Bendik Aagaard LynghaugandClaude Fable 5.1
e9836c2467
Six new letters: T LFO (rate/shape, tremolo with an input), I slew limiter, Q pitch quantizer (scale/octaves, transposes the oscillators below it), J stepped random, P phaser (voice or master), Y comparator. Any control op left of an operator feeds its left param, as K does. Punctuation maths with the cell to the left: + - * (signal or constant), % attenuverter, | max, & min, ~ sample-and-hold on a rising trigger. A column's input is now only an operator above it, so a channel tag or param glyph above T/J no longer flips them into VCA mode on silence. Height resize moves from _ + to [ ] since + is a glyph now. examples/modular.galdr: wobble bass, Q arpeggio, J crackle, Y/K pulse. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
348 lines
14 KiB
Markdown
348 lines
14 KiB
Markdown
# galdr
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A terminal **grid synthesizer**. Signal flows downward through a field of
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single-glyph unit generators; every incoming MIDI note voices the grid (or the
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columns tagged with its channel); the mix is rendered low-latency to PipeWire.
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It is orca's voice — the same esoteric, spatial approach to programming, but
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for making sound instead of sending events.
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```
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orca-rs ──MIDI + UDP──▶ galdr ──PipeWire──▶ speakers / stems
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compose the pattern voice it (spectrust -p visualizes it)
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```
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## The grid
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Signal flows **down**: each cell takes the sample from the cell above as its
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input. Glyphs are **UPPERCASE** operators. A digit `0`–`9` to the left/right is
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a constant parameter; a lowercase letter `a`–`z` reads MIDI CC (`a` = CC 0).
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| glyph | unit generator | left / right param |
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|---|---|---|
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| `O` | sine | ratio |
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| `A` | saw | ratio |
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| `U` | pulse | width |
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| `V` | triangle | — |
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| `N` | noise | — |
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| `L` `H` `B` | low / high / band-pass (SVF) | cutoff / resonance |
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| `E` | envelope (gated by the note) | attack / release |
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| `S` | soft clip (tanh) | drive |
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| `C` | hard clip | threshold |
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| `F` | wavefolder | amount |
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| `D` | decimate / bitcrush | rate |
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| `G` | gain | amount |
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| `R` | ring modulator | ratio |
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| `X` | FM: sine at the note pitch, phase pushed by the cell to its **left** (and above) | — / index |
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| `M` | mix — adds the cell to its **left** | — |
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| `K` | control envelope: 1 at note-on, decays to a floor; no audio input | decay / floor |
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| `T` | LFO, 0–1, retriggered per note; with an input it is a tremolo | rate / shape |
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| `J` | stepped random (sample-and-hold noise); with an input it chops it | rate / amount |
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| `I` | slew limiter (lag) | rise / fall |
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| `Q` | pitch quantizer: transposes the oscillators **below** it | scale / octaves |
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| `Y` | comparator: 1 while the input is above the threshold | smoothing / threshold |
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| `P` | 4-stage phaser | rate / depth |
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| `+` `-` `*` | add / subtract / multiply the cell to its **left** | signal or constant |
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| `%` | attenuverter | gain (0 = −1 … 9 = +1) / offset |
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| `\|` `&` | max / min of input and the cell to its **left** (gate OR / AND) | signal or constant |
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| `~` | sample-and-hold: holds the input when the cell to its **left** rises | trigger |
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| `!` | output to master | — |
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`K`, `T`, `J`, `I`, `Q`, `Y` and the maths glyphs output a *control value*:
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placed to the **left** of another operator any of them becomes that operator's
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left param, scaled 0–9. `2KL5` is a lowpass whose cutoff starts open and
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decays (2) to the floor, with resonance 5. That's the 303 filter envelope.
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`4TL5` is the same filter wobbled by an LFO. See [the modular glyphs](#the-modular-glyphs).
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Each `!` sums into the master, so parallel columns stack timbres or voices.
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An untagged column plays on every MIDI channel.
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### Params
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A param cell is a digit `0`–`9` (constant), a lowercase letter `a`–`z` (a
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register: MIDI CC `a` = CC 0, or set over UDP), or one of three per-note
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values: `@` velocity, `^` key tracking (note number), `?` a random value rolled
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at note-on. All read on the same 0–9 scale, so `@L` is velocity-to-cutoff and
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`?O` detunes every hit a little differently.
