Gerd Zacher's Die Kunst einer Fuge. Johann Sebastian Bachs 'Contrapunctus I' in zehn Interpretationen, opens with the interpretation 'Quatuor', dedicated to Johann Sebastian Bach. Actually, Bach immediately appears in a double position, a double bind. On one hand, he supplies the 'original' material for Zacher's entire project; on the other hand, he is presented as 'only' one of the ten composers to whom 'Contrapunctus I' is dedicated.
 'Bach himself advocated and practiced organ playing in 'real Quatuor' on three manuals and pedal'. Zacher then presents his first interpretation of this four-part fugue 'à la manière de monsieur Bach'; Bach could have played the fugue in this registration. Because each voice is assigned a different timbre, they can all be clearly distinguished and their development easily followed. 'Quatuor' assumes that each voice in a fugue is equally important; therefore, all should be actualized in an equal manner. The first interpretation introduces, so to speak, the 'given subject'. 'This version represents the most unambiguous exposition of the course taken by the voices. The listener recognizes familiar things, but he is also able to perceive new features without hindrance. Although still at home, he is already on his way'. The listener is still kept close to the 'source', close to the dominant discourse or the dominant representations and ideas, close to the conventional interpretation-praxis. It is the 'first' access to structures that are relatively stable and from which the most venturesome interpretations will have to begin. So, the listener is still at home.But he is also already on his way. How should we understand this important addition? Each performative interpretation transforms that, which is interpreted. Every interpretation contains a double instance of forgetting and remembering; every interpretation adds something to preceding interpretations. However, it also needs to ignore some aspects in its attention to others. Therefore, each repetition (for instance, of a score) is by definition a transformation with the understanding that what is being delivered (the score) is never a given, but rather a task. In other words, it is more about the working than about the work. (Roland Barthes thinks of a text as a 'production' rather than as a 'product'.) Music is always at work; performances and replays are not copies of an original. Re-enactments are not returns; they point us in a forward direction. This post-structuralist notion of repetition is very different from a nostalgic desire for repetition of the same; it breaks with any notion of the original and the copy (cf. Game, p.184).
The listener recognizes 'Contrapunctus I'. He recognizes it, for instance, by the conventional registration, but at the same time he hears it for the first time. Every performance is marked by a certain singularity.
 'Although still at home, he is already on his way'. Could there be more significance to this? Could it relate, for example, to Zacher himself? By playing the fugue as faithfully as possible to the original, Zacher seems to hold on to a way of thinking that highly regards origins. At the same time, however, he challenges this approach, given that the work was (probably) not written for church organ. Baroque expert, Gustav Leonhardt, has established somewhat convincingly that Bach intended Die Kunst der Fuge for harpsichord (cf. Leonhardt. cf. also Dickinson). Zacher, too, then is both still at home and already on his way. However, he himself puts emphasis on his being at home. For instance, with regard to his registration. In his liner notes, he speaks about 'a registration following conventional models'. Only the alto voice that opens the fugue would allow for a double reading. 'Only the alto, as the voice which begins the cycle, is given an element to attract attention'. The registration of the alto is namely an Acoustic 8', formed by the combinations of Nasat 2-2/3' and Octave 4'. In a first reading, the alto may count as male belonging to the Principal family, i.e., as the highest of the three under parts. In a second reading, the alto is the female contralto by the imaginary 8', the fundamental note, and, therefore, the lower top part.
A spectral rumor resonates. The alto as a specter. Let's take a closer look at the registration of the alto voice. An Acoustic 8', formed by the combinations of Nasat 2-2/3' and Octave 4'. '4'' means that the notated note sounds one octave higher. '2-2/3'' refers to a fifth (although not the first fifth in the overtone series). In other words, it is not the fundamental that sounds, but only tones from the overtone spectrum. The overtones produce the fundamental instead of the other way around. The '8'' is only present as a sounding simulacrum. It is not really there. (When two tones are played, one also hears two other tones; the tone that is the sum of the frequencies of the played tones and the tone that is the result of subtraction. The frequency of 4' subtracted from the frequency of 2-2/3' gives 8'.) The Acoustic 8' only resonates in the play of Nasat 2-2/3' and Octave 4', the play of the overtone spectrum. It is there, but it is not really there. A being there of an absent one. A specter. Spectrality. Spectral music uses the overtones of a fundamental. 'If there is something like spectrality, there are reasons to doubt this reassuring order of presents (present-past, present-present en present-future) and, especially, the border between the present, the actual or present reality of the present, and everything that can be opposed to it: absence, non-presence, non-effectivity, inactuality, virtuality, or even the simulacrum in general, and so forth', Derrida writes (Specters, p.39).
 But is the alto the only voice with a deviant registration? When listening to the piece, one does not so much notice the deviating alto as the tenor voice. 'The tenor, as 'taille', is played on the reeds'. But what kind of 'taille' is this? ('Taille' means 'tenor' in French music up to the Baroque period, but it can also mean 'waist'.) Female? In our body-centered culture, the waist is considered the region between the lower and upper part of the body. Although an important link, the female waist in particular should contain the least amount of volume. That is exactly the sound of the tenor in 'Quatuor': somewhat shrill, but also thin. The least clear. Also the softest. In his written comments, Zacher points out that the alto voice deviates from convention, but as one listens, the attention is first attracted by the rather strange tenor. Zacher's registration implies a hierarchical relationship between equal voices. At any rate, the four individual voices can be clearly distinguished, an effect for which Zacher consciously strives. 'The voices are characterized, so that each can at once be recognized by its tone color'. But by doing so, is Zacher not 'already on his way' for the very reason that such a registration goes against the accepted organ praxis?
A distinction can be made between heterogeneous and homogeneous polyphony (cf. Zimmermann, p.218-228). Polyphony may be described as a musical style in which all concurrent voices each possess a somewhat distinct individuality. This individuality is most distinct in heterogeneous polyphony (e.g., Cantus Firmus), where all voices bear a clear mark of their own. In contrast, homogeneous polyphony is mainly characterized by a unification of melodic motives. This is the case when, for example, all the voices have the same subject. (It seems remarkable that the polyphonic ideal of the individualization of voices is undermined and dislocated from within by competing compositional intentions in the urge to repetition and the joy of recognition.) The homogeneity of motives is a distinguishing feature of a fugue. The individual development of the separate voices seems subordinated to the harmonic structure.
It is in conformity with accepted organ praxis that a homogeneous piece asks for a homogeneous registration. Zacher, however, employs a heterogeneous registration for 'Quatuor'. When listening to Zacher's 'Contrapunctus I' in real Quatuor, one is reminded primarily of a four-part fugue with at least two heterogeneous constituents: on one hand, the treble, alto and bass as homogeneously bundled voices, and the tenor as a kind of heterogeneous solo-voice on the other. When we activate Zacher's comments from the liner notes, we could even opt for a three-layered heterogeneity with the alto regarded as a separate voice as well. However, the melodic material, i.e., the subject, is the same for all voices and therefore does not give rise to such audible heterogeneity. Although still at home, Zacher is already on his way. In a subtle way, Zacher introduces a homogeneous piece of music to the field of heterogeneous polyphony. The 'most unambiguous exposition' appears to contain what could be the most obscured ambiguity. In a sense, 'Quatuor' turns out to be just as deviant as the other nine interpretations.