A drone instrument for slowly breathing clusters, built to one brief: the sleep concerts Robert Rich has played since 1982 — dense chords in just intonation, no rhythm, changes that take minutes, a piece that can run all night without repeating and without anyone touching it. Almost every decision in the instrument follows from taking that brief literally, including the ones that cost it features other synthesizers have.
VST3 plugin and standalone application for Windows (x64). Licence: AGPL-3.0.
Noctuary-2.0.3-Setup.exe installs the standalone, the VST3 and the preset library, and offers to fetch the sample library as well. Nothing else has to be installed: the runtime is linked in. There is a portable zip for anyone who would rather not run an installer, and a manual — every tab of the panel as a picture, what each knob does, and seven chapters on why the instrument is built the way it is, with the mathematics and the references.
Requirements: Windows 10 or 11, a 64-bit processor with AVX2 (every x86-64 since 2013), and a VST3 host if you want the plugin. The synthesizer and its 14592 presets take under 100 MB on disk; the sample library is 100 GB and entirely optional — without it the 256 built-in presets and everything that does not name a recording still play.
Every note carries a distance: 0 at the ear, 1 the infinite background. Brightness, level, dryness, presence, the interaural time difference and the reverb it reaches all follow from that one number, so depth is a landscape rather than an effect. The near plane is dry, bright and close; the far plane is 100 % wet, dark, wide, and pulled towards the centre while the foreground stays wide — which is what the ear reads as distance.
- Sixteen voices, four equal source slots each, any slot any of twenty-four types. Nine carry the drone: an additive bank whose partials live their own lives, a harmonic table, a classic wavetable of cycles, two-operator FM, granular texture from a recording, a thirty-two-band spectral model, a Paulstretch, a bowed string and ten noise colours. The other fifteen belong to the near layer below. A Vector reads four slots as the corners of one square, and a struck string, wood or metal sits on top. Each slot enters on its own clock: up to half a minute of silence after the note, then a fade or a sixteen-breakpoint shape of its own, so a texture can arrive twenty seconds under a wavetable that is already sounding. A slot can also be given a role — the lowest note of the cluster, an inner one, the highest — so the cello under the chord is not also the chime on top of it.
- Two filters. Ten models with a wavefolder, and a Z-plane morphing filter after the E-mu Morpheus with 155 shapes on a cube rather than a square, plus a modal mode that turns it into a struck body.
- A spatial model with a true interaural time difference, Doppler on moving voices, headphone externalisation, air absorption, and a vertical axis heard through the pinna's elevation notch.
- Three reverb tiers. A near room; a far reverb of eight feedback lines with four characters (classic, scattering, colourless, and a rotating matrix whose modes drift instead of ringing in one place) plus diffusion, rotation, envelopment and a co-modulation that breathes the whole background to one slow envelope so the foreground is heard past it; and a convolution room that takes two impulses and morphs between them inside the one convolution — partitioned in three sizes with the long partitions' work spread across the blocks before their deadline, so a minute of hall costs about 1.4 % of a core instead of arriving as a spike.
- A grain cloud in the Aetherizer lineage. Grains of the recent foreground, transposed and dropped into the background: feedback so they hear their own echoes, a shift on every pass of the loop, resonators that ring on after their grain has ended, scatter that follows the instrument's own tuning rather than a fixed twelve-tone menu, and onsets as a self-exciting process so the grains arrive in flocks.
- The Cosmos: a parallel path of frequency shifter, tuned resonators, a vowel filter, a spectral nebula and a self-regulating shimmer loop. It adds and never replaces.
- A near layer with a second, smaller conductor of its own: a flute, a murmur, a bowl, ice, drops or a clip playing close to the ear as a note, a gliding phrase or a Berlin-school shift register that mutates, plus nine signal sources — whistler, shaker, chime, geiger, tube, Krell, beacon, morse, dial. It is a bank beside the sound presets, 108 of them in twelve families, so a night's foreground can be chosen once and the backgrounds changed under it.
