Mixed music is music combining acoustic instruments and fixed-media electronics (e.g concrete sounds, sound-file playback etc) or more generally, music which combines acoustic-instrumental and electronic sounds sources (to the exclusion of electrically amplified instruments, such as the electric guitar and electronic instruments such as the theremin, electronic organs & keyboards, etc); mixed music is therefore a subcategory of electronic music. While this term could be applied to many genres, the term mixed music generally refers to contemporary classical music repertoire and is therefore distinct from live electronic music.