mid-side confusion

[Cosmic Pig]

Is mid-side actual stereo or induced fakery?

Also, tell me if I got this right; one omni or cardioid facing the sound source, and one figure eight 90 degrees over top and upside down.

Omni panned center. Figure of eight copied to another track and inverted, then original and copy panned right and left.

Why would one use mid-side instead of ORTF? I hear mid-side is more mono compatible, but are there any other reasons? Mid-side seemed to sound more real to me but I wasn't getting the swing of left to right off the leslie rotor like I did with ORTF.

Thanks fellers.

Cos.

[Brendo]

Mid side is actual stereo.

This relies on the "front" of your fig 8 mic pointing to the left, and the inverted track panned right, to get L and R in the correct positions.

Mid is L + R
Side is L - R

So your left channel is:

L + R + L - R
= 2L

Your right channel is:

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

So you end up with 2L and 2R...

[Cosmic Pig]

Cool Brendo thanks. I gets it now.

So I gather it's popular mostly because of the control over the stereo field. I notice it's quite different from just panning an ORTF or xy.

Cos.

[malice]

Is mid-side actual stereo or induced fakery?

No, it doesn't. But it does induce phase problems if you try to widden the mid-side too much.


Also, tell me if I got this right; one omni or cardioid facing the sound source, and one figure eight 90 degrees over top and upside down.

better with a cardioid. the figure eight with the nul facing the source (the two lobes at exactly 90° from the cardioid).


Omni panned center. Figure of eight copied to another track and inverted, then original and copy panned right and left.

decoding as Brendo explained


Why would one use mid-side instead of ORTF? I hear mid-side is more mono compatible,

yes.


but are there any other reasons?

Yes: total control over the stereofield with less phase anomalies than if you narrowed a near-coincident couple (ORTF, NOS).

M/S falls in the coincident category, like XY and Bluemein.
It is somehow less wide than Near coincident or spaced, but it is precise for small ensemble (your source should stay in the 90° angle around the center, if a source is away from that angle, it will be very difficult to locate.


Mid-side seemed to sound more real to me but I wasn't getting the swing of left to right off the leslie rotor like I did with ORTF.
.

The best way to mike a Leslie of you want that swing is to mike at 180° side by side of the cab. But that has little to do with M/S anymore.

M/S is a great way to do overheads, for Jazz drums for instance. Or acoustic gtr, when you are not sure if you want stereo or mono.

malice

[otek]

I run digital synths through an amp sometimes, and mic the room with an M/S setup. This gives me a wide, very "organic" sounding room on sterile pads etc.

[Mixerpuppet]

M/S is a great way to do overheads, for Jazz drums for instance. Or acoustic gtr, when you are not sure if you want stereo or mono.

malice

I think that is a good description to keep in mind. To me I always thought in terms of having a mono mic with the ability to add or subtract 1/2 the room to taste. Sometimes mono is too direct and stereo isn't direct enough.


On a side note....

It all falls into fakery...

"Rarely" do we try to record and produce reality in music...

We try to create an experience...

[eagan]

Don't feel bad, Cos. I actually never really grokked it until not all that long ago in a thread in the old neighborhood where somebody was considering buying the Paia kit for their version of a M-S mic i a box. In the course of that, I looked at the whole thing and really thought it through for the first time, and finally actually got it. I knew how it was done, but it never had really sunk in before what was going on and why this actually worked.

At that point, I finally understood, first, that if mono compatability is a worry, that this was really the best way to go for stereo mic technique, and second, that the Paia kit being discussed maybe wasn't so great after all, because it wasn't "true" M-S micing, but more of a "pseudo-M-S" kludge.


JLE

[malice]

By the way,

as I was depicting mono compatibility over the 3 great family of stereo miking (coincident, near coincident and spaced pairs), I might have induce you in the idea that only coincident (XY, M-S, and Bluemein) were the only totaly mono compatible.

Actually, there is another very mono compatible system within the "spaced pair" category : the "Deca three".

but you need three mikes of course. And expensive ones to start with.

