Sound Design Workshop: Beyond Arpeggios, Part 2 - KeyboardMag

Sound Design Workshop: Beyond Arpeggios, Part 2

Part 2: Sound Effects
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Last month, we explored arpeggiators as tools for creating unusual waveforms and timbres. This month, we’ll look at ways to use them to generate sound effects that would be difficult to achieve using traditional MIDI sequencing techniques.

The key to this month’s tutorials is learning how to use three important features in modern arpeggiators—free-rate tempo settings, non-octave transposition steps, and single-iteration patterns. Ableton Live’s arpeggiator offers all three, so we will use it as a reference.

In Propellerhead Reason, you will find a Free setting on the tempo control of its arpeggiator. Other DAWs also support many of these features, though you may need to do a bit of exploring to locate the exact parameters on your preferred platform.

VINTAGE GAME EFFECTS AND CHIPTUNE SOUNDS

Replicating 8-bit video-game effects is remarkably easy when you incorporate an arpeggiator. The synthesis side is dead simple: Just use a single square wave, an open filter, and a gate envelope (sustain only). This was the most common tone source for classic arcade games, since a digital square wave is just a series of alternating 1s and 0s.

Fig. 1

Fig. 1

On the arpeggiator side, use a fast rate—either tempo-synced at 64th notes or free-running in the 10-30 millisecond range—and experiment with the interval and steps parameters (see Figure 1). The interval parameter determines the width of the arpeggio jump, whereas the steps parameter governs the number of jumps.

For example, if your interval is +12 semitones and you have a step value of 2, you’ll get a traditional two-octave arpeggio. With a square wave running at fast rates, this will instantly sound familiar. However, if your interval is +2 semitones and the step value is 8, playing a single note with an Up arpeggiation will produce a pattern that rises by whole-steps eight times, then repeats. Each permutation of step and interval values delivers a different vintage-game effect, so spend some time exploring different combinations.

GLISSANDOS, STRUMS, AND BELL TREES

The Repeat parameter is an often-overlooked feature that is essential for using arpeggiators to create glissandos and strummed effects. Most arpeggiators are used in Infinite mode, creating endless rhythmic cycles. Setting this parameter to a value of 1 results in a single cascade of notes that does not repeat.

In addition to steps and intervals, Live’s arpeggiator also lets you select specific key transpositions with major and minor options for each. If you start with a chime preset, you’ll evoke bell and mark-tree glissandos. With a guitar preset, the result will be authentic strums.

Fig. 2

Fig. 2

To start your experiments, set the arpeggio timing to 50 milliseconds, the interval to +7 semitones (a perfect fifth), and the steps value to 4 (see Figure 2). Then select a key and play a chord or any cluster of notes. With these settings, the results can be quite dramatic—and pretty.

If your preferred arpeggiator doesn’t directly support the interval settings described above, there’s a workaround that will approximate these techniques. Insert a MIDI processing device that generates specific chord voicings from a single note, then configure it according to the desired effect (strums, glissandos, chiptune steps).

Fig. 3

Fig. 3

For example, Apple Logic’s Chord Trigger lets you assign any configuration of notes to one or more keys, then transpose or alter that chord configuration as you play different notes (see Figure 3). From there, place the chord object before the arpeggiator in your chain. It’s not quite the same effect, but in a pinch, it may do the trick.