Sound Design: Saturation

Controlled distortion can be a sine wave’s best friend

Distortion and overdrive are normally considered the domain of guitarists (and 303 lovers), but in the context of sound design, they can be a powerful resource for transforming simple waveforms – especially sine and triangle shapes – into complex tone generators.

In fact, much of what we call the ‘West Coast’ sound is derived from Buchla’s wavefolding tools, which are quite similar to distortion circuits, with the added twist of inverting the tops of the waveform downward, creating what looks like ‘folding’, hence their name.

While single-oscillator sine and triangle waves are the optimal choices for saturation applications, digital synths have such precise tuning that you can achieve even more impressive effects by combining two or three sine wave oscillators at different harmonic tunings before sending them to the saturation processor. Octaves and fifths yield the cleanest results, while detuning one oscillator in a pair of sine waves can be useful for bell and mallet tones with unusual sidebands. Additive synthesis is another option for clean results, since harmonics are mathematically correlated.

Although many modern softsynths include polyphonic wavefolding and distortion as part of their oscillator and/or processing sections, it’s not as ubiquitous as you might assume. In this case, you can use a monophonic sine or triangle wave as the input to a distortion or saturation effect. iZotope’s iconic Trash 2 is a mainstay for many artists who rely on this approach for unusual sounds. Keep in mind that non-harmonic intervals can wreak havoc with drive-based waveshaping, which is why some rock guitarists stick with fifths for their riffing.

This month, we’ll look at two approaches for incorporating saturation and wavefolding into your design process, using Ableton Operator and Phase Plant.