[sdiy] More Digital VCO samples available

[Paul Maddox]

Eric,

> The other thing I've noticed is that the aliasing really only sounds like 
> aliasing on frequency sweeps. When I use the DVCO with fixed frequencies 
> (like with MIDI notes) the aliasing doesn't seem to resolve into discrete 
> tones but rather just comes through as background fuzz.

yep, I've noticed that, I'm sure there's a 'name' for this effect :-)

> The square-wave aliasing can be significantly reduced by clipping the 
> filtered sine in the analog domain. That eliminates a lot of the edge 
> jitter because the gentler slope of the sine's zero crossing gives more 
> accurate timing. This suggests a use for the final op-amp stage that's 
> currently languishing in the corner with nothing to do. Possibly another 
> CV input for a comparison threshold and a clipped/PWM output?

yeah, why not :-)

> I'd never really played with syncing before this and it's interesting how 
> it sounds more like resonance and/or formants on the frequency that drives 
> the sync. This is really apparent on the sine sync.

You'll get a kick out of this ;-
http://www.clavia.se/nordmodular/Modularzone/VOSIM.html

http://www.modulus-music.com/sounds/VOSIM/vosim1.mp3 (1Mb)
http://www.modulus-music.com/sounds/VOSIM/vosim2.mp3 (441Kb)

these are a couple of MP3s from the configurations on the Clavia sight.
use of synced sines to get 'vocal' harmonics.
Ok, VOSIM, is a little different, but it's a good demonstration of sync'd 
sines.

this one, was from the wernerkaegi(the guy who 'created' VOSIM) site when it 
was still up
http://www.modulus-music.com/VOSIM/vosim3_dual_gen.wav (673Kb)

this *REALLY* shows the power of VOSIM (which I really must do some more 
work with at some point).

> Now that I've learned what it's like, I've been able to identify it in 
> some of the electronic music I listen to - Steve Roach seems to use it 
> often in some of his more ambient stuff.

Possibly, though it's more likely those come from something like the 'nose 
flute' sounds from the Big Korg keyboards.

Paul