Will ACX reject your audiobook files? Check every chapter first
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R. S. Breed Founder
Audiobook files get rejected for technical reasons more than anything else. ACX's requirements, for example:
- Volume between -23 and -18 dB RMS
- Peaks below -3 dB
- Noise floor below -60 dB RMS
- MP3 at 192 kbps or higher, constant bit rate, 44.1 kHz
- Room tone at the start and end of each file, and no file longer than 120 minutes
The free checker measures every chapter file against ACX, Google Play Books, Kobo and Spotify for Authors before you upload: https://bervet.com/tools/audiobook-file-checker
Drop in your files and you get the numbers file by file, with a pass or fix against each platform. Each fix says what to change: use a limiter, re-export as constant bit rate, reduce background hiss, split a long file at a chapter break.
Your files are measured in your browser; nothing is uploaded. Free for members. INaudio (formerly Findaway Voices) keeps its requirements inside your account, so check those there.