Seventh chords

A seventh chord adds a fourth note above the triad. Depending on which seventh you add, you get a dreamy major 7, a bluesy dominant 7 or a mellow minor 7. Knowing the three formulas lets you build any of them.

By the end of this lesson you will be able to:

• State the formulas for maj7, dominant 7 and minor 7.
• Play the common open seventh chords.
• Use V7 to I as a resolving move.

A seventh chord adds a fourth note, the seventh, on top of a triad. There are three main types.

• Major 7th (maj7): 1 3 5 7. A major triad plus a major seventh, one semitone below the octave. Dreamy, relaxed. Cmaj7 = C E G B.
• Dominant 7th (7): 1 3 5 ♭7. A major triad plus a minor seventh, a whole tone below the octave. Bluesy, with tension that wants to resolve. C7 = C E G B♭.
• Minor 7th (m7): 1 ♭3 5 ♭7. A minor triad plus a minor seventh. Smooth, mellow. Cm7 = C E♭ G B♭.

In a major key, the seventh chords are: Imaj7, ii7, iii7, IVmaj7, V7, vi7 and viiø7. In C: Cmaj7, Dm7, Em7, Fmaj7, G7, Am7, Bm7♭5.

V7 to I is the strongest resolution in tonal music. G7 contains B and F, which are a tritone apart and want to resolve to C and E, so G7 pulls strongly to C.

A plain "7" in a chord name means dominant 7. A major seventh is written "maj7".

From triad to seventh.

1. Play C (x32010). Lift your first finger off the B string: the open B is the seventh. You are playing Cmaj7 (x32000).
2. Put C back and add your pinky on the G string at fret 3. The open G string becomes a B♭ in the chord, and the shape (x32310) is C7.
3. Play Am (x02210), then lift the third finger: the open G string is the seventh. You are playing Am7 (x02010).

V7 to I. Play G7 (320001), then C (x32010). The pull from G7 to C is immediate. Do the same with D7 to G and A7 to D.

Hear the colours. Each seventh chord has a different mood. Try to name them before you think about the notes.

Do these in order. Each one is small. Tick the ones you have practised.

• 1.Triad to seventh

  4 min

  1. Play C. Lift your first finger off the B string to play Cmaj7 (x32000).
  2. Put your pinky on the G string, fret 3 to play C7 (x32310) from C.
  3. Play Am, then lift the third finger to get Am7 (x02010).

  You have it when

  • You can move between C, Cmaj7 and C7, and from Am to Am7.
  I practised this one

• 2.Hear the three sevenths

  4 min

  1. Play C, Cmaj7 and C7 one after another. Describe each in a word.
  2. Play Am, then Am7. Note how the seventh softens it.
  3. Write your descriptions in your journal.

  You have it when

  • You can describe the sound of each type in your own words.
  I practised this one

• 3.V7 to I

  4 min · 60 → 90 BPM

  1. Play G7 then C. Notice how G7 seems to pull towards C.
  2. Do the same with D7 to G and A7 to D.
  3. Four beats each, repeat for two minutes.

  You have it when

  • You can hear the pull of V7 towards I.
  I practised this one

Start at 60 BPM with four beats per chord. The goal is accuracy and ear, not speed.

• Confusing maj7 and dominant 7. Maj7 uses the major seventh (a semitone below the root, 1 3 5 7). Dominant 7 uses the flat seventh (a tone below, 1 3 5 ♭7).
• Playing sevenths as decoration without hearing them. Compare the triad with the seventh chord, so you hear what the extra note adds.
• Assuming every 7 means a major 7. The plain symbol C7 means dominant 7. Major 7 is written Cmaj7.

The 12-bar blues uses dominant sevenths on every chord (A7, D7, E7). Maj7 and m7 chords turn up in ballads and folk, where they add colour to a simple progression.

Try it in: 12-bar blues in A.

Short version (10 minutes)

Play C, Cmaj7 and C7 in turn for two minutes, listening to each.

Standard version (about 30 minutes)

Do all three exercises, then play the first four bars of the 12-bar blues in A.

• Maj7: 1 3 5 7. Dominant 7: 1 3 5 ♭7. Minor 7: 1 ♭3 5 ♭7.
• Dominant 7 chords pull towards I (V7 to I).
• Maj7 sounds dreamy; m7 sounds smooth.
• A plain '7' in a chord name means dominant 7.

You are ready to move on when you can honestly say:

• I can state the formulas for maj7, dominant 7 and minor 7.
• I can play at least five open seventh chords.
• I can hear a V7 resolve to I.