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### Channel tags
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A base-36 glyph directly **above** a column's top operator is that column's
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MIDI channel: `0`–`9`, `a`–`f` for channels 1–16 (orca's numbering). The
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column then only voices notes on that channel. A `>` right of the tag makes
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the channel **mono-legato**: a note that overlaps the previous one slides the
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running voice to the new pitch over 60 ms without retriggering the envelopes,
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the 303 slide. From orca, make the step's note length longer than the gap.
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### Acid
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`examples/acid.galdr`, a 303 line on channel 1:
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```
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...0>
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...A. saw (U for the square)
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.2KL@ K sweeps the cutoff (decay 2, floor open-to-closed); accent = velocity -> resonance
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...E1 short amp decay
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..3S. overdrive
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...!.
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```
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```
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1....2.... column 0 is channel 1 (a filtered saw),
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A....O.... column 5 is channel 2 (a plain sine)
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L....E....
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E....!....
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!.........
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```
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### The modular glyphs
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The six letters and the punctuation are the eurorack side of galdr: control
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sources, processors and utilities that patch together through the same
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left-of-an-operator rule as `K`. Everything is on a 0–1 control scale, so the
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pieces combine.
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| glyph | module | left | right |
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|---|---|---|---|
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| `T` | LFO (0–1, restarts at note-on) | rate: 0 = 0.05 Hz … 9 = 25.6 Hz | shape: 0 sine, 1 tri, 2 saw, 3 ramp down, 4 square, 5 sample-and-hold |
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| `J` | random voltage: a new value every step | rate (as `T`) | amount |
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| `I` | slew limiter / lag processor | rise: 0 = 1 ms … 9 = 0.5 s | fall |
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| `Q` | quantizer | scale (below) | span in octaves |
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| `Y` | comparator | edge smoothing (0 = hard) | threshold, 0–9 = 0–1 |
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| `P` | phaser (voice or master) | rate | depth |
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`Q` scales: 0 chromatic, 1 major, 2 minor, 3 pentatonic major, 4 pentatonic
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minor, 5 dorian, 6 phrygian, 7 lydian, 8 mixolydian, 9 blues. It reads a 0–1
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control from the cell above, snaps it to the scale and transposes every
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oscillator *below it in the column* by that many semitones. Its own output is
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the snapped value, so it can also drive a param.
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`T` and `J` with an audio input become VCAs on that input (tremolo, random
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chopping). `Y` on an audio input is a comparator in the eurorack sense: a saw
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into `Y4` is a pulse wave whose width is the threshold.
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The punctuation is maths with the cell to the **left**. If that cell is an
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operator its raw signal is used; a digit or register is a constant on the
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0–1 scale (`9` = 1).
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| glyph | out |
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|---|---|
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| `+` | input + left |
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| `-` | input − left (no input: an inverter) |
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| `*` | input × left: a VCA when a control is left of it, a ring mod when an oscillator is |
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| `%` | input × gain + offset, gain from −1 (`0`) through 0 (`4`/`5`) to +1 (`9`) |
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| `\|` | max(input, left) — OR for gates, half-wave rectifier with nothing to the left |
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| `&` | min(input, left) — AND for gates |
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| `~` | sample-and-hold: holds the input whenever the left cell rises through 0.5 |
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A few patches, each one column plus its helpers:
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```
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..A. saw
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7TL6 wobble bass: a 6.4 Hz sine LFO sweeps a resonant lowpass
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..!.
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```
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```
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..1T2 a 0.1 Hz ramp...
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...Q. ...quantized to the major scale over one octave...
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...A. ...transposes this saw: a slow arpeggio from a single held note
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...!.
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```
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```
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..N. noise
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.9J* random voltage at 25.6 Hz as a VCA: crackle
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..!.
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```
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```
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...A. saw
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.6T~. a 3.2 Hz LFO to the left of ~ clocks the hold: a stepped saw
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...!.
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```
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```
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..A..
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..Y4. comparator turns the saw into a pulse
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3K*.. K to the left of * is the VCA: a plucky pulse
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..!..