Am I sounding to geeky :D ?

malice

[Mixerpuppet]

Am I sounding to geeky :D ?
malice



French never sounds geeky... ever ;)




If Im able to I'll post my quad setup with some pics...

[Comte de St Germain]

Usually the side needs to be 10db down from the middle to work. That said, the image and low end afforded by M/S can be an awesome ticket.

[imagineaudio]

kinda OT, but lately I've been recording acoustic guitar and the occasional guitar cab with a room mic that I'll copy to a new track phase inverted, pan them hard L&R and delay them until I the desired effect. How does this compare to m/s? Obviously there is no "mid" mic, or is the close mic acting as the mid? Actually as I typed that, I realized it's not M/S because it's not really stereo....


I do like that, when summed to mono, the extra room tracks cancel out....


::go ahead about your business, nothing to see here::

[Brendo]

Actually, there is another very mono compatible system within the "spaced pair" category : the "Deca three".

but you need three mikes of course. And expensive ones to start with.

But anyone can do a pseudo-decca tree with 3 mics...

Two mics 2m apart. One mic in the center, but 1m forward too. Angle the side mics outwards a bit.

Voila!

Yeah... it's a bit dodgy... but it works well enough.

[malice]

But anyone can do a pseudo-decca tree with 3 mics...

Two mics 2m apart. One mic in the center, but 1m forward too. Angle the side mics outwards a bit.

Voila!

Yeah... it's a bit dodgy... but it works well enough.


Yes you can do this. But the thing with Deca three, is that it works best with a special type of omni mic that have a spherical capsule.

For your info, the best aclaimed microphone is the discontinued M50 from Neumann (12k a piece, minimum, more in the 15k range), the M150, or the Gefell UM900.

The thing is that these mike are not totaly omni directional, they starts geting more and more cardioid as the signal is getting higher in freq.

So basically, you can try to put three DPA 4006, it won't sound like a true decca three.

That said, Decca three makes real sense for large orchestra. Not something you have to do every weeks.

malice

[Brendo]

And when you do, you rent those mics. Easy.

But if you're just doing something small scale, the "Ghetto Tree" works just as well.

[Comte de St Germain]

I want another Bova Ball so I can use them for my Decca.


Is there an economical Decca Tree stand that one can purchase?

[malice]

Is there an economical Decca Tree stand that one can purchase?

I have seen one, but I don't remember where, i'll try to findout

malice

[Brendo]

surely you could weld one together in an afternoon?

[slabrock]

Why would one use mid-side instead of ORTF? I hear mid-side is more mono compatible, but are there any other reasons?

Brendo explained beautifully what Mid-Side really is.

Mono compatibility is one issue. Another, and maybe even more important is the fact, that a microphone capsule picks sounds differently from different directions. The bass response is best directly in front of the capsule.

Now, if we want to have the best bass in the center of our acoustic image, there's only the M/S and the Decca Tree which allow the capsule to point straight forward.

By the way, there was a Finnish inventor, Tapio Koykka, who patented a M/S based surround system (probably sometime in 1960's), which is still in use with many Finnish audio enthusiasts. The system is called Ortoperspekta and it really gives a nice stereo image allowing much wider listening area than ordinary stereo, 5.1 or 6.1.

Unfortunately his inventions went for the most part unnoticed, since the Ortoperspekta could easily have been a world standard instead of a curiosity.

Peace,

Slabrock

[Brendo]

Yeah, in mono, Mid Side becomes:

L + R + L - R + R - L
= L + R

[otek]

The thing is that these mike are not totaly omni directional, they starts geting more and more cardioid as the signal is getting higher in freq.

So basically, you can try to put three DPA 4006, it won't sound like a true decca three.


I wonder if the DPA Acoustic Equalizer spheres and/or the Diffuse Field Grids can help mitigating this?

None of them directly changes the pickup characteristics, but they do alter the frequency response on/off axis, and in the diffuse field, respectively.

