Roland mc 303 groovebox manual pdf The Roland MC-303 Groovebox is a self-contained, retro-styled sequencer and integrated sound module with some very high-tech features. This owner’s manual consists of the following 16 chapters and supplementary information. or an authorized Roland distributor, as listed on the "Information" page. On your choice of the Roland MC-307 Groove Box. Manual (P.133). of the groovebox. It features functions that.