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• Learn the basics of the diminished 7th chord.
• Create a series of related chords based off the diminished chord shape.
• Understand the elements of proper voice leading.
I tend to be a bit obsessive when working on a technique or concept and recently diminished harmony has been filling my time. After a bit of consideration I realized that when the root of a diminished chord is raised by a half step an entirely new chord is formed. My next thought was that the diminished chord is symmetrical so each note in the chord can be moved up by a half step to form a new chord. I was pleased my theory proved correct!
Let’s begin with Cycle 1 and start with a basic voicing for Cdim7. In this example we will consider the C as the root of the chord. With each chord, we will move the root up a half step. If we move the C to a Db, we end up with Ebm7b5/Db. This is also known as an Eb half-diminished chord in third inversion. We now move the newly established root (Eb) up a half step to E and we create an F#m7/C# chord. Finally, we move the F# up to G and end up with an A7/C# chord. Once we move the A up to Bb, we begin the entire cycle again starting with C#dim7.
I found that each cycle revealed four chords (diminished 7th, half-diminished 7th, minor 7th, dominant 7th). In considering each diminished chord tone a potential root and series, we now have a total of sixteen chords! Each root will continue to ascend until arriving at a new diminished chord a half step above the original chord.
My last step was to consider the diminished chord as root position with three inversions. In other words, I didn’t move the chord or change the order of the notes. I looked at each note on each string as my new root. In Cycle 2 I use Gb as the root, Cycle 3, I use A, and in Cycle 4, I use Eb.
Identifying the chord quality and inversion will be the biggest challenge. It helps to remember that the order of the chord (diminished 7th, half-diminished 7th, minor 7th, dominant 7th). It also helps to understand the order of the inversions. Being based on open voiced chords, the order is root position, third inversion, second inversion, and first inversion. The order starts at different points considering which inversion you start with. For example, R–3–2–1 can also be 3–2–1–R, 2–1–R–3 or 1–R–3–2. Another way to look at it is that the root of each new chord moves in minor thirds.You can start ascending root movement from any of the four chord qualities but I consider diminished the parent chord.
You may say, this is interesting but why do I need to work on this? This study shows the close relationship between various chords and it helps with mapping intervals, chord spellings, as well as ear training. It’s also another approach to learning chord inversions. Anything that challenges your knowledge of the fingerboard and harmony is a good thing. This study can make your brain hurt, it did mine! In time, the concept will become simple. The video should clarify any questions you may have. In closing, it is my opinion that mastering the fingerboard and the harmonic universe would take many life times. We have one, better get busy!