BLACKBOX

A polyphonic subtractive synthesizer plugin (VST3) for FL Studio and other hosts.

Architecture

The DSP core in src/dsp/ is header-only, dependency-free C++17 with no JUCE types in it. That is deliberate: it means the engine can be compiled and regression-tested on any machine with a compiler, with no GUI libraries, no audio device and no DAW. src/plugin/ is the JUCE layer that wraps it.

src/dsp/        engine - oscillators, filter, envelopes, LFOs, FX
src/plugin/     JUCE wrapper - parameters, processor, editor, look and feel
tools/render.cpp  offline renderer: drives the engine, writes a WAV

Features

• Two oscillators (saw / square / triangle / sine / noise, PolyBLEP anti-aliased) plus a sub oscillator and a noise source, with optional osc 2 hard sync
• Up to 8-voice unison per note with detune and stereo spread
• TPT state-variable filter (LP / BP / HP / notch) with resonance, drive, envelope amount and key tracking
• Two ADSR envelopes and two LFOs (sine / tri / saw / square / S&H), each LFO with a fixed destination - LFO 1 vibrato, LFO 2 filter sweep - and a depth control; the mod wheel adds to vibrato depth on top of the panel setting
• Chorus, stereo delay and reverb, each its own section of the effects rack
• 16-voice polyphony with release-priority voice stealing, glide, pitch bend

Building

Windows VST3 is built by CI on every push - see .github/workflows/build.yml. Download the BLACKBOX-windows artifact and copy BLACKBOX.vst3 into C:\Program Files\Common Files\VST3. The same artifact contains a standalone BLACKBOX.exe, which needs no host at all.

Locally, the DSP core builds anywhere:

cmake -B build -DBLACKBOX_BUILD_PLUGIN=OFF
cmake --build build --target bb_render
./build/bb_render out.wav

The full plugin build additionally needs JUCE's dependencies. On Debian/Ubuntu:

sudo apt install -y libasound2-dev libx11-dev libxext-dev libxrandr-dev \
  libxinerama-dev libxcursor-dev libfreetype6-dev libfontconfig1-dev \
  libgl1-mesa-dev pkg-config

cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build --parallel

Licence

GPLv3, per the JUCE open-source licence this is built under.