Weird PlugIn Dialogs, When will they be fixed?


I’m lovin’ the new 2.5 release, but I was under the impression that one of the fixes was going to be the mono/stereo plug-in routing. I am using Ardour with VST and it’s a real PITA to have to insert an M/S splitter on mono tracks to use many of the effects (also many of the LADSPA ones as well). This is not really a criticism but I would be very curious to know which “future” version of Ardour that this will be addressed in. I’ve got a Rabid Cubase fan of a bandmate that’s looking over my shoulder all the time in our latest recordings that I’ve insisted we use Ardour on. When things like "Weird Plug-in Dialogs pop up I can see his slow head shake of disapproval out of the corner of my eye!

Just curious, Thanks

I was under the impression that these were fixed. Several people that had problems with them and who were on IRC confirmed that the problem had gone away for them. What precisely is the issue (and message) you are getting?


Your quick reply and accessibility to users is greatly appreciated!

DELL LAPTOP 2.0ghz Core Duo
Tascam US-122
Ubuntu 7.10 w/rt Kernel
JACK 0.109.2 (Ema-Tech Package)
Ardour 2.5 w/VST (Source Stable tarball not SVN)

I have a new session, I import a MONO track, When I try to insert any VST Plug-in (including plugins set to MONO) pre-fader I get this window message:

“ardour: weird plugin dialog”
"You attempted to add a plugin (BLAHBLAHVST)
The plugin has two inputs
but at the insertion point there are
only 1 active signal streams

This makes no sense - unless the plugin supports
side-chain inputs. A future version of Ardour will
support this type of configuration".

I can only verify this on one machine, my main studio desktop is still running 2.4.1 for the time being.

Well at least I was correct in assuming it was on the fix list, any insight or further instruction very much appreciated, this is the ONLY thing I have any issues with Ardour even with the VST Horror stories, the list of improvements over the last 3 versions are nothing short of incredible!

this is probably a VST specific issue. you could confirm this by trying any 2-in LADSPA plugin in the same scenario. i have not built VST support for a couple of years, and so i tend to miss VST-specific issues.

thanks for your enthusiam about ardour.


I did as you instructed and selected “TAP Reverberator”, “SC4 Stereo”, and the “Stereo Amplifier” all gave me the same “weird plugin dialog”. Weird Indeed!?

I guess I better get hip to IRC and see what I’m doing wrong, since others no longer are reporting this issue. Thanks for the time being.

I get the same message, I thought that you HAD to only add stereo effects to stereo channels

i was suffering from dementia.

this behaviour is the way ardour has always been. we will “duplicate” a mono plugin if you use it on a stereo track, but the implications and complications of using a stereo (2in) plugin on a mono track are something that we do not tackle at this time.

sorry for the misleading information. the plan is to eventually automatically add a 1->2 splitter plugin. you can do this manually yourself, right now (its in the swh plugin collection).

Ah ok, thx for that…now I understand


@Paul, thanks for the bad news, at least now I know the rules of the game. I have been using the Harris splitter and it works well, it’s just awkward panning a mono track after it’s been split into a stereo track Oh well!

Generally speaking Ardour is unique in this way, most other DAW’s handle this kind of thing behind the scenes and automatically manage the I/O pins on the plugins, Ardour is actually being more honest about it!

GMaq, the problem with “the track being split to stereo” is caused by the plugin, unless its an odd case of a 2in/1out plugin. Most plugins that take 2 inputs have 2 outputs so after the plugin is added, you’ve got two signals to pan around independently of each other. This is partly why so many proprietary plugin sets (e.g. Waves, various TDM bundles) come with 1in and 2in versions of most of the plugins. It looks really wierd when you see the listing of plugins, and I’ve always found it rather offputting, but this is one of the main reasons why its done.

Note that we do automatically handle the case of adding mono plugins to >1 in tracks (or more generally, adding an Nin plugin to an Min track, were N is an integral factor of M). We just don’t handle the “opposite” case automatically at this time.


Thanks for clarifying, I understand now…so Ardour is only displaying the streams as handled by the plugins themselves regardless of “manufacturer”. Verdict - Not an Ardour issue, Gotcha!

Not to cuss in the Ardour forum but I did notice while playing around with REAPER some time ago (hides behind desk) that it has a little utility within their plugin interface to connect and change the VST pins manually if the user so desires, I realize that the SWH Mono to Stereo Splitter is doing one part of this, what about the addition of a utility or dialog to manually connect the pins?