Arpeggiator

Putting on our music theory hat for a second, an arpeggio is a type of “broken chord” where the notes are played individually rather than all at once. An arpeggiator – usually built into a keyboard, or a device inserted between your keyboard and sound module – makes it easier for you to play arpeggios: You just hold down the notes of the chord, and it automatically plays the notes one at a time, over and over again, like a step sequencer you can program on the fly just by holding down a chord. Good arpeggiators have options for different patterns (up, down, back and forth, random, etc.), and even a latch or hold where it will keep doing this even after you’ve released the keys.