|Abstract||The aim of this document is to discuss possible ways of describing some music constructs in a dual context. First, that of the current standard for multimedia content description MPEG-7. Second, that of a specific software application, the Sound Palette (a tool for content-based management, content edition and transformation of simple audio phrases). We discuss some MPEG-7 limitations regarding different musical layers melodic (present but underdeveloped), rhythmic (practically absent) and instrumental (present though using an exclusive procedure). Some proposals for overcoming them are presented in the context of our application.