I was talking to a musician friend of mine over the weekend and we somehow got into the area of chord substitution and I thought that today would be a good day to delve into that a little bit.
In the interest of ease of communication, I am going to use the numerical names of the chords instead of the letters for this first part, that way you can apply it to any key readily. Using the key of C as the chord paradigm, the numerical i.d. works like this:
C = I
Dmin = ii
Emin = iii
F = IV
G = V
Amin = vi
Bmin = vii
The major chords are identified with large roman numerals and the minor chords are identified with lower case roman numerals.
Now in any chord progression that goes I, IV, V, interesting tonal color changes occur when you begin to replace, say the IV, with the ii. The ii is known as the “relative minor” of the IV, because it is using many of the same notes that exist in the IV. That’s why it is easy to use it in place of the IV. It changes the tonality, but only slightly.
I wasn’t going to get into this, but just so you understand, a basic triad C chord has the notes C – E – G in it. Two notes below the C in the key of C is the A, and by starting the chord on the A instead of the C the triad becomes A – C – E or Amin. That’s why it’s called the relative minor. It has two notes of the major chord of that particular key in it. This works in any key, obviously. Try finding the relative minor of G, A, F, D. It will be intuitively obvious to you after a moment how this works. Now back to a little substitution.
Try playing the I, IV, V chords in the key of C. That would be C, F and G chords. Now try replacing the IV or F with the ii or Dm. Do you hear the slight change in the mood of the chord? To me, it is somehow a little more plaintive, more sad then the F.
In western music, the minor chords traditionally are associated with sadness, so this would make sense. Even if the key remains a major key, the addition of the minor adds some pathos to the progression.
Now if you go through the progression like this, I, IV, V two times and then replace the IV with the ii the next two times you play it, you will hear a difference between the two progressions. If after that you replace the I with a vi, (C with Amin) you will hear the whole tonality change, because for a moment you will be in the minor as opposed to the major mode, Amin being the relative minor of C, as you will recall.
Now take a simple song that you know and play it. Because we’re using I, IV, and V, lets use the song “Louie, Louie”. Every garage band probably played this song for a moment. The song was in Animal House as well, so I am pretty certain this is a familiar enough song. Okay, play the chorus a couple of times and then replace the IV chord with the ii chord. The song still works, but it is slightly different, right?
Now keep playing the song, but replace the I with the vi. Do you hear how the song has changed? Same melody, same tempo, but now it is a different thing altogether.
This is the most basic example of chord substitution. Wednesday, we will talk about some more sophisticated applications.