What Is ACX? A Plain-English Guide for Independently Published Authors
Everything you need to know about the Audiobook Creation Exchange — before you start your project
If you've started researching audiobook production you've probably encountered the term ACX — and if you're like most independently published authors, it wasn't immediately clear what it meant or why it mattered.
ACX stands for Audiobook Creation Exchange. It's Amazon's platform for producing and distributing audiobooks to Audible, Amazon, and iTunes — and for most independently published authors it's the primary pathway to getting your audiobook in front of listeners.
If you haven't yet decided whether to narrate your own audiobook or hire a professional narrator, our guide to author narration vs professional narration covers that decision in full.
This guide explains exactly what ACX is, how it works, what it requires, and what you need to know before you start your audiobook project.
We're the team at .wav Enthusiast, a Downtown Los Angeles audiobook production studio. We handle ACX submissions on behalf of every author we work with — and we've never had a file rejected at submission. This is the guide we walk every new client through before we begin.
What is ACX?
ACX — the Audiobook Creation Exchange — is a marketplace and distribution platform owned and operated by Amazon. It was launched in 2011 and has become the dominant pathway for independently published authors to produce and distribute audiobooks.
ACX does three things:
It connects rights holders with producers and narrators
Authors who own their audiobook rights can list their titles on ACX and connect with narrators, engineers, and production studios. Think of it as a marketplace where the supply side (production talent) meets the demand side (authors with books to produce).
It provides a technical framework for production
ACX publishes detailed technical specifications that all audiobooks must meet before they can be distributed through Audible. These specs cover file format, loudness, peak ceiling, noise floor, and file structure.
It handles distribution
Once your audiobook is produced and approved, ACX distributes it to Audible, Amazon, and iTunes — the three largest audiobook platforms in the world. Audible alone has over 40 million listeners.
Who can use ACX?
ACX is available to anyone who holds the audiobook rights to a published or soon-to-be-published book. This includes:
Independently published authors
If you self-published through KDP, IngramSpark, Draft2Digital, or any other independent platform you almost certainly own your audiobook rights and can use ACX immediately.
Traditional publishing authors with retained rights
If you published through a traditional publisher but retained your audiobook rights — check your contract carefully — you can use ACX to produce and distribute your audiobook independently.
Publishers and production companies
ACX is also used by publishers and production houses to manage audiobook projects at scale. At .wav Enthusiast we have worked with both major publishers and independent authors through the ACX platform.
If you're not sure whether you own your audiobook rights, check your publishing contract or consult a publishing attorney before proceeding.
How does ACX work?
The ACX process has four main stages:
Stage 1 — Claim your title
Create a free ACX account at acx.com using your Amazon login. Search for your book by title or ISBN and click "This is my book" to claim your audiobook rights on the platform.
Stage 2 — Choose your production path
You have two options on ACX:
Pay for production upfront - you hire a studio or narrator at an agreed rate and retain 100% of your royalties minus ACX's distribution fee.
Royalty share - a narrator or producer works for free in exchange for a percentage of future royalties. More on this below.
Stage 3 — Produce your audiobook
Your audiobook is recorded, edited, mixed, and mastered to ACX technical specifications. This is where a professional studio like .wav Enthusiast handles the process on your behalf.
Stage 4 — Submit and distribute
Once production is complete you upload your files through your ACX dashboard. ACX reviews them for technical compliance — typically 7 to 14 business days — and if approved your audiobook goes live on Audible, Amazon, and iTunes within approximately 10 business days.
ACX distribution options — exclusive vs non-exclusive
When you submit your audiobook through ACX you choose between two distribution options. This is one of the most important decisions you'll make and it directly affects your royalty rate.
Exclusive distribution
Your audiobook is available only on Audible, Amazon, and iTunes. You cannot distribute through Spotify, Voices, Libro.fm, or any other platform.
Royalty rate: 50% of list price
Contract term: 7 years
Non-exclusive distribution
Your audiobook is available on Audible, Amazon, and iTunes AND you can simultaneously distribute through other platforms including Spotify, Voices, Authors Republic, and Libro.fm.
Royalty rate: 30% of list price
Contract term: No lock-in
Which should you choose?
Exclusive distribution makes sense if Audible is your primary market and you want to maximize your per-sale royalty rate. The 50% rate is significantly higher than the 30% non-exclusive rate.
Non-exclusive distribution makes sense if you want to maximize reach across platforms or if you're building a long-term catalog and don't want to be locked into Audible exclusivity for 7 years.
At .wav Enthusiast we handle distribution to whatever platforms you choose — not just Audible. We'll walk you through the decision during your free consultation.
ACX royalty share — what you need to know
ACX's royalty share program allows authors to have their audiobook produced for free — with the producer or narrator receiving a percentage of future royalties instead of an upfront fee.
On the surface this sounds appealing, especially for authors on a tight budget. But there are significant trade-offs worth understanding before you choose this path.
