The Sophtar is a tabletop string instrument with an embedded system for digital signal processing, networking, and machine learning. It features a pressure-sensitive fretted neck, two sound boxes, and controlled feedback capabilities by means of bespoke interface elements. The design of the instrument is informed by Federico Visi’s practice with hyperorgan interaction in networked music performance.

Visi designed the Sophtar and built it in collaboration with Sukandar Kartadinata. At IIL, the Sophtar was extended with actuators, on-board DSP, and machine learning models to make it respond to the player in ways that are not easy to predict yet meaningful and inspiring.

In particular:

• we built an extension that allows the instrument to self-play by means of solenoids;
• we implemented a per-string filtering system to control feedback for specific harmonics for each string;
• we embedded Notochord models to activate the solenoids and tune the filters. This allows the Sophtar to respond to human playing as well as to play itself autonomously using generative approaches.

A study on Sophtar performance and interaction with symbolic models is currently underway.

The solenoids mount designed for the Sophtar by Halldor Úlfarsson and Federico Visi

The Sophtar was presented at the NIME 2024 conference in Utrecht, Netherlands, where it was also part of an improvised session with other instruments; at a dedicated IIL Open Lab; and the IIL Diffractive Sonic Dialogues live performance evening at MENGI in Reykjavik.

Further information on the Sophtar page.

References

• The Sophtar: a networkable feedback string instrument with embedded machine learning. Federico Visi. Proceedings of the International Conference on New Interfaces for Musical Expression 2024 (NIME 2024), Utrecht, Netherlands. DOI: 10.5281/zenodo.13904810, pdf