The Reactable is an electronic instrument developed by Sergi Jordá, Marcos Alonso, Martin Kaltenbrunner, and Günter Geiger. Its design features a tangible tabletop user interface, developed by the Music Technology Group, at the Universitat Pompeu Fabra in Barcelona, Spain. It allows performers to control tangible objects and with their fingers control the system.

The developers presented their instrument in a performance in 2005, two years after the project began. However, the instrument gained a larger audience after the team published three demonstration videos on YouTube in late 2006. More than four million people have seen these videos, including renowned performers such as Icelandic singer Björk. She successfully incorporated the Reactable into her most recent 18-month world tour, “Volta.”

In parallel, the Reactable team performed over 230 presentations and performances in 30 countries between 2006 and 2009. This established it as a widely praised new musical instrument. The Reactable earned the award of “Hot Instrument of the Year” by Rolling Stone Magazine in 2007. Since then, it has won numerous prestigious international awards, including the Prix Ars Electronica Golden Nica for Digital Musics (2008), two D&AD Yellow Pencil Awards (2008), the MIDEM Hottest Music Biz Start-Up Award (2008), and the Ciutat de Barcelona Award (2007).

Construction of the Reactable

The Reactable is essentially a backlit display and appears as a circular transparent table in a darkened environment. A virtual modular synthesizer operates when placing tangibles on the table, and interacts with the visual display via these tangibles or the fingers. Different types of tangibles represent different components of an analog synthesizer. Some of the most used tangibles are audio frequency VCOs, LFOs, VCFs, and sequencers. Also, additional tangibles impact other modules.

Animated symbols such as waves, circles, circular grids, and sweeping lines emerge when an object sits on the table. Some symbols just display what the tangible does, while others allow control of the module with fingertips. A video camera hides beneath the table, pointing at its underside and transmitting video to a computer. Likewise, a video projector is located beneath the table, connects to the computer, and projects video onto the bottom of the tabletop, which can be seen from the upper side.

The audio engine is based on Pure Data and SuperCollider. The tangibles, which have fiducials attached to their undersides, sit on the table. These fiducials are black-and-white pictures of circles and dots in diverse patterns. Via reacTIVision, they determine the function of the specific tangible.

Currently, two versions of the Reactable exist: Reactable Live! and Reactable Experience. Reactable Live is a smaller, more portable version, designed for professional musicians. On the other hand, the Reactable Experience resembles the original Reactable and is suited for installations in public spaces.