Strauss, Künstlerleben (Artist's Life)

One of the better known waltzes of Johann Strauss, jr., Künstlerleben [Artist’s Life] has a number of features that are similar to those in the even more famous Blue Danube. One of the clearest tonic-with-add6 chords in the Strauss repertoire is in bars 4-5 of waltz 2 (below), and it appears again as the melody line comes back down (bars 12-13). This latter version, with the tonic chord in 6/4 position and acting as a cadential dominant, is more common in Strauss waltzes than the root position version that became the standard in most uses well into the twentieth century.

In the third waltz, the same scalar descending figure has different consequences: a V9 (first box) that resolves directly, a transient Iadd6 that follows, and an ECP (expanded cadential progression) whose ^6 over ii6 participates in the motivation to a very emphatic rising cadence gesture.

The last waltz in the set also makes much of the potential of ^6 for expression and coloration of harmony, starting in the first bar (arrow). Piling things on, Strauss directly resolves V9 (second arrow and bar 6) but with an intervening upper neighbor E6! The tonic as Iadd6 is particularly expressive with its repeated leaps to ^6 (double arrow and bars 6-8). The version of with the tonic chord in 6/4 position appears in bars 12-13. 

After all the above, the second strain is remarkably simple, involving a pair of rising cadences, the second of which even devolves to ^6 over a simple subdominant.