Ladspa Plug-ins

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.

Related article(s): Nyquist Plug-ins VST Plug-ins Other pages in our Plug-ins category

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

Linux

Nothing special is needed for using LADSPA plug-ins for Audacity on Linux. It's usually most convenient to place your LADSPA plugsin in:

• /usr/lib/ladspa
• /usr/local/lib/ladspa
• $LIBDIR/ladspa
• $INSTALL_PREFIX/ladspa
• any colon-delimited path specified by the LADSPA_PATH environment variable

Then restart Audacity and the plug-ins should be in the Effect menu, 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.

Advanced users on Linux can compile the latest Audacity Beta development code and enable experimental support for LV2. This is an extensible, "second-generation" version of LADSPA that has a wider range of effects, can use LV2 synthesizer plug-ins as powerful tone generators, and supports effect categorisation.

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 Effect menu, underneath the divider. The Audacity installation folder is usually under C:\Program Files on Windows, or under Mac Hard Disk > Applications on OS X.

As on Linux, Audacity will also detect LADSPA plug-ins if you put them in a folder specified in the LADSPA_PATH environment variable.