Three spotlights illuminate the darkened room and reflect on the surface of the 15″ speaker filled with black water, which stands on the bare floor. Three circles of light appear on the opposite wall, changing shape as the speaker’s diaphragm moves. The movement is generated by a sound whose frequency is very low and therefore inaudible. The frequencies of this tonal level are too low for our ear. Nevertheless, they form patterns and waves on the water surface, which refract and scatter the light. Four more speakers are distributed in the corners of the room. They play a multi-channel composition from the sounds of the moving furniture.