How To: Chaos Rules

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Among the main characteristics of true analog instruments are the subtle idiosyncrasies that occur at the circuit level. While many modern softsynths attempt to re-create waveforms and filter curves accurately, there is a certain richness that comes with the variations that occur in real-world instruments. Even Dave Smith Instruments includes a “slop” parameter for the Prophet 08’s DCOs to re-create these artifacts.

This month, we’ll look at ways to use common tools, such as noise modulation and high-speed LFOs, to add low-level indeterminacy to your oscillators and filters.

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With Xfer Records Serum, you can mimic the subtle inconsistencies of analog circuitry using the soft-synth’s dual chaos generators, which blur the line between sample-and-hold and noise. The result is the ability to add complex, pseudo-randomization to almost any parameter.

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Available on classic analog instruments such as the Roland SH-101, as well as contemporary softsynths like Ableton Operator, the noise waveform on an LFO is a fantastic way to add gritty dirt to filter modulation, with or without resonance. Operator, in particular, includes noise as an LFO option and offers the added flexibility of choosing between low and high frequencies to create a wider range of textures.

The end result is similar to distortion, but with a nastier, animated quality. This technique is fantastic for designing industrial and techno leads and effects. Once you’ve routed the LFO to your filter, experiment with different frequency rates (if possible) but keep it subtle. A little goes a long way.

Moreover, applying a tiny bit of noise modulation to a single oscillator in an oscillator pair will add a chaotic, detuned character that’s quite similar to the supersaw waveform. The secret is to experiment with both high- and low-frequency noise rates, which Operator provides. Lower rates are ideal for the supersaw effect, while faster rates infuse a noise-like character on the oscillator pitch.

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Rather than offering noise as an LFO waveform option, Reason’s Subtractor provides two kinds of random waveforms, which behave similarly to noise when their rate is set to maximum. Using the technique described above, you can also create a supersaw effect by using a very fast, random LFO on one oscillator. Alternately, you can re-create analog drift by using a small amount of the second random waveform (which is smoother) at a much slower rate. You’ll achieve more “wobbly” effects by using a low-to-medium rate.

Another trick is to route Subtractor’s LFO to the cutoff of Filter 1. Using a high-speed random LFO, you can approximate the same “noise distortion” trick that’s available in Operator. On the other hand, adding just a touch of the modulation results in bit of simulated overdrive.


The random waveform of the OB-6’s LFO switches to noise mode when its rate is set to maximum. Consequently, the tricks outlined above can also be applied to this analog poly powerhouse.

To hear audio examples of each of these techniques, go to