About Triad Pairs

A triad pair is a combination of two triads that can be played over a chord to create a particular harmonic sound. The two triads do not necessarily belong to the underlying chord. Their relationship to the chord is what creates the color.

The examples below are all shown in the key of C. Once you understand the relationship between the chord and the two triads, the same ideas can be transposed to any key.

1. Major 7 Chords

   Triad pairs on major 7 chords are useful for creating both straightforward major sounds and brighter Lydian colors.

   1. Major

      Cmaj7 → G major + A minor

      The notes are (5 • 7 • 2) and (6 • 1 • 3), giving you the 1, 2, 3, 5, 6 and 7 of C major. This creates a straightforward major sound without emphasizing the 4th.

   2. Lydian

      Cmaj7#11 → D major + E minor

      The notes are (2 • #4 • 6) and (3 • 5 • 7). Together they create the characteristic #4 of the C Lydian sound while retaining the major 3rd, 5th, 7th, 9th and 13th.

2. Dominant 7 Chords

   Dominant chords offer some of the richest applications for triad pairs. Different pairs can produce inside dominant, suspended, Lydian dominant, altered and whole-tone sounds.

   1. Mixolydian

      C7 → G minor + A minor

      The notes are (5 • b7 • 2) and (6 • 1 • 3). Together they outline the basic C Mixolydian sound without using the 4th.

   2. Suspended Dominant

      C7sus4 → F major + G minor

      The F major triad supplies the 4th, 6th and root, while G minor supplies the 5th, b7th and 9th. This creates a suspended dominant sound without emphasizing the major 3rd.

   3. Suspended Dominant with b9

      C7sus4b9 → F major + G diminished

      The F major triad provides the suspended 4th and 6th. The G diminished triad adds the 5th, b7th and b9th. The result is a darker suspended dominant sound.

   4. Lydian Dominant

      C7#11 → E diminished + F# diminished

      The two diminished triads produce the 3rd, 5th, b7th, #11, 13th and root. This gives a strong Lydian dominant sound, particularly useful when a dominant chord has a #11 or when you want a brighter dominant color.

   5. Whole Tone

      C7#5 → C augmented + D augmented

      The two augmented triads produce the 1, 3, #5, 9, #11 and b7 of the dominant chord. Because augmented triads are symmetrical, this creates the characteristic floating sound of the whole-tone scale.

   6. Dominant 9 with #5

      C9#5 → G minor + A♭ augmented

      G minor supplies the 5th, b7th and 9th, while A♭ augmented supplies the #5, root and 3rd. This creates a strong altered dominant sound while retaining the familiar shape of two simple triads.

   7. Fully Altered Dominant

      C7alt → Db minor + Eb minor

      Db minor supplies the b9th, 3rd and b13th, while Eb minor supplies the #9, b5th and B7th. This creates a strong altered dominant sound by essentially removing the root from the standard altered scale.

3. Minor 7 Chords

   Minor 7 chords can support several different colors depending on their harmonic function. The examples below are particularly useful for minor chords functioning as ii chords or as modal minor chords.

   1. Dorian

      Cm7 → E♭ major + F major

      The E♭ major triad supplies the b3rd, 5th and b7th. F major supplies the 4th, 6th and root. Together they outline the essential notes of C Dorian.

   2. Dorian with an Open Sound

      Cm7 → F major + G minor

      F major gives the 4th, 6th and root, while G minor gives the 5th, b7th and 9th. The minor 3rd is left out, making the sound less explicitly minor and more open and modal.

   3. Minor 7 with Extensions

      Cm7 → D minor + E♭ major

      D minor supplies the 9th, 11th and 6th, while E♭ major supplies the b3rd, 5th and b7th. This is another way of organizing the Dorian sound around two familiar triads.

4. How to Think About Triad Pairs

   The most useful way to approach triad pairs is not to memorize a list of shapes. Instead, ask what each triad is doing against the underlying chord.

   1. Chord Tones

      Which notes of the triads provide the 3rd, 5th and 7th of the chord?

   2. Extensions

      Which notes provide the 9th, 11th or 13th?

   3. Alterations

      Which notes create tensions such as b9, #9, #11, b13 or #5?

   4. Harmonic Color

      What does the combination sound like against the chord? A pair might create a major, Lydian, Dorian, Mixolydian, altered or whole-tone sound.

   5. Resolution

      How does the sound want to resolve when the underlying chord changes? This is particularly important when using triad pairs over dominant chords.