Five-A MultiFX Processor

A guitar multi-effect plugin whose architecture and workflow are modelled on an early-1990s guitar multi-effect floor unit, referred to here as "the original unit".

Status: Milestone 3 done. VST3 and (on macOS) Audio Unit plugins with the original unit's five-effect chain (compressor, distortion/overdrive, 3-band EQ, chorus/flanger, reverb/delay), noise reduction and master volume, each control with its original steps. 30 programs in six banks: bank 1 is yours to write; banks 2–6 hold development presets ("DEV …") and the one factory program the original's manual documents. Every algorithm is a placeholder: the controls and their documented values match the original, the sound does not claim to. The editor is a replica of the original's front panel, in both its Program and Manual/Edit modes. A Processing Rate setting runs the effects at the host's rate or at the original's 44.1 kHz (the same rate, not a model of its converters). See docs/implementation-plan.md for the roadmap and docs/evidence-register.md for what is known versus assumed.

Requirements

• CMake 3.25 or newer, and Ninja (recommended)
• A C++20 compiler: Xcode 15+ / Apple Clang, Visual Studio 2022, or GCC 11+ / Clang 15+
• Linux only: the JUCE system packages listed in .github/workflows/build.yml

Build and test

JUCE 9.0.2 and Catch2 v3.9.1 are git submodules in external/, pinned to their release tags. Clone with them:

git clone --recurse-submodules https://github.com/CatastrophicCoder/90sGuitarMultiFx.git
# or, in an existing clone:
git submodule update --init

cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=Release
cmake --build build
ctest --test-dir build --output-on-failure

Built products land in build/FiveAPlugin_artefacts/<config>/:

Format	Path
VST3	VST3/Five-A MultiFX Processor.vst3
AU (macOS)	AU/Five-A MultiFX Processor.component

A Release build also installs the AU and VST3 into your user plugin folders (~/Library/Audio/Plug-Ins on macOS); a Debug build does not. Override with -DFIVEA_COPY_PLUGIN=ON or OFF. To build without tests, -DFIVEA_BUILD_TESTS=OFF.

Validating the plugin (macOS)

auval -v aufx Nmf1 Ctcd     # the installed AU, i.e. the last Release build
/Applications/pluginval.app/Contents/MacOS/pluginval --strictness-level 10 \
    --validate "build/FiveAPlugin_artefacts/Release/VST3/Five-A MultiFX Processor.vst3"

Formatting

CI checks formatting with clang-format 18.1.8:

pipx install clang-format==18.1.8
clang-format -i $(git ls-files 'src/*.h' 'src/*.cpp' 'tests/*.h' 'tests/*.cpp')

Layout

Path	Contents
external	JUCE and Catch2 submodules, pinned to release tags
src/core	Engine façade (FiveAProcessor, pure C++), parameter IDs, parameter layout and state (JUCE)
src/dsp	DSP building blocks (only gain smoothing so far)
src/plugin	JUCE AudioProcessor and editor
src/ui	The replica panel: layout, look-and-feel, controls, LED display
resources/fonts	Barlow Condensed (SIL OFL), embedded in the plugin, with its licence
tests/Unit	Engine tests, no JUCE
tests/Integration	Plugin tests through the AudioProcessor API
docs	Architecture, evidence and source registers, parameter specification, validation plan

Licence

GNU Affero General Public License v3.0; see LICENSE. Third-party components and their licences are listed in THIRD_PARTY_NOTICES.md.