For audiobook studios and narrators
Audiobook proofreading, without the busywork.
Secondpass checks the narration against your manuscript, flags the words that don't match, and turns the ones you confirm into a pickup sheet.
Priced per finished hour of audio. No subscription.
As the ship rose gracefully above the city, Zuppner, who was at the controls, could scarce restrain his enthusiasm.
…the ship rose gracefully over the city zeupner who…
Not a mockup. These are five real narration errors Secondpass flagged in a public-domain LibriVox recording of Tarzan at the Earth's Core, with the original audio. Play a sentence, keep or dismiss, then open the pickup sheet.
How it works
From raw chapters to a pickup sheet in four steps.
- manuscript.pdf01_Chapter_1.wav02_Chapter_2.wav1
Upload
Add your audiobook chapters and the source manuscript. Drop in a whole folder; big files resume if the connection drops.
- Ch 1Ch 2Ch 32
Analyze
Secondpass transcribes the narration, lines it up with the manuscript word by word, and marks words that look missing, added or changed.
- KeepDismiss3
Review
Listen to each flagged passage next to the script sentence, then keep it or dismiss it.
- x0:04:08p. 37x0:09:44p. 39proofed4
Export
Download a pickup sheet of the issues you kept, a pickup reel to listen through, and marker files for the edit.
Features
The tedious part, handled. The judgment calls, yours.
Secondpass does the word-by-word comparison and hands you a short list to listen to. Nothing reaches the pickup sheet unless you keep it.
Hear it, see it, decide.
Each flag opens on the waveform with the script sentence beside it and the suspect word highlighted. Play the sentence, keep or dismiss, and move to the next one, all from the keyboard.
- Timestamps to the word, plus the manuscript page
- Keyboard shortcuts for play, keep, dismiss and undo
- Notes on any flag, carried into the export
"See that they take plenty of ammunition, Von Horst," said Gridley, "for from what I have seen in this country we shall not have to carry any provisions."
…rifle see that they have plenty of ammunition von…
| File | Re-record | Start | End | Page | Mark | Notes |
|---|---|---|---|---|---|---|
| Chapter_1.mp3 | ||||||
| x | 0:19:56 | 0:20:28 | 10 | Misread | “In the main keel cabin were located the quarters for the officers and crew,…” | |
| Chapter_2.mp3 | ||||||
| x | 0:01:49 | 0:01:57 | 12 | Misread | “As the ship rose gracefully above the city, Zuppner, who was at the controls,…” | |
| x | 0:13:48 | 0:13:54 | 17 | Extra word | “The plan met with general approval and preparations were made for a stay of…” | |
| x | 0:23:06 | 0:23:12 | 20 | Extra word | “His tail was up and his head down as he broke into the trot…” | |
The deliverable, already filled in.
Everything you keep lands in a pickup sheet in the layout editors already use: file, re-record mark, start and end time, page, mark and script line. Clean chapters are marked proofed.
Download it as an Excel sheet or CSV, with a pickup reel of every kept line and marker files for your audio editing software.
Word-level comparison
Missing, added and changed words, each tied to its page and timestamp.
Audio checks
Head and tail silence, long pauses, levels, noise floor and format, against ACX or your own spec.
Fewer false alarms
Transcription mishears words. Secondpass re-listens to each flagged sentence with the script in hand and drops the ones it now hears correctly.
Pickup reels and markers
Every kept pickup in one audio file (and as separate clips), plus marker files so the editor lands right on each one.
Share with your narrator
Send a link to a chapter's flags. No account needed to listen.
Projects and chapters
Every book in one place, with progress for each chapter.
By the numbers
Measured on real audiobooks.
9.8 hours of narration across 3 books, each checked against a pickup list a person approved.
- narration errors on the approved pickup lists that Secondpass flagged
- 49 of 49
- flags to review per finished hour of audio
- ~12
- flags were real narration errors; you dismiss the rest
- 4 in 10
Our internal test set, November 2026. These books were also used to tune Secondpass, so read the numbers as indicative rather than a guarantee; we'll publish blind results as more books go through. A short flag list doesn't mean nothing else is wrong: see what Secondpass won't catch.
Made for your audiobook workflow
Built for the studio and the booth.
For Audiobook Studios
Proof every title for less.
Start each proof from a short list of flags instead of a full follow-along listen. Same checks and house spec on every book, reviewed as a team, one consistent sheet for your editors.
For Narrators
Catch mistakes before you deliver.
Check your chapters against the manuscript and the ACX spec, fix pickups while the mic is still set up, and send a clean sheet with your files.
For Proofreaders
Less searching. More reviewing.
Start from a short list of likely word errors instead of a blank sheet, and spend your ears on the calls that need them.
Running a studio? Book a demo with your own files.
Pricing
Pay for the audio, not the hours.
Secondpass is priced per finished hour (PFH): the running time of the audio you submit. Not the time it takes to process, and not the time you spend reviewing.
Proof
Start here$10/ finished hour
Narration checked against your manuscript, ready for you to review.
- Missing, added and changed words, with page and timestamp
- Audio checks against ACX or your own spec
- Review with the audio and script side by side
- Pickup sheet (Excel or CSV), pickup reel and marker files
Proof + Edit
Coming soon$30/ finished hour
Everything in Proof, with editing support on top.
- Everything in Proof
- Editing services: details coming soon
Studio
Custom
For publishers and studios with steady volume or a house spec.
- Volume pricing
- Your delivery spec saved as a preset
- Team accounts
A 6-hour audiobook on Proof at $10/PFH costs $60. That's the whole bill: no seats, no subscription.
FAQ
Questions, answered.
Something else on your mind? Ask us directly.
How does Secondpass work?
Upload the manuscript PDF and the chapter audio. Secondpass transcribes the narration with speech recognition, aligns it with the manuscript word by word, and flags places where they disagree. It then re-checks each flagged sentence to drop likely mishearings. You listen to what's left, keep or dismiss each flag, and export the ones you kept.
Does Secondpass replace a human proofreader?
No. It does the comparison legwork and gives you a short list of likely issues; a person still listens and decides. Every flag is a candidate, not a verdict.
What won't Secondpass catch?
Secondpass compares words, so it won't judge pronunciation, emphasis, character voices or pacing. It measures the room-tone level but doesn't yet flag individual clicks, mouth noise or background sounds. And a word the transcription mishears in exactly the way the narrator misread it can slip through. Plan on a human listen for performance and edit quality.
How does per-finished-hour pricing work?
You pay for the total running time of the audio you submit. A 6-hour book is billed as 6 hours, however long it takes to process or review.
What file formats are supported?
Manuscripts as PDF. Audio in the common formats (WAV, MP3, FLAC and others), one file per chapter. You can drop in a whole folder.
What kinds of errors can Secondpass find?
Missing, added and changed words, with the page and timestamp for each. It also checks the audio against a delivery spec (ACX or your own): head and tail silence, long pauses, levels, noise floor and format.
Can I export pickup sheets?
Yes. The issues you keep export as a pickup sheet (Excel or CSV) with file, times, page, mark and script line. You also get a pickup reel (every kept line in one audio file, plus individual clips) and marker files as CSV for your editing software.
How is my manuscript and audio handled?
Your files are stored privately and are visible only to people in your organization, plus anyone you send a share link to. Audio is transcribed by a third-party speech-recognition service. If you have specific requirements, get in touch before you upload.
Can studios book a demonstration?
Yes. Book a demo and we'll walk through a project, ideally with one of your own chapters.
Spend less time finding mistakes. More time finishing great audiobooks.
Let Secondpass do the comparison. You make the calls.