Sergi Jordà: reacTable*

Artist(s):

• Sergi Jordà

Collaborators:

• Martin Kaltenbrunner -
  • Universität Pompeu Fabra
• Günter Geiger -
  • Universität Pompeu Fabra
• Marcos Alonso -
  • Universität Pompeu Fabra

Title:

reacTable*

Exhibition:

• SIGGRAPH 2006: Intersections

Medium:

Interactive audiovisual tabletop

Size:

10' x 10' x 10'

Category:

• Installation

Artist Statement:

The reacTable* is a state-of-the-art, multi-user electro-acoustic music instrument with a tabletop tangible user interface. Several simultaneous performers share complete control over the instrument by moving physical artifacts on the table surface and constructing different audio topologies in a kind of tangible modular synthesizer or graspable flow-controlled programming language. 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* supports a flexible number of users, both local and remote. In a local collaboration scenario, two or more players can share the same physical objects and their space. This collabora­tive space is only limited by the diameter of the table, but a normal situation involves between two and four players. The collaborative environment can be extended when two or more reacTables* are connected through the net.

Sharing the same virtual space, performers can only move the physi­cal objects (the ones on their local table), but these objects are also projected onto the remote table, and their movement may modify the shared audio threads, which provokes real interactions between dis­placed objects. Therefore, two or more net-connected reacTables* are able to fuse different physical spaces into one only-virtual audio/ visual space. In September 2005, two concerts took place with two connected reacTables*, one in Barcelona (International Computer Music Conference) and the other in Linz (Ars Electronica); four per­formers (two in each location) played the piece Teleson, which was specially composed by Chris Brown for this event.

Technical Information:

The reacTable* hardware is based on a translucent round table. A video camera situated beneath continuously analyzes the table sur­face, tracking the nature, position, and orientation of the objects that are distributed on its surface, which represent the components of a classic modular synthesizer. Users interact by moving these passive objects (no sensors or actuators) and/or by changing their positions, their orientation, or their faces. 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 visual feedback of the state, the activity, and the main characteristics of the sounds produced by the audio synthesizer.

The idea of creating and manipulating data flows is well known in several fields, such as electronics, modular sound synthesis, or visual programming, but the reacTable* is probably the first system that deals with this connectivity paradigm automatically, depending on the type of objects involved and on the proximity between them. By moving these objects on the table surface and bringing them into proximity with each other, performers construct and play the instru­ment at the same time, while spinning them as rotary knobs controls their internal parameters.