Module 2 · Lesson 2 of 4

Seventh chords and the colour they add

Major 7, dominant 7, minor 7 and half-diminished — the four you will actually use.

Building chords · 10 min read

Add one more third on top of a triad and you get a seventh chord. The four you need are: major seventh (1–3–5–7), warm and floating; dominant seventh (1–3–5–b7), restless and bluesy; minor seventh (1–b3–5–b7), smooth and neutral; and half-diminished (1–b3–b5–b7), tense and cinematic.

The dominant seventh is the engine of Western harmony. The interval between its third and its flat seventh is a tritone, and a tritone genuinely wants to resolve — outward or inward by a semitone into the notes of the home chord. That is why G7 pulls so hard toward C.

Sevenths are also the fastest way to change a genre without changing a progression. Play the same four chords as triads and it sounds like folk. Play them as sevenths and it sounds like soul. Nothing changed except one added note per chord.

Key points
  • Major 7 floats, dominant 7 pulls, minor 7 smooths, half-diminished aches.
  • The tritone inside a dominant 7 is what creates the pull home.
  • Adding sevenths is a genre switch, not a rewrite.
Practise this

Take a four-chord loop you already play and add the correct seventh to each chord. Record both versions on your phone and compare.

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