[PD] pd book sprint

[Alexandre Porres]

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> 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>> 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>>
>>        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
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