Topic: recording acoustic musicians sitting in a circle

[cybergaloot]

I may have asked this before but don't remember any answers that stuck with me. I have friends who have an annual "pickin' party" where people basically sit in a circle and play. Here's what it looks like: https://www.youtube.com/watch?v=xvTnOsGA2nI How would you mic that? I have an LSD2 and thought about setting it to dual figure-8 patterns (Blumlien basically) and just setting it in the middle about 3-4 feet up.  I think the stereo image would be distorted (musicians sitting across from each other would sound like they were side by side) but without an ambisonic mic and a surround playback system I don't t see any way around that. I'm thinking that maybe a second set of cardioid mics on a stand about 7-8 feet tall split a couple of feet, aimed down and somewhat away from each other might help fill out the sound but not the imaging problem. 

Another thought would be to just set up a paid of mics on a stand just outside the circle aimed at the center.

Any thoughts of a better method?

[bryonsos]

Why not use an omni or two?

[cybergaloot]

I wondered about a split omni set up. The LSD2 figure-8 idea is basically omni with a bit of stereo separation. That has the advantage of using just one mic although it is a big brute.

I don't know when or if I'll get a chance to test this. That pickin' party is 200 miles west of me and I'm usually working 100 miles east of here on that weekend but I'd sure like to catch it one day. Its just that the set up issue has always bothered me.

[Bruce Watson]

I'm thinking that maybe a second set of cardioid mics on a stand about 7-8 feet tall split a couple of feet, aimed down and somewhat away from each other might help fill out the sound but not the imaging problem.

I'm thinking a set of omnis in AB30, on a stand about 7-8 feet tall, aimed straight down. Nothing you can do about the imaging problem, for stereo you have to reduce that circle down to a line (between the speakers) no matter what you do.

[cybergaloot]

Yep, surround would be the only way I can see to fix the imaging but it would be like you were sitting in the center of the circle, something most of us would never do. Mics on a stand outside the circle would be more like what  a listener there would hear. The problem with that the volume levels between the instruments would be a bit out of kilter. The closer or more directional instruments might be overly loud and the ones to one side might be quieter. Split mics in the center of the circle might have phase issues but I do not know that for sure since I haven't tried it.

Most of the time we record situations with the audience on one side of a line and the musicians on the other. The circle throws in a kink. Now that I think about it I sort of tried it once before but in that case it was a large circle  of people around a campfire but the musicians were clustered in one arc of the circle. I couldn't get between the fire and musicians so I set up on the other side of the fire. The results were not so good. lots of fire crackling with music in the background.

[voltronic]

Interesting problem.  Personally, I'd go with the center of the circle sound to capture all the players equally.  You won't get the front-to-back imaging unless you go with a surround setup, but one of these could get you a good stereo image without phase problems, using just two mics:

- Omnis on a jecklin disc
- Omnis on a dummy head
- PZMs mounted back-to-back on either side of a plexiglass sheet
- narrow spaced omnis as Bruce suggested

I'm not sure I'd go with any of these mounted on very tall stands, because then I feel you would lose some of your stereo separation created by the boundaries / spacing between the mics.  You don't want the recording to sound like someone standing on top of a tall ladder above your circle.

[cybergaloot]

I hadn't thought of using a jecklin disc. Interesting!

[Gutbucket]

Jecklin works great for this in  the center of the circle right at shoulder level.  Gets everyone equally all around the circle with really nice imaging.  Slightly spaced 180 degree omnis work without the baffle too, it's just more nicely defined with the baffle.  Down low like that gets it nice & intimate sounding and the players bodies really help block noise from talkers outside the circle.  If it's not a cocktail chat scene outside the circle and there is a second orbit with additional players or people singling along you'd like to pick up more of, then you can go high with a more typical near-spaced config pointed directly down into the center of the circle.  If one player is the obvious anchor, you might tilt that their way a bit.  If you need to use cardioids down low at shoulder level I'd arrange those 180 degrees coincdent, but omnis will probably work beter.