- A conductor that plays all night. The Cluster Brain chooses notes from the scale, places them on the planes and holds them for minutes. It judges a chord several ways at once, finds the key it has drifted into, makes its clock self-exciting — events that cause events — and tunes each arriving note pure against what is already sounding.
- Thirteen tunings: twelve just and historical tables, Scala files, and one that sweeps the instrument's own roughness curve and puts a degree wherever it dips, so the tuning follows the sound.
- Modulation everywhere: eight LFOs, six hand-drawn envelopes, eight macros, four coupled Kuramoto oscillators, a Lenia field, the Lorenz and Rössler attractors on a scale of minutes, aftertouch, wheel and slide — forty-nine sources through a matrix of thirty-two routes onto any knob, including the modulators' own.
- No compressor, no limiter, no dithering. What you hear is the dynamics of the drone.
Every rate that can sit on a grid has a sync choice beside its free knob, from 64 bars to 1/32 with dotted and triplet values. Every voice, plane and effect answers to MIDI, MPE, OSC or hand tracking through the same parameters.
14592 presets — 256 compiled into the instrument and 14336 in 56 packs, each pack written in the spirit of an artist who works in one corner of the drone repertoire. Nothing in the library is described; everything is measured. Every preset is rendered offline for a minute and nine descriptors are taken from the render: how bright, how dense, how wide, how far the sound travels over that minute, how rough its partials are against each other, how much of it comes back from the far planes. Those nine become the browser's columns, the level matching, and the position on the map.
The map is a free cloud laid out by springs on a nearest-neighbour graph, dense where the library repeats itself and empty where it is thin, turned until dark is left and evolving is up, and coloured by groups the same nine numbers fall into. Put the cursor between points with map blend on and the instrument glides to a blend of the presets around it — a sound nobody saved. A point on the map is where a preset sounds, not where somebody put it.
Sort and filter by family, character, motion and features, or search; star what you like and the favourites rise to the top of any sort and ring gold on the map. A route walks the map by itself between waypoints. A journey is a list of presets for an evening that plays itself — each held for a time drawn from a range, then crossfaded into the next — and 119 of them ship with the library, a journey and a night for every pack and a crossing for every family.
Beside the presets: 8686 samples (5748 textures and 2938 field recordings, every one of the
latter made seamless by construction), 2191 wavetables on three shelves, and 1100 impulse
responses — not only rooms but tuned partial banks that ring in key, inharmonic modal metal,
reversed swells, combs and pipes, and struck objects cut from the recordings, 421 of them as a/b
pairs for the room morph. All of that is generated for this instrument, and the clips carry the
artist they were written for, so a pack plays the material made for it. Beside it sits an archive
of 931 recordings that are not generated at all: Mars wind and marsquakes and the Webb
sonifications from NASA, 724 cylinder and early-radio transfers from the Library of Congress, and
120 shortwave and numbers-station captures — all public domain, each one credited to its source in
Library/Archive/SOURCES.md.
| Directory | What | Depends on |
|---|---|---|
Core/ |
The whole synthesizer: parameters, tuning, voices, spatial routing, effects, conductor, presets, engine. Pure C++20, no allocations while rendering. | nothing |
Plugin/ |
JUCE wrapper: VST3 + standalone, the panel, preset browser and map, state. | JUCE 9 (fetched by CMake) |
Tools/render/ |
ambient_render: offline renderer to WAV with per-second measurements, journeys and a rule-book audit of the conductor. |
Core |
Tools/library/ |
The library pipeline: generates, renders, measures and lays out the presets. | Python, numpy |
Tests/ |
The self test, the host test, the race test and the SIMD path tests (below). | Core, JUCE for the host test |
Deploy/ |
build_release.ps1 builds, checks and packages; Noctuary.iss is the installer. |
Inno Setup 6+ |
Quest/ |
A native Meta Quest app against the same core: OpenXR, hand tracking, Oboe. Builds; not yet run on a headset. | NDK, OpenXR, Oboe |
docs/concept.md |
Sound-design and architecture notes. |
cmake -S . -B build -G "Visual Studio 18 2026" -A x64
cmake --build build --config ReleaseOutputs: the VST3 under build/Plugin/Noctuary_artefacts/Release/VST3/ (copy the folder to
C:\Program Files\Common Files\VST3), the standalone beside it, ambient_render under
build/Tools/render/Release/, and the tests under build/Tests/Release/. The first configure
downloads JUCE. -DAMBIENT_BUILD_PLUGIN=OFF builds only the core and the tools, which needs no
JUCE and also builds on Linux.
ambient_selftest measures the instrument: tuning, envelopes, the conductor, determinism, and the
largest sample-to-sample step of every render it makes. ambient_hosttest measures the plugin
around it — rates from 44.1 to 96 kHz and blocks from 16 to 2048 with mismatched short blocks
between them, a state that comes back exactly as it went out, programs changed while audio runs,
and four seconds of two threads writing every parameter while it plays. Run it without
AMBIENT_MUTE: it measures levels. ambient_racetest renders on one thread while another changes
everything a window can change, as fast as it can; it exists because nearly every serious fault
this instrument has had was a handover between those two threads.
build/Tests/Release/ambient_selftest.exe
build/Tests/Release/ambient_hosttest.exe
build/Tests/Release/ambient_racetest.exe 4The hot inner loops — the partial bank, the grain ring, the convolution — exist as AVX2, NEON and
scalar. ambient_banktest, ambient_convtest and their _neon and _scalar variants check that
the three agree sample by sample, and each one names the path it actually took, because a test that
compares a vector path with a scalar one passes trivially when no vector path was compiled.
AMBIENT_FUZZ=1 turns the host test into a tool: it sets every parameter at random, then moves one
section at a time while a chord plays, and names any section whose sound stops being a number.
Before a release, two more that do not live here. pluginval at strictness 10 exercises the VST3 through the format itself. The thread sanitizer exists only on Linux, which is where the framework-free core comes in:
cmake -S . -B build-tsan -DAMBIENT_BUILD_PLUGIN=OFF -DCMAKE_BUILD_TYPE=RelWithDebInfo \
-DCMAKE_CXX_FLAGS="-fsanitize=thread -g -O1" -DCMAKE_EXE_LINKER_FLAGS="-fsanitize=thread"
cmake --build build-tsan -j && setarch $(uname -m) -R ./build-tsan/Tests/ambient_racetest 60powershell -File Deploy\build_release.ps1Builds in its own tree with the runtime linked in and AVX2 on, runs the tests in that exact
configuration, refuses to package a binary that still asks for any redistributable — Microsoft's or
Intel's — and leaves a setup and a portable zip in Deploy\out with their SHA-256 sums.
Releases are built with Intel's oneAPI compiler, which is about a fifth faster through the plugin
under load than MSVC. It puts a generative instrument on a different floating-point trajectory, so
it plays a different take of the same patch; over sixty presets the descriptors the map is laid out
from move by 5 % of a typical distance between two presets and the loudness by a hundredth of a
decibel, so the map and the loudness matching hold. -Toolchain msvc builds the same source with
Microsoft's compiler, for comparing the two rather than for packaging.
The sample library is 100 GB of FLAC split across 57 archives on its own release tag; the installer downloads them with your consent and verifies each against a manifest, and the portable zip points at them in its README.
It has no compressor, no limiter and no dithering, and does not intend to — mastering is a separate craft with its own tools. The four-pole ladder filter is not zero-delay. The Quest application builds against the same core and has not yet been run on a headset. The spectral model is thirty-two bands and one partial per band, so a dense chord in one band comes back as its loudest member plus noise. The manual's last chapter lists the rest of the caveats in full, because the instrument's manual is also its record.
AGPL-3.0. The generated samples, wavetables and impulse responses are the author's own and ship
under the same terms. The archive recordings are public domain and credited file by file in
Library/Archive/SOURCES.md; the only measured rooms in the impulse folder are the Aula Carolina
responses from the Aachen AIR database, under their own permissive licence, credited in
Library/Impulses/CREDITS.txt. No material is sampled from, or affiliated with, any of the artists
the preset packs are named in the spirit of.