Street art opens a new, broad research field in the context of urban communication and sound aesthetics in public space. The primary focus of this article is the relevance and effects of using sound technologies and audio devices to shape urban landscape and soundscape. This paper examines the process of developing an alternative type of street art that uses sound as its medium. It represents multiple audio device prototypes, which encourage new chances for street artists and activists to contribute their messages and signs in public spaces. Furthermore, it documents different approaches to establishing this alternative urban practice within the street art and new media art field. The findings also expose a research space for sound and technical interventions in the context of street art.