Synthetic multi-string musical instruments have been developed for capturing and rendering musical performances on handheld or other portable devices in which a multi-touch sensitive display provides one of the input vectors for an expressive performance by a user or musician. Visual cues may be provided on the multi-touch sensitive display to guide the user in a performance based on a musical score. Alternatively, or in addition, uncued freestyle modes of operation may be provided. In either case, it is not the musical score that drives digital synthesis and audible rendering of the synthetic multi-string musical instrument. Rather, it is the stream of user gestures captured at least in part using the multi-touch sensitive display that drives the digital synthesis and audible rendering.