How to Verify Your Audio Files Are Acx Compliant Using Free Tools

March 16, 2026

By: Audio Scene

Ensuring your audio files are ACX compliant is essential for audiobook narrators and producers aiming to distribute their work on Audible and other platforms. Fortunately, you can verify compliance using free tools without the need for expensive software. This guide walks you through the steps to check your audio files effectively.

Understanding ACX Audio Requirements

Before verifying your files, it’s important to understand the key ACX requirements:

  • Audio format: MP3 with a bit rate of 192 kbps
  • Sample rate: 44,100 Hz (44.1 kHz)
  • Channels: Stereo
  • Peak levels: Between -3 dB and 0 dB
  • Background noise: Must be minimal and consistent

Tools Needed for Verification

You can use free tools like Audacity, MediaInfo, and online audio analyzers to check your files. These tools help verify format, sample rate, and peak levels.

Using MediaInfo

MediaInfo is a free program that provides detailed information about audio files.

  • Download MediaInfo from the official website.
  • Open your audio file in MediaInfo.
  • Check the format, sample rate, and channels.

Using Audacity to Check Peak Levels

Audacity is a free, open-source audio editor that allows you to view waveforms and measure peak levels.

  • Download and install Audacity.
  • Import your audio file.
  • Look at the waveform to identify peak points.
  • Use the “Amplify” or “Normalize” effect if necessary to adjust levels.

Using Online Peak Level Analyzers

Online tools like AudioCheck or Bear Audio Tool can quickly analyze peak levels without installing software.

  • Upload your audio file to the online analyzer.
  • Review the peak level readings.
  • Ensure levels are within the -3 dB to 0 dB range.

Final Tips for Compliance

After verification, make any necessary adjustments to your audio files. Re-check to ensure they meet all ACX specifications. Consistent audio quality and compliance improve your chances of approval and a better listener experience.

Using these free tools, you can confidently verify your audio files are ACX compliant and ready for distribution.