Repairing a Distorted Audio Track

Description:

Have you ever been in the middle of a great sounding take, but suddenly the preamp or interface gets overdriven and the track is unusable? The De-clip module in RX can help rescue tracks that were recorded too hot by redrawing squared off waveforms.

Sample:

Here is an example of a vocal track where the preamp was overloaded.


Before RX:

After RX:

file
file

Plug-in Workflow:

  1. Select the distorted portions of the audio and open RX De-clip as an offline plug-in.
  2. Set the Threshold to identify where the De-clip algorithm should begin to apply processing. For this example, a threshold of –8.4 dB worked well.

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  3. Click Preview to hear the results. Adjust the threshold and quality settings as necessary.
  4. Once you’ve found the desired settings, click the Process or Render button to complete the repair.

Standalone Workflow:

  1. Open an audio file in the RX Audio Editor or send it using RX Connect.

  2. Select the distorted portions of the audio and open the De-clip module.
  3. Set the Threshold to identify where the De-clip algorithm should begin to apply processing. For this example, a threshold of –8.4 dB worked well.

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  4. Click Preview to hear the results. Adjust the threshold and quality settings as necessary.
  5. Once you’ve found the desired settings, click the Process button to complete the repair.

Tips: 

  • Adjust the Makeup Gain. In redrawing the waveform, the De-clip process causes an increase in peak levels. The Makeup Gain control can be used to prevent the signal from clipping after processing. It is also useful for matching the level after processing to unprocessed audio outside of the selection. As an extra measure of protection, engaging the Post-Limiter option applies a true peak limiter after processing to prevent the processed signal from exceeding 0 dBFS.
  • Adjust the quality. There are three quality modes in RX's De-clip module: Low, Medium, and High. The Low setting processes very quickly and was designed for times when the De-clip plug-in needs to be used as a real-time insert, and in many cases, you will find that the Low setting yields great results. The High setting processes more slowly but is capable of achieving better results and makes sense for rendered effects where latency and processing power is less of an issue.
  • De-link the threshold controls. If the clipping occurs only on one side of the waveform, or is more serious on one side than the other, you can de-link the Threshold sliders by clicking on the small chain icon between the top and bottom sliders.

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  • Zoom on the Histogram. Clipping can still occur on tracks with a low amplitude, and it can be hard to set the threshold and visualize the clipping on the Histogram with these tracks. The small + and – buttons to the left of the Histogram are designed to help with this. Click on these to change the amplitude scale and set threshold values as low as –64.0 dB.

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  • Not for brickwall limited audio! The De-clip interpolation is designed to help with analog and digital clipping but not brickwall limited audio. You can identify brickwall limiting visually; it does not display as a perfectly squared off waveform in the same way as clipping.

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  • Still hearing distortion? Read more about using the De-clipDe-crackleDeconstruct, and Spectral Repair tools to attack distortion problems in this recipe.

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