Abstract. The purpose of this paper is the exploration of the possibilities that Tangible User Interface (TUI) may offer in the area of sound synthesis, by reconfiguring the functionality of the existing TUI tabletop musical instrument called "Reactable" and redesigning most features, adjusting it to a synthesizers needs. For this research we analyzed sound properties, physics and formation, as well as how human used these features to synthesize sound. Afterwards we present the properties and advantages of TUI technology, and its use in sound and music, distinguishing Reactable, for being the most even musical instrument using TUI. As an outcome we develop and present an initial prototype modular synthesizer, called Spyractable. Finally, we subject Spyractable to users' evaluation tests and we present the outcomes, making suggestions for further investigation and design guidelines.