If it were me I would truly split your stereo track into two individual tracks. Once you have a mono track representing the stereo left and a mono track representing the stereo right things get pretty easy. I use Audition 3 so I can't comment really on how to accomplish the task in Sonar.

Copy the now mono side track to a third track and invert the phase. Pan your side tracks hard left and hard right respectively. Send them to a bus or link them some way and insert your fx on that bus.

Your now mono center track will be panned center like it should be and you can do what you will to it.

When you get get things manipulated where you want them bounce the three tracks back into a stereo file in whatever format you choose.

YMMV

Copy the now mono side track to a third track and invert the phase. Pan your side tracks hard left and hard right respectively. Send them to a bus or link them some way and insert your fx on that bus.

hmmm, mono side track.
But all you have done thus far is created a mono Left track, and a mono Right track.
Where did the mono "side" track come from?

1.)Create 2 Stereo Tracks
Track 1 and Track 2
2.)Pan Track 1 hard left.
3.)Pan Track 2 hard right.
4.)Insert on Track 1: Voxengo MSED plugin. Set to "Encode".
5.)Insert on Track 2: Voxengo MSED plugin. Set to "Encode".

6.)Copy the Song/Mix to both of those Stereo Tracks.
Note: Ensure they are both alligned.
I know in Sonar 7 you just hold Ctrl./Shift, then click and drag a copy
of Track 1 to Track 2.
Ctrl. is the Copy function, but also holding Shift keeps the sound clip
locked in time while copying to another track.

7.)Insert on Master Bus: Voxengo MSED plugin. Set to "Decode".
This instance of the Voxengo MSED that is set to Decode, is decoding the M/S.
Basically giving you back your stereo track.

Play audio. You should basically hear your song/mix as usual.
Now disable/bypass the Voxengo MSED plugin that is on the Master Bus
You will hear the "Mid" programme material on the left.
You will hear the "Side" programme material on the right.
This is because you have bypassed the Master Buses ability to "Decode" the
M/S Matrix, by bypassing the Voxengo MSED inserted on the Master Bus.

Want to do some Compression or Eq to the "Mid"?
Insert a Compressor or Eq onto Track 1. Adjust to taste.

Want to do some Compression or Eq to the "Side"?
Insert a Compressor or Eq onto Track 2. Adjust to taste.

Im sure that is the way. Please correct me if Im wrong.

I may have misunderstood your original setup. When I record two mic's MS into my portable 2 track flash recorder, the left side of the "stereo" track is the and the right side of the "stereo" track is the . Unless you have a MS decoder inherent to your 2 track recorder this is probably similar to your setup. If this isn't how your set up works then disregard the rest of this post.

If I drag and drop this audio file off of the flash drive onto my audio computer it shows as a stereo file. I merely split it back into its left and right components creating two individual wave files where there was one stereo wave file. The alternative is to record it real time via SPDIF from the flash recorder into my DAW as individual MS components.

Remembering that I use Audition 3, this is the next step. Now I have the mid and side components to work with in a multitrack session. I add into track 1 and label it as such. I add the into track 2 and again into track 3. Track 2 gets panned -100 and track 3 gets panned 100. I also invert the phase of track 3.

Now I create a bus and route tracks 2 and 3 to the bus. It is in this bus that I would insert FX or EQ or adjust the side level within the master output.

When I get what I want from the sound I bounce the session into it's own stereo wave file and split into individual movements.

If I'm not clear I can try again.

NickSoldier wrote:

Copy the now mono side track to a third track and invert the phase. Pan your side tracks hard left and hard right respectively. Send them to a bus or link them some way and insert your fx on that bus.

hmmm, mono side track.
But all you have done thus far is created a mono Left track, and a mono Right track.
Where did the mono "side" track come from?

actually he is right by doing an inversion of phase and combining the right mono track with its inverted image you cancel the mono part of your initial track because in your initial split stereo signal only the side signal is different the center part is going to be the same thus if you take one of the mono signals and then combine it with its inverted image you are doing what is called a phase cancellation of the common signal in this case the mono part of your signal thus you get left with your side signal.... after applying FX send that side signal to 2 different AUX one panned hard left and the other one hard right combine them with a third AUX on which you send the mid signal or mono part of your original track panned dead center on which you can apply seperately your desired effects... but don't forget to cut down your signal level by 6dB to avoid clipping because merging the signals increases the overall level of your final mixdown...i forgot to mention your signal should be perfectly aligned if not you won't get the desired result....after all that is done route those 3 AUX to a stereo bus on which you can apply more global FX if needed... welcome to Mid/Side signal recording....yes sometimes you want to maybe apply a different level of compression to the mid and the side part of signal independantly...