Editing a Wavetable
Frame order, interpolation and warp decide where a wavetable can travel; fix the endpoints before touching modulation.
Related
Scan a stock table at random and the timbre merely brightens and darkens; reach the end and you cannot say where you went. Editing a wavetable is really three decisions: which frames go in, what order they sit in, and what pushes the position.
Where frames come from
A frame can be drawn as a stack of harmonics, extracted as a single cycle from a recording, or resynthesised from a spectrum. Drawing suits clear endpoints; extraction keeps the detail of a real instrument but needs DC and noise removed. Normalise every frame to the same peak, or scanning turns into a volume ride. Eight to sixteen frames carry a continuous morph comfortably.
Scanning and warping are different jobs
| Control | What it acts on | What you hear | Typical use | Setting to watch |
|---|---|---|---|---|
| Scan position | Which frame plays | Dark to bright | Breathing pads | Sync to tempo |
| Scan rate | How fast it moves | Slow breath, fast sway | Rhythmic timbres | Share with the LFO |
| Warp | Shape inside one frame | Same frame, wider or narrower | Fine sustain shaping | Level changes |
| Phase alignment | Frame to frame | Less cancellation, fewer clicks | Harmonic tables | Common start phase |
A working method for one table
Set the endpoints first: a soft frame close to a sine, and a bright frame rich in harmonics. Fill the middle by ear rather than by arithmetic, adding frames wherever the change happens too fast. Check band-limiting frame by frame, playing up to the top of the range for aliasing hiss. Save the table with a name and a version, plus a fixed-pitch audio example.
Where it breaks
If frames disagree in phase, scanning cancels and the level jumps; if frames disagree in level, the scan sounds like tremolo; an unlimited table aliases in the high register; an envelope and an LFO both driving position fight each other and pull the timbre back halfway. Treating a wavetable like a sample also fails: a single-cycle table has a fixed length, and stretching it does not produce a longer note.
Listen in the library
All tracks from midicn-lib — inline badge is the license tier (C1 commercial / C2 non-commercial / C3 study only).
Along the same line
Sources
- Curtis Roads, The Computer Music Tutorial — 波表合成与插值
- Udo Zölzer，DAFX — Digital Audio Effects — 波表振荡器与限带
- Xfer Records，Serum 用户指南（厂商文档）— 波表编辑与变形模式