Re: [PD] basic resonant filters in Pd

Good call! I explored the GGEE objects in Pd-extended, which led me to their source code (A+ for readability), which led me to this: http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt

Thanks for the pointer.

Cheers! ~Brandon

On Sun, May 17, 2009 at 9:53 AM, Derek Holzer derek@umatic.nl wrote:

I think if you Google "biquad filter coefficients" or similar, you'll come up with tons of Greek to play with. Otherwise, the GGEE objects merely do the calculations and export them as messages, so if you wanted to use these objects to get some reasonable sounding stuff and then build your vanilla filters based on those coefficients, the filters themselves are technically vanilla as well.

best! D.

brandon zeeb wrote:

...

Derek,

Thanks for the complete list! This is very helpful.

I was hoping to start off by using Vanilla-only objects. Does anyone have some good examples of how [biquad~] can be used to replicate standard low/high/band pass filters w/ q? Any other ideas?

~brandon

On Sun, May 17, 2009 at 4:35 AM, Derek Holzer <derek@umatic.nl mailto: derek@umatic.nl> wrote:

Hi Brandon,

here ya go!

VANILLA PD

*SIGNAL CONTROLLED*

vcf~ moog~

*MESSAGE CONTROLLED*

lop~ bp~ hp~ biquad

PD-EXTENDED/EXTERNAL LIBRARIES

*SIGNAL CONTROLLED*

---IEM Lib filters---

vcf_filter~ (building block for following abstractions)

vcf_bp2~ vcf_bp4~ vcf_bp6~ vcf_bp8~

vcf_hp2~ vcf_hp4~ vcf_hp6~ vcf_hp8~

vcf_lp2~ vcf_lp4~ vcf_lp6~ vcf_lp8~

vcf_rbp2~ vcf_rbp4~ vcf_rbp6~ vcf_rbp8~

*MESSAGE CONTROLLED*

---IEM Lib filters---

filter~ (building block for following abstractions)

bpq2~ bpw2~ bsq2~

hp1~ hp2~ hp2_bess~ (can go from 2-10 order) hp2_butt~ (can go from 2-10 order) hp2_cheb~ (can go from 2-10 order) hp2_crit~ (can go from 2-10 order)

lp1~ lp2~ lp2_bess~ (can go from 2-10 order) lp2_butt~ (can go from 2-10 order) lp2_cheb~ (can go from 2-10 order) lp2_crit~ (can go from 2-10 order)

---GGEE---

(Generate biquad coefficients) bandpass highpass lowpass

Maybe I missed some? ;-)

Best! D.

brandon zeeb wrote:

   Hallo,

   How does everyone implement basic resonant filters, ie: LPF,
   HPF, BPF, in Puredata?  [lop~], [hip~], and [bp~] are nice, and
   can easily be strung serially to create 2nd, 3rd, and 4th order
   filters, but lack q.

   [biquad~] seems up to the task, but I'm unable to find any
   information in the help file or docs online pertaining to how
   one could replicate standard filters using this object.

-- ::: derek holzer ::: http://blog.myspace.com/macumbista ::: http://www.vimeo.com/macumbista ::: ---Oblique Strategy # 164: "Twist the spine"

-- ::: derek holzer ::: http://blog.myspace.com/macumbista ::: http://www.vimeo.com/macumbista ::: ---Oblique Strategy # 76: "Give the game away"