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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.<br>
<div class="moz-cite-prefix"><br>
Let's stay in touch about this. It sounds like a fun project.<br>
<br>
<br>
happy new year<br>
<br>
On 12/31/2014 02:11 PM, Alexandre Torres Porres wrote:<br>
</div>
<blockquote
cite="mid:CAEAsFmhMpfyCzCpZh70o5gSYq__DG=TibzrNP=mg+STo_FSdHg@mail.gmail.com"
type="cite">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<div dir="ltr">> <span style="font-size:12.8000001907349px">Miller
(being the author) would know better</span>
<div><br>
</div>
<div>But the [moog~] object that I see here on Pd extended was
written by gunter Geiger.</div>
<div><br>
</div>
<div>> <span style="font-size:12.8000001907349px">it would be
super cool to have this as a Pd</span></div>
<div><span style="font-size:12.8000001907349px">> abstraction
rather than an extern.</span></div>
<div><span style="font-size:12.8000001907349px"><br>
</span></div>
<div><span style="font-size:12.8000001907349px">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 list.</span></div>
<div><span style="font-size:12.8000001907349px"><br>
</span></div>
<div><span style="font-size:12.8000001907349px">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.</span></div>
<div><span style="font-size:12.8000001907349px"><br>
</span></div>
<div><span style="font-size:12.8000001907349px">cheers and happy
new year.</span></div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">2014-12-31 19:42 GMT-02:00 David Medine
<span dir="ltr"><<a moz-do-not-send="true"
href="mailto:dmedine@ucsd.edu" target="_blank">dmedine@ucsd.edu</a>></span>:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF"> Cool, I will
definitely check out this SC object. Thanks for that.<br>
<br>
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. <br>
<br>
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.<span
class="HOEnZb"><font color="#888888"><br>
<br>
-David</font></span>
<div>
<div class="h5"><br>
<br>
<div>On 12/31/2014 10:05 AM, Alexandre Torres Porres
wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Hi David, <br>
<br>
> <span style="font-size:12.8000001907349px">It'd
certainly be interesting to see an what actual
implementation</span>
<div><span style="font-size:12.8000001907349px">>
of this does, rather than just some matlab
plots.</span>
<div><br>
</div>
<div>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. </div>
</div>
<div><br>
</div>
<div>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.</div>
<div><br>
</div>
<div>Cheers</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">2014-12-29 17:20
GMT-02:00 David Medine <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:dmedine@ucsd.edu"
target="_blank">dmedine@ucsd.edu</a>></span>:<br>
<blockquote class="gmail_quote" style="margin:0
0 0 .8ex;border-left:1px #ccc
solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF"> I
believe, though I may be wrong, that the
Moog vcf object is based on the algorithm
described in the 2004 Huovalainen paper
(citation [6] in the Fontana):<br>
<a moz-do-not-send="true"
href="http://www.mirlab.org/conference_papers/International_Conference/DAFx%202004/Proc/P_061.pdf"
target="_blank"><br>
http://www.mirlab.org/conference_papers/International_Conference/DAFx%202004/Proc/P_061.pdf</a><br>
<br>
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.<br>
<br>
Still, judging by the plots they provide,
they seem to have overcome the frequency
warping issue (an artifact of unit delay)
described by Huovalainen. <br>
<br>
It'd certainly be interesting to see an what
actual implementation of this does, rather
than just some matlab plots.<br>
<br>
-David<span><br>
<br>
<br>
<div>On 12/28/2014 07:43 PM, Alexandre
Torres Porres wrote:<br>
</div>
</span>
<blockquote type="cite"><span>
<div dir="ltr">hi, do you know if the
moog object comes from this paper?
<div><br>
</div>
<div><a moz-do-not-send="true"
href="http://quod.lib.umich.edu/cgi/p/pod/dod-idx/preserving-the-structure-of-the-moog-vcf-in-the-digital.pdf?c=icmc;idno=bbp2372.2007.062"
target="_blank">http://quod.lib.umich.edu/cgi/p/pod/dod-idx/preserving-the-structure-of-the-moog-vcf-in-the-digital.pdf?c=icmc;idno=bbp2372.2007.062</a><br>
</div>
</div>
<br>
<fieldset></fieldset>
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