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The Soft Buttons in the Program Editor
The Program Editor's soft buttons are labeled by the words that appear in the bottom line of
the display. These buttons have two important jobs in the Program Editor: selecting pages, and
selecting specific functions. If a soft button is labeled in all uppercase letters, pressing it will
take you to the page it describes. If the button is labeled in mixed uppercase and lowercase
letters, pressing it will execute the software function described by the label. Pressing the PITCH
soft button, for example, will select the PITCH page, while pressing the Save soft button will
initiate the process for saving the currently selected program.
There are more pages and functions in the Program Editor than there are soft buttons.
Therefore, two of the soft buttons are dedicated to scrolling through the list of pages and
functions. If you don't see the button for the page or function you want to select, press one of
the soft buttons labeled <more>, and the labels will change. This doesn't change the currently
selected page, it merely changes the selection of available soft buttons.
Five of the soft buttons in the Program Editor are special cases. They're the soft buttons that
select the editing pages for the five control input pages for the DSP functions. One of these soft
buttons is always labeled "PITCH," since the first DSP function in every algorithm is the pitch
control. The remaining four vary somewhat depending on the DSP functions you choose for
the currently selected algorithm, but they always have the prefixes F1, F2, F3, and F4, and they
always take you to the pages for the four DSP functions that follow the pitch control function.
Algorithm Basics
The basic definition: an algorithm is the "wiring" (signal path) of a sample to the audio
outputs, through a series of digital signal processing (DSP) functions that you select. The
K2500's algorithms are the core of Variable Architecture Synthesis Technology. The DSP
functions are synthesis tools (filters, oscillators, etc.) that you assign to the various stages of the
algorithm. The DSP functions you choose determine the type of synthesis you use.
Each of the 31 available algorithms represents a preset signal path. You can't change the path of
the algorithms, but you can select different algorithms, and assign a wide variety of DSP
functions to the individual stages of each algorithm's signal path. Take a look at Algorithm 1 in
the diagram below. It's one of the simplest algorithms.
Algorithm|1||||||||||||||||||||||||||||||
|||||||||||||||||||||||||||||||||||||||||
errR®rrterrR®rrrrrrR®rrrrrrR®rrterrR®rrt|
dPITCH|gkHIFREQ|STIMULATOR|||||gkAMP|||gh
cvvvvvvbcvvvvvvvvvvvvvvvvvvvvvvbcvvvvvvb|
The DSP functions are represented by the rectangular blocks. The horizontal arrows indicate
the flow of the digital signal from left to right. They represent what we call the "wire" of the
algorithm, the actual physical path that the signal follows through the algorithm. Selecting
different algorithms can be compared to connecting different DSP functions with different
wiring diagrams.
Think of the left side of each block as its input, and the right side as its output. Depending on
the algorithm, the signal may split into two wires, enabling part of the signal to bypass certain
portions of the algorithm. Split wires may rejoin within the algorithm, or they may pass all the
way through as split signals. If the last block has two wires at its output, we call it a double-
output algorithm. If it has one wire, it's a single-output algorithm, even if there are two wires in
earlier portions of the algorithm.
The five downward-pointing arrows indicate the five realtime control inputs to the DSP
functions. There are usually five inputs, each of which has its own page within the Program
Program Mode and the Program Editor
Using the Program Editor
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