[PD] slop~ (new object for 0.50) and the "slew" term

[Miller Puckette]

My guess s3is that the q105 is a true slew limiter but that whoever's selling it
on that page misunderstood what it does.  Here's one reliable source:

https://en.wikipedia.org/wiki/Slew_rate

(note "Musical Applications" section at bottom.)

cheers
Miller

On Tue, Jul 23, 2019 at 11:41:11AM -0300, Alexandre Torres Porres wrote:
> oh, found the module that led me to assume all that I had assumed :)
> 
> https://synthesizers.com/q105.html
> 
> Em seg, 22 de jul de 2019 ??s 23:39, Alexandre Torres Porres <
> porres at gmail.com> escreveu:
> 
> >
> > Hi, I'm having some fun with the new (and yet to come) slop~ object, which
> > should be in Pd Vanilla in the next release and is already included in the
> > source code.
> >
> > I'm going ahead and I'm also including it in my live electronics tutorial.
> > I already have examples on how to use it for a signal linear (with 3rd and
> > 5th inlet) and exponential (with 4rd and 6th inlet) portamento, see =>
> > https://github.com/porres/Live-Electronic-Music-Tutorial/blob/master/Tutorial/Vol.1/Part.01-Basic.Audio/04-Gain.Adjustment/5.Signal.smoothening.%5Bslop~%5D.pd
> >
> > I was also able to implement a cool non linear envelope with [vline~] +
> > [slop~]
> > https://github.com/porres/Live-Electronic-Music-Tutorial/blob/master/Tutorial/Vol.1/Part.03-Control/15-Envelopes/2.Classic.Types/6.%5Bvline~%5D.%5Bslop~%5D.pd
> >
> > Now for some questionings;
> >
> > So, [slop~] generates linear ramps and also, as a one pole filter, it
> > generates non linear ramps. Anyway, I've seen the term 'slew' being used in
> > synth modules as a portamento generator and then I was assuming, for some
> > reason, it should be like this one pole filter, so I have a [slew~] object
> > in the else library that does that kind of lowpass filtering (see:
> > https://github.com/porres/pd-else/blob/master/Classes/Source/slew~.c )
> >
> > slew~ takes an input in ms, which is the period of the portamento, and one
> > could also use something like [rpole~]  and convert the ms value to the
> > coefficient with the formula coef = exp(ln(0.001) / (ms/1000 * samplerate))
> > - and I got this formula from the documentation of some object I don't
> > remember from SuperCollider..
> >
> > Anyway, what I ask is if that object name makes sense. The [slop~] object
> > makes me think it's ok, but by looking at it, it seems that a so called
> > 'slew rate limiter' always seems to generate linear ramps, so maybe all so
> > called 'slew' modules only generate linear ramps and calling my object
> > "slew~" can be inappropriate.
> >
> > What do you say?
> >
> > thanks
> >

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