Self-Publishing an Audiobook on ACX: What You Need to Know

ACX, which stands for Audiobook Creation Exchange, is the primary gateway to selling your audiobook on Audible, Amazon, and Apple Books. For indie authors, it is the single most important audiobook distribution platform. But navigating ACX for the first time can be confusing. This guide covers everything you need to know, from setting up your account to uploading your finished files.

What Is ACX?

ACX is Amazon's platform for audiobook production and distribution. It serves two purposes: it is a marketplace where authors can find narrators, and it is a distribution pipeline that gets your audiobook onto Audible, Amazon, and Apple Books. You can use ACX even if you already have a finished audiobook and do not need their narrator marketplace.

If you created your audiobook using an AI narration tool like AudioAIBook, you already have your finished audio files. You will use ACX purely as a distribution platform.

Setting Up Your ACX Account

To create an ACX account, you need:

• An Amazon account (create one if you do not have one)
• Your book's ISBN (if you have one) or ASIN (Amazon's identifier, which your ebook or paperback already has)
• Tax information for royalty payments
• A bank account for direct deposit

Go to acx.com and sign in with your Amazon credentials. You will be prompted to complete your profile and tax information. This is a one-time setup.

Claiming Your Title

Before uploading audio, you need to "claim" your book on ACX. Search for your book by title, author name, or ISBN/ASIN. ACX will find your existing ebook or paperback listing on Amazon and link it to your audiobook project. If your book is not yet on Amazon, you will need to publish it there first (even if just as a Kindle ebook) to create the listing that ACX will attach the audio to.

Audio File Requirements

ACX has specific technical requirements for audio files. Your files must meet these specifications or they will be rejected:

• Format: MP3 (192 kbps or higher) or M4A
• Bit rate: Constant bit rate (CBR), 192 kbps or higher
• Sample rate: 44.1 kHz
• Channels: Mono
• Each file: One chapter per file, with chapter files named in order
• Opening credits: A separate audio file with the book title, author name, and narrator credit
• Closing credits: A separate audio file with end credits
• Room tone: 0.5 to 1 second of silence at the beginning and end of each file
• Noise floor: Must be below -60 dB
• Peak volume: Must not exceed -3 dB
• RMS level: Between -23 dB and -18 dB

If you are using AI-generated audio from a platform like AudioAIBook, the technical specifications are generally already met. The MP3 files produced by AI tools typically conform to ACX requirements. However, you will likely need to create separate opening and closing credit files. You can generate these using the same AI voice that narrated your book.

Exclusive vs Non-Exclusive Distribution

When setting up your title on ACX, you will choose between two distribution options:

Exclusive Distribution (40% Royalty)

• Your audiobook is available only on Audible, Amazon, and Apple Books
• You earn 40% of the sale price
• 7-year exclusivity commitment
• Audible may include your book in promotional programs that drive sales

Non-Exclusive Distribution (25% Royalty)

• Your audiobook is on Audible, Amazon, and Apple Books
• You can also distribute through other platforms (Findaway, Google Play, etc.)
• You earn 25% of the sale price through ACX
• No exclusivity requirement

The 15% royalty difference is significant. On a $15 audiobook, exclusive earns you $6 per sale versus $3.75 for non-exclusive. For most indie authors, starting with exclusive makes sense unless you have a specific strategy for wide distribution.

The Review Process

After uploading your files, ACX reviews them for technical quality and content compliance. This review typically takes 2 to 4 weeks. During review, ACX checks:

• Audio meets technical specifications
• Content matches the book description
• No rights issues or duplicate content
• Opening and closing credits are present and accurate

If your submission is rejected, ACX provides specific feedback on what needs to be fixed. Common rejection reasons include incorrect audio levels, missing credit files, and noise issues.

Pricing Your Audiobook

On ACX, you do not set a retail price directly. Audible determines the retail price based on the audiobook's length. However, most audiobooks are purchased with Audible credits (one credit per audiobook regardless of price) rather than at retail price. This means your pricing strategy matters less on Audible than on other platforms.

Common Pitfalls to Avoid

• Forgetting opening and closing credits. ACX requires these as separate files. Do not skip them.
• Incorrect file naming. Name your files in sequential order (001_opening_credits.mp3, 002_chapter_01.mp3, etc.) to ensure correct chapter order.
• Mismatched metadata. Your audiobook title, author name, and description must match your ebook/paperback listing exactly.
• Choosing royalty share by mistake. If you already have finished audio from AI narration, you do not need to share royalties with a narrator. Make sure you select the "I will pay for production myself" option.
• Not verifying the cover image. ACX requires a square cover image (2400x2400 pixels minimum). Your ebook cover dimensions will not work.

Publishing on ACX is straightforward once you understand the requirements. With AI-generated audio files from a tool like AudioAIBook, you already have the hardest part done. Prepare your credit files, format your cover, upload everything, and you will be live on Audible within a few weeks.