In this paper, we describe our work in progress on the reasoning module of ec(h)o, an augmented audio-reality interface for museum visitors utilizing spatialized soundscapes and a semantic web approach to information. We used ontologies to describe the semantics of sound objects and represent user model. A rulebased system for selecting sound object uses semantic description of objects, visitor's interaction history and heuristics for continuity of the dialogue between user and the system. Categories and Subject Descriptors C.3 [SPECIAL-PURPOSE AND APPLICATION-BASED SYSTEMS] Real-time and embedded systems General Terms Algorithms, Design, Experimentation, Human Factors Keywords Augmented-audio reality, ontologies, inference rules, user model