# DUSK DUSK is DUET's wavetable synth: a K## patch plays a sample of the song as a **wavetable** — a row of equal single-cycle frames — and morphs through them, with a SID-style envelope and a filter in software. It lives in a duet: an armed DUSK slot is a column on the grid, a strip on the mixer, and a K## list on the instruments page. Words are the [glossary](glossary.md)'s; the grid itself is the [pattern editor](pattern-editor.md)'s. ## Arming a slot The PROJECT page's SETUP section has a DUSK row of eight switches, `DUSK1` .. `DUSK8`. On one, `SHIFT+LEFT/RIGHT` turns it on: ``` DUSK1 ON - a morphing wavetable voice, on CH41 patch K01 IT cap 40 ``` The summary line under the switches counts the result (`1 DUSK column · IT's samples as morphing wavetables · IT cap 40`): each slot takes one of the song's channels, `CH41` for DUSK1 up to `CH48`, and the IT side stops at 40. On the grid the column stands in the synth block, between the channels and the SID columns, headed `DUSK1`. Switching a slot off parks its column — `DUSK1 OFF - its column is parked, not deleted (switch on to get it back)` — the notes stay. Only a project can hold a patch. A bare `[IT]` session refuses — `[IT] is a bare Impulse song - DUSK's patches live in the .zon, so SAVE AS a project (or NEW) first` — and a session with a SID-Wizard module (`[SWM]`, `[CO]`) has no DUSK row at all: the module brings its own chips. ## The DUSK column Its fields are note · instrument · volume · effect. `ALT+LEFT/RIGHT` jumps into the block (`DUSK1 - the DUSK block (4 synths)`), and `ENTER` on each field says what it takes: - **note** — *the DUSK note column plays notes - one cell is a whole CHORD when the patch's VOICES say so.* `===` releases the note and its tail plays out; `^^^` cuts it. - **instrument** — a K## number. A typed note stamps the slot's current patch (the footer's `P01` is the IT side's). `ENTER` on a filled field jumps to the patch: `K01 SLIDE303 on DUSK1 - TAB back to the pattern`. - **volume** — *a DUSK cell's volume IS velocity, 0-64 - the VEL binding on the MACRO tab ranges it.* An empty cell is full velocity. - **effect** — the column's own list, THE DUSK COLUMN'S EFFECTS: | effect | does | |---|---| | `Gxx` GLIDE TO NOTE | xx = cents per TICK toward the cell's note, no retrigger | | `Fxx` PITCH SLIDE UP | xx = cents per TICK, while the command is on the row | | `Exx` PITCH SLIDE DOWN | xx = cents per TICK - 00 repeats this column's last one | | `Zxx` MACRO VALUE | xx = 00-7F into the macro SFx picked; MACRO binds it | | `SFx` SELECT MACRO | x picks the macro Zxx sends into - SF0 = M01, sixteen slots | | `SDx` NOTE DELAY | x = ticks the WHOLE cell waits before it lands | | `a`–`d` DUET FX | the four send levels, as on a channel ([mixer](mixer.md)) | `SFx` and `SDx` sit under `Sxx THE S FAMILY` in the picker. `ALT+F9` mutes the slot (`DUSK1 MUTED (never saved)`), `ALT+F10` solos it (`SOLO DUSK1 on (1 soloed)`); `SPACE` turns JAM on here as on every column (`JAM MODE - piano plays, SPACE returns`). ## The K## list `F4` opens the instruments page; `TAB` rotates to `K## PATCHES 05/20` — the list exists while a slot is armed, and holds `K01` .. `K20` (hex: thirty-two). Every slot holds a patch: a fresh one is `AFTERGLOW`, the built-in default (built-in table, ADSR `00F6`, no filter). `RIGHT` edits, `SPACE` jams (*the piano plays this patch on the selected slot*), `Ctrl+D` copies, `BKSP` puts `AFTERGLOW` back, `[IMPORT]` imports from another project ([instruments](instruments.md)). The editor's top strip is `DUSK · VOICE TABLES MOD MACRO · [OSC] · K01 SLOT ◀ 1/8 ▶`. `UP` reaches it, `LEFT/RIGHT` walk the four tabs and the face follows; `[OSC]` puts the scope band up — *it draws what the keyboard plays (ALT+O does the same)* ([visuals](visuals.md)); the SLOT selector picks the armed slot the keys play — `SHIFT+LEFT/ RIGHT`, or a digit `1`–`8` — and the tabs show that slot's patch (`DUSK2 - the tabs show K02 CHORD, the piano plays this slot`). Everywhere: arrows move, digits type, `SHIFT+arrows` nudge, the `▸` line explains, `ESC` goes back to the list. On NAME the keys type the name; step down a row before `SPACE` to jam. ## VOICE | field | what it is | |---|---| | SAMPLE | `BUILT-IN` (`$00`) is the built-in morph table, saw > pulse > sine; a P## number names the song's sample slot the frames come from | | FRAME | samples per cycle: frames = sample length / FRAME; 2048 is the Polyend standard | | MORPH | the position across the frames in %, a blend of the two nearest — never a jump | | ALIAS | `clean`: high notes read band-limited copies; `raw`: every note reads the unfiltered frames, the aliasing on purpose | | ADSR | four nibbles, the 6581's own times: attack 2 ms .. 8 s, decay 6 ms .. 24 s, sustain level (F = full), release 6 ms .. 24 s (6 = ~204 ms) | | LEVEL | the patch's own gain, 0..64; 64 is unity | | AMP SRC | `adsr`: the nibbles shape the note; `env a`..