Audio Requirements for Submitting your Completed Audiobook

Please review our technical requirements for uploading audiobooks. If you have questions regarding these requirements, please contact audio@acx.com. We are here to assist you.

If you fail to follow these specifications, your audiobook will be rejected. Please note, our policy is to only allow one resubmission of your rejected audiobook. If your resubmitted audiobook still does not adhere to our specifications, then our policy is to terminate the agreement.

Your audiobook must:

  • Must exhibit an overall sound quality on par with other offerings on Audible.com. (Please see below for example audio.)
  • Include Opening and Closing Credits. If you have not already recorded these, please see our recommended format here.
  • Be separated into individual chapters. Each chapter can have a maximum length of 120 minutes and cannot be larger than 170MB. If a chapter exceeds that maximum length or size, it must be divided into two files at a suitable point in the narration. If the majority of the chapters are each less than five minutes long and the audiobook contains over 50 chapters, you may combine up to 5 chapters per file, making sure each grouping contains the same number of files. Chapters over 5 minutes long may not be combined. Do not include the opening and closing credits within the first and last chapter, they must each be independent files.
  • There must be 0.5 seconds at the start of each file, and 3.5 seconds at the end.
  • You must include a Retail Audio Sample. More information on what is required is listed at the bottom of this page
  • All files must be 192 kbps MP3 with a maximum file size of 170MB. For help converting your files to our MP3 spec, please see this tutorial. Mono or stereo files are accepted but all files must be identical in this respect.
  • All files must be 44.1kHz.
  • All files should measure between -23dB and -18dB RMS, with peaks hovering around -3dB. Your noise floor should fall between -60dB and -50dB.
  • Audiobooks produced using text-to-speech software are not allowed.

Delivering Your Audiobook

  • All files must be uploaded via the ACX site. We do not accept submissions of any other kind.
  • Each file must be uploaded individually in the order it is to be heard by the listener.

Credits

The opening and closing credits must be uploaded to the designated locations at the beginning and end of the audiobook. If you have not already recorded them, we suggest the following template:

Opening Credits:
“[title of audiobook]
Written by [name of author]
Narrated by [name of narrator]

Closing Credits:
This has been [title of audiobook]
Written by [name of author]
Narrated by [name of narrator]
Copyright [year and name of copyright holder]
Production copyright [year it was recorded] by [company name]

Sample Selection

Please select and include a “sample” snippet of audio from your final audiobook. It will be used on Audible.com and iTunes to let potential customers sample the audiobook. This should be a separate audio file, chosen using the following guidelines:

  1. The sample should be anywhere from 1 to 5 minutes long.
  2. Please select a compelling sample that you feel will do a good job of selling the book.
  3. You may decide to cut the sample directly from the start of the book, as this is often the best set-up and pulls you in to the rest of the book, but please do not include announcements, such as “introduction” or “chapter 1.”
  4. The sample should start with narration (i.e. not the title credits).
  5. If the book is erotic, please do your best to choose a “clean”, but romantic sample.