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  3. Ch.8.8 Augmented sixth chords - triads

8.8 Augmented sixth chords - triads

 

Category: Harmony | Tags: Chords, Triads

Theory

In this chapter, you will learn that there are two kinds of triads, namely the double-diminished flat-fifth triad and the major flat-fifth triad. Double-diminished flat-fifth and major flat-fifth triad are altered chords. These chords do not come naturally in a major or minor scale, but are created by alteration of tones. In the examples I show how to make double-diminished flat-fifth and major flat-fifth triads. You are goning to make them yourself in the exercises.

1. What is a double-diminished flat-fifth triad?

Double-diminished flat-fifth triad is derived from alteration of the fourth degree (IV). This results in a triad with a diminished third and a diminished fifth. This triad is called a double-diminished flat-fifth triad.

Double-diminished flat-fifth triad in the major scale

In the major scale, a double-diminished flat-fifth triad is made by raising the root and lowering the third.

 

Examples

How to make a double-diminished flat-fifth triad in C major?

note example

Double-diminished flat-fifth triad in the minor scale

In the minor scale, a double-diminished flat-fifth triad is made by raising the root (the third is already lowered).

 

Examples

How to make a double-diminished flat-fifth triad in C minor?

note example

 

Examples

Which tones do you get if you make double-diminished flat-fifth triads on the natural notes?

note example

2. The Italian sixth chord

Double-diminished flat-fifth triad only occurs in first inversion. The lowest tone is the lowered third, the highest tone is the raised root. The distance between these two tones is an augmented sixth. The first inversion of a double-diminished flat-fifth triad is called an augmented sixth chord (A6) or Italian sixth chord (It6).

Augmented sixth chord in the major scale

In C major, the fourth degree (IV) is comprised of the tones F - A - C. By raising the root and lowering the third we get F# - Ab - C, this is a double-diminished flat-fifth triad. The first inversion is Ab - C - F#, this is an augmented sixth chord or Italian sixth chord.

 

Examples

How to make an augmented sixth chord in the C major scale?

note example

Augmented sixth chord in the minor scale

In C minor, the fourth degree (IV) is comprised of the tones F - Ab - C. By raising the root we get F# - Ab - C, this is a double-diminished flat-fifth triad. The first inversion is Ab - C - F#, this is an augmented sixth chord or Italian sixth chord.

 

Examples

How to make an augmented sixth chord in the C minor scale?

note example

3. What is a major flat-fifth triad?

Major flat-fifth triad is derived from alteration of the second degree (II). This results in a triad with a major third and a diminished fifth. This triad is called a major flat-fifth triad.

Major flat-fifth triad in the major scale

In the major scale, a major flat-fifth triad is made by raising the third and lowering the fifth.

 

Examples

How to make a major flat-fifth triad in C major?

note example

Major flat-fifth triad in the minor scale

In the minor scale, a major flat-fifth triad is made by raising the third (the fifth is already lowered).

 

Examples

How to make a major flat-fifth triad in C minor?

note example

 

Examples

Which tones do you get if you make major flat-fifth triads on the natural notes?

note example

4. The augmented six-four chord

Major flat-fifth triad only occurs in second inversion. The lowest tone is the lowered fifth, the highest tone is the raised third. The distance between these two tones is an augmented sixth. The second inversion of a major flat-fifth triad is called an augmented six-four chord (A6/4).

Augmented six-four chord in the major scale

In C major, the second degree (II) is comprised of the tones D - F - A. By raising the third and lowering the fifth we get D - F# - Ab, this is a major flat-fifth triad. The second inversion is Ab - D - F#, this is an augmented six-four chord.

 

Examples

How to make an augmented six-four chord in C major?

note example

Augmented six-four chord in the minor scale

In C minor, the second degree (II) is comprised of the tones D - F - Ab. By raising the third we get D - F# - Ab, this is a major flat-fifth triad. The second inversion is Ab - D - F#, this is an augmented six-four chord.

 

Examples

How to make an augmented six-four chord in C minor?

note example

5. Italian sixth chord and augmented six-four chord in practice

In fact, Italian sixth chord and augmented six-four chord are built on the lowered sixth degree. The highest tone of these chords is the raised fourth tone. Both tones are resolving to the dominant, the fifth degree.

Italian sixth chord and augmented six-four chord are always resolving to the dominant, the fifth degree: It6 - V7 or A6/4 - V7.

6. Practise

 

Double-diminished flat-fifth and major flat-fifth triads

Harmony exercise 8d: practise determining the third and fifth of a double-diminished flat-fifth and major flat-fifth triad.

Harmony exercise 8e: practise making double-diminished flat-fifth and major flat-fifth triads on the natural notes.

Harmony exercise 8f: practise making double-diminished flat-fifth and major flat-fifth triads on all notes.

Italian sixth chord and augmented six-four chord

Harmony exercise 8g: practise making Italian sixth chords and augmented six-four chords with given root on the natural notes.

Harmony exercise 8h: practise making Italian sixth chords and augmented six-four chords with given root on all notes.

Harmony exercise 8i: practise making Italian sixth chords and augmented six-four chords on the natural notes.

Harmony exercise 8j: practise making Italian sixth chords and augmented six-four chords on all notes.

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