[FredSanford]

I just used m-s today for the first time on a flamenco guitar. It sounded wonderful to my ears. I am thankful for the ms-decoder in Logic, because although I understand whats going on there (and even better after reading this thread) it sure is convenient to just put your cardioid on the left and your figure 8 on the right of a stereo track and insert the decoder and be done with it. What a coincidence that there is a discussion about here tonight!:Wink:

[slabrock]

I just used m-s today for the first time on a flamenco guitar. It sounded wonderful to my ears. I am thankful for the ms-decoder in Logic, because although I understand whats going on there (and even better after reading this thread) it sure is convenient to just put your cardioid on the left and your figure 8 on the right of a stereo track and insert the decoder and be done with it. What a coincidence that there is a discussion about here tonight!:Wink:

Even without a plug-in, it's not terribly difficult to drive the figure-8 in two separate channels and invert the phase in one of them :D

I have always thought that the decoder was for creating an M/S environment (not to be confused with the miking) fom an ordinary stereo. In M/S environment you can tweak the centerfield separately from left and right fields, which is very nice when you have a stereo ambience image and you want to compress the center tight and add some verb to the room reflection on outer edges.

Mastering engineers use M/S processing a lot.

Peace,

Slabrock

[FredSanford]

I guess it would be an advantage to be able to manipulate the mid and side channels separately. I will have to give it a try next time. Thanks for the insight Slabrock.:)

[Brendo]

on team down undah the overheads were m/s, and the m got more squish than the s.

[Comte de St Germain]

I wonder if the DPA Acoustic Equalizer spheres and/or the Diffuse Field Grids can help mitigating this?


Otek,

These mics have a sphere based on the DPA:

http://www.sageelectronics.com/images/bb1stand.jpg
I freaking love them.

[volthause]

Dammit, stop showing your balls! Everytime you show that pic I get ball envy!

:lol:

[eagan]

By the way, there was a Finnish inventor, Tapio Koykka, who patented a M/S based surround system (probably sometime in 1960's), which is still in use with many Finnish audio enthusiasts. The system is called Ortoperspekta and it really gives a nice stereo image allowing much wider listening area than ordinary stereo, 5.1 or 6.1.

Unfortunately his inventions went for the most part unnoticed, since the Ortoperspekta could easily have been a world standard instead of a curiosity.



My guess is that how it sounded faded into relative insignificance for people when they realized they would have to pronounce and spell it.

Well, maybe not.

But this is actually the first I've even heard of that one (although, on the other hand, I might be shown somewhere as "dumbest in class" in knowledge of mix technique around this joint).

Do tell more.


JLE

[maccool]

With the M-S technique, should the two mic's be as similar as possible?

I have only one Fig.8 mic, an LDC. For the M mic I have a choice of 3 different cardoids, 1xLDC and 2xSDC's.

I will try all three cardoids; since they are all very different from the Fig.8 mic, what are the pitfalls I should be listening for?

[slabrock]

But this is actually the first I've even heard of that one (although, on the other hand, I might be shown somewhere as "dumbest in class" in knowledge of mix technique around this joint).

Do tell more.

You asked for it :D

And no, i don't think most of the people have ever heard of Ortoperspekta. I posted some questions concerning "mixing in M/S for ortoperspekta" in the old PSW several years ago, when i acquired my own Ortoperspekta system.

I've even visited a movie theatre somewhere in Finnish countryside, where they used ortoperspekta surround system. I guess it was the home village of said inventor.

As far as i understand, the idea is that you have a mono L+R full spectrum speaker array in front, then you add two L-R satellites for the sides, invert a phase and cut away everything below 300Hz from the satellites.

Here's two ways to connect the speakers in Ortoperspekta. (http://www.kolumbus.fi/epap/voimaradio/ortoperspekta/ortoperspekta6.html)

Also a short lesson in Finnish there. There don't seem to be too much information about Ortoperspekta in English, but apparently Mr. Koykka is somewhere in league with household names like Alan Blümlein with his inventions.

http://www.pornaistenyrittajat.fi/java/pornaistenyrittajat/images/yritykset/10/Stereot.jpg

They still manufacture Ortoperspekta systems for home use under Mr. Koykka's brand name "Voima" (The Power).

Peace,

Slabrock

[dnafe]

In case anyone is interested Schoeps has a free M/S decoder plugin (for VST)

http://www.schoeps.de/dmsplugin.html