Reference / wavetable terms
Wavetable glossary.
Definitions of the terms you encounter while designing, editing, and exporting wavetables.
Wavetable synthesis
Wavetable synthesis plays short, looping single-cycle waveforms from a table and sweeps across them to change timbre while pitch holds still.
Wavetable position
Wavetable position is the index into a wavetable's frames that selects which single-cycle waveform, or blend of adjacent waveforms, the oscillator is currently playing.
Single-cycle waveform
A single-cycle waveform is one complete period of a periodic signal, stored as a fixed number of samples and looped by an oscillator to produce a steady pitch.
Wavetable frame
A wavetable frame is one single-cycle waveform occupying one slot in a wavetable; the number of frames sets how much timbral motion the table can hold.
Wavetable frame size
Wavetable frame size is the number of samples in each single-cycle frame, held constant across the whole table.
Interpolation between frames
Interpolation between frames is how a wavetable oscillator blends its two neighboring frames when position lands between them, so timbre changes continuously instead of in audible steps.
2048 × 256 table
A 2048 × 256 wavetable (256 frames of 2048 samples each) is the de facto modern standard layout, popularized by Serum and adopted by many current wavetable synths.
256-sample table
A 256-sample wavetable has frames that are 256 samples long. Several Eurorack wavetable modules use this frame size.
8×8 wavetable bank
An 8×8 wavetable bank lays 64 wavetables out on a grid, so two control signals, one per axis, scan the whole bank instead of one table's frames.
Morphing vs. crossfading
Crossfading is an amplitude blend between two wavetable frames, while morphing is the broader goal it serves: moving between frames so the result reads as one continuously evolving timbre.
Spectral morphing
Spectral morphing transitions between wavetable frames by interpolating partial amplitudes and phases instead of blending waveform samples directly.
Harmonics
Harmonics are components of a periodic waveform at whole-number multiples of its fundamental frequency. The second harmonic is at twice that frequency and the third at three times it.
Partials
Partials are the individual sine-wave components of a sound's spectrum. They include harmonics and, in sounds that contain them, inharmonic components.
Formant
A formant is a resonant region in a spectrum that stays at roughly the same frequency as the played pitch changes. Formants help distinguish vowel sounds.
Phase
Phase is each partial's offset within the waveform's cycle, where in the loop every sine component starts, measured as an angle rather than a time.
Phase distortion
Phase distortion reshapes a waveform by varying the rate at which an oscillator reads it within each cycle.
FFT resynthesis
FFT resynthesis analyzes a waveform with a fast Fourier transform (the algorithm that reports one magnitude and phase per frequency slot), edits that spectrum, and rebuilds a waveform from it with the inverse transform.
Resynthesis
Resynthesis is analyzing an existing sound and rebuilding it as a wavetable, converting spans of the source into single-cycle frames rather than playing back samples.
Waveshaping
Waveshaping passes a signal through a transfer curve. It computes each output sample from an input sample to change the waveform's harmonic content.
Wavefolding
Wavefolding is a waveshaping technique that reflects a signal back on itself once it passes a threshold, multiplying harmonics without changing the fundamental.
Hard sync
Hard sync is an oscillator arrangement in which a master oscillator resets a second, detuned oscillator every time the master completes its own cycle, producing a biting, formant-rich tone.
Through-zero FM
Through-zero FM is frequency modulation in which the carrier's frequency is allowed to pass through zero and come out negative, continuing the phase in reverse rather than stopping.
Pulse-width modulation
Pulse-width modulation (PWM) varies a pulse wave's duty cycle. The duty cycle is the fraction of each cycle spent at its high level, and changing it changes the timbre.
Formula-generated wavetable
A formula-generated wavetable has frames computed from expressions evaluated per sample and per frame.
Aliasing
Aliasing is inharmonic distortion that appears when a digital signal contains frequencies above half the sample rate (Nyquist), which reflect back down into the audible range.
Band-limiting
Band-limiting restricts a waveform's harmonics to frequencies below the Nyquist limit, which is half the sample rate.
DC offset
DC offset is a nonzero average level in a waveform. The cycle sits above or below zero instead of being centered on it.
Wavetable bank
A wavetable bank is a grouped collection of wavetables that an instrument loads together and offers under a single browser or selector.
WAV file
A WAV file is the everyday audio container: a header describing the format, a block of sample data, and room for extra metadata chunks.
Packed wavetable WAV
A packed wavetable WAV is a single audio file that stacks every frame of a wavetable end to end, so a wavetable-capable synth can import the whole table from one file.
clm chunk
The 'clm ' chunk is optional metadata in some Serum-format wavetable WAV files; plain WAV exports may omit it.
srge chunk
The 'srge' chunk is Surge XT's own versioned metadata chunk inside WAV files, telling its importer the frame layout the same way Serum's 'clm ' chunk does.
wt file
A .wt file is Surge XT's native wavetable format: a short tagged header followed by the table's frames as raw samples, optionally trailed by metadata.
vitaltable file
A .vitaltable file is Vital's native wavetable format. It is a readable JSON document describing how the table was built instead of storing only rendered audio.
uhm format
A .uhm file is a u-he Hive wavetable script: a readable text file of commands and formulas that Hive evaluates step by step to build a wavetable.
Additive synthesis
Additive synthesis builds a sound by summing sine-wave partials. It sets each component's amplitude and, optionally, its phase.
Subtractive synthesis
Subtractive synthesis starts with a harmonically rich waveform and removes or reduces parts of its spectrum with filters.
Granular synthesis
Granular synthesis builds sound from many short grains. Each grain is a brief, windowed slice of an audio buffer played at a chosen time and pitch.
Wave sequencing
Wave sequencing plays a programmed series of waves within one note. The Korg Wavestation supports up to 255 steps with settings for duration, pitch, and crossfade.
PPG Wave
The PPG Wave is the synthesizer line that introduced commercial wavetable synthesis, built by Wolfgang Palm's Palm Products GmbH from 1981 to 1987.
Waldorf Microwave
The Waldorf Microwave (1989) is the rack synthesizer that carried PPG's wavetable lineage forward after PPG closed, pairing wavetable scanning with an analog filter.
Korg DW-8000
The Korg DW-8000 (1985) is a hybrid synthesizer with 16 stored digital waveforms and an analog filter. Its DWGS oscillators select a fixed waveform rather than scan a wavetable.
Ensoniq Transwave
A Transwave is Ensoniq's variant of wavetable scanning. Instruments such as the VFX, TS, and Fizmo sweep stored waves with programmable start, end, and loop points.
Adventure Kid Waveforms
Adventure Kid Waveforms (AKWF) is Kristoffer Ekstrand's free library of several thousand single-cycle WAV files for samplers and wavetable synthesizers.