Lesson 21 Dominant and Leading-tone seventh chords

Lesson 21 Dominant and Leading-tone seventh chords

Part I - The Dominant seventh Chord

The dominant seventh chord is by far the most used seventh chord, because it contains the leading tone. and for voice leading it is better than just the dominant (V) chord.  

 Fig.1 dominant seventh chord

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Part II - Inversion of seventh chords

Inverting the seventh chord os most often done to avoid awkward voice leading.

 Fig.2 inversion of seventh chords

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Part III - Voice leading with 7th chords

Notice how the 5th of the chord (D) is left out for voice leading purposes.

 Fig.3  voice leading with seventh chords

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Part IV - Fully diminished seventh chords
Like the vii° being a substitute for the V, The vii°⁷ can be a substitute for the V⁷.  This is because they have so many notes in common:
In C Major

V⁷ -        G B D F
vii°⁷ -        B D F A

Fig.4 fully diminished seventh chords

Listen: