#1742913 - 04/28/07 02:04 PM
What my M/S article was SUPPOSED to say.
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J.J. Blair
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Due to editing, some details were left out or changed from my article on M/S mic'ing. One of these, regarding the matrixing, was extremely important. I'm sorry that the editorial staff overlooked this, as it will cause great confusion to anybody who tries this as it was printed. Here's how the article was supposed to read:
One of the biggest problem areas for less experienced engineers occurs when they start using more than one mic on a source. Whether it's multiple mic'ing in mono, or using a stereo pair, phase issues are a frequent culprit in not-so-great sounding recordings. When recording in stereo, the best way to avoid these issues is to use a coincident stereo pair. One of the most overlooked coincident stereo mic techniques is the M/S or "mid/side" configuration. It's a stereo technique that I personally use all the time, probably more so than X/Y or Blumlein.
If you are unfamiliar with M/S, here's the basic premise: You have two mics. One of them is figure eight, and the second is typically cardioid (as depicted in figure 1), but can actually be any pattern. The figure eight is your side mic, and points 90 degrees away from the source. The mid mic should point directly on axis to the source, at a right angle to the figure eight mic. The figure eight signal is then mult'd to two channels, panned hard left and right, with the right hand side's phase inverted 180 degrees. On an analog mixer, you can do this by multing the incoming signal, or by bussing the signal to two channels. If you don't have an analog mixer and have to do this in your DAW, you can record the figure eight signal and then copy the track to a second channel, reverse the phase on that one, and pan both channels, as you would on the analog mixer.
Once you have the figure eight in place as the sides, you introduce the mid mic on another track, panned up the center. The levels of the side signals should be identical. I personally mix the level of the mid mic so that when I sum to mono and the two side channels phase cancel, the level stays audibly consistent between mono and stereo. You might find that if you have mostly side signal, it might give you a more "psycho-acoustic" stereo image, but I'm always concerned about losing the balance of my mix in mono, so I shy away from that.
I tend to like the stereo imaging of M/S more than that of X/Y or Blumlein. It gives you excellent left to right separation, as well. Also, another advantage is that you don't have to have matching mics, as you do in X/Y or Blumlein. In figure 2., you can see my piano technique, where I'm using an AEA R84 ribbon for the sides, and a Neumann CMV563 with a M55K omni capsule as my mid. Other situations where I like M/S are on the horn of a Leslie cabinet or drums overheads. In those situations, I tend to use condenser mics or a stereo condenser mic. In figure 3, you can see a typical M/S mic array for condensers, with the top mic in cardioid and the bottom in figure eight.
If you haven't discovered this technique yet, give it a try and have fun with it. Try it with different combinations of mics, and see if you find something that works great for you. And if you can't seem to figure it out, visit us in the Use Your Ears forum, and ask us for some pointers.
figure 1:
figure 2:
figure 3:
Edited by J.J. Blair (04/28/07 02:13 PM)
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#1743719 - 04/30/07 08:52 AM
Re: What my M/S article was SUPPOSED to say.
[Re: J.J. Blair]
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BrianK
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Registered: 12/17/00
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Good thing you don't write about brain surgery, then!
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#1747761 - 05/08/07 10:23 AM
Re: What my M/S article was SUPPOSED to say.
[Re: BrianK]
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BrianK
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I used to use M/S all the time for piano - it gave a nice ability to "spread" the sound in different ways during final mix. Somehow that's completely different that spreading a stereo pair in and out with panners, especially when you want the Middle to be unusually low - can't do that with a stereo pair.
I never used it on drum overheads, but it seems it would work great for this, unless you want the washy splash of spaced omni's etc.
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#1749710 - 05/11/07 02:30 PM
Re: What my M/S article was SUPPOSED to say.
[Re: J.J. Blair]
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pfo
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Registered: 05/11/07
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Hi JJ, thanks for the helpful article on M/S micing.
I'm mixing a track right now that feels like it has hundreds of drum mics, mostly rooms and overheads (in reality it's probably more like 18), and I don't have any way to get more info on how the drums were recorded. My only real clues are the track names in Pro Tools: Room Mid, Room Side, Room 2 Mid, Room 2 Side, and the ones that I keep getting stuck on -- Ovr L, Ovr R, and Ovr Side. Did they perhaps mean Mid instead of Side? Did they mult the wrong mic?? Who knows? Adding to the confusion, the band has taken a crack at mixing already, and has inverted most of the drum tracks using the Audiosuite plugin -- how many times did they invert each track? I have no idea. So it becomes harder to tell what the original phase was. I guess my next step is probably to wade through the overcrowed regions bin and find the original playlists and reimport those, to figure out the original phase relationships of the tracks.
My question is, would Waves' MS matrix plugin achieve the same result as multing the side mic and flipping the phase on the right channel? Also, do you have any recommendations when mixing mysteriously labeled drum tracks? This is my first experience with M/S decoding so I'm not entirely sure what I'm looking for as far as knowing when I've gotten it "right". Not having been there for the recording process doesn't help much either.
Thanks for your help!
Pete
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#1749862 - 05/11/07 07:25 PM
Re: What my M/S article was SUPPOSED to say.
[Re: pfo]
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miroslav
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Also, do you have any recommendations when mixing mysteriously labeled drum tracks? This is my first experience with M/S decoding so I'm not entirely sure what I'm looking for as far as knowing when I've gotten it "right".
If you can't get exact info on what is what...and since the tracks have already been "stepped on" a few times...
...I would just use my ears.
If it sounds right...it is right. 
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miroslav - miroslavmusic.com"Just because it happened to you, it doesn't mean it's important."
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