Ab Chord Progressions: IV and iv Substitutions

Remember from last time:

I. Ab major
ii. Bbm
iii. Cm
IV. Db major
V. Eb major
vi. Fm
vii(b5). Gdim

Remember that the Ab major diatonic scale is as follows: Ab Bb C Db Eb F G Ab

Remember that the relative minor of Ab major (the chord and the scale) is F minor.

The F natural minor scale is as follows: F G Ab Bb C Db Eb F (compare with Ab major).

The F harmonic minor scale is as follows: F G Ab Bb C Db E F (note the singular difference between the natural and harmonic minor scales).

Now we have those ground rules established, it might help in the songwriting process to punctuate the IV chord with a iv chord, which makes things a bit Beatlesque (for lack of a better word). Going back to the simple relative minor substitutions from last time, let's try the following progression:

I-V-IV-IV: Ab Eb Db Db

Let's replace the V chord with its relative minor, the iii chord.

I-iii-IV-IV: Ab Cm Db Db

Let's try the III chord instead.

I-III-IV-IV: Ab C Db Db

Let's replace the second IV chord with a iv chord (which is a minor chord).

I-III-IV-iv: Ab C Db Dbm

Anyway, to connect with the natural minor and harmonic minor scales mentioned above, let's look at the IV and iv chords.

IV. Db major chord (Db F Ab notes)

iv. Db minor chord (Db E Ab notes)

Experiment with different chord progressions, and the best of luck to you in the songwriting process.