iPlug2 Forum

IPlug2 Sidechain

Tell me how to enable (docs) the button in DAWs for sidechain, I’m sure there is a code for this in docs. Thanks!!

I seem to remember it has to do with how you set the I/O channels in config.h

For example try this:

#define PLUG_CHANNEL_IO "1.1-1"

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is there any way to explain this?

This includes the sidechain button in VST2/3 but what to do with AU?

There is an example that shows you how in the examples folder

it says here that different configurations are separated by a space; input and output are separated by a minus sign; and different busses are separated by a dot.

I compiled the example, and I didn’t see that sidechain icon in CUbase, for example. However, I have implemented the sidechain process and added a sidechain. But AudioUnit DOESN’T show me the option to specify the input for the sidechain.


Therefore, I would like to understand why this works in VST2/3 but not in AU, and how to fix it.

The IPlugSideChain example shows the SideChain input in AUv2 in Logic, and VST3 in Cubase 11 here.

PLUG_CHANNEL_IO defines all the valid combinations of input busses

#define PLUG_CHANNEL_IO "\
1-1 \. <- one mono input bus, one mono output bus (no sidechain)
1.1-1 \ <- two mono input buses, mono output (mono sidechain)
1.2-1 \  <- two input buses, mono output (stereo sidechain)
1.2-2 \ <- two input buses, stereo output (stereo sidechain)
2.1-1 \ <- two input buses, mono output (stereo sidechain)
2.1-2 \ <- two input buses, mono output (stereo sidechain)
2-2 \ <- one stereo input bus, one stereo output bus (no sidechain)
2.2-2" <- two stereo input buses, one stereo output bus (stereo sidechain)

Maybe LogicX does not know yet that the sidechain exists?
“For anyone reading this thread, the story is: If you change your AU’s channel IO options, you need to also bump the version number for LogicX to detect the new options correctly.”


I feel like a jerk when it works that way. Thank you!