Getting a book published the right way means clearing two separate sets of technical requirements: ACX’s automated audio checks if you’re producing an audiobook, and KDP/IngramSpark’s print and eBook formatting rules if you’re publishing in text. Most self-published authors run into both. This guide covers what each actually requires, in plain terms, with a deeper walkthrough linked for every section.
Part 1: Getting your audiobook ACX-approved
ACX runs an automated technical check on every file before a human ever listens to it. The check is strict, non-negotiable, and easy to fail even when the narration itself sounds great. Five issues account for almost every rejection: background noise, incorrect RMS/peak levels, missing room tone, wrong file structure, and missing credits.
Read the full breakdown of all 5 rejection reasons and how to avoid each one →
Room tone: the detail almost everyone gets wrong
One specific requirement trips up more submissions than any other: ACX expects roughly 0.5–1 second of real, recorded room tone at the head and tail of every file — not digital silence. It’s a small detail with an outsized effect on whether a file passes first try.
Read exactly how long room tone should be, and why →
Choosing the right narrator
Before any of the technical mastering happens, the narrator is the single biggest factor in how an audiobook is actually received by listeners. The right voice for a thriller is rarely the right voice for a cozy romance.
Read the practical framework for choosing a narrator →
Where to distribute once it’s approved
ACX (exclusive route to Audible), Voices by INaudio (formerly Findaway Voices, wide distribution), and Spotify for Authors (direct, non-exclusive) each offer different royalty structures and reach. The right choice depends on whether Audible’s audience is where your readers already are.
Compare ACX, Voices by INaudio and Spotify for Authors →
Part 2: Formatting for print and digital
Book formatting is a separate discipline from audiobook production, with its own strict, platform-specific rules. Amazon KDP, IngramSpark and eBook retailers each expect files prepared to their exact specifications — get it wrong and the rejection (or worse, a published book with broken formatting) happens after the fact.
Preparing your manuscript before formatting begins
A formatter rebuilds a book’s typography from scratch in professional layout software — which means most of what makes a manuscript “submission-ready” for a literary agent doesn’t actually matter for formatting. What does matter: final edited text, images supplied as separate original files, and clear notes on where the book will publish.
Read exactly what to send a formatter, and what not to worry about →
Print formatting vs. eBook formatting
Print is a fixed layout: every page break, margin and widow/orphan is locked in place. EBook formatting is reflowable: the same file needs to look correct whether it’s read on a phone, a Kindle, or a tablet, at any font size the reader chooses. They are genuinely different jobs, not the same file exported twice.
Read the full difference between print and eBook formatting →
KDP margins and trim size
Amazon KDP’s print-on-demand system has strict, page-count-dependent margin requirements, plus separate rules for bleed and gutter. Most print-file rejections trace back to one of these specifics being missed.
Read how trim size, margins, bleed and gutter actually work together →
Where to go from here
If you’re early in the process, start with whichever half of this guide matches what you’re working on right now — audiobook production or print/eBook formatting — and use the linked articles above as your working checklist. If you’d rather have a second pair of professional eyes on the actual file before you submit it anywhere, that’s exactly what both services on this site are built for.
