ACX Technical Requirements for AI-Narrated Audiobooks (and Where to Actually Distribute Them)

This guide covers ACX's technical audio specifications — the sample rate, loudness, noise floor, and file structure requirements you need to meet. These specs are also the standard for Apple Books, INaudio, and most other professional distribution platforms, so meeting them ensures your files are accepted everywhere.

Step 1: Choose your distribution platform

For AI-narrated audiobooks, your primary distribution options are: Spotify for Authors (free, non-exclusive, direct upload), Apple Books (via the Digital Narration programme or direct M4B upload), Google Play Books, Kobo Writing Life, and INaudio (formerly Findaway Voices; distributes to 30+ platforms including Spotify, Apple, Google, Kobo, and library networks).

ACX (ACX.com) is Audible's creator platform for human-narrated audiobooks. If you plan to submit a human-narrated title to ACX, create an account at ACX.com with your Amazon account and claim your title. ACX requires an existing Amazon listing (KDP ebook or print) for your book before you can submit an audiobook.

Step 2: Generate your audiobook with AI

Upload your manuscript (EPUB, PDF, DOCX, or TXT) to an AI audiobook generator. At TomeVox, the process is: upload file, select a voice, adjust speed if needed, click generate. Most books are ready within 24 hours.

Important: you need commercial distribution rights for the AI narration. Preview tiers on most platforms (including TomeVox's) are for personal use only. TomeVox's paid plans (from $49 early bird) include full commercial distribution rights.

Step 3: Verify your audio meets distribution technical specifications

These specs are the professional standard used by ACX, Apple Books, INaudio, and most other platforms. TomeVox's output meets all of them by default — this section is useful if you are manually verifying files or using another tool.

TomeVox handles all of the above automatically. The main thing to verify after downloading: that chapter files are split correctly and match your book's actual chapter structure.

Step 4: Upload to your distribution platform

For Spotify, Apple Books, and Google Play Books, upload your chapter MP3 files directly through each platform's author portal. For wider reach, INaudio (inaudio.com) handles distribution to 30+ platforms from a single upload — upload once, reach Spotify, Apple, Google, Kobo, and library networks simultaneously.

For platforms that require disclosure of AI narration (which is good practice on all of them): indicate AI narration during the upload workflow. Most platforms added a disclosure field in 2024–2025. Be accurate — this is both an ethical requirement and increasingly a contractual one.

Step 5: Decide on distribution strategy — wide vs. direct

For AI-narrated audiobooks, you have two main routes:

Recommendation for most indie authors: INaudio. One upload reaches 30+ platforms simultaneously and includes library distribution (OverDrive, Hoopla, Bibliotheca). The royalty split is slightly lower than direct upload on some platforms, but the reach advantage is significant — especially for authors who are not yet known on any single platform.

Step 6: Disclose AI narration

Every platform that accepts AI-narrated audiobooks requires disclosure during the upload process. This is an ethical and contractual requirement — not optional. Most platforms added a specific AI narration disclosure field in 2024–2025. Select it during upload.

Common submission issues and how to avoid them:

Expected timeline and costs

Total time from manuscript to live on Spotify, Apple Books, and INaudio:

Compare this to the traditional path: 6 to 12 weeks and $3,000 to $8,000. AI narration makes audiobook publishing accessible to every indie author, regardless of budget.