Tip for reharmonizing

Claim:

Within each of these three groups the chords are interchangeable:

Group 1: C7b9, Eb7b9, F#7b9, A7b9, Edim, Gdim, Bbdim, C#dim

Group 2: Db7b9, E7b9, G7b9, Bb7b9, Fdim, G#dim, Bdim, Ddim

Group 3: D7b9, F7b9, Ab7b9, B7b9, F#dim, Adim, Cdim, Ebdim

Proof:

(Without restrictions only for group 1)

C7b9: C E G Bb Db

Eb7b9: Eb G Bb Db E

F#7b9: F# A# C# E G

A7b9: A C# E G A#

Edim: E G Bb Db

Gdim: G Bb Db E

Bbdim: Bb Db E G

C#dim: C# E G A#

The diminished chords are all made up of the same notes. The dominant seventh chords with the flat nine have common tones with the diminished chords, only the root differs. When replaced, the different root can be viewed as an altered tone that increases tension. With a dominant seventh chord, this tension is desired and is usually subsequently resolved by a major or minor chord.

Remarks:

The idea for this comes from the course “Jazz Theory Unlocked” on jazzadvice(dot)com. I think the knowledge is older. I have formulated them in detail here in mathematical style.

All chords above can be used as dominant chords. You can leave out the b9. C7, Eb7, Gb7 and A7 are also interchangeable.

If you have a dominant, such as G7, you only need to go one semitone step higher for G#dim.

The interchangeable chords can be found by working in minor thirds (3 semitone steps).

These substitutions can be made in the major-ii-V-I progression.

In the minor ii-V-i progression, the V is often altered and b9 is an alteration. So this tip is good for that too.

I think this insight is useful when comping, composing and soloing.

 

Shuteen Erdenebaatar

I want to recommend the album “Rising Sun” by the Shuteen Erdenebaatar Quartet. She comes from Mongolia and studied jazz piano and jazz composition in Munich/Germany. I think she is as talented as Joey Alexander. The album contains many hymns to life. My favorite track is the melancholic piano solo piece “Summer Haze.”

Jazz Theory

I would like to recommend two courses to you because I believe that as a musician your life will be easier if you have studied the basics of music theory. Do you want to know what tones make up the chords and scales? What chord progressions are common in jazz?

There is the “Zero to Improv” course on learnjazzstandards(dot)com, which is a great way to get started. The “Jazz Theory Unlocked” course on jazzadvice(dot)com helped me understand the elements of a jazz composition. The chapter on the use of diminished chords was also enlightening.

These two courses helped me further.