History and Principles of Microtonal Keyboards

Abstract

As real-time computer music performance systems become more widespread, the question of controller design becomes increasingly pertinent. The flexibility of pitch afforded by computer technology suggests the use of new input devices optimized for playing in arbitrary tuning systems. In particular, keyboards are well-suited for polyphonic playing, and there is a legacy of historical microtonal keyboards that can serve as models for controller design. Several motivations for using a microtonal keyboard in computer music can be discerned. The obvious use is for live performance-microtonal music no longer needs to be primarily restricted to tape music on the one hand and to the musiciancraftsman who constructs special acoustic instruments on the other. An equally compelling motivation drives the composer of microtonal music. The real-time aural feedback provided by such a device can open the door to experimentation with many tuning systems whose harmonic resources might otherwise remain untapped. A flexible device for real-time pitch control could also be of use in psychoacoustic research. The greater portion of this article outlines the history of microtonal keyboards, with a view towards establishing the most useful design principles. The final section considers how these principles can be adopted for synthesizer control. A programmable keyboard is particularly useful, allowing a variety of tuning systems and key layouts; software written by the author for such a purpose is described. With such a device, different keyboard layouts can be used to match the tuning system and the nature of the musician's usage, as will be explained. History and Principles of Microtonal Keyboards