5.2 The Passing vii°6

The above video is an analysis of Bach's harmonization of "Ach Gott, vom Himmel sieh' darein" (No. 3 from 371 Harmonized Chorales). Play the video while reading the following description.
  • At 0:12, the analysis below the staff shows that--ignoring for the moment beat two of the first full measure--the root position A minor triad on beat one moves to its first inversion on beat three. Voice leading in the outer voices between beats one and three is by consonant skip (CS) in contrary motion. With the bass A moving to the soprano's previous C, and with the soprano's C moving to the bass's previous A, this kind of "swapping" of notes has been called voice exchange.
  • At 0:18 all four notes on beat two become red and are labeled as nonharmonic tones with respect to A minor, passing tones (PT) in the outer voices and neighbors tones (NT) in the inner voices.
  • At 0:25 the nonharmonic tones on beat two are labeled "vii°6" below the staff since they can also be interpreted as a first inversion leading tone triad. These notes are called a passing vii°6 after the passing tone in the bass.
The video to the left shows that with a passing vii°6
  • the upper voice involved with voice exchange need not be the soprano--in both measures voice exchange is in the alto
  • the progression may go in reverse--in measure 2 the first chord is inverted and the last chord is in root position.

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