We now move on from imitative practices common in the sixteenth century to the fugue which may be thought of as the eighteenth century equivalent and successor to this tradition. This chapter deals with the basics of writing a fugal exposition from a given subject according to the ‘high Baroque’ technique of Bach, Handel and their contemporaries. First let’s define some of the terms we’ll need:
- Fugue: a surprisingly difficult term to define satisfactorily! Here we’ll deal with the idea of ‘fugue as process’, i.e. how to construct (the first part of) a fugue from first principles.
- Subject: a short tune which forms the melodic basis of the fugue;
- Answer: a transposition of the subject with is also sometimes slightly altered as discussed below;
- Countersubject: a melodic line that is sounded with (and complement) the subject/answer;
- Exposition: the first part of the fugue which sets out introduces each of the constituent voices involved.
- Voices: the separate contrapuntal lines; this term does not necessarily mean singers (though it can) and the number of voices is not necessarily given by the number of parts / musicians involved (though, again, it can). It is perfectly normal for a keyboard fugue (i.e. one player, no singers) to have 3, 4, 5, or 6 ‘voices’, and there are even some fugues for solo violin (which is quite a compositional feat!).
- SATB: Notwithstanding the fact that we’re not necessarily dealing with voices in the sense of singers, it is customary to refer to a four-voice texture with ‘S’ (‘soprano’), ‘A’ (‘alto’), ‘T’ (‘tenor’), and ‘B’ (‘bass’) for those ‘voices’, working from highest to lowest. The ranges need not exactly match those of the vocal parts.
Structure / Voice Entries
Basically, the fugal exposition works as follows:
|Voice 1||Subject||Countersubject||Free part|
One voice begins with the subject; then the next voices enters with the answer while the fist continues with a countersubject and so on.
Note that we’re numbering the voices here simply on the basis of their successive entries. While it is perfectly common for the voices to enter in order from highest to lowest or lowest to highest, this is not strictly necessary. What you will commonly find in the repertoire is an avoidance of inner parts entering last; specifically: at the moment of a new part entering, it should be the highest or lowest voice at that stage. That leaves us plenty of options. For instance the order of voice entries in a four voice fugue could be:
- In register order from highest to lowest (SATB), or vice versa (BTAS);
- Starting in the middle with the alto: ASTB, ATSB, ATBS,
- Starting in the middle with the tenor: TBAS, TABS, TASB.
Any further subjects / answers entering (beyond the total number of voices) are described as ‘redundant’ entries.
When considering how to handle a subject, look at its structure and character.
The structure of a subject can often be thought of in three parts. As in many tonal contexts this charts a course from a distinctive opening to a generic cadence:
- ‘Kopf’ (literally ‘head’) motif: an opening gesture;
- ‘Fortspinung’: prolongation which may include sequence and/or motor rhythm;
Types of character include the:
- ‘Toccata’ style which has a moto perpetuo rhythmic feel, is often chromatic, and may have irregular rhythmic placing.
- ‘Ricercar’: deriving from the plainsong / motet tradition, this is slow moving, has an antiquated feel, and makes extensive use of suspensions.
We distinguish between two types of answer: ‘Real’ for an exact transposition, and ‘tonal’ for one that has been altered further.
We need a tonal answer if the subject:
- starts on scale degree 5 or otherwise uses it prominently at the outset. In this case, we must adjust the transposed version such that 5 is not transposed up to scale degree 2, but instead to scale degree 1.
- includes any other V-I suggestion at start. Prominent dominant note in subject becomes tonic note in answer, so T → D progressions often become D → T and vice versa.
- modulates. In this case, split subject into two phrases, one in each key, and adapt accordingly. If the subject modulates at its end to the dominant, the answer must modulate back to the tonic
In all cases, we seek to make minimal adjustment such that the subject and answer are still as alike as possible, and both make melodic sense.
