Today I tested all three. With last two svf filters I don't see any
difference (I use ardour's built in plugin analyser), no noise.
The noisy fi.highpass (the first one) becomes closer to them as cutoff
freq goes higher, but still has different phase characteristics in lowest
part of it's spectrum (0 to ~20hz)
declare name "nstest";
import("stdfaust.lib");
import("filtersEOC.lib"); // I put
https://github.com/grame-cncm/faustlibraries/blob/master/filters.lib#L2611
part to this file (which is from EOC library)
process(x,y) = x,y : nl(drive, offsetL, fb, f, filter), nl(drive, offsetR,
fb, f, filter) with{
nl(drive, offset, fb, f, filter) = (+ : ef.cubicnl(drive, offset)) ~ *
(fb): (
_<:(fi.highpass(2, f), f2.svf.hp(f, 1/sqrt(2)), ( f2.svf2blti(f, 1/sqrt(2),
1) :ba.selectn(10,1)) ) : ba.selectn(3,filter)
);
filter = hslider("filter type",0, 0,3,0.5);
f = hslider("HPF freq",50,10,10000,0.01): si.smoo;
fb = hslider("feedback",0,-1,1,0.001);
drive = hslider("drive",0,0,1,0.001);
offsetL = hslider("offsetL",0,-1,1,0.001);
offsetR = hslider("offsetR",0,-1,1,0.001);
} ;
On Fri, Dec 18, 2020 at 9:10 PM Oleg Nesterov <o...@redhat.com> wrote:
> Hi Dario,
>
> this motivated me to look at your library again ;)
>
> On 12/18, Alik Rustamoff wrote:
> >
> > Hi, Dario, I, btw, ended up using blti filter from your edge of chaos
> > library. Good collection. No noises just does the job.
>
> Then I think that fi.svf.hp() should work equally well. Can you try it?
> See
> https://github.com/grame-cncm/faustlibraries/blob/master/filters.lib#L2611
>
> And this probably means that Dario was right, and the problem was caused
> by quantisation.
>
> Because IIUC in theory (and unless you modulate HPFfreq) these 3 filters
>
> fi.highpass(2, f)
> fi.svf.hp(f, 1/sqrt(2))
> svf2blti(f, 1/sqrt(2), 1) : ba.selectn(10,1)
>
> should have the same transfer function / impulse response.
>
> Oleg.
>
>
_______________________________________________
Faudiostream-users mailing list
Faudiostream-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/faudiostream-users
