Improved MIDI Message for Robotic Angklung Choir

Angklung is a unique musical instrument from South East Asia that should be played in a choir, because each angklung can only produce a single note. In a decent angklung composition, at least 3 angklungs should be played together to perform a sound harmony while certain parts of the song might demand up to 10 voices. Moreover, there are two different angklung playing techniques called kurulung (shaking) and centok (snapping). This paper presents the problems of conducting such of act by an angklung robot, then proposes some improvements to MIDI protocol to overcome the challenges.