The concept of Interaction Locus (IL) has been introduced to help the users to orient, navigate, and identify relevant interaction areas in 3D Virtual Environments (VE). The IL is a multimodal concept: it adds to the 3D visual scene parallel information channels that are perceived by other senses. In particular, the IL emphasizes the role of music as a navigation aid in a VE. The paper reports two experimental evaluations of the audio component of the IL, as implemented in the web site of a famous Italian Museum. The experiments investigated the different roles (functional or aesthetic) that a music component may play in VE navigation and content fruition. Results suggest that music plays an aesthetic role that the users appreciate very much. It can also plays a functional role, helping users to recognise scenes in a VE, provided that the users are informed in advance of the semantic linkage between music and virtual space.