cardinal: cardinal (Open-source VCV Rack) cardinal: cardinal: Cardinal is a free and open-source virtual modular synthesizer plugin, cardinal: available as CLAP, LV2, VST2 and VST3 audio plugin for FreeBSD, Linux, cardinal: macOS and Windows. Plus AU and JACK or Native audio standalone for cardinal: some systems. It is based on the popular VCV Rack but with a focus on cardinal: being a fully self-contained plugin version. cardinal: cardinal: cardinal: cardinal: