A “Concatenative Synthesizer” applies concatenative synthesis to create a musical output from a database of musical notes and an input musical score (such as a MIDI score or other computer readable musical score format). In various embodiments, the musical output is either a music score, or an analog or digital audio file. This musical output is constructed by evaluating the database of musical notes to identify sets of candidate notes for each note of the input musical score. An “optimal path” through candidate notes is identified by minimizing an overall cost function through the candidate notes relative to the input musical score. The musical output is then constructed by concatenating the selected candidate notes. In further embodiments, the database of musical notes is generated from any desired musical genre, performer, performance, or instrument. Furthermore, notes in the database may be modified to better fit notes of the input musical score.