Using Declipper 

 

Declipper repairs digital and analog clipping artifacts that result when A/D converters are pushed too hard or magnetic tape is over-saturated. Declipper can be extremely useful for saving recordings that were made in a single pass, such as live concerts or interviews, and any audio that cannot be re-recorded.

 

Choosing a Declipping Mode

In most cases, it is best to start with the Declipper module's Single-band mode. For trickier clipping, you may need to use Multi-band mode (or Multi-resolution mode in RX Advanced). See below.

 

Using the Histogram to set the Clipping Threshold

The histogram meter in the Declipper module allows you to set the Clipping Threshold control by finding the audio level where the waveform's peaks are concentrated. This usually indicates at what level clipping is present in the file.

Select a section of the recording where clipping is prominent, then click the Compute button. This will analyze the levels of the program material. If clipping is present in the selection, it will usually appear as a horizontal line in the histogram that extends all the way across the meter.

To set the module's threshold, move the red line in the histogram, or the Clipping Threshold slider, until the red line in the histogram is just below the line where clipping is concentrated.

 

Makeup Gain

Start by setting make-up gain at around -6.0 dB. This control accommodates the increased peak levels caused by the declipping process. If you're removing clipping during a short selection of a file, you may want to set this control higher to prevent a noticeable volume drop in the program material during the declipped section.

 

Choosing a quality mode

There are three quality modes in RX's Declipper: Low, Medium, and High. Low quality mode processes very quickly; High quality mode processes slowly but in some cases can achieve better results. In many cases you will find that "Low" quality mode gives you great results. To save time, always start by previewing the Low quality modes first.  

 

When to use Special (multi-band and multi-res) modes

Usually, Single-band mode is a good start for any audio file, but if the quality of single-band declipping is insufficient, you may want to try other modes, such as Multi-band or Multi-resolution declipping. They have similar parameters, but you can select the number of frequency bands to perform interpolation. A higher number of bands does not necessarily mean higher quality. You may need to search for a good sound with this parameter. For most audio files, Single-band mode will give best results, but in some rare cases other modes may sound better. For example, use of multi-resolution mode can be used in certain scenarios like high female vocals with reverberation that have only a moderate amount of clipping. We recommend you try multiple modes and preview the results in the Compare Settings window.

 

Read more about Declipper controls in the Reference Guide.