The arpeggiators in Supernova can be synchronized to an incoming midi clock signal sent from a sequencer. To accomplish this, set the clock source found in the global menu to EXT (external). Ensure that midi clock is being transmitted from your sequencer into the correct midi port for the Supernova. The sequencer must then be put into either play or record mode as the Supernova needs a song start message for the arpeggiator to run. If the arpeggiator still does not run, double-check that midi clock is being transmitted from the sequencer NOT Midi Timecode (MTC). The Supernova cannot respond to MTC.