately after payment and re-checks itself as it goes — most books are ready to download the same sitting.
The fixer re-runs the same analysis on its own output and shows you the after-report. You download from a green report, not from a claim.
The finished MP3 files you’d submit to ACX — every chapter at once, up to 120 files per book. Your files sit in your private account area and you can clear them any time.
The usual culprits are technical, not performance: RMS loudness outside the −23 to −18 dB window, peaks louder than −3 dB, a noise floor above −60 dB, MP3s encoded under 192 kbps, missing room tone at the head or tail, or chapters that don’t match each other’s format. The free report measures every one of these on every file, failures first, so you can see exactly why your audiobook bounced.
Run the free ACX compliance check on your whole book, then use the one-click fix: it corrects the failing files — loudness, peaks, encoding, sample rate and room tone — in a single processing pass, re-runs the full analysis on its own output, and hands back files with a passing report, ready to resubmit to ACX.
Each file must measure −23 to −18 dB RMS, peak no higher than −3 dB, keep its noise floor at or below −60 dB RMS, be a 192 kbps-or-better CBR MP3 at 44.1 kHz, carry room tone at head and tail, run under 120 minutes, and stay consistent in channel format across the whole book. Those are exactly the numbers this tool checks against.
The full ACX compliance report on your whole book — free, in minutes.
Your full ACX compliance report is free — no card needed.