The seventh and extended chord types are the next level of harmony after triads. This post explores the structure of seventh chords, their construction and formulas. Additionally, this post will also reach into the expanded chord harmony theory of adding compound intervals by way of extended chords.
SEVENTH CHORD QUALITIES:
There are four primary seventh chords that exist within diatonic harmony. Plus, in the harmony of the harmonic minor scale, there are two other seventh quality chords that are known of as the Diminished 7th, as well as, the Minor /Major 7th.
The Four Primary Seventh Chords:
1). Major 7th = 1, 3, 5, 7
2). Minor 7th = 1, b3, 5, b7
3). Minor 7(b5) = 1, b3, b5, b7
4). Dominant 7 = 1, 3, 5, b7
Harmonic Minor’s Unique Seventh Chords:
The Harmonic Minor scale has two unique seventh chord types built upon this scales tonal center, (the I-chord), as well as, the leading tone (the scales VIIth degree).
1). Minor /Major 7th = 1, b3, 5, 7 (the I-chord)
2). Diminished 7th = 1, b3, b5, bb7 (the VII-chord)
EXTENDED CHORDS /COMPOUND INTERVALS:
Compound Intervals are used to extend chords beyond an octave. Extended Chords include chord types of: 9th, 11th and 13th types.
The Extended Chords we see most often are built on the chord qualities of; Major, Minor and Dominant chord types.
The most popular extended chords include:
Major, Minor and Dominant 9th
- Major 9th = 1, 3, 5, 7, 9
- Minor 9th = 1, b3, 5, b7, 9
- Dominant 9th = 1, 3, 5, b7, 9
Minor and Dominant 11th
- Minor 11th = 1, b3, 5, b7, 9, 11
- Dominant 11th = 1, 5, b7, 9, 11 (often called Dominant 9 sus)
Musicians tend to avoid the use of “Major 11” chords due to the semi-tone (minor 2nd dissonance) that is created from the presence of the Major 3rd interval clashing with the 11th (4th) interval. When an 11th is used within a Dominant chord, the 3rd is generally removed, thus creating a “suspended” (sus) chord.
Major, Minor and Dominant 13th
- Major 13th = 1, 3, 5, 7, 9, 13
- Minor 13th = 1, b3, 5, b7, 9, 11, 13
- Dominant 13th = 1, 3, 5, b7, 9, 13