In music production, a sequencer is a hardware or software device designed to record performance data and play it back in sequence, or in a specific order of events. Early sequencers were analog and programmed by setting a series of voltages (representing pitch) with potentiometers that triggered VCO’s. The playback involved having a clock step through or trigger each of these “events” in sequence. Modern sequencers have evolved well beyond that original concept and now have very sophisticated editing and performance features. Nowadays a large percentage of music composition and arrangement is done with sequencers and MIDI instruments. We also now have sequencers with digital audio recording and editing capabilities built in.