I just started screwing around with the LSP suite of plugins and I’m trying to use it’s stereo compressor on a voice acting project I’m doing for fun. I redubbed the lines of a character and want to sidechain my voice into a compressor that sits on the audio track of the original video, so that it’s audio is attenuated when my voice comes in.
The LSP plugins are quite dense and there are a lot of them that do similar things, it seems. I’m at a loss to how sidechaining works here. Compressor Stereo has sidechain options, but I can’t get them to respond to any input from another track. There is another plugin called Sidechain Compressor Stereo which looks identical, aside from having “external” as an option in IT’S sidechain menu, where the standard compressor didn’t. I can’t get it to work either.
First off, why would I want to sidechain from anything other then an external source? Isn’t that the whole point of sidechaining things, or am I mistaken? Secondly, if the sidechaining variations of these compressors are hardly changed from the originals, why split them in the first place?
I feel like I’m missing something obvious here. Please let me know if I am.
EDIT: I got it working and it’s doing it’s job really well. I’m still don’t get why these are separate plugins, though, and what many of the options in the sidechain setup menu really mean, including the “reactivity” control. The guide describes it as “reactivity of the sidechain signal” which I don’t find helpful either. Again, am I missing something here?
I think LSP 1.2.22 is buggy when it comes to sidechaining.
At least the LV2 version.
It works as expected in 1.2.21:
Use the LSP Sidechain Compressor
Set Sidechain->Setup to External
Click the Pin Management icon above the Menu entry, click Sidechain and select the kick drum (in my case)
Set an appropriate Threshold in the Compressor area.
1.2.22 has reworked the GUI layout so that the Sidechain options are behind its own button submenu, and no matter how I try I can’t get it to work properly.
Also, if I set it to Peak instead of RMS and click Listen I hear terribly distorted audio from the main track, whereas I hear the expected kick, and nothing else, if I do the same in 1.2.21
I’m having a very similar experience to yours. It’s working now, but I think I had to put the sidechain in, like, feed-forward move? Because external wasn’t doing anything even though you’d think it would.
Yeah, “Feed-back” gave me the expected “External” result.
I’m guessing that the GUI reworking in 1.2.22 led to the wrong ordering of the options; so when we select “External” we’re actually getting one of the Feed options (or the Link one) and so on.
Edit: lsp-plugins-compressor/src/main/meta/compressor.cpp changes the ordering in const port_item_t comp_sc2_type from F-f, F-b, Ext, Lnk in the previous release to Ext, F-f, F-b, Lnk and some backend apparently wasn’t updated to reflecting that.
So selecting the third option (F-b) in the drop down menu gives you the Ext functionality.
Yes, it is a regression, and I also met it when working on this feature: Feature request: Dry/Wet mix for all the Sidechain plugins · Issue #494 · lsp-plugins/lsp-plugins · GitHub
In short, there was an incorrect change by the UX designer: Boris wanted to make ‘External’ option default for plugins with separate sidechain input and moved the ‘External’ item before the position of ‘Internal’ item instead of changing the default value for the corresponding parameter of the corresponding plugin.
That’s my fault, too, because I didn’t validate his code changes.
I already fixed the regression in the ‘devel’ branch of plugins but the final fix will come in the 1.2.23 release.