"Cooking a Canon with RUBATO~"
Performance Aspects of J.S. Bach's "Kunst der Fuge"
Joachim Stange-Elbe
Forschungsstelle Musik- und Medientechnologie, Universitait Osnabriick
jstangee@ rz.Uni-Osnabrueck.de
and
Guerino Mazzola
Departement de Mathematique et Statistiques, Universit6 Laval/Quebec
and Institut fuir Informatik, Universitit Zuirich
gbm@presto.pr.net.ch
ABSTRACT
We present and discuss an experimental investigation of Johann Sebastian Bach's "Kunst
der Fuge" on the RUBATO analysis and performance platform. Three resultsare presented:
(1) Sonilication of analysis yields an immediate evidence of well-organized metrical
structure. (2) Valid performances of major works of European Music can be construed in a
puzzle paradigm of combinatorial construction rather than in fuzzy metaphors of creativity
and inspiration. (3) Prejudice-free, analysis-driven strategies seem to yield more
interesting performances than strategies which try to reach a preset expressive style-target.
1 Introduction
This paper deals with an experimental investigation of Johann Sebastian Bach's "Kunst der Fuge" on the
RUBATO~ analysis and performance platform described in 110], discussed in [9], [12], and available on the Internet
from [13]. After theoretical groundwork and software implementation we feel that it is now important to elaborate the
experimental paradigm in musicology, and to do this in projects of major relevance to the occidental tradition. We
looked for a musical text with virtually no performance indications such that the work could be done with an utmost
autonomy and exclusively dealing with the symbolic score material.
The main target of this investigation was to make sure that the overall approach which backs RUBATO is a viable
framework to develop full-fledged performances. The results with "Kunst der Fuge" confirm the claim. They were
established during a two-year DFG grant by one of the authors (Stange-Elbe) and can be accessed as audio and MIDI
files on this ICMC's CD and from [19]. Paraphrasing Roman Jakobson's famous definition of the poetic function 15]
we can state that performance comprises projection from the axis of analysis to the axis of expression. RUBATO
operationalizes this projection model such that valuable performance projections can be realized via intuitive puzzlelike constructions.
2 Rational Semantics of Performance
Expressive Performance results from a complex shaping process which is applied to a given musical composition,
typically defined in form of symbolic score data. Thereby, the acoustic output conveys a message which can be traced
back to three main sources: music analysis, emotion, and gesture [15]. These rationales constitute the semantical
background which is expressed in a given performance. Analytical semantics means that we use dynamics,
articulation, agogics. and intonation to communicate analytical facts of harmonic, melodic, rhythmic, or contrapuntal
nature on a rhethoric level. Emotional semantics shapes performance for a direct emotional message. Gestural
semantics deals with expression of facts from physical movement (typical example: the final retard which has been
modeled by mechanical kinematics, see 17]).
In human performance, all three rationales are simultaneously present, however in different degrees and
depending on the precise musical situation. Accordingly, performance research has focused on all three mechanisms,
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