[F.O.Bean]

I would do something like what Schoeps sells and do a double ORTF or something like that! Its just one pair of mics facing forward, and one pair of mics facing backwards. Then you could just sync them up and do a matrix in post. Should sound pretty cool too. Its just a 4 channel surround setup without an ambisonic mic

[cybergaloot]

I guess I need to make myself a Jecklin disk sometime. I don't if or when I'll ever make it over to the pickin' party I'm thinking about but those boys can play! If you know who Guthrie Trapp is, he is basically a former protege of theirs.

[weroflu]

blumlein renders sort of surround sound somehow with only two mics, not sure how it does it but it does it.

[cybergaloot]

blumlein renders sort of surround sound somehow with only two mics, not sure how it does it but it does it.

http://en.wikipedia.org/wiki/Blumlein_Pair

Blumlein is essentially four coincident omni mics but two with flipped polarity.

[cybergaloot]

blumlein renders sort of surround sound somehow with only two mics, not sure how it does it but it does it.

http://en.wikipedia.org/wiki/Blumlein_Pair

Blumlein is essentially four coincident omni mics but two with flipped polarity.

Here's a really good video of how they get the various mic patterns but I don't remember if it included Blumlein: https://www.youtube.com/watch?v=ihAG6cMpUlY&list=PLvOlSehNtuHv98KUcud260yJBRQngBKiw

[Gutbucket]

I guess I need to make myself a Jecklin disk sometime. I don't if or when I'll ever make it over to the pickin' party I'm thinking about but those boys can play! If you know who Guthrie Trapp is, he is basically a former protege of theirs.

You can make due pretty well by just setting up two omnis at shoulder height, spaced about a foot apart or so on a mic bar, then draping a jacket or sweater or something over the bar between the mics.  Might help to mount the mics upside-down on the bar so they hang beneath it, so the draped jacket or whatever is high enough to properly baffle them.  As long as whatever you put between the mics effectively blocks the sound from arriving from the opposite side, yet both mics can still 'see' the performers to the front and back of the plane between the mics it's good.   It's also somewhat casual and less imposing than a fancy disk, which might make the performers more relaxed.  I like shoulder or chest height because it is about equidistant to both the voices and instruments, so both are clear and close and neither is over represented, and it's low enough that the performers can easily see each other over the top.  That's far less imposing than something at head height blocking the view and potentially killing the vibe, or even up high looking down on things.

[Gutbucket]

I would do something like what Schoeps sells and do a double ORTF or something like that! Its just one pair of mics facing forward, and one pair of mics facing backwards. Then you could just sync them up and do a matrix in post. Should sound pretty cool too.

A common setup for recording four channel ambient surround atmosphere material is the IRT cross, which is simply four cardioids (or supercards using less spacing between mics) arranged in a cross shape pointing outwards.  http://www.schoeps.de/en/products/categories/irt-cross

If mixing those four channels down to 2-channel stereo, you have two basic choices.  I'd play with routing them both way and go with whatever sounds best.  Looking at the cross from above and going around the circle  of microphone channels you could route the four mics either:

Left, Left, Right, Right
-or-
Left, Right, Left, Right

The first would provide imaging somewhat more like Jecklin baffled omnis- the players on one half of the circle would image Left, and the other half would image right.  Because of the cross-talk between adjacent mics on each side getting mixed together, listen for potential comb filtering problems.

The second way would image somewhat more like Blumlien, with quadrants of the circle imaging Left/Right, Right/Left, Left/Right, etc.. all the way around. The difference is there would be no reverse polarity quadrants as with Bulmlien.  I suspect the second way would work best, but you never know until you actually try it.

[Edit- fixed link. The IRT cross is symmetrical and doesn't favor any particular direction which may be most appropriate in the center of the circle.  Double ORTF is similar, and could be mixed similarly, but isn't symmetrical and wouldn't have as symmetrical a playback image of all the musicians arranged in a circle.  It's meant more as a forward/backwards oriented surround recording setup- basically a surround extension of typical forward facing ORTF stereo)