| Résumé |
In this paper we present an overview of gestural capture strategies for
composers/performers wishing to develop work in the area of gestural
controllers. Our objective is to relate the choice of a sensor or the
design of a new gestural interface to the qualities of the gesture(s) one
wishes to "capture." Whether using an isolated sensor or designing a
completely new gestural interface system, our goal is to create a framework
in which one can make intelligent decisions about the ergonomic, practical,
and ultimately artistic uses of gestural controllers.
In order to do so, we begin by discussing the notion of a generic "virtual
musical instrument." We consider this to be an instrument in which the
gestural controller is independent from the sound production (synthesis)
component, divided into the following components:
1. Gestural input
2. Gestural controller (primary feedback to user)
3. Mapping layer
4. Sound Production (secondary feedback to user)
Beginning with the gestural input, we critically summarize and relate some
of the available work--sometimes contradictory--that has been done to
establish classification schema for different types of gesture. After
synthesizing these differing approaches into a general framework, we
proceed by considering the relationship of gestures to sensors and to
desired musical function, discussing properties of sensors and their
appropriateness for different applications. The theoretical framework is
related to a sensor classification system developed in IRCAM's pedagogy
department as an aid for finding the best technological solution for a
specific musical need.
The mapping layer is presented by demonstrating some of the work the
authors have done at IRCAM towards implementing a more expressive wind
controller. Using a three-tier system of mapping strategies, we demonstrate
how the mapping layer is the crucial key in turning gestural sensors into
musical tools. Using a standard WX7 MIDI wind controller, we apply
different mapping strategies to create an expressive instrument that more
accurately captures the expert gestures of a wind instrumentalist. The
system is demonstrated using a real-time additive synthesis timbral space
running in FTS, IRCAM's real-time signal processing system.
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