Create top-quality audiobooks, and maximize your sales potential by providing the best overall listening experience.
Audiobooks uploaded to ACX must adhere to the following requirements. The ACX Quality Assurance team may reject titles that do not meet these standards, and their retail release may be delayed. The following requirements help ensure customers get a great listen.
Your submitted audiobook must:
Each uploaded audio file must:
- be consistent in overall sound and formatting and be comprised of all mono or all stereo files
- include opening and closing credits and a retail audio sample that is between one and five minutes long
- contain only one chapter/section that's shorter than 120 minutes and the section header must be read aloud
- have room tone at the head and at the tail and be free of extraneous sounds
- measure between -23dB and -18dB RMS and have -3dB peak values and a maximum -60dB noise floor
- be a 192kbps or higher MP3, Constant Bit Rate (CBR) at 44.1 kHz
Why? Consistency in audio levels, tone, noise level, spacing, and pronunciation helps give the listener a great experience. Drastic changes can be jarring and are not in keeping with a professional production. Extreme fluctuations in volume means the listener will have to keep a hand on the volume control of their listening device. This detracts from the listening experience and may lead to poor reviews and reduced sales.
Submitted audiobooks may not contain both mono and stereo files. Stereo files must not be joint-stereo. Mono files are strongly recommended.
Why? Before being added to the Audible store, submitted audiobooks are encoded in a variety of formats that listeners have the option of downloading. Titles submitted with both stereo and mono files will cause errors during this encoding process and the title’s retail release may be delayed. We recommend mono for all of your files as this may prove to be the smoothest path that also allows for audio consistency.
At minimum, the opening credits must note the name of the audiobook, the name of the author(s), and the name of the narrator(s). Closing credits must, at minimum, state “the end”.
Why? Opening credits help listeners confirm what they are about to hear, and that they are listening to the start of the audiobook! Closing credits confirm to the listener they have reached the end.
Recommended Opening Credits:
“[title of audiobook]" *
Written by [name of author] *
Narrated by [name of narrator] *
Recommended 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]
This sample should start with narration, not opening credits or music. If the audiobook is erotic, the sample should not include explicit material.
Why? The retail audio sample used on Audible and Amazon is a preview of your audiobook. A great sample will show off your material and attract paying customers! (Note: iTunes automatically uses the first five minutes of the book as their sample.)
Why? Listeners purchasing audiobooks from Audible and partner channels expect them to be narrated by people!
You’ll be prompted to upload each file individually. Both the opening credits and closing credits must be separate files.
Why? This ensures listeners can easily navigate between sections, and that skipping forwards or backwards moves them forward or back one section. Combining multiple sections in one file creates a confusing navigation experience. If the audiobook is not in a traditional chapterized format and you’re unsure how best to separate your files, please contact us directly for guidance.
If a section will be over 120 minutes long, find a good break in the narration, and split the section into two files. If the section began with a header, such as “Chapter 2”, we recommend starting the second file with “Chapter 2 continued”. This will help ensure listeners can easily navigate from section to section.
Why? By including these announcements, you’re helping the listener understand what section of the book they are listening to without having to look at their player. Be consistent - a listener may think content is missing if most headers are read, but some are not.
Why? Leaving this space gives listeners an audio cue that they have reached the beginning or end of a section. This space is also required to ensure titles are successfully encoded in the many formats made available to customers.
Why? Extraneous sounds can be distracting to listeners, and outtakes sound unprofessional. Each can elicit bad reviews and bad reviews can hurt sales!
Why? Put simply, this means the files fall within a specific volume range. By keeping all files within this range, listener experience is enhanced – not too loud, and not too soft. In being consistent, listeners won’t have to constantly adjust the volume of their playback device.
Why? By leaving this headroom you’ll reduce the possibility of distortion, which can seriously reduce the quality of the listening experience. This headroom is also needed to ensure files are successfully encoded.
Why? Noisy files make it difficult for listeners to focus on the material.
Why? Before going on sale in the Audible store, titles are encoded in a variety of formats that customers have the option of downloading. 192kbps (or higher), Constant Bit Rate MP3 files are required so this encoding process works without error. You may upload 256kbps or 320kbps files if you’d like, but the difference in quality heard by listeners will be negligible. Please see our tutorial for creating MP3s to our spec, if this work is unfamiliar to you.
Why? Before going on sale in the Audible store, titles are encoded in a variety of formats that listeners have the option of downloading. 44.1 kHz files are required so this process works without error.
If a file will be over 170MB, find a good break in the narration and split the section into two files. If the section/part began with a header, such as “Chapter 2”, we recommend starting the second file with “Chapter 2 continued”. This will help ensure listeners can easily navigate from section to section.