Audible.com Mastering Requirements Help

Discussion in 'Mastering' started by kenhall, Jul 3, 2013.

  1. kenhall

    kenhall Active Member

    I am producing an audiobook for audible.com in my home studio. This is my first one and I am new to this forum, so advance apologies if I am posting in the wrong forum.

    Audible has the following instructions on their web site:

    [h=1]Mastering Guidelines[/h]
    Once the book is fully edited and QC’d, it should be mastered. Mastering is the process of adjusting the sound to make it more even and "listenable"
    [h=2]Mastering:[/h]Your submitted files should measure between -23dB and -18dB RMS, with peaks hovering around -3dB. Your noise floor should fall between -60dB and -50dB.
    To make the audiobook levels louder and more-even throughout is vital. Typically, this process is achieved by RMS normalization around -20db, or compression/limiting. Compression should be applied with a fast attack and release, around a ratio of 3:1. A hard limiter may also be used, and audiobooks are EQ’d during this time, to sweeten the sound and make it more pleasing to the ear. Often, muddled low end and mid-range is cut to make the audiobook sound more clear and smooth.

    ​Questions:

    1) Would somebody kindly interpret this for somebody who is new to these concepts
    2) I am currently using GarageBand on a MacBook Pro and suspect that I need some beefier software like Logic Pro to meet these requirements
    3) Does the mastering process occur after the recording is done and quality checked using software like Audacity, etc.?

    Thanks so much.

    Ken


     
  2. hueseph

    hueseph Well-Known Member

    RMS= Root Mean Square. It's a complicated formula. It's like an average loudness but not exactly. It's like an average loudness not including the peaks. The peaks are...well...the peaks. Watch your volume meter. for the most part they want the sound to hover around -23 and as high as -18dB. The sound can go lower but no higher than -3dB at it's peaks. These should be clearly marked on the master volume meter. Garageband should be perfectly fine. If you need to you can look for free metering plugins. Try http://www.lsraudio.com/lvlmeter.html , http://www.voxengo.com/product/span/

    Span is particularly good. It has both a detailed meter and a spectral analyzer.

    Both of the above plugins are free.
     
  3. DaleVO

    DaleVO Active Member

    Ken,
    I hope this helps.
    Dale
     
  4. hueseph

    hueseph Well-Known Member

    It seems that audible is looking for pre-mastered files. Limiting and normalization are applied during mastering. Do not limit your file. They want control over how the file is mastered and limiting your files at this point may prevent them from achieving their goals.
     
  5. kenhall

    kenhall Active Member

    Outstanding responses, and in English too. Thanks for translating this new language for me. I look forward to learning more because it is extremely fascinating.
     
  6. DaleVO

    DaleVO Active Member

    I have not recorded for Audible. However, I found it surprising that they would want the talent to provide a mastered file.
    +1 on Hue's advice. Leave them the headroom to work.
     
  7. bouldersound

    bouldersound Real guitars are for old people. Well-Known Member

    My interpretation is that the -3dBFS peaks and -20dBFS or so RMS are intended to be the final levels and no further processing will be done by Audible.com.
     
  8. DaleVO

    DaleVO Active Member

    Agreed Boulder. I found the info that the Ken posted, and see that they want the files delivered in 192Kbps, MP3 format. So by their explanation, "mastering" is up to the VO talent. It is my standard M.O. to do some of those tweaks, as needed, while editing, and I never considered that as "mastering", just editing the mix.
     
  9. kenhall

    kenhall Active Member

    Apologies for not including the source link duh
     
  10. kenhall

    kenhall Active Member

    Did it again!

    Here's the source link: Rules for Audiobook Production

    Ken
     
  11. bouldersound

    bouldersound Real guitars are for old people. Well-Known Member

    From that link:

     
  12. hueseph

    hueseph Well-Known Member

    Yeah. I read that all wrong. My bad.
     
  13. bouldersound

    bouldersound Real guitars are for old people. Well-Known Member

    -20dBFS RMS does seem a little low by music mastering norms so I was a bit confused at first, but that does make sense since it's just voice rather than continuous full spectrum sound.
     

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