2026-09-13 13:24:18 +02:00
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# 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 whole grid;
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the mix is rendered low-latency to PipeWire. It is orca's voice — the same
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esoteric, spatial approach to programming, but for making sound instead of
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sending events.
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```
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orca-rs ──MIDI/OSC/UDP──▶ galdr ──PipeWire──▶ speakers
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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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2026-09-13 14:06:12 +02:00
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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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2026-09-13 14:06:12 +02:00
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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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| `M` | mix — adds the cell to its **left** | — |
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| `!` | output to master | — |
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Each `!` sums into the master, so parallel columns stack timbres or voices.
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A note plays every column at once.
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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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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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## Usage
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```
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galdr [--latency <frames>] [--poly <n>] [--rate <hz>] [--midi-name <s>]
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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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Cursor keys move; type a glyph to place it; Backspace clears; Esc quits.
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Runtime deps: PipeWire and ALSA (MIDI). Built in Rust; reuses the native
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PipeWire path from spectrust.
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