Arpeggiators have been a staple of electronic music for decades; one of the very first arpeggiators (perhaps the very first?) appeared on the Elgam Carousel, an Italian auto-accompaniment keyboard for organ players. Because the term "arpeggiator" hadn't been coined yet, it was called "Crazy Hands"!
Arpeggiators turn chords (groups of held keys) into patterns of held notes, played in rhythm. This can produce a variety of fascinating and exciting melodic effects. With the advent of complex digital control, the primitive arpeggiators of the mid-1970s have evolved into an entire subculture of arpeggiator designs, each with its own unique functions and options.
ODC 2800's arpeggiator features a good range of musical options, managed via the following controls:
Speed- Sets the pattern speed playback speed from 0.25 to 30 Hz. The LED in the top left corner of the Arpeggiator panel flashes to indicate the current speed (and stops flashing when the Arpeggiator is turned off).
Sync- Engaging the Sync control locks arpeggio timing to master tempo. When engaged, the Speed slider changes from a rate in Hz to note values ranging from 1/64th note triplet to 8 beats. When using the ODC 2800 standalone version, the Arpeggiator uses the Tempo in the top toolbar. When it's used as a plug-in inside a DAW, it syncs to the DAW tempo.
Swing- This slider lets you put a swinging groove into your arpeggiations. When it's set to 0.0%, then the arpeggio plays back in a straight timing. As you turn up the Swing, every other note is delayed by a small amount, creating the swing effect. Try it at 67% for a very familiar triplet feel.
Chance- Sets the probability of a note sounding on a given step. The default is 100%, i.e. every note is always played. The Chance slider can be turned down to 30%, meaning that each note in the arpeggio only has a 30% chance of playing. This lets you create random rests, blank sections, and syncopations, depending on the Chance setting.
Feel- This slider adds randomness to the timing of the arpeggio. You can choose to push notes slightly ahead of the beat, or pull notes slightly behind the beat. It defaults to 0, but can be moved to ±100% push or pull. If you're recording the arpeggios into a DAW, you can automate the Feel parameter to gently alter the push/pull character of the arpeggio, "humanizing" it a bit.
Hold- Press this button to keep the arpeggio going even when all keys are released. You can clear the current arpeggiation and replace it with a new one simply by releasing all keys, then playing a new chord. The arpeggiation will continue until Hold is turned off. This function, often called Latch, is a useful one to assign to a pedal or button for live use.
Mode switch-
OFF- Arpeggiator is disabled. The LED at top left flashes at the current tempo when the Arpeggiator is enabled.
ARP- Plays notes according to the Direction control setting.
Up: Held notes sound from lowest to highest.
Up/Down: Held notes sound from lowest to highest and back down to lowest.
Down/Up: Held notes sound from highest to lowest and back up to highest.
Down: Held notes sound from highest to lowest.
ORD- Plays the notes in the order they are pressed, dependent on current Direction setting.
Up: Notes sound in original order played.
Up/Down: Notes sound in original order played, followed by reverse order played.
Down/Up: Notes sound in reverse order played, followed by original order played.
Down: Notes sound in the reverse order they were played.
RND- Plays held notes in random order.
Direction- The Direction control functionality varies a bit depending on the current position of the Mode switch as follows:
In ARP Mode: Selects Up, Up/Down, Down/Up, or Down note playback.
In ORD Mode: See Order section above.
In RND Mode: Direction is grayed out and doesn't influence the arpeggiation.
Range- Selects how many octaves the pattern will play before repeating, from 1 (just the notes held) to 4 (the notes held, but repeated over three octaves above the held notes).
Note that the difference between Up/Down and Down/Up is much easier to hear when the Range is set to 3 or 4. Play a single note and hear where the arpeggio starts.