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Section 21.6 Descending Chromatic Bass Lines

A common musical pattern is the descending chromatic bass line (\(\hat{1}\) –\(\hat{7}\) –♭\(\hat{7}\) –\(\hat{6}\) –♭\(\hat{6}\) –\(\hat{5}\) ). Composers harmonize descending chromatic bass lines in different ways, sometimes with secondary chords, borrowed chords, and augmented sixth chords. Below are some examples from the past four centuries.

Figure 21.6.1 Henry Purcell, Dido and Aeneas, Z. 636, “When I am laid in earth” (Dido's Lament) (1688)
Figure 21.6.2 J.S. Bach, Mass in B minor, BWV 232, Crucifixus (1733)
Figure 21.6.3 Beethoven, 32 Variations in C minor, WoO 80 (1806)
Figure 21.6.4 George Harrison, “While My Guitar Gently Weeps” (1968)
Figure 21.6.5 Jimmy Page and Robert Plant, “Stairway to Heaven” (1971)
Figure 21.6.6 Steven Tyler, “Dream On” (1973)
Figure 21.6.7 Robert DeLeo and Scott Weiland, “Interstate Love Song” (1994)
Figure 21.6.8 Christina Perri, “Jar of Hearts” (2010)

Below is a table comparing the harmonizations of these descending bass lines.

Bass Line \(\hat{1}\) \(\hat{7}\) ♭\(\hat{7}\) \(\hat{6}\) ♭\(\hat{6}\) \(\hat{5}\)
Purcell \(\left.\text{i}\right.\) \(\left.\text{V}^{6}\right.\) \(\left.\text{V}^{4}_{2}\middle/\text{iv}\right.\) \(\left.\text{IV}^{6}\right.\) \(\left.\text{iv}^{6}\right.\) \(\left.\text{V}\right.\)
Bach \(\left.\text{i}\right.\)–\(\left.\text{vii}^{\circ}{}^{4}_{3}\middle/\text{V}\right.\) \(\left.\text{V}^{6}\right.\) \(\left.\text{vii}^{7}\right.\)–\(\left.\text{vii}^{\circ}{}^{4}_{3}\middle/\text{iv}\right.\) \(\left.\text{IV}^{6}\right.\) \(\left.\text{iv}^{6}\right.\)–\(\left.\text{Fr}^{+6}\right.\) \(\left.\text{i}^{6}_{4}\right.\)–\(\left.\text{V}^{6}\right.\)
Beethoven \(\left.\text{i}\right.\) \(\left.\text{V}^{6}\right.\) \(\left.\text{V}^{4}_{2}\middle/\text{iv}\right.\) \(\left.\text{IV}^{6}\right.\) \(\left.\text{Ger}^{+6}\right.\) \(\left.\text{i}^{6}_{4}\right.\)
Beatles \(\left.\text{i}\right.\) \(\left.\text{i}^{4}_{2}\right.\) \(\left.\text{IV}^{6}_{5}\right.\) \(\left.\text{VI}\right.\)
Led Zeppellin \(\left.\text{i}\right.\) \(\left.\text{III}\right.\)\(\left.\text{}^{+M}\right.\)\(\left.\text{}^{4}_{3}\right.\) \(\left.\text{i}^{4}_{2}\right.\) \(\left.\text{IV}^{6}\right.\) \(\left.\text{VI}^{M7}\right.\)
Aerosmith \(\left.\text{i}\right.\) \(\left.\text{i}^{4}_{2}\right.\) ♯\(\left.\text{vi}^ø{}^{7}\right.\) \(\left.\text{VI}^{M7}\right.\)
S.T.P. \(\left.\text{i}\right.\) \(\left.\text{V}^{6}\right.\) \(\left.\text{V}^{4}_{2}\middle/\text{iv}\right.\) ♯\(\left.\text{vi}^ø{}^{7}\right.\) (\(\left.\text{VI}\right.\))
Perri \(\left.\text{i}\right.\) \(\left.\text{V}^{6}\right.\) \(\left.\text{i}^{4}_{2}\right.\) \(\left.\text{IV}^{6}\right.\)
Table 21.6.9

For the harmonization of scale degree \(\hat{6}\) , remember that the concept of ♯\(\left.\text{vi}^{\circ}{}\right.\) was introduced when Roman numerals in minor were introduced. The notes of the ♯\(\left.\text{vi}^ø{}^{7}\right.\) chord belong to the melodic minor scale.