ummm.

that's a strange question, just due to the fact that those are miccing techniques, and once you'll have m/s setup with a fig 8 and a cardiod mic, I mean assuming you have selectible polar patterns you can switch over to x/y or blumlein with reasonable ease, or just use a regular spaced pair. I'm getting the impression that you've already tracked though, and are in the mixing stage, in which case, you should probably just stick with what you have, because it's probably going to be pretty phasy otherwise.

so basicly, it's a mic choice thing.

yes
some mastering desks use sum and difference to play with stereo width and special compression techniques
L-R and R-L stuff
part of which used in TV, stereo/mono transmission stuff

Mid = Left + Right
Side = Left - Right

Easiest way to get the mid channel is a mono mix of both channels with -6dB gain. To get the side channel invert the polarity of the right channel, mix the result with the left, and drop the gain by 6dB to match the mid.

Thanks IIRs, that's just what I wanted to know.

Zacharym, I understand my question might have sounded strange without any details... sorry.

I asked this because I'd like to tweak M and S channels of my mixes separately. I have been demoing MD3 for powercore and I found the MS mode very usefull. So I was just wondering if I could do the same with what I own.

MS processing Rocks 8) and its usually easy to set up once you understand the principle.. I like to do it inside Tracktion racks :D

is it common to eq and compress this way?

I'm not sure about "common".. but if I'm manipulating a stereo signal I usually find it more useful to deal with M/S than L/R.

I use it all the time during mastering if I want to do something to vox only. It's also good for spreading stereo imaging or solidifying the center image.

J.

muwahaha....thanks guys

M/S to L/R is the same process as L/R to M/S

i use waves M/S matrix