This paper presents a brief survey of currently ongoing research at DIST – InfoMus Lab on multimodal interfaces with a particular focus on Tangible Acoustic Interfaces (TAIs). A relevant aspect of our research is the multimodal analysis of the high-level expressive, emotional information, the involved non-verbal communication mechanisms, the role of such information and mechanisms in the design and development of expressive multimodal interactive systems based on TAIs. Research is carried out in the framework of the EU-IST project TAI-CHI (Tangible Acoustic Interfaces for Computer-Human Interaction), funded by the European Commission in the Sixth Framework Program. The paper provides a summary of the work performed in the project, including examples of ongoing experiments and prototypes developed with the new EyesWeb 4 open platform for multimodal processing (www.eyesweb.org).