Monday, August 27, 2012

Dear SNR - Choir Mics

I got a letter from one of our friends in Germany (in the middle of the night, we never close!) asking about an upcoming gig.

Hey Jon,

I have a gig coming up that involves a kids choir up on the same stage with a rock band.The first rehearsal turned out not so great.

With you doing church sound and so on, I figure you're a lot more experienced with that type of stuff. Can I hit you up with some specific questions? I think you might have some great recommendations concerning mics, stage layout and so on?
Thanks,
Eike

Of course you can Eike! And so can anyone else. The truth is, we don't get a ton of mail here so if you write in with a question, unless it get's lost in the junk filter we'll get right on it. As always I'll encourage you to get on ProSoundWeb.com and other great sites that have loads of articles about every subject you could ever imagine. A lot of what I know today started out as a kernel of knowledge gleaned from the web.

But in this case I'm going to tell you to save that for another time and I'll just tell you the way that I like to mic a choir.

Hanging choir mics are great. Installers love to sell them to venues. The truth is though, they're great for making a nice recording of the school Christmas concert and not much else. I've complained in the past that omnis are not the sort of thing you want to turn on when you're trying to catch actors in a musical or a choir or anything else you want to put through the PA. Then someone will respond and say, "Oh, no. You've got it all wrong, they're directional all right." Well, they're not directional enough. Unless you're in a perfect environment, putting garden variety hanging mics in the PA is a recipe for disaster.

My technique is as follows. Throw a pencil condenser mic like an SM81 or AKG 430 up as high as you can get it on a boom stand and do that about every eight to ten feet along the front of the chorus. The reason for putting them high is that you're able to get them more equidistant from each singer when they're way up there. The spacing can vary a little. The idea is to use the three to one mic rule somewhat. That makes sure that each mic isn't picking up too much of what the mics next to it are picking up and making phase issues.

The height and aiming are even more important if there are wedges in front of the singers. Stage bleed from other instruments on stage is nothing compared to the hell of the monitor mix folding back into the choir mics. I haven't had to do it recently but in the past I've resorted to blocking them up to be near vertical or using pole speakers with the poles as short as they'll go so that the horns aren't blasting right up into the mics.

Once you've got your mics selected get them into the console and do some serious EQing on them. You could write a whole article about how low frequencies sum in the most incredible ways when using multiple mics and you should look that up if you care to know the particulars. If not, just low pass them where you think it's reasonable and then use the low shelf EQ as well. Just trust me on this, you'll save yourself loads of heartache with low end feeding back and you'll get more gain out of them.

Then bus them down to a group or pair of groups if you need things in stereo and slap some compression across them. I mix a choir on stage with a rock band about twenty weeks out of the year and I've messed around with different settings. I feel like I've had the best luck with higher ratios (6:1 or so) and dialing down the threshold until I'm not seeing more than six to ten dB of reduction. Your results will vary. The goal is to be able to turn them up loud enough to capture quiet passages even when the band is still churning away, without having the big peaks take over the mix.

I've messed around with gates and while I'll use them for insurance I'll usually have the threshold extremely low. That's just to prevent feedback from happening during a speaking part when everything else is quiet. Expanders might work better since they just dim things a bit when below the threshold and sound a lot more natural than a gate slamming open and shut.

That's my two cents Brethren of the Knob and Fader. Some of you will be amazed at my audio prowess, some of you will think me a fool. Let's hear about it in the comments section, as well as any ideas you might have on how Eike can nail his upcoming gig.

6 comments:

  1. Hey!

    Thanks a lot. I'll re-read this a couple of times and take copious notes. If something's still unclear then I'll ask :)

    There's lots of great info in the article! I already did some of it, but there's plenty of stuff I'll try out.

    One thing that I haven't really figured out though: where would you place the choir? And how? Does an "assymetrical" setup (let's say: band stage left / choir stage right) make sense? How to set up the choir: lump registers together? Sort the kids by size?

    Thanks again! And to anyone who wants to chip in, feel free to do so :)

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    1. Asymmetrical is a great idea and that's how I run my choir. It lets me back them up in a quieter part of the stage and the mics are pointed into soft goods (curtains).

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    2. just wanted to report back real quick: everything went nicely!
      thanks for the advice, i put it to good use, i think :)

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  2. Well, the band had a certain stage layout in mind, which they didnt want to change, so the assymetrical setup had to go. The choir was positioned right in front (downstage). I put up 2 SDCs at the very edges of the choir, slightly pointing down and in (and away from the PA) and 2 SDCs 6-7 feet in from the "edge mics" pointing right into the choir. Coverage was pretty good that way, I think (stage width was ~ 7 meters / 22 feet). Band was up on a riser (weird choice maybe, but worked pretty nice actually) I put up sidefills for the band, which worked pretty nice. I had those pointed in at the band and away from the kids.

    The mics went thru a submixer where I hipassed and panned them (hard left, center, center, hard right) and from there into my board.

    I compressed and hi+lopassed the summed signal, like you advised :)

    Had a couple of feedback issues at first, but these were mainly due to compressing too heavily, got that worked out pretty quickly.

    I felt I had to ride the group fader quite a lot, so I could turn down the choir during instrumental parts and so on because there was just too much ambience (people in the choir talking, clapping, ...) going on. That was probably because I had the mic gains up way too much because those kids were singing VERY softly most of the time. Directions for the choir were so-so. Kids moved around quite a lot (them being kids and all ;)) so exact mic positioning was close too impossible, but overall everything turned out ok. Was an interesting experience for sure, and a nice change from my usual stuff!

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    Replies
    1. oh yeah, this was an open air stage.
      also i experimented with the panning, so it might have been less extreme later on (more like 9-12-12-3 o'clock or something).

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