360 degrees Stereo Recording - What Mic Setup??

Hello, Im planning to make some recordings of an old men choir that usually gather around in a circle and sang along... I would like to make a "stereo" setup in order to get them nice and evenly...
I dont have 3 omni mics so i would do the Decca Tree setup, and also, the circle sometimes dont get 2meters from side to side, so no space enough to this setup...

I have for this recordings an AKG C414 B-uls and a pair of Ck91 cardioid...
I thought of MS with C414 as Side mic and 1 CK91 as Middle mic. Can i add the #2 Ck91 pointing back? I think this would need to be phase reversed to match Middle Diagram polarity, but this would mess things up with the Side mic right?
Maybe i would do better with the C414 in omni by itself, but i would definitely miss the stereo imaging... even if not 100% accurate..

Any help is highly appreciated!
All the Best,

Hi,

    you will only hear them around you if you have quad(lcrs), 5.1, 7.1 etc . . . .



    I am absolutely no expert in more than two dimensions(ie stereo!), but i think you could use, say two cardiods back to back as leftright and 414 in fig 8, with front phase and rear antiphase . . . . .


      anyone . . .


      ANdyP

I've always wanted to try a Blumlein pair, do you have two mics that can do figure 8?



Some day I'll buy another AT4050 just for this...

surely he can do this (in effect) with 2 x cardiod and 1 fig 8 . . . . . better if all transducers are the same, but .  . .



  CORRECTION . .. no he cant. Blumlein is not facing NorthSouth, EastWest,


    but NW SE, NE SW


    DOH!

hmmm im definitely not gonna get a pair of 8 figure mics...
How do you end up processing the Blumlein setup?
(L+R)+(inverted phase+pan L+R)???

i'd put a binaural mic setup with a dummy head there... get the same sound as the conductor.

it'd be lovely in some headphones.

no pair of 87s in fig. 8?
a couple of ribbons?
blumlein is a great option,
wut? no calrec soundfield mic?
that would be another nice option.

what about a M/S pair. then you can control how much or how little stereo width you have.

Also some room mics blended in would work great. Maybe a Stereo Set up for the choir and then some room mics to capture performance hall.

is not of any help but we are having some choir sessions on location next week and our set up would be 2 Soundfields ST250s with a couple of 87s for outriggers and another couple of 87s or 414s for spots.... let's hope... 

...but I think I would go with puchos812's suggestion in your case.

Pucho's idea is probably the best. But if you only have access to the mics that you said in your first post  you could go for the C414 in omni with the cardioids as a spaced pair.

Do they stand in a full circle or semi-circle? As an ORTF setup might give you quite a nice stereo image too.

Alternatively if you have time you could just have a play around for awhile and try different setups. Maybe even just point one cardioid at each half of the circle.

Rob

In a good room, a single figure 8 centered and above them might work.  I know its not stereo but it seems to me that any stereo setup in that situation could be confusing.

pedrocruz said:

hmmm im definitely not gonna get a pair of 8 figure mics...
How do you end up processing the Blumlein setup?
(L+R)+(inverted phase+pan L+R)???

Click to expand...

I'm not really sure since I've never recorded that way, but I think you just pan them hard L and R...

Anyway, that brings me to my next suggestion, Mid Side.  I use Mid Side recording on everything, even mono sources.  It's a beautiful thing.  In your case I'd just use an omni pattern instead of a cardiod for the mid, and you should be good to go.  And if you don't like it, you at least have a mono omni recording to work with. 

Soundfield mic.

Record B-format output.

You can subsequently generate ANY NUMBER of completely phase-coherent outputs, or any pattern, pointing in any direction, and at any angle of elevation.

Blumlein is wonderful, SO LONG AS THE SOURCES ARE IN FRONT OR BEHIND. -Anything to the side comes out as "out-of-phase", since it s picked up in the positive polarity lobe of one microphone, and the negative polarity lobe of the other. -Beware... -Here be dragons.

If you don't have a Soundfield, you can either DIY an A-format mic and build an A-to-B encoder, or build a native B-format microphone, as I and a couple of other people have done.

Keith

I definitely dont have a Soundfield
So far just Ck91x2 and C414 buls... unfortunately...
But im starting a Diy electret mics... Not brilliant but usable...

If they stand in a circle, I would be tempted to try it with all three mics placed
coincidentally in the centre, each angled 120 degrees apart and arranged with the 414 (in cardioid) pointing toward the bass section.

This should cover the whole area, is guaranteed to be phase coherent, and if you pan the 414 in the centre should provide a pretty good stereo image.

The key will be in how you get the singers arranged. 

thanks MagnetoSound,

All replies were helpful, if i manage to do the electret mics in this site http://www.moosapotamus.net/THINGS/mics.htm ill try to use them, otherwise ill use your setup i believe...
Although the singers are just old man from the countryside so no much "choir" rules like making vocal range positions etc... it is extremely free standing. songs like this one http://www.youtube.com/watch?v=nv--2UBZx_M i found this randomly on youtube, but just singing, no "guitars"...
This is our blues...

Those Moosapotamus mics as shown are low-output and quite noisy... They're also very Omni, albeit with a slightly more directional HF. -With that in mind, using close or coincident techniques will almost certainly result in disappointment... You'd have to space the singers out and use the mics spaced in order to realise any particularly useful separation.

Keith

SSLtech said:

Those Moosapotamus mics as shown are low-output and quite noisy... They're also very Omni, albeit with a slightly more directional HF. -With that in mind, using close or coincident techniques will almost certainly result in disappointment... You'd have to space the singers out and use the mics spaced in order to realise any particularly useful separation.

Keith

Click to expand...

I see, ive just setup the circuit in a breadboard using BC556B and i couldnt make it work... This transistor was given to be as being an alternative to the 2n5087 present in the circuit but with more gain then 2n5087 and with emitter collector pins swapped...

Keith, do you know any circuit that you would recommend for Panasonic WM61-a?
Cheers!

The problem is that the WM-61a limits your absolute noise floor. -For loud sources it can be quite usable, but if you're doing a capella vocals for example, it will define your noise floor, unless you're in a fairly 'noisy' room.

Look at this one:

http://www.directap.com/Microphones.htm

There are a few options there. They're all noisy... -I'm not sure that my standards are all that high, (sure, I know that I'm fortunate enough to own some great microphones and preamps) but I think the only time I could use them at any distance would be for something like a brass band, end even then, I'd have to make sure that there's to be no quiet solo sections slipped in there...

By all means build them; they're inexpensive and good for playing with. -Also, the circuits use largely common components: they're all basically the same circuit after all, with varying degrees of simplification from the (presumed to be the original) Schoeps circuit.  -It's just that if you're pressed for time and betting or hoping that this will be a good all-round mic, I have to say that I've never had any widely usable results in terms of noise floor. -In front of a loud Guitar cab, noise wouldn't be an issue at all... but then I'd probably be reaching for a different mic for that job anyway.

It depends how you value your time, and how pressed for time you are. -If you're looking for things to do, have the time, and aren't depending on a usable result, I say go build a few Panasonic variants... but if you're pushed for time or component cost, this might not be the answer. -Personally I think this might be a good time to borrow a couple of mics with a view to buying something if you're going to do more in the future.

Keith

I ended up designing and building my own B-format mic some time ago...













It worked pretty well, and the large diameter capsules (they're Peluso K67's in the pictures, but I have a pair of Neumann K67's to swap in there, just as soon as I get some new mounts fabricated) ensure a low noise floor... but it's not so fabulously suited to distance work... however, it sounds FANTASTIC up close!

Keith