In the installation Altroparlanti, a video projector projects two beams of light on a wall, at the center of which two loudspeakers are hanged. The beams of light form two disks that move on the wall and when these touch the extremities of the wall on the sides and on the ground, the disks bounce back as if they encountered a physical obstacle. The movement of the disks of light is similar to the one of a tennis ball, which trajectory is modified by the obstacles that it encounters in its path. When the disks, during their trajectories, meet one of the two loudspeakers, these emit the sound, previously recorded, of a tennis ball hitting their surface. By crisscrossing the visual and the acoustic field, according to a seemingly causal principle, a short-circuit between the visual perception and the aural one that we perceive occurs, weakening our confidence in our experience of reality, even if only for an instant.