[sdiy] FM with two oscillators

[Andre Majorel]

On 2001-10-31 20:01 +0000, Christian wrote:
> Hi everyone
> 
> A bit of a newbie question this -
>  
> I want to build my synth with two oscillators so VCO2 will modulate
> VCO1. I need this as I really love the rich Electric Guitar type
> sounds you can get - One of my favourites is 'Clarion Call'.
> I was wondering if it would be simply a question of feeding a
> proportion of the output of VCO2 back into the CV input of VCO1, or
> would there be other steps necessary.
> 
> Also, is FM only possible (or is it best) with sine waves - My VCO's
> currently only output Square with PCM, saw and triangle.
> BTW both the VCO's I have built have SYNC inputs.

FM is perfectly possible with a non-sinusoidal modulator. If
fact, that's the most common case. For instance, in a DX7, most
of the algorithms involve structures like

    OPx -> OPy -> OPz

In this case, the modulator of OPy is obviously not a sine.

-- 
André Majorel <amajorel at teaser.fr>
http://www.teaser.fr/~amajorel/