[PD] FM feedback synthesis issue

mami music mami.music at gmail.com
Tue Mar 7 20:46:13 CET 2006


HI to all... yes i´m using the s~ and r~ objects, and im not using the
block~ object. Here is a copy of the patch so you guys can take a look at
it.... very simple as it is. Refering theoy is the computer music tutorial
by curtis roads.... Maby the delay is causing he strange effect of the pitch
shifting.... illl check with the block~ object....

#N canvas 275 190 454 304 12;
#X obj 175 138 osc~;
#X obj 230 157 s~ fb;
#X obj 174 67 r~ fb;
#X obj 174 87 *~;
#X obj 229 34 vsl 15 50 0 1000 0 0 empty empty feedback 0 -8 0 8 -262144
-1 -1 0 1;
#X obj 175 114 +~;
#X obj 284 61 vsl 15 50 20 1000 0 0 empty empty frequency 0 -8 0 8
-262144 -1 -1 1300 1;
#X obj 154 211 dac~;
#X connect 0 0 1 0;
#X connect 0 0 7 0;
#X connect 0 0 7 1;
#X connect 2 0 3 0;
#X connect 3 0 5 0;
#X connect 4 0 3 1;
#X connect 5 0 0 0;
#X connect 6 0 5 1;




thankz for your help

daniel


2006/3/7, Roman Haefeli <reduzierer at yahoo.de>:
>
> hi daniel
>
> can you tell us where you found the referring theory? does the theory
> mention the delay in the feedback line? since you only can achieve a
> feedback loop by using a [s~]/[r~]-pair you normally get a delay of 64
> samples in pd.you can de-/increase this value by setting a different
> block size with the object [block~]. i can only assume, but i think in
> such an unstable system the delay may plays an important role.
>
> roman
>
>
> On Mon, 6 Mar 2006 12:33:23 -0500
> "mami music" <mami.music at gmail.com> wrote:
>
> > Hi.
> > im simulating  single carrier FM feedback. Im modulating the pitch of an
> > osc~ with it´s own output:
> > *Im multiplying the output of the osc~ with a fader that goes from 0 to
> > 1000.
> > *Thar result im adding with a fixed frequency.
> > *and then back to the main freq of the osc~ object
> >
> > this is very simple, according to theory i should get an increase in the
> > partials (which im getting), but im also getting a pitch shift in the
> main
> > freq of the oscilator as i expand the amplitude of the feedback!!!
> > I can´t see why this is happenig, i think it is not supposed to happen.
> Can
> > ayone explain to me why this is happening and how can i avoid it?
> >
> > thankz
> >
> > daniel gomez
> >
>
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