How to build a simple yet very effective choral shell for $400.
The community based show-chorus I sing with, the Maple Leaf Singers, wanted to do something to improve the sound of our performance for our big fund-raising show - we sing over 15 times per year, but just a pair of shows bring in our critical revenue.
Massey Theatre, the place hosting the big shows, is a big box of a place, with a huge backstage and theatrical fly system. Our singing vanishes into the void, and we tend to yell because the sound balance is off - we can't hear each other. Yelling is not good and lowers our pitch, yet the audience despite our being miked to the limits of feedback, still can't hear us well.
The current option of choice - miking every performer - is not an option for a 60-member group. Nor is changing the venue. In desperation we decided to try sound reflectors, and to my modest surprise (I'm always surprised when something I build succeeds) - it worked better than we had hoped.
Consulting the local experts
First here's what researching with the local theatre people - the ones we consider to be keeners at their craft.They told us that a shell would do nothing for the audience, but would help us hear each other. This alerted us as to what to expect default, so that we weren't disappointed and could design around the default limits.
What our goals were
We wanted to, in decreasing importance:
1. Have the audience hear us - well duh! but today's audience wants volume
2. Hear each other - often taken for granted
3 Hear our monitors- without feedback
4 Hear the audience - this last is what makes it fun!
Studying the shapes of the commercial units, it turns out that a traditional choral shell - costing thousands of dollars and weighing many pounds, does not reflect the sound evenly - by design it scatters it within the choir, so that it primarily supports objective #2.
With modern materials, it seemed might be possible to satisfy more of the objectives, by focusing the sound at the audience, and by "piping" it from one side of the chorus to the other.
So what we built
Our choral shell system has two components, one not very visible, the other very much so. Both are made of the material Coroplast, the lightweight material using to make signs.
1. The invisible - but important! - black railing cover of coroplast
We now use this for all performances, as it is easy to set up and gives us consistent sound
2. The visible white shell, flown by the theatre system
This is only for use at the big theatre, directing some sound to the audience and some audience sound to us.
Note that it also acted as a "sonic pipe", transfering sound from riser-left to riser-right and vice-versa.
What it looks like: one segment, front and back:
I used 3 thin wires to bend the panel.
What it looked like in practice, with the segments all linked together with Velcro, flown and lit:
The wonderful Massey staff were keen to try it, and suggest improvements.
Results
The choral shell was very effective in a number of ways, and seemed to have no downside:
- The intra-choral sound was excellent: we could hear each other, didn’t yell, stayed on pitch, and could dis-regard monitors that were too loud or too quiet
- The shell apparently focused the audience attention on the choir, making us look closer and more intimate
- We could hear the audience a bit better; they sounded closer
- We had remarks like “Wow, you guys really had a lot of very difficult harmonies this year!”
- I think he choir most benefited – no-one’s voice was hoarse after 3 days of singing - the first time ever.
- Our pitch was good: I know that the piano/track never sounded sharp and our chorister with perfect pitch reports it was good
- The effect was like singing in the our normal rehearsal hall, perhaps with an even better unit sound - I could hear the ladies on either side and felt a solid crisp group sound. |
- and the cost was low - $400 for 10 sheets of Coroplast, lots of Velcro, and some wood.
SO if you are interested, let me know, and I'll post details of how to make your own.
Ken Rushton.
* The Massey Staff also borrowed a new high-grade overhead microphone that helped.
Thanks for posting this! Please do send me the plans. Thanks!
Posted by: Jack Pelham | Nov 05, 2021 at 10:31 AM
We have some of the same problems in our church. Please send me your plans!
Thanks!
Posted by: Cullene Hobbs | Feb 20, 2020 at 10:38 AM
I would love to get the plans for your choral shell. Our church choir has a hard time hearing each other when we sing on risers.
Posted by: Wes Parker | Nov 11, 2019 at 01:46 PM
Please send the plans. This sounds great!!
