[PD] pd book sprint

Alexandre Porres porres at gmail.com
Mon Mar 30 20:41:56 CEST 2009


well, I totally agree with you, and that is why my stuff does not fill in
the niche of Miller's and others at all.
My stuff is for people who really had never seen anything like this, which
is practically everybody in brazil :)

I try to put some stuff in miller's book more accessible, but most of it I
dont even bother to attempt that at all! Just the basics...

The stuff is kinda in between Floss Manuals and Miller's book. But I dont
wish to inject the things I wrote about inside Floss Manuals at all. it
would even be smart to repeat some stuff redundantly.

But the theory in DSP we are discussing here is really minimum, and the math
could not be any simpler, which is just the procedure of using a [+] object,
as complex as adjusting the gain with [*].

Since it is that basic, I dont find it intimidating at all.

But I really hope we could all share our thoughts and ideas, and create
different materials that complement each other, and that are also coherent
with each other.

So sorry if I looked too technical, but I still believe it could be simply
presented, and that the material could benefit from it.

You see, DC Offset is also important to create Synthesis Control, like in
the Amplitude Modulation example. If you want to do an AM synth with [osc],
you need to adjust DC. But the procedure is really really simple. I will
work on the examples and send it to you as soon as i can.

thanks
alex


On Mon, Mar 30, 2009 at 3:29 PM, Derek Holzer <derek at umatic.nl> wrote:

