More ramblings about VCDO...

[Tim Ressel]

mb,

Your point is well taken. Digital oscillators are ruined by the same thing that
makes them great: their ultimate stability. The idea of "ruining" the
oscillators by injecting filtered noise into the CV inputs is certainly one way
to make VCDOs more natural sounding. However I am uncomfortable with expending
effort to produce the perfect oscillator and then spending more effort to make
it more like an analog VCO. Instead I will leave my VCDO as is, and create a
separate module that produces filtered noise for the oscillator banks. 

Another possibility is this: Since I need a processor on the front end to
perform A/D conversions on the incoming CV and convert it to numbers the VCDO
can swallow, that same processor can create filtered noise to inject onto the CV
stream.

Tim Ressel -- Hardware DQ
Hewlett-Packard
Verifone Division
916-630-2541
tim_r1 at verifone.com



> ----------
> From: 	mbartkow at ET.PUT.Poznan.PL[SMTP:mbartkow at ET.PUT.Poznan.PL]
> Sent: 	Thursday, July 08, 1999 9:00 AM
> To: 	synth-diy at mailhost.bpa.nl; Tim_R1 at verifone.com
> Subject: 	RE: More ramblings about VCDO...
> 
> Now the trick I learned from Analogue Heaven (there is some interesting stuff
> posted from time to time, BTW): get a white noise source and bandpass filter
> it
> about 30Hz. Use this filtered noise to slightly detune each DCO group. Mind
> you,
> each grup has to be detuned differently, so you need few different noise 
> sources. A pair of evenly tuned DCOs sounds extremely fat and analoguish
> when slightly modulated by two noise signals.
>