An orchestra one can walk through:
Tangible Orchestra is an interactive installation that brings electronic dance music combined with classic instruments to life in a three-dimensional environment. Individual tracks are placed into independent, interactive cylinders that are scattered across the project space. These cylinders have a sensory system that notices people in proximity and play for as long someone is nearby.
The cylinders create an individual listening experience – depending on the number of attending people and their position within the project, different instruments are activated and join the musical piece. Walking through the installation not only means to activate instruments that contribute to the whole piece, but to dub the piece with every step: Depending on the listener’s position and the distance to the speakers that rest within the cylinders, the relative strength of all instruments shifts.
More info: http://www.picaroon.eu/tangible_orchestra.html