To experience the sonic complexity of São Paulo’s rail transport, it is necessary to combine numerous and varied sound references which represent the specific characteristics of different areas of the city. Most of the time city dwellers do not perceive the extent of these differences as they become acclimated to familiar routes, repeated daily. One can live a long time in São Paulo and travel only on one or two train lines, never having been on the other lines. 


R$4.00 enables the discovery of new paths, sounds and ambiences, stimulating the auditory imagination of the listener to construct different relationships between sound and space, allowing the interactor to experience the unknown or the forgotten by giving them access (in a new setting that stimulates attentive listening) to a varied range of sounds and noises that are drowned out daily.


As shown earlier, trains and subways exhibit different patterns in the sounds of their very movement, in the sound warnings and signals, and the audible behavior of passengers and vendors. These differences can be perceived clearly when one is listening more closely. Thus, by subverting the order of urban sound importance, this work allows for a careful hearing of a sound universe that is always present around us but which usually streams by without receiving due attention.