Old 04-20-2021, 10:31 AM   #1
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Default Mid/Side Recording

I decided to try out some mid/side recording the other day. I got myself a cardioid (I'm pretty sure) condenser mic for my center channel, and a figure 8 for my sides, and doubled the figure 8, and panned hard left and right. And the results are pretty interesting. But, I find that my mono signal, sounds very mono when soloed, and my figure 8 stereo signal sounds very level in stereo field when soloed, but when I combine the two, the combination seems panned a little to the left. If I invert polarity of the mono mic, it sounds very much to the right.

Is this because of my mic placement or something perhaps? Did I do something wrong? Or is this normal? Seems like it would be an undesirable way for this to work to me.
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Old 04-20-2021, 11:18 AM   #2
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I decided to try out some mid/side recording the other day. I got myself a cardioid (I'm pretty sure) condenser mic for my center channel, and a figure 8 for my sides, and doubled the figure 8, and panned hard left and right.
When you duplicate the figure 8, don't forget to invert the polarity (on the one that you pan hard right). You shouldn't invert the polarity of the "mid" mic, only the right-hand channel of the figure 8.

Also the capsules of your mics need to be as coincident as possible and the sides of the figure 8 need to be exactly 90 degrees from the mid.

A simpler approach is to use the free MSED plugin from Voxengo.
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Old 04-20-2021, 11:37 AM   #3
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I think I did all of those things, but I still notice a bias to one side when I put them all together.

I tried inverting the other side of the figure 8 instead, and still got the same result, but on the other side.

I had one condenser which was sort of like a shotgun style mic. That was the center channel, and I used an AKG c414 as the figure 8.

Maybe I placed the figure 8 wrong? I was thinking one side of the 8 would shoot out the front and the other side would shoot out the back, and that I'd have nulls on the edges of the microphone, but maybe that was a false assumption? But, it looks right, when looking at this

Is there supposed to be a bias like this?

So, the c414 is kind of a flat square almost. I pointed the flat sides perpendicular to the guitar, and then I took the shotgun condenser and set that along the top of the c414, pointed straight at the guitar.
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Old 04-20-2021, 11:41 AM   #4
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Just a sanity check that the Fig-8 mic is aiming L/R in relation to your position. So, it's the front/back of the mic itself, but the mic is turned 90 degrees in relation to the source it is recording. That's why it's called "sides".

Actually, your last sentence makes it sound like you have it correct. Just remember M/S is very directional up close and works better with a little distance. Otherwise, it will pick up the tiniest L/R movements when playing or even left vs right hand or sound "crooked" if too close. When I was doing a lot of singer/player recording with M/S a couple years ago, I didn't like it until I was at minimum 20+" back from the mic, if not 30" YMMV.
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Old 04-20-2021, 12:39 PM   #5
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I don't know about the C414, but lots of figure 8 mics have a level difference between front and back and need a bit of level correction.

Could that explain the bias?
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Old 04-20-2021, 01:11 PM   #6
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I don't know about the C414, but lots of figure 8 mics have a level difference between front and back and need a bit of level correction.
That seems a likely culprit: most multipattern condenser mics and even dedicated figure 8 condensers don't have symmetrical pickups in figure 8. As far as I know the only condenser that truly does it is the Sennheiser MKH 30. Ribbons usually do a better job in that department but you work with what you have....
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Old 04-22-2021, 09:08 AM   #7
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I don't know about the C414, but lots of figure 8 mics have a level difference between front and back and need a bit of level correction.

Could that explain the bias?
I don't think so, because the c414 on its own sounded even in the stereo field. And the other condenser sounded straight down the middle. It was when I combined them that I got the bias, and that might be because of some phase cancelation happening. It may very well be that it's just because standing in that spot, there would be a natural bias like that. But you don't really hear it when each mic is alone, since it's just one mic, and not two, so there's no real way to have any bias there. But once you mix them, then it adds that sort of possibility for 3D, and the phases cancel out to give the directional information. This is my guess so far, anyway, and going with what karbo said, I think that makes good sense. When you're further off, I could see this being less obvious, but up close a real factor.
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Old 04-20-2021, 12:42 PM   #8
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Originally Posted by karbomusic View Post
Just a sanity check that the Fig-8 mic is aiming L/R in relation to your position. So, it's the front/back of the mic itself, but the mic is turned 90 degrees in relation to the source it is recording. That's why it's called "sides".

Actually, your last sentence makes it sound like you have it correct. Just remember M/S is very directional up close and works better with a little distance. Otherwise, it will pick up the tiniest L/R movements when playing or even left vs right hand or sound "crooked" if too close. When I was doing a lot of singer/player recording with M/S a couple years ago, I didn't like it until I was at minimum 20+" back from the mic, if not 30" YMMV.
I agree... a bit of space goes a long way to making the m/s technique far more flexible. You're dealing with more room at that point too. I like that for singer-songwriter style recordings. It's one of my preferred ways to capture.
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Old 04-22-2021, 09:05 AM   #9
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Originally Posted by karbomusic View Post
Just a sanity check that the Fig-8 mic is aiming L/R in relation to your position. So, it's the front/back of the mic itself, but the mic is turned 90 degrees in relation to the source it is recording. That's why it's called "sides".

Actually, your last sentence makes it sound like you have it correct. Just remember M/S is very directional up close and works better with a little distance. Otherwise, it will pick up the tiniest L/R movements when playing or even left vs right hand or sound "crooked" if too close. When I was doing a lot of singer/player recording with M/S a couple years ago, I didn't like it until I was at minimum 20+" back from the mic, if not 30" YMMV.
Oh ok, this might be exactly what it was. I was indeed pretty close to the mic, like maybe about a foot away.
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