INVISI Ltd brings together a dozen sound designers who design sound objects with the desire to make people aware of what is invisible to the naked eye, through sound and music. «We make visible the "Invisible"». Two installations are presented in the courtyard of the National Archives: a xylophone and a sound bench. At the borders of art, design and music, the xylophone works thanks to the natural energy of gravity: when falling on the steps, the ball plays music. Sometimes she escapes from the steps and falls on the ground, this movement makes us want to catch her, as if she were alive.