|LADSPA (Linux Audio Developers Simple Plugin API) is an audio plug-in standard originally developed on Linux, but which can be ported to Windows and Mac too. Audacity has built-in support for LADSPA plug-ins.
Writing LADPSA plug-ins
Audacity behaves as an excellent LADSPA host. Just read up about LADSPA, and make your plug-ins correctly. As a starting point, look at the LADSPA developers' documentation and the LADSPA site's example plug-ins. Keep in mind that Audacity "runs" the plug-in multiple times with some specific number of samples. So, don't assume that your plug-in will get the entire selection the first time. Here is an example LADSPA plug-in made by a user for plotting frequency variation.
Using LADSPA plug-ins
Nothing special is needed for using LADSPA plug-ins for Audacity on Linux. It's usually most convenient to place your LADSPA plug-ins in one of the following:
- any colon-delimited path specified by the LADSPA_PATH environment variable.
In addition LADSPA plug-ins installed using the package manager will frequently be installed in:
Note that if building Audacity from the source code, these paths will not be seen by Audacity unless there is some other mechanism to direct Audacity to look there, for example:
- Audacity is configured to install in /usr/
- /usr/lib/ladspa or /usr/lib64/ladspa are added to the LADSPA_PATH environment variable. (See here for information regarding the LADSPA_PATH environment variable).
Restart Audacity and the plug-ins should be in themenu, underneath the divider.
If you have the ladspa-sdk installed, you can run listplugins from a terminal to list all plug-ins in your LADSPA_PATH.
Windows and Mac OS
Audacity also supports LADSPA plug-ins on Windows and Mac OS. Any LADSPA plug-in compiled as a Windows .dll or Mac .dylib shared library will work on these platforms. An extensive set of LADSPA plug-ins is available for Windows and Mac OS X.
To add LADSPA plug-ins to Audacity, place them in the Plug-Ins folder inside the Audacity installation folder. Restart Audacity and the plug-ins should be in the C:\Program Files on Windows, or under Mac Hard Disk > Applications on OS X.menu, underneath the divider. The Audacity installation folder is usually under
As on Linux, Audacity will also detect LADSPA plug-ins if you put them in a folder specified in the LADSPA_PATH environment variable.