ACX Now Open To UK Authors – My Experience

Montgomery on Audible

Montgomery on Audible

The Audiobook Creation Exchange, which enables independent authors to submit audiobooks to Audible and iTunes, has been the privilege of US residents only since its inception in 2011. Now, however, it has opened up its doors to us in the UK…. so I thought I’d give it a shot.

Why not?

And, to my surprise, it was a clear, straightforward process. One reason for this is that I already had the audio recorded and processed, using Audacity ( and a Shure PG42 (oh, yes!), so the first thing to do was to create mp3 files that met the ACX criteria. Audio files must:

  • Be free of extraneous sounds such as plosives, mic pops, mouse clicks, excessive mouth noise, and outtakes. A decent condensing mic with a pop shield is the way to tackle the plosives etc. The outtakes, however, will take time and effort as you trawl through your audio, correcting your mistakes. If you’re anything like me, there’ll be outtakes in almost every sentence…. but then I’m useless at read and have a tendency to mumble and slur my words.
  • Be split into chapters, plus an intro, an outro and up to five minutes of ‘preview’ audio. I record each of these in a separate file which keeps things nice and easy. The intro and outro are the usual things: name of book / author, ‘You have been listening to…’ – that sort of thing. The five minute preview can be taken from anywhere in the book, which means you can find something attention grabbing or with a cliff-hanger ending.
  • Have between 0.5 and 1 second of room tone at the head, and between 1 and 5 seconds of room tone at the tail. All this means is that each of these individual files need an amount of silence at the start (just under 1 second) and at the end (around 3 seconds).
  • Have a noise floor no higher than -60dB RMS. This is easy enough with a decent condensing microphone. But it’s always worth recording a few seconds of silence each time you record so you can use it as a sample for noise removal (such as that provided by Audacity)
  • Measure between -23dB and -18dB RMS. This isn’t something to worry about, as the following items take care of RMS. However, there is free software out there that analyses the RMS of audio files, such as Audioleak (
  • Be consistent in overall sound and formatting. There’s a fantastic piece of software called the Levelator (for Windows or Mac). Once you have an audio file, simply export it as a wav file (lossless) and run it through the Levelator, then import it back into Audacity or whatever software you’re using. As if my magic (maybe even by actual magic) the file is all consistent in overall sound. All those bits where the audio quietens at the end of sentences, and the suddenly overloud bits where someone in the book is shouting, are now consistent in level. Brilliant!
  • Have peak values no higher than -3dB. Having levelled the audio, simply normalise the whole thing to -3dB and you’re done. As I said, these two steps (Levelator and Normalise) will ensure the RMS is taken care of.
  • Be 192kbps or higher mono MP3, Constant Bit Rate (CBR) at 44.1 kHz. More technical sounding stuff, but really it’s quite simple. All you need to do is export each completed audio file as an MP3, making sure the settings are as follows: sample rate-44100, channels-mono, bit rate-constant. As for the quality, I go with 320kbps, because it’s near perfect audio reproduction. If you’re using FFMPEG, the settings on my Mac are: ffmpeg -i “input audio.wav” -ac 1 -ab 320k -ar 44100 -acodec libmp3lame “output audio.mp3”.

In all honesty, I hadn’t expected this to be quite so technical and dull… still if you’ve got this far, you must have a decent threshold for such things.

So, having got my mp3 files ready, all I did on the ACX site was sign up using my Amazon login details, since they own ACX, click on “+ADD YOUR TITLE” in the top right, find the book I’d recorded (Montgomery’s Trouble in the Underworld) and select ‘This is my book’. I was then presented with three choices:

  1. I’m looking for someone to narrate and produce my audiobook
  2. I have this book in audio and want to sell it
  3. I will narrate my own book and upload the audio later

The first option take you through a process of finding and auditioning people to narrate your audiobook. As I narrate my own, I did not go through this process, but you can select the type of voice you are after and upload a script for auditions.

The third option simply adds the book, on hold, to your list of projects

I went straight for number two, which, after a few pages of filling in details about the book (most of which was already there thanks to Amazon), opened an area for uploading my files. It was very straightforward and user-friendly and I added the files in no time (or at least, only as long as it takes to upload an entire audiobook, so actually quite a while!). Once done, I submitted it and ACX did the rest.

That was a week and three days ago

Today my audiobook is live on Audible! It is on there for £14.49 – the price being set by Audible, though it’s fairly arbitrary as most people use credits and most books, including mine, cost 1 credit. It’s also on iTunes for £7.95.

My completed ACX project

My completed ACX project