10.36Build chords from formulas

Pick any root.

Say:

D♭maj7

Formula:

1 3 5 7

D♭ major scale:

D♭ E♭ F G♭ A♭ B♭ C

So:

D♭ F A♭ C

Now:

D♭7

lower 7:

D♭ F A♭ C♭

On the piano, C♭ sounds like B.

Notation may look strange, but the formula stays logical.