[Pd] Pd's biquad

Mon Jan 29 23:55:30 CET 2007

Hallo,
Chuckk Hubbard hat gesagt: // Chuckk Hubbard wrote:

> On 1/28/07, Frank Barknecht <fbar at footils.org> wrote:
> >Frank Barknecht hat gesagt: // Frank Barknecht wrote:
> >
> >> Actually I've just read a nice, not too mathematical explanation of
> >> biquad-filters in Perry Cook's book "Real Sound Synthesis for
> >> Interactive Applications" which I'm currently reading. It's a bit too
> >> expensive to buy just for the biquad pages, but maybe you can find it
> >> in a library.
> >
> >Uhm, and another one is here:
> >http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt
> 
> Thanks Frank.  I came across that one a few days ago, still not quite
> through it yet.  I'll see if our library has Perry Cook.

I just remembered, that Cook is a colleage of Julius O. Smith III and
recommends JOS for people who want to dig deeper into the math. And
the good thing is: JOS has a huge amount of texts online. 

One about biquads is here: 
http://ccrma.stanford.edu/~jos/filters/BiQuad_Section.html
then follow the links.

I played around a bit with the [biquad~] today and came up with
attached patch, which is similar to CH's patch. It's attached.

Ciao
-- 
 Frank Barknecht                 _ ______footils.org_ __goto10.org__
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with a (rectangular windowed) FFT. FFTs aren't properly introduced
until much later.;
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#X text 725 346 w(n) = x(n) + fb1 * w(n-1) + fb2 * w(n-2);
#X text 666 362 Syntax: biquad~ fb1 fb2 ff1 ff2 ff3;
#X text 739 300 2-pole-2-zero-filter;
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