ahhhhh! haa!! found this on another forum. very usefull indeed.
If anyone interested how to do it
Detailed description of "True Stereo Side-Chaining" with
Voxengo Crunchessor in Cubase SX3:
(testet with Crunchessor1.6 und Cubase SX3.1.0.933)
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The following example will use a kick drum track to duck/compress a bass line track:
1) Define a new Quadro Group and in this group 2 child/sub-groups ("Stereo" and "Stereo (Rs Ls)").
(How to do: See Page19 in Operation Manual of SX3)
2) Route Bass track directly to "Stereo" of the Quadro group.
3) Route Kick track directly (or with Pre-Fader Send (see below)) to "Stereo (Rs Ls)" of the Quadro group.
4) Insert crunchessor in an insert-slot of the Quadro group.
Start with the preset "Club is pumping" (or pull the Drive-knob to maximum)
in Crunchessor to see/hear the effect.
Choose a Side-Chain channel in crunchessor (in this case "SC: 3+4").
Leave the Crunchessor window open to see the effect via the gain reduction meter:
When the kick drum sets in, the bass track will be ducked/compressed according to the
compressor settings applied to the plug-in.
Routing with Pre-Fader Send:
Why this method ?
Of course you can route the kick track directly to the Quadro group,
but you won't hear the kick drum at the stereo output bus in this case.
a) Route a send-slot of the kick track to the Quadro group and activate this send-slot.
b) Set Pre-Fader switch to ON (the "at" symbol).
(This is necessary to retain the control over the volume slider for the kick track)
c) Set the Send-Amount slider to 0 (CTRL left click on the slider).
If you dont' have Crunchessor, there's a nice freebie for stereo side-chaining here:
http://www.geocities.jp/webmaster_of_sss/vst/index.html
Happy Side-Chaining !