Chord Construction Using Modes

Chord construction using modes. The first mode of any major scale is called the Ionian mode; “do re mi fa so la ti do”. We know the intervals for that! They go “whole step, whole step, half step, whole step, whole step, half step to the octave”.

You can play C Ionian wherever you like, ascending and descending; the chart below shows it in the first position.

From left to right, here are the notes in sequence, right from one through seven and one as the octave. Ascending and descending, those guys have a solid, dependable interval relationship! That means between 1 and 2 is always going to be a whole step, between 2 and 3 is always going to be a whole step, between 3 and 4 is always going to be a whole step, all the way up to the half-step interval between 7 and 1… but only for one particular mode of the scale, which is the Ionian mode.

Other modes are different in that the intervals between the notes are shifted. However, the note sequence doesn’t change, we just start at a different point. So let’s take a look at the Dorian or second mode.

It’s the second mode so we start with the second note of the sequence. Since the Dorian mode starts with the second note and it’s an octave, it’s going to end on the second note too. The numbers will go:  2, 3, 4, 5, 6, 7, 1, 2. You can do that easily in the first position on guitar if you have the C major scale in the first position under your hand. “Under your hand” btw, is just a way of saying how well you know something you want to play; Patrick Kerrson describes it as being able to play an exercise/song/riff/chord or whatever you desire, 10 times in a row without making any mistakes. 

What we might notice when playing the scale from the second note is that the “character” of the scale has changed. It sounds quite different!

The character (or nature) of the scale that you just played changed from the character of the first scale because the third note is now a flatted third. You played D, E, F and even though F is not flattened per se, there is only a half step between the second note, in this case E, and the third note, which is the F. It’s only one and a half steps between the first note that you play and the third note that you play, and that means it has to be a minor!

Let’s look at the sequence of intervals again.

Start playing C scale notes at D and then go all the way up to D again, saying the intervals that you’re playing. Saying the note names out loud will be helpful too.

D to E is a whole step. E to F is a half step. F to G is a whole step. G to A is a whole step. A to B is a whole step. And then B the C is a half step and C to D is a whole step.

To my mind, this is pretty much a rule for Western music right here! Think about that octave. It  started on the D and ended on the D. If our first note was D, right, what was our seventh note? C, right?  So if the seventh note is a C and the octave is a D, what is the distance between those two? Of course it’s a whole step. 

Now here’s the magic:  we can apply the intervals from any mode- in this case, the dorian or 2nd mode- to the notes of the major scale!

Typically when we’re talking about the Ionian mode (do re mi), the distance between seven and one at the octave is a half step. But in the dorian mode the seventh note is another half step below that- So what kind of seven is that? It’s a dominant seven. 

So we know a few things: Since the third note is F and E to F is a half-step, instead of two whole steps to the third note, we have one and a half steps- so that means, this will be a minor chord! Since the 7th is a whole step to the C, it’s going to be a dominant seventh chord. We know what kind of third it has (minor) and we know what kind of seventh it has (dominant), and that tells us what kind of chord would be perfect to play C Dorian over: Cm7. 

“C minor seventh” is how we say that. When we refer to “a 7th”, we mean a dominant 7th, which is a whole step below the octave. “Minor” of course, refers to the character of the chord, defined by the flatted 3rd.

Using the C Dorian scale ( C = 1, D = 2/9, Eb = 3, F = 4/11, G=5, A=6, Bb=7) the chords we might play are Cm7, Cm7(9), Cm7(11), Cm6(9) Cm7(9,11). They’re all commonly Cm (root , flatted third and fifth) chords and the extensions are just built on the scale notes, as determined by the mode intervals. 

One additional thing that might be helpful: understanding the scale notes in a single position anywhere except the 1st position will make it easier to play these arpeggiated chords, as the fingerings are challenging!