An arpeggiator is a device that splits the notes from a held keyboard chord into individual steps and cycles through them, in user-defined or random directions. The term originates with the arpeggio, which is a name for the same thing, played on a traditional instrument such as a piano or guitar. This principle is very effective, and was a key part of 80s synth performance, as the originators of synth pop used the arpeggiator presets that were built into their keyboards, or available through hardware sequencers – an arpeggiated pattern makes instant magic for monophonic synths. An arpeggiated synth with a TR-808 together become an irresistible hypnotic melodic machine, reaching peak 1980s! Many modern synth plugins include arpeggiators – like LFOs, they’re all over the place, which is just how we like it. In our world of software, things get even more interesting when we use these arpeggiators alongside other MIDI effects – ultimately we can create mobile and evolving musical patterns even if we’re indulging in one-finger keyboard playing… and that’s before we throw in any automation possibilities! In this short walkthrough we’ll use Apple’s Logic Pro X Arpeggiator and Drum Machine Designer presets to get some arpeggiator action.