A question regarding the physics of M-S stereo micing

M

mcolling

New member
So, I understand M-S stereo micing and how to accoplish it with the side, figure-8 mic added to the middle, directional mic in phase in one channel and out of phase in the other. My question is: How does this produce an accurate stereo image? Wouldn't this produce a stereo image that is not actually representative of the environment?

If I am wrong, could somebody run me through the mechanics whereby this technique produces an accurate stereo image?

Thanks

PS. This may have something to do with the way a figure-8 mic works that I do not understand.
 
bennychico11 said:
http://www.uneeda-audio.com/ms-mat.htm
there too

things get confusing once you start including the MS Matrix circuit, which seems like only some people actually talk about when refering to this technique...don't know why. poormans way i guess, lol
Click to expand...



Because M-S matrixes are completely unnecessary. They do NOTHING which you can not do simply by using three channels on a console. Additionally, most matrixes are very limited in what they can do as far as the width of the signal. Knowing how to do it yourself, and using simple technique is far more flexible.


Light

"Cowards can never be moral."
M.K. Gandhi
 
i would think the stereo width of a console would be more limiting than a Matrix would be. with something like this: http://www.uneeda-audio.com/mat03.pdf you'd get even more stereo width control PLUS still have more width control when it gets back to the console?
granted I've never even tried one of these units let alone seen one...just throwing out ideas. :cool:
 
bennychico11 said:
i would think the stereo width of a console would be more limiting than a Matrix would be. with something like this: http://www.uneeda-audio.com/mat03.pdf you'd get even more stereo width control PLUS still have more width control when it gets back to the console?
granted I've never even tried one of these units let alone seen one...just throwing out ideas. :cool:
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There is no way to get wider than the 2 out of phase side mic channels and there is no way to get more mono than the mid mic. The control comes from you balancing the two in order to get the desired effect.
 
/\
¦¦

What he said.

Hey, has the Microphone University disappeared or is it just me? I went to the DPA site and the links to it are there but the pages have gone!
 
sorry for going here, because i'm sure this is somewhere in the big thread but,

how the heck is ms mono compatable??????????????
 
oh crap, i finally get it.


your COUNTING on complete cancellation.

or am i still wrong????
 
Farview said:
There is no way to get wider than the 2 out of phase side mic channels and there is no way to get more mono than the mid mic. The control comes from you balancing the two in order to get the desired effect.
Click to expand...

i don't know. after reading that website i linked to, it appears using something like the Deluxe MS-decoder could give a more wider S signal. it looks like the circuit will have two pots giving it a "stereo-ness" that can go from mono-sounding to extreme wide. then after that, i'm guessing it come back through the insert returns...and then you'd have the pan pots on the two channels. i'm guessing this might be the way stereo-enhancers work giving a mono signal a superwide stereo sound?

i'm just speculating after reading this and all...like I said, I have never used one of the matrices either, i've always done it the other way.
:)
 
bennychico11 said:
i don't know. after reading that website i linked to, it appears using something like the Deluxe MS-decoder could give a more wider S signal. it looks like the circuit will have two pots giving it a "stereo-ness" that can go from mono-sounding to extreme wide. then after that, i'm guessing it come back through the insert returns...and then you'd have the pan pots on the two channels. i'm guessing this might be the way stereo-enhancers work giving a mono signal a superwide stereo sound?

i'm just speculating after reading this and all...like I said, I have never used one of the matrices either, i've always done it the other way.
:)
Click to expand...
I do know. you cannot get wider than 2 signals in separate speakers. The out-of-phase-ness makes it seem like it is coming from outside of the speakers. That's it! None more stereo. You cannot get any more mono than having the same exact signal coming from both speakers. None more mono. Period.

In order for the ms decoder to work properly, you would have to have the console channels hard panned.
 
Farview said:
I do know. you cannot get wider than 2 signals in separate speakers. The out-of-phase-ness makes it seem like it is coming from outside of the speakers. That's it! None more stereo. You cannot get any more mono than having the same exact signal coming from both speakers. None more mono. Period.

In order for the ms decoder to work properly, you would have to have the console channels hard panned.
Click to expand...

well, your last sentence clarified it the most.
i guess, yeah...technically you can't get more stereo than stereo. so are is everyone here saying that you will get the SAME sound doing the simple "flip the polarity on a multed signal" as you would using a Matrix decoder?? a Matrix decoded signal returned to the console will sound just as wide as panning the multed/flipped S signal?
 
bennychico11 said:
a Matrix decoded signal returned to the console will sound just as wide as panning the multed/flipped S signal?
Click to expand...

Only if it's properly mixed with the M signal panned center. The stereo comes from the sum and difference created between the M and the 2 (+ and -) S signals. And yes, using 3 channels on the board will do this just as well as any matrix box.

Scott
 
hmmm, i think i'm starting to see it. i guess i was thinking that with a matrix, you'd still mult the S signal before sending it for processing...but i'm seeing now this is not the case.
i'd still like to hear the difference one day.

thanks
sorry to drag this thread on.
:cool:
 
bennychico11 said:
hmmm, i think i'm starting to see it. i guess i was thinking that with a matrix, you'd still mult the S signal before sending it for processing...but i'm seeing now this is not the case.
i'd still like to hear the difference one day.

thanks
sorry to drag this thread on.
:cool:
Click to expand...


There IS no difference. The only reason people use matrixes is because setting the levels of the two sides signals can be a bit annoying. Actually, it is not at all difficult. The difficulty comes in CHANGEING the level of the MS signal when you mix, if you decode at mix down (and I for one don't really see the point in decoding to tape) the level of the two side signals MUST remain EXACTLY the same, or it doesn't work. That is easy with automation, but difficult without it.

Actually, come to think of it, the main reason people use matrixes is probably because some companies marketing company told them they needed it. They don't actually do anything useful, but if you don't know the theory behind it, advertising mooks can sell you anything.


Light

"Cowards can never be moral."
M.K. Gandhi
 
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