Some embodiments provide a music editing application that enables a user to compose and edit note characteristics, e.g., via a touch-sensitive display. The GUI can display a portion of a music track including note events. In response to receiving a user selection of a note event and a user indication for editing a note event, the GUI can display a menu providing a list of characteristics. The characteristics can include an option for associating at least one of several virtual instruments or one of several articulations with the note event. Upon receiving a user input indicating a characteristic, the matrix editor can associate the note event with the characteristic based on the user input. The music editing application can allow the user to edit additional note characteristics (e.g., an instrument, an articulation) because of the extended capacity for data associated with each note event.