The concepts of near and far sounds can be expressed in different ways by simply changing the intensity of the sound itself. Hlemmur in C is a project of Pall Thayer made ​​at the conference 'Rethinking the Interface Between Human Creativity and Technology' that seeks to realize this principle through the interaction with the urban territory. Through a minimal interface in java is displayed tracking of two taxi just from 'Hlemmur', an area of ​​the Icelandic capital. To detect the proximity or lontanza from a predetermined point are obviously two GPS devices, while the sound is represented by a MI (ie a C in the notation Anglo-Saxon) constant that changes of tone as that the two cars vary their distance. A unique sound that reflects the changes in motion, as if the place formed by the roads traveled buckled and the approach of moving away the taxi with a dull moan. In fact each of the two taxi produces its MI, for which the two sounds vibrate more so the tone becomes higher, in an instability that is resolved if two cars to happen d'cross the street. What do you offer is a realistic simulation, from which they were removed, however, the long periods of inactivity.