Located at the top of the AutoTheory GUI in between the Scale and Mapping, is the Global Chord Types parameter. This important control defines what type of chords will be output by the Chord Generator. It sets the values for the step octave parameters within the Chord Editor. While more experienced players will probably dive into the Chord Editor “step” functions, many users will be fine with just setting the Global Chord Types parameter.
The available options found within the Global Chord Types parameter provide users with different ways of grouping and organizing chords. In many situations musicians make use of inversions or voicings to play chords in creative and unique manners. Inversions and voicings are what we call it when we move certain tones found within a chord to the same note on a different octave. This changes the pitch of the chord, but does not affect the overall character of the chord. This is very helpful to understand and apply when you are also mixing, and need to have an idea about where different instruments fit into the mix frequency wise. With that being said, let’s take a look at some of the different options available to you within the Global Chord Types parameter.
Here is what each chord looks like when you use the GCT value of Sevenths with a Dorian Scale (i-ii-III-IV-v-vi*-VII). You can see that the root tone along with all other tones gets higher in pitch with each chord. If you are looking for a shift in pitch with each chord selection, this might be a good way for you to go.
Here is what each chord looks like when you use the GCT value of Seventh (inv) with the same Dorian Scale and chord ordering. You will see that the i chord has all of its tones in the same location. With the ii and III chords however, the last tone has been moved down in front of the root tone. With the IV and v chords, the last two tones have been moved down in front of the root tone. With vi* and VII, the last three tones have been moved down in front of the root tone. These inversions serve the purpose of keeping every tone of every chord within an octave. Although the pitch of the inverted chords has changed, the overall character of each chord remains the same.
Seventh (voiced 1.5):
Here is what each chord looks like when you use the GCT value of Seventh (voiced 1.5) with the same Dorian Scale and Chord ordering. You will see that most of the chords are spread out over a one and a half octave range. This provides each chord tone with a little bit more room to breathe. When using seventh chords, this is often effective as there is an added tone that can make things a little more cluttered. The octave adjustments performed to achieve these voicings are not quite as straight forward as traditional inversions.
Sevenths (voiced 2):
Here is what each chord looks like when you use the GCT value of Seventh (voiced 2) with the same Dorian Scale and Chord ordering. You will see that all of the chords are spread out over a two octave range. This provides each chord tone with a lot of room to breathe. As with the (voiced 1.5) value, the octave adjustments performed to achieve these voicings are not quite as straight forward as traditional inversions.
When you look at the outcomes of the Global Chord Types parameter, you can see that you are provided with different ways of approaching the frequency spectrum in the mix.
Do you want a chord progression that changes in frequency? Then you probably should not use any inversions or voicings.
Do you want a chord progression that fits snugly into a one octave range? Then you probably should use inversions.
Do you want a chord progression that maintains frequency and spreads out over multiple octaves? Then you probably should use one of the options for voicings.
With each option, there are potential conflicts that could arise as well. If you are using voicings that go into the frequency range (octave) of another instrument, it could potentially create problems in the mix where neither instrument is clearly defined. If you are trying to fit harmonically rich seventh chords into a lower one octave range however, that too could also give you some extra work in the mix. Consequently it is very important to have an overall awareness about what instruments you are using, and which octave (frequency range) they are occurring on.
The examples provided in this tutorial relate to seventh chords, but the principals are the exact same for triads and fifths.