[sdiy] Imperfect VCO

[Czech Martin]

?
The wave is then a point symmetrical 256 samples wave, that should give
about 128 independent partials (oh well, always the question with
the one at 0 and pi/2 ;->).

This symmetry is no limitation in terms of partial amplitude, but only in phase.

Of course this give a harmonic wave without any animation.
Just like a good VCO without too much phase noise or other
artefacts.

m.c.

-----Original Message-----
From: ASSI [mailto:Stromeko at compuserve.de]
Sent: Freitag, 1. August 2003 22:31
To: synth diy
Subject: Re: [sdiy] Imperfect VCO


On Friday 01 August 2003 12:36, Czech Martin wrote:
> I used a Waldorf Microwave I together with some Atari program
> that allows for wave drawing (almost) in real time.
> This means a wave has 128 (or was it 256?) samples of 8 bit

128 samples, but only the first half of the wave is stored and the rest 
is mirrored for the other half of the cycle, so that the wave is always 
symmetric and DC free. This gives you 64 harmonics to play with.

> The outcome was that little nonidealities of the wave form
> were not audible. Perhaps a slight difference in a A/B
> comparison.

One thing to note is that no matter what you do, the harmonics of the 
resulting (unprocessed and non-aliased) wave will be at integer 
multiples of the fundamental. This property gives the "single wave" 
sound a very distinctive "digital" quality (you get the same from a 
K5000, btw). To get things going you really must modulate through an 
appropriately constructed wavetable, perhaps conciding with some mild 
FM to break up the partials and give them some movement.


Achim.
-- +<[ Q+ & Matrix-12 & WAVE#46 & microQkb Omega sonic heaven ]>+ --

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