 Specialized accordion sound modules offer tens or even hundreds of different accordion sounds.Some Ketron and Orla accordion sound modules also have a programmable drum machine and music sequencer that can play backing tracks in a variety of musical styles.An accordionist with a digital accordion which has an internal sound module can plug the MIDI out into an external sound module to gain access to more sounds or features such as a sustain pedal or separate left hand and right hand outputs, if these are not available on their instrument.