Lets talk Mid/Side technique

[tubedude]

Get into all the basics and more advanced ideas of it.
I know what it is and how to basically make it work but WHY does it work? What does the processing do? What are some cool tricks? Where do you like to use it? Where do you hate it? Why isnt it more popular? What works particularly well as far as mic arrangments?
In the previous issue of Tape Op a reviewer mentioned processing the side different than the mid, etc... seemed weird to me. I think this technique is a little weird to a lot of us. Waves Stereo Imager has M/S capabilities. I havent tried it yet but intend to now that I have a figure 8 or two lying around.
Anything I should try in particular?
Spill forth thy knowledge.

[max cooper]

there's a good article that explains it mathematically, which I think is the best way to think of it:

Mathematically it works like this...

M = L + R

S = L - R

Therefore...

M + S = (L + R) + (L - R)
M + S = 2L

M - S = (L + R) - (L - R)
M - S = L + R - L + R
M - S = 2R

http://www.record-producer.com/learn.cfm?a=2472

Originally Posted by tubedude

In the previous issue of Tape Op a reviewer mentioned processing the side different than the mid, etc... seemed weird to me.

Yeah, I don't know why that's weird. Anything that's a discrete channel can be processed differently.

People react that way when I say I sometimes use a D.I. for the "Mid" channel, but if it works, right?

[feyshay]

What is it and how do you make it work?
Is there where you use a figure 8. Duplicate it. Pan the original left and the duplicate right. Then reverse the phase of the duplicate?
Or is that something else?

[thenewyear]

Yep MS was originally a stereo mic technique that guaranteed mono compatibilty. You are guaranteed to have no phase problems when summing MS signals to mono although the resultant mono can sound radically different to the stereo signal and can produce a sound totally lacking in depth.

An MS mic arrray consists of a figure eight mic pointing 90 degrees of axis to the source (this is the S or 'side' of the signal) & another mic pointing directly at the source (this is the M or 'middle' of the signal). Then on the console the S is multed and one channel has its phase flipped.

The stereo image produced by an MS array totally depends on the pick up pattern of the M mic, if it is a carioid it should produce similar results to an XY pair but you can use almost any pick up pattern for the M to get different results.

These days more and more mastering units take pre-recorded LR audio and let you manipulate it as MS (see Max's maths above) for stereo widening and a host of other tricks too.

[5down1up]

Originally Posted by thenewyear

These days more and more mastering units take pre-recorded LR audio and let you manipulate it as MS (see Max's maths above) for stereo widening and a host of other tricks too.

saw those units in some mixing racks as well. looks like squeezing the mid is a big part of todays sound. for mastering i do it sometimes. still, that dangerous MS box looks very interresting.

[starcrash13]

M/S is used a lot in film for recording stereo in the field like cars, trains, etc. because it can be set up to be very portable and you can control the width in post. That said, it's not the most "realistic" stereo image compared to, say, a pair of spaced omnis. For some great info, check out the DPA Microphones website and click on Microphone University. Also, Wikipedia "Stereophonic Sound".

This guy is pretty sweet (Neumann SKM140):