Modes Explained 8: Modes and Progressions

Whilst a full discussion on chords and chord progressions is beyond the focus of a series on modes, a brief review is given here. However, if you are entirely unfamiliar with chord construction and chord progressions, I strongly recommend that you search the internet and explore this topic further before proceeding with the rest of this series.

Building Triads on Each Note of the Major Scale

Within the key of C major we have seven notes – C, D, E, F, G, A and B. We can take any one of these notes as a root note to build a chord on. For instance, building a triad on the note C gives us C, E, and G which is a Cmaj triad. Chords can be built from any note in the scale in the same way. Starting on the note E and including every second note from the scale would give us the notes E, G and B forming an Emin triad. Likewise, building a triad on the note G would give us a Gmaj chord with the notes G, B, and D.

We call the chord built on the first note of the scale the “Ⅰ” chord, the chord built on the second note of the scale the “Ⅱ” chord, and so on using Roman numerals to designate which degree of the scale the chord has been built upon. If the chord is a minor chord this can be indicated by using a lower case Roman numeral (eg ⅳ instead of Ⅳ) or can be indicated by adding a lowercase “m” after the Roman numeral (eg Ⅳm). In this post I use the more traditional convention of using lowercase Roman numerals for minor chords and uppercase Roman numerals for major chords.

The table below gives an example of all of the diatonic chords in the key of C major, each numbered with Roman numerals. The table also shows the corresponding mode beginning on each scale degree.

Roman Numeral	Chord Quality	Actual Chord in Key of C Major	Corresponding Mode in Key of C Major
Ⅰ	Major	C Major	C Major / C Ionian
ⅱ	Minor	D Minor	D Dorian
ⅲ	Minor	E Minor	E Phrygian
Ⅳ	Major	F Major	F Lydian
Ⅴ	Major	G Major	G Mixolydian
ⅵ	Minor	A Minor	A Aeolian
ⅶ	Diminished	B Diminished	B Locrian

Building Sevenths and Extended Chords on Each Note of the Major Scale

Of course, we’re not restricted to building only triads (three note chords) on each scale degree. We can build four note chords (usually seventh chords), or ninth, eleventh and thirteenth chords if we so chose. Here is the same table again, but this time indicating the types of chords available using seventh chords. Note how the Roman numerals stay the same, however the number seven is added to indicate that it is representing a seventh chord. Also, for the B half-diminished seventh chord, a circle with a line through it (ø) is the standard symbol indicating half-diminished.

Roman Numeral	Chord Quality	Actual Chord in Key of C Major	Corresponding Mode in Key of C Major
Ⅰ7	Major Seventh	C Maj7	C Major / C Ionian
ⅱ7	Minor Seventh	D Min7	D Dorian
ⅲ7	Minor Seventh	E Min7	E Phrygian
Ⅳ7	Major	F Maj7	F Lydian
Ⅴ7	Dominant Seventh	G7	G Mixolydian
ⅵ7	Minor	A Min7	A Aeolian
ⅶø7	Half-Diminished Seventh	B Minor	B Locrian

Chord/Scales

Back in part 6 of this series we learned about chord/scales. That post gave an introduction as to which mode suited which chord for the purposes of melodic construction, including improvisation. In that post I also provided a table showing which mode was appropriate for which chord. That table has been reproduced below for easy reference.

Chord Name	Applicable Mode(s)	Mode Formula	Avoid Notes
Major Triad	Lydian	1 2 3 #4 5 6 7
	Ionian	1 2 3 4 5 6 7	4
	Mixolydian	1 2 3 4 5 6 b7	4
Sus2 Triad	Lydian	1 2 3 #4 5 6 7
	Ionian	1 2 3 4 5 6 7
	Mixolydian	1 2 3 4 5 6 b7
Sus4 Triad	Ionian	1 2 3 4 5 6 7
	Mixolydian	1 2 3 4 5 6 b7
Minor Triad	Dorian	1 2 b3 4 5 6 b7
	Aeolian	1 2 b3 4 5 b6 b7	b6
	Phrygian	1 b2 b3 4 5 b6 b7	b6, b2
Maj7	Lydian	1 2 3 #4 5 6 7
	Ionian	1 2 3 4 5 6 7	4
Min7	Dorian	1 2 b3 4 5 b6 7
	Aeolian	1 2 b3 4 5 b6 7	b6
	Phrygian	1 b2 b3 4 5 b6 7	b6, b2
7	Mixolydian	1 2 3 4 5 6 b7	4
Half-Diminished (aka Min7b5)	Locrian	1 b2 b3 4 b5 b6 b7	b2

As we learned in part 6 and as you can see from the table above, Phrygian, Aeolian and Dorian all suit a min7 chord, however only the Dorian mode is ideally suited to min7 chords as both the Phrygian and Aeolian modes have avoid notes when used over min7 chords. However in this post, rather than looking simply at which scales suit which chords, we will investigate which scales suit which chord progressions. By looking at chords in a musical context (i.e. a progression), we actually find many circumstances where a Phrygian or Aeolian mode may be more suitable than the ordinary Dorian mode for minor seventh chords. Similarly, whilst the Lydian mode is considered to be the most consonant mode over major type chords, we will see that Ionian may often be a better choice in many situations.

The Ⅳ-Ⅴ-Ⅰ Progression

The Ⅳ-Ⅴ-Ⅰ progression is a hallmark of Western music. In the key of C a Ⅳ-Ⅴ-Ⅰ progression is Fmaj-Gmaj-Cmaj and using seventh chords the progression would be Fmaj7-G7-Cmaj7. As we know from part 6 of this series, the default mode for the major seventh type chord is the Lydian mode since, unlike the Ionian mode, Lydian has no avoid notes. Therefore, for Fmaj7 we would use the F Lydian mode.

