About Funs - Kurzweil Forte Manual

Program Edit Mode
The Amplitude Envelope (AMPENV) Page

About FUNs

FUN is short for function. The Forte's four FUNs greatly extend the flexibility of the control
sources. Each FUN accepts input from any two control sources, performs a selectable
function on the two input signals, and sends the result as its output, which can be assigned
like any other control source. Using the FUNs involves defining them on the FUN page,
then assigning one or more of them as control sources.
There are three parameters for each FUN. Inputs a and b can be any control source from the
Control Source list. The control sources you want to combine are the ones you'll assign as the
values for these parameters.
The Function parameter determines what mathematical function is applied to the two
inputs. When a FUN has been assigned as a control source, the Forte reads the values of the
two control sources defined as Inputs a and b. It then processes them according to the setting
for the Function parameter, and the resulting value is the FUN's output.
All inputs to FUNs are scaled to a value in the range 0 to +1 or -1 to +1. A unipolar input
has a value between 0 and +1. A bipolar signal has a value between -1 and +1. For a unipolar
switch type input, OFF equals 0, and ON equals +1. For a bipolar input, -ON equals -1, and
ON equals +1. The 0-127 range of MIDI controllers gets scaled into these ranges. Unipolar
inputs to FUNs include MIDI switches and continuous controllers (sliders, wheels, etc).
Some continuous controllers can be bipolar as well. For example, the control source list has 2
choices for Mod Wheel: Mod Wheel (unipolar) and Bi-Mwl (bipolar). Envelopes and LFOs
can be unipolar or bipolar depending on their settings.
The output of FUNs can act as unipolar or bipolar control sources; it depends on the values
of the input signals and the nature of the function you choose. When the output of a FUN
is used as a Mod control source, the -1 to +1 range of values is scaled based on the Depth
setting of the Mod source. See the K2600 Musician's Guide at kurzweil.com for more details
and a description of each available FUN.
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