Know Sound Design: The Friendly Sine Wave - KeyboardMag

Know Sound Design: The Friendly Sine Wave

Fundamental programming concepts
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With modern synths offering every imaginable waveform, it is easy to overlook the fact that even the most complex harmonic structures are still based on that essential building block of sound, the sine wave. While additive and frequency modulation (FM) are the most common sine-based approaches to synthesis, there is still a lot you can do with sine waves in a traditional two-oscillator subtractive synth.

With that in mind, this month we will take a look at three simple techniques that rely on sine waves to generate familiar and useful textures, using Propellerhead Reason’s handy Subtractor softsynth as the basis for these tutorials.

Subs and Fundamentals. While a single sine wave with no filtering is a classic way to create trap and hip-hop basses, blending low sine waves into multi-oscillator patches is a fantastic way to add low-end bombast with much more precise control than EQ provides. For example, create a simple two-oscillator patch, with one oscillator set to a sawtooth wave and the second oscillator set to a sine at either the same octave to emphasize the fundamental or an octave lower for bass enhancement. By adjusting the mix of the two oscillators, you can keep the fizzy highs of the sawtooth while adding warmth or bass with the sine.

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Faux B-3. With just two sine waves, you can create a serviceable jazz B-3 patch that sits quite well in a mix thanks to the sine wave’s lack of complexity. For the first oscillator, leave its octave setting at the default. Then tune the second sine wave an octave and a fifth—7 semitones—higher and make sure filtering is off (or the lowpass cutoff is at maximum). This will generate the pronounced third harmonic that is a hallmark of many B-3 drawbar settings. Be sure to set your amp envelope to a gate structure with instant attack, maximum sustain and immediate release.

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Bells. You can also use a pair of sine waves to create bell and chime textures, even without resorting to FM synthesis. First, create a bell-like envelope with instant attack, medium decay, no sustain and a longish release. From there, leave the first sine wave at its default octave, then tune the second sine wave to any random frequency at least two octaves higher. For example, you could set it to two octaves, plus a tritone (6 semitones) and +25 cents. In this case, the second oscillator generates a tone that’s not harmonically related to the fundamental, simulating the sound of certain metallic objects. Pro Tip: If you give your amp envelope a short decay and release, you can emulate mallet instruments too.

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