This module produces polyphonic pitch control voltage signals via S-Poly connections that represent the commonest three note chords.
The left/red outputs produce the voltages required for diatonic triads in a major scale.
The right/blue outputs produce the voltages required for diatonic triads in a minor scale.
The white labels next to each output indicate the chord type using Roman Numerals notation. These are independent of the key used. On the other hand the yellow labels change to indicate the chord’s name in the current key.
The KEY IN socket is used to control which key the chords are in. If no voltage is connected then the key defaults to C.
The KEY IN signal is a standard 1 V/Octave pitch signal. It is used to transpose the chords by simple addition so will handle octave offsets and non-standard tuning, but it’s also used to update the helpful yellow chord name labels. So the module is expecting the KEY IN voltage to be relatively stable. From an efficiency point of view it’s therefore best if things like vibrato or glides are added after this module .
Diatonic triads are three note chords that use only notes in a scale.
The notes within the chord are the root, third and fifth.
The most basic chords are I, IV and V. These are the standard chords used in the simplest three chord song.
If you look closely you will see that there are two blue graphical bridges from the minor outputs to the major outputs. These are visual hints that V is often used instead of v and vii dim and VII are often interchanged too.
The Diatonic Triads module is introduced in LSSP 101 Tutorial 3.