FUNS
The FUN Equations
16-13
model we set up in the previous section, FUN1 was set to control Src1 on the PITCH page, and
Src1Õs depth was set to 1200 cents. With this equation, both input a (the Mod Wheel in this case)
and input b (the data slider in this case) would have to be more than halfway up for the FUN to
switch on. The pitch would jump 1200 cents as soon as both control sources moved above their
halfway points. As soon as one of them moved below its halfway point, the pitch would jump
back to its original level.
This equation can be used to trigger ASRs, or as a layer enable control, or for any control source
that toggles on and off. If you set one of the inputs to an LFO, the FUN would switch on and off
every time the LFOÕs signal went above +.5 (as long as the other input was also above +.5).
a OR b
This equation is very similar to a AND b. The only difference is that the FUN will switch on
when the value of either input a or input b moves above +.5.
Sawtooth LFOs
The next six equations case the FUN to generate a sawtooth LFO as its output signal. Each
performs a different operation on the values of inputs a and b, and the resulting value is
multiplied by 25. The result determines the frequency of the LFO. If the value is a positive
number, the LFO has a rising sawtooth shape. If the value is negative, the LFO has a falling
sawtooth shape. When the resulting values are large (above 10 or so), the output waveform is
not a pure sawtooth; a bit of distortion occurs.
ramp(f=a + b)
The values of inputs a and b are added, then multiplied by 25.
ramp(f=a - b)
The value of input b is subtracted from the value of input a, and the difference is multiplied by
25.
ramp(f=(a + b) / 4)
The values of inputs a and b are added, and the sum is divided by 4. This value is multiplied
by 25.
ramp(f=a
*
b)
The values of inputs a and b are multiplied, and the result is multiplied by 25.
ramp(f=-a
*
b)
The value of input a is multiplied by -1, then multiplied by the value of input b. The result is
multiplied by 25.
ramp(f=a
*
10^b),
10 is raised to the power of b, then multiplied by the value of input a. The result is multiplied
by 25.
Chaotic LFOs
The next Þve equations function somewhat like the equation a(b-y) described earlier, in that
they start with a value of 0 for y, evaluate the equation, and use the result as the new value of y
for the next evaluation. Although they all can function as LFOs (they can have a repeating cycle
of output values), they can become chaotic depending on the input values.
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