Need some guidance on micing a live choir & other stuff

[True North]

OK - so my daughters school puts on performance assemblies about twice a year. They don't have a sound system and end up using a DJ to do the musical cues and sound . He's actually a nice guy but he has no idea what he is doing nor the right equiptment to properly do the job.

Anyways, my wife is part of the parent council and just as they are discussing the purchase of a school sound system, she pipes in about my experience and background. Now I have mic'd tons of bands but I have never tried to mic a live choir or group ensemble before.

Could you give me an idea of some mic types, mic positioning/arrays, polar patterns etc...

Think of your typical school stage in a gymnasium - on the stage there are vocal groups ranging in size anywhere from 6 kids to 50+.

I am sure this is a walk in the park for some of you but I am looking for some guidance, thanks

[Remoteness]

I got to head out for a bit but, in the meantime try these threads out for size...

The "Choir" search list.

This should keep you busy until someone chimes in.

[joelpatterson]

The simplest thing to do is put an ORTF set up on a pole, about nine feet back from the choir and nine feet up in the air, kind of right over the head of the conductor, who is hopefully standing front and center, leading the choir.

The nicer the mics and the nicer the pres, the better it all will sound.

That really will do it, but if you wanted to go overboard a little, you'd have a pair of omni's spaced wide to the sides. Even more overboard, you could have a set behind the choir to add detail and realism.

More than that, you're heading into overkill territory. I do alot of orchestra/choir stuff, and quite honestly, six mics will take care of it.

Oh, and then you could put spot mics on the soloists and....

[True North]

Thanks guys.

I hate to sound like a moron but oh well here goes,...... what does ORTF stand for?

[bishopthomas]

It stands for two cardioid mics, elements 17 cm apart, at a 110 degree angle.

[vinnyf]

ORTF = Organization Radio-Television Francais - they invented (or at least popularized) the technique

[joelpatterson]

Now to get really really REALLY picky...

The ORTF spec has the mics splayed out at 110 degrees from each other, 17 cm apart... but for some reason I've ended up prefering the NOS spec (the Dutch equivalent) which calls for the mics to be set at 90 degrees and 31 cm apart.

Maybe I'm just inherently simple-minded... but the idea that the mics are perfectly "squarely" opposed to each other means that any sound hits each mic somewhere right exactly between two squarely opposed poles... I dunno, just seems better maybe. Probably doesn't make a dime's worth of difference.

The whole beauty of either approach is that you get an accurate, stereo picture, with minimal fuss.

[d_fu]

Originally Posted by joelpatterson

but for some reason I've ended up prefering the NOS spec (the Dutch equivalent) which calls for the mics to be set at 90 degrees and 31 cm apart.

"Now to get really really REALLY picky... "
30 cm. Thirty. Not thirty-one. It makes a big difference...

but the idea that the mics are perfectly "squarely" opposed to each other means that any sound hits each mic somewhere right exactly between two squarely opposed poles... I dunno, just seems better maybe. Probably doesn't make a dime's worth of difference.

Don't think so... There's just more channel separation by mic distance and less by angle. Some people would argue that such techniques are slightly flawed in principle because a lot of sound hits the mic off-axis (where the frequency response of cardioids may not be as even).

NOS/ORTF and DIY derivatives thereof are quite easy to use indeed and produce good results... A setup like this in front of a string quartet in a reverberant church made the musicians, who were worried about excessive ambience, very happy...

[ghellquist]

Correct me if I am wrong, but I read the original question as how to "amplify" the choir, not how to record it?

I´ve done a bit of recording of unamplified choirs. ORTF is definetlely one way to do it although there are many different solutions. But I would never use ORTF as a feed to the PA. My guess is that for PA I would use overhead cardioids if possible, say 4 or 6 to cover the choir. Only a guess though, never done it.

Gunnar

[d_fu]

Originally Posted by ghellquist

Correct me if I am wrong, but I read the original question as how to "amplify" the choir, not how to record it?

Possibly...

I´ve done a bit of recording of unamplified choirs. ORTF is definetlely one way to do it although there are many different solutions. But I would never use ORTF as a feed to the PA. My guess is that for PA I would use overhead cardioids if possible, say 4 or 6 to cover the choir. Only a guess though, never done it.

Me neither, but it sounds like a good approach...

[Jim vanBergen]

Please specify if this is to amplify the choir, record the choir, or both...
we have copious experience and ORTF is great for recording...not gonna if you're amplifying.

Best,

Jim

[Andrew B.]

It sounds as if you are talking PA/live sound reinforcement. The problem with kid's choirs in this context is that they don't have great volume normally. Which of course is why they need reinforcement. The general principle is to use cardioid condenser mics and as few of those as possible. It becomes harder when the size of the group you are miking keeps changing too!

A starting point for a choir of up to 50 would be to arrange them in a block 3 to 5 people deep, ideally with those at the back raised up from those at the front (older kids at the back, in your case - staging for adults). Then use just one pair of good quality small diaphragm cardioid condenser mics positioned about 2 feet in front of the first row and 2 feet above the heads of the rear row of singers. The mics chould be spaced well apart. See the Shure notes here:
http://www.shurenotes.com/how1/how1_choirmic.html

Andrew

[MichaelPatrick]

IMO,

The simplest and most reliable mic technique for both recording and amplifying small or mid-sized ensembles is X/Y -- a coincident matched pair of small capsule cardiod condensers like Rode's NT4. You can also make an X/Y stereo main with any two cardiods if they are alike (a matched pair is ideal). This approach rejects rear sound and it produces a phase-coherent signal that you can even mix to mono for sound reinforcement. If some choir memers are too far left or right of the main X/Y pickup you can put a cardioid near each end to get them all. But then you may as well consider three spaced cardiods. Spaced omnis also work well if you're not amplifying. Placement of omnis is trickier, though, because they grab alot more ambience. Another issue is that spaced mics (cardioids or omnis) don't present a well-defined soundstage on playback.