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```
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`examples/modular.galdr` strings four of these into a kit, one per MIDI
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channel, with a phaser on the master:
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```
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..0.....1......2....3..
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..A....2T2.....N....A..
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7TL6...1Q1...9J*....Y4.
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..E3....A.....5B5.3K*..
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..!....4L2.....E2..1H..
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.3P5....E4.....!....!..
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........!..............
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```
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- **wobble bass** (ch 1): saw, a 6.4 Hz LFO sweeping a resonant lowpass.
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- **arpeggio** (ch 2): a 0.2 Hz ramp through `Q` (major, one octave) climbs the
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saw a scale step every 0.7 s from a single held note.
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- **crackle** (ch 3): noise chopped by `J` at 25.6 Hz through a bandpass.
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- **plucky pulse** (ch 4): `Y` turns the saw into a pulse, `K` left of `*` is
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the VCA, `H` removes the pulse's DC.
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Watch the tag rule when you stack control ops: a digit directly above `T`,
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`K` or any other operator at the top of its column is read as a channel tag.
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### The master chain
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Operators placed **below** a column's `!` no longer run per voice: they
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process the summed stereo master, in series, in column order. Any filter or
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shaper works there, plus two master-only effects:
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| glyph | effect | left / right param |
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|---|---|---|
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| `Z` | delay | time (0 = 100 ms … 9 = 1 s) / feedback |
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| `W` | stereo chorus | rate / depth |
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| `P` | phaser (also works in a voice) | rate / depth |
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```
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A
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!
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5L lowpass on the whole mix
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3Z6 then a 400 ms delay with lots of feedback
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.W then a slow chorus for width
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```
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Editing the grid recompiles and hot-swaps the running program without dropping
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audio. There is no embedded scope — run a spectrum analyzer (e.g. `spectrust`)
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on the side if you want one.
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## A drum kit (one drum per MIDI channel)
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A note voices every column tagged with its channel, so give each drum its own
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channel and let orca pick the channel per hit. `examples/drums.galdr`:
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```
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.0..9....a...b.
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.A..O9...N...N.
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@L5.EX9.6B5.8H.
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.E2..E1..E1..E0
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2S...!..3S...!.
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.!.......!.....
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```
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- **bass** (tag `0`, MIDI ch 1): saw → lowpass with the cutoff from velocity
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(`@`) and resonance 5 → envelope, release 2 → soft clip 2 → out.
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- **kick** (tag `9`, ch 10): the left column is a sine into an envelope with
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no `!`, it exists only as a modulator. The `X` next to it is a sine at the
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note pitch, phase-modulated by that decaying signal with index 9: bright at
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the hit, a clean low sine a moment later. Play it a low note (C1–C2).
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- **snare** (tag `a`, ch 11): noise → bandpass 6, resonance 5 → short
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envelope → soft clip 3. A mid note sets the bandpass body.
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- **hats** (tag `b`, ch 12): noise → highpass 8 → envelope with release 0.
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Note length from orca is the open/closed control.
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From orca, `:` with the channel glyph per drum, e.g. `:93C` for the kick,
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`:a3D` snare, `:b5F` hats, `:02C` bass. With `--stems 12` each drum also has
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its own `galdr.ch*` node to record.
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## An orchestra (the big example)
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`examples/orchestra.galdr` is ten sections on ten MIDI channels, each in a
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four-column block `[left param | chain | right param | gap]`, so every digit
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is a knob. It uses most of the vocabulary: velocity (`@`) into a filter and
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into an FM index, key tracking (`^`), per-note random (`?`), two modulator
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columns feeding `X`, registers set from orca (`k` and `z`), and a hall on the
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master chain (highpass, chorus, delay with feedback from `z`).
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```
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.0...1...2...3...44..5...6...7...8...9..
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.A...A...A2.2U...NO.1U..5U...O7..A...V..
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@L2.3L3.1EX@4L1.9HE36B6.6L1..EX3^L?.kL2.
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4E5.3E4..1E23E3.1E!.2E2.2E2..0E40E3.7E7.
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.!..2S...2S.1S..2G..1F...!....!..!..9G..
