In this section we deal with Augmented, Dominant Seventh Chords, Diminished Seventh Chords, Secondary Sevenths and Neapolitian Chords and their resolutions. The Augment Sixth Chord There are three main types of Augment Sixth Chord (Italian, French and German). They are so named because of the interval from the root being an Augmented Sixth. These are all example of chromatic harmony commonly used from the classical period onwards. These chords are usually built on the flattened Mediant (sixth) of the scale. For example : In C Major or Minor
The Augment Sixth Chords serve two purposes : a ) To add colour to the key. For example chords IVb and Ic or IVb and V Italian Sixth
French Sixth
German Sixth
b ) As a means of modulation. Italian Sixth Modulation For example modulation to the Dominant.
French Sixth Modulation
German Sixth Modulation
Typically this chord would be found in its root position, however it can also be found more rarly in its third inversion. This chord is formed by building a Major triad on the minor sixth of the scale, above this place an interval of an augmented sixth. This chord is used to signify an approaching modulation or a dominant chord resolving to chords V or to the progressions Ic - V. The root of the chord will fall by a semi-tone to the dominant and the augment sixth will rise a semitone to the dominant. The third of the chord usually falls by a semitone. Dominant Seventh Chords and their Resoultions Seventh chords contains four notes and have four possible positions (root, 1st, 2nd, 3rd inversion), for example in C Major.
In C Major the Dominant seventh chord would be formed from the notes of a G Major triad, G being the Dominant (5th Degree of C Major) and the seventh above the root (in this case G). So the seventh would be F in this case. The notes therefore of the Dominant seventh chord on G, would be G, B, D, F. Resolving a Dominant Seventh Chord The Dominant Seventh chord has a stronger effect than V alone beacuse of the leading rising a semitone to the tonic at the same time as the seventh falling a semitone to the mediant (3rd). Chord V7 resolves to chord I
Chord V7 to chord VI
Chord V7b resolves to chord I
Chord V7c resolves to chord I
N.B This is usually treated in the same way as the passing 64 (Ib, V7c, I). Chord V7d resolves to chord Ib
Diminished Seventh Chords This chord is based is built on the leading note of the key with a diminished seventh added.
This chord usually resolves onto chord I, both in the Major and Minor keys thus :
This shows how the leading note B, rises a semitone to the tonic C and the seventh Ab falls a semitone to the dominant G - this is the standard treatment of this chord. Because this chord represents the upper four notes of the dominant ninth chord, it is often used to replace chord V at perfect cadence.
Its most important use is in modulation where it is often used to precede a cadential 64, 53 progression in the new key. For example :
Being a chromatic chord the diminished seventh is often used as a pivot chord to an unrelated key. For example from c minor to a minor.
Being a chromatic chord the diminished seventh is often used as a pivot chord to an unrelated key. For example from c minor to a minor. Secondary Seventh Chords and their resolutions In the same way that adding a seventh to the dominant triad produced the Dominant Seventh chord, a seventh can also be added to any other triad in the scale producing a series of chords known as Secondary Sevenths (please note the dominant seventh chord is not usually classed as a secondary seventh).
Resolving a Secondary Seventh Chord The Seventh always resolves downwards by step to the third of the following chord. If the chord is in first inversion then the bass note should move upwards by step. e.g :
The most important of the secondary seventh chords is that on the supertonic which in its first inversion is called the "Chord of the added sixth". This chord is the same as the subdominant triad with a sixth added and can be used interchangeably.
This chord is often used before a Cadential 64, 63 progression :
Appart from the above progression, secondary seventh chords should be used sparingly. Neapolitian Chords This chord is a chromatic chord. The chord is usually used in it first inversion being based on the chord II, the root and fifth are lowered a semitone to change the effect of the chord dramatically. e.g
This chord is sometimes used in minor keys being used instead of chord IIb. This chord should resolve to chord V or Ic - V(Vd). It is often used at a cadence particularly in the minor key eg.
Modulation This is an example of modulation from C minor to A flat Major.
How to find the root of a chord To find the root of a chord in open position (1) bring all the notes to their closest, close position (2) and then reduce all the intervals to thirds (3). This chord is C major first inversion.
The same method applies to seventh chords
Triads in Root Position are made up of two thirds, sevenths in Root position are made of three thirds. If only thids are present in the triad when in its close position, then its in root position.
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