The theory behind modal chord scales
In the modes series, we identified 7 modes
. Each mode was built on a degree/note of its parent scale - e.g. mode 2
Dorian was built on the 2nd
degree of the major scale. Mode 5
Mixolydian was built on the 5th
We also learned each mode as major, minor or diminished (7th mode Locrian - the "odd one out").The same applies when building chords on the degrees of the major scale.
Below is a diagram showing the intervals of the major scale. Each yellow box can be seen as a degree of the major scale, so each one also represents a mode, from 1 (Ionian) to 7 (Locrian) and then back to 1 again.
The numerals correspond to the mode number 1-7. You can also see that the maj/min
label corresponds with that mode's flavour. For example, 3rd mode Phrygian is a minor mode, so therefore the 3 (iii) chord will also be minor. 4th mode Lydian is a major mode, so therefore the 4 (IV) chord will also be... yep, major! It's just like superimposing chords onto the mode patterns, using some or all of the mode's tones in the chord.
By knowing the interval sequence between each mode (covered in the "big picture" lesson of the series), we automatically know the interval sequence of the modal chord scale
So, based on this knowledge, if we were to assign the root chord of the sequence - I
- as E major
, the sequence would progress as follows...
In modal terms, that's E Ionian
, F# Dorian
, Ab Phrygian
, A Lydian
, B Mixolydian
, C# Aeolian
, Eb Locrian
and then the octave E Ionian (from which the sequence repeats).
Remember, this is a movable relationship, so if the I chord
(also called the "tonic") changed to D major
, the same interval sequence would be built accordingly. This is why it's important to know the the fretboard!
Once we're confident with building these interval sequences in any key
(the key being defined by the tonic I
note/chord), we can then move on to learning how to identify modal chord sequences - applying the correct mode to chord combinations from this scale.Common modal chord progressions
For these examples, we'll use the C major
chord scale, which means the Ionian/I chord will be C major. But remember, the sequences we build are relative
to wherever that tonic Ionian/I chord lies.
So, from that C major chord scale, we can assign a tonic chord to each of its degrees, to build progressions around its associated modes. To make it a modal progression, it must resolve to a tonic chord within that scale
. Let's look at some examples:Ionian chord progression
Dorian chord progression
|Progression:||C (I) Dm (ii) G (V)|
Phrygian chord progression
|Progression:||Dm (ii) Em (iii) Dm (ii) G (V)|
Lydian chord progression
|Progression:||Em (iii) F (IV) Em (iii) Dm (ii)|
Mixolydian chord progression
|Progression:||F (IV) G (V)|
Aeolian chord progression
|Progression:||G (V) Dm (ii) G (V) F (IV)|
|Progression:||A (vi) F (IV) G (V) A (vi) Dm (ii) Em (iii)|
Locrian has been left out simply because Locrian's associated chord - the diminished (m7b5) chord - isn't really appliable as a tonic
chord. In other words, it doesn't provide a resolution to a progression because it naturally sounds unresolved!
Locrian, therefore, is used as more of a modal link/bridge between two other chords in the scale (mainly, the vi minor and I major tonics).
So, hopefully from listening to those examples above, you can hear a different tonic/resolution chord in each modal progression we use. It's this stable tonic chord that brings out the mode's unique flavour.
In a nutshell...
- Each mode has its own tonic chord.
- Chord progressions can be built around each mode to highlight their tonic. The tonic therefore also defines the key of the progression.
- The chord progressions are built using related chords from other modes in the same modal scale.