Microphones How to Handle Difficult Live Choir and Difficult MD

MrMagLit

Member
Hello there,

Firstly, I'd like to say that I have made a genuine effort to figure this one out myself, with much trouble. Any advice or opinions from someone knowledgeable would be terrific! Excuse the length - there are just a lot of details!

I'm the TD of a small high school with a pain-in-the-butt MD who thinks he's everything, with sprinkles on top... Our performances are all live, and made of a mashup of choral performances, dances, drama pieces, etc. Anyway, he refuses to place his choir anywhere but against a wall in a corner of the gymnatorium. The room has a 5-second echo if I'm lucky, so acoustics couldn't be worse. The mains were installed nicely, a couple dozen feet in the air. The issue is that if you place a microphone anywhere but onstage, feedback will occur at about 5 different frequencies, even with very little gain.

I'm trying to give volume to a 16-peice vocal jazz ensemble. I'd like to clarify: 16 of the (albeit highly talented) quietest high-school voices you will ever hear. Placing overhead mics is impractical... The only mics other than 57's and 58's in the inventory are 2 AKG C1000S's. They refuse to give me any volume before the start feeding back, which is understandable considering the room. I can place them facing exactly opposite to the speakers and still only catch 3 or 4 voices.

Next idea is to close-mic every individual in the choir. We have enough 57's and 58's for everybody... But I have the same gain problem because the vocalists are so quiet and can't hold the thing close to their lips for the life of them. It's also not desirable because the room is 125x75 feet and cable runs become ridiculous, and students trip over them. In addition, there are junior choirs who have specifically requested not to hold microphones, so managing all of them and their cables between acts is nearly impossible.

I am moderately experienced in sound, but I have no idea how to handle this anymore... Sound checks (which I get about 5 minutes for) become "WHY ARE YOUR MICS SO QUIET?" and "WHY ARE YOUR VOCALISTS SO QUIET?"

Any tips on how to make this louder would be much appreciated. The mixer is a Mackie Onyx 24.4, and my only signal processing is a stereo 31-band EQ (which I run the mains through). Mains are QSC 2 K8s and 2 QSC KSubs. Subs are on the floor, by the way.

Thanks,
MrMagLit
 
I feel for you! Part of learning to sing is learning to project. Sound reinforcement is (by its name and nature) "Reinforcement." There must be a sound there to begin with. Depending on the size of the room, many MDs would not use a sound system to begin with. I travel as a singer and sound-man with a small 30 piece ensemble, and yes, we do use reinforcement. Getting a good level is about getting the system as flat as possible usually with a graphic eq and quality speakers and mics, then rolling off unused frequencies which usually means cutting the bass. Still, even with perfect equipment, it all comes down to math. If the microphone can hear the speaker better than the singer, it is going to feedback. In a room with heavy resonance, it becomes near impossible to eliminate all sustains.
To me, this sounds more like a diplomatic problem at this point. My suggestion would be to entertain a conversation about not using the sound system other than for solos and announcements. This would also require another Miracle at showtime, a quiet audience!
 
Thanks for the sympathy!

I'm thinking that you're probably right...

The painful part is listening to teachers complain about "how much money we spent on all the dynamics and you can't get volume from them? They're the Swiss Army Knife of microphones and it's too quiet?" And I have to explain the speaker situation, every time...

Thanks again!
 
I mic our middle school choir with Behringer C2s.

Our choir risers are four sections with four levels each. One mic covers each section, so the mics are space about 8 feet apart. I just raise up a tripod boom stand in front of each riser, ~7 feet off the ground pointing a bit downward, about one foot in front of the first step.

My main goal was to be able to hear the quiet voices of the choir kids -- I have been successful.

Dynamic mics seem to drop off when an average voice is more than 2-3" away ... condensor mics seem to pick up more evenly as you increase distance.

The Behringer C2s are incredibly cheap mics so I can buy lots of them. Sound quality is debatable ... but our first goal is to be able to heaer the kids. I even Y these mics together -- two mics share a single input channel on my board -- with no ill effects.

My suggestion to you then is to pick up a couple of pairs of C2 (for a total price of $100) and try this out. It's a small investment to make for what might end up being a nice solution.
 
Sing for them properly. Then have on of the kids who are quiet sing. Should give them a visual.
 
Is the system feeding back at low frequencies, like under 100 Hz? I am wondering if the subs are part of the issue. Be sure to use the high pass filters on all vocal channels. I prefer to feed subs separately, and only send sources with bass energy to them. For a jazz ensemble, that would be kick drum, bass and piano.

The director's placement of the choir against the wall is a likely source of the problem. That wall is a boundary that reflects sound from the speakers directly into the mics. It makes total sense to place a choir like that if the performance is purely acoustic, and that's where the director got the idea. When the choir is miced for sound re-enforcement, the choir needs to be away from that wall.

