How to Harmonize a Single Note With All Possible Chords

To harmonize a single note such as G, ask which chords contain it: three triads in each of the seven major keys that include G, six chromatic major and minor triads, and then chords on every one of the 12 roots, where G becomes a seventh, sixth, fourth, second, ninth or altered tone.

Video lesson by Jason Zac · Intermediate · 26 min

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In this music theory and songwriting lesson, Jason Zac takes one note, G, and works out every chord that can sit underneath it. If a melody leans on G, or a song lands on G, you can choose from far more chords than the obvious ones. The lesson suits intermediate players and songwriters who know basic triads and intervals and want fresh harmony. The same method works for any note.

Step 1: Diatonic chords from major scales

Start by asking which major scale you are in. G can be the 1st, 2nd, 3rd, 4th, 5th, 6th or 7th note of a scale, so seven major scales contain it: G, F, Eb, D, C, Bb and Ab major. In each of those scales, exactly three triads contain G.

• G major: G major, E minor, C major
• Eb major: Eb major, G minor, C minor
• C major: C major, G major, E minor

In some keys one of the three is a diminished triad, such as C# diminished (C# E G) in D major or E diminished (E G Bb) in F major.

A useful piano exercise: keep G as the top note and invert each chord so G stays on top, for example Eb major, C minor and G minor all voiced with G at the top. It doubles as an inversion workout.

Step 2: The six chromatic triads

Leave the single key and ask which major and minor triads anywhere contain G. There are always three major and three minor, and intervals help you remember them:

• G is the root: G major and G minor
• G is the perfect fifth: C major and C minor
• G is the major third: Eb major
• G is the minor third: E minor

To use this, let your melody wander, give G some emphasis by holding it longer, then land back on G with a different chord each time, such as C minor, Eb major or E minor.

Step 3: Anything goes, every root

Every one of the 12 roots has a chord containing G. Extensions of the chords above still work: Gmaj7, Gm(maj7), Gm7, G7; Cmaj7, C7, Cm7; Ebmaj7, Eb7; Em7, Em9. Then work down through the intervals, asking what G could be:

• Major seventh of Ab: Abmaj7 (Ab C Eb G), Ab minor-major seventh, Abmaj9.
• Minor seventh of A: A7, Am7 and Am7b5 (A C Eb G).
• Major sixth of Bb: Bb6 and the lovely Bb minor sixth (Bb Db F G). Treated as a diminished seventh, G belongs to Bb, C#, E and G diminished seventh, which are all inversions of one another.
• Augmented fifth or minor sixth of B: B augmented, B augmented major seventh and B7#5 (strictly G is spelled F double sharp here). B minor with an added G gives an eerie, sci-fi sound.
• Tritone of C#: C# diminished, or C#maj7 with the fifth lowered a semitone, a major seven flat five chord. Heard as a sharp four, it has a Lydian colour.
• Perfect fourth of D: Dsus4 (D G A) or D7sus4 (D G A C).
• Major second or ninth of F: Fsus2, Fadd2, F minor add9, and F9 with G on top of an F dominant seventh, plus minor and major ninths.
• Flat two or flat nine of F#: a Phrygian chord of root, b2, perfect fourth and fifth (F# G B C#), or F#7b9 (F# A# C# E G).

How to practise

1. Pick one note and list its three diatonic triads in a few keys.
2. Play the six chromatic triads with that note on top.
3. Go round all 12 roots, naming the interval the note forms with each root.
4. Improvise a melody that keeps returning to the note, changing the chord every time.
5. Repeat the whole process with a new target note.

Questions about this lesson

How many triads contain a given note?

Six major and minor triads contain any note. For G they are G major, G minor, C major, C minor, Eb major and E minor.

Which chords in a major key harmonize a melody note?

In any major scale that contains the note, three triads include it. In G major, the note G is found in G major, E minor and C major.

Can every root note harmonize the same melody note?

Yes. With extended and altered chords, G fits over all 12 roots, for example as the major seventh of Abmaj7, the sixth of Bbm6, the fourth of Dsus4 or the flat nine of F#7b9.

Why do four diminished seventh chords contain the same note?

A diminished seventh chord is a stack of minor thirds, so its inversions are themselves diminished seventh chords. Bb, C#, E and G diminished seventh share the same notes and all contain G.

Practise it

• Chord TreesStart from a note and explore related chords, inversions and voicings.
• Master KeyExplore diminished-seventh harmony, its resolutions and sixth-diminished sounds.
• All free music apps40 practice tools for harmony, rhythm, ear training and more.

Related lessons

• Truly Understand Modes From 2 Easy PerspectivesYou can understand modes in two ways: treat each mode as its own scale built from one root by changing intervals, or keep one key signature, such as F major with Bb, and start on each scale degree to get Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian and Locrian.
• How to Use the Circle of Fifths for Pro Chord WritingTo write non-diatonic progressions with the circle of fifths, move between neighbouring major chords such as C, F, Bb and Eb, or C, G and D, because each neighbour shares a common note and the change sounds smooth even outside one key.
• Ear Training: The Sounds of Intervals (How to Identify Them Fast)To identify an interval by ear, ask whether it sounds resolved (perfect fifth, major third, minor third), dissonant (minor second, diminished fifth, major seventh) or like it wants to move somewhere (major second, perfect fourth, minor seventh), with the sixths sounding mysterious and versatile.
• How to Sing and Play Intervals (Theory and Ear Training on Piano)To practise intervals in three dimensions, play a root note on the piano, sing the target interval first, then play it to check your answer, working from stable resolutions to anticipations and finally tensions.