Back to overview Documentation version 8.50


Delossifier section

The DeLossifier attempts to clean up the effects of lossy compressed (MP3 etc.) input.

Lossy compression (such as MP3 compression) reduces the amount of data needed to store or stream audio by 'throwing away' things that it deems 'nearly inaudible'. Especially at lower bitrates, this causes very clearly noticeable artifacts that are typical for lossy compression.

Beside the fact that these artifacts are often already noticeable, the processing that is done by Stereo Tool (or any other processor) invalidates the assumptions that the compressor has made on which effects are noticeable and which are not.

The DeLossifier attempts to detect these artifacts, and to clean them up.

Main panel

Attempts to remove pre-ringing from lossy compressed audio files.

One of the typical artifacts in MP3 and other lossy compressed files is pre-ringing. This means that a sound that should start suddenly, has a sort of 'pre-echo': Instead of starting suddenly you first hear it come up softly, and then there's a sudden jump when the sound was really supposed to start. This gives the typical 'smeared-out', non-punchy sound on lower bitrate MP3s.

This filter attempts to detect pre-ringing, and reduce it.

Important: Because to be able to determine whether a sound is caused by pre-ringing or it is a sound that should be there, this filter needs to look ahead a lot, which adds a lot of extra latency.

  • Delossifier
    Enables the Pre-Ringing Killer

Pre-ringing killer (big latency!) panel


  • Pre-ringing killer

  • Difference
    Plays only the sounds that are determined to be pre-ringing.

    If Left channel only (testing) is enabled, the pre-ringing sound is played on the left channel, and the audio on the right channel is unaffected. This makes it easy to hear if only pre-ringing is removed (the sounds stop at the moment when a kick is played), or more sounds are removed.

  • Hear

  • Maximum relative volume reduction
    Determines how strong the pre-ringing killer works.

    At 100%, the audio that is determined to be pre-ringing is removed completely. At higher levels, more audio is removed. This may cause 'gaps' before punchy sounds, but it also improves the dynamics further.

  • Left channel only (testing)
    For testing: Pre-ringing is only removed for the left channel.

    This also affects Difference.

Spectral hole filler panel


  • Spectral Hole Filler

  • Strength

  • Threshold

  • Detect MPEG

  • No reconstruction below

  • Do not reconstruct top part

  • Slow rise

  • Avoid highs flutter

  • Stronger flutter protection

  • Reconstruct top part

Input spectrum panel


  • Show histograms

Output spectrum panel