V. Diatonic Harmony, Tonicization, and Modulation

La (scale degree 6) in the bass at beginnings, middles, and endings

John Peterson

Key Takeaways

This chapter discusses the various ways in which composers harmonize La (\hat{6}) in the bass depending on where it’s found within a phrase: beginning, middle, or ending.

  • At phrase beginnings, La (\hat{6}) is often used to prolong tonic in two ways:
    • harmonized with IV6 in the progression I–IV6–V\begin{smallmatrix}6\\(5)\end{smallmatrix}–I (Examples 1 and 3)
    • harmonized with plagal (IV6) in the progression I–(IV6)–I(Examples 2 and 4)
  • At phrase middles, La (\hat{6}) is often used:
    • in a deceptive motion (V(7)-vi) (Examples 5 and 7)
    • to connect the T and strong PD areas, harmonized with vi (Examples 6 and 8)
  • At phrase endings, La (\hat{6}) is often used:
    • to create a (iv6-V in minor) (Examples 7 and 9)
    • as a “stand in” for the expected strong PD note Fa (\hat{4}) (Example 10)

Overview: uses of La (scale degree 6)

So far we’ve seen every scale degree appear in the bass except for La (\hat{6}). In this chapter we see that La (\hat{6}) is commonly harmonized by two chords: vi and IV6. It may show up in beginnings, middles, or endings of phrases, and each location is associated with particular progressions that involve La (\hat{6}) in the bass.

At phrase beginnings

When La (\hat{6}) appears in the bass at the beginning of a phrase, it typically prolongs tonic in one of two ways: (1) using IV6 as a pre-dominant in the progression I–IV6–V\begin{smallmatrix}6\\(5)\end{smallmatrix}–I (Example 1), or (2) using plagal (IV6) in the progression I–(IV6)–I6 (Example 2).

Example 1. Tonic prolongation via I–IV6–V \begin{smallmatrix}6\\(5)\end{smallmatrix}–I in Josephine Lang, Arie.

Example 2. Tonic prolongation via I-(IV6)-I6 in Josephine Lang, Lied.

Using IV6 as a pre-dominant

Writing I–IV6–V \begin{smallmatrix}6\\(5)\end{smallmatrix}–I can be tricky, particularly when IV6 goes to V6 since there is a danger both for parallels and a doubled leading tone. There isn’t one piece of advice that you can follow that will guarantee you avoid problems. When you write I–IV6–V \begin{smallmatrix}6\\(5)\end{smallmatrix}–I, the sopranos Do–Do–Re–Do (\hat{1}\hat{1}\hat{2}\hat{1}) and Mi–Mi–Fa–Mi (\hat{3}\hat{4}\hat{2}\hat{3}) will help, but you’ll need to check carefully for parallels. Using V\begin{smallmatrix}6\\(5)\end{smallmatrix} instead of V6 will also mitigate some of the danger of parallels (Example 3). Note that this progression doesn’t work well in minor, where the bass would create an augmented second from Le–Ti (\downarrow\hat{6}\uparrow\hat{7}). The rare occurrences of this progression in minor raise Le (\downarrow\hat{6}) to La (\uparrow\hat{6}) to avoid the augmented second (Examples 3c and 3d).

Example 3. Writing with I–IV6–V \begin{smallmatrix}6\\(5)\end{smallmatrix}–I.

Using plagal (IV6)

Writing I–(IV6)–I6 is relatively easy (Example 4). Here, remember three things: (1) the bass always arpeggiates down, (2) the most common soprano is Mi–Fa–Sol (\hat{3}\hat{4}\hat{5}), and (3) the other voices should move by step or common tone.

Example 4. Writing with plagal (IV6).

At phrase middles

In the middle of a phrase, La (\hat{6}) shows up in the bass in two ways: (1) to avoid a cadence as part of a deceptive motion (Example 5); or (2) connecting the tonic area to the strong pre-dominant area by arpeggiating Do–La–Fa (\hat{1}\hat{6}\hat{4}), harmonized by vi or IV6 (Example 6).

Example 5. Deceptive motion in Bernhard Henrik Crussell, Clarinet Quartet Op. 7, II, mm. 66-72.

Example 6. vi connecting T and strong PD areas in Bernhard Henrik Crussell, Clarinet Quartet Op. 7, II, mm. 1-4.

Deceptive motion

Deceptive motion most commonly occurs when V(7) moves to vi rather than I, with the bass moving Sol–La (\hat{5}\hat{6}). Less commonly, La (\hat{6}) may be harmonized with IV6 rather than vi in a deceptive motion. Writing deceptive motion with V(7)–vi carries an inherent danger of parallels that can be avoided by doing the following two things (Example 7): (1) resolve Ti–Do (\hat{7}\hat{1}) as you would do normally, and (2) move all upper voices in contrary motion to the bass (i.e. down).

Example 7. Writing deceptive motion.

Deceptive motion vs. Deceptive cadence

Some people use the term “deceptive cadence” to describe what we refer to as “deceptive motion.” Since the progression V(7)–vi avoids a cadence rather than creating one, we find that the term “deceptive cadence” inaccurately describes the progression’s purpose. So we prefer the more neutral description “deceptive motion.”

vi as a weak pre-dominant

Using vi to connect the tonic and strong pre-dominant areas is quite easy to write (Example 8). As long as your upper voices move by step or common tone and you follow typical writing procedures, you should not run into writing issues. Notice that for the phrase model analysis (T/PD/D) labels, the PD label goes on the first strong PD before the cadence, as in Example 6.

Example 8. Writing with La (\hat{6}) connecting T to strong PD area.

At phrase endings

La (\hat{6}) may appear at the end of a phrase in two ways: (1) as part of a phrygian half cadence (Example 9), or (2) harmonized with a pre-dominant chord as part of a push to a cadence.

Example 9. PHC in Franz Schubert, “Die Mainacht,” mm. 1-10.

The phrygian half cadence (PHC)

The is a special kind of cadential phrase ending that occurs only in minor and which involves the progression iv6–V. It’s called “phrygian” because of the half step that occurs when Le (\downarrow\hat{6}) moves to Sol (\hat{5}) in the bass, a sound that’s similar to when \hat{2} moves to \hat{1} in the phrygian mode. The progression carries a danger of parallels and the danger of writing an augmented second between Le (\downarrow\hat{6}) and Ti (\uparrow\hat{7}). These can be avoided if you choose to double Do (\hat{1}) in the iv6 chord (Example 10). Very often, PHCs are approached from i, and are accompanied by the soprano Me–F–S (\hat{3}\hat{4}\hat{5}), as in Example 10.

Example 10. Writing a PHC.

La (\hat{6}) harmonized with a pre-dominant at a cadence

It’s possible to see La (\hat{6}) harmonized with a pre-dominant (usually vi or IV6) at a cadence without the presence of Fa (\hat{4}) in the bass before the cadential dominant (Example 11). This is much less common, however, than seeing Fa (\hat{4}) in the bass harmonized with a strong pre-dominant before the cadence.

Example 11. La (\hat{6}) as “stand in” for strong PD in Josephn Haydn, String Quartet Op. 76, No. 2, I, mm. 1-4.


  • Assignment 1: Includes analyzing bass lines, writing from figures and Roman numerals, harmonizing an unfigured bass, and analysis



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