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Chartwell/Books/Music/Theory/Augmented Chords.txt
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Augmented Triads
An augmented triad is a 3-note chord built by stacking two major 3rds. The term “augmented” comes into play because the interval from the root of the chord to the 5th is an augmented 5th. Another helpful approach for constructing an augmented triad is to begin with a major triad and then raise the 5th by a ½ step. (Think: Root, 3rd, #5).
Major 7(#5) Chords
Major 7(#5) Chords combine an augmented triad with a major 7th (Think: Root, 3rd, #5, 7). Building this chord on the note C, we get CEG#B. Common chord symbols for this chord include Cmaj7#5, C#+, and Cmaj7(#5). You may even see this chord written as a slash chord, E/C.
Dominant 7(#5) Chords
Dominant 7(#5) Chords combine an augmented triad with a minor 7th (Think: Root, 3rd, #5, b7). Building this chord on the note C, we get CEG#Bb. Common chord symbols for this chord are C7#5 and C7(#5). This chord is often associated with the Whole Tone Scale, particularly when the #9 is included, as in C9(#5).
Where do augmented chords come from?
Augmented chords are unique because they do not occur naturally within the major scale. Rather, the augmented triad is a diatonic chord in both the Harmonic Minor Scale and the ascending Melodic Minor Scale. In both scales, the augmented triad occurs as the 3-chord (III+) due to the raised 7th scale degree.
Augmented Triads and Harmonic Function
Although the augmented triad appears in minor scales, it rarely functions as a III+ chord in minor keys. More often, it appears as I+, III+, or V+ in major keys. The augmented 5th interval typically acts as a passing tone in chromatic voice leading over a major triad.
Augmented Triads in Scales
The Whole Tone Scale produces augmented triads and dominant 7(#5) chords on each scale degree.
Number of Unique Augmented Triads
There are only 4 unique augmented triads because the chord is symmetrical. All chord tones are equidistant, dividing the octave into three major 3rds. For example, C+ = CEG#, E+ = EG#C, and G#+ = G#CE.
How to Spell Augmented Triads
The spelling of augmented triads is important for clarity:
B+ is BD#F## (double sharp) instead of BD#G to maintain proper 3rd/5th intervals.
Root determines the chord name, even if the sound is enharmonically identical.
Triad Pairs (Intermediate)
Jazz musicians improvise using triad pairs: two complementary triads from a common scale, often adjacent, providing 6 unique notes.
Example using C Whole Tone Scale (CDEF#G#A#):
C+ = CEG#
D+ = DF#A#
Practice blocking these triads through inversions, ascending and descending.
Augmented Triads as Upper Structure Triads (UST)
C+ can function as a UST over several chords:
V7(#5)
V7alt
Minor-Major 7th chords
Example: C+ over A7b13 ? Right hand: CEG# (UST), Left hand: AE (root+5).
Source Scales for Dominant 7(#13) Sound
Scales that produce a Dominant 7(#13) sound:
Mixolydian b13: 12345b6b7
Phrygian Dominant: 1b2345b6b7
Altered: 1b2b3b4b5b6b7
Whole Tone: 123#4#5#6
Example of C+ upper structure in each scale built on A7 root:
Ab Mixolydian b13: AbBbCDbEbFGb
Ab Phrygian Dominant: AbBbCDbEbFGb
G# Altered: G#ABCDEF
A Whole Tone: ABCDEF
C+ UST Over Other V7(#13) Chords
C+ works as a UST for C7(#13), E7(#13), and Ab7(#13). Roots of these chords outline an augmented triad: CEG#.
Augmented USTs for Lydian Dominants
Lydian Dominant Scale: 123#456b7
Example: D Lydian Dominant = DEF#G#ABC
C+ appears naturally in this scale and can be used as a UST.
Augmented USTs for Minor-Major 7th Chords
Am(maj7) using C+ UST:
Right hand: CEG#
Left hand: AE (omit the G# in LH if already in RH)