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1H...!....!..!...!...!...............!..
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2W3.....................................
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4Zz.....................................
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```
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| ch | tag | section | how |
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|---|---|---|---|
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| 1 | `0` | strings | saw, lowpass cutoff from velocity, slow envelope; the hall hangs under its `!` |
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| 2 | `1` | low strings | saw, lowpass 3/3, soft clip |
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| 3 | `2` | brass | a saw-envelope modulator column drives `X`, FM index from velocity |
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| 4 | `3` | horns | narrow pulse, lowpass, soft clip |
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| 5 | `4` | flute | breath noise (highpass, short env, gain) beside a sine |
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| 6 | `5` | reed | pulse width 1, resonant bandpass, fold |
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| 7 | `6` | clarinet | square, lowpass |
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| 8 | `7` | timpani | sine-envelope modulator into `X`, long release, play C1 to C2 |
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| 9 | `8` | harp | lowpass cutoff key-tracked, resonance random per pluck, pluck envelope |
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| 10 | `9` | choir | triangle, lowpass cutoff from register `k`, very slow envelope |
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Load it with `galdr examples/orchestra.galdr`, or over UDP with `#orchestra`
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once it sits in the patches directory. `;k5` and `;z3` from orca set the choir
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brightness and the hall feedback live.
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## Stems
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`--stems n` adds one mono PipeWire node per channel tag, `galdr.ch0` …
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`galdr.ch<n-1>` (named by the tag glyph), each carrying the dry sum of that
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channel's voices, sample-aligned with the master. They are not auto-connected:
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patch them in a graph tool, or record them with a multitrack recorder such as
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`stems`, and master the session later.
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## UDP control from orca
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galdr listens on UDP port 49161 (orca's `;` operator sends there). One
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datagram carries one or more commands, separated by whitespace or `;`:
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| command | effect |
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|---|---|
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| `k7` | set register `k` to 7 of 35 (base-36), read by `k` param cells |
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| `*3` | bang column 3: a 5 ms gate on that column alone, no note needed (drums, plucks) |
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| `@34O` | write glyph `O` at column 3, row 4 — orca patches the synth itself |
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| `@34.` | clear that cell |
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| `#verse` | load the patch `verse.galdr` from the patches directory |
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Bangs and register sets go straight into the audio thread; grid commands are
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applied by the editor and recompiled like a keystroke.
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## Patches
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A patch is plain text: one line per row, `.` for an empty cell, `#` lines
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ignored. `galdr file.galdr` opens one and `Ctrl+S` writes it back. With no
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file, galdr works on **today's** patch, `~/hometaping/<YYYY-MM-DD>.galdr`:
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opened at start if it exists, written by `Ctrl+S`. That is the same dated
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naming as the orca files kept in that directory, so a session's orca pattern
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and its galdr voice sort together. `#name` over UDP loads
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`<patches dir>/name.galdr` (`--patches` overrides the directory).
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Example — a filtered saw with an envelope:
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```
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A saw at the note pitch
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L lowpass, cutoff from the digit to its left...
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E ...enveloped by the note gate
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! ...to master
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```
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## Usage
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```
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galdr [--latency <frames>] [--poly <n>] [--rate <hz>] [--stems <n>]
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[--udp <port>] [--patches <dir>] [--midi-name <s>] [patch.galdr]
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```
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galdr creates a virtual MIDI input port named **galdr**; connect orca or any
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sequencer/DAW to it. `--midi-name` connects to an existing port instead.
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Keys: cursor keys move; type a glyph to place it; Backspace clears; `Ctrl+S`
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saves the patch; `?` toggles help; Esc quits. Resize the grid with `(` / `)` (width) and `_` / `+` (height)
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by one ruler division, or Ctrl+arrows by one cell (orca's bindings).
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galdr survives a PipeWire restart: the status line shows `PIPEWIRE DOWN —
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reconnecting…` and the stream comes back on its own, voices and master-chain
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state intact.
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Runtime deps: PipeWire and ALSA (MIDI). Built in Rust; reuses the native
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PipeWire path from spectrust. `GALDR_DEBUG=<file>` appends every event that
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reaches the engine, handy when orca and galdr disagree.
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