Editors’ Notes

When we use digital tools for making music, the properties and parameters of both sound synthesizers and human interfaces have an abstract representation. One consequence of the digital nature of these signals and states is that gesture and action are completely separable from sound production, and the system designer must artificially associate them with sound production in a process commonly called mapping.

The importance of mapping in digital musical instruments has been studied since the 1990s, when several works discussed the role of mapping and many related concepts. Roughly since the mid 2000s, several tools have been offered that facilitate the implementation of mappings, drastically reducing the necessary technical knowledge and allowing a large community to easily implement their ideas. This fact, coupled with the availability of inexpensive sensors and hardware and the emergence of a strong do-it-yourself community, made the time seem right to discuss the main directions for research on mapping in digital musical instruments. This special issue brings together contributions showing the variety of research on mapping and exposing new applications of the field to musical practice.

The first article, “Mapping Control Structures to Sound Synthesis: Functional and Topological Perspectives,” by Van Nort, Wanderley, and Depalle, addresses mapping from two perspectives: as parameter mapping (e.g., associating one type of sensor parameter to one type of synthesis parameter) or as continuous navigation between parameter spaces, and it proposes a unified approach that takes both perspectives into account. It furthermore shows example control structures that are applications of the authors’ framework Library of Maps (LoM) for performing interpolation of parameters between two spaces.

In “A Zoomable Mapping of a Musical Parameter Space Using Hilbert Curves,” Tubb and Dixon concentrate on the design of interfaces for easily navigating large parameter spaces during the ideation or inspiration phase of musical creation. This focus leads them to prioritize ease of use and access to the entire output parameter space over repeatability of control: Users of their system can mark and return to points of interest in a ten-dimensional parameter space using only two dimensions of input.

Caramiaux, Françoise, Schnell, and Bevilacqua address the use of machine-learning techniques for the semi-automatic creation of mappings between performer gesture and existing sonic material. Their article, “Mapping through Listening,” advocates a careful consideration of the perceptual salience of the features of both musical material and physical gestures, grounded in a review and unification of taxonomies by Schaeffer, Gaver, Huron, and others. An appendix describes technical details of the work.

In “The Map and the Flock: Emergence in Mapping with Swarm Algorithms,” Schacher, Bisig, and Kocher take a different approach, using simulations of agent-based flocking and other dynamic systems to provide added interest and complexity to the control of media output for their work.

Lastly, the contribution by Lyon, Knapp, and Ouzounian discusses their approach to mapping between the members of a trio ensemble; their concept of “digital musical instrument” includes sonic material contributed by the violinist, a “biomusician” wearing various sensors, and a laptop performer. Even if mapped in a simple one-to-one manner, the sensor data generated by the biomusician exhibits complex interrelationships due to the dynamics of the underlying human body.

Although the insights and discussion of these authors is of course invaluable, many of the software tools discussed are also publicly available for experimentation and use by readers. Specifically, the high-level tools ISO Flock (Schacher, Bisig, and Kocher) and Sonic Zoom (Tubb) are available both in application form and as source code, and Caramiaux et al.’s gesture variation follower library is also freely downloadable for use in C++ projects.

Finally, while discussion of mapping concepts and approaches is sometimes necessarily quite technical, in these contributions the discussion is firmly grounded in musical practice. The mathematical formulation presented by Van Nort, Wanderley, and Depalle is used to describe—from a performer’s perspective—the mapping approaches they have used for controlling live granulation effects using a Wacom tablet. Schacher and co-workers discuss the use of their tools and approaches for designing interactive installations and artistic work for human dancers and simulated agents...