I would stick with the 57s and 58s. I would put them on stands, two singers per mic. It would also be very worth experimenting with putting the choir in a tight group on risers. They might hear themselves better, which leads to them singing louder and better. In that case, two C1000s on booms stands should do the trick. Put them about two feet in front of the first row, and about level with the mouths of the top row. Add a hand held solo mic or two, as needed.

Remember that for every doubling of the number of mics, you lose 3 dB of gain before feedback. That's why I would use no more than 8 mics. Also heed the 3 to 1 rule. For every foot of distance from the source, the mics need to be spaced 3 feet apart. As for mass amounts of cables, you need a snake cable and maybe a sub snake.

I suggest asking the director for an hour or two on a rehearsal "tech day" just to experiment. Tell him you have some professional advice that you would like to try when there is plenty of time and little pressure. Hearing is believing. He might be more flexible if he hears good results. Often times, doing sound is as much psychology of working with musicians as it is knowing how to use the equipment. It's good to let them know your goal is for the the best sound you can achieve, along with making them comfortable with the setup. I've been doing this for 40 years, and have worked with everyone from church groups to internationally known jazz artists, and I'm still learning.
 
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The Behringer C2s are incredibly cheap mics so I can buy lots of them. Sound quality is debatable ... but our first goal is to be able to heaer the kids. I even Y these mics together -- two mics share a single input channel on my board -- with no ill effects.

My suggestion to you then is to pick up a couple of pairs of C2 (for a total price of $100) and try this out. It's a small investment to make for what might end up being a nice solution.

Trust me, a large diaphragm condenser is not going to provide more gain before feedback than an SM58, because the polar pattern is nowhere near as well controlled.

EDIT: Pardon my bad memory. I was thinking of the C1. The C2 is a small capsule, which would work fine for a choir.
 
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About 50% of the troublesome frequencies are under 180hz... Others sit around the usual 1K, and can go up to 4K. I'm debating driving the subs separately, though I'd have to use more XLR cable to reach it from the snake. Speaking of the snake, I'd love to move it closer to the choir, but there are an equal amount of inputs on the other side of the gym for the band (yes, they did that...), and several inputs that I need onstage for dancer's monitors, and mics for some other performances. These shows are like the paper mâché of theatre: keep slapping things on and hope it looks good in the end...

I figured the wall was one of the biggest issues as well. Positioning them elsewhere would bring the mics closer to the direction of the sound, but I wonder if you're right and it would still be better than that darned flat, cold, hard surface...

By the way, they are already on 3 risers. Slightly concave, 3 tiered.
 
Sounds like there are a lot of issues that could be addressed in different ways. Have you thought about a mic lesson in the vocal class? You could teach it, or if the MD insists on teaching it, they would be forced to do a little research.
 
Indeed I have!

Not sure how to go about doing it though... As a technician I'm not used to saying much more than "Check 1, 2, 3" into a microphone :)

Just stop them before they start rehearsing and say "Hold it with your fingertips, speak LOUD"? Do you thing they'll the be receptive? Outside of this school, I've only ever worked with at least somewhat experienced performers.

Also, when I first tried out the Mackie board (I'm used to A&H for analogue, and DiGiCo for digital), I thought I was going crazy with how high I had to push the preamps for anything even close to a healthy signal... I almost lost it on the board before I realized that one of the students, with her mature voice and stature, was giving me a god signal at a normal level. Phew. Not entirely me. Still surprised at how much gain I need though.

Not that it matters... As soon as I get the signal I can't push the master far past -20dB before the building shakes with feedback... ;)
 
This limerick scrawled into our stage manager podium seems oddly relevant:

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The MD is using the walls as a shell so they can hear themselves better, it is not the problem, if anything it helps, if they sing. C1000s are fine for choirs, they are not the best detailed mic but for choirs that is an advantage, you don't want to hear individual voices. What would help is a sketch of your room. It is not clear where in relation to the PA the choir is and that is really important. The C1000 can be changed from cardioid to hyper, if you are directly opposite the PA and have the hyper cap on then you will never get any gain. So send us a diagram and we can fix it.
 
About 50% of the troublesome frequencies are under 180hz...

Core vocal frequencies are from about 400hz to 4khz. That being said, things will not sound too natural (think telephone) with those cuts as we are very tuned in to harmonics and sub harmonics for articulation and providing a natural sound to the voice. When all else fails, you start by focusing on the core vocal range, and then try to build out in both directions as much as you can. If you have a problem below 200hz, you may have to limit those frequencies.
Now, here is the "catch 22"- Graphics EQs are a double edged sword. You may be able to insert a powerful notch to get rid of a problem, but now that notch is also missing from the performer's voice.
You said "against a wall in a corner" which sounds odd. The corner can actually help as the room forms a natural horn. However, if they are in the corner but lined up against only one wall then the advantage is lost as slapback becomes a problem. A diagram may help, but as I said in the first post, this may be more of a diplomatic or stubbornness problem/ Good luck!
 
