Audience
Audiobook narrators, indie authors narrating their own books, audiobook producers and post-production studios preparing files for Audible ACX
About chapterpass
Audible's ACX has eight technical checkpoints, and a file that misses one comes straight back. chapterpass masters each chapter file to spec: RMS loudness between -23 and -18 dBFS, peaks held below -3 dBFS, a noise floor under -60 dBFS RMS, room tone at the head and tail, and a 192 kbps CBR MP3 on the way out. Every output is verified against the full spec before download, and you see the measured value next to the requirement for each checkpoint. The processing runs in your browser through WebAssembly, so your audio never leaves your device. There is no account to create. Your first file is free, then $36 per finished hour, $27 from 5 hours, $18 from 10 hours, billed by the second. A free measurement page at /free-acx-check reads your loudness, peak, noise floor and silence padding against the spec without mastering anything. chapterpass masters the measurable technical specs. It does not edit your recording, remove noise, or fix narration.
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Pricing
Starting Price:
$36 per finished hour
Free Version:
Free Version available.
Integrations
No integrations listed.
Company Information
chapterpass
Founded: 2026
Italy
chapterpass.com
Videos and Screen Captures
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