`d`: that envelope becomes the VCA, the nibbles dim, the gate is held until it ends | | TRIG | what a `Gxx` onto a released tail does: `keep` re-attacks from where the release stands, `zero` from silence | | FILTER / RES | the cutoff a note starts from, `000`–`7FF` = 20 Hz–20 kHz, and the resonance `00`–`FF`: `B4` rings, `F0` is the edge — past it the loop self-oscillates | | LP BP HP | the outputs; they sum (LP+HP is a notch), all off = no filter in the path | | DRV | the drive into the filter, 64 = unity: low sings a whistle true, high bites | A sample is read as frames of FRAME samples each; a patch on an empty sample slot plays nothing. ### VOICES — the chord from one cell `VOICES` is how many oscillators a note gets, 1 to 8; a new note picks the count up. The rows below shape them: `STRUM` starts each voice so many ms after the one before, left to right; `WIDTH` spreads them across the slot's own stereo (0..64, the far side only attenuates); `PHASE` is `spread` (voices 2..n start at random phases) or `align` (every oscillator starts at phase 0, the coherent punch); `INT` gives each voice its interval in semitones — a chord from one cell — and `DET` its detune in cents (the default ladder is DUST's own, grown outward). Cells past the VOICES count are dimmed. The line under the grid is the slot's pool, live: `pool: 1 notes, 7 of 16 voices · a new note releases the last · when full, the oldest is stolen whole`. ## TABLES *MORPH, PITCH and FILTER scanned per NOTE: every note reads them from the top* — three tables side by side, one cursor. Each has a header row and a loop row: | cell | what it is | |---|---| | clock | the table's own speed per sounding note, in `Hz` (free-running), `/tk` (ticks per step) or `/rw` (rows per step); the number converts when the unit changes | | direction | `fwd` forward · `rev` reverse · `png` ping-pong · `rnd` random | | `L04` | how many steps the table has; 0 disables it | | `00 - 03` | where the loop starts (put it on the last step for a one-shot) and ends (00 = the last step) | A MORPH step is a mode and a value: `-` hold, `=` set the morph to a % of the frame axis, `+` add every step (a sweep). A PITCH step: `+` semitones, `=` absolute note, `~` cents, `>` glide to. A FILTER step is three cells — the cutoff (`.` leaves it where the table put it), the resonance, and the outputs as bits (1 LP, 2 BP, 4 HP). The row after the last step is the APPEND row: type a value or nudge it and the step is born. The line under the tables converts every clock into steps per second at the song's tempo (`morph 4.2/s pitch 50.0/s filt 50.0/s per NOTE`). ## MOD *4 LFOs (slot-wide) + 4 envelopes (per note) + 8 routes; the panel below says which layer did what.* - **LFO A–D**: SHAPE (`off`, `tri`, `saw+`, `saw-`, `sqr`, `sine`, `s&h`, `rand`; an LFO costs nothing while off), RATE and its UNIT (Hz, ticks per cycle or rows per cycle), DPTH — the LFO's own level in % of full swing, RTRG (`free` breathes across the notes, `note` restarts the shared run at every note-on), QNT (0 smooth, N steps), PH (where in the cycle it starts, `00`–`FF`), FADE (the depth ramps in over this many ms from the note). One LFO per slot, shared by every sounding note. - **ENV A–D**: DLY, ATK, HLD, DEC in ms, SUS% (a fresh envelope is a constant 100), REL in ms from where it stood when the note let go, CRV (`lin` walks, `exp` starts slow, `log` arrives slow), LOOP (on: the decay's end goes back to the delay). They run per note; a tail keeps its own. - **RTE 1–8**: SOURCE → DESTINATION by AMOUNT with a CRV; `ENTER` on either opens its list. Sources: `lfo_a`..`d`, `env_a`..`d`, `morph_pos` (the read position on this note), `note` (centred on C-5), `velocity` (the vol column, 0-64 as 0-1), `random` (per note, seeded), `chan_fx` (what the column sent). Destinations: `cutoff` (on top of what the FILTER table holds), `resonance`, `drive`, `morph` (a slow LFO here is the classic wavetable sweep), `pitch` (cents, summed — vibrato), `amp` (the level before the mixer). The RESOLUTION panel under the routes lists every parameter something moves — BASE (the patch), HELD (what a table holds), MOD (what the routes add), FINAL, and FROM, the layer that did it — live while a note sounds (`CUTOFF 17C 190 000 190 filter 06`), `(nothing sounding)` otherwise. ## MACRO *What the PATTERN can say to this patch: the vol column's binding + the 16 SFx slots.* One row per binding — LABEL, DESTINATION, MIN, MAX, CRV and NOW, the live value: - **VEL** is the velocity binding, fed by the vol column whatever you call it: MIN is where a volume of zero lands, MAX where full velocity lands, in level steps 0–64 — keep MAX at 0 and a full note is untouched; by default `amp -64 .. 0`. - **M01**–**M10** (sixteen, in hex) are the macros: `SFx` on the column selects one (`SF0` = M01) and `Zxx` sends `00`–`7F` into it, walked from MIN to MAX in the destination's own units (cutoff `0`–`2047`, for one) on the CRV: `lin`, `exp` or `log`. ## Elsewhere Every armed slot has a strip on [the mixer](mixer.md) — a fader in dB and a stereo BALANCE. The scope band shows a slot from its `[OSC]` button or `ALT+O` ([visuals](visuals.md)). From the command line, `duet --dusk-test out.wav` renders the built-in patch through the built-in table (`dusk-test: DUSK1 = K01 "AFTERGLOW" (built-in table, 32 frames x 512, ADSR 00F6)`) — [cli](cli.md) has the rest.