Urban sound is an ephemeral, immaterial and spatial aspect that usually does not receive the attention it deserves in urban planning. The listening object Sonic Aggregator changes this in two ways. On the one hand, the object is a visible “gathering place” for urban sound; on the other hand, the object enables the participation of the communities involved and offers a place in the urban space that is accessible to all. The listening object enables participation in an accessible and playful way and creates the conditions to critically examine listening experiences in urban space in a collaborative and participatory work process.