Strange Ace eq plugin as a-eq in latest ardour release

I’m running ardour on Linux and I see a strange new GUI for a-eq and the a compressor. It says ace eq, has a mixbus logo on it and looks updated with a new GUI. What is this. I can’t seem to find any info online about it

We’ve long wanted professional GUIs for the a-* plugins, but in the last three years nobody stepped up to provide commercial-quality cross-platform UIs.

Ben at Harrison eventually volunteered. a-eq is done, the others are functional but still being worked on. We’ve shipped them a bit early, so there’s no promo material yet.

There is the idea to re-name the a-* plugins with custom GUI to ACE-* (Ardour Community Effect), but the jury is still discussing the name-change.

PS. In case you prefer the old generic UI, that is still available (right-click edit-with generic controls), and the installer allows to opt-out of installing the Harrison.lv2 plugins, too.

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It’s a nice looking plugin. I hope ardour gets a dynamic eq as well

It’s unlikely that we’ll add and maintain a dynamic EQ, That is very specialized.

The idea for the a-* plugins was to provide bread and butter set of plugins for new users to get started, and create a good out-of-the-box experience for typical users.

The main issue with bundling plugins is that the release cycle is tried to Ardour releases. The benefit of plugins are that they can be maintained independently by 3rd parties.

For that reason we ship a set that’s robust DSP, and unlikely to need any updates:
an equalizer, compressor/expander, reverb and a delay.

It’s more likely that we’ll add a Limiter plugin (and perhaps a convolution-reverb), in the future. But that highly depends on someone volunteering to do the task. Overall we prefer to focus on Ardour itself, and allow users to pick plugins.

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I must ask since the Harrison logo now appeared in the GUI. Will ACE plugins stay free or do we need to license them from Harrison ?

They are, and will remain gratis (free of cost), but the source-code is proprietary. Ben used the existing Harrison toolkit because that was easy for him, but he is not at liberty to publish it under the GPL.

LV2 explicitly allows to have external separate GUIs. In the case of the a-*.lv2, the plugins did not have to be modified to make this possible.

@x42 Thanks for clearing this up.

Just a followup question. Is the ACE plugin “audio processing code” GPL and the GUI proprietary ? Or is every line of ACE code proprietary ? I’m just interested since I’ve been using those a-plugins a lot.

The DSP code has not changed and is licensed in terms of the GPL.

Only the custom GUI is closed-source (and the ACE GUIs also only included with binaries from

In theory anyone can create a custom GUI under any license for any LV2 plugin.
But someone needs to do the work, and making good UIs is a hard and time consuming task. – If someone creates a better GUI that is free software, we’ll happily ship that instead. I think Ben will be happy too. less work for him.

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Is it possible to get the new GUI to work in older versions of ardour possibly mixbus version 5

The EQ, yes.

You could copy /opt/Ardour-6.3.0/lib/LV2/Harrison.lv2/a-EQ_* to ~/.lv2/a-eq-ui.lv2/

However the delay plugin changed from v5 to v6 (support for dotted notes was added), so the plugin ports don’t match. Also the port-ranges for the compressor were relaxed.
For those to work you’d also have to get the new a-* plugins and replace them.

If @zamaudio is not up for adding one of his limiters in generic disguise (i.e. ZaMaximX2), perhaps I could put in a “plug” for a version of your x42-dpl or asking @SadKo for something from the LSP stable (with true peak option given the new loudness workflow).

+1 for an a- convolution reverb. I love the look of your convo.lv2 but I guess at low buffer sizes it is designed only for very short cabinet IRs? I can’t use it for adding halls and churches while playing live like I can with Klangfalter…

Also, I really love the new UIs for EQ and compressor :slight_smile:

Correct. That’s why there’s

Wow, excellent. The author does warn not to install it though :wink:

About the IR bundles you have listed, I have started converting some B-format ones to stereo from the openair library ( using a GNU Octave script if you want to list them at some point…

I copied the ardour 6.3 plugins into my mixbus and it works fine and I got the new GUI to show up. But I do fine at times the GUI locks up the system. Even on ardour 6.3 on Linux but at times I notice it’s fine and no issue.

Would that not imply or invite all manner of potential licensing ambiguity and / or conflicts? (And possibly make it difficult for the end-user to be sure of what it is they are using, and under what license or attribution? )

It’s the same as loading a proprietary VST plugin into a free-software DAW, or vice versa.

The LV2 DSP / GUI interface is literally just that: an interface. Any software can use the interface, regardless of the software’s license.

This is also possible for VST, the host can provide a custom view and controller and one can create custom UIs for 3rd party plugins too. VST3 makes this even easier since the Vst::IEditController interface is publicly exposed.

Yes I understand all that, and that’s not really (in fact, not at all) what I was referring to - your original comment appeared to suggest that someone could just take any existing LV2 and put a different GUI on it - technically possible, yes, but… the ambiguity, in that case, might be that you could have ‘a plugin’ (e.g. an ‘LV2’ ) potentially composed of a proprietary part and an open source part, and that it might not be clear to the user what the licensing of ‘the plugin’ is or even e.g. the attribution of an open source plug-in to which a proprietary UI may have been attached.

On a slightly different topic, when I tried the a* EQ GUI, the ‘Q’ control behaviour appeared incorrect. For example, dragging the Q control to the left, decreases the Q value, but, makes the filter appear sharper which is not what I would expect.
‘Q’ commonly denotes the ‘quality factor’ of the filter e.g. how good at filtering it is, therefore a high Q implies a more selective e.g. narrower passband not a wider one. Q is related to bandwidth, but not equivalent.

Last I checked Q was generally considered the inverse of bandwidth.