Systems and methods for composing music

Generating a musical composition from one or more portions of one or more performances of one or more musical compositions included in a database is disclosed. The method and system include selecting a portion of a pre-recorded composition based on a degree of similarity with the component of the composition that is input; portions that are musically similar but not musically the same as the component may be selected for addition to the composition. The degree of similarity may be based on a ChordScore and/or a ScaleScore of the retrieved portion of the pre-recorded compositions. A ChordScore is generated by comparing chord tones of one or more chords in the pre-recorded portion with chord tones of the input component. A ScaleScore is generated by comparing tones of one or more notes in the pre-recorded portion with tones in a harmonic scale associated with the input component's chords.