freeze-frame focus the attention on urban empty spaces, the interstitial areas where energies lie conceived, tensions develop, "the places in which movement goes on" (Gilles Deleuze). The curve walls of freeze-frame represent two flows that slide parallels one to the other at high speed. Their original indifference is under discussion when their course skirts an urban empty space. As a consequence, their trajectories comes into contact with a new field of forces and they become deformed, intersected, their speed decrese. freeze-frame take a photograph at the instant the energies are melted together, the tracks of the flows give the shape of an open space continuously mutating inside of which the man penetrates and walks, discovering new relationships. Therefore freeze-frame is a snapshot, an urban filter of sounds and movements. The different nature of the two flows is represented by the materials that compose themselves (wood, Cor-ten iron) and by the different deformation processes that they undergo as a result of their fusion (elasticity-rarefaction, porosity-corrosion). Their various natures, and consequently a different reflection degrees, contribute to develop an experience always different influenced by the point in which the listener is located