There are a few ways that books end up on (as well as iTunes and Amazon, which also draw from the same library of books). The first, and most common way, is that the book’s publisher has the audiobook rights, produces a recording, and submits the book to Amazon to go up on Audible. For authors who retain their audiobook rights, or those who are self- or independently-published, the process can be a little more complex.

Enter Audible‘s Audiobook Creation Exchange (ACX). This program, launched in 2011, helps authors and publishers create and submit audio versions of their books. After a successful launch, the program grew exponentially, producing 10 times as ┬ámany books in its second year as it did in its first. In fact, Audible reports that ACX provided them with three times more titles last year than any other source of audiobooks. Using the platform, authors can record their own versions or call for voice auditions from professional voice actors who will record a version for them. Users routinely report that ACX books are just as high quality as other professional audio productions.

And ACX isn’t just good news for authors, publishers, and voice actors, it’s good news for audiobook listeners as well. With such a low barrier to entry to the audiobook market, more indie books are making it onto the site, meaning that your Audible membership gives you access to more titles than it ever has before.