Wavetable synthesis gives a synth access to far more than the four classic waveforms. A wavetable is a collection of single-cycle waveforms arranged in order; the synth can play any one of them, or move smoothly through them while a note plays. That movement - timbre changing continuously over time - is the signature of wavetable synthesis.
How it works
- A wavetable holds a series of waveforms - often 256 of them - in sequence.
- The wavetable position (or "index") chooses which waveform is playing.
- Modulating the position with an envelope or LFO scans through the table, morphing the sound as it goes.
Wavetable synthesis was pioneered in the late 1970s and 80s by PPG and Waldorf. Today, software wavetable synths - Native Instruments' Massive X, Xfer's Serum, Ableton's Wavetable, the free Vital and many more - are central to modern electronic music, especially bass music, EDM and pop.
Wave position
Some tables morph gradually - a sine slowly becoming a sawtooth. Others jump between very different shapes. Moving the position:
- Slowly with an LFO - evolving pads and drones.
- Quickly with an envelope - a dramatic timbre change at the start of each note.
- Rhythmically with a tempo-synced LFO - talking, growling basses.
- With the mod wheel or velocity - expressive control while playing.
Warp modes
Many wavetable synths can distort the waveform further with warp modes:
- Sync - mimics oscillator hard sync, sweeping through harmonics.
- Bend and squeeze - shift the shape of the waveform.
- Phase distortion - Casio-style timbre changes.
- FM from another oscillator - adds FM complexity.
- Mirror, quantise, remap - stranger, more digital colours.
Building your own wavetables
Most wavetable synths can import audio and turn it into a wavetable - a vocal, a field recording, a guitar chord, a drum loop. The synth slices the audio into single cycles and arranges them as a table. Scanning through it recreates the changing timbre of the original audio as a playable instrument. Some synths also let you draw waveforms or generate them from formulas.
Wavetable plus subtractive
Wavetable oscillators usually feed a conventional filter, amplifier and effects section. The usual subtractive techniques apply - but because the oscillator itself can change timbre, you often need less filtering. The classic modern bass patch combines wavetable position movement, a filter, distortion and a tempo-synced LFO.
Unison and width
Like subtractive synths, wavetable synths offer unison - many detuned voices spread across the stereo field. Huge for leads and pads; usually kept narrow or mono for basses, so the low end stays solid.
Do this now
- In a wavetable synth, load a table and move the position by hand while holding a note. Listen to the timbre change.
- Assign a slow LFO to the position for an evolving pad.
- Assign a tempo-synced LFO at 1/8 note to position and filter together for a moving bass.
- Import a short vocal phrase as a wavetable and play it as an instrument.