Chapter Nine Triads in Second Inversion

Triads in Second Inversion

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  It is only partly true that second inversion triads are used the same way as first inversion
  
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    Bass arpeggiations
    
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    Substitutes for the root postion
    
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  Second inversion triads are NOT used as substitutes for the root position because….
  
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  Second inversion is considered to be a much less stable sonority than either of the other two bass positions
  
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  For centuries, P4 is considered a dissonance if the lowest voice in the texture was sounding the bottom pitch of the P4
  
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  Diminished and augmented triads would also contain dissonant intervals above the bass (an +4 and a ^o4, respectively)
  
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  It is used in bass arpeggiations as well as in several other contexts
  

Correct Implementation of the Chords

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  Bass Arpeggiation and the Melodic Bass
  
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    Six-four chords may come about through a bass arpeggiation involving a root position, a first inversion triad, or both
    
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    Take into account such factors as metric placement, duration, register
    
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    Can be formed through a melodic bass (bass is usually in a supporting role)
    

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  Cadential Six-Four
  
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    I – V progression (cadential six-four)
    
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    I does not represent a tonic triad, even though it contains all the notes of a tonic triad
    
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    See example 9-4, the chord progression is I-ii-V-I, NOT I-ii-I-V-I
    
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    Some instructors prefer cadential six-four written as V rather than I – V because the pair of chords together have a dominant function
    
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    The voice leading into and away from the cadential I is usually smooth
    
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    The resolution of the I to V (or V7)
    
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      1^st move down to 7^th
      
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      3^rd move down to 2^nd
      
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    Cadential I occurs either on a stronger beat than the V, or on a stronger portion of the beat
    
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    In triple meter (e.g. time), the I will frequently appear on the normally week second beat if the V occurs on the third beat
    
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    Most dramatic demonstration of the delaying character of the cadential I is found at the cadenza of many solo concertos. (Orchestra stops on I  soloist cadenza  reaches V chord at the end of the cadenza as a single note or a trill  simultaneously with the orchestra resolve to I)
    

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  The Passing Six-Four
  
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    Second inversion triads are frequently encountered harmonizing the middle note of a three-note scalar figure in the bass
    
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    The figure may be ascending or descending
    
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    Any triad may be used as a passing six-four, BUT……
    
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    V or I are most commonly used
    
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    Falls on the weak beat
    
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    Typically features smooth voice leading
    
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    Some theorists prefer not to assign a roman numeral to passing six-fours because of their weak harmonic function
    
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    Voice exchange (chapter 7, 321/123) and parallel sixths are commonly found in passing six-four chords
    

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  The Pedal Six-Four
  
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    One way to elaborating a static root position triad is to move the 3^rd and 5^th of the triad up by step and then back down to their original positions. The sonority that results is a six-four chord
    
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      I – V – I change to I (IV I – V (I ) V - I
      

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  Some theorists call it an embellishing or stationary six-four
  
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  The roman numeral of a pedal six-four is put in parentheses to indicate its weak harmonic function, for example 1 – (IV) – I or V – (I ) – V
  
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  Exceptionally, the bass may move after the six-four chord and before the return of the root position triad (example 9-12)
  
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  Pedal six-fours are occasionally seen in lead-sheet notation (example B – E/B – B )
  

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  In a four-part texture
  
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    the bass (5^th of the chord) should be doubled
    
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    The other voices generally move as smoothly as possible- often by step- both into and out of the six-four chord
    
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  In a three-part texture
  
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    it is generally best to have all members of the triad present
    
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    Sometimes the root or 3^rd is omitted, in which case the 5^th is doubled