Functional Harmony is simply creating a chord from every note in the key. For instance, you have C major. C-D-E-F-G-A-B.
C Major - C-E-G
D minor - D-A-F
E minor - E-G-B
F Major - F-A-C
G Major - G-B-D
A minor - A-C-E
B diminished - B-D-F
The point is to be able to hear this automatically. This awareness will help you discern which chord qualities are appropriate when building off of bass notes that may or may not belong to the key you're writing in.
Use the tab below to work out D minor harmony as well.