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fold back distortion

Type : distortion
References : Posted by hellfire[AT]upb[DOT]de

Notes :
a simple fold-back distortion filter.
if the signal exceeds the given threshold-level, it mirrors at the positive/negative threshold-border as long as the singal lies in the legal range (-threshold..+threshold).
there is no range limit, so inputs doesn't need to be in -1..+1 scale.
threshold should be >0
depending on use (low thresholds) it makes sense to rescale the input to full amplitude

performs approximately the following code
(just without the loop)

while (in>threshold || in<-threshold)
{
// mirror at positive threshold
if (in>threshold) in= threshold - (in-threshold);
// mirror at negative threshold
if (in<-threshold) in= -threshold + (-threshold-in);
}


Code :
float foldback(float in, float threshold)
{
if (in>threshold || in<-threshold)
{
in= fabs(fabs(fmod(in - threshold, threshold*4)) - threshold*2) - threshold;
}
return in;
}



Comments


Added on : 17/06/11 by nikolatesla20[ AT ]yahoo[ DOT ]com
Comment :
Sounds really good              



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