TerraTec Aureon 7.1 Universe Manual page 51

6. Descratcher
The Descratcher function effectively removes pops and crackling noises from old vinyl and
shellac records as well as from audio files in which the tone quality has been decreased
during recording because of switch noise, digital crosstalk or thyristor humming.
The Descratching algorithm consists of two components: the Declicking filter and the
Decrackling filter. While the Declicking filter is running, usually to remove relatively loud clicks
and pops from old vinyl records or switch noise from digital or analog audio devices, the
Decrackling filter removes any remaining, usually quiet but dense crackling.
The higher you set the Declick parameter, the more cracking noise is removed. When it is set
to 0, the filter lets through nearly all cracking noises. To remove cracking noises from soiled
vinyl records, a Declick value of about 50 is good in most cases.
A typical popping noise in a signal from a vinyl record (left) and the reconstructed signal (right).
The higher you set the Decrackle parameter, the more crackling noise is removed from the
original. The highest setting, nearly 100, dampens the actual input signal. In general, this
parameter can be set to 80 without resulting in any audible depletion of the original sound. In
some cases, an extremely high setting, even up to 100, can be used to improve the quality of
the audio material.
To minimize the depletion of the original sound in the Descratching procedure, you should
listen very carefully to the effects of the Declick and Decrackle parameters at various points of
the recording before deciding on their final values. In doing so, the Difference function in the
Playback area will certainly be a great aid. It allows you to set the parameters in a very
intuitive manner. With it, you can switch between the original input signal and the
input/output signal difference, i.e. the part that has been removed by the Descratching
algorithm. Normally, you do not want the signal difference to contain any part of the original
signal that you want to keep. For more notes on optimizing the settings of the Declick and
Decrackle parameters, see to the Application Notes.
Note also that the Difference functions can be applied to the Descratcher and Denoiser
functions simultaneously. If you want to run the Descratcher only, leave the sliders (threshold
and reduction) for the Denoiser set to 0.
SoundSystem Aureon 7.1 Universe (English) 51