dmedine at ucsd.edu
Wed Dec 31 23:57:21 CET 2014
Sorry, I was thinking of one that Miller wrote that I saw sometime back.
I haven't actually looked at the one on extended. I will check it out.
Let's stay in touch about this. It sounds like a fun project.
happy new year
On 12/31/2014 02:11 PM, Alexandre Torres Porres wrote:
> > Miller (being the author) would know better
> But the [moog~] object that I see here on Pd extended was written by
> gunter Geiger.
> > it would be super cool to have this as a Pd
> > abstraction rather than an extern.
> Dan Wilcox also wanted that as I remember. If you care to help me we
> could try and do it. I kinda suck at math and all but when I put my
> mind into it I can do these things I never knew I could :) I've been
> implementing several filters with [fexpr~] and/or vanilla's raw
> pole/zero filters. I've kinda done them all, [moog~] is the next on my
> But I probably won't get into this until the 2nd half of january, as I
> plan to go to some island for my summer break.
> cheers and happy new year.
> 2014-12-31 19:42 GMT-02:00 David Medine <dmedine at ucsd.edu
> <mailto:dmedine at ucsd.edu>>:
> Cool, I will definitely check out this SC object. Thanks for that.
> Miller (being the author) would know better than I of course, but
> I believe the way that [moog~] works is to use Runge-Kutta to
> solve the ordinary differential equation that governs each stage
> of the filter in its continuous time representation. This equation
> (along with a discrete implementation of the complete filter) is
> what is described in the paper I mentioned. Incidentally, using
> Runge-Kutta (or any appropriate iterative ODE solver) also
> abnegates the frequency warping problem.
> I think it might be very difficult to code this up with [fexpr~].
> It would certainly require at least a quadrupling of the sampling
> rate. Has anyone out there ever implemented Runge-Kutta with
> [expr~]? It might also be that Pd's data structures are an
> appropriate choice for such a project? Either way, it would be
> super cool to have this as a Pd abstraction rather than an extern.
> On 12/31/2014 10:05 AM, Alexandre Torres Porres wrote:
>> Hi David,
>> > It'd certainly be interesting to see an what actual implementation
>> > of this does, rather than just some matlab plots.
>> An actual implementation is provided in the MoogFF filter in
>> Super Collider, you can just download and try it out. The code of
>> the object is also provided somewhere, as it is a source code.
>> I'd like to understand pd's [moog~] object one day, and implement
>> it with [fexpr~] or something. Maybe I'll do this other one as well.
>> 2014-12-29 17:20 GMT-02:00 David Medine <dmedine at ucsd.edu
>> <mailto:dmedine at ucsd.edu>>:
>> I believe, though I may be wrong, that the Moog vcf object is
>> based on the algorithm described in the 2004 Huovalainen
>> paper (citation  in the Fontana):
>> I am a little confused here (in the Fontana) by the author's
>> assertion that he can implement a 'delay-free' loop by
>> computing the output first, and then finding the states of
>> the filter based on this. I don't quite see how this is
>> different from finding the states first and then finding the
>> output -- chicken then the egg vs. egg then the chicken.
>> Still, judging by the plots they provide, they seem to have
>> overcome the frequency warping issue (an artifact of unit
>> delay) described by Huovalainen.
>> It'd certainly be interesting to see an what actual
>> implementation of this does, rather than just some matlab plots.
>> On 12/28/2014 07:43 PM, Alexandre Torres Porres wrote:
>>> hi, do you know if the moog object comes from this paper?
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