[sdiy] Modulation waveforms

[Scott Gravenhorst]

Tom Wiltshire <tom at electricdruid.net> wrote:
>Hi All,
>
>I've spent a lot of time the last couple of years developing 
>uP-based modulation sources of one type or another. I thought 
>some of you might be interested to see the results of my work in 
>this direction. My personal preference is for the random 
>waveforms, and I especially like the fact that they have an 
>underlying frequency, despite being random in some sense. This 
>lets you set up slowly varying sounds that don't just go 
>"woowoowoowoowoo". 
>
>http://www.electricdruid.com/AdvancedModulationGenerator.pdf
>
>Any comments appreciated.

Yes, random waveforms!  I too have in some of my designs a "random LFO"
which is really noise (from a 64 bit LFSR) through a lowpass filter,
usually just a simple single pole IIR, but I've also used a state
variable (2 pole) filter with resonance control for a more defined
frequency with randomness.  I far prefer these to the woowoowoo kind of
modulation acheived with non-random waveforms.  It sounds, for lack of a
better term, more natural.


-- ScottG
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-- Scott Gravenhorst
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