After having worked in film sound for forty years I already knew that sound can create a powerful illusion of a space. The question is if this is only a consequence of the ”audio-visual contract” as described by Michel Chion, or if it works in the non mediated world as well? A cinema audience is prepared to be tricked, or seduced, they have even payed for that. The same applies for someone visiting an art gallery to take part of a piece of sound art. In everyday life however, things are different. Nevertheless our perception of a space and a situation appears to a large extent to be dependent on what we hear, even if it’s contradicted by what we se and by our preconception. When I tried the recording of the subway station in our main hall, st...