Inspired by recently playing with an analog virtual synth that apparently uses non-linear filters I was looking at what might function similarly in Csound. Unfortunately only found three obvious choices. Neither nlfilt nor nlfilt2 seemed like great candidates, frankly the parameters seem unintuitive & over my head, I'm used to more standard filter settings like cutoff, Q etc.
And sadly the one I really wanted to try, svn, has not implemented in the rarely updated Csound for Android.
Are there any other options I'm missing here? Some filters are not designated as linear, some are, so I'm not really sure.
I noticed in the virtual analog synth, like the svn opcode, there is a drive control in the filter itself. Would using a hyperbolic tangent distortion like the distort1 opcode before the mvclpf4 be likely to have any effect such as increasing the non-linearity of the filter as it does with the svn?
It would be slightly different as the nonlinearity inside the filter is within the internal feedback delay paths etc, but it should do something.
For the moogladder etc, driving the filter harder (e.g. putting a hotter signal, then
perhaps attenuating the output if needed) would have a similar effect to the svn drive
control. Also the resonance can go beyond 1
for crunchier high res sounds.
Prof. Victor Lazzarini
Maynooth University
Ireland