Abstract: The invention herein concerns a system for permitting those with little or no musical training the ability to compose unique musical compositions from a variety of prerecorded loops. The loops can include sounds, musical phrases and the like and exist in various groupings designed to be compatible with one another in terms of key, beats per minute and musical style, such as, rock, blues or country. Where a loop is of a different grouping it can be easily and automatically modified in terms of pitch and tempo to be compatible with loops of another grouping.