BazzLow
ENIT
Module 13 · Lesson 4

Modes and chords

Match each diatonic seventh chord with its mode, and know when the choice matters for the bass.

Before this lesson: 13.3 Relative and parallel modes · 10.3 Diatonic seventh chords

A mode is a scale; a chord is a few of its notes. Connecting the two tells you which scale to play over each chord.

Each chord has a mode

Each diatonic seventh chord (lesson 10.3) is the 1-3-5-7 of the mode built on the same degree:

Each diatonic seventh chord and the mode on the same degree.
ChordIn CMode
Imaj7Cmaj7Ionian
ii7Dm7Dorian
iii7Em7Phrygian
IVmaj7Fmaj7Lydian
V7G7Mixolydian
vi7Am7Aeolian
viiø7Bø7Locrian

So a mode is a chord’s tones (1 3 5 7) plus the notes in between (2 4 6, or their alterations). The chord tones are the same for several modes. Three minor modes all fit a m7 chord: only 2, 4 and 6 tell them apart. These notes are the colour notes (or tension notes), and the scale that fits a chord is its chord scale.

RootThirdFifthSeventh2nd, 4th, 6th
Bass neck, frets 0–12Dm7 and its Dorian colour notes: the chord tones D F A C are in color; the colour notes E (2), G (4) and B (6) are grey. D at fret 5 on the A string, then E and F and G on the D string, A B C on the G string, and D at fret 7.GDA12345678DEFGABCD
Dm7 and its Dorian colour notes: the chord tones D F A C are in color; the colour notes E (2), G (4) and B (6) are grey. D at fret 5 on the A string, then E and F and G on the D string, A B C on the G string, and D at fret 7.

Choosing the mode

  • In a key, use the mode of that degree: Dm7 as ii in C → Dorian; Am7 as vi → Aeolian.
  • Over a dominant 7th chord, Mixolydian is the default, because it has the chord’s ♭7.
  • If the melody or harmony makes a 2, 4 or 6 audible, the bass must agree with it.

For a bass line built from chord tones and pentatonic notes, the choice often makes no difference: the minor pentatonic (1 ♭3 4 5 ♭7) fits Dorian, Aeolian and Phrygian alike. It matters when the line uses the 2nd or the 6th.

Try it

Over a held Dm7 (or a D drone), play D Dorian, then D Aeolian. Only B against B♭ changes. Decide which one fits a C major context, where B is natural.

New terms

Tools

  • Bass Map: Arpeggios, circle of fifths, natural harmonics, modes and scales on the bass neck, in any key.