In order to realize this
project, I started writing a rather large and complex computer program,
which eventually became what is technically known as an expert system.
This composition program consisted of four modules:
- 1.: Analyzer
- 2.: Fugue-writer
- 3.: Fugue-player
- 4.: Fugue-notator
The first module -the analyzer-
as the name implies, analyzes the given dux. It calculates Markov-chains
for the probability of the note order, figures out some of the aesthetics
of the dux (tonal, modal, atonal, serial..., metrum, - binary, ternary,
quinternary, mixed -, rhythmical structure, articulation...) and tries
to figure out a set of rules appropriate to handle the dux in counterpoint
and throughout as fugue. Also, this program module calculates a suitable
comes (the counter-subject) and some variations on both dux and comes.
It proposes these to the composer who can accept or reject them. From
these acceptations and/or refusals, the program takes lessons for any
further proposals with regard to this same dux. The second module attempts
to apply the formal structure of the classical fugue to the given and
calculated or derived material. This form is constant and cannot freely
be changed by the user (composer). However, the form is defined in it's
most maximalistic appearance and thus comprises:
- exposition of the dux
- exposition of the comes
- divertimento: motivic
work and variation on dux and comes
- counterpoint / choral
- metrical and tonal variations
on dux and comes
- stretto
- finale with reexposition
of the augmented dux in the bass (pedal) and counterpoint in other voices.
Depending of the intrinsic
properties of the given material, the program will decide which sections
to work out, and which ones to leave out entirely: For instance, not all
duxes allow for an elaborate stretto, nor for a choral section. This way,
the final structure of every composed fugue will and can be quite different.
After having written the first sketch of the fugue, the program plays
it to the composer, who can -again- be the expert to the program and teach
it certain of his own and extra preferences or avoidances. After an unlimited
amount of run -throughs, the program writes to fugue in binary format
to disk, and the fugue is considered to be finished. A third program module
allows the composer a minimal form of interpretation of the thus composed
fugue. It is just a bit more than a simple juke-box program since it allows
the composer to instantly change tempo, dynamics and some of the instrumentation.
Also it can transpose and interchange voices in real-time. I wrote this
module basically to be able to give audiences some idea of what these
compositions sound like, in my own concerts with the Logos-Duo. (Being
only a duo, clarinet and violin, we cannot play 4-voice fugues live in
concerts of course). Also, the fugues can - using this program - be played
on midi- player pianos (Trimpin machines for instance), if organizers
have such instruments available The fourth and last program-modules I
wrote in collaboration with my friend and colleague Geert Logghe, because
it is a more universal kind of program that allows translations of the
binary files generated and used by the previous modules, into DARMS-code.
This DARMS-code can then be fed to standard music notation software. This
way the fugues can be made available to musicians in the form of traditionally
notated scores.
In total, the program took
me about four months of quasi continuous work to write, and it comprises
about 600 rules pertaining to my idea of fugue composition. The code came
out to be just about twice as long, as the totality of all the fugues
I wrote using it. (About 500 pages of code).
Using this first version
of the software, I wrote a first book of no less then sixteen fugues -in
total good for some 3 hours of music and more than 300 pages of full score.
The idea was to present these fugues as strictly abstract music in the
sense as generally J.S.Bach's 'Kunst der Fuge' is taken. As a consequence,
instrumentation is left intentionally open and up to the performers, just
as well as indications with regard to tempos (although here I have some
suggestions in the following notes), dynamics and most elements of traditional
music interpretation. Also, performers are invited to try out any orchestrations-
even varying ones throughout the fugue, as well as meter changes in any
of these the pieces. Also, transpositions can freely be made with maybe
one restriction: the bass part should remain the lowest part, and the
soprano (but this is less stringent) the highest in the fugue. Should
performers want to get transposed parts of any voice in any key or clef,
they are welcomed to ask me.
One last general remark:
in all the fugues as written in this first book, accidentals only
apply to the note they precede!!! Accidentals were not used in
any tonally logical way anyhow. This is merely attributable to some deficiency
of my software so far. Sorry.
PLAY
MIDI FILE
this
fugue is playing on the background...