ChordMeloMelody Generator
Chapter 28About 2 minAll chapters

sus4, add9 and 6th — the practical colours

sus4 replaces the third; add9 and 6th add a note on top. One note is the difference between plain and current.

Modern pop accompaniment is rarely plain triads; a little colour has been added. Three additions cover most of it, and each is a one-note move.

Chapter 10 covered sevenths. In actual programming, these three turn up just as often. All of them are one-note operations on a triad.

sus4 moves the third out of the way

Chapter seven established that the middle note — the third — decides bright or dark. sus4 replaces that third with a fourth. With the deciding note gone, the chord is neither bright nor dark; it hangs.

  • CC (third present — bright)
  • Csus4Csus4 (third → fourth — hanging)
  • Csus2Csus2 (third → second — floating)
The middle note gets replaced. With no third, brightness cannot be judged.Buttons and keys in the diagrams play sound. Check your volume first.

Because it hangs, returning to the plain chord resolves it. Csus4 → C is the standard move, common at intros and at the door into a chorus.

In plain wordsSuspended chord (sus)

The third replaced by a fourth (sus4) or a second (sus2). With brightness undecided, it wants to move to the next chord.

add9 and 6th add rather than replace

These keep the third and stack a note on top. add9 adds the ninth — the second, an octave up — and 6 adds the sixth. Brightness survives; the sound just widens.

  • CC (triad)
  • Cadd9Cadd9 (shimmering)
  • C6C6 (soft, slightly old-fashioned)
The third stays; one note goes on top. Brightness is untouched, width increases.Buttons and keys in the diagrams play sound. Check your volume first.

That shimmer you hear in acoustic-guitar songwriting is usually add9. The 6th shows up in older popular songs and as a final chord in jazz. Both are lighter than sevenths and stay out of the melody's way.

Mixed into a progression

  • Plain triads (C, G, Am, F)

    C | G | Am | F

  • With colour (Cadd9, Gsus4, Am7, Fadd9)

    Cadd9 | Gsus4 | Am7 | Fadd9

The same I-V-vi-IV. The lower one adds one note per chord; the chords themselves are unchanged.Buttons and keys in the diagrams play sound. Check your volume first.

The second sounds more current, and the progression was not touched — one note per chord was. When a standard progression feels dated, this is the quickest place to work.

Generate over the coloured progression. More available notes means the melody's mood shifts too.

Generate over Cadd9, Gsus4, Am7, Fadd9
The one thing to remember

sus4 removes the third and leaves things hanging. add9 and 6th keep the third and add width.

Quick review

Everything here is answerable from this chapter. Pick an option and the answer appears straight away.

  1. Question 1

    What does sus4 do to a triad?

  2. Question 2

    What characterises add9?