Tabletop role-playing games are a collaborative narrative experience. Throughout gaming sessions, Ambient music and noises are frequently used to enrich and facilitate the narration. With AmbiDice we introduce a tangible interface and music generator specially devised for this application scenario. We detail the technical implementation of the device, the software architecture of the music system (AmbientMusicBox) and the scripting language to compose Ambient music and soundscapes. AmbiDice was presented to experienced players and gained positive feedback and constructive suggestions for further development.