For me the most reliable technique for recording is Blumlein -- two figure-of-eights. Once you know how to set them up you can get good recordings even in rooms you don't know much about. The rear lobes pickup ambience and the sound stage is usually very good. The danger with Blumlein is getting too close so that some of the front sound from the extreme left or right side will be picked up by the back side of mic (remember, the pattern is figure-of-eight). When that happens some of your frontside signal appears in the opposite channel 180% out of phase, and it very quickly destroys any soundstage you may have had. If you can avoid that problem, Blumlein is probably the most reliable technique for getting a good recording with minimal fuss. If you don't have the mics for Blumlein, I'd go with ORTF. It's also quite forgiving. It doesn't pickup in the rear, but it doesn't mix to mono. If you try, the tone is damaged by phase competition between capsules, comb filtering. That's why it's not good for PA amplification.

If you have a good stereo mic technique, extra mics mixed-in can then take a recording to another level by widening the soundstage or adding ambience and air. I think a good stereo main-mic is the best foundation to build on, and it can even work all by itself in most cases with good placement.

[Jim vanBergen]

It's all physics (that's PHYSICS, not PSYCHICS) when you amplify a nearby microphone.

The gear plays a large amount of what you can do. What type of speakers are available? Are you renting? Do you have any idea what the school owns, or what the DJ brings?

Most DJ rigs are designed for PLAYBACK and a super-close mike'd VO mic. For choir reinforcement, you really want a very well contsructed speaker that has a consistent polar pattern (such as 45x45, 45x60, 60x90, etc) you DO NOT want anything wider than 90degrees horizontal, especially if you are bringing in "speakers on sticks" and putting them up on a stage or in front of the stage the choir is on.

The reason that XY, ORTF, and M-S don't translate well to amplification is that the mics are often too close to the speaker and the speaker output pattern overlaps with the microphone pickup pattern, which , boys and girls, equals FEEDBACK. Especially when we're talking about amplifying a choir, which is hard to do. You really want some condenser mics at a distance to capture an even sound, but dynamics are much more smooth and have less sensitivity which can help you OR hurt you depending on the situation.

Normally for a choir I'll use small diameter condenser CARDIOID mics on stands at about 7', aimed at a 30degree angle to the choir, from no less than 5'. I have also used supercardioid pattterns (tighter focus, picks up fewer people, has better rejection from sides/less feedback potential). I have also resorted to dyamic mics in a closer formation. Many times you have to work with the choir director and use mics PER SECTION (S-A-T-B) to have a nice blend.

Does any of this help?

Jim

[True North]

Originally Posted by ghellquist

Correct me if I am wrong, but I read the original question as how to "amplify" the choir, not how to record it?

Bingo - First and foremost I need to amplify this, not record it. I may decide to record it as well but that wont be the first goal

[joelpatterson]

In that case, forget everything I said.

You're going to need to get pretty close to your singers, and feedback is going to be the looming headache. If there's any way to try this out at a rehearsal, you will find out exactly what the parameters are.

[True North]

Thanks for the replies guys, but now that we have confirmed that I want to amplify the performances I just wanted to see if I could get some more suggestions.


I know that feedback is going to be an issue and I was planning on making sure that the speakers were well ahead of the live mics.


Still need some direction on mic selections, positioning etc..

Thanks.

[Jim vanBergen]

I'd look at quality cardioid condensers, like Neumann, Earthworks, Sennheiser, but would not sneeze at Shure SM87s either...

I'd look at no LESS that 7' height, no more than 6' from the singers, perhaps closer, focusing into the center of the choir. If you can pickup the front and back rows as cleanly as you can the middle, you're in a good starting position. Are they on RISERS?

Any idea how many rows? How many singers per division (SATB?)

jim

[bishopthomas]

What is your budget? Are you using the DJ system as the PA? Does he use a mixer and is phantom power available on it (you'll need it for condensors)? If you need to rent a PA and/or other gear besides microphones is your budget for the entire package? Finally, maybe you would be better off hiring someone to run sound alongside the DJ. As you said, DJ's aren't really the type of people who know how to mix live sound.

[True North]

Originally Posted by bishopthomas

What is your budget? Are you using the DJ system as the PA? Does he use a mixer and is phantom power available on it (you'll need it for condensors)? If you need to rent a PA and/or other gear besides microphones is your budget for the entire package? Finally, maybe you would be better off hiring someone to run sound alongside the DJ. As you said, DJ's aren't really the type of people who know how to mix live sound.

I plan on renting some peices of gear for the live show. I will probably pilfer through my mic collection for now to get the job done and than reccomend some mics for them to buy later. The board would absolutely need to have Phantom power as I plan on using condensors. I will also be reccomending some PA gear for them to buy as well. I was thinking that they should probably hire a FOH person instead of the DJ altogether.