[sdiy] 60s organ sound

[Antti Pitkämäki]

Glen wrote:

>I checked the waveforms coming out of my Vox SuperContinental, and there
>are a fairly wide variety of shapes generated for the various individual
>notes. Some low notes look like a cross between a saw and a square wave
>(basically a square wave where the trailing edge droops down dramatically
>toward zero), but with rounded corners. Some notes look basically like a
>square wave, sometimes with rounded corners, and sometimes not so rounded.
>Some notes look like a sine wave. The mixtures are complex and defy easy
>description. There's a fairly wide variety.

Well there must be filtering, but what about the pure unfiltered waveforms 
that are generated by the dividers? Note that the "mixture" drawbar is a 
mixture of 4 different pitches, but I guess you knew that already.

>If someone tries to use a saw wave from a synth to mimic the Vox, they will
>be missing the mark. There's too much variety here. To simply substitute a
>saw wave (or any other single waveform) for everything and expect it to
>sound like a Vox.

It might be about the filtering... Quickly thinking, 7 sawtooth waves at the 
same pitches as what the Vox produces, should have at least a similar sound, 
but not necessarily exactly the same. Low pass filttering without any 
keyboard tracking and maybe with some resonance might make the sound more 
"coloured", and less "pure". Of course the Vox must be more complex than 
that.

In my original lost mesage I wrote about synthesising combo organ sounds... 
Let's try again:
Anyways, here is an idea what to try to make a simple Farfisa/Vox-kinda 
sound: take three oscillators producing sawtooths, set them so that the 
second oscillator is an octave higher than the first, and the third osc is 
an octave higher than the second, and hard sync them... Of course this sound 
would be quite clean, it might benefit from some "colouring" from filtering, 
overdrive etc. (note: this would not sound like those Vox sounds that use 
the mixture drawbar, since it produces 4 additional picthes (2 of them are 
dissonant)) Changing the waveforms and intervals of the oscillators would 
produce differnet sounds. Try square waves for all oscillators: that's the 
cheesy organ sound!

Antti Pitkämäki

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