> I agree with the principles of this approach, but perhaps not the
> complexity. The FLOSS Manual doesn't exist as a way to teach DSP. That's
> what Miller's stuff is for. It exists as a way to get people who are put off
> by the existing documentation, which is very very heavy in math, DSP and
> computer science. These are the people I get in my workshops every time.
> They just want to get an idea of how to do things and not be intimidated.
> Thus the emphasis on simple solutions rather than "correct" ones.
>
> If people are ready for a deeper understanding of DSP, that's where
> Miller's book, and pd-tutorial.com and the Roads CMT book and all the rest
> come in. And perhaps your Portuguese one as well. I don't want this book to
> step into a niche which already has many options, I want it to fill a niche
> which is still wide open: Pd for absolute beginners, no prerequisites
> required.
>
> D.
>
> Alexandre Porres wrote:
>
>> you know, yeah, but the thing is that phasor is not actually an oscilator
>> at all !!!
>>
>> the name actually refers to phase, and not sawtooth.
>>
>> Apart from [osc~], oscilators in puredata are basically wavetable
>> oscilators. You have objects such as [tabosc4~] and that is it.
>> What [phasor~] was designed to do is to indicate the phase of the waveform
>> on a table. So you have to adjust phsor to be compatible with the table
>> size. You do that simply by multiplying phasor (wich ramps up to one) to the
>> table size. So what it is meant to do is tell the position (or "phase") in a
>> table. That is why it goes from 0 to 1. If it did go from -1 to 1, as an
>> ocilator, then it wouldnt work that way.
>>
>> So there is a misconception of [phasor~] being a sawtooth wave generator
>> that can be misleading. As an oscilator, [phasor~] has a DC Offset. In order
>> to [phasor~] became an oscilator with no DC Offset, we have to correct it.
>>
>> Maybe it is nice to be explicit about it in Floss Manuals, and say that Pd
>> mostly works out with Table lookup oscilators, and that [osc~] is a special
>> and unique object that is meant to be a Cosine wave oscilator.
>>
>> Then, when explaining how to get other kinds of wavefroms on Pd, such as
>> sawtooth, square, triangle, we could emphasize that we are creating them,
>> and building them up with the objects we have. Thast also makes it implicit
>> that there is more than one way to di it, and that there is no official or
>> built in Square wave, for instance.
>>
>> I actually talk a lot about that on my book. And I present examples on how
>> to get a triangle waveform on a table using the sinesum comand, that is, by
>> summing up harmonics.
>>
>> Cheers
>> Alex
>>
>> On Mon, Mar 30, 2009 at 3:02 PM, Derek Holzer <derek at umatic.nl <mailto:
>> derek at umatic.nl>> wrote:
>>
>>    Is it really DC offset when the value goes from 0 to 1 instead of -1
>>    to 1? I mean, that's the way [phasor~] comes right out of the box.
>>
>>    D.
>>
>>    Alexandre Porres wrote:
>>
>>
>>        I tried again, and now it works much better than before... so I
>>        guess there was something wrong before.
>>
>>        Well Claude, it seems it almost works as the [triangle~] object.
>>
>>        Do you guys know about this one? It comes in some external library.
>>
>>        Were you who did it anyway Claude? :)
>>
>>        [triangle~] works in a similar fashion, it goes smoothly from
>>        inverse sawtooth to triangle and the sawtooth depending on the
>>        parameter (from 0 to 1).
>>
>>        The thing is that Triangle corrects the DC Offset, which could
>>        easily be done in the expr. But now I may start to sound like an
>>        obssessed DC Offset maniac.
>>
>>        Cheers
>>        Alex
>>
>>
>>        On Mon, Mar 30, 2009 at 1:25 PM, Claude Heiland-Allen
>>        <claudiusmaximus at goto10.org <mailto:claudiusmaximus at goto10.org>
>>        <mailto:claudiusmaximus at goto10.org
>>        <mailto:claudiusmaximus at goto10.org>>> wrote:
>>
>>           Alexandre Porres wrote:
>>
>>               On Mon, Mar 30, 2009 at 12:02 PM, Claude Heiland-Allen <
>>               claudiusmaximus at goto10.org
>>        <mailto:claudiusmaximus at goto10.org>
>>        <mailto:claudiusmaximus at goto10.org
>>
>>        <mailto:claudiusmaximus at goto10.org>>>
>>
>>               wrote:
>>
>>
>>                   [phasor~]                               [r~ shape]
>>                   [expr~ if($v1<$v2,$v1/$v2,(1-$v1)/(1-$v2))]
>>
>>
>>               I tried that, but it didnt actually worked, I just get
>> actual
>>               sawtooths, and
>>               no real triangles.
>>
>>
>>           Sorry for the shortness/lack of explanation, 0<shape<1, where
>>        1 for
>>           phasor, 0.5 for triangle, 0 for backwards phasor.
>>
>>           considering shape as a constant, obviously you get weird
>>        results if
>>           you modulate it, but that's half the fun:
>>
>>           0.0   <= input <= shape  ~>  0.0 <= output <= 1.0  (rising ramp)
>>           shape <= input <= 1.0    ~>  1.0 >= output >= 0.0  (falling
>> ramp)
>>
>>           Hope this helps,
>>
>>
>>
>>           Claude
>>           --    http://claudiusmaximus.goto10.org
>>
>>
>>
>>
>>        --        Alexandre Torres Porres
>>        cel. (11)8179-6226
>>        Website: http://porres.googlepages.com/home
>>        http://www.myspace.com/alexandretorresporres
>>
>>
>>    --    ::: derek holzer ::: http://blog.myspace.com/macumbista :::
>>    http://www.vimeo.com/macumbista :::
>>    ---Oblique Strategy # 35:
>>    "Consider transitions"
>>
>>
>>
>>
>> --
>> Alexandre Torres Porres
>> cel. (11)8179-6226
>> Website: http://porres.googlepages.com/home
>> http://www.myspace.com/alexandretorresporres
>>
>>
> --
> ::: derek holzer ::: http://blog.myspace.com/macumbista :::
> http://www.vimeo.com/macumbista :::
> ---Oblique Strategy # 87:
> "Imagine the music as a moving chain or caterpillar"
>



-- 
Alexandre Torres Porres
cel. (11)8179-6226
Website: http://porres.googlepages.com/home
http://www.myspace.com/alexandretorresporres
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