galdr

A terminal grid synthesizer. Signal flows downward through a field of single-glyph unit generators; every incoming MIDI note voices the whole grid; the mix is rendered low-latency to PipeWire. It is orca's voice — the same esoteric, spatial approach to programming, but for making sound instead of sending events.

orca-rs  ──MIDI/OSC/UDP──▶  galdr  ──PipeWire──▶  speakers
   compose the pattern       voice it       (spectrust -p visualizes it)

The grid

Signal flows down: each cell takes the sample from the cell above as its input. Glyphs are UPPERCASE operators. A digit 0–9 to the left/right is a constant parameter; a lowercase letter a–z reads MIDI CC (a = CC 0).

glyph	unit generator	left / right param
O	sine	ratio
A	saw	ratio
U	pulse	width
V	triangle	—
N	noise	—
L H B	low / high / band-pass (SVF)	cutoff / resonance
E	envelope (gated by the note)	attack / release
S	soft clip (tanh)	drive
C	hard clip	threshold
F	wavefolder	amount
D	decimate / bitcrush	rate
G	gain	amount
R	ring modulator	ratio
M	mix — adds the cell to its left	—
!	output to master	—

Each ! sums into the master, so parallel columns stack timbres or voices. A note plays every column at once.

Example — a filtered saw with an envelope:

A        saw at the note pitch
L        lowpass, cutoff from the digit to its left...
E        ...enveloped by the note gate
!        ...to master

Editing the grid recompiles and hot-swaps the running program without dropping audio. There is no embedded scope — run a spectrum analyzer (e.g. spectrust) on the side if you want one.

Usage

galdr [--latency <frames>] [--poly <n>] [--rate <hz>] [--midi-name <s>]

galdr creates a virtual MIDI input port named galdr; connect orca or any sequencer/DAW to it. --midi-name connects to an existing port instead. Cursor keys move; type a glyph to place it; Backspace clears; Esc quits.

Runtime deps: PipeWire and ALSA (MIDI). Built in Rust; reuses the native PipeWire path from spectrust.