II-V-I mineur dans une suite d'accords

Music Lesson: Minor Cadence and Chord Sequences

Introduction

In this lesson, we'll explore a minor cadence, specifically the A minor 2-5-1 sequence, within a cycle of chords that incorporates all seven chords and modes of the major scale.

Chord Sequence

The chord sequence will follow this order:

2, 5, 1, 4, 7, 3, 6

By familiarizing yourself with these Roman numerals, you should be able to voice a chord and find its corresponding mode on each degree of the scale.

Modes and Chords

1. Chord II: Dorian mode (Minor 7 chord)
2. Chord V: Mixolydian mode (7th type chord)
3. Chord I: Ionian mode (Major scale)
4. Chord IV: Lydian mode
5. Chord VII: Locrian mode
6. Chord III: Phrygian mode
7. Chord VI: Aeolian mode

Playing the Cycle

Listen to this cycle of chords. I will start by playing the root notes, followed by the chord tones for each chord.

• 1, 2, 1, 2, 3

Key Modulation

While I described the last chord (E minor) as chord vi, it may be more helpful to think of it as chord I of the relative minor key.

Thus, instead of viewing our seven chords as a cycle strictly related to G major, we can interpret the second half as a 2-5-1 progression into E minor.

While we're still diatonic, we haven't added any notes outside of the G major/E minor key signature. This perspective allows for a flexible progression between the two keys.

Enhancing the Modulation

To make this modulation more effective, I will transform my III chord into a seventh type chord. Specifically, I want my F# minor 7 flat 5 (Locrian) and B chord to form an A II V into E minor.

If the B chord is now the V, I need it to be a seventh type chord. I'm going to make a subtle change by altering the minor seventh chord into a seventh chord.

Changing the Chord

I will raise the third of the B minor chord to a D sharp. This will create a leading tone, which provides a strong pull into E minor.

• B minor 7 chord sounds like this on the piano...
• After raising the third to D sharp, it will sound like this...

By adding that one note outside of our diatonic seven modes, the leading note from the harmonic minor scale, we enhance the sound quality, allowing for a smooth transition into E minor.

Final Sound

Over the track, our chord tones with the added seventh chord will now sound like:

2, 1, 2, 3, 4

I've emphasized the D sharp to highlight its role as the note outside our previously learned modes. Integrating this leading note into your seventh chord will vividly illustrate the modulation between G major (the tonic key) and E minor (the relative minor).