Complex sentence: Controllers are devices that provides the human-playable interface and may or may not produce sounds of its own, or a sequencer, which is computer hardware or software designed to play electronic musical instruments.
Split into simpler sentences: Controllers are devices that provides the human-playable interface and may or may not produce sounds of its own. Another common way of controlling a sound module is through a sequencer, which is computer hardware or software designed to play electronic musical instruments.