User Guide

Chapter 4: Programming Basics 47
PROGRAMMING BASICS
This is the essence of the Z-plane filter. Through the use of
interpolation, many complex parameters are condensed down into
one manageable entity.
Consider, as an example, the human vocal tract, which is a type of
complex filter or resonator. There are dozens of different muscles
controlling the shape of the vocal tract. When speaking, however, we
don't think of the muscles, we just remember how it feels to form the
vowels. A vowel is really a configuration of many muscles, but we
consider it a single object. In changing from one vowel to another, we
don't need to consider the frequencies of the resonant peaks! You
remember the shape of your mouth for each sound and interpolate
between them.
Filter morphing can be controlled by an envelope generator, an LFO,
modulation wheels or pedals, keyboard velocity, key pressure, etc. The
filter Fc parameter controls morphing on certain Orbit filters. The Q
parameter on the Orbit filters can only be changed at note-on time but
can control various parameters such as boost/cut and mouth cavity
size and of course, resonance or Q.