AN INTRODUCTION TO ARPEGGIATORS
If you have ever taken any sort of music class involving band instruments (woodwind, brass, etc.), then you have spent a great deal of time just playing scales and learning the structure of the instrument. It can be pretty boring going up and down the same scales all day long – but it teaches the musician how to get range out of their instrument. You might have also worked on arpeggios which behave like an octave, but instead of taking half or whole steps you are taking multiple steps on every note. Early synthesizers took advantage of this mathematical frequency trick which could be used to create modulating sounds off of only one note.
Every “arp” instrument has some form of control over the speed, the note, and the range of that note. It allows you to create bars of music without actually having to create them one at a time or by layering – the instrument simply runs up and down a certified path of notes that are guaranteed to sound correct. Uses for the arp are still abundant – but modern DAWs usually eliminate the need to have a hardware console that is capable of this, and the same effect can just as easily be manipulated using software alone.