[PD] Re: [PD-announce] PWM in Pd

geiger geiger at xdv.org
Sun May 28 17:42:25 CEST 2006


On Fri, 26 May 2006, Hans-Christoph Steiner wrote:
> Even better would be to have a library of very handy objects like
> these written in Pd.  Then you wouldn't have to spend years learning
> digital audio to write your own.  Instead you could use ones that
> have been finely tuned and debugged.  And if you were interested, you
> could open them up and see how its done.

I agree ... one could start by going through the Pd
documentation, extract the examples in there and wrap them into
abstractions.

Günter



>
> .hc
>
> On May 26, 2006, at 4:27 PM, geiger wrote:
>
> >
> > Hi,
> >
> > nothing to do with PWM, but attached is a  bandlimited square and saw
> > implementation, based on the BF algorithm used in the BLOP plugins,
> > written in Pd only. The Pd documentation also has suggestions using
> > a BLEP
> > (band limited step function).
> >
> > The good thing about Pd is that you do not have to look for plugins
> > that
> > do the work, you can build them yourself using Pd's basic building
> > blocks.
> > I also have a BLIT (band limited impulse train) implementation of the
> > square wave lying around, and an implementation using integrated
> > wavetables. You can even do oversampling within Pd, so nothing really
> > keeps you from having bandlimited oscillators .. except that it
> > takes time
> > an knowledge to build them.
> >
> > Günter
> >
> > PS: the oscs need a great amount of tweaking and/or more tables.
> > something
> > to be done for the next version, but the idea should be clear.
> >
> >
> > On Thu, 25 May 2006 derek at x-i.net wrote:
> >> Hi HC,
> >>
> >> Hans-Christoph Steiner wrote:
> >>
> >>> I should say, I forgot that PWM was used in synthesis some, so I was
> >>> thinking about electronics and control when I was talking about PWM.
> >>> That's why my PWM objects are tailored towards, but should work
> >>> fine in
> >>> the audio context too, unless you need the wandering DC offset.
> >>
> >> But this is still not bandwidth-limited, is it? So it's use for audio
> >> would also be limited to situations where either you would use the
> >> PWM for
> >> controlling a "proper" audio oscillator, or where you don't really
> >> give a
> >> scheiss about aliased frequencies and audio birdies.
> >>
> >> I haven't checked your [square~] yet, but if it is antialiased it
> >> would
> >> fill a big missing void in PD's audio arsenal.
> >>
> >> Otherwise, I still suggest to use the BLOP plugins for LADSPA with
> >> [plugin~], which sound about as real as you can get, but still
> >> only seems
> >> to work under Linux.
> >>
> >> best,
> >> d.
> >>
> >> --
> >> derek holzer ::: http://www.umatic.nl
> >> ---Oblique Strategy # 177:
> >> "What is the reality of the situation?"
> >>
> >>
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>
>
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