• Home
  • AA, AAX, AAXC, AAX+, ADH: All Audible Formats Explained
audible format

AA, AAX, AAXC, AAX+, ADH: All Audible Formats Explained

February 6, 2021 terminator 0 Comments

What formats are audible audiobooks? AA, AAX, AAX, AAXC, adh, and AAX+ –these are all audible formats. You may be surprised to see that there are so many different types of audible file formats. Why do so many audible formats exist and is there a best audible format? In this article, I will explain the aa, aax, aaxc, adh and aax+ so that you’ll pick up a format that best suits your needs.

Please note: all audible file formats are audible’s proprietary formats.

Old Audible Format: AA

Audible .aa format is the older audible format which is also the standard format that are encoded standard Audible file format to contain an audiobook with chapters. It supports splitting the book into parts.

AA can be divided into three subsidiary formats – Format 4, Format 3, and Format 2, based on the audio quality. From a quality perspective, Format 2 and Format 3 have been compared as listening to AM radio and FM radio, respectively. Format 4 is a more modern format akin to most MP3 files. All aa format audio books are mono.

Audible AA format Bit rate Comparable to 
Format 2 8 Kbps AM radio quality 
Format 3 16 Kbps FM radio quality 
Format 4 32 Kbps Standard MP3 audio quality 

Enhanced Audible Format: AAX

.AAX format is the audible enhanced format compared to audible .aax format, which is the minimally compressed audible format. The bitrate on this format is 64Kbit/s. That means AAX format is high in quality but large in size, and takes longer time to download. Audible AAX is now offers stereo recordings.

Please note: almost all audible books are applied to the .aax format. That means if you download audible books on Windows and Mac, you’ll only get audible .AAX files. It is the most widely used audible format.


Audible audio formats Format 4 Enhanced 
File formats .aa .aax 
Sound quality MP3 CD 
File size for 1 hour of audio 14.4 MB 28.8 MB 
Bit rate 32 Kbps 64 Kbps 
Sample rate 22.050 kHz 22.050 kHz 

Audible New Format: AAXC (Android Audible Format)

AAXC format is new format that developed by Audible to address much tougher copyright protection to their audible books. It doesn’t show any quality changes compared to Audible .aax format. Until now, it is only applied to audible android app. That mean if you want to get AAXC files, you need to download audible books via audible android app.

How to Convert AAXC to MP3 format?

Audible Download Link Format: ADH

What is .adh file format? The admhelper.adh file (Audible Download Helper) is not a real audible format, but a protocol that help that Audible Download Manger to download your purchased audible books form audible.com library. Usually, .adh file will show when you try to download audible books from website directly on Windows. If you are on Mac, you’ll get the .aax format straightforward.

To download the real audible books, just open .adh file with Audible Download Manger and eventually you’ll get the audible aa, or aax format.

How to download audible adh to aax?


The internet talks about an AAX+ format but I cannot find any of my downloads in this format. So, I don’t have many knowledges to share on this format.

What devices or apps are compatible with Audible format?

Although there are so many audible formats, but the most common audible file format in use today is AAX. It is well known that audible aax format is audible proprietary format . Therefore, its limitations come in the form of compatibility, as a lot of software are unable to recognize the AAX(audible enhanced format), making it ideal for only a select type of user. Let me list the audible compatible devices and apps.

Audible compatible Kindle devices

  • Kindle Paperwhite (10th Gen)
  • Kindle Oasis (8th Gen)
  • Kindle (8th Gen)
  • Kindle (1st & 2nd Gen)
  • Kindle Touch
  • Kindle Keyboard
  • Kindle DX
  • Kindle Fire (1st & 2nd Gen)
  • Kindle Fire HD (2nd & 3rd Gen)
  • Kindle Fire HDX (3rd Gen)
  • Fire HDX (4th Gen)
  • Fire HD (4th-8th Gen)
  • Fire (5th Gen)

Audible compatible mp3 players

  • Sandisk MP3 Players
  • Creative MP3 Players
  • Garmin & Tom Tom GPS Devices

Audible Compatible Apps (Audible Player Windows/Mac)

  • Audible Windows 10 App
  • Audible Manager
  • Windows Media Player
  • ITunes/Apple Books
  • Audible Cloud Player

How to Make Audible Format Compatible with any Players?

An mp3 is the most popular type of lossy audio. The main advantage of MP3 is the compact file size, compatibility with digital media players, and good sound quality. Therefore, to make audible format compatible with any player, we should convert audible aax to mp3 format.

To make this happen, you’ll need iSummersoft Audible Converter.

Download Audible books and then add them to iSummersoft Audible Coverter. Then click “Convert to MP3” to rip audible books to mp3 format easily.

For more knowledges about audible formats, please share in the comments sections.

leave a comment