September 03, 2016
CategoryBach at my side, Goldberg Variations
The second of the three minor key variations, variation 21 has a tone that is somber or even tragic, which starkly contrasts with variation 20. While the melody produces painful dissonances that sound very modern, the bass line here is one of the most eloquent found in the variations, to which Bach adds chromatic intervals that provide tonal shadings. This variation is a canon at the seventh in 4/4 time; Kenneth Gilbert sees it as an allemande despite the lack of anacrusis. The bass line begins the piece with a low note, proceeds to a slow, chromatic lament bass and only picks up the pace of the canonic voices in bar 3. A chromatic descending bass line is typical of many Bach’s compositions and is in fact very common in the Baroque period.
A similar pattern, only a bit more lively, occurs in the bass line in the beginning of the second section, which begins with the opening motif inverted.