Try working up a skeletal version of your countersubject first before. It’s frustrating to dash off a lovely tune and then realise that it doesn’t fit. Additionally, sketch the version that will go with the answer at the same time as the version that goes with the subject. It’s just as frustrating to write a countersubject that works beautifully with the subject, but which the answer makes harmonically nonsensical.
Hold on, harmony? Yes indeed! Countersubjects are melodies but they only work if they make sense harmonically as well. To that effect, remember that your countersubject will first appear in a two-voice passage so consider how best to outline clear, larger harmonies (triads and sevenths) with only two voices.
You may wish to set yourself the additional constraint of a countersubject which is invertible at the octave – basically, one which can appear above or below the subject and still work. In this case, again work on both versions as you go, and specifically make sure to:
- avoid 5th because 5th invert to 4ths which have special rules in two-voice writing. Stick to unisons (/ octaves), thirds (/ sixths), and in the case of 7th chords, also 2nds (/ 7ths). The 5th is not a problem in the free part, so ‘reserve’ that note as the completion of the chord, and use it there.
- similarly avoid 4-3 suspensions because the first note is not dissonant when inverted (5-6). Instead, use 7-6 and 2-3 suspensions (which invert to each other).
To create your skeletal countersubject, first look for skeletal patterns in the subject. Find the simple, un-embellished form of the subject and treat is as a kind of tonal cactus firms against which to write your counterpoint (skeletal countersubject) which you can then embellish into a more interesting musical line.
When it comes to embellishing, try to:
- Be true to the character of the subject when composing the counter subject;
- Establish complementary rhythmic motion such that one voices moves while the other is stationary;
- Make changes to countersubject when moving between subjects and answers only and exactly where those changes appear in the subject/answer.
Frankly, the idea of a ‘Free part’ is a bit of a misnomer, especially if you’re writing an invertible countersubject because the subject and countersubject will leave your options highly constrained. This part is ‘free’ in the sense that it doesn’t necessarily recur later on, so you might like to think of it as a ‘freer’ part, relative to the even less free subject and countersubject! Alternatively, you can embrace the extreme order, and replace the ‘free part’ with a second regular countersubject which dos recur later.
Your fugal exposition may include short interpolations between the subject/answer entries. We call these ‘links’. Links frequently make use of a melodic idea from the subject, for instance with sequential repetition of a short fragment. They may appear between any or all voice entries, and be of varying lengths.
There are many musical motivations for including one of more link. Links provide an opportunity to:
- change harmony: the end of one subject/answer and the beginning of the next may not match up harmonically; in that case, you can use the link to get where you need to be:
- change register: if you have a continually descending line, for instance, links can be a useful way of resetting the register so you don’t fall off the end of the instrument (or, indeed, audible!) range.
- vary the phrase lengths: if you have a subject of exactly two measures, and just proceed through several voices entering successively, then you may well want to use a link to make the hypermetrical and phrase groupings a little more interesting. That said, the voices should always enter on metrically comparable positions. If your subject comes in on a strong beat, then so should all the subject/answer entries (at least in the exposition). If your subject is anacrustic (comes in on a pick-up) then again, make that consistent.
- dovetail entries: apart from varying the phrase lengths, we can also vary the melodic context in which a voice enters. For instance, if a link develops the ‘Kopf’ motive sequentially, then you can bring in the next subject/answer in seamlessly as it begins with that motiv.
Apart from the specific considerations of the fugue, naturally much of the general practice of writing (tonal) music applies here. Remember in particular to:
- control rhythmic flow: if and when continuous use of a given metrical level has built up (e.g. quarter / eighth / sixteenth notes), consider carefully whether and when it is appropriate to discontinue that motion
- graduate the relative strength of cadences, for instance by controlling the scale degrees in the top and bottom voices.
- Write idiomatically for the instrumentation at hand. Remember to observe practical limitations of hand span, instrument range and the like. This also extends to stylistic matters, for instance, string fugues may be more extrovert and see the two upper parts operate closer together.