Why ACX Keeps Rejecting Your Audiobook

If ACX keeps rejecting your audiobook files, it’s usually not because your narration is bad—it’s because of very specific technical issues like noise floor, peak levels, or inconsistent audio. The frustrating part is that these problems are not always obvious, even after hours of editing.

Many authors come to me after spending days trying to fix one chapter, only to have their files rejected again.

Why this happens

ACX has strict technical requirements and it can be hard to know how to measure all these figures let alone fix them.

• RMS (volume range) 23dB and -18dB

• Peak levels - 3dB peak

• Noise floor (background noise) 60dB noise floor

  
  

Even if your audio sounds “fine” to you, it can still fail their automated checks.

The real problem

Editing audiobook audio is not just about making it sound “clean.

”It’s about balancing technical compliance with natural, listenable sound.

That’s where most DIY attempts break down.

They can lead to:

• Overprocessed audio

• Loss of warmth and natural tone

• New technical issues introduced unintentionally

How I fix it

I work with authors to:

• Correct ACX technical issues (so files pass the first time)

• Remove distracting sounds like mouth clicks and background noise

• Maintain a natural, consistent tone across chapters

  
  

A quick example

Many clients come to me after spending hours trying to fix:

“noise floor too high” or “audio not within ACX standards”

In most cases, the issue can be identified and corrected quickly—but only if you know what to listen for and are familiar with the various tools that can correct it.

Want to know what’s wrong with your audio?

You don’t have to guess.

Send me a short sample (5-10 minutes), and I’ll tell you exactly what’s causing the issue. If I can correct it you'll have a free sample of what I can do.