Make your audiobooks
ACX-compliant.
Automatically.
Drop in your chapters. Get back files that pass every ACX quality check -- levels, peaks, noise floor, format. No guesswork. No DAW required.
Drag & drop your audio files here
WAV, MP3, FLAC -- up to 500 MB
Accepted formats: WAV, MP3, FLAC. Maximum file size 100 megabytes.
How it works
Upload your files
Drop in your WAV, MP3, or FLAC chapters. Process one file or an entire book.
We handle the rest
Our engine adjusts levels, peaks, noise floor, and formatting -- 9 steps, fully automatic.
Download compliant audio
Get back CBR MP3s that pass every ACX quality check. Ready to upload to ACX.
What ACX requires
Your files need to hit these specs. We handle all of it.
-23 to -18 dBFS
RMS Level
Each chapter's average loudness must land in this range. Consistent chapter-to-chapter.
Below -3 dBFS
True Peak
No inter-sample peak above -3 dBFS. Our two-pass limiter catches every transient.
Below -60 dBFS
Noise Floor
Room tone must stay below -60 dBFS. We gate silence gaps and fill with shaped noise.
MP3 192 kbps CBR
Output Format
Mono MP3 at 44.1 kHz. We resample, downmix, and encode from any input format.
0.5 -- 5 seconds
Head & Tail Silence
0.5--1s at the start, 1--5s at the end of each chapter. We pad and crossfade automatically.
8 checks per file
Verified Before Export
Every file must pass all 8 ACX checkpoints before export. If a check fails, you'll know why.