Every moment, the hearing system provides us with clues about the perception of our surroundings. We are able to roughly determine directions and distances of sounds in everyday life. However, to protect us from acoustic overstimulation, this ability remains relatively passive. The project "Hearo" includes a set of tools with which our acoustic perception of space can be actively explored. The toolbox is mobile and allows an experimental approach at various locations. During the playful usage, the user encounters repeatedly unexpected situations.