How does a vocal rider work? Can I build one with Renoise native fx?

One of my favorite dynamics processing fx is a vocal rider. But how do they work, technically? Would it be possible to create a vocal riding effect using Renoise native effects?

Yeah, you can.
Send every track into one send, send the vocal to the next one. Then signal follower of that mixing bus (every track besides vocal) will influence gainer of the vocal send. Also place a gate on the vocal send, because you dont wanna to have that noise leveled.
It is very primitive vocal rider but it should work…

I don’t think that’s how the existing leveller plugins work. They simply insert into an FX chain, with no sidechain. I am guessing they are just a specially designed compressor.

I have experience just with Waves Vocal Rider but i think it is how Vocal Rider should work and look. It is not a compressor…

You can use vocal rider by two ways:
Sidechain it - then vocal is influenced by power of other parts in the song. If you have a part where a lot things is going on, vocal will get louder and you can hear it better (theoretically).

If you dont sidechain it you just define threshold of vocal volume. If it goes down, plugin will boost it up. If it goes up, plugin will lower it. So if you have a part where you whisper this plugin will get your voice louder. With sidechain it can recognize that music is also quiet so your whispering wont be boosted.

It is not compressor because it supply something what is better done by a hand. It moves by gain fader (it should be done before you apply any effects) so it preserves dynamic.