We’re setting this all up to extrapolate a bunch of new chords and to add depth & meaning (what chords mean to chords) to our harmonic catalog. Following A Harmonic minor 7ths, we will use chords in this key to understand 2ndary Dominants (in C) and to create all Dominant chords from the fully diminished 7.
Harmonic minor differs from the Major scale by having a ♭3 & ♭6. It differs from Natural minor by having a normal 7. It differs from Melodic minor by having a ♭6.
We previously worked with the triads in this key. When we take the every other tone process until we have 4 tones in each chord (triads have 3), using the Harmonic minor tone set, in this case built on the tone A, we get the following qualities.
We can see the the half-step spacing between the components, and the distance to the 7th. For the diminished chord, the type of 7th is a ♭♭7 (aka, the 6).
These qualities are consistent across all of the Harmonic minor tonal centers.
For Root, 3rd, 5th, 7th, these are some type of each. Let’s look at the formulas (all compared to Major 7).
|minor Major 7||R ♭3 5 7|
|minor 7 flat 5||R ♭3 ♭5 ♭7|
|Aug Major 7||R 3 ♯5 7|
|minor 7||R ♭3 5 ♭7|
|Dominant 7||R 3 5 ♭7|
|Major 7||R 3 5 7|
|Fully diminished 7||R ♭3 ♭5 ♭♭7|
7 different chord qualities from one tone set is exquisite.