[PD] Strange bug in my patch

Roman Haefeli reduzierer at yahoo.de
Fri Feb 26 09:47:27 CET 2010

The patch uses dynamic creation of objects and when dynamically creating
signal-processing objects or abstractions, the dsp graph is not
automatically recompiled (I hope I use the right words here).
Recompilation of the graph can be forced by switching dsp off and on
again. This is a known issue and has been discussed on the list. I can't
recall if it is considered a feature or a bug, but probably it doesn't
matter, since dynamic object creation is not officially supported). 

On Thu, 2010-02-25 at 21:23 -0800, William Brent wrote:
> I think I can get you a step closer to finding your problem...  If you
> run Pd in its 1st debug mode (pd -d 1), you'll see posts showing that
> creating or deleting an object quickly deactivates/reactivates DSP.
> So once you've loaded your sound file, set parameters and clicked
> "Start", manually toggling DSP on, off, then on solves the problem as
> well.
> I didn't put in the time to see why DSP needed to be toggled in that
> way for your particular case though.  Can you think of anything in
> your patch that might be linked to something like that?  Just a guess
> (I haven't chased down all your sends and receives), but since this is
> isolated to cases where density equals 1, it seems pretty likely a
> patching logic bug is preventing a parameter from getting to a DSP
> object until after the Start button is pushed.  Then, re-initializing
> DSP is refreshing that object's settings and all is well.

Actually, when creating a tilde object or an abstraction, that processes
signals, dynamically it's not taken into account for the currently used
dsp graph. However, when you create the second instance (or any other
tilde object), the first one is taken into account, but not the second.
So even if it seems to work for densities > 1, you actually hear only
n-1 instances. 


> Hope it helps,
> William
> On Thu, Feb 25, 2010 at 6:58 PM, Caio Barros <caio.barros at gmail.com> wrote:
> > Hi,
> > I'm working in this patch for a composition of mine but I keep getting a bug
> > and don't know what is wrong.
> > What my patch does is to load sound files and play them back at random
> > intervals of time. If you load enough samples, it can create a very dense
> > and granular sound texture, hence the name Texgen (texture generator). When
> > I load a sample I can control the minimum and maximum interval between
> > attacks, degree of tranposition (or pitch shift) and the density of the play
> > back wich is just how many times the same sample is loaded so it can be
> > played more times simultaneously.
> > The problem I'm having is that when I load a sample with density = 1 the
> > sound doesn't comes out and, that's the strange part, if a creat and object
> > like, say, a bang button and delete it, the sound magicaly pops out of the
> > loudspeakers.
> > I know this is a little inconvenient thig to ask, but can someone help me? I
> > don't know where else i could look for help.
> >
> > I attached the patch in this e-mail, and it can be also downloaded here:
> > http://puredata.info/Members/caiobarros/texgen/
> > together with a sound for testing it. Just put everything in the same folder
> > and it should work exept for this bug.
> >
> > Again sorry for any inconveniences, and thanks for the help.
> >
> > Caio Barros
> >
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> >

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