You give up 20% to 40% of royalties
Under a royalty share agreement the producer receives between 20% and 40% of your audiobook royalties — for the life of the title, which under ACX's exclusive agreement means 7 years. For a book that sells well this can add up to far more than the cost of upfront production.
Quality is inconsistent
Producers willing to work on royalty share are often newer to the industry or working across high volumes of projects simultaneously. Your book may receive less attention and less experienced direction than a paid production. The result is audible.
You lose creative control
Royalty share producers have a financial stake in your project — which can create misaligned incentives around production decisions, timelines, and quality standards.
The honest assessment:
For most independently published authors who are serious about their audiobook as a long-term revenue-generating asset, upfront professional production is the better investment. The royalties you retain over 7 years almost always exceed the upfront production cost.
For a complete breakdown of audiobook production costs and how to estimate your project budget see our guide to how much audiobook production costs.
ACX technical requirements — what your audio must meet
This is where most self-produced audiobooks run into trouble. ACX has strict technical specifications and files that don't meet them are rejected — sometimes after weeks of waiting in the review queue.
Here are the key requirements:
File format
MP3 at constant bit rate (CBR) 192 kbps or higher, 44.1 kHz, stereo or mono.
Integrated loudness
Between -18 and -23 LUFS. This measures the average loudness of your audio over time.
Peak ceiling
No higher than -3 dB. This is the maximum loudness of any single moment in your audio.
Noise floor
At least 60 dB signal-to-noise ratio. This measures how quiet your recording environment is relative to your voice. Street noise, HVAC systems, and ambient room sound are the most common reasons files fail this requirement.
File structure
Each chapter as a separate file, plus opening credits and closing credits files.
Room tone
0.5 to 1 second of room tone — the sound of silence in your recording environment — at the beginning and end of each file.
Why this matters for home recording
The noise floor requirement is the most commonly failed spec for home recordings. A genuinely quiet recording environment is harder to achieve than most authors expect — and the penalty for failing is resubmission delays of several weeks.
At .wav Enthusiast every file we deliver is mastered to ACX specifications and reviewed against all requirements before submission. We've never had a file rejected at submission.
What ACX doesn't cover
ACX is a powerful platform but it's not a full-service solution. Here's what it doesn't do that you'll need to handle separately or through your production studio:
Cover art
ACX requires a square image between 2400x2400 and 3000x3000 pixels. Your existing book cover may need to be reformatted to a square aspect ratio before submission. At .wav Enthusiast we handle cover art reformatting as part of our full-service package.
Metadata
Title, author name, narrator name, publisher, and a description of up to 2,000 characters all need to be entered at submission. We handle metadata entry on behalf of every client.
ISBNs
Your audiobook needs its own ISBN separate from your print and ebook editions. We handle ISBN assignment as part of our service.
Wide distribution
If you choose non-exclusive distribution through ACX you'll need to separately distribute to Spotify, Voices, Libro.fm, and other platforms. At .wav Enthusiast we handle distribution to all platforms you choose.
Marketing and promotion
ACX distributes your audiobook but doesn't market it. Building Audible reviews, promoting through your author platform, and running ads are all separate activities that determine how well your audiobook sells after it's live.
For a complete step-by-step walkthrough of the full process from manuscript to live on Audible see our guide to how to get your book on Audible.
Common ACX questions answered
How long does ACX review take?
ACX typically reviews submitted files within 7 to 14 business days. Once approved your audiobook goes live within approximately 10 additional business days.
Can I change my distribution preference after submitting?
You can switch from exclusive to non-exclusive distribution but there are conditions and waiting periods. It's worth making the right decision upfront rather than trying to change it later.
What happens if my files are rejected?
ACX notifies you by email with the specific reason for rejection. You correct the issue and resubmit — which restarts the review clock. This is why working with a professional studio that reviews files before submission matters.
Do I need an ACX account before working with a studio?
Not necessarily. At .wav Enthusiast we can handle your ACX account setup and submission as part of our full-service package. You don't need to navigate the platform yourself.
Is ACX the only way to get on Audible?
For independently published authors yes — ACX is the primary direct pathway to Audible. Some aggregators like Findaway Voices (now Spotify for Authors) also distribute to Audible in certain markets but ACX remains the most direct and widely used route.
Ready to start your audiobook project?
If you're an independently published author ready to produce your audiobook, we handle everything — including ACX account setup, technical compliance, submission, and distribution to every platform you choose.
Start with a free consultation - no commitment, no pressure. We'll learn about your book, walk you through the process, and give you a custom quote.
Visit our Independent Authors page to learn more, or contact us directly:
📍 1667 N Main St, Unit B206
Downtown Los Angeles, CA 90012
📞 (909) 702-2280
✉️ info@waventhusiast.com
Written by the .wav Enthusiast team | Downtown Los Angeles Audiobook Production Studio
