Harmonic Tension: Augmented Sixth And Diminished Seventh Chords

Augmented sixth chords and diminished seventh chords are complex and dissonant harmonies that are closely related to inversion, tritone substitutions, diminished scale, and dominant seventh chords. These harmonies create tension and movement in music and are often used to create chromatic effects, voice leading, and dramatic moments. Diminished seventh chords, in particular, are characterized by their symmetrical construction, making them highly versatile and useful in various musical contexts.

Dissecting Augmented Sixth and Diminished Seventh Chords

Augmented Sixth Chords

Augmented sixth chords are characterized by their interval structure:

• Root: The fundamental note of the chord.
• Third: A minor third above the root (e.g., C to Eb).
• Fifth: A perfect fifth above the root (e.g., C to G).
• Augmented sixth: A major sixth above the root (e.g., C to A#).

Types of Augmented Sixth Chords:

There are two main types of augmented sixth chords:

1. Italian Augmented Sixth: Contains a major seventh interval (e.g., C, Eb, G, A#).
2. German Augmented Sixth: Contains a minor seventh interval (e.g., C, Eb, G, Bb).

Diminished Seventh Chords

Diminished seventh chords are also characterized by their interval structure:

• Root: The fundamental note of the chord.
• Minor third: A minor third above the root (e.g., C to Eb).
• Diminished fifth: A diminished fifth above the root (e.g., C to Fb).
• Diminished seventh: A diminished seventh above the root (e.g., C to Bb).

Types of Diminished Seventh Chords:

There are three main types of diminished seventh chords:

1. Diminished Seventh: Contains a diminished fifth and diminished seventh (e.g., C, Eb, Fb, Bb).
2. Half-Diminished Seventh: Contains a perfect fifth and diminished seventh (e.g., C, Eb, G, Bb).
3. Fully-Diminished Seventh: Contains a diminished fifth and minor seventh (e.g., C, Eb, Fb, Ab).

Analytical Representation of Augmented Sixth and Diminished Seventh Chords

These chords can be represented analytically using Roman numerals:

• Augmented Sixth Chords: I⁺⁶ or vi⁺⁶
• Diminished Seventh Chords: vii^o7 (diminished seventh), vii^o7/5 (half-diminished seventh), vii^o7/4 (fully-diminished seventh)

Usage in Music

Augmented sixth and diminished seventh chords are often used in classical, jazz, and other sophisticated music styles. They add harmonic richness and create tension and resolution within a chord progression.

Question 1: What are the key characteristics that differentiate augmented sixth chords and diminished seventh chords?

Answer:
– Augmented sixth chords consist of a root note, a major third, a perfect fifth, and an augmented sixth.
– Diminished seventh chords consist of a root note, a minor third, a diminished fifth, and a diminished seventh.
– Augmented sixth chords resolve to major or minor chords, while diminished seventh chords resolve to major or minor triads.
– Augmented sixth chords have a dissonant and unstable sound, while diminished seventh chords have a tense and unresolved sound.

Question 2: How are augmented sixth chords used in music theory?

Answer:
– Augmented sixth chords are often used as part of a deceptive resolution, where the resolution chord is not the expected chord.
– They can also be used to create tension and anticipation in music.
– Augmented sixth chords are common in classical music, jazz, and popular music.

Question 3: What is the relationship between diminished seventh chords and secondary dominants?

Answer:
– Diminished seventh chords can be used as secondary dominants to resolve to other chords.
– A secondary dominant is a dominant chord that is built on a non-tonic degree of the scale.
– When a diminished seventh chord is used as a secondary dominant, it resolves to the dominant chord of the desired key.

Well, there you have it! I know, I know – augmented sixth chords and diminished seventh chords can be a bit of a brain-bender, but they’re also incredibly cool and add a ton of flair to your music. So, if you’re feeling a little adventurous (or just want to impress your friends), give these chords a try. And thanks for reading! I hope you’ll stick around and visit again soon – I’ve got plenty more musical musings to share.