This paper explores participatory and socially engaged practices in ubiquitous music (ubimus). We discuss recent advances that target timbre as their focus while incorporating semantic strategies for knowledge transfer among participants. Creative Semantic Anchoring (ASC from the original in Portuguese) is a creative-action metaphor that shows promising preliminary results in collaborative asynchronous activities. Given its grounding in local resources and its support for explicit knowledge, ASC features a good potential to boost socially distributed knowledge. We discuss three strategies that consolidate and expand this approach within ubiquitous music and propose the label Radical ASC. We investigate the implications of this framework through the analysis of two artistic projects: Atravessamentos and Ntrallazzu.