II. Counterpoint and Galant Schemas
Ground Bass
Mark Gotham
Key Takeaways
- re-harmonisation of the bass, often to suggest local tonicizations of other keys;
- lively imitation and interplay between the upper parts.
Ground bass compositions are based on a bass line that repeats throughout the piece, usually exactly, or nearly so. Many musicians have found this a compelling compositional constraint for keeping themselves … well … grounded!
How many musicians are we talking about? Well, this practice was highly popular in the Baroque (Purcell was a particularly keen and expert protagonist), it is even more common in popular songs of recent years (see Harmonic Schemas in Pop Music), and there are more than a few examples from in between. In short, it is an extremely and enduringly popular form.
It’s easy to confuse “ground bass” with some other terms; going from broad to specific, the key terms to distinguish are:
- Ostinato: any pattern that repeats throughout a long section or whole work in one voice, like the motto side drum rhythm of Ravel’s Boléro.
- Ground bass: a specific type of ostinato in which a bass line repeats throughout a work or section. The work itself can also be called a ground bass.
- Chaconne and Passacaglia (and international variant spellings such as “Chacony”): sub-genres of the Baroque ground bass. Among their other characteristics, both of these two are in triple meter. Every Chaconne or Passacaglia is also a ground bass, and every ground bass is also an ostinato, but the reverse is not true: not every ostinato is a ground bass, and not every ground bass is a Chaconne or Passacaglia.
This chapter provides some files and instructions to help you explore some of the ways to create effective ground bass compositions. We focus on the Baroque model, and on creating variety through re-harmonizing the same bass in different ways and varying the texture.
Multiple Harmonizations of a Given Bass
Continually using the same repeating bass line throughout could get tedious, and is especially liable to make the harmony extremely static. To that effect, inventive composers find ways to re-harmonize the same bass line to move to other keys, or at least hint at such a move. This often relies on seeing the different ways in which a single interval in the bass could be reinterpreted.
While this might not seem like much to work with, this bass harmonization “cheat sheet” (PDF) shows that there are many ways to re-harmonize bass intervals. It is organized by bass interval: both ascending and descending forms of each interval from minor seconds to tritones. Note that this is supposed to help you work out your options—you definitely don’t need to use all of these! We’ll see below how Purcell uses just a few of these to create harmonic variety in a very long work that’s almost entirely in G minor. We’ll be especially interested in moments where Purcell avoids the main perfect cadence at the start/end of each iteration of the ground, joining two gr