Posted by: Nate Bergey | Sep 28, 2019 at 02:14 PM
Hi, Ken!! What a genius you are! Let me know if you still could send plans for us. We are a small elementary school and have our programs in a gym....we need something!
Posted by: Terri Ellerbach | Dec 23, 2018 at 03:49 PM
I would love plans for my elementary school, please!
Posted by: Ashley | Dec 07, 2018 at 04:16 PM
Hi Ken,
Please send the plan. We are a small singing group, and have no budget for expensive panels, and our performance definitely need your design. Thank you very much!
Posted by: Young Lin | Jul 18, 2018 at 04:57 PM
I am the secretary of a rural parents music boosters program for our local Jr/Sr High. We would love to get the plans from you since we just can't currently finance a commercially produced unit for our kids.
Posted by: Renee Von Kiedrowski | Jul 08, 2018 at 08:49 AM
We have a small church with a choir of about 30 that we want to put a shell behind. Is it possible to use your system as a portable unit? Could you please send us your design? Thank you very much.
Posted by: Teresa Ellis | Jun 22, 2018 at 10:39 AM
Thanks for your info. Making some kind of shells has been on my mind for a bit since we have a perfect way to permanently mount them on the back wall of the choir loft in our church.
Weight and portability is not an issue, so I'm wondering what would be the best choice of material for acoustics? We could use plywood and even sandwich (double it) with space in between say 4" so it would be hollow. I would appreciate any thoughts you would have on this.
Thanks, Dan
Posted by: dan needham | May 03, 2018 at 01:05 PM
Please send the plans. This will be a cure for our University stage that we can afford!
Posted by: Jane Griffen | Apr 24, 2018 at 11:45 AM
Please send plans as soon as possible.
Posted by: Jane Griffen | Apr 20, 2018 at 03:36 PM
Hi Ken:
Thank you so much for your wonderful choral shell design.
We have five 4-step Wenger risers, which set up in an arc, so we needed a curved shell. So, we supported each of the “flying” sheets individually, so we could position each one separately behind the risers.
We supported the shell pieces with lighting stands (ADJ LTS-2 – http://www.adj.com/lts-2). These stands are rated to 80 lbs and extend up to 12 ft. We needed 5 of them and the total cost was ~$650 CDN ($109/each plus taxes and shipping).
The cross bars are 4 ft long and come with 4 bolts with wing nuts. We replaced the bolts with longer ones and bolted 7 ft long pieces of 1x4 to the cross members. We attached the flying shell pieces to the cross members with ¾ inch Velcro (3 18” strips per shell fragment).
The shell fragments were 4x8 pieces of coroplast. We put the Velcro strips slightly lower then midway (18” up from the bottom).
The other change we made was how we established the curve on each shell piece. We cut 1” slots @ 1ft intervals along both top and bottom edges of the shell pieces. We tied lengths of heavy fishing line (actually whipper snipper cord from a long deceased whipper snipper) into 44” lengths with knots at both ends and washers inside the knots. To create the curve you simply slip one end of the cord into a slot (with the washers at the back) then slip the other end of the cord into the matching slot on the far side of the coroplast sheet. These are easy to assemble and take apart.
It’s a bit tricky to get the length between the washers consistent. I tied a knot on the end of my roll of cord, cut the cord longer than needed and slid on both washers. Then I measured the 44” and marked the cord with a magic marker. Then I used that mark to locate the second knot. The mark needs to be just on the straight cord in front of the finished knot.
We tried several distances between cords and found that with 24” spacing the top edge of the shell had a bit of a wave between cords, but with 12” spacing the top edge of the shell was nice and straight.
Our total costs were $1300. All our costs were consistent with yours with the marked addition of the lighting stands. However we now have a sound shell with which the choir is totally pleased and which should last us for years.
Many thanks from all of us to you.
All the best
Eric White
Nelson Choral Society
Posted by: Eric White | Dec 16, 2016 at 09:49 AM
Please please send me the plans!!!
