VST Plug-ins
Audacity can load VST effects (but not VST instruments) on
all operating systems. The VST Enabler is no longer
required. Install the VST effects to the Audacity Plug-Ins
folder on Windows, to ~/Library/Application
Support/audacity/Plug-Ins on OS X/macOS or to system
locations. Then use the Plug-ins Manager to enable the
new plug-ins as in the plug-in installation instructions
above.
The VST Plug-ins page
on the Audacity Wiki contains further
help for VST plug-ins, and lists a large number of VST
plug-ins that have been reported to work well in Audacity.
Audio Unit Plug-ins
On Mac OS X only, you can add Audio Unit plug-ins
to the system
plug-in directories (Audacity will not recognize any
Audio Units in its own “plug-ins” folder). Then use the
Plug-ins Manager to enable the new plug-ins and any required
Apple Audio Units as in the plug-in installation
instructions above.
Module Plug-ins
Experimental modules offer
a further way to extend Audacity with new features.
LADSPA Plug-ins
LADSPA is superseded by LV2. These plug-ins are mostly built
for Linux, but some old LADSPA plug-ins are available via
the Legacy Windows and Legacy Mac sections.
Libraries
The LAME
MP3 encoding library allows Audacity to export audio
in the popular MP3 format. LAME is now
bundled in with the latest Audacity version.
The FFmpeg
import/export library allows Audacity to import and
export many additional audio formats such as AC3,
AMR(NB), M4A and WMA, and to import audio from video
files. Audacity 2.0.6 and later requires FFmpeg 1.2 to
2.3.x (or libav 0.8 to 0.10.x).