Aste Signal Instruments

Aste is the neutral internal codename for a planned family of professional audio instruments. It is not the company name and must not become a permanent public namespace, bundle identifier, preset signature, or installer path.

The project combines original DSP, restrained industrial interfaces, historical engineering research, deterministic measurement, and unusually strict real-time testing. It is not a hardware-cloning exercise and does not use “analog” as a substitute for describing measurable behaviour.

Project status: Density D-01, Harmonic H-01, Sequence S-01, Loop L-01, Impulse I-01, and Field F-01 are complete working internal VST3 prototypes. All six have product-owned DSP, state, tests, industrial UIs, and universal macOS bundles. The local and hosted 67-test, sanitizer, universal signature/slice, ABI-host, and Steinberg extensive-validation gates pass for the six-product line. None is a supported release: Developer ID signing, notarization, final company identity, and DAW compatibility remain open.

The instrument family

Product	Purpose	Status
Density D-01	Parallel hard mastering compressor	Complete internal prototype; DAW validation next
Harmonic H-01	Equalizer with nonlinear band behaviour	Complete internal prototype; musical/DAW validation next
Sequence S-01	Monophonic programmed-current synthesizer	Complete internal prototype; musical/DAW validation next
Loop L-01	Tape-inspired playable memory instrument	Complete internal prototype; captured-memory recall next
Impulse I-01	Generative rhythm and transient instrument	Complete internal prototype; musical/DAW validation next
Field F-01	Playable reverb and stored-spatial-energy instrument	Complete internal prototype; musical/DAW validation next

All six products remain independent. Shared code is extracted only when two products genuinely need identical behavior or when correctness requires one implementation; no product processor links to another product.

Density D-01

Density is a mastering-oriented parallel dynamics instrument built around one musical idea: increase weight, continuity, proximity, and controlled loudness without erasing the dry signal's transient life and dimensionality.

It is not a generic compressor with a wet/dry knob. The architecture is parallel from the start:

input --+------------------------------ dry -------------------+
        |                                                       |
        + drive -> detector HPF -> continuous stereo link       |
                -> per-channel peak envelopes                   |
                -> hard gain computers -> saturation -> clip ---+-> blend
                                                                 -> output
                                                                 -> protection

The production graph currently has zero algorithmic latency. The dry and crush branches are therefore sample-aligned without a delay line, and the VST3 reports zero samples to the host. A measured 4× oversampling design remains isolated in the DSP lab because the complete graph misses the default CPU budget and has not passed musical selection. There is no hidden quality mode or silent topology change.

Controls

Control	Range	Default	Role
Drive	-12 to +24 dB	0 dB	Pushes the crush audio, detector, and positive-drive saturation
Crush	0–100%	65%	Sets the hard-compression contribution
Attack	0.02–30 ms	1 ms	Shapes transient entry
Release	20–1200 ms	180 ms	Sets recovery time
Density	0–100%	50%	Coordinates threshold, ratio, saturation, release curvature, and crush make-up
Blend	0–100%	50%	Mixes the aligned dry and crush paths
Stereo	0–100%	100%	Moves continuously from independent to fully linked detection
Output	-24 to +12 dB	0 dB	Final level trim
Detector HPF	20–300 Hz	90 Hz	Reduces low-frequency detector dominance
Protection	Off/on	On	Sample-peak output protection

Host bypass is the eleventh stable parameter. Every continuous control supports host automation, exact text entry, reset, normalization, documented smoothing, and deterministic state recall. Parameter IDs are treated as release contracts; see PARAMETER_MODEL.md.

Sound and interface

At restrained settings Density is intended to increase presence and continuity while keeping the transient-bearing dry path intact. Crush now also controls nonlinear participation, while positive Drive pushes saturation by up to 75%. At stronger settings the expanded -30 dB / 60:1 macro range becomes deliberately hard, close, and physical. The output stage is protective sample-peak clipping, not a true-peak mastering limiter.

The current 980×540 editor scales from 760×420 to 1520×840. It uses a near-black surface, off-white technical typography, a muted burgundy accent, explicit keyboard order, editable values, and signal-driven meters. There are no tabs, fake materials, rack decorations, or hidden essential controls. The full family language is documented in UI_SYSTEM.md.

