I reported to the LinuxSampler devs as you suggested. They have already fixed another issue I reported in the same email, but replied with the following about the VST links. Here’s a link to mailing list archive: https://sourceforge.net/p/linuxsampler/mailman/linuxsampler-devel/?style=flat&viewmonth=201905
So like I expcted, the stand-alone app runs there. Then the problem you have
with the LS VST not launching in Ardour is indeed very likely caused by a
conflicting libstdc++ version.
Background: we are currently still using GCC as compiler on our build server
for compiling the daily snapshot installers for Windows. And I am pretty sure
your Ardour binary was compiled with clang. The two compilers use their own
implementation of libstdc++, and both cannot be loaded into one process at the
Like already suggested in the Ardour forum, one workaround would be if we
statically link libstdc++ into our binaries (instead of letting our binaries
load libstdc++ dynamically as DLL on startup like it is now). But that is
tricky and may introduce new problems, since all libs used must then use our
statically linked libstdc++ instead.
Another option would be if we just switch to clang for compiling the Windows
installer. But then it would cause other DAWs getting the same VST issue if
they were compiled with GCC instead.
IMO the best solution on long term would be Ardour running VST plugins in
their own process, instead of loading VST plugins directly into the Ardour
process. That way libs loaded by VST plugins would no longer conflict with libs
of other plugins or host app (i.e. Ardour). Because even if we do some of the
workarounds mentioned above, the next issue would already be ahead: e.g. if
you want to edit a gig file currently being played back as VST instrument in
Ardour, then our gigedit instrument editor would try to load Gtk3 libs, and
Ardour already loaded Gtk2 libs, hence gigedit would never show up on your
I know the opinion of Ardour developers is that running plugins in their own
process would be inefficient due to expensive context switches, but other DAW
apps like Logic already switched to that new model and performance seems to be
Ok nowadays. In the end this could also become an optional setting per plugin
on Ardour side.