In some of my regular events produced with vMix, I always have two particular use-cases which need a flexible audio side-chain compression:

1. MICROPHONE DUCKING: Allow input devices (microphones, attached to the Master bus plus a "marker" bus) to be temporarily "ducked" (volume reduced) as long as output devices (callers and media, monitored on another bus) are active. This prevents nasty echos or even full loops on our stage.
   
   
2. TRANSLATER OVER-SPEAKING: Allow one or more remote translators (sitting on vMix Call inputs and mixed on the Master audio bus and additionally monitored on another bus) to "over-speak" the program (usually received via NDI from the main vMix instance and mixed on the Master audio bus after being "dimmed" on their bus).

Unfortunately, vMix does not support any type of side-chaining in its VST plugin chain. The only somewhat similar solution is WT Automixer (which I use in addition to balance the microphones). So, instead of having to route all audio to an external DAW and back into vMix again for the above use-cases, I decided to write a new vMix script which somewhat emulates an audio sidechain compression and just through its configuration parameters can support both of the above use-cases with the same implementation.

As I'm sure others also might have one of the above (or similar) use-cases, find my vMix script as Open Source under: audio-sidechain.vb. Happy side-chaining!