Karlsen Filter

[Eska]

Ove Karlsen lowpass from the music-dsp archive.
http://www.esnips.com/doc/bd44d12d-313d-4c05-aae0-fce8f751f5bc/Karlsen-filter

skol

[TomC]

Ove Karlsen lowpass from the music-dsp archive.
http://www.esnips.com/doc/bd44d12d-313d-4c05-aae0-fce8f751f5bc/Karlsen-filter

skol

"The requested resource (/doc/bd44d12d-313d-4c05-aae0-fce8f751f5bc/Karlsen-filter) is not available."

Tom

[Eska]

Mhh..No problem here (with firefox2).

[sunsynth]

Thanks 4 sharing Eska...

btw: DL works with IE but not with my Opera...

SUNsynth

[TomC]

Thanks 4 sharing Eska...

btw: DL works with IE but not with my Opera...

SUNsynth

Works here now, too.


Tom

[infuzion]

Nifty! What is the advantage of using this filter compared to others?
Boosting the Res high seems to make the filter fold over itself.

BTW, SM will round off "2*(PI)3.14159265358979*10000" to 62831.9
Helps with the Res folding slightly, so there you have it.

edit: looking at your Code, I see this:

Code: Select all

streamin in;
streamin cutoff;
streamin q;
streamin cor;
streamin f;
streamin track;
streamout out;
float resoclip,buf1,buf2,buf3,buf4,cut,res;
//cor=2*(PI)3.14159265358979*10000/sr;
cut=max ((f*track+cutoff)*cor,0);
cut=min (cut,0.7);
res=3*q;

resoclip = buf4;
resoclip = min(resoclip,1);
resoclip = max(resoclip,-1);
in = in - (resoclip * res);
buf1 = ((in - buf1) * cut) + buf1;
buf2 = ((buf1 - buf2) * cut) + buf2;
buf3 = ((buf2 - buf3) * cut) + buf3;
buf4 = ((buf3 - buf4) * cut) + buf4;

resoclip = buf4;
resoclip = min(resoclip,1);
resoclip = max(resoclip,-1);
in = in - (resoclip * res);
buf1 = ((in - buf1) * cut) + buf1;
buf2 = ((buf1 - buf2) * cut) + buf2;
buf3 = ((buf2 - buf3) * cut) + buf3;
buf4 = ((buf3 - buf4) * cut) + buf4;
out = buf4;

Is the second section a way to cascade filters, or did you accidentally copy & pasted twice?

[rl]

Guess it's ment to be 2x oversampling.

[Eska]

Thx RL. I think it`s oversampling. Sounds nice for the load anyway.

[infuzion]

Guess it's ment to be 2x oversampling.

Hmmm. I thought oversampling took two calculations & averaged the 2? This code re-uses the old variables (buf1-4), keeping their old values, so it looks like cascading to me. Maybe I don't understand oversampling.

[Eska]

For shure it is me. Thank you for explanation.

[exonerate]

Guess it's ment to be 2x oversampling.

Hmmm. I thought oversampling took two calculations & averaged the 2? This code re-uses the old variables (buf1-4), keeping their old values, so it looks like cascading to me. Maybe I don't understand oversampling.

yeah it's cascaded, i though it was oversampling at first but it's not.

If you comment out the second part, you can clearly hear it has less steep a cutoff.

The track knob on this doesn't seem to 'track' at all in fact i need to have that at zero for the cutoff knob to even work.

I'm going to have a play with it now, most likely I'll change it so the filter is set out like the state variable (using pitch to freq ect..) so that it can just be dropped inside the SV filter.

cheers

Exo

[infuzion]

I'm going to have a play with it now, most likely I'll change it so the filter is set out like the state variable (using pitch to freq ect..) so that it can just be dropped inside the SV filter.

That is a cool idea!
TIA

[exonerate]

ok here is my state variable compatible version

http://www.box.net/shared/xh9oa42976

It only needed a slight modification for it to work inside the SV filter,

And now the track knob works

When i get a chance i might take a look over at the dsp archive and see if theres any more filters that need SM'ing

---edit--- forgot to mention i turned the resonance down slightly, 'q' was multipied by 3, i just changed that to 2.5, i think it sounds a bit better.

cheers

Exo

[infuzion]

ok here is my state variable compatible version
http://www.box.net/shared/xh9oa42976
...
---edit--- forgot to mention i turned the resonance down slightly, 'q' was multipied by 3, i just changed that to 2.5, i think it sounds a bit better.

That's handy, thanks! Had to install the .9 beta though to open it.

Doing an A/B of the other LP filter, the Karlsen seems much quieter. I think maybe it is the res multiplication; in the SV version, the res code is:

Code: Select all

rez = 1.0 - resonance;

WhenI change the Karlsen code to

Code: Select all

res=.3*q;

it is much louder.

[exonerate]

That's handy, thanks! Had to install the .9 beta though to open it.

doh!! i keep forgetting I'm using the beta version.

cheers

Exo [/url]