Von: Tkacs, Ken <
ken.tkacs@...>
> In terms of audio signals, Z-plane filters, etc., the term "morphing" does
> have some merit, but those are more complex, multi-dimensional signals,
not
> simple summations.
There's nothing than weighted summations in a digital filter (;->), but
I know that was not your point.
You are completely right:
> A control voltage is just a level at a particular point
> in time, so it seems strange to refer to a varying CV as 'morphing.' Is an
> EG "morphing" it's output? I guess technically, "morph" just means "form,"
> so one could argue that it does, but it seems odd to apply that term to
such
> a simple process. The whole point of voltage-controlled synthesis is the
> ability to alter voltages in real time, so by that definition, they're
∗all∗
> morphing.
... but there is more:
You build two different sounds (two patches) in a modular. Now you can
use a dual VCA to crossfade between the two signals. That's crossfading,
not morphing.
You can use one synth engine with everything under voltage control,
and then you can switch between sets of CVs. That's what every synth
with patch storage does. Switching, not morphing.
And finally you can do a crossfade for each and every CV, rather than
simple switching. That means a dual VCA for ∗each∗ parameter. I think
there is good reason to call this "morphing".
The difference to crossfading can be a dramatic one, depending on
the way you create the morphing. There is more than one way to do it.
Well, sometimes there is just one obvious way: If Sound #2 has
a different decay time on the filter than Sound #1, you will obviously
change the CV for the Decay Time.
But if Sound #2 has a different VCO waveform and / or pitch, you have
some choices: Gliding the pitch up or down is one option, but surely
not to most unobstrusive one. Alternatively, you can use hard sync
and interpolate the pitch CV, or use two locked (hard sync'ed) VCOs
with different pitch and do a crossfade between the two VCO outputs.
Whatever fits your needs for ∗your∗ idea of morphing on that particular
sound.
So I need a dual VCA for each parameter ?! (JH. will be glad, because
his royalties will shoot up (;->) )
It's not that bad. You only need VCAs for parameters that are different
for both patches. The good news is that you can do some stunning
morphing with a rather limited number of parameters. My old
morphing programmer has 6 channels (not all are VCA-based, but that's
a different story), and I rarely used them all. More like 4 or 5, normally.
Of course you can do a lot of other weird stuff with all these CV inputs.
You're perfectly right: That's what a modular system is all about.
This morphing stuff is just a subset of the "total freedom": The special
charm of morphing is that you can change a set of several CVs with
∗one∗ CV in a predefined (pre-patched) way.
It's important that this is possible independently of any time constants.
It's not just "start with sound 1, fade to sound 2" - that would be boring.
You can use a controller (pedal, aftertouch, you name it) and morph
halfway from 1 to 2, then back to 1, then fully to 2, all in realtime.
It's like creating a "Macro" of parameters which resonds to your input
in a way you defined it.
I hope this shed some light rather than adding to the confusion,
JH.