[PD] backwards ead~
Andy Farnell
padawan12 at obiwannabe.co.uk
Mon May 30 20:34:16 CEST 2011
You might be able to easily get that behaviour by
quickly editing the example I gave you.
The maths is really geometry.
There are a few things that can be done as time domain
transforms when thinking about envelopes and suchlike
in this way.
1) Flip it around zero with [*~ -1]
2) Invert arithmetically wrt 1.0 using [sig~ 1][-~]
3) Get the [min~] or the [max~] wrt another value
4) Clamp at a value using [clip~] ... is special case of (3)
5) Shift by an amount using [-~] or [+~]
6) Scale by some factor with [*~]
IIRC the idiom for a two stage envelope like that is
to use [min~]/[max~] to create a split point and treat
each of the two branches differently (you can do piecewise
waveform construction the same way).
If you want time symmetry then have the [vline~] go to 1.0
and back to [0.0] and just use one of the branches.
On Mon, 30 May 2011 18:45:55 +0200
Stephan Elliot Perez <dreamoftheshoreofanotherworld at gmail.com> wrote:
> Greetings,
> Thank you for your responses. I tried your suggestion, hardoff, and
> the result is the attached [ead-reverse~]. Unfortunately, the expression
> behaves differently with this [vline~]-construction as with the [phasor~].
> Here, if 1 is entered into the right input of [expr~], the result is an
> envelope whose steepness becomes exponentially smaller while ascending and
> exponentially greater while descending (if near 0, the opposite form is
> produced and values between 1 and 0 produce a divided, confused form). I
> however wish to produce an envelope that becomes exponentially steeper both
> ascending and descending.
> My problem with this [expr~] as well as with Mr. Farnell's patches is
> that I do not quite understand the math behind them. Any ideas?
>
> Best regards,
> Stephan Elliot Perez
>
>
> On Fri, May 27, 2011 at 5:54 PM, hard off <hard.off at gmail.com> wrote:
>
> > instead of the [phaser~], send a [line~] (or [vline~]) signal.
> >
> > for example:
> >
> > [1, 0.5 500, 0 1000 500(
> > |
> > [vline~]
> >
> >
> > like most of my patches, i don't think i originally made that one, someone
> > else posted it, and i just copied. ;)
> > must have been a long time ago though, cos i barely remember it.
> >
> >
> >
> >
> > On Sat, May 28, 2011 at 12:24 AM, Stephan Elliot Perez <
> > dreamoftheshoreofanotherworld at gmail.com> wrote:
> >
> >> Greetings,
> >> I wish to produce a wave form with the opposite form of the normal
> >> ead~ wave (the curves become exponentially steeper instead of flatter),
> >> which I can achieve by entering a negative number into the phasor in hard
> >> off's exact-ead~ patch, which I downloaded from the archive. However, I
> >> still want to be able to independently change the length of the ascent,
> >> decline, and distance between waves as is possible with ead~. Does anyone
> >> know how I could do this, or possibly have access to an abstraction-version
> >> of ead~?
> >>
> >> Best regards,
> >> Stephan
> >>
> >>
> >>
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> >
--
Andy Farnell <padawan12 at obiwannabe.co.uk>
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