Pencil Fields: An Expressive Low-Tech Performance Interface for Analog Synthesis

I present a novel low-tech multidimensional gestural controller, based on the resistive properties of a 2D field of pencil markings on paper. A set of movable electrodes (+, -, ground) made from soldered stacks of coins create a dynamic voltage potential field in the carbon layer, and another set of movable electrodes tap voltages from this field. These voltages are used to control complex sound engines in an analogue modular synthesizer. Both the voltage field and the tap electrodes can be moved freely. The design was inspired by previous research in complex mappings for advanced digital instruments, and provides a similarly dynamic playing environment for analogue synthesis. The interface is cheap to build, and provides flexible control over a large set of parameters. It is musically satisfying to play, and allows for a wide range of playing techniques, from wild exploration to subtle expressions. I also present an inventory of the available playing techniques, motivated by the interface design, musically, conceptually and theatrically. The performance aspects of the interface are also discussed. The interface has been used in a number of performances in Sweden and Japan in 2011, and is also used by other musicians.