Sound in UX design can be used in a variety of ways; to navigate the interaction, for branding, to set the ambience etc. The importance of sound for the user experience of a product is undeniable; however, this is not represented in the practices of UX designers. UX designers lack the tools and knowledge needed to integrate sound design into their prototyping activities. As a result, the sound is often considered last-moment, limiting the creative potential and added value of sound in the interaction. This report explores the possibilities of integrating sound design activities into the practices of UX designers. This is done through design research activities such as interviews, co-creation sessions, creating (interactive) prototypes and user testing. The aim of the project is to provide UX designers with prototyping tools for sound design. Common sound design tools are difficult to integrate in prototyping activities as UX designers often lack the skills and knowledge needed to operate these tools in a quick-paced and iterative way; which is needed in order to facilitate prototyping. Furthermore ways of bridging the semantic gap between the stakeholders is explored as well as the potential of tangible interfaces in making sound design more intuitive and engaging for UX designers. Finally, a concept is introduced: The Timbreworld, parts of which are embodied in an interactive prototype. The Timbreworld is a (tangible) interface for sonic sketching, it enables its users to create quick and iterative sound prototypes. The interactive prototype has been tested with participants and evaluated based on the design guidelines provided in the report