What is wavetable synthesis?
Wavetable synthesis builds sound from a table of single-cycle waveforms. Moving through the table changes the waveform while a note plays, so a sound’s harmonic content can evolve continuously, from soft and pure to bright and complex.
How it works
A single-cycle waveform is one period of a wave, repeated at the pitch you play to make a steady tone. A wavetable holds a series of them, called frames, arranged so that neighbouring frames are related. A position control chooses which frame plays, and the synthesizer blends smoothly between frames as the position moves.
Each frame has a harmonic recipe of its own, so sweeping the position reshapes the whole spectrum in ways a filter alone can’t reach. Moving the position with an envelope or a slow wave gives a sound that keeps changing as it plays.
Wavetable instruments add ways to bend the waveform further. Warping squeezes or stretches parts of the cycle, folding reflects the wave back on itself to add harmonics, and frames can be drawn by hand, generated from mathematical functions or captured from recorded sound. The result then usually passes through filters, envelopes and modulation, as in subtractive synthesis.
What it sounds like
Wavetable synthesis excels at sounds that move. Evolving pads, basses whose character changes with every note, glassy digital bells and textures that shift from smooth to aggressive all come naturally to it, and it covers classic analog-style tones too.
Key terms
- Single-cycle waveform
- One period of a wave, looped at the played pitch to produce a steady tone.
- Wavetable
- An ordered set of single-cycle waveforms, called frames, that a synthesizer can move through.
- Wavetable position
- The control that chooses which frame plays, or where between two frames.
- Interpolation
- Blending between neighbouring frames, so the position can move smoothly.
- Warp
- Reshaping a waveform’s cycle, for example by bending or squeezing it, to change its harmonics.
- Wave folding
- Reflecting a waveform back on itself when it passes a limit, which adds bright harmonics.
In The Spectral Star
The Spectral Star is Xionia Audio’s wavetable synthesizer. It’s designed to turn waveforms into living landscapes of harmonic possibility, so you can sculpt them, transform their spectrum and set every detail in motion, and it takes in recorded sound as waveform material. Its waveform position, harmonic structure, warp, fold and filter can each have a Motion Wave of its own.