For the G7 chord we can use the Mixolydian mode, although it is important to remember that the natural fourth (the note C) in the G Mixolydian mode is an avoid note. As we know we can raise avoid notes by a semitone to make them more consonant. Raising the avoid note of the Mixolydian mode gives us the Lydian Dominant scale which was introduced in the previous post.

For the final chord, Cmaj7, the Lydian mode seems like a logical choice due to its lack of avoid notes, however most players would probably choose the Ionian mode instead, despite the presence of an avoid note. Why is that? Well, this progression is in C major (we know this because the Ⅰ chord is a C major chord). C Lydian, while certainly a possible choice, is actually derived from the G major scale, which is a completly different key centre. Using the F# from a C Lydian may sound like a ‘wrong note’ or it may suggest to listeners that you are modulating to the key of G major. Of course, experienced players may deliberately choose C Lydian as the #4 could prove more interesting. Typically speaking though C Ionian is the safer choice as it belongs to the the key.

Similarly, regarding the G7 chord, G Mixolydian belongs to the key (G Mixolydian is derived from C major), and may therefore be a better choice than G Lydian Dominant which is derived from an entirely different tonality. G7 is therefore the safer choice, however the #4 in Lydian Dominant may also be suitable for more colour, depending on the situation and player.

The ⅱ-Ⅴ-Ⅰ Progression

Like the Ⅳ-Ⅴ-Ⅰ progression, the ⅱ-Ⅴ-Ⅰ progression is one of the most common chord progressions in Western music. In the key of C major a ⅱ-Ⅴ-Ⅰ progression is Dmin-G-C, or, using seventh chords, Dmin7-G7-Cmaj7. The final two chords in this progression are G7 and Cmaj7, which is the same as the last two chords in the Ⅳ-Ⅴ-Ⅰ. Our mode choices are therefore the same, with G7 suiting either a G Mixolydian or G Lydian Dominant, and Cmaj7 fitting well with C Ionian or C Lydian. Once again G Mixolydian and C Ionian are safer choices in terms of adherence to the prevailing key, while G Lydian Dominant and C Lydian, are suitable if you are after a fresher/hipper sound, or prefer their lack of avoid notes.

For the ⅱ chord, Dmin, the obvious choice is the D Dorian mode. Dorian is the default choice for minor seventh type chords as it has no avoid notes. Also, because the D Dorian mode is derived from the C major scale, it belongs to the prevailing key.

The Ⅰ-ⅵ-Ⅳ-Ⅴ-Ⅰ Progression

The Ⅰ-ⅵ-Ⅳ-Ⅴ-&#8544 is another hugely popular progression. In the key of C major this would be rendered as Cmaj-Amin-Fmaj-G7-Cmaj. As the first chord is a Ⅰ chord, we will be sticking with the mode built of the tonic – C Ionian. Also, the final three chords in this progression is the same as our Ⅳ-Ⅴ-Ⅰ progression above, so for those chords we will be using F Lydian, G Mixolydian and C Major respectively.

For the ⅵ, Amin, it would make sense to use either A Dorian, A Aeolian or A Phrygian as these are the main modes used for minor type chords. Since Dorian has no avoid notes, it would appear to be the obvious choice, however A Dorian is derived from the G major scale and will therefore contain an F#. F# is not a note that belongs in the key of C Major so it is very possible that choosing A Dorian may sound “off key”. A more reliable choice would be the A Aeolian mode as this mode is derived from the C Major scale and will therefore agree with the prevailing key which is C Major. Or course once again, choosing to use the A Dorian mode, with its non-diatonic F# is not necessarily “wrong”, just be aware that you may need to exercise more caution when using it.

Choosing Modes Based on the Prevailing Key

At this point it should be obvious that the main way to achieve a mode which complements and agrees with the progression is to choose a mode derived from the prevailing key. In effect, this means choosing the first mode of the key (Ionian) for the Ⅰ chord, the second mode of the key (Dorian) for the ⅱ chord, the fourth mode (Lydian) for the Ⅳ chord, the fifth mode (Mixolydian) for Ⅴ, and the sixth mode (Aeolian) for ⅵ. Accordingly the Phrygian mode would ideally suit the ⅲ chord, and Locrian will work well for the ⅶ.

Recognising Chord Progressions

Unless you are a session player, you’ll rarely encounter chord progressions written out as numbers or Roman numerals like I have done in this post. Usually chord charts are only written with their actual names, such as Cmaj, G6/9 etc. This means that, in order to use the information presented above, you’ll need to develop your familiarity with chord progressions and learn to recognise certain progressions when they appear. For instance Fmin-Bb7-Ebmaj immediately screams ⅱ-Ⅴ-Ⅰ in the key of Eb major.

The only way to really develop this automatic recognition is to analyse LOTS of charts until it becomes automatic. Of course, its important that you also have a good grounding in chord progression theory before you try this, so if you feel like your knowledge of progressions is lacking, then you’d better enter a few search terms in a search engine!

Minor Key Chord Progressions

So far we’ve only really touched on modes as they relate to chord progressions in major keys. Progressions in minor keys are slightly more complicated so for now it may be wise to limit your study of chord charts to songs in major keys. Minor key songs can become very complicated very quickly, so we’ll look at those specifically in the next post.