(A hybridization of other methods)
I've heard alot of questions about side-chaining in cubase lately. There are alot of ways to do it. Here is one I've adapted from some reading. It's a bit illusive to get set up, as cubase doesn't technically support side-chaining. Once you've run through the process once, tho, it's not difficult, and you'll be using it all the time no doubt.
You will need SX specifically for this method, as it uses Quadro channels.
First you will need Voxengo Crunchessor installed. Alternatively a free compressor which will work with this method is the SideChComp. It is what I will be using in this example. I’ve hosted it at http://www.epicacademy.com for you guys.
http://www.epicacademy.com/downloads/de ... ChComp.rar
First off, press F4 to bring up the VST Connections window. Alternatively, you can click on Devices->VST Connections.
In the VST Connections window, click on the Group/FX tab and then click on the Add Group button. Then select Quadro, and hit Okay.

Right-click on the group that you just added, and select Add Child Bus->Stereo.
Now right-click on the group again, this time selecting Add Child Bus->Sereo(Ls Rs)

Your VST Connections window should now contain your Quadro group and the two Child Busses as shown.

Close the VST Connections window.
Now, for traditional ducking, we will route a send from our kick to the group’s “Stereo (Ls Rs)” Child Buss. To do this we have just selected the Kick channel (1), then brought up its Channel Strip (2). Next we click on an available Send track (3), and route it to “Stereo (Ls Rs)” child bus (4). We then click on the Pre-Fader toggle (5), so that we can adjust the amount of signal sent without the volume fader affecting the side-chain once it is set up. It just makes mixing easier later.

Turn on the Send channel with the On button, and add some volume on the send by dragging horizontal bar to the right so that it looks like the picture below.

Now we are going to take our bass track, and route the channel output to the “Stereo” side bus. To do this we brought up the Mixer by pressing F3. Then we located our bass track and clicked on the Channel Settings button (1). Next we selected the channel output and routed it to the “Stereo” child bus (2).

Finally, we need to insert our compressor as an insert effect in our group channel. To do this, as above, we have pressed F3 to bring up the mixer (if it was not still up) and then located our group channel. Then we clicked the Channel Settings button, as we did in the previous step. In the Channel Settings window of our Group, we click the first Insert slot (1) and then select the compressor we want to use – either Voxengo Crunchessor, or the free SideChCompSt (2).

Adjust the amount of signal being sent from the Kick track, and play with the parameters on the compressor to adjust the effect. To hear the effect at its maximum, turn the threshold all the way down and the release to the shortest possible value, similar to shown.

Adjust the ratio. Now from here you can just continue to play with settings to fine tune the effect, so that it seems like the bass is playing basically seamlessly, but without the mudiness that may have existed before.
There are many other possibilities for side-chaining. Try applying it to delay signals, using the original signal as the signal being used as the side chain. This will allow you to have heavy delay, but the delay will only really be heard when the source material is not playing.
Try using it exactly as we have set it up, but apply it to pads instead of bass. Then we have that huge boomy effect heard in a lot of house.
There is no one single use for side-chaining. Experiment and play and you will likely come up with some creative new uses for the effect.
I really hope that this tutorial will help someone out, and get you started using side-chaining! There are a few other ways to do this. You can use the left channel to control the right channel for mono side-chaining in many methods, which would work in SL. You can feel free to PM me with questions - I'm busy but I'll try to make time. Please don't ask about using side chaining in other environments tho.
APPENDED
Justin Todd on DOA told me that the Solalksis SC compressors also work.
Also he mentioned that the OtiumFX Beatpuncher works.
The URS console compressors do not support sidechaining in cubase - only TDM (as far as I can tell)
Also another very simple method I've discovered is by using a free plugin called Sidekick v3, located here:
http://www.twistedlemon.nl/site/index.p ... &Itemid=32
Basically, you drop a copy of it in a bass insert channel, and a copy in a kick insert channel. Sidekick will automatically assign a different "virtual" channel to each instance.
Now in the instance of Sidekick running your bass instrument insert, under "use virtual channel", select the channel that your kick is on. Change the parameters to get the desired effect. Ensure that "bypass" is off on the bass channel. Make sure that Ducking is selected (Keying is sidechain gating/expanding, rather than compressing/limiting)
