Sidechaining effects

I’m doing a Mid-side decoder, and want to be able to provide EQ on the side channel via a sidechain to the EQ plugin of the user’s choice. Who needs yet another EQ when you already have a gazillion perfectly adequate ones? I don’t think the VST spec has any explicit support for sidechains; don’t know about AU, and I’m sure different hosts have different ways of getting in the way, but I’m hoping that juce has somehow got this sorted out using some kind of IPC. Am I in luck?

If I get you right, then no. You’re not in luck.

There’s a couple of ways of acheiving what you want, but none of them elegant. One is to build in a host, and basically host the eq in you own plug. A pretty tricky thing.

A second is to make send and receive plugs to put before and after the eq in a chain in the host, which is sort of awkward to set up.

Don’t think so. There are compressor plugins with sidechain I/O; they offer some extra I/O channels and rely on the host to provide flexible routing.

For example, Live and Logic can do sidechain routing as you describe. But it’s not explicit – there’s no “sidechain mode”. Probably most other hosts with flexible routing work similarly.

AU does not have explicit support for sidechains, and actually I’m not sure what that would look like. Both the VST and AU systems can handle arbitrary connections of plugins; it’s up to the host to allow the user to set up complex networks.