Fully Diminished & Half-Diminished Fully Diminished 7th Chord (o7) has a minor 3rd, diminished 5th A$ m3 F and a diminished 7th from the m3 D bass note (or stacked minor B m3 3rds). They naturally occur GRADE 7 (diatonic) as viio7 in minor keys viio7 in C minor Dr. Declan Plummer Lesson 2: Diminished 7th Chords Half-Diminished 7th Chord (ø7) has a minor 3rd, diminished 5th and a minor 7th from the bass. They naturally occur as viiø7 in major keys and iiø7 in minor keys

viiø7 C major iiø7 in C minor

Diminished 7th chords are used primarily as leading note chords: 2nd mvt, Symphony No.9 in E minor (New World) by Dvořák (9:24) 9:30 • to substitute or decorate the dominant chord • to modulate to distant keys • as a predominant chord (usually viio7/V to V) - dealt with in another lesson

o 4 V 7 I vii 3

o 4 6 ø 6 vii 3 $ 6 i6 I6 D major: I V vi I 4 ii 5 I • The diminished 7th chord may be considered a dominant 9th with Fully Diminished 7ths its root missing. An alternative notation may be used: • A fully diminished 7th chord contains a minor 3rd, diminished 5th and a diminished 7th from the bass note (or stacked minor 3rds). • Chord viio in major keys and chords iio and viio in minor keys are naturally occurring (diatonic) diminished triads, so it’s easy to make them into viio7 Vo9 diminished 7th chords by adding a diminished 7th above the bass note. • The diminished 7th chord may be found in its other inversions. A$ m3 Chromatic Chord F m3 D viio7 in minor keys is B m3 the only time a diminished 7th o$7 chord is diatonic vii in C major Chromatic Chord

A$ m3 C$ m3 F A$ m3 m3 D F B m3 D m3 * It is well acceptable to describe diminished 7th chords in relation to the bass note viio7 in C minor iio$7 in C minor

Resolving Fully Diminished 7ths • There are three dissonant intervals in a diminished 7th chord and they all seek a satisfactory resolution. dim 7 dim 5 dim 5

Start

• As a result, diminished 7th chords tend to resolve to a tonic chord, which is why they also function like secondary dominants. D-F-A$-C$

o4 vii 3 Modulation & Fully Dim7th Chords • When the inversions of a diminished 7th chord are spelt differently (changed enharmonically) they create new diminished 7th chords.

Dim 7th on the leading • Another way in which composers use the diminished 7th chord to modulate is note of E$ (major or minor) to lower any one of its notes (except the 7th), to create a dominant 7th chord.

Dim 7th on the leading enharmonic note of F# (major or minor)

Dim 7th on the leading note of A (major or minor)

• Enharmonic equivalents of diminished 7th chords offer considerable scope for modulation when used as pivot chord. 1st mvt from Beethoven’s Pathétique Sonata 5:33

6 o7 o 4 o4 6 G minor: i V 4 i vii /V V vii 2 V vii 3 i

o 4 G minor: vii 3 viio 4 V viio 4 enharm. 2 3 (F#-A-C-E$ enharm) E minor: vii o 4 i 6 V7 i 6 V9 V7 2 4 4 E minor: (D#-F-A-C#)

could have modulated to E major too

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