Basic Fun Equations - Kurzweil K2661 Musician's Manual

FUNS
The FUN Equations
value of +.5. An input value of -1 gives an output value of 0, as do input values of 0 and +1. An
input value of +.5 gives an output value of -.5.

Basic FUN Equations

The first six equations are weighted sums and differences—that is, the signal values of Inputs a
and b are added to or subtracted from each other, and are divided in turn by various amounts to
alter their effects relative to each other. These equations give you several different types of
mixers for combining the signals of the two inputs.
a + b
The values of Inputs a and b are added, creating a simple mixer. For example, you might have
LFO1 assigned for the Src2 parameter on a layer's PITCH page, and a FUN assigned for the
DptCtl parameter. On the FUN page, if you set Input a to a value of MWheel, and Input b to a
value of MPress, then this equation will let you modulate the depth of the LFO's pitch
modulation with your MIDI controller's Mod Wheel or with mono pressure. You could set a
fixed initial depth with the Mod Wheel and alter it further with mono pressure. In this case the
output signal would pin at +1 or -1 fairly quickly.
a - b
This operates similarly to the previous equation, but the value of Input b is subtracted from the
value of Input a. This equation will reverse the normal effect of the control source assigned to
Input b. For example, if Input a is off, and Input b is assigned to a unipolar control source like
MWheel, then the Mod Wheel will generate a control signal of -1 when fully down, and 0 when
fully up.
(a + b) / 2
The values of Inputs a and b are added, and the sum is divided by 2. This gives you the same
kind of control as the previous two equations, but the output signal will reach +1 or -1 half as
often as with the equation a + b.
a / 2 + b
The value of Input a is divided by 2, and the result is added to the value of Input b. Input a has
half the effect of Input b.
a / 4 + b / 2
The value of Input a is divided by 4, and the value of Input b is divided by 2. The two results are
added to give the output value. Input a has half the effect of Input b, and the total result has half
the effect of the previous equation.
(a + 2b) / 3
The value of Input b is multiplied by 2, and the result is added to the value of Input a. This sum
is then divided by 3. Input a has half the effect of Input b, and the total result has somewhat
more effect than the previous equation, but less effect than a + b.
a b
*
The values of Inputs a and b are multiplied. If you like using Src2 and DptCtl, this equation can
be used to create a similar type of control source (it's equivalent to the Src2/DptCtl pair with the
MinDpt parameter set to 0).
17-4