[PD] FM problems

[matthijs at devdsp.net]

On Fri, Jul 18, 2003 at 10:20:02PM -0700, Matthew Allen wrote:
>  Sorry about the complexity.

No problem at all! The basic feedback was understandable (I *think*) and
I've already learned some things I didn't know from your patch
(canvases), which is good (and I'm going to be studying it some more).

>I am attaching 2 new files (as simple as
> possible illustrating the point). 

Ahem ... that's very friendly of you, except that they didn't make it to
my inbox somehow ;)

>I think it is normal PD behavior just to
> turn off the audio stream when you try and connect a straight audio feedback
> loop (which is why i was suprised you were getting PD to crash, I didnt
> really think it was a bad loop). NoWorks.pd is basically a straight feedback
> loop, it just stops producing audio when I connect it. 

Right - like I said, when I was preparing a simpler example patch that
had the feedback loop in the main patch instead of in a subpatch
connected to an outlet~, I also got silence instead of a crash. Which I
guess indicates a newbie problem with understanding FM or something ;)

> 
> Works.pd is even more interesting. Not using z~ or a delay (straight
> connections with z~ doesn't seem to work either) instead I am using a
> throw~/catch~ pair. 

throw~ and catch~ I've never heard of until today - I'll take a look at
them. What I specifically don't understand is what the difference is
between a throw~/catch~ setup and a simple send~ / receive~

>And this seems to work. In fact any time I try doing a
> feedback loop with connections I get the audio shutting off, but if I use a
> throw~ or send~ i am fine. My assumption here is that both of the remote
> sending objects have a 1 sample delay?

Well, if they did z~ 1 should work as well. As it stands, z~ gives
silence and throw/catch and send/receive work (see attached example
patch). Strange ... it's almost as if PD doesn't like an uninterrupted
feedback connection but thinks it's ok when there's no direct connection
or something.

Oh well ... I've now got three alternatives to make it work (delay,
send/receive, throw/catch) so that should be enough to "don't do that
then" 

> 
> either way it should help you come up with an acceptable solution to you
> problem.  
> 
> -----Original Message-----
> From: matthijs at devdsp.net
> To: Matthew Allen
> Cc: 'pd-list at iem.kug.ac.at '
> Sent: 7/18/2003 1:13 PM
> Subject: Re: [PD] FM problems
> 
> On Fri, Jul 18, 2003 at 09:49:38AM -0700, Matthew Allen wrote:
> 
> > To the original poster I have attached my work in progress 3-op FM
> synth.
> > Its uses z~ to give the users the ability to feedback any of the
> operators
> > to any other operator (including self feedback). You'll need Zexy of
> course
> > and IEMlibs for the interface.
> 
> Thanks a lot - it's *way* too complex for my meagre skills to
> comprehend, but I'll definitely study it.
> 
> But I think I messed up somewhere else as well, because when I was
> preparing a simple example patch to share with the list that was
> basically nothing more than the output of a phasor~ and the output of an
> osc~ added together feeding into cos~ and the output of that
> manipulating the frequency of the osc~ object, PD no longer segfaulted.
> Nor did it output sound, but at least this shows there's something else
> going on.
> 
> 
> > 
> > My Apologies to Miller for stealing the basics from his docs, and also
> to
> > Native instruments for stealing their idea for the Operator matrix. I
> have
> > been programming fm synths since the SY77 came out and I was amazed
> when I
> > first saw this implemented. It just makes sense.
> > 
> > The patch itself is still in pre-alpha. The synthesis works, I'm just
> > working on an interface. Use the bang in the upper left to send note
> and
> > velocity info (unless you have a midi keyboard, then just play the
> > keyboard). I have some random pitch stuff going on so don't thik that
> that
> > is broken, just look in [PD FM_Pitch]. Make sure and set both the
> > feedback/output matrix and the envelopes under them.
> > 
> > m.
> > 
> > 
> > 
> 
> 
> 
> -- 
> take care,
> 
> Matthijs de Jonge
> http://devdsp.net - news and resources for computer musicians
> 
> 
> _________________________________________________
> Scanned on 18 Jul 2003 20:13:15
> Scanning by http://erado.com

-- 
take care,

Matthijs de Jonge
http://devdsp.net - news and resources for computer musicians
-------------- next part --------------
#N canvas 171 205 634 463 10;
#X obj 169 215 phasor~;
#X floatatom 80 116 5 0 0 0 - - -;
#X obj 190 246 +~;
#X obj 189 269 cos~;
#X obj 185 296 *~;
#X obj 80 149 vsl 15 128 0 1 0 0 empty empty OUTPUTVOL 0 -8 0 8 -262144
-1 -1 4400 1;
#X obj 175 354 dac~;
#X msg 41 387 \; pd dsp 1;
#X msg 145 387 \; pd dsp 0;
#X text 56 424 ON;
#X text 165 424 OFF;
#X obj 226 319 s~ feedback;
#X obj 272 20 r~ feedback;
#X obj 359 67 vsl 15 128 0 1 0 0 empty empty feedbackvol 0 -8 0 8 -262144
-1 -1 3100 1;
#X obj 251 106 *~;
#X obj 249 360 throw~ fbline;
#X obj 157 18 catch~ fbline;
#X text 41 115 Freq;
#X obj 169 78 *~;
#X obj 62 22 vradio 15 1 0 2 empty empty throw/send 0 -6 0 8 -262144
-1 -1 0;
#X obj 85 85 abs;
#X text 6 21 throw;
#X text 7 37 send;
#X obj 247 76 *~;
#X obj 84 63 - 1;
#X connect 0 0 2 0;
#X connect 1 0 0 0;
#X connect 2 0 3 0;
#X connect 3 0 4 0;
#X connect 3 0 4 1;
#X connect 4 0 6 0;
#X connect 4 0 6 1;
#X connect 4 0 11 0;
#X connect 4 0 15 0;
#X connect 5 0 4 0;
#X connect 12 0 23 0;
#X connect 13 0 14 1;
#X connect 14 0 2 1;
#X connect 16 0 18 0;
#X connect 18 0 14 0;
#X connect 19 0 23 1;
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#X connect 20 0 18 1;
#X connect 23 0 14 0;
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