We can now take one of these models or paradigms and structure the outline for an exposition. Remember that the answer enters as the subject cadences.
We will use the 5-6-5-4-3 paradigm. As we saw earlier, this requires a Tonal answer – where the first note is 1 in C and 5 in G to accommodate for the evaded cadence.
The top voice lands on 7 of the original key when the subject begins in measure 4 – so that second counterpoint (or countersubject) should probably be a Soprano Clausula, most likely doubled with syncopation (7-8-7-8)
Now we can go back to measure 3 and add a similar Soprano Clausula in the key of G major to the middle voice.
Finally, we can add a tenor clausula as the second counterpoint (or countersubject) in the middle voice. We can use Rule of the Octave to determine that it should start on F (a 6/3 chord over A) and then descend F-E-D-C.
We can now try to experiment with some diminution of each clausula to create a recognizable subject and countersubjects.
A few rhythmic considerations:
- We need some unique recognizable durational pattern for the subject. In slower fugues and those more related to ancient styles, this will often be a dotted note. In faster fugues a short rest on the downbeat is very common.
- In faster fugues the materials will often outline the full harmony (arppeggiation) – at least in the head of the subject. Usually subjects do not exceed an octave in order to not take up too much of the range.
- Repeated notes can create recognizable motives.
- Directional diminution is often used in countersubjects
Here is a first attempt at adding simple diminution to this exposition outline. It definitely satisfies constraints 2 and 3 (stylistic and motivic) but might contradict the harmony at times. We can see these contradictions if we add figures.
Another option would be to dot the second note of the original outline and create some suspensions
We can also try to write a faster subject that follows the same outline:
- Starting with an 8th rest
- Using some repeated notes
We can also use figured bass to check how well we are fulfilling the harmonic constraints:
And we can generate some invertible counterpoint options:
Some resources:
