VST 3 multi-bus support

Starting with tomorrow’s nightly build, Ardour 7.2-123 supports VST3 plugins with multiple I/O busses. This allows for instrument plugins to have dedicated additional outputs.
Notably drum software which have direct outs (e.g. ezdummer, AD2), and also VST3 synths (e.g. surge) can now be used to their full potential.

Since the plugin meta-data is cached, this change requires VST3 plugins to be re-scanned, which can be initiated in Ardour Menu > Window > Plugin Manager.

This is a significant change, and while it holds up well in preliminary testing, there might be plugins that have issues. Please test, and if you encounter issues with a specific VST3 plugin it would be great if you could file a bug report at tracker.ardour.org. So that by the time we release Ardour 7.3 most kinks are worked out.


This is FANTASTIC news! Ardour just keeps getting better & better. THANK YOU to the devs for making this happen so quickly!

Thank you for this update: previously my multichannel VST3 plugins were recognized as “mono” but now all the inputs/outputs are available and fully functionnal.
Well done!

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Nice one! Just what I was waiting for (EZDrummer3)… Will this feature be available with the next stable upgrade? :slight_smile: regards

Thanks for the addition of this feature! It detects the number of channels properly now (tested with Kontakt 6 VST3). However, I’ve noticed a couple of significant bugs with parameter changes since the addition. The bug report is posted here.

Love Ardour and a big thanks to everyone and all the hard work on an amazing product.

Has anyone tested Sonobus multi-channel outputs? I,m having problems with Sonobus with AV Linux?

Tried to get the individual channel out of Sonobus into assigned tracks in Ardour to record session.

If i have of a plugin a vst2 and vst3 variant - what do you recommend to use? What is more resource efficient?

I believe VST3 is technically more efficient as the plugin gets automatically disabled when not in active use (or something along those lines).

The plugs I use are mega cpu efficient (mainly Airwindows and ACMT and GVST) or need multi-out (Renoise Redux and Ugritone Drums) so I just stick with VST2 versions myself.

There may be more to it than that however, hopefully somebody else will chime in.

4 posts were split to a new topic: Airwindows VST Performance

For the DSP load, you can check yourself. In Ardour open Window > Plugin DSP load and compare the worst-case performance.

Ardour does not do that. Plugins are always active. Plugins having variable DSP load is dangerous. Ideally the load is constant regardless of the input.

Say you play a synth live on stage, and its DSP load increases beyond what your system is capable of, just because you play too many notes at some point.

Or when mixing/producing: you load a few plugins and all is fine, until you press play/rec, plugins all jump into action and overload the system…

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This is great! This missing feature has been the main reason stopping me from giving Ardour a decent try. I’ve subscribed and tested the nightly, and initial tests are working well with VCV Rack on linux.

The ability to easily send out mono channels with minimum hassle is great also. Often the multi-bus implementation is hard-wired to only make stereo pairs available.