The closest thing I have to a diagram at the moment is the most recent electrical plot on the main floor, so please excuse all the redundant information...

The main idea is the choir is the yellow block.
Monitors positioned on the floor are orange.
Subs on the floor are purple arrows.
Mains are about 30' up, pointed steeply downwards, and they are the pink arrows.

All arrows point in the same direction the speakers are pointed in...
 

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Wow, that is an interesting set up.

1st, what is in the choir monitor? If it is the choir mics then there is a major problem. If the MD thinks that the vocal mics should be in there then there is very little to do. The only thing that should be in there for their portion of the show is keyboard, if they are using an electric keyboard. If you use the following ideas with the vocal mics in the wedge then this will NOT work.

2nd I am curious on how you are running your mains. You show a LRC set up but say you only have two channels of EQ. So are the mains left and right and the center run out of one of those? The best way to run these would be to add an EQ on a matrix send and run the center separately. If you can't afford another EQ then i would suggest the following.

Make sure the center speaker is being fed off the SL speakers. Using the c1000's hyper cap set both mics to hyper. Place the mics in an XY array in the center of the choir arc. You will need to move it around after you do everything else to find the sweet spot. Now pan the mics hard left and right on the console and note which is which. If you set up this way one mic will be pointing at the SR speakers. Make sure this is the mic panned to the SL speakers. The other mic should be close to perpendicular to the SR speaker, since it is in hyper it should reject much of the signal from that side. Start there, now try panning both channels toward center a little bit, you should be able to add a little bit back to balance the sound a bit better, it may not work, but try.

If you can afford another EQ then you could play with how much of each mic went where and be able to use the center and SL speakers as the primary source and add in as much of SR as you could before feedback. Remember that the mic pointing at the speakers should be well down in that side.

Now people will chime in that this might not be the ideal way to mic a choir and they would be right. However, this should give you significantly more gain before feedback. If your MD truly wants good sound then they need to be behind the speakers, period. I would also ask the physics teacher to explain to the MD how sound works.

Good luck,

John
 
The closest thing I have to a diagram at the moment is the most recent electrical plot on the main floor, so please excuse all the redundant information...

The main idea is the choir is the yellow block.
Monitors positioned on the floor are orange.
Subs on the floor are purple arrows.
Mains are about 30' up, pointed steeply downwards, and they are the pink arrows.

All arrows point in the same direction the speakers are pointed in...
Two things, The first you are probably already doing: Needless to say, the only mics that should be folded into the monitors are solo mics, and announcement mic. Any time they are not actively in use, they should be muted. The second point is to remind the MD that the entire system was engineered for the sound source to be on the main STAGE, and that the altered location creates a lot of problems by putting the sound source in front of the speakers. The nice pink arrows are how we would wish speakers work, but dispersion at some frequencies (especially low freq) is almost 360.
 
I sit corrected! I am a total novice, and I can see the OP is way beyond my capabilities, but my feedback headaches went away when I learned how to set gain in the precious minutes before a show. I have a dbx driverack feedback eliminator that hasn't moved from storage since I learned how to set gain. It's surely beginnner's luck, but I wish the luck came before I spent the money on the feedback eliminator. Maybe it will help someone else.
 
1st, what is in the choir monitor? If it is the choir mics then there is a major problem. If the MD thinks that the vocal mics should be in there then there is very little to do. The only thing that should be in there for their portion of the show is keyboard, if they are using an electric keyboard. If you use the following ideas with the vocal mics in the wedge then this will NOT work.

Choir monitor, previously, was the TB mic (obviously), solos, and a tiny bit of the instruments that they may be singing with (keys, acoustic, etc). Unfortunately, I have to argue every time because they want the entire choir coming back through the monitor. The entire thing. Unfortunately, MD's needs always win and I have to return the entire mix to them. (Diplomatic an non-technical problem here, I know...) I may just cut it out for the next show and see if they notice, or at least reduce it significantly.

2nd I am curious on how you are running your mains. You show a LRC set up but say you only have two channels of EQ. So are the mains left and right and the center run out of one of those? The best way to run these would be to add an EQ on a matrix send and run the center separately. If you can't afford another EQ then i would suggest the following.

I have no idea how this place is hardwired, but after some testing a little while ago it looks like centre is a mono feed, even though there are only LR outputs to the system.

I'll try some of your suggestions! Quick question for all of you: are overheads going to be better than handhelds for each singer? I've done larger choirs before, and have never had to give each person their own mic... Sometimes two people will share, but typically I've always gone for XY and whatever is needed for solos.
 

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