ORTF. Is it pizza?

O

Ora

New member
I'll be recording a (hobbyist) choir in a few weeks.
First, we'll make a test recording in the rehearsal room. Probably a quite bad place. Then if they like the results we are going to make a full CD project later in an acoustically better place.

Choir setup is:
about 30 people
back row: bass voices left, tenors right
front row: sopranos left, altos right
back row stands taller than the front row.
Just voices, no accompaniment.

Available condensers:
2xNeumann KM184
2xAKG C4000B
1xNeumann TLM103
2xRode NT1

How to place the mics. I was thinking of capturing left, middle, right from a shortish distance and also recording the ambience (which might be very bad) with a wide A-B stereo pair. Front mics: KM184, TLM103, KM184. Ambience: C4000B pair.

I have never recorded choirs. What say you? What mics in what position? At what distance? At what height? Pointed towards what?

I will have about 1 1/2 hours to experiment with mic positions while the choir is practising. Should be plenty enough.

Best regards
Ora

PS. ORTF. Could someone explain this mic technique to me?
 
you are asking for phase problems with so many mikes

I would go with the 2 AKGs, capsules touching,angled apart 45 degrees at front of house about 10 or 12 feet high.There is a mike theory (in recording acoustic sources)that says whatever the size of the sound source being recorded,place the mike about that distance away.For example,any uncentered placement of mikes on a choir will pick up more of the sopranos or whatever.Back up untill the "bloom" of the sound appears.The touching,angled approach above will give stereo without the phase problems.
regards
Tom
 
Do you have an orchestra playing with your choir?

To me is seems that the KM184 in an ORTF setup would be enough. (or you can play around with different stereo setup to see what you like most). For a choir of 30 people it seems to me like it would be enough.

I recorded choirs of 100 people and for that I used 2 stereo pairs (on left and one right). You could also try to mike different sections of a choir with omni mikes, but you don't have them in the list (KM183 would be good), but again for a choir of 30 people I don't think it is needed.

So now about ORTF. It was invented by the French Radio and Television Organization and it uses a matched pair of either cardiod or omni mikes. They make an angle of 110 degrees (55 degrees on each side of an imaginary middle line) and the capsules should be spaced by 17cm (about 7 inches). You can get a cheap AKG adapter (that also allows for other stereo configuration) for about $15 or a more expensive shure device for about $45.

I use ORTF a lot (sometimes XY) and to me it sounds really good.

You can also try the following improvement to the ORTF technique that I read from a famous sound engineer for classical music and he used it to record the Dallas Symphony. Place an omnidirectional mike between the two mikes of your ORTF pair (assuming you used cardiod mikes). In ORTF the cardiod mikes are not very good for the bass frequencies, and so the omni will compensate. Depending the room, choir, ... I would set the omni around -6dB.

ORTF also works well with orchestra, but for some big orchestra, spot mikes are needed.

And then depending on the size of the room I would put the pair about 10 to 15 feet high at about 10 feet back from the choir. Move it depending on the sound (too present or distant, or too much reverb). In more than 1 hour you'll have plenty of time to pick a nice spot. (I always start by walking around the place to see where it sounds good and start from there).

I hope that answered your question.
 
Tom, Dolphin, thanks!

Tom, you are saying a 45 degree X/Y?
I searched the web and found this ORTF picture:
http://www.oade.com/tapers/micsetuportfzoom.html

Anyway, becayuse I have the time I'll try both X/Y and ORTF.

BTW dolphin, the AKG C4000B has omni pattern. I'll try that as the "center mic" addition to the ORTF.
A further (probably stupid) ORTF question:
Watching from behind the mics one points left and one points right. Should they be panned accordingly? And pan the omni at center?

So that takes 3 tracks. I still have a C4000b, TLM103 and 2xNT-1 left. As the recorder has 8 tracks (adat XT20) I would like to test the rest of the mics too.
Any suggestions on how to place these. Especially C4000B and TLM103, I don't think the NT-1s will be of any use (I'll try them anyway).

For preamps I have to use a Mackie VLZ Pro mixer because that's all I have.

All the best
Ora
 
Ora,

Yes, Pan one hard left and the other one hard right. If the stereo image feels too big then change it a little. But hard left and right should work fine. Then the omni at center. If you use more than one pair, then you need to pan them differently of course.

I don't know the AKGC4000B, but I would try to use a small diaphragm mike (which it may be). I usually use KM184 and 183.

Otherwise in X-Y configuration, the mikes have an angle of 135 degree (and you use cardiods). In Stereosonic configuration, they have an angle of 90 degree, but this time you use bidirectional mikes.

For the extra mikes, here is another thing I tried for classical music when I record in a very very nice hall. To get more of the ambient sound, I put two mikes further back. And sometimes facing the other direction (facing the back of the room). If the acoustic is not so great, forget about the idea.

VLZ Pro preamps are much better than the ones in the old Mackie. So I think it should be ok.

Good luck and have fun!
 
Thanks folks!
C4000B is a large diagphram and the only omni I have. I'll use it.

One can always hope for some luck. But I'll definitely will have some fun!

Regards
Ora
 
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