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Acoustical Shell Outdoors with MicrophonesDate: June 28, 2009
Hi all and happy summer, We just finished the annual purgatorial ritual known as Commencement, here on the muggy shores of the eastern Mediterranean. The choir's sound outdoors was not great; trying to blend and balance with mics outdoors is hard. This is the only time in the year we are forced to use amplification. Has anyone had a good experience with using, or creating, an acoustical shell outdoors with microphones? best, Paul -- Paul S. Meers, DMus http://staff.aub.edu.lb/~pm05/ Director of Choral Music American University of Beirut Nicely Hall 403 e.mail: pm05(a)aub.edu.lb 961-1-353465, ext. 4041/4350 outside of Lebanon Replies (12): Threaded | Chronological
Stephen Stomps on June 28, 2009 3:19pm
Last summer, small groups I put together sang outside prior
to the Syracuse Symphony concert. We stood on steps in front of a
very large vernanda. The orchestra's professional sound guy set up
mikcs and monitors for us. We heard ourselves very well and we
could be heard wonderfully through the truck size speakers. Far
Better than shells for everybody.
on June 28, 2009 4:09pm
I wonder if it is a microphone placement issue rather than an acoustic shell issue. I am thinking that if you have small diaphragm condenser mics placed just right, your sound will be the same out the speakers as it is in rehearsals. The small diaphragm will only pick up the ensemble and not the audience...but if you have acoustic shells behind your singers, some of that audience noise might reflect off the shells and be amplified out the main speakers.
Scott Wickham
Lafayette, CO
on June 28, 2009 5:30pm
The shell is probably the most important thing in working outdoors. More than mic placement, the important thing is the type and quality of mic. Small diaphragm is not necessarily the most important thing, as is the pickup pattern. However, you will not get good results with your garden variety hand held mic in overhead micing.
Two mid price range mics that are rated well for micing choirs are the AKG C1000 and the Shure SM-81. They are both condenser mics and do happen to be small diaphragm. However, they have a cardioid pickup patern which means they pick up what is in front of them and not so much to the sides or to the rear. The best result is to put them in an X-Y pattern.
Mic placement is important. It should be an onverhead micing which is far enough away that it does not pick up individual voices. The problem with that and why not all mics are equal is a sound issue called proximity effect. Basically the farther away you are from the microphone, the more the frequecies change. You lose frequencies at both ends of the range with most microphones. Also, where you are amplifying, the more chance you have of feedback. So getting it right is very tricky. It is next to impossible if you don't have the correct equiment for it to start out.
Mark
on June 29, 2009 7:07am
Just to clarify what I mean by "X-Y" pattern is that the mics are mounted at a 90 degree angle to the chorus facing in opposite directions. This way you get more of the chorus and you get less individual voices than if the mic were mounted straight on. In this case, you would also eliminate the problem that Scott identified with sounds bouncing back from the shell that you do not want in your sound reinforcement.
Omnidirectional mics can be used along with this with a larger group that is more spread out. They can be placed to the sides further out. However, these do pick up from the back as well. So if there is going to be noise in the audience, you will probably want some kind of isolation on the very rear of the mic. Something like the SM Pro Mic Thing would do the job. You just would adjust it so it only isolates the back and not the sides.
Mark
on June 29, 2009 9:07am
What a timely post! I am about to conduct, on July 10, a production of Carmina Burana with 44 singers+ soloists (and fire dancers, oh my!). We will be under a saddlespan tent with back. We just met yesterday to try and figure out mics etc. and realized we probably need a shell. I've spoken to a couple of production companies that have worked with the saddlespan tent and orchestras, some with choirs as well. Any ideas from folks about choirs under these types of tents? (Made by a company called Tentology?) I'll send our sound guy a link to this page, too. Thanks, wonderful Choralnet community!!
on June 29, 2009 10:22am
Another excellent mic I'd have to recommend is the NT5 by Rode. They run about $400 for a pair. I've had good success with them, at least for smaller ensembles (approx. 20). I also put these in an X-Y pattern.
Dan
on June 29, 2009 10:55am
Hi Paul,
My groups sing for graduation at the end of the year outside on the newly turfed football field. We have to reach both sides of the field filled with an enormous amount of people. The only way for them to hear the solo’s within the choir arrangements along with the harmonies, I prerecord my choir. We sing to the prerecording and everyone gets to hear every detail of the piece. Yes, you could try to buy the better mic system out there and spend a lot of money, but you still have to contend with the wind blowing and of course the sound system still not up to par when hearing the back row harmonies.
A fellow musician,
Heather
on June 30, 2009 1:43am
Dear Mark and Scott,
When you say the shell "is the most important thing," I assume you mean it's basically indispensible? I think it would allow the singers to hear each other better, and "feel" less diffused. I would also hope to lessen the main problem, which is lots of individual voices coming in and out.
What I have been doing is grouping each voice part around one or two mics, not a set of mics at the front, to better acheive balance. More like a studio approach. But this also results in that individual voice problem.
Any more thoughts?
Paul
on June 30, 2009 5:17am
Hi Paul,
I say the shell is important because it pushes the sound forward into both the audience's ears as well as the microphones. Any venue but especially outside the sound can go anywere including straight up. The shell will help greatly to prevent that.
Small groups will work good as well. You have less control over the sound of your ensemble at that point (particularly blend and balance) than the sound engineer has. If you have a sound man who is musical and not just a "meter reader" you should be okay doing it that way.
If you are micing the whole ensemble the way that they normally stand then you have more control over that whereas the sound man controls how much gain on the volume.
on June 30, 2009 7:19am
I've heard great things about Rode mics, Dan. But I have never tried them. Sounds like they are priced comparable to the AKG C1000 if you buy a pair. One thing that is interesting about the C1000 is that they can be battery operated rather than having to have phantom power to power the condenser in the mic. That may be a consideration for some people depending on the age and such of the sound equipment being used.
I like the Shure SM81's the best for several reasons but they are more expensive unless you can find some good used ones like I did on Ebay. They are also excellent for recording choirs as well as sound reinforcement. They have been the industry standard for this use for quite a while, similar to the way the Shure SM58 has been the industry standard for a handheld vocal mic.
Mark
on July 5, 2009 5:18pm
We used the Rode NT5s for the first time during our graduation in our stadium, and they were wonderful. Not only did they amplify the choir (which was the intention), but they also easily amplified the band that was 30 yds away. What makes the NT5 unique is its size. They are about the size of a dry-erase marker, and the diaphragm is 1/2 inch. This allows more flexibility in mic placement and more volume without feedback.
Scott
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