VST3 and AU
Live's stock devices are great, but a few jobs go faster with a dedicated plugin: a finished vocal sound, real tape character and lush shimmer. Every plugin here loads in Live 11 and 12 on Mac and Windows as VST3, and as AU on macOS.
The real plugin engine, running in your browser: same DSP code and presets as the VST3/AU/AAX.
/Library/Audio/Plug-Ins/VST3/Library/Audio/Plug-Ins/ComponentsC:\Program Files\Common Files\VST3Installing and using plugins in Ableton Live.
Both. On Windows Live loads VST2 and VST3. On macOS it also loads Audio Units. If a plugin offers VST3, use that.
Yes. Every edition of Live 11 and 12 supports third-party VST3 and AU plugins.
Yes. Pump (sidechain volume shaper) and Spread (stereo widener) are free and work in any version of Live.
Any VST3 instrument on Windows or macOS, and Audio Units on a Mac. Live also includes its own instruments, such as Simpler, Sampler, Drum Rack, Operator and Wavetable, depending on your edition. Ours are Hydra (hybrid synth), Nova (synth), Thump (drum machine) and the free Keys electric piano: drop any of them on a MIDI track.