ReacTable

The reacTable is a collaborative electronic music instrument with a tabletop tangible multi-touch interface. Several simultaneous performers share complete control over the instrument by moving and rotating physical objects on a luminous round table surface. By moving and relating these objects, representing components of a classic modular synthesizer, users can create complex and dynamic sonic topologies, with generators, filters and modulators, in a kind of tangible modular synthesizer or graspable flow-controlled programming language.

The modular synthesizer mashes up shades of Tron, laser hockey and classic Moogs using open-source reacTivision software and an under-the-hood camera to track blocks that, when added, rotated or moved, combine to produce beeps, whoops and soaring synth lines.

The reacTable's developers say it is the latest in an emerging wave of "tangible music interfaces,"

The instrument was developed by a team of digital luthiers under the direction of Dr. Sergi Jordà. The "Interactive Sonic Systems" team is working in the Music Technology Group within the Audiovisual Institute at the Universitat Pompeu Fabra in Barcelona Spain. Its main activities concentrate on the design of new musical interfaces, such as tangible music instruments and musical applications for mobile devices.

The reacTable intends to be:

collaborative: several performers (locally or remotely)
intuitive: zero manual, zero instructions
sonically challenging and interesting
learnable and masterable (even for children)
suitable for novices (installations) and advanced electronic musicians (concerts)

The reacTable hardware is based on a translucent, round multi-touch surface. A camera situated beneath the table, continuously analyzes the surface, tracking the player's finger tips and the nature, position and orientation of physical objects that are distributed on its surface. These objects represent the components of a classic modular synthesizer, the players interact by moving these objects, changing their distance, orientation and the relation to each other. These actions directly control the topological structure and parameters of the sound synthesizer. A projector, also from underneath the table, draws dynamic animations on its surface, providing a visual feedback of the state, the activity and the main characteristics of the sounds produced by the audio synthesizer.

More info here…
http://en.wikipedia.org/wiki/ReacTable

The reacTable, is wowing festival audiences after it was hand-picked by Björk for use on the singer's summer tour.

The reacTable gets a workout during Björk's June performance of "Pluto" at the Glastonbury Festival in England.
Video: reacTable

ReacTable is not yet available to mere mortal musicians -- but when Björk comes knocking, you don't say no.

The singer particularly liked the visual feedback that lets the audience see how the reacTable makes music.

Bjork has always been into people who come up with something totally fresh, and she really enjoys bringing out things that people haven't seen before and giving a platform to really new ideas.

RWC loves Bjork and the reacTable.