Sidechain limitations with submix and nested tracks

[chagzuki]

I'm trying to clean up some drum and bass interaction with sidechains.

My first move was to route several percussive tracks to a single track which would provide the sidechain input. This edit is cpu heavy and I noticed that cpu load was increased by around 8% with this routing, so I opted for a submix track instead, which didn't significantly increase cpu load. It seemed odd to me that those two options would produce such differences in cpu load... anyhow, on proceeding to set up the sidechain input I realised that submixes can't be used as sidechain inputs. Bugger, so back to the track-nesting option. In this case the track can be selected in the menu, but nothing happens: the signal isn't received by the plugin, despite the fact that the audio is clearly being processed within that track. ? Confusion. A track is a track, right?

Is this a bug or part of the architecture, or something gone weird with my specific edit?

[spoontechnique]

The architecture of submixes is odd. I don't fully understand it, and it is counter-intuitive. For example, you can't flatten clips or render individual tracks within a submix. I think I've asked about changing it in the past, but I get the sense that it would require some serious reworking under the hood.

It's not a you problem, submixes just have certain traits and limitations.

[chagzuki]

The architecture of submixes is odd. I don't fully understand it, and it is counter-intuitive. For example, you can't flatten clips or render individual tracks within a submix. I think I've asked about changing it in the past, but I get the sense that it would require some serious reworking under the hood.

It's not a you problem, submixes just have certain traits and limitations.

That still leaves the question as to why a normal track that has other tracks routed into it doesn't work as a sidechain input... as I type this I'm guessing that any audio originating from that track would work as the sidechain input but that audio going through it from other tracks still wouldn't. I don't know what the hell's happening there.