[sdiy] Modulation question

[Luís Marka]

In some cases cross-modulation is a good idea. At times I can use a low 
frequency VCO or a CV-controlled LFO modulated by an envelope, or by 
another LFO. Also it is nice to have some sort of synchronization: a LFO 
that resets the wave at "x" BPM, for example, or when a Sync signal is 
received. Envelopes are naturally synced by the trig input anyway.
Also, recyclable envelope generators (where the trig happens again 
automatically at the end of the Release cycle) dubbing as periodic 
sources are welcome too.
Maybe I am missing something, but what you described is much similar to 
a S&H-type modulator with some waveshaping at the output. By the way, I 
also use a S&H with LFOs or envelopes at the "sample" input, not only 
white noise (in my modular the internal noise source is bypassed by 
plugging a jack at Signal input, and the Rate has CV In *and* can also 
be bypassed). I don't have an envelope follower module (yet!) but this 
could add some more options.

Think this pretty much should cover most of your bases in the modulation 
department!

Cheers,
Luis Marka


Tom Wiltshire wrote:
> Hi All,
>
> I've been thinking about modulation sources on synths. Basically you 
> get envelope generators of some sort, and LFOs.
>
> One of these generates aperiodic changes, and the other produces 
> periodic changes. I had thought that that pretty much covers it, since 
> every kind of change is either periodic or aperiodic.
>
> However, there is something else which I'd been missing which is that 
> some changes are predictable and some are not. Envelope generators are 
> a source of predicable aperiodic changes, and LFOs are obviously 
> predictable, since they're periodic.
>
> Consequently, I'm currently working on an unpredictable aperiodic 
> modulation source, done digitally. The basis is a 64-bit LFSR noise 
> source. The source (I'm calling it a random modulation generator, RMG) 
> can either interpolate linearly between noise values to produce random 
> slopes, or interpolate quadratically to produce random curves. I've 
> been having an absolute bitch getting sufficient accuracy out of 
> 16-bits to allow really slow modulation waves.
>
> That's the background, but what I'd like to know is whether there are 
> other important types of modulation that I'm still missing.
>
> What's your favourite modulation?!
>
>
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