Composing over a Ground Bass
A good place to begin studying tonal composition is by making use of the grand old practice of the Ground Bass. Turn to your Burkhart anthology to p 32 and notice the basslines listed there (Burkhart refers to them as "stock basses.").
The Ground Bass was a simple and widely used practice over much of Europe during the time of the Renaissance. It involved a repeating bassline which formed a harmonic progression, with chords voiced as root position triads over the bass. While there were many variants, we are going to work with one particular ground bass, which had the following repeating bassline:
This was known as the passamezzo and was the basis for hundreds of composed and, no doubt, also improvised dance tunes during the Renaissance. What I love about this is the way it lives in the borderland between modality and tonality.
For our purposes, it is a good beginning for harmonic composition because the harmony is simply made of triads over the bass, with no inversions. The movement of the G to the F clearly shows a modal style (a G minor triad moving to an F major triad, then back to G minor), but when the bassline shifts to the D, often the chord is harmonized with an F#, reflecting the tonal trend towards a major dominant triad in a minor key (V-i). In the second measure there is shift up to the relative Tonic major (in this case, Bb major), in which the following F major triad has a dual function: as the dominant of the Bb but also as the VII triad in G minor, as before. The progression ends with a quickened harmonic rhythm back to G minor with a i V i cadence.
Here are four examples from the authentic recordings of the period.
This one, which you need to hear in the key of Eb minor, follows the pattern quite closely. You can imagine this in Eb by simply reading the ground bass template in the treble clef and changing the key to Eb minor.
The next example uses the same progression, only you should notice that the final chord of each repetition is voiced as a major, not a minor triad. The performed key is in D minor, but it is slow and you should be clearly able to hear the progression: i minor, followed by VII major, followed by i minor. Then the III major, the VII major, concluding with i minor, V major and then I major.
Example three is an interesting variation, a reversal of mode. The I chord is voiced as a major triad, but the V chord in the first measure is voiced as a minor triad. Notice the change in affect here. Also, this version does not move to the III chord, but basically cycles around in variants of the first measure. This is a short excerpt, so play it a couple of times until you can hear the varation.
This final variant, in the key of C, uses this variation on the bass line:
It is a combination of the more modern progression with the older, modal one. A clear I IV I V I progression in the first measured is followed by a modal I VII I V I progression in the second measure. Listen and be sure you can hear this!
NEXT: 2B Realizing Figured Bass.