Wavetable Osc
A flexible wavetable oscillator with state-variable filter, ADSR, two LFOs and 32 onboard wavetables (64 waves each). Great for pads, leads and evolving textures.
Available on: Track 12 (Lead2) — default boot host. Selectable on Lead2 alongside other lead voices (TBDaits, Mono Synth). Built on: Custom CTAG wavetable voice using the Plaits wavetable oscillator helper, a CTAG ADSR, an LFO, and ~33 KiB of PSRAM-cached wavetable data per active bank.
Character
Two-dimensional wavetable scanning — pick a Bank (32 wavetables, each holding 64 waves) then sweep through Wave positions for evolving timbres. The ADSR + LFO can modulate wave position, oscillator FM, filter cutoff and amplitude — enough routing to build classic “moving pad” or “evolving bass” sounds wavetables are loved for.
A dedicated Env-GFX page shows the live ADSR shape as a graphic — knobs land directly on the curve so you can sculpt envelopes by eye.
Gotchas before you tweak:
- Bank-switch is heavy — the active bank is preprocessed into PSRAM (~33 KiB). Changing Bank during playback briefly mutes the voice while the new wavetable is staged. Prefer locking Bank per pattern.
- Sync is a toggle — affects LFO reset phase on note-on only.
Parameters
The default Wavetable Osc performance macro is organised as 5 semantic pages × 4 knobs = 20 params:
| Page | Knob 1 | Knob 2 | Knob 3 | Knob 4 |
|---|---|---|---|---|
| Voice | Bank | Wave | Tune | Gain |
| Filter | Type | Cutoff | Reso | EG Flt |
| Env* | Attack | Decay | Sustain | Release |
| EG Mod | EG Wav | EG FM | LFO Spd | Sync |
| LFO Mod | L2 Wav | L2 AM | L2 FM | L2 Flt |
* The Env page renders as a live ADSR graph — see Env-GFX page below.
Voice
| Parameter | What it does |
|---|---|
| Bank | Select wavetable (0–31). Each bank holds 64 waves. Bank label shows the wavetable name on the OLED. |
| Wave | Scan position within the current bank. Hi-res 14-bit for smooth wavetable sweeps. |
| Tune | Oscillator fine tuning, bipolar ±12 semitones. Centre = unity pitch. Hi-res. |
| Gain | Voice output gain, 0–100 % (linear). Hi-res. |
Filter
| Parameter | What it does |
|---|---|
| Type | Filter mode — Off (bypass), LP, BP, HP. Default LP. |
| Cutoff | Filter cutoff frequency, log curve. Hi-res 14-bit. |
| Reso | Filter resonance (0 → 20×). Hi-res. |
| EG Flt | Envelope → Cutoff modulation depth, bipolar ±1 — negative closes the filter on note-on, positive opens it. Hi-res. |
Env (ADSR)
A full attack / decay / sustain / release amplitude envelope shapes every note. The page renders as a live graph (see below) but the four parameters behave normally — P-Lock and automation work as on any other parameter page.
| Parameter | What it does |
|---|---|
| Attack | 0.5 ms – 5 s exponential, hi-res. |
| Decay | 0 – 10 s exponential, hi-res. |
| Sustain | Sustain level 0–100 %, hi-res. |
| Release | 0 – 10 s exponential, hi-res. |
EG Mod
Envelope → destinations + main LFO speed/sync controls.
| Parameter | What it does |
|---|---|
| EG Wav | Envelope → Wave position, bipolar ±1. Negative swings the scan backward, positive forward. |
| EG FM | Envelope → Oscillator FM, bipolar ±12 semitones. |
| LFO Spd | LFO frequency in Hz, log curve, hi-res. Readout shows current Hz on the OLED. |
| Sync | OFF / ON — on note-on, reset LFO phase to 0 for rhythmic patches. |
LFO Mod
LFO → destinations. All unipolar 0–100 %.
| Parameter | What it does |
|---|---|
| L2 Wav | LFO → Wave position scan depth. |
| L2 AM | LFO → Amplitude (tremolo). |
| L2 FM | LFO → Oscillator FM depth. |
| L2 Flt | LFO → Cutoff depth. |
Recipes:
- Evolving pad: long Attack + long Release + slow LFO Spd + modest L2 Wav for wavetable drift.
- Plucky wavetable lead: short Attack + short Decay + Sustain
0+ strongEG Wavfor a swept transient on each note.- FM bass: short envelope +
EG FMcranked (bipolar — try positive for up-sweep, negative for down-sweep).
Env-GFX page
The Env page replaces the usual 4-column layout with a live ADSR graph drawn from the four envelope knobs:
- Linear curve segments connect the breakpoints (start → attack peak → decay end → sustain plateau → release end).
- Outlined breakpoint dots mark the A/D/S/R transitions.
- Dashed vertical gutters drop from each breakpoint so the time axis stays legible.
- Knob labels (
A/D/S/R) and values stay in fixed bottom positions; only the curve shape moves with the knobs. - P-Lock, Automation and MIDI-mapped indicators render as small overlays under the value, exactly as on the per-cell pages.
P-Lock, Automation and held-step parameter editing all work normally on this page — the graph is purely a visualisation; the underlying knobs are the same Attack / Decay / Sustain / Release params.
Factory presets
| Preset | Character |
|---|---|
Default | Plucky default — short A, medium D, Sustain 0, medium R, LP filter at moderate cutoff with a hint of resonance. Tune by ear from here. |
See also
- TBDaits — 24-engine macro voice on the same track (Lead2).
- Mono Synth — Braids macro-oscillator alternative on Lead.
- PolyPad — 24-voice polyphonic pad companion.
Origin & credits
Custom CTAG wavetable voice by Robert Manzke (GPL 3.0). Built on Mutable Instruments Plaits wavetable oscillator helpers (MIT), with a CTAG ADSR + state-variable filter and 32 onboard wavetables.
- DSP sources:
plaits/dsp/oscillator/wavetable_oscillator.h,helpers/ctagSampleRom.hpp,helpers/ctagADSREnv.hpp - TBD-16 wrapper:
rack/RackWTOsc.hpp/.cpp - Related reading: CTAG TBD plugins