Extended Chords: Different Types & How They're Formed 7,9,13
Extended chords are simply chords that have notes which extend further than the standard three note triad. They're formed by stacking thirds on top of the base triad.
Extended chords provide another layer of sound above general major and minor triads. They can add that extra spice that a song needs or can be that mystery chord that you can't quite figure out when learning a song by ear. The 'extended' portion of the chords are the extra thirds which are stacked above the base triad. Remeber, triads are formed by stacking the 1st, 3rd, and 5th degrees of the scale. Here are the types of extended chords I'll be cover in this tutorial:
7th Chords
To make a seventh chord you start with the base triad and add the 7th scale degree on top. Whether that added third is major or minor is dependent on the type of 7th chord. Here are the three types of 7th chords I'll be showing you:
- Major 7 (M7)
- Minor 7 (m7)
- Dominant 7 (7)
Major 7th Chords:
The major 7th chord is a major triad with a major third stacked on the top. The sound of the major 7 chord is open and airy, it's used very regularly in jazz.
C major 7 chord (CM7)
Notes: C - E - G - B
When do they work?
Major 7th chords occur diatonically as the IM7 & IVM7 in major keys and IIIM7 & VIM7 in minor keys.
Minor 7th Chords:
To construct a minor 7 chord take a minor triad and add another minor third on top.
C minor 7 chord (Cm7)
Notes: C - Eb - G - Bb
When do they work?
The minor 7 chord occurs diatonically as a iim7, iiim7, & vim7 in a major key and im7, ivm7, & vm7 in a minor key. Basically, any diatonic minor chord could also be played as a minor 7 chord and still sound right.
Dominant 7th Chords:
The dominant 7th chord is a major triad with a minor third stacked on top of it. It's natural tendency is to resolve a fourth down. It's used a lot in blues and jazz
C Dominant 7 Chord (C7)
When do they work?
Dominant 7th chords occur diatonically as a V7 in all major keys and can be played non-diatonically as a V7 in minor keys. Additionally, when playing a standard twelve bar blues progression it's quite common to use a dominant 7 for all chords in the progression.
The non-extended diatonic V triad is called the dominant chord, which is where the dominant 7th gets it's name.
9th Chords
Now it's time to get even more extended. Major and minor scales only have seven notes, so how do you build a chord using the ninth? As you may have guessed, the ninth scale degree is essentially the second scale degree but in the next octave up.
In most cases ninth chords include both the seventh and the ninth scale degrees; for this reason ninth chords have more variations. This is actually the case for most chords which have an interval greater than seventh. Here are the types of 9th chords I will be showing you:
- Add 9 (add9)
- Dominant 9 (9)
Add9 Chords
An Add9 chord is simply a triad with the 9th degree added in. Unlike the 9th chords described below, add9 chords typically don't include a 7th scale degree.
Cadd9 Chord
What's interesting about add9 chords is that they can be substituted for any diatonic triad in a major or minor key and still be diatonic (aka sound correct). If used with a major triad it adds some ethereal color to the chord. When used with a minor triad it adds a bit of dissonent tension.
Dominant 9 Chords
Dominant 9 chords (typically written as C9) are constructed by stacking the 9th scale degree on top of a dominant 7 chord.
C9 Chord