Harmonic H-01

Harmonic is a four-band broad equalizer whose boost behavior includes a bounded dynamic nonlinear component. Cuts stay clean; boosts progressively add a stateful harmonic contribution without switching topology. Its revised square-root boost participation makes even modest positive boosts respond, while the full Harmonic range reaches an intentionally obvious nonlinear region. The serial graph is:

input -> Foundation -> Body -> Presence -> Air -> output
           clean cuts / nonlinear-participating boosts

Foundation, Body, Presence, and Air each expose gain and a constrained frequency range. Input, Harmonic, and Output are global. The Harmonic macro continuously coordinates the bounded-stage drive and contribution; it does not add noise, drift, or a generic post-EQ saturator. The graph is minimum-phase, uses no lookahead or oversampling, and reports zero latency.

Candidate 3 is deliberately provisional. It passed the laboratory contour, harmonic, IMD, recovery, finite-output, and CPU gates needed to justify a real plugin, but the music-machine test decides whether its four-band interaction is actually useful. The stable internal-beta contract is in docs/products/harmonic/PARAMETERS.md, and the topology decision is ADR 0007.

Sequence S-01

Sequence is a monophonic programmed-current synthesizer with a directly visible 16-step host-synchronised program. Each step owns note offset, gate, accent, and slide. MIDI plays the voice while stopped and transposes the pattern while the host runs.

Its original voice combines two anti-aliased oscillators and a sub oscillator, a saw–pulse–sine wave path, pulse-width control, a bounded driven mixer, and one nonlinear four-stage filter whose Weight control moves continuously between its two- and four-pole outputs. This shared-state topology avoids the level and phase hollowing of parallel-filter crossfades. Pressure coordinates mixer drive, filter-envelope depth, accent gain, and filter loading. It is topology-informed, not an emulation of a named synthesizer.

The full internal-beta contract is docs/products/sequence/SPECIFICATION.md.

Loop L-01

Loop catches mono or stereo audio on three preallocated tape decks. RELOOP prints the currently transformed playback through a record/reproduce stage onto the next deck, allowing pitch, reverse, splice, transport motion, loading, and loss to accumulate across generations. The latest three generations remain navigable while the generation counter continues. Host-synced beat length and free seconds remain separate stable parameters; MIDI performance actions are sample-offset accurate.

The prototype reports zero latency and never allocates or locks while processing. Its schema-2 control state and schema-1 migration are deterministic, but captured audio and generations are not yet serialized; session memory recall remains a stated release blocker. See docs/products/loop/SPECIFICATION.md.

Impulse I-01

Impulse synthesizes eight objects—Kick, Click, Burst, Body, Low, Crack, Metal, and Cut—from exciters, resonant bodies, and bounded amplifier stages. Every track owns an always-visible 32-step Off/Hit/Accent row with an independent 1–32-step cycle, probability, ratchets, timing, condition, and accent. Pulses and Rotation are an explicit pattern generator, never a hidden playback source. Stored seeds make probability, variation, and mutation reproducible from host PPQ across block partitions and project recall. MIDI pitch classes C through G trigger the eight objects directly.

The default polymetric lengths remain host-clocked while drifting against one another. No drum samples, genre kits, named circuit clone, or nondeterministic “analog” behavior defines the product. See docs/products/impulse/SPECIFICATION.md.

Field F-01

Field is a heavy reverb conceived as stored spatial energy rather than a room simulation. Its eight moving feedback lines, deterministic grain motion, and two internal dual-head pitch voices form one recirculating instrument. Audio or sample-offset MIDI notes can excite the field. The large FOREVER control smoothly holds and animates its memory; press it again to release back into the Mass-controlled decay.

Mass, Grain, Pitch, Motion, Distance, Blend, and Output remain on one panel. There is no IR, named room, hidden quality page, decorative animation, nondeterministic drift, or hardware-emulation claim. Field reports zero latency and its live audio memory intentionally starts empty after session reload. See docs/products/field/SPECIFICATION.md.

Requirements

The tested development environment is macOS on Apple Silicon, with x86_64 builds executed under Rosetta. You need:

• CMake 3.25 or newer;
• a C++20 compiler;
• Git;
• Python 3 for documentation and build-metadata checks;
• internet access when configuring the optional VST3 build, which fetches the pinned JUCE source.

The framework-independent DSP and lab build without JUCE or network access. The VST3 build uses JUCE 8.0.13 at the product boundary; the DSP core contains no JUCE headers.

