3.0 KiB
Wavetables
Any sample can be played as a wavetable. When you use the scan parameter, the sample automatically becomes a pitched oscillator that can morph between cycles.
What is a Wavetable?
A wavetable is a series of single-cycle waveforms stored end-to-end in an audio file. Each cycle is a complete waveform that starts and ends at zero crossing, allowing it to loop seamlessly at any pitch.
Sample: [cycle 0][cycle 1][cycle 2][cycle 3]
↑ ↑
scan 0 scan 1
The oscillator reads through one cycle at audio rate (determining pitch), while scan selects which cycle to play. Values between cycles crossfade smoothly, creating timbral morphing.
Basic Usage
Just add scan to any sample and it becomes a wavetable:
pad 0 scan . ( play pad as wavetable, first cycle )
pad 0.5 scan . ( blend to middle cycles )
pad 440 freq 0 scan . ( play at A4 )
Without scan, the sample plays normally. With scan, it becomes a looping wavetable oscillator.
Parameters
| Parameter | Range | Description |
|---|---|---|
scan |
0-1 | Position in wavetable (0 = first cycle, 1 = last) |
wtlen |
samples | Cycle length in samples (0 = entire sample) |
Cycle Length
The wtlen parameter tells the engine how many samples make up one cycle. This must match how the wavetable was created, otherwise you'll hear the wrong pitch or glitchy artifacts.
pad 0 scan 2048 wtlen . ( Serum-style 2048-sample cycles )
pad 0 scan 1024 wtlen . ( 1024-sample cycles )
Common cycle lengths are powers of two: 256, 512, 1024, 2048. Serum uses 2048 samples per cycle. The number of cycles in a wavetable is the total sample length divided by wtlen. If wtlen is 0 (default), the entire sample is treated as one cycle. The sample still loops as a pitched oscillator, but scan has no morphing effect since there's only one cycle.
Scanning
The scan parameter selects which cycle to play:
pad 0 scan . ( first cycle only )
pad 0.5 scan . ( blend between middle cycles )
pad 1 scan . ( last cycle only )
Scan Modulation
Use audio-rate modulation words to automate the scan position:
pad 0 1 2 lfo scan . ( sine LFO, full range, 2 Hz )
pad 0 0.5 1 tlfo scan . ( triangle LFO, half range, 1 Hz )
pad 0 1 0.5 jit scan . ( random scan every 0.5 steps )
Creating Wavetables
A proper wavetable file:
- Contains multiple single-cycle waveforms of identical length
- Each cycle starts and ends at zero crossing for seamless looping
- Uses power-of-two cycle lengths (256, 512, 1024, 2048)
- Has cycles that morph smoothly from one to the next
You can find wavetable packs online or create your own in tools like Serum, WaveEdit, or Audacity (using zero-crossing snap). Single-cycle waveforms also work. With wtlen set to 0, a single-cycle sample becomes a basic pitched oscillator.