Performances of solo keyboard repertoire can sound more or less polyphonic depending on the performer’s use of divergence in expression. Rather than being a purely cerebral experience, this expressive divergence is situated in an ecological relationship between keyboard and player where the gestural dynamics of technique and musicianship overlap. Specific body schemata relating to expressive divergence are therefore foundational to the interpretive freedom of the performer in creating polyphonic expression, and feature transparently in the musical result. This dissertation theorises expressive divergence by examining the embodiment of single voices through the hierarchical structuring of coarticulation, and by showing how these multi-layered gestures combine in the polyphony of expression.
First, polyphony is defined as a term and situated in the centre of a web of meaning formed by its interdisciplinary use as a metaphor, a use that describes responsiveness between subjective agents. The concept of polyphony is then applied to expression in performance. An important feature of single-player polyphony is shown to be embodiment, where each hand (or finger) has its own subjective agency. Reflection about this experience foregrounds the inner relations between thought, body movement, and sound, which leads to a discussion of musical gesture. Such gesture is shown to have a hierarchical structure created by coarticulation (the corporeal subsumption of smaller units of gesture into overarching continuities). Coarticulation depends not only on the musculoskeletal structure of the body, but also on acquired skills and habits (body schemata). It underlies a kind of thinking-through-movement, which embodies and creates musical structure in performance, and forms an essential part of instrument-specific legato playing.
Because coarticulation allows for participation of the whole body in shaping individual voices, it follows that the simultaneous divergence of shape in polyphonic playing involves a certain embodied interaction between voices. The term polyphonic voicing is introduced to describe a quality of performance (rather than a quality of the work being performed) and is contrasted to monophonic and homophonic voicing. In order to investigate polyphonic voicing, this dissertation presents a series of experiments using layered recordings, which in turn provide a springboard for reflection about objectification, agency, spatiality and musical tension. Examples are given of exercises for developing polyphonic expression and its underlying body schemata. These are accompanied with a discussion of the reasons behind each exercise, giving models for readers to use in developing their own exercises. Finally, a recital program is presented, demonstrating how the use of polyphonic expression can function within a normal concert practice across various style periods and in repertoire ranging from simple to complex. In the conclusions, the ideas of the dissertation are once again contextualised in the broad interdisciplinary horizon of polyphony as a metaphor. Single-player polyphonic expression is shown to enact or demonstrate an inner experience of the plurality of subjective agency, an experience made possible by its embodied dimension.