The Sparksichord: Practical Implementation of a Lorentz Force Electromagnetic Actuation and Feedback System

Adam Schmidt, Jeffrey Snyder, Gian Torrano Jacobs, Joseph Gascho, Joyce Chen, and Andrew McPherson

Proceedings of the International Conference on New Interfaces for Musical Expression

Abstract

In line with a sustained community interest in electromagnetic actuation of musical instruments, we describe practical considerations for Lorentz Force actuation in conductive strings, exemplified by the Sparksichord – an augmented harpsichord that uses Lorentz Force actuation, optical feedback, and analog circuitry to sustain vibrations of its brass strings. Electromagnetically-actuated and feedback instruments have grown increasingly popular in NIME, though most systems rely on the use of solenoid-style electromagnetic coils. By running current through the string itself, Lorentz Force actuation offers an alternate arrangement of magnets and wire that can afford new modes of interaction, a broader frequency response, and cheaper implementation. We aim to empower practitioners with a toolbox for designing and building actuated instruments of this style and describe our specific implementation for this instrument.

Citation

Adam Schmidt, Jeffrey Snyder, Gian Torrano Jacobs, Joseph Gascho, Joyce Chen, and Andrew McPherson. 2025. The Sparksichord: Practical Implementation of a Lorentz Force Electromagnetic Actuation and Feedback System. Proceedings of the International Conference on New Interfaces for Musical Expression. DOI: 10.5281/zenodo.15698857 [PDF]

BibTeX Entry

@article{nime2025_38,
 abstract = {In line with a sustained community interest in electromagnetic actuation of musical instruments, we describe practical considerations for Lorentz Force actuation in conductive strings, exemplified by the Sparksichord – an augmented harpsichord that uses Lorentz Force actuation, optical feedback, and analog circuitry to sustain vibrations of its brass strings. Electromagnetically-actuated and feedback instruments have grown increasingly popular in NIME, though most systems rely on the use of solenoid-style electromagnetic coils. By running current through the string itself, Lorentz Force actuation offers an alternate arrangement of magnets and wire that can afford new modes of interaction, a broader frequency response, and cheaper implementation.  We aim to empower practitioners with a toolbox for designing and building actuated instruments of this style and describe our specific implementation for this instrument.},
 address = {Canberra, Australia},
 articleno = {38},
 author = {Adam Schmidt and Jeffrey Snyder and Gian Torrano Jacobs and Joseph Gascho and Joyce Chen and Andrew McPherson},
 booktitle = {Proceedings of the International Conference on New Interfaces for Musical Expression},
 doi = {10.5281/zenodo.15698857},
 editor = {Doga Cavdir and Florent Berthaut},
 issn = {2220-4806},
 month = {June},
 numpages = {12},
 pages = {268--279},
 title = {The Sparksichord: Practical Implementation of a Lorentz Force Electromagnetic Actuation and Feedback System},
 track = {Paper},
 url = {http://nime.org/proceedings/2025/nime2025_38.pdf},
 year = {2025}
}