Understanding Audio Requirements
August 24, 2021

Your audiobook must meet specific audio requirements to be submitted to each of our partner platforms. Each platform has a different set of requirements. The specifications below are in place so you can get your audiobook onto as many platforms as possible.

Aim for the best audio quality possible with the tools you have at your disposal. Quality audio that meets submission requirements makes for a better listening experience for your audience (hopefully translating into more reviews, royalties, and recommendations for you!).

If you’re ready to roll up your sleeves and record your own audiobook, look over the audio specifications required for submission before you hit record. All of this technical jargon should start to make sense once you begin the recording process.

That’s great...but what does it all mean?!

Here’s a more in-depth look at the requirements and technical jargon.

Consistency in overall sound and formatting

Consistency in the sound and formatting of your audiobook creates a polished finished product. Tracks should maintain a consistent volume level (dB) and quality for a smooth listening experience. The listener shouldn’t be able to hear when you stopped recording one day and picked it up the next day.

To keep those volume levels as even as possible, sit the same distance away from the microphone, in the same environment, and use the same editing techniques throughout your audiobook. (Eliminate background noise, adjust peak levels with the limiter and amplify effect, edit out breaths, clicks, and mouth noise, etc.)

Decide on an introduction format for each chapter track, and stick to it for consistency. Keep a reference file for your project and refer back to it to ensure you have the same tone, pronunciation, character voices, and audio quality.

Mono or Stereo Files

All tracks must be either all mono or all stereo files— stick to one or the other. 

Mono files have all of the sound contained within one audio channel. This ensures each speaker provides the same output evenly. In the audacity export settings choose Force Export To Mono.

Stereo files are split into two audio channels. During recording, you’ll notice the sound waves populating in two places. No problem! If you’re recording in stereo, export each track as a stereo file (not joint stereo).

Include opening track and closing credits track

Any dedications or acknowledgements should be announced in a separate chapter track.

Opening Credits Track (Maximum 2 minutes): The opening credits track will (at minimum) include the title, author, and narrator, which must all match the information listed on the cover art and in the metadata exactly.

Example: Your opening credits track announces that the author's name is John Doe, but the cover art and metadata state the author's name is John Oliver Doe, you'll have to make an adjustment. This track must be no longer than 2 minutes.

Example Script
This is The Dog Crossed The Road
Written by John Doe 
Narrated by Jane Doe

Closing Credits Track (Maximum 2 minutes): Include the title, author, and narrator in the closing track. You may include additional credits as long as it stays under 2 minutes.

Example Script
You have been listening to The Dog Crossed The Road
Written by John Doe 
Narrated by Jane Doe
Editing and Mastering by Amelia Doe
Cover Art by Elle Doe
Thank you for listening/The End!

Human narration only— text-to-speech recordings are not allowed

If you are a computer or artificial intelligence, please do not submit your audiobook to us. Our partner platforms will not accept text-to-speech— humans only, please!

Each track must only contain one chapter or section

You'll upload your opening credits track, closing credits track, sample track, and each chapter track as an individual MP3. 

Each track must be no longer than 80 minutes

Let’s make it 79 minutes just to be safe! If your chapters are too long and you need to chop them up find a natural space to pause and add a chapter announcement (eg. Chapter 17 continued).

Each track must contain a section or chapter announcement at the beginning of the audio file

Tell your listener what they are about to hear and keep the format consistent. (eg. Foreword, Preface, Prologue, Chapter 1, Chapter 1 continued, Epilogue, Acknowledgements, etc.) 

Each track must contain 0.5 to 1 second of silence at the beginning of each track and 1 to 5 seconds of silence at the end of each track

Silence and room tone are two different things. Room tone is the ambient noise of the room you’re recording in. Silence is nothingness. At the beginning of every track, include 0.8 seconds of silence to be safe. At the end of every track, include 1 to 5 seconds of silence.
YouTube tutorials for front spacing and rear spacing.

Eliminate any extraneous sounds such as plosives, mic pops, mouse clicks, excessive mouth noise, and outtakes

If you are the narrator, do your best to avoid these excess sounds during the recording process rather than trying to adjust the files in the editing phase. 

Each track must measure between -23dB and -18dB RMS

RMS stands for Root Mean Square. Keeping your RMS between -23dB and -18dB ensures your audio isn’t too loud or too quiet.
YouTube tutorial to adjust RMS levels.

Each track must have a noise floor no higher than -60dB RMS

Noise Floor is a measurement of how loud your room tone is (the white noise of your recording space). If you stood perfectly still in your recording space and hit record, how much noise is being picked up by the microphone? If you’re recording and you hear the rumbling of a garbage truck, wait until it has made its rounds and start again. Trains, planes, and automobiles in the background can be distracting and hard to remove.
YouTube tutorial to adjust RMS levels.

Each track must have peak values no higher than -3dB

If your track is peaking above -3dB (decibel), the audio can sound distorted, like the signal is breaking up.

When the audio peaks past the maximum allowable limit, it clips off the top of the sound wave, decreasing the audio quality. To avoid peaking, run a noise reduction with a maximum peak value of -6dB.

Watch the levels rise and drop as you speak into the microphone. It can be a lot to pay attention to all at once but it's best to catch it while recording rather than fixing it in the editing phase.
YouTube tutorial to adjust peak levels.

Each track must be 192 kbps (Export Setting)

This is the data transfer rate or bit rate currently accepted by all of our partners.

It refers to the average amount of data per second, as the kbps (kilobits per second) increases it gets closer to the original quality, but the file size also increases at the same time. 192 kbps ensures a small file size without decreasing audio quality.

Each track must be in MP3 file format (Export Setting)

Export each file as an mp3.

Constant Bit Rate (CBR) (Export Setting)

To avoid any quality drops throughout your track, choose ‘constant bit rate’ (CBR) when exporting your track. This keeps the bit rate consistent (192 kbps) throughout the track instead of fluctuating it up and down. 

44.1 kHz (Recording Setting)

This is the sample rate (the number of samples per second taken from a continuous signal) that you record at. Depending on the audio software you’re using, this will be a setting you can choose before you record. If you’re using audacity you’ll see this selection in the bottom left corner (also denoted as 44,100 Hz). This sample rate helps keep the file size small without decreasing audio quality.

Each file should be no larger than 170MB

If your track follows all audio requirements, your file will be no larger than 170MB.

Export Settings

 

Hop on over to the Author's Republic YouTube Channel to check out more tutorials.

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