Making The Most Of Arpeggiators

If, like Erasure, you're all fingers and thumbs, an arpeggiator can make inspirational note sequences a cinch. For this versatile synth function, however, that's only the beginning. Paul Ward blisses out on glissandos...

Arpeggiators have experienced something of a revival over the last couple of years. I was pleasantly surprised to find one on Quasimidi's Quasar, Technox and now Raven synths when I've reviewed them for SOS, and some physical modelling synths have taken the arpeggiator on board too, such as the Korg Prophecy and Clavia Nord Lead. With this in mind, the time would seem right to have a look at the features and possible uses of a typical arpeggiator.

'Arpeggiation' is basically the playing of chord patterns by sounding each note in a sequence, rather than simultaneously. Although this can obviously be achieved by recording the notes in step‑time into a sequencer, or by dextrous real‑time playing, the term 'arpeggiator' is usually applied to a device which does it automatically.

The arpeggiator as we know it had its roots in the early step‑time sequencers found on giant modular synth systems of yesteryear. These sequencers managed eight or 16 notes at most, and were programmed by tuning a row of control knobs — one for each note of the sequence. Once programmed, the voltages set by each control knob would be played back in sequence (hence the origin of the term 'sequencer') and sent to the control voltage input of an oscillator to provide pitch information. Note lengths were identical for each step of a sequence, although some models allowed steps to be set as 'rests', to provide some variation in rhythm.

Since a step‑time sequencer was difficult to re‑program during a performance, they were usually confined to providing simple backing patterns. Sequences could often be transposed by pressing a keyboard note, so a limited amount of harmonic progression was possible. With the advent of the arpeggiator, however, the problems of real‑time control were largely solved — albeit with a modicum of compromise over the actual pattern of notes produced.

Getting Started

Using an arpeggiator is usually very easy: hit the arpeggiator's 'on' button, hold down a few notes and adjust speed to taste. When confronted with a synth with an on‑board arpeggiator, this would be considered the bare minimum of controls. Most machines take things a little further, however, with any or all of the following features:

A 'Direction' control allows the note order of playback to be defined — usually a choice of up (in the case of a C triad, this would play C, E, G, C, E, G repeatedly), down (G, E, C, G, E, C, G...), up/down (C, E, G, E, C, E, G, E...) or random. A 'Hold' button allows note patterns to be triggered which keep playing when the keys are released — pressing a new group of keys often cancels the first and begins a new arpeggiation pattern. A 'Range' control sets the group of notes to be replayed over one, two or three octaves (the equivalent of holding down the corresponding keys over one, two or three octaves — if you have enough hands free!). Rather more rare is the ability to change the gate time of the triggered notes, to enable staccato or legato effects.

One feature which I have only ever come across on Sequential's excellent Pro One monosynth is in its 'latched' mode. 'Latch' can simply be thought of as 'hold', but the Pro One has one extra trick up its sleeve. Whilst latched, pressing keys on the keyboard will cause those notes to be added to the arpeggio for as long as the extra notes are held down. This feature has never found much musical use in my studio, but I'm always keen to learn, if someone out there cares to enlighten me!

The number of notes held and their playback direction will define the time signature of the arpeggio. In our C triad example above, notice that we have three repeating notes with the up or down direction, but four when using the up/down option. That's not to say that you should slavishly follow the rules: I've often used 7/4 arpeggios over 4/4 rhythms to add some degree of movement and 'creative entropy' to the proceedings!

Generally speaking, short percussive patches (fast attack, short to medium decay, no sustain, short to medium release) make for good arpeggio sounds that will help carry the pulse of a song. On the other hand, turning up the attack time will help to 'soften' the notes and make them blur into the mix — without the need to turn the instrument down and lose the effect entirely. If your arpeggiator provides an adjustable gate time parameter, this will define the period during which the sound will pass though its attack, decay and sustain phases. Very short gate times allow the creation of faster, harp‑like glissandos, whilst longer gate times will eventually lead to notes overlapping each other.

New Dimensions

One of the most satisfying uses I have made of an arpeggiator is in conjunction with a reverb. Start with a fairly simple sound on the arpeggiating synth: something akin to a piano would be fine, although the details are not critical. Set the reverb for a long decay time (somewhere around 10 seconds works nicely as a starting point) and feed the arpeggiated notes in. Make sure you are only hearing the reverberated sound (either by turning the reverb mix to reverb only, or switching the original sound out of the main mix on your desk). Gradually increase the attack time on the synth. At some point, the reverb signal will begin to 'smooth' out, as it is fed by the sound with gentle attack and release characteristics. The reverb will now appear to be 'playing' a chord! Now, change the arpeggiated chord. As the reverb of the old notes dies away, it should progressively be replaced by the reverb from the new notes. You will hear an ethereal, fluid crossfade from one chord to the next. Beware — this way lies new age! At the first sign of nausea, set off an acidic Roland TB303 sequence and have a cup of hot, sweet tea...

Delays also work well with arpeggiated material. Try to go for long‑ish delay times that fall between the original notes. Slight changes in chord shape/inversion, arpeggiation direction and numbers of notes make a vast difference to the results. The best way is to keep experimenting until you hit a 'sweet spot' — once achieved, there's very little that you can do to actually make it sound bad!

Arpeggiators can also be put to use for other than playing notes. I use the following method with a Sequential Pro One, though I'm sure other synths will be capable of similar results — provided they have an audio input, of course. What I do is turn down the output from the oscillators, and feed in an external sound source; maybe a rhythm guitar track. The control voltage from the arpeggiator I send to the filter cut‑off. With the guitar track playing and the arpeggiator in action, the subtle changes in tone can add interest to an otherwise ordinary backing part. Apply a little resonance if you want things to get less subtle, and make wider spacings between the arpeggiated notes. If you can synchronise the arpeggiator to the tape tracks, so much the better.

Your Flexible Friend

The real beauty of arpeggiators is that they give a form of 'sequencing' without requiring you to decide what the sequence will be beforehand. Jamming along to an arpeggiator can be an exhilarating experience, since you have the freedom to change chords or time signature at will. When all else fails, just hit a pair of bass notes one octave apart, for an instant late‑70s disco pulse — until everyone manages to catch back up!

So, next time you find yourself stuck for inspiration, just hit that button marked 'arpeggiator', jab a few chords and see what happens. After all, some '80s bands made a career out of it!