Failed to install an LV2 plugin

Hello,

Today I installed the LV2 plugin

General MIDI Synth

downloading the file x42-gmsynth-v0.6.0-x86_64.tar.gz from the web page x42 General MIDI Synth. I followed the installation indications contained in the README.txt file, installing (better said: copying) the plugin directory to $HOME/.lv2.
After that, I made a re-scan.

Result:
in the Plugin Manager I only see the plugin previously installed probably during the Ardour installation:
Info of the plugin: Bundle: file:///opt/Ardour-8.2.0/lib/LV2/gmsynth.lv2/.

Can somebody please explain why the plugin I installed is not visible?

Remark: as I installed the plugin, I didn’t know that this one had already been installed.

Regards.

A common mistake is to copy the files and not the bundle folder. Do you have the dir:
~/.lv2/gmsynth.lv2/ ?

If the plugin is already installed, Ardour (here really liblilv) automatically picks one one with the higher version number. You will not find the same plugin twice.

LV2 plugins do not require scanning. They directly provide meta-data to the DAW.
LV2 plugins are automatically and unconditionally discovered at application start.

Restart Ardour to pick up newly instaled LV2 plugins.

Hello Robin,
I copied the bundle folder, not the files: the path is exactly what you wrote in your answer.
Restarting Ardour didn’t help.

In https://manual.ardour.org/working-with-plugins/getting-plugins/, Section How to install plugins? it is stated:
LV2 plugins are folders/directories. They need to be installed in either /usr/lib/lv2, /usr/local/lib/lv2 or a directory mentioned in the local LV2_PATH environment variable.
No … /.LV2/ directory is mentioned here.
My system does not seem to have a LV2_PATH environment variable.
It is confusing for me.
:confused:
… any explanation?

That is perfectly fine and the normal case.
The env variable is only needed to override the default install locations (which is discouraged).

The canonical documentation is Filesystem Hierarchy Standard

I do not want to stress your patience but

  • why is the $HOME/.lv2 not mentioned in the own Ardour manual? (yes, I know, I should ask the Ardour people, not you, but I think maybe you know the background for this discrepancy).

  • does Ardour know $HOME/.lv2 to look for plugins there?

These things are not controlled by Ardour, but by the standard LV2 libraries that programs use in order to host LV2 plugins. The same libraries that are used by, for example, the command lv2ls which when run in a terminal window will list all LV2 plugins that are “known” on your system.

Hi Paul,
the command lv2ls is not contained in my system. The terminal says “install lilv-utils”. I did it, but the command still does not exist.
In the man pages from Arch Linux I read: lv2ls is a part of lilv, by David Robillard.
The library lilv is installed in my system.

Do you have an idea how to bring lv2ls in my system to work?
Cheers!

Hello Paul,
please ignore my question, now the command lv2ls works, I guess I made somehow an error during my first attempt to install the library.

lv2ls is a very useful command, thank you for the hint!
Cheers