Posted by: Karen Wilmus | Dec 07, 2016 at 09:28 AM
I would be very appreciative if you could send me the plans!
Posted by: Chloe Vassmer | Apr 18, 2016 at 06:42 AM
I've posted the first of three articles on how to build a choral shell: http://www.musicscienceguy.com/2015/07/choral-shells-for-the-risers.html
This article focuses on making an acoustic cover for your risers.
I hope this helps. The second article is about the visible white upper riser, and will be a challenge to write.
Ken.
Posted by: Ken Rushton | Jul 01, 2015 at 03:26 PM
I serve as stage manager for The Palmetto Mastersingers in Columbia, SC. I would love to have a look at plans for your design. Do your plans allow for support of these curved panels from the ground instead of suspended from the ceiling? We have 3 level, 32'x12' risers when fully assembled. We would also require some sort of black panels to attach to the back of our risers for the area below the curved panels. Thousands of dollars for a shell is way out of budget for a volunteer non-profit group like us. We number anywhere from 50 to 80 singers depending on the year.
Posted by: Michael Stroupe | May 13, 2015 at 01:02 PM
Dear Ken: If I could have the plans, it would be a godsend for the very small HS Choir I am directing in two weeks for our Spring Concert, in a barn of church, and with an Admin that won't/can't see the necessity of actually amplifying a choir for the audience's sake, as well as for the students!
Posted by: Dr. JS Moir, DMA | May 05, 2015 at 11:27 AM
PS. do the lower part first - it gives you a faster setup. Cover the riser steps as well, but do be careful never to introduce a tripping hazard.
Ken.
Posted by: Ken Rushton | Apr 29, 2015 at 08:39 PM
Neil, RE: "could you tell me the thickness of the 'coroplast' you used? We here[Australia] have the option of, e.g: 5mm or 3mm"
I just measured mine, it is 4.12 mm. I would go with the heavier version, partly because it will be easier to handle. I expect the sound reflection will be slightly better with the thicker material.
Ken.
Posted by: Ken Rushton | Apr 29, 2015 at 08:36 PM
I may be a bit late with this ... but could you tell me the thickness of the 'coroplast' you used? We here[Australia] have the option of, e.g: 5mm or 3mm. I think the thicker the better, both for rigidity & sound reflection ... what is your view, please?
Posted by: Neil Marsh | Apr 28, 2015 at 01:39 AM
From your posting I assume you are retired now - as am I. I have been asked to build acoustic shells for our church choir and this seems to be the most effective, lightest, storable and inexpensive method available.
Can you send more information or build instructions??
Posted by: Philip Lehman | May 28, 2014 at 03:37 AM
Hi Ken,
I'd really like to see your plans for this. We're a 25-30 voice choir and $6K for a shell is out of the question. We often sing at outdoor venues and a variant of this could solve lots of problems!
Posted by: Andrew Adams | Feb 19, 2014 at 10:40 PM
Ken-
I am SO interested in getting all the details to build this type of shell. I teach music at a small elementary school. The building is very old, and the only "stage" is on one end of a sunken gym. Basically, there are big wooden doors that can be opened and a railing at the front of the doorway so audience could sit in chairs down on the gym floor and the kids could perform up behind the rail. Only problem is that they would be standing in a main hallway. We need a way to make a "back" to our stage to block sound and sight lines down that hall. Please help! :)
Posted by: Laura | Dec 13, 2013 at 12:45 PM
Sorry!
I am unable to do any major postings until Jan 6, when I retire to specialize in:
1. learning to play my jammer.
2. post fun things about Music.
I promise that I will post all that I know about the choral shell in January. I will finally have time to do so.
A tip for the meantime: I created 8" high riser step covers from coroplast. These were very successful.
The boost reflected sound and the stopping of sound sneaking around the back of the risers and making the sound muddy made it easier to hear each other and the audience seemed to like it.
Just take careful care that the feet can't catch on a protruding piece of plastic.
Ken.
Posted by: Ken Rushton | Dec 11, 2013 at 03:20 PM