[PD] pd book sprint

[Hans-Christoph Steiner]

On Mar 31, 2009, at 4:34 AM, Frank Barknecht wrote:

> Hallo,
> Alexandre Porres hat gesagt: // 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.
>
> And a [triangle~] may be used as a ping-pong looping [phasor~].
>
> The objects Pd provides are building blocks - they generally are  
> designed on a
> level that allows and encourages multiple uses. A square wave going  
> from 0 to 1
> can be used as a logical signal that switches another signal on and  
> off. In
> fact, a trivial square or saw without bandlimit should generally not  
> be used as
> an "oscillator" in the analog synth sense - it should be bandlimited  
> first, and
> while you do that you may as well make them have a DC of 0.   
> (Bandlimiting
> triangle waves is not *that* urgent, as corners don't add so many  
> alias
> components.)

I think the key to this discussion of -1 to 1 vs 0 to 1 is what people  
are most likely going to use them for, and what makes the most sense  
in that context.  Of course, ideally, it wouldn't create arbitrary  
restrictions either.  For example, Cyrille and I make basically  
everything 0 to 1 in the mapping library since it makes things really  
easy to do without sacrificing much flexibility.  If you start with,  
or end up with different ranges, you can do the scaling math at the  
input or output ends of the patch, and keep everything in between 0 to  
1.

I think the two ranges for this discussion separate signals versus  
controls.  A sawtooth~ is a signal that is meant to be listened to, so  
it would good from -1 to 1.  A phasor~ is the exact same shape as a  
sawtooth~, but it is meant to be a control, so it is 0 to 1.  You  
could easily switch the two with some basic math, but most of the  
time, you'll want your controls to be 0 to 1 and your signals -1 to  
1.   A similar pair would be square~ (signal) and pwm~ (control).

.hc


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