The Cyndustries List

Hi John,

You are laboring under a misconception (which can be painful).  There
is no such thing as a "base" frequency in the ZO.  The freq of the
oscillator follows this relationship:

  F = K * LinCV * 2^ExpCV

where:
F = oscillator frequency
K = a constant
LinCV = sum of all linear control voltages
ExpCV = sum of all exponential control voltages

It is now obvious that every 1V increase of ExpCV bumps one octave and
every _doubling_ of LinCV bumps one octave.  This equation also
reveals the need for linear bias because if LinCV = 0, the oscillator
stops.  You can also see that F becomes negative for negative LinCV.

To sum it all up (no pun), LinCV does not have a constant shifting
effect.  The amount LinCV will move F is dependent on ExpCV.  Also,
because the relationship is multiplicative and not additive, we do not
need to scale our LinCVs with frequency to achieve constant timbre up
and down the keyboard as classical FM would dictate.

I hope this clears this up for all.  If not, ask again and I'll try
again.  Cynthia, John and I want you to get the most out of your
Zeroscillators and the best way to do that is to be armed with
money...uh ah I mean knowledge.  Yeah that's it, knowledge.

--Mark Barton



--- In The_Cyndustries_List@yahoogroups.com, "john mahoney"
<jmahoney@...> wrote:
>
> > > is it possible to achive linear detuning with at least a pair of
ZOs?
> > > I.e. the set beating between the two ZOs stays at the same rate
while
> > > playing up and down the keyboard.
> 
> > The Zeroscillator is controlled both linearly and exponentially.
> > Because you use exponential control to play up and down the keyboard,
> > ratios between frequencies remain constant and not offsets.  This
> > results in the transposition of beat frequencies between oscillators
> > in the way you are familiar.
> 
> Can't you run the keyboard pitch CV into the expo inputs (for normal
pitch
> tracking) and a detune/offset CV into one osc's linear FM input (for
> beating)? Oh, wait... does a linear FM CV produce different frequency
> offsets at different oscillator frequencies? Okay, it's example time:
> 
> Say the osc is running at 1000Hz and we feed a certain CV (level =
X) into
> the linear FM input to yield an output frequency of 1004Hz. If the osc's
> base frequency is 2000Hz, will that same linear FM CV (level = X)
produce
> 2004Hx? Or something different, like 2002 (half) or maybe something
> unpredictable (2002.735Hz or something)?
> --
> john
>