this make me understand more how things worked together in Ardour and plugins use ! Maybe in 1 or 2 centuries I’ll be a true hacker !! (this for smile, it’s not my goal, but anyway, fun to know what you do, and why))
Now, what you said make me have a question :
in most builds made these last days (try to custom a Debian system for music) have add --prefix=/usr to ./configure, cause read somewhere it was fine… Did I do wrong ??? I means, except for plugins, thus are not build yet, I thought it was better to do that after Ardour.
Or, said in another way : can it be done to add directory where I build to PATH, which is a concept I don’t really get yet ?
If you build them yourself and, don’t change the install path, they should install to /usr/local/lib/ladspa and /usr/local/lib/lv2 respectively, and that’s where Ardour looks for them so restarting Ardour should update the list.
If you install to some other place you either have to make symbolic links to those directories (perhaps using ‘stow’) or start a terminal and run export LADSPA_PATH=/path/to/your/ladspa/plugins ; export LV2_PATH=/path/to/your/lv2/plugins ; ardour2
Plugins are located based on the LADSPA_PATH environment variable pointing to the appropriate directory, or by looking in (few) expected places. In most cases if you install plugins through the distribution manager, it should take care of that, but obviously I can’t guarantee this in all cases.