Build and test

DSP core and laboratory

This is the fastest build and the right starting point for algorithm work:

cmake -S . -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build --parallel
ctest --test-dir build --output-on-failure

It builds:

• density_dsp — framework-independent production DSP;
• density_tests — core correctness and property checks;
• density_lab — offline rendering, measurement, comparison, and listening-pack generator;
• harmonic_dsp and harmonic_tests — independent four-band production DSP and its correctness/property checks;
• harmonic_lab — candidate research, six-rate product reports, and the production-graph benchmark.
• sequence_dsp and sequence_tests — independent MIDI voice, host-clocked step program, filters, and correctness properties.
• sequence_lab — deterministic host-clocked render and worst-case voice benchmark.
• loop_dsp, loop_tests, and loop_lab — capture/playback memory engine, property tests, deterministic render, and worst-case benchmark.
• impulse_dsp, impulse_tests, and impulse_lab — physical-event voices, deterministic polymetric scheduling, render, and benchmark.
• field_dsp, field_tests, and field_lab — stored-energy field, grain and pitch feedback, six-rate report, and worst-case benchmark.

VST3, adapter tests, and standalone host

The VST3 build is opt-in because it fetches licensed JUCE source:

cmake -S . -B build-plugin \
  -DASTE_BUILD_VST3=ON \
  -DCMAKE_BUILD_TYPE=Release
cmake --build build-plugin --parallel
ctest --test-dir build-plugin --output-on-failure

The plugin bundles are produced at:

build-plugin/DensityD01_artefacts/Release/VST3/Density D-01.vst3
build-plugin/HarmonicH01_artefacts/Release/VST3/Harmonic H-01.vst3
build-plugin/SequenceS01_artefacts/Release/VST3/Sequence S-01.vst3
build-plugin/LoopL01_artefacts/Release/VST3/Loop L-01.vst3
build-plugin/ImpulseI01_artefacts/Release/VST3/Impulse I-01.vst3
build-plugin/FieldF01_artefacts/Release/VST3/Field F-01.vst3

Each product has direct JUCE-adapter tests. The separate vst3_smoke_host links no product adapter or DSP; it discovers and loads each built bundle through the actual VST3 ABI, restores state, and processes irregular blocks.

To run that smoke host directly:

"build-plugin/vst3_smoke_host_artefacts/Release/vst3_smoke_host" \
  "build-plugin/HarmonicH01_artefacts/Release/VST3/Harmonic H-01.vst3" \
  "Harmonic H-01" "Harmonic" 12

Sanitizers

AddressSanitizer and UndefinedBehaviorSanitizer are intended for tests, not a distributable plugin:

cmake -S . -B build-sanitize \
  -DASTE_BUILD_VST3=ON \
  -DASTE_SANITIZERS=ON \
  -DCMAKE_BUILD_TYPE=Debug
cmake --build build-sanitize --parallel
ctest --test-dir build-sanitize --output-on-failure

Universal macOS bundle

cmake -S . -B build-plugin-universal \
  -DASTE_BUILD_VST3=ON \
  -DCMAKE_BUILD_TYPE=Release \
  '-DCMAKE_OSX_ARCHITECTURES=arm64;x86_64'
cmake --build build-plugin-universal --parallel
ctest --test-dir build-plugin-universal --output-on-failure

The internal bundle receives an ad-hoc signature so its completed manifest and binary can be validated locally. It is not Developer ID signed or notarized.

Build and install all instruments on a music Mac

Clone the repository on the music machine, quit Cubase and Ableton, then run:

./tools/build_and_install_macos.sh

The script builds and tests universal arm64+x86_64 bundles, verifies both architectures and signatures, and installs the complete six-product line under ~/Library/Audio/Plug-Ins/VST3. Existing copies are preserved as timestamped backups, and no sudo is used. Reopen the DAW and rescan VST3 plugins.

These are ad-hoc-signed, unnotarized internal builds with deliberately invalid placeholder bundle identifiers. macOS may require locally allowing the bundle; they are for private host and musical validation, not distribution.

For the plain transfer-folder workflow, see INSTALL_MACOS.md.

When all six bundles and INSTALL_ALL.command are in one transfer folder, quit every audio host and double-click the command, or run:

./INSTALL_ALL.command

It installs and locally allows every bundle without sudo, preserving any previous versions as timestamped backups.

An explicit bundle path may be supplied when testing another build:

./tools/install_density_macos.sh \
  "build-plugin-universal/DensityD01_artefacts/Release/VST3/Density D-01.vst3"
./tools/install_harmonic_macos.sh \
  "build-plugin-universal/HarmonicH01_artefacts/Release/VST3/Harmonic H-01.vst3"
./tools/install_sequence_macos.sh \
  "build-plugin-universal/SequenceS01_artefacts/Release/VST3/Sequence S-01.vst3"
./tools/install_loop_macos.sh \
  "build-plugin-universal/LoopL01_artefacts/Release/VST3/Loop L-01.vst3"
./tools/install_impulse_macos.sh \
  "build-plugin-universal/ImpulseI01_artefacts/Release/VST3/Impulse I-01.vst3"
./tools/install_field_macos.sh \
  "build-plugin-universal/FieldF01_artefacts/Release/VST3/Field F-01.vst3"

Internal packaging rehearsal

After building the universal tree, create and inspect the deterministic internal archive with:

cmake --build build-plugin-universal --target density_package
python3 tools/package_density.py verify \
  --archive build-plugin-universal/packages/Density-D01-0.1.0-internal-macos-universal.zip

The archive is explicitly marked internal-development-only. It is ad-hoc signed, uses the placeholder bundle identity, is not notarized, and must not be distributed. It includes a deterministic SPDX 2.3 SBOM for Density, pinned JUCE, JUCE's bundled VST3 SDK, and the exact reviewed dependency-security ledger. PACKAGE.json binds the ledger's SHA-256, review date, expiry, and disposition; normal inspection rejects expired or altered evidence. The format decisions are ADR 0004 and ADR 0005.

The packaged dependency pins also have a dated, expiring advisory review:

python3 tools/check_dependency_security.py \
  docs/security/dependency-audit.json .

The check is offline and runs under CTest. Its evidence sources and limits are defined by ADR 0006.

DSP laboratory

density_lab generates its own deterministic signals, renders WAV/CSV output, benchmarks production code, compares detector and oversampling candidates, and creates blinded listening packs without opening a DAW.

Common entry points:

Area	Commands
Basic render and CPU	./build/density_lab [output.csv], --benchmark
Production regression	--golden, --production-consistency
Detector research	--detector-compare, --detector-auditions, --detector-blind
Nonlinear behaviour	--alias-report
Oversampling research	--oversampling-report, --oversampling-prototype, --halfband-prototype, --kaiser-prototype, --kaiser-sweep, --kaiser-rate-sweep, --kaiser-linear-report, --kaiser-length-report, --kaiser-finalist-report, --oversampled-chain-report
Automation and smoothing	--automation-report, --output-smoothing-report, --drive-smoothing-report, --attack-smoothing-report, --blend-smoothing-report
Musical evaluation	--oversampling-auditions, --automation-auditions, --stereo-stability-auditions, --density-macro-auditions
Stereo analysis	--stereo-stability-report

Most report modes accept an optional output file or directory after the flag. CTest invokes every deterministic report with known paths. Measurement methods, tolerances, and the meaning of each output column live in TESTING.md; algorithm decisions and rejected candidates live in docs/products/density/DSP_RESEARCH.md.

Engineering guarantees and evidence

The repository treats testing as part of the DSP architecture rather than a release-week activity.

Current automated coverage includes:

• finite output under silence, non-finite/extreme input, abrupt automation, and malformed state;
• 44.1, 48, 88.2, 96, 176.4, and 192 kHz;
• zero-length blocks plus block sizes 1, 2, 7, 16, 32, 64, 127, 128, 256, 511, 512, 1024, and 2048;
• mono and stereo layouts, linked/independent detection, bypass, repeated prepare/process/release, and variable block partitioning;
• exact dry-path preservation and measured/reported zero latency;
• 3,072 deterministic malformed-state cases;
• deterministic golden renders with metric tolerances rather than brittle audio hashes alone;
• global allocation counting across the core and JUCE adapter;
• calibrated macOS interposition checks for callback locks, file access, and direct writes;
• arm64 Release, arm64 ASan/UBSan, and x86_64 Release test trees;
• semantic state exchange between arm64 and x86_64 hosts.

The plugin test tree runs the complete deterministic CTest suite. Independent local validation has passed pluginval 1.0.4 at strictness 10 and the Steinberg VST3 SDK 3.8.0 extensive suite at 537/537. Density has arm64 and Rosetta x86_64 validator history; Harmonic's current universal beta has arm64 validator evidence and separate two-slice/ABI verification. Sequence has direct core, adapter, and repository ABI-host evidence; independent validator and DAW runs remain next. The exact run history is in HOST_COMPATIBILITY.md.

GitHub Actions builds the core on arm64 and Intel runners, builds a universal VST3, verifies its architectures and ad-hoc signature, and runs an arm64 sanitizer tree. It also builds the pinned official Steinberg validator from source and requires its extensive suite to pass the signed bundle. The workflow is .github/workflows/ci.yml.

Real-time rules

All production processors expose noexcept processing. Processing may not allocate, free, lock, wait, log, access files or networks, resize containers, trigger lazy initialization, call blocking OS services, or throw through the callback. Buffers and mutable DSP state are prepared in advance. Non-finite input is sanitized and output must remain finite. Thread ownership and the limits of the runtime audit are documented in REALTIME_SAFETY.md.

State

Each product uses its own portable, versioned XML state document containing stable parameter IDs and scalar values. Unknown parameters are ignored, missing parameters receive defaults, duplicate IDs are rejected, and malformed state leaves the current configuration unchanged. See STATE_FORMAT.md.

Performance

The current production graph measured a 0.283874% median of one M4 Pro performance core at 48 kHz / 128 samples under worst-case block-rate automation. This is comfortably below the provisional 1% target on that machine, but it is not evidence for the oldest supported Apple Silicon or a native Intel Mac. Full measurements and rejected oversampling budgets are in PERFORMANCE_BUDGETS.md.

Harmonic measured 0.718134% on the same class of machine at 48 kHz / 128 samples while every band and its macro changed each block. This passes the local provisional 1% budget, but still requires older Apple Silicon and native Intel evidence.

Sequence measured 0.292424% on the same machine at 48 kHz / 127 samples with Pressure at 100%, resonance at 85%, the shared-state character filter active, and stereo output. It passes the local provisional 1% budget; native Intel, older Apple Silicon, and DAW/UI-open measurements remain external gates.

Loop's generational topology measured a 0.526622% five-run median on the same machine at 48 kHz / 127 samples while continuously printing through pitch, transport modulation, Record, and Loss at worst case. It passes the local provisional 1% budget; captured-memory recall, native Intel, older Apple Silicon, and DAW/UI-open measurements remain open.

Impulse measured a 1.26032% five-run median on the same machine at 48 kHz / 127 samples with all eight objects and every visible pattern cell active, 4× ratchets, 180 BPM, maximum Energy, Variation, Mutation, and Drive. It passes its 2% eight-object stress budget; native Intel, older Apple Silicon, DAW, and open-UI evidence remain external.

Field's five-run worst-case Release benchmark measured a 0.320727% median of one M4 Pro performance core at 48 kHz / 127 samples with FOREVER, Mass, Grain, Pitch, Motion, Distance, and Blend at maximum. Its fixed processing state is 1,180,056 bytes, below the product-specific 1.5 MiB budget. Native Intel, oldest-supported Apple Silicon, loaded-DAW, long-held-energy, and open-UI measurements remain external.

Current release status

The six-product line consists of internal prototypes, not releases. Density has repository evidence for 16 of its 25 release gates. Harmonic has the engineering boundary needed for first external tests; all six still require people, DAWs, and target hardware for:

• Cubase 14, Ableton Live 13/beta, and one additional real-host matrix;
• real-time versus offline bounce, freeze, reopen, suspend, and crash-recovery checks;
• native Intel and oldest-supported Apple Silicon performance;
• Retina host rendering, VoiceOver, keyboard navigation, and independent first-use observation;
• completed blind automation, Density, stereo-link, detector, and oversampling listening sheets;
• ten real musical projects across mastering, ambient, percussion, bass-heavy, and sparse material;
• final signing, notarization, packaging, identity, and licensing review.

The authoritative ledger is RELEASE_CHECKLIST.md, and the next permitted work is in ROADMAP.md. Do not turn a green build into a compatibility or fidelity claim.

Architecture

density_dsp  <- density_tests  <- density_lab
      ^
      +------ Density JUCE adapter/UI <- density_plugin_tests

harmonic_dsp <- harmonic_tests <- harmonic_lab
      ^
      +------ Harmonic JUCE adapter/UI <- harmonic_plugin_tests

sequence_dsp <- sequence_tests
      ^
      +------ Sequence JUCE instrument/UI <- sequence_plugin_tests

loop_dsp     <- loop_tests <- loop_lab
      ^
      +------ Loop JUCE effect/UI <- loop_plugin_tests

impulse_dsp  <- impulse_tests <- impulse_lab
      ^
      +------ Impulse JUCE instrument/UI <- impulse_plugin_tests

field_dsp    <- field_tests <- field_lab
      ^
      +------ Field JUCE effect/UI <- field_plugin_tests

all VST3 bundles <- vst3_smoke_host (dynamic ABI load only)

The production DSP is ordinary C++20. JUCE is restricted to the VST3, host, state-adapter, and UI boundary. Product DSP does not depend on widgets, and serialized state does not depend on widget layouts. The accepted framework decision is ADR 0001; the fixed zero-latency quality decision is ADR 0002; and the independent validation boundary is ADR 0003; and the internal-only package boundary is ADR 0004. The package dependency boundary is ADR 0005. The expiring dependency-security review is ADR 0006. Field's fixed stored-energy topology and memory exception are ADR 0015.

Repository map

apps/
  density/             production DSP, JUCE adapter, and editor
  harmonic/            independent four-band DSP, adapter, and editor
  sequence/            monophonic voice, host sequencer, adapter, and editor
  loop/                capture memory, adapter, and editor
  impulse/             rhythmic objects, polymetric clock, adapter, and editor
  field/               moving feedback field, pitch memory, adapter, and editor
  dsp-lab/             offline renderer and measurement laboratory
  standalone-host/     minimal headless VST3 smoke host
docs/
  adr/                 accepted engineering decisions
  products/density/    cycle reports and Density research evidence
  products/harmonic/   Harmonic contract, research, and test handoff
  products/field/      Field contract, state, cycle evidence, and test handoff
  research/            lawful historical-reference metadata
  testing/             listening protocols
tests/
  golden/              reviewed production metrics
  density_tests.cpp    framework-independent tests
  density_plugin_tests.cpp
  harmonic_tests.cpp
  harmonic_plugin_tests.cpp
  sequence_tests.cpp / sequence_plugin_tests.cpp
  loop_tests.cpp / loop_plugin_tests.cpp
  impulse_tests.cpp / impulse_plugin_tests.cpp
  field_tests.cpp / field_plugin_tests.cpp
  realtime_audit_mac.cpp
tools/                  repository-policy and provenance checks

The repo deliberately does not contain a speculative universal audio framework, empty libraries for future products, or direct product-to-product dependencies.

Research and claims

Historical compressor, limiter, amplifier, and clipping circuits are studied for engineering ideas such as headroom, loading, time constants, feedback, recovery, and overload behaviour. The project does not redistribute service manuals with unclear rights, copy proprietary firmware, or present schematic study as measured hardware emulation.

Research metadata and access status are recorded in docs/research/schematics/catalog.yaml. The policy is in SCHEMATIC_RESEARCH.md, and the broader measurement standard is in DSP_RESEARCH.md.

Documentation index

Document	Purpose
ARCHITECTURE.md	Product boundaries, signal graph, and ownership
docs/PRODUCT_PHILOSOPHY.md	Family character and design principles
PARAMETER_MODEL.md	Stable IDs, ranges, defaults, mappings, and smoothing
STATE_FORMAT.md	Schema, validation, and state guarantees
REALTIME_SAFETY.md	Audio-thread policy and runtime audits
TESTING.md	Test layers, lab protocols, and measurement tolerances
HOST_COMPATIBILITY.md	Validator and host evidence
PERFORMANCE_BUDGETS.md	CPU, memory, latency, and UI budgets
UI_SYSTEM.md	Shared visual and interaction language
RELEASE_CHECKLIST.md	All 25 Density release gates
SPECIFICATION_STATUS.md	Master-brief requirements mapped to evidence, decisions, and external gates
ROADMAP.md	Current sequencing and explicit deferrals
RESEARCH_LOG.md	Research chronology
CONTRIBUTING.md	Change requirements
SECURITY.md	Prototype security reporting policy

Each substantial engineering cycle records what changed, why, evidence, risks, and the smallest next action in its product documentation directory.

Contributing

Changes should identify a concrete musical or engineering failure, preserve the DSP/UI/state boundaries, add the smallest deterministic regression check, and include before/after measurements for DSP work. Golden data is never updated automatically. Read CONTRIBUTING.md before opening a change.

Licensing and distribution

No project-wide distribution licence has been selected, so this repository is not itself permission to redistribute source or binaries.

The opt-in VST3 build fetches JUCE 8.0.13. JUCE is available under its EULA or AGPLv3; a closed-source distributable requires the applicable JUCE licence and reviewed notices. No third-party manuals, firmware, impulse responses, samples, or commercial plugin code are included. See THIRD_PARTY_NOTICES.md and LICENSES/README.md.

Do not distribute a plugin build until the company identity, project licence, JUCE licence, signing identity, notarization, package